author | ohair |
Wed, 06 Apr 2011 22:06:11 -0700 | |
changeset 9035 | 1255eb81cc2f |
parent 7803 | 56bc97d69d93 |
child 12681 | ebee74a1fd8c |
permissions | -rw-r--r-- |
2 | 1 |
/* |
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* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package java.util.prefs; |
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import java.util.*; |
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import java.io.*; |
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import java.security.AccessController; |
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import java.security.PrivilegedAction; |
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// These imports needed only as a workaround for a JavaDoc bug |
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import java.lang.Integer; |
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import java.lang.Long; |
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import java.lang.Float; |
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import java.lang.Double; |
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/** |
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* This class provides a skeletal implementation of the {@link Preferences} |
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* class, greatly easing the task of implementing it. |
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* |
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* <p><strong>This class is for <tt>Preferences</tt> implementers only. |
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* Normal users of the <tt>Preferences</tt> facility should have no need to |
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* consult this documentation. The {@link Preferences} documentation |
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* should suffice.</strong> |
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* |
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* <p>Implementors must override the nine abstract service-provider interface |
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* (SPI) methods: {@link #getSpi(String)}, {@link #putSpi(String,String)}, |
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* {@link #removeSpi(String)}, {@link #childSpi(String)}, {@link |
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* #removeNodeSpi()}, {@link #keysSpi()}, {@link #childrenNamesSpi()}, {@link |
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* #syncSpi()} and {@link #flushSpi()}. All of the concrete methods specify |
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* precisely how they are implemented atop these SPI methods. The implementor |
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* may, at his discretion, override one or more of the concrete methods if the |
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* default implementation is unsatisfactory for any reason, such as |
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* performance. |
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* |
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* <p>The SPI methods fall into three groups concerning exception |
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* behavior. The <tt>getSpi</tt> method should never throw exceptions, but it |
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* doesn't really matter, as any exception thrown by this method will be |
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* intercepted by {@link #get(String,String)}, which will return the specified |
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* default value to the caller. The <tt>removeNodeSpi, keysSpi, |
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* childrenNamesSpi, syncSpi</tt> and <tt>flushSpi</tt> methods are specified |
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* to throw {@link BackingStoreException}, and the implementation is required |
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* to throw this checked exception if it is unable to perform the operation. |
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* The exception propagates outward, causing the corresponding API method |
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* to fail. |
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* |
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* <p>The remaining SPI methods {@link #putSpi(String,String)}, {@link |
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* #removeSpi(String)} and {@link #childSpi(String)} have more complicated |
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* exception behavior. They are not specified to throw |
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* <tt>BackingStoreException</tt>, as they can generally obey their contracts |
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* even if the backing store is unavailable. This is true because they return |
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* no information and their effects are not required to become permanent until |
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* a subsequent call to {@link Preferences#flush()} or |
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* {@link Preferences#sync()}. Generally speaking, these SPI methods should not |
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* throw exceptions. In some implementations, there may be circumstances |
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* under which these calls cannot even enqueue the requested operation for |
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* later processing. Even under these circumstances it is generally better to |
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* simply ignore the invocation and return, rather than throwing an |
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* exception. Under these circumstances, however, all subsequent invocations |
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* of <tt>flush()</tt> and <tt>sync</tt> should return <tt>false</tt>, as |
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* returning <tt>true</tt> would imply that all previous operations had |
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* successfully been made permanent. |
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* |
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* <p>There is one circumstance under which <tt>putSpi, removeSpi and |
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* childSpi</tt> <i>should</i> throw an exception: if the caller lacks |
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* sufficient privileges on the underlying operating system to perform the |
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* requested operation. This will, for instance, occur on most systems |
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* if a non-privileged user attempts to modify system preferences. |
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* (The required privileges will vary from implementation to |
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* implementation. On some implementations, they are the right to modify the |
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* contents of some directory in the file system; on others they are the right |
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* to modify contents of some key in a registry.) Under any of these |
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* circumstances, it would generally be undesirable to let the program |
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* continue executing as if these operations would become permanent at a later |
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* time. While implementations are not required to throw an exception under |
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* these circumstances, they are encouraged to do so. A {@link |
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* SecurityException} would be appropriate. |
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* |
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* <p>Most of the SPI methods require the implementation to read or write |
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* information at a preferences node. The implementor should beware of the |
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* fact that another VM may have concurrently deleted this node from the |
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* backing store. It is the implementation's responsibility to recreate the |
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* node if it has been deleted. |
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* |
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* <p>Implementation note: In Sun's default <tt>Preferences</tt> |
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* implementations, the user's identity is inherited from the underlying |
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* operating system and does not change for the lifetime of the virtual |
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* machine. It is recognized that server-side <tt>Preferences</tt> |
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* implementations may have the user identity change from request to request, |
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* implicitly passed to <tt>Preferences</tt> methods via the use of a |
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* static {@link ThreadLocal} instance. Authors of such implementations are |
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* <i>strongly</i> encouraged to determine the user at the time preferences |
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* are accessed (for example by the {@link #get(String,String)} or {@link |
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* #put(String,String)} method) rather than permanently associating a user |
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* with each <tt>Preferences</tt> instance. The latter behavior conflicts |
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* with normal <tt>Preferences</tt> usage and would lead to great confusion. |
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* |
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* @author Josh Bloch |
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* @see Preferences |
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* @since 1.4 |
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*/ |
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public abstract class AbstractPreferences extends Preferences { |
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/** |
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* Our name relative to parent. |
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*/ |
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private final String name; |
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/** |
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* Our absolute path name. |
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*/ |
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private final String absolutePath; |
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/** |
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* Our parent node. |
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*/ |
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final AbstractPreferences parent; |
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/** |
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* Our root node. |
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*/ |
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private final AbstractPreferences root; // Relative to this node |
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/** |
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* This field should be <tt>true</tt> if this node did not exist in the |
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* backing store prior to the creation of this object. The field |
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* is initialized to false, but may be set to true by a subclass |
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* constructor (and should not be modified thereafter). This field |
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* indicates whether a node change event should be fired when |
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* creation is complete. |
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*/ |
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protected boolean newNode = false; |
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/** |
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* All known unremoved children of this node. (This "cache" is consulted |
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* prior to calling childSpi() or getChild(). |
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*/ |
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private Map<String, AbstractPreferences> kidCache = new HashMap<>(); |
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/** |
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* This field is used to keep track of whether or not this node has |
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* been removed. Once it's set to true, it will never be reset to false. |
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*/ |
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private boolean removed = false; |
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/** |
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* Registered preference change listeners. |
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*/ |
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private PreferenceChangeListener[] prefListeners = |
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new PreferenceChangeListener[0]; |
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/** |
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* Registered node change listeners. |
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*/ |
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private NodeChangeListener[] nodeListeners = new NodeChangeListener[0]; |
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/** |
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* An object whose monitor is used to lock this node. This object |
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* is used in preference to the node itself to reduce the likelihood of |
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* intentional or unintentional denial of service due to a locked node. |
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* To avoid deadlock, a node is <i>never</i> locked by a thread that |
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* holds a lock on a descendant of that node. |
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*/ |
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protected final Object lock = new Object(); |
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/** |
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* Creates a preference node with the specified parent and the specified |
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* name relative to its parent. |
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* |
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* @param parent the parent of this preference node, or null if this |
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* is the root. |
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* @param name the name of this preference node, relative to its parent, |
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* or <tt>""</tt> if this is the root. |
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* @throws IllegalArgumentException if <tt>name</tt> contains a slash |
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* (<tt>'/'</tt>), or <tt>parent</tt> is <tt>null</tt> and |
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* name isn't <tt>""</tt>. |
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*/ |
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protected AbstractPreferences(AbstractPreferences parent, String name) { |
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if (parent==null) { |
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if (!name.equals("")) |
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throw new IllegalArgumentException("Root name '"+name+ |
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"' must be \"\""); |
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this.absolutePath = "/"; |
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root = this; |
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} else { |
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if (name.indexOf('/') != -1) |
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throw new IllegalArgumentException("Name '" + name + |
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"' contains '/'"); |
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if (name.equals("")) |
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throw new IllegalArgumentException("Illegal name: empty string"); |
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root = parent.root; |
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absolutePath = (parent==root ? "/" + name |
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: parent.absolutePath() + "/" + name); |
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} |
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this.name = name; |
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this.parent = parent; |
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} |
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/** |
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* Implements the <tt>put</tt> method as per the specification in |
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* {@link Preferences#put(String,String)}. |
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* |
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* <p>This implementation checks that the key and value are legal, |
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* obtains this preference node's lock, checks that the node |
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* has not been removed, invokes {@link #putSpi(String,String)}, and if |
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* there are any preference change listeners, enqueues a notification |
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* event for processing by the event dispatch thread. |
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* |
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* @param key key with which the specified value is to be associated. |
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* @param value value to be associated with the specified key. |
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* @throws NullPointerException if key or value is <tt>null</tt>. |
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* @throws IllegalArgumentException if <tt>key.length()</tt> exceeds |
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* <tt>MAX_KEY_LENGTH</tt> or if <tt>value.length</tt> exceeds |
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* <tt>MAX_VALUE_LENGTH</tt>. |
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* @throws IllegalStateException if this node (or an ancestor) has been |
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* removed with the {@link #removeNode()} method. |
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*/ |
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public void put(String key, String value) { |
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if (key==null || value==null) |
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throw new NullPointerException(); |
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if (key.length() > MAX_KEY_LENGTH) |
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throw new IllegalArgumentException("Key too long: "+key); |
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if (value.length() > MAX_VALUE_LENGTH) |
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throw new IllegalArgumentException("Value too long: "+value); |
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synchronized(lock) { |
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if (removed) |
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throw new IllegalStateException("Node has been removed."); |
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putSpi(key, value); |
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enqueuePreferenceChangeEvent(key, value); |
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} |
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} |
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/** |
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* Implements the <tt>get</tt> method as per the specification in |
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* {@link Preferences#get(String,String)}. |
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* |
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* <p>This implementation first checks to see if <tt>key</tt> is |
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* <tt>null</tt> throwing a <tt>NullPointerException</tt> if this is |
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* the case. Then it obtains this preference node's lock, |
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* checks that the node has not been removed, invokes {@link |
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* #getSpi(String)}, and returns the result, unless the <tt>getSpi</tt> |
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* invocation returns <tt>null</tt> or throws an exception, in which case |
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* this invocation returns <tt>def</tt>. |
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* |
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* @param key key whose associated value is to be returned. |
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* @param def the value to be returned in the event that this |
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* preference node has no value associated with <tt>key</tt>. |
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* @return the value associated with <tt>key</tt>, or <tt>def</tt> |
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* if no value is associated with <tt>key</tt>. |
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* @throws IllegalStateException if this node (or an ancestor) has been |
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* removed with the {@link #removeNode()} method. |
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* @throws NullPointerException if key is <tt>null</tt>. (A |
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* <tt>null</tt> default <i>is</i> permitted.) |
|
277 |
*/ |
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278 |
public String get(String key, String def) { |
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279 |
if (key==null) |
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280 |
throw new NullPointerException("Null key"); |
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synchronized(lock) { |
|
282 |
if (removed) |
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throw new IllegalStateException("Node has been removed."); |
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284 |
||
285 |
String result = null; |
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286 |
try { |
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result = getSpi(key); |
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} catch (Exception e) { |
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// Ignoring exception causes default to be returned |
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290 |
} |
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return (result==null ? def : result); |
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292 |
} |
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293 |
} |
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294 |
||
295 |
/** |
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296 |
* Implements the <tt>remove(String)</tt> method as per the specification |
|
297 |
* in {@link Preferences#remove(String)}. |
|
298 |
* |
|
299 |
* <p>This implementation obtains this preference node's lock, |
|
300 |
* checks that the node has not been removed, invokes |
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* {@link #removeSpi(String)} and if there are any preference |
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302 |
* change listeners, enqueues a notification event for processing by the |
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303 |
* event dispatch thread. |
|
304 |
* |
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305 |
* @param key key whose mapping is to be removed from the preference node. |
|
306 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
307 |
* removed with the {@link #removeNode()} method. |
|
308 |
*/ |
|
309 |
public void remove(String key) { |
|
310 |
synchronized(lock) { |
|
311 |
if (removed) |
|
312 |
throw new IllegalStateException("Node has been removed."); |
|
313 |
||
314 |
removeSpi(key); |
|
315 |
enqueuePreferenceChangeEvent(key, null); |
|
316 |
} |
|
317 |
} |
|
318 |
||
319 |
/** |
|
320 |
* Implements the <tt>clear</tt> method as per the specification in |
|
321 |
* {@link Preferences#clear()}. |
|
322 |
* |
|
323 |
* <p>This implementation obtains this preference node's lock, |
|
324 |
* invokes {@link #keys()} to obtain an array of keys, and |
|
325 |
* iterates over the array invoking {@link #remove(String)} on each key. |
|
326 |
* |
|
327 |
* @throws BackingStoreException if this operation cannot be completed |
|
328 |
* due to a failure in the backing store, or inability to |
|
329 |
* communicate with it. |
|
330 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
331 |
* removed with the {@link #removeNode()} method. |
|
332 |
*/ |
|
333 |
public void clear() throws BackingStoreException { |
|
334 |
synchronized(lock) { |
|
335 |
String[] keys = keys(); |
|
336 |
for (int i=0; i<keys.length; i++) |
|
337 |
remove(keys[i]); |
|
338 |
} |
|
339 |
} |
|
340 |
||
341 |
/** |
|
342 |
* Implements the <tt>putInt</tt> method as per the specification in |
|
343 |
* {@link Preferences#putInt(String,int)}. |
|
344 |
* |
|
345 |
* <p>This implementation translates <tt>value</tt> to a string with |
|
346 |
* {@link Integer#toString(int)} and invokes {@link #put(String,String)} |
|
347 |
* on the result. |
|
348 |
* |
|
349 |
* @param key key with which the string form of value is to be associated. |
|
350 |
* @param value value whose string form is to be associated with key. |
|
351 |
* @throws NullPointerException if key is <tt>null</tt>. |
|
352 |
* @throws IllegalArgumentException if <tt>key.length()</tt> exceeds |
|
353 |
* <tt>MAX_KEY_LENGTH</tt>. |
|
354 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
355 |
* removed with the {@link #removeNode()} method. |
|
356 |
*/ |
|
357 |
public void putInt(String key, int value) { |
|
358 |
put(key, Integer.toString(value)); |
|
359 |
} |
|
360 |
||
361 |
/** |
|
362 |
* Implements the <tt>getInt</tt> method as per the specification in |
|
363 |
* {@link Preferences#getInt(String,int)}. |
|
364 |
* |
|
365 |
* <p>This implementation invokes {@link #get(String,String) <tt>get(key, |
|
366 |
* null)</tt>}. If the return value is non-null, the implementation |
|
367 |
* attempts to translate it to an <tt>int</tt> with |
|
368 |
* {@link Integer#parseInt(String)}. If the attempt succeeds, the return |
|
369 |
* value is returned by this method. Otherwise, <tt>def</tt> is returned. |
|
370 |
* |
|
371 |
* @param key key whose associated value is to be returned as an int. |
|
372 |
* @param def the value to be returned in the event that this |
|
373 |
* preference node has no value associated with <tt>key</tt> |
|
374 |
* or the associated value cannot be interpreted as an int. |
|
375 |
* @return the int value represented by the string associated with |
|
376 |
* <tt>key</tt> in this preference node, or <tt>def</tt> if the |
|
377 |
* associated value does not exist or cannot be interpreted as |
|
378 |
* an int. |
|
379 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
380 |
* removed with the {@link #removeNode()} method. |
|
381 |
* @throws NullPointerException if <tt>key</tt> is <tt>null</tt>. |
|
382 |
*/ |
|
383 |
public int getInt(String key, int def) { |
|
384 |
int result = def; |
|
385 |
try { |
|
386 |
String value = get(key, null); |
|
387 |
if (value != null) |
|
388 |
result = Integer.parseInt(value); |
|
389 |
} catch (NumberFormatException e) { |
|
390 |
// Ignoring exception causes specified default to be returned |
|
391 |
} |
|
392 |
||
393 |
return result; |
|
394 |
} |
|
395 |
||
396 |
/** |
|
397 |
* Implements the <tt>putLong</tt> method as per the specification in |
|
398 |
* {@link Preferences#putLong(String,long)}. |
|
399 |
* |
|
400 |
* <p>This implementation translates <tt>value</tt> to a string with |
|
401 |
* {@link Long#toString(long)} and invokes {@link #put(String,String)} |
|
402 |
* on the result. |
|
403 |
* |
|
404 |
* @param key key with which the string form of value is to be associated. |
|
405 |
* @param value value whose string form is to be associated with key. |
|
406 |
* @throws NullPointerException if key is <tt>null</tt>. |
|
407 |
* @throws IllegalArgumentException if <tt>key.length()</tt> exceeds |
|
408 |
* <tt>MAX_KEY_LENGTH</tt>. |
|
409 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
410 |
* removed with the {@link #removeNode()} method. |
|
411 |
*/ |
|
412 |
public void putLong(String key, long value) { |
|
413 |
put(key, Long.toString(value)); |
|
414 |
} |
|
415 |
||
416 |
/** |
|
417 |
* Implements the <tt>getLong</tt> method as per the specification in |
|
418 |
* {@link Preferences#getLong(String,long)}. |
|
419 |
* |
|
420 |
* <p>This implementation invokes {@link #get(String,String) <tt>get(key, |
|
421 |
* null)</tt>}. If the return value is non-null, the implementation |
|
422 |
* attempts to translate it to a <tt>long</tt> with |
|
423 |
* {@link Long#parseLong(String)}. If the attempt succeeds, the return |
|
424 |
* value is returned by this method. Otherwise, <tt>def</tt> is returned. |
|
425 |
* |
|
426 |
* @param key key whose associated value is to be returned as a long. |
|
427 |
* @param def the value to be returned in the event that this |
|
428 |
* preference node has no value associated with <tt>key</tt> |
|
429 |
* or the associated value cannot be interpreted as a long. |
|
430 |
* @return the long value represented by the string associated with |
|
431 |
* <tt>key</tt> in this preference node, or <tt>def</tt> if the |
|
432 |
* associated value does not exist or cannot be interpreted as |
|
433 |
* a long. |
|
434 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
435 |
* removed with the {@link #removeNode()} method. |
|
436 |
* @throws NullPointerException if <tt>key</tt> is <tt>null</tt>. |
|
437 |
*/ |
|
438 |
public long getLong(String key, long def) { |
|
439 |
long result = def; |
|
440 |
try { |
|
441 |
String value = get(key, null); |
|
442 |
if (value != null) |
|
443 |
result = Long.parseLong(value); |
|
444 |
} catch (NumberFormatException e) { |
|
445 |
// Ignoring exception causes specified default to be returned |
|
446 |
} |
|
447 |
||
448 |
return result; |
|
449 |
} |
|
450 |
||
451 |
/** |
|
452 |
* Implements the <tt>putBoolean</tt> method as per the specification in |
|
453 |
* {@link Preferences#putBoolean(String,boolean)}. |
|
454 |
* |
|
455 |
* <p>This implementation translates <tt>value</tt> to a string with |
|
456 |
* {@link String#valueOf(boolean)} and invokes {@link #put(String,String)} |
|
457 |
* on the result. |
|
458 |
* |
|
459 |
* @param key key with which the string form of value is to be associated. |
|
460 |
* @param value value whose string form is to be associated with key. |
|
461 |
* @throws NullPointerException if key is <tt>null</tt>. |
|
462 |
* @throws IllegalArgumentException if <tt>key.length()</tt> exceeds |
|
463 |
* <tt>MAX_KEY_LENGTH</tt>. |
|
464 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
465 |
* removed with the {@link #removeNode()} method. |
|
466 |
*/ |
|
467 |
public void putBoolean(String key, boolean value) { |
|
468 |
put(key, String.valueOf(value)); |
|
469 |
} |
|
470 |
||
471 |
/** |
|
472 |
* Implements the <tt>getBoolean</tt> method as per the specification in |
|
473 |
* {@link Preferences#getBoolean(String,boolean)}. |
|
474 |
* |
|
475 |
* <p>This implementation invokes {@link #get(String,String) <tt>get(key, |
|
476 |
* null)</tt>}. If the return value is non-null, it is compared with |
|
477 |
* <tt>"true"</tt> using {@link String#equalsIgnoreCase(String)}. If the |
|
478 |
* comparison returns <tt>true</tt>, this invocation returns |
|
479 |
* <tt>true</tt>. Otherwise, the original return value is compared with |
|
480 |
* <tt>"false"</tt>, again using {@link String#equalsIgnoreCase(String)}. |
|
481 |
* If the comparison returns <tt>true</tt>, this invocation returns |
|
482 |
* <tt>false</tt>. Otherwise, this invocation returns <tt>def</tt>. |
|
483 |
* |
|
484 |
* @param key key whose associated value is to be returned as a boolean. |
|
485 |
* @param def the value to be returned in the event that this |
|
486 |
* preference node has no value associated with <tt>key</tt> |
|
487 |
* or the associated value cannot be interpreted as a boolean. |
|
488 |
* @return the boolean value represented by the string associated with |
|
489 |
* <tt>key</tt> in this preference node, or <tt>def</tt> if the |
|
490 |
* associated value does not exist or cannot be interpreted as |
|
491 |
* a boolean. |
|
492 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
493 |
* removed with the {@link #removeNode()} method. |
|
494 |
* @throws NullPointerException if <tt>key</tt> is <tt>null</tt>. |
|
495 |
*/ |
|
496 |
public boolean getBoolean(String key, boolean def) { |
|
497 |
boolean result = def; |
|
498 |
String value = get(key, null); |
|
499 |
if (value != null) { |
|
500 |
if (value.equalsIgnoreCase("true")) |
|
501 |
result = true; |
|
502 |
else if (value.equalsIgnoreCase("false")) |
|
503 |
result = false; |
|
504 |
} |
|
505 |
||
506 |
return result; |
|
507 |
} |
|
508 |
||
509 |
/** |
|
510 |
* Implements the <tt>putFloat</tt> method as per the specification in |
|
511 |
* {@link Preferences#putFloat(String,float)}. |
|
512 |
* |
|
513 |
* <p>This implementation translates <tt>value</tt> to a string with |
|
514 |
* {@link Float#toString(float)} and invokes {@link #put(String,String)} |
|
515 |
* on the result. |
|
516 |
* |
|
517 |
* @param key key with which the string form of value is to be associated. |
|
518 |
* @param value value whose string form is to be associated with key. |
|
519 |
* @throws NullPointerException if key is <tt>null</tt>. |
|
520 |
* @throws IllegalArgumentException if <tt>key.length()</tt> exceeds |
|
521 |
* <tt>MAX_KEY_LENGTH</tt>. |
|
522 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
523 |
* removed with the {@link #removeNode()} method. |
|
524 |
*/ |
|
525 |
public void putFloat(String key, float value) { |
|
526 |
put(key, Float.toString(value)); |
|
527 |
} |
|
528 |
||
529 |
/** |
|
530 |
* Implements the <tt>getFloat</tt> method as per the specification in |
|
531 |
* {@link Preferences#getFloat(String,float)}. |
|
532 |
* |
|
533 |
* <p>This implementation invokes {@link #get(String,String) <tt>get(key, |
|
534 |
* null)</tt>}. If the return value is non-null, the implementation |
|
535 |
* attempts to translate it to an <tt>float</tt> with |
|
536 |
* {@link Float#parseFloat(String)}. If the attempt succeeds, the return |
|
537 |
* value is returned by this method. Otherwise, <tt>def</tt> is returned. |
|
538 |
* |
|
539 |
* @param key key whose associated value is to be returned as a float. |
|
540 |
* @param def the value to be returned in the event that this |
|
541 |
* preference node has no value associated with <tt>key</tt> |
|
542 |
* or the associated value cannot be interpreted as a float. |
|
543 |
* @return the float value represented by the string associated with |
|
544 |
* <tt>key</tt> in this preference node, or <tt>def</tt> if the |
|
545 |
* associated value does not exist or cannot be interpreted as |
|
546 |
* a float. |
|
547 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
548 |
* removed with the {@link #removeNode()} method. |
|
549 |
* @throws NullPointerException if <tt>key</tt> is <tt>null</tt>. |
|
550 |
*/ |
|
551 |
public float getFloat(String key, float def) { |
|
552 |
float result = def; |
|
553 |
try { |
|
554 |
String value = get(key, null); |
|
555 |
if (value != null) |
|
556 |
result = Float.parseFloat(value); |
|
557 |
} catch (NumberFormatException e) { |
|
558 |
// Ignoring exception causes specified default to be returned |
|
559 |
} |
|
560 |
||
561 |
return result; |
|
562 |
} |
|
563 |
||
564 |
/** |
|
565 |
* Implements the <tt>putDouble</tt> method as per the specification in |
|
566 |
* {@link Preferences#putDouble(String,double)}. |
|
567 |
* |
|
568 |
* <p>This implementation translates <tt>value</tt> to a string with |
|
569 |
* {@link Double#toString(double)} and invokes {@link #put(String,String)} |
|
570 |
* on the result. |
|
571 |
* |
|
572 |
* @param key key with which the string form of value is to be associated. |
|
573 |
* @param value value whose string form is to be associated with key. |
|
574 |
* @throws NullPointerException if key is <tt>null</tt>. |
|
575 |
* @throws IllegalArgumentException if <tt>key.length()</tt> exceeds |
|
576 |
* <tt>MAX_KEY_LENGTH</tt>. |
|
577 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
578 |
* removed with the {@link #removeNode()} method. |
|
579 |
*/ |
|
580 |
public void putDouble(String key, double value) { |
|
581 |
put(key, Double.toString(value)); |
|
582 |
} |
|
583 |
||
584 |
/** |
|
585 |
* Implements the <tt>getDouble</tt> method as per the specification in |
|
586 |
* {@link Preferences#getDouble(String,double)}. |
|
587 |
* |
|
588 |
* <p>This implementation invokes {@link #get(String,String) <tt>get(key, |
|
589 |
* null)</tt>}. If the return value is non-null, the implementation |
|
590 |
* attempts to translate it to an <tt>double</tt> with |
|
591 |
* {@link Double#parseDouble(String)}. If the attempt succeeds, the return |
|
592 |
* value is returned by this method. Otherwise, <tt>def</tt> is returned. |
|
593 |
* |
|
594 |
* @param key key whose associated value is to be returned as a double. |
|
595 |
* @param def the value to be returned in the event that this |
|
596 |
* preference node has no value associated with <tt>key</tt> |
|
597 |
* or the associated value cannot be interpreted as a double. |
|
598 |
* @return the double value represented by the string associated with |
|
599 |
* <tt>key</tt> in this preference node, or <tt>def</tt> if the |
|
600 |
* associated value does not exist or cannot be interpreted as |
|
601 |
* a double. |
|
602 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
603 |
* removed with the {@link #removeNode()} method. |
|
604 |
* @throws NullPointerException if <tt>key</tt> is <tt>null</tt>. |
|
605 |
*/ |
|
606 |
public double getDouble(String key, double def) { |
|
607 |
double result = def; |
|
608 |
try { |
|
609 |
String value = get(key, null); |
|
610 |
if (value != null) |
|
611 |
result = Double.parseDouble(value); |
|
612 |
} catch (NumberFormatException e) { |
|
613 |
// Ignoring exception causes specified default to be returned |
|
614 |
} |
|
615 |
||
616 |
return result; |
|
617 |
} |
|
618 |
||
619 |
/** |
|
620 |
* Implements the <tt>putByteArray</tt> method as per the specification in |
|
621 |
* {@link Preferences#putByteArray(String,byte[])}. |
|
622 |
* |
|
623 |
* @param key key with which the string form of value is to be associated. |
|
624 |
* @param value value whose string form is to be associated with key. |
|
625 |
* @throws NullPointerException if key or value is <tt>null</tt>. |
|
626 |
* @throws IllegalArgumentException if key.length() exceeds MAX_KEY_LENGTH |
|
627 |
* or if value.length exceeds MAX_VALUE_LENGTH*3/4. |
|
628 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
629 |
* removed with the {@link #removeNode()} method. |
|
630 |
*/ |
|
631 |
public void putByteArray(String key, byte[] value) { |
|
632 |
put(key, Base64.byteArrayToBase64(value)); |
|
633 |
} |
|
634 |
||
635 |
/** |
|
636 |
* Implements the <tt>getByteArray</tt> method as per the specification in |
|
637 |
* {@link Preferences#getByteArray(String,byte[])}. |
|
638 |
* |
|
639 |
* @param key key whose associated value is to be returned as a byte array. |
|
640 |
* @param def the value to be returned in the event that this |
|
641 |
* preference node has no value associated with <tt>key</tt> |
|
642 |
* or the associated value cannot be interpreted as a byte array. |
|
643 |
* @return the byte array value represented by the string associated with |
|
644 |
* <tt>key</tt> in this preference node, or <tt>def</tt> if the |
|
645 |
* associated value does not exist or cannot be interpreted as |
|
646 |
* a byte array. |
|
647 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
648 |
* removed with the {@link #removeNode()} method. |
|
649 |
* @throws NullPointerException if <tt>key</tt> is <tt>null</tt>. (A |
|
650 |
* <tt>null</tt> value for <tt>def</tt> <i>is</i> permitted.) |
|
651 |
*/ |
|
652 |
public byte[] getByteArray(String key, byte[] def) { |
|
653 |
byte[] result = def; |
|
654 |
String value = get(key, null); |
|
655 |
try { |
|
656 |
if (value != null) |
|
657 |
result = Base64.base64ToByteArray(value); |
|
658 |
} |
|
659 |
catch (RuntimeException e) { |
|
660 |
// Ignoring exception causes specified default to be returned |
|
661 |
} |
|
662 |
||
663 |
return result; |
|
664 |
} |
|
665 |
||
666 |
/** |
|
667 |
* Implements the <tt>keys</tt> method as per the specification in |
|
668 |
* {@link Preferences#keys()}. |
|
669 |
* |
|
670 |
* <p>This implementation obtains this preference node's lock, checks that |
|
671 |
* the node has not been removed and invokes {@link #keysSpi()}. |
|
672 |
* |
|
673 |
* @return an array of the keys that have an associated value in this |
|
674 |
* preference node. |
|
675 |
* @throws BackingStoreException if this operation cannot be completed |
|
676 |
* due to a failure in the backing store, or inability to |
|
677 |
* communicate with it. |
|
678 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
679 |
* removed with the {@link #removeNode()} method. |
|
680 |
*/ |
|
681 |
public String[] keys() throws BackingStoreException { |
|
682 |
synchronized(lock) { |
|
683 |
if (removed) |
|
684 |
throw new IllegalStateException("Node has been removed."); |
|
685 |
||
686 |
return keysSpi(); |
|
687 |
} |
|
688 |
} |
|
689 |
||
690 |
/** |
|
691 |
* Implements the <tt>children</tt> method as per the specification in |
|
692 |
* {@link Preferences#childrenNames()}. |
|
693 |
* |
|
694 |
* <p>This implementation obtains this preference node's lock, checks that |
|
695 |
* the node has not been removed, constructs a <tt>TreeSet</tt> initialized |
|
696 |
* to the names of children already cached (the children in this node's |
|
697 |
* "child-cache"), invokes {@link #childrenNamesSpi()}, and adds all of the |
|
698 |
* returned child-names into the set. The elements of the tree set are |
|
699 |
* dumped into a <tt>String</tt> array using the <tt>toArray</tt> method, |
|
700 |
* and this array is returned. |
|
701 |
* |
|
702 |
* @return the names of the children of this preference node. |
|
703 |
* @throws BackingStoreException if this operation cannot be completed |
|
704 |
* due to a failure in the backing store, or inability to |
|
705 |
* communicate with it. |
|
706 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
707 |
* removed with the {@link #removeNode()} method. |
|
708 |
* @see #cachedChildren() |
|
709 |
*/ |
|
710 |
public String[] childrenNames() throws BackingStoreException { |
|
711 |
synchronized(lock) { |
|
712 |
if (removed) |
|
713 |
throw new IllegalStateException("Node has been removed."); |
|
714 |
||
7803
56bc97d69d93
6880112: Project Coin: Port JDK core library code to use diamond operator
smarks
parents:
5506
diff
changeset
|
715 |
Set<String> s = new TreeSet<>(kidCache.keySet()); |
51 | 716 |
for (String kid : childrenNamesSpi()) |
717 |
s.add(kid); |
|
718 |
return s.toArray(EMPTY_STRING_ARRAY); |
|
2 | 719 |
} |
720 |
} |
|
721 |
||
722 |
private static final String[] EMPTY_STRING_ARRAY = new String[0]; |
|
723 |
||
724 |
/** |
|
725 |
* Returns all known unremoved children of this node. |
|
726 |
* |
|
727 |
* @return all known unremoved children of this node. |
|
728 |
*/ |
|
729 |
protected final AbstractPreferences[] cachedChildren() { |
|
51 | 730 |
return kidCache.values().toArray(EMPTY_ABSTRACT_PREFS_ARRAY); |
2 | 731 |
} |
732 |
||
733 |
private static final AbstractPreferences[] EMPTY_ABSTRACT_PREFS_ARRAY |
|
734 |
= new AbstractPreferences[0]; |
|
735 |
||
736 |
/** |
|
737 |
* Implements the <tt>parent</tt> method as per the specification in |
|
738 |
* {@link Preferences#parent()}. |
|
739 |
* |
|
740 |
* <p>This implementation obtains this preference node's lock, checks that |
|
741 |
* the node has not been removed and returns the parent value that was |
|
742 |
* passed to this node's constructor. |
|
743 |
* |
|
744 |
* @return the parent of this preference node. |
|
745 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
746 |
* removed with the {@link #removeNode()} method. |
|
747 |
*/ |
|
748 |
public Preferences parent() { |
|
749 |
synchronized(lock) { |
|
750 |
if (removed) |
|
751 |
throw new IllegalStateException("Node has been removed."); |
|
752 |
||
753 |
return parent; |
|
754 |
} |
|
755 |
} |
|
756 |
||
757 |
/** |
|
758 |
* Implements the <tt>node</tt> method as per the specification in |
|
759 |
* {@link Preferences#node(String)}. |
|
760 |
* |
|
761 |
* <p>This implementation obtains this preference node's lock and checks |
|
762 |
* that the node has not been removed. If <tt>path</tt> is <tt>""</tt>, |
|
763 |
* this node is returned; if <tt>path</tt> is <tt>"/"</tt>, this node's |
|
764 |
* root is returned. If the first character in <tt>path</tt> is |
|
765 |
* not <tt>'/'</tt>, the implementation breaks <tt>path</tt> into |
|
766 |
* tokens and recursively traverses the path from this node to the |
|
767 |
* named node, "consuming" a name and a slash from <tt>path</tt> at |
|
768 |
* each step of the traversal. At each step, the current node is locked |
|
769 |
* and the node's child-cache is checked for the named node. If it is |
|
770 |
* not found, the name is checked to make sure its length does not |
|
771 |
* exceed <tt>MAX_NAME_LENGTH</tt>. Then the {@link #childSpi(String)} |
|
772 |
* method is invoked, and the result stored in this node's child-cache. |
|
773 |
* If the newly created <tt>Preferences</tt> object's {@link #newNode} |
|
774 |
* field is <tt>true</tt> and there are any node change listeners, |
|
775 |
* a notification event is enqueued for processing by the event dispatch |
|
776 |
* thread. |
|
777 |
* |
|
778 |
* <p>When there are no more tokens, the last value found in the |
|
779 |
* child-cache or returned by <tt>childSpi</tt> is returned by this |
|
780 |
* method. If during the traversal, two <tt>"/"</tt> tokens occur |
|
781 |
* consecutively, or the final token is <tt>"/"</tt> (rather than a name), |
|
782 |
* an appropriate <tt>IllegalArgumentException</tt> is thrown. |
|
783 |
* |
|
784 |
* <p> If the first character of <tt>path</tt> is <tt>'/'</tt> |
|
785 |
* (indicating an absolute path name) this preference node's |
|
786 |
* lock is dropped prior to breaking <tt>path</tt> into tokens, and |
|
787 |
* this method recursively traverses the path starting from the root |
|
788 |
* (rather than starting from this node). The traversal is otherwise |
|
789 |
* identical to the one described for relative path names. Dropping |
|
790 |
* the lock on this node prior to commencing the traversal at the root |
|
791 |
* node is essential to avoid the possibility of deadlock, as per the |
|
792 |
* {@link #lock locking invariant}. |
|
793 |
* |
|
794 |
* @param path the path name of the preference node to return. |
|
795 |
* @return the specified preference node. |
|
796 |
* @throws IllegalArgumentException if the path name is invalid (i.e., |
|
797 |
* it contains multiple consecutive slash characters, or ends |
|
798 |
* with a slash character and is more than one character long). |
|
799 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
800 |
* removed with the {@link #removeNode()} method. |
|
801 |
*/ |
|
802 |
public Preferences node(String path) { |
|
803 |
synchronized(lock) { |
|
804 |
if (removed) |
|
805 |
throw new IllegalStateException("Node has been removed."); |
|
806 |
if (path.equals("")) |
|
807 |
return this; |
|
808 |
if (path.equals("/")) |
|
809 |
return root; |
|
810 |
if (path.charAt(0) != '/') |
|
811 |
return node(new StringTokenizer(path, "/", true)); |
|
812 |
} |
|
813 |
||
814 |
// Absolute path. Note that we've dropped our lock to avoid deadlock |
|
815 |
return root.node(new StringTokenizer(path.substring(1), "/", true)); |
|
816 |
} |
|
817 |
||
818 |
/** |
|
819 |
* tokenizer contains <name> {'/' <name>}* |
|
820 |
*/ |
|
821 |
private Preferences node(StringTokenizer path) { |
|
822 |
String token = path.nextToken(); |
|
823 |
if (token.equals("/")) // Check for consecutive slashes |
|
824 |
throw new IllegalArgumentException("Consecutive slashes in path"); |
|
825 |
synchronized(lock) { |
|
51 | 826 |
AbstractPreferences child = kidCache.get(token); |
2 | 827 |
if (child == null) { |
828 |
if (token.length() > MAX_NAME_LENGTH) |
|
829 |
throw new IllegalArgumentException( |
|
830 |
"Node name " + token + " too long"); |
|
831 |
child = childSpi(token); |
|
832 |
if (child.newNode) |
|
833 |
enqueueNodeAddedEvent(child); |
|
834 |
kidCache.put(token, child); |
|
835 |
} |
|
836 |
if (!path.hasMoreTokens()) |
|
837 |
return child; |
|
838 |
path.nextToken(); // Consume slash |
|
839 |
if (!path.hasMoreTokens()) |
|
840 |
throw new IllegalArgumentException("Path ends with slash"); |
|
841 |
return child.node(path); |
|
842 |
} |
|
843 |
} |
|
844 |
||
845 |
/** |
|
846 |
* Implements the <tt>nodeExists</tt> method as per the specification in |
|
847 |
* {@link Preferences#nodeExists(String)}. |
|
848 |
* |
|
849 |
* <p>This implementation is very similar to {@link #node(String)}, |
|
850 |
* except that {@link #getChild(String)} is used instead of {@link |
|
851 |
* #childSpi(String)}. |
|
852 |
* |
|
853 |
* @param path the path name of the node whose existence is to be checked. |
|
854 |
* @return true if the specified node exists. |
|
855 |
* @throws BackingStoreException if this operation cannot be completed |
|
856 |
* due to a failure in the backing store, or inability to |
|
857 |
* communicate with it. |
|
858 |
* @throws IllegalArgumentException if the path name is invalid (i.e., |
|
859 |
* it contains multiple consecutive slash characters, or ends |
|
860 |
* with a slash character and is more than one character long). |
|
861 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
862 |
* removed with the {@link #removeNode()} method and |
|
863 |
* <tt>pathname</tt> is not the empty string (<tt>""</tt>). |
|
864 |
*/ |
|
865 |
public boolean nodeExists(String path) |
|
866 |
throws BackingStoreException |
|
867 |
{ |
|
868 |
synchronized(lock) { |
|
869 |
if (path.equals("")) |
|
870 |
return !removed; |
|
871 |
if (removed) |
|
872 |
throw new IllegalStateException("Node has been removed."); |
|
873 |
if (path.equals("/")) |
|
874 |
return true; |
|
875 |
if (path.charAt(0) != '/') |
|
876 |
return nodeExists(new StringTokenizer(path, "/", true)); |
|
877 |
} |
|
878 |
||
879 |
// Absolute path. Note that we've dropped our lock to avoid deadlock |
|
880 |
return root.nodeExists(new StringTokenizer(path.substring(1), "/", |
|
881 |
true)); |
|
882 |
} |
|
883 |
||
884 |
/** |
|
885 |
* tokenizer contains <name> {'/' <name>}* |
|
886 |
*/ |
|
887 |
private boolean nodeExists(StringTokenizer path) |
|
888 |
throws BackingStoreException |
|
889 |
{ |
|
890 |
String token = path.nextToken(); |
|
891 |
if (token.equals("/")) // Check for consecutive slashes |
|
892 |
throw new IllegalArgumentException("Consecutive slashes in path"); |
|
893 |
synchronized(lock) { |
|
51 | 894 |
AbstractPreferences child = kidCache.get(token); |
2 | 895 |
if (child == null) |
896 |
child = getChild(token); |
|
897 |
if (child==null) |
|
898 |
return false; |
|
899 |
if (!path.hasMoreTokens()) |
|
900 |
return true; |
|
901 |
path.nextToken(); // Consume slash |
|
902 |
if (!path.hasMoreTokens()) |
|
903 |
throw new IllegalArgumentException("Path ends with slash"); |
|
904 |
return child.nodeExists(path); |
|
905 |
} |
|
906 |
} |
|
907 |
||
908 |
/** |
|
909 |
||
910 |
* Implements the <tt>removeNode()</tt> method as per the specification in |
|
911 |
* {@link Preferences#removeNode()}. |
|
912 |
* |
|
913 |
* <p>This implementation checks to see that this node is the root; if so, |
|
914 |
* it throws an appropriate exception. Then, it locks this node's parent, |
|
915 |
* and calls a recursive helper method that traverses the subtree rooted at |
|
916 |
* this node. The recursive method locks the node on which it was called, |
|
917 |
* checks that it has not already been removed, and then ensures that all |
|
918 |
* of its children are cached: The {@link #childrenNamesSpi()} method is |
|
919 |
* invoked and each returned child name is checked for containment in the |
|
920 |
* child-cache. If a child is not already cached, the {@link |
|
921 |
* #childSpi(String)} method is invoked to create a <tt>Preferences</tt> |
|
922 |
* instance for it, and this instance is put into the child-cache. Then |
|
923 |
* the helper method calls itself recursively on each node contained in its |
|
924 |
* child-cache. Next, it invokes {@link #removeNodeSpi()}, marks itself |
|
925 |
* as removed, and removes itself from its parent's child-cache. Finally, |
|
926 |
* if there are any node change listeners, it enqueues a notification |
|
927 |
* event for processing by the event dispatch thread. |
|
928 |
* |
|
929 |
* <p>Note that the helper method is always invoked with all ancestors up |
|
930 |
* to the "closest non-removed ancestor" locked. |
|
931 |
* |
|
932 |
* @throws IllegalStateException if this node (or an ancestor) has already |
|
933 |
* been removed with the {@link #removeNode()} method. |
|
934 |
* @throws UnsupportedOperationException if this method is invoked on |
|
935 |
* the root node. |
|
936 |
* @throws BackingStoreException if this operation cannot be completed |
|
937 |
* due to a failure in the backing store, or inability to |
|
938 |
* communicate with it. |
|
939 |
*/ |
|
940 |
public void removeNode() throws BackingStoreException { |
|
941 |
if (this==root) |
|
942 |
throw new UnsupportedOperationException("Can't remove the root!"); |
|
943 |
synchronized(parent.lock) { |
|
944 |
removeNode2(); |
|
945 |
parent.kidCache.remove(name); |
|
946 |
} |
|
947 |
} |
|
948 |
||
949 |
/* |
|
950 |
* Called with locks on all nodes on path from parent of "removal root" |
|
951 |
* to this (including the former but excluding the latter). |
|
952 |
*/ |
|
953 |
private void removeNode2() throws BackingStoreException { |
|
954 |
synchronized(lock) { |
|
955 |
if (removed) |
|
956 |
throw new IllegalStateException("Node already removed."); |
|
957 |
||
958 |
// Ensure that all children are cached |
|
959 |
String[] kidNames = childrenNamesSpi(); |
|
960 |
for (int i=0; i<kidNames.length; i++) |
|
961 |
if (!kidCache.containsKey(kidNames[i])) |
|
962 |
kidCache.put(kidNames[i], childSpi(kidNames[i])); |
|
963 |
||
964 |
// Recursively remove all cached children |
|
51 | 965 |
for (Iterator<AbstractPreferences> i = kidCache.values().iterator(); |
966 |
i.hasNext();) { |
|
2 | 967 |
try { |
51 | 968 |
i.next().removeNode2(); |
2 | 969 |
i.remove(); |
970 |
} catch (BackingStoreException x) { } |
|
971 |
} |
|
972 |
||
973 |
// Now we have no descendants - it's time to die! |
|
974 |
removeNodeSpi(); |
|
975 |
removed = true; |
|
976 |
parent.enqueueNodeRemovedEvent(this); |
|
977 |
} |
|
978 |
} |
|
979 |
||
980 |
/** |
|
981 |
* Implements the <tt>name</tt> method as per the specification in |
|
982 |
* {@link Preferences#name()}. |
|
983 |
* |
|
984 |
* <p>This implementation merely returns the name that was |
|
985 |
* passed to this node's constructor. |
|
986 |
* |
|
987 |
* @return this preference node's name, relative to its parent. |
|
988 |
*/ |
|
989 |
public String name() { |
|
990 |
return name; |
|
991 |
} |
|
992 |
||
993 |
/** |
|
994 |
* Implements the <tt>absolutePath</tt> method as per the specification in |
|
995 |
* {@link Preferences#absolutePath()}. |
|
996 |
* |
|
997 |
* <p>This implementation merely returns the absolute path name that |
|
998 |
* was computed at the time that this node was constructed (based on |
|
999 |
* the name that was passed to this node's constructor, and the names |
|
1000 |
* that were passed to this node's ancestors' constructors). |
|
1001 |
* |
|
1002 |
* @return this preference node's absolute path name. |
|
1003 |
*/ |
|
1004 |
public String absolutePath() { |
|
1005 |
return absolutePath; |
|
1006 |
} |
|
1007 |
||
1008 |
/** |
|
1009 |
* Implements the <tt>isUserNode</tt> method as per the specification in |
|
1010 |
* {@link Preferences#isUserNode()}. |
|
1011 |
* |
|
1012 |
* <p>This implementation compares this node's root node (which is stored |
|
1013 |
* in a private field) with the value returned by |
|
1014 |
* {@link Preferences#userRoot()}. If the two object references are |
|
1015 |
* identical, this method returns true. |
|
1016 |
* |
|
1017 |
* @return <tt>true</tt> if this preference node is in the user |
|
1018 |
* preference tree, <tt>false</tt> if it's in the system |
|
1019 |
* preference tree. |
|
1020 |
*/ |
|
1021 |
public boolean isUserNode() { |
|
51 | 1022 |
return AccessController.doPrivileged( |
1023 |
new PrivilegedAction<Boolean>() { |
|
1024 |
public Boolean run() { |
|
1025 |
return root == Preferences.userRoot(); |
|
2 | 1026 |
} |
51 | 1027 |
}).booleanValue(); |
2 | 1028 |
} |
1029 |
||
1030 |
public void addPreferenceChangeListener(PreferenceChangeListener pcl) { |
|
1031 |
if (pcl==null) |
|
1032 |
throw new NullPointerException("Change listener is null."); |
|
1033 |
synchronized(lock) { |
|
1034 |
if (removed) |
|
1035 |
throw new IllegalStateException("Node has been removed."); |
|
1036 |
||
1037 |
// Copy-on-write |
|
1038 |
PreferenceChangeListener[] old = prefListeners; |
|
1039 |
prefListeners = new PreferenceChangeListener[old.length + 1]; |
|
1040 |
System.arraycopy(old, 0, prefListeners, 0, old.length); |
|
1041 |
prefListeners[old.length] = pcl; |
|
1042 |
} |
|
1043 |
startEventDispatchThreadIfNecessary(); |
|
1044 |
} |
|
1045 |
||
1046 |
public void removePreferenceChangeListener(PreferenceChangeListener pcl) { |
|
1047 |
synchronized(lock) { |
|
1048 |
if (removed) |
|
1049 |
throw new IllegalStateException("Node has been removed."); |
|
1050 |
if ((prefListeners == null) || (prefListeners.length == 0)) |
|
1051 |
throw new IllegalArgumentException("Listener not registered."); |
|
1052 |
||
1053 |
// Copy-on-write |
|
1054 |
PreferenceChangeListener[] newPl = |
|
1055 |
new PreferenceChangeListener[prefListeners.length - 1]; |
|
1056 |
int i = 0; |
|
1057 |
while (i < newPl.length && prefListeners[i] != pcl) |
|
1058 |
newPl[i] = prefListeners[i++]; |
|
1059 |
||
1060 |
if (i == newPl.length && prefListeners[i] != pcl) |
|
1061 |
throw new IllegalArgumentException("Listener not registered."); |
|
1062 |
while (i < newPl.length) |
|
1063 |
newPl[i] = prefListeners[++i]; |
|
1064 |
prefListeners = newPl; |
|
1065 |
} |
|
1066 |
} |
|
1067 |
||
1068 |
public void addNodeChangeListener(NodeChangeListener ncl) { |
|
1069 |
if (ncl==null) |
|
1070 |
throw new NullPointerException("Change listener is null."); |
|
1071 |
synchronized(lock) { |
|
1072 |
if (removed) |
|
1073 |
throw new IllegalStateException("Node has been removed."); |
|
1074 |
||
1075 |
// Copy-on-write |
|
1076 |
if (nodeListeners == null) { |
|
1077 |
nodeListeners = new NodeChangeListener[1]; |
|
1078 |
nodeListeners[0] = ncl; |
|
1079 |
} else { |
|
1080 |
NodeChangeListener[] old = nodeListeners; |
|
1081 |
nodeListeners = new NodeChangeListener[old.length + 1]; |
|
1082 |
System.arraycopy(old, 0, nodeListeners, 0, old.length); |
|
1083 |
nodeListeners[old.length] = ncl; |
|
1084 |
} |
|
1085 |
} |
|
1086 |
startEventDispatchThreadIfNecessary(); |
|
1087 |
} |
|
1088 |
||
1089 |
public void removeNodeChangeListener(NodeChangeListener ncl) { |
|
1090 |
synchronized(lock) { |
|
1091 |
if (removed) |
|
1092 |
throw new IllegalStateException("Node has been removed."); |
|
1093 |
if ((nodeListeners == null) || (nodeListeners.length == 0)) |
|
1094 |
throw new IllegalArgumentException("Listener not registered."); |
|
1095 |
||
1096 |
// Copy-on-write |
|
1097 |
int i = 0; |
|
1098 |
while (i < nodeListeners.length && nodeListeners[i] != ncl) |
|
1099 |
i++; |
|
1100 |
if (i == nodeListeners.length) |
|
1101 |
throw new IllegalArgumentException("Listener not registered."); |
|
1102 |
NodeChangeListener[] newNl = |
|
1103 |
new NodeChangeListener[nodeListeners.length - 1]; |
|
1104 |
if (i != 0) |
|
1105 |
System.arraycopy(nodeListeners, 0, newNl, 0, i); |
|
1106 |
if (i != newNl.length) |
|
1107 |
System.arraycopy(nodeListeners, i + 1, |
|
1108 |
newNl, i, newNl.length - i); |
|
1109 |
nodeListeners = newNl; |
|
1110 |
} |
|
1111 |
} |
|
1112 |
||
1113 |
// "SPI" METHODS |
|
1114 |
||
1115 |
/** |
|
1116 |
* Put the given key-value association into this preference node. It is |
|
1117 |
* guaranteed that <tt>key</tt> and <tt>value</tt> are non-null and of |
|
1118 |
* legal length. Also, it is guaranteed that this node has not been |
|
1119 |
* removed. (The implementor needn't check for any of these things.) |
|
1120 |
* |
|
1121 |
* <p>This method is invoked with the lock on this node held. |
|
1122 |
*/ |
|
1123 |
protected abstract void putSpi(String key, String value); |
|
1124 |
||
1125 |
/** |
|
1126 |
* Return the value associated with the specified key at this preference |
|
1127 |
* node, or <tt>null</tt> if there is no association for this key, or the |
|
1128 |
* association cannot be determined at this time. It is guaranteed that |
|
1129 |
* <tt>key</tt> is non-null. Also, it is guaranteed that this node has |
|
1130 |
* not been removed. (The implementor needn't check for either of these |
|
1131 |
* things.) |
|
1132 |
* |
|
1133 |
* <p> Generally speaking, this method should not throw an exception |
|
1134 |
* under any circumstances. If, however, if it does throw an exception, |
|
1135 |
* the exception will be intercepted and treated as a <tt>null</tt> |
|
1136 |
* return value. |
|
1137 |
* |
|
1138 |
* <p>This method is invoked with the lock on this node held. |
|
1139 |
* |
|
1140 |
* @return the value associated with the specified key at this preference |
|
1141 |
* node, or <tt>null</tt> if there is no association for this |
|
1142 |
* key, or the association cannot be determined at this time. |
|
1143 |
*/ |
|
1144 |
protected abstract String getSpi(String key); |
|
1145 |
||
1146 |
/** |
|
1147 |
* Remove the association (if any) for the specified key at this |
|
1148 |
* preference node. It is guaranteed that <tt>key</tt> is non-null. |
|
1149 |
* Also, it is guaranteed that this node has not been removed. |
|
1150 |
* (The implementor needn't check for either of these things.) |
|
1151 |
* |
|
1152 |
* <p>This method is invoked with the lock on this node held. |
|
1153 |
*/ |
|
1154 |
protected abstract void removeSpi(String key); |
|
1155 |
||
1156 |
/** |
|
1157 |
* Removes this preference node, invalidating it and any preferences that |
|
1158 |
* it contains. The named child will have no descendants at the time this |
|
1159 |
* invocation is made (i.e., the {@link Preferences#removeNode()} method |
|
1160 |
* invokes this method repeatedly in a bottom-up fashion, removing each of |
|
1161 |
* a node's descendants before removing the node itself). |
|
1162 |
* |
|
1163 |
* <p>This method is invoked with the lock held on this node and its |
|
1164 |
* parent (and all ancestors that are being removed as a |
|
1165 |
* result of a single invocation to {@link Preferences#removeNode()}). |
|
1166 |
* |
|
1167 |
* <p>The removal of a node needn't become persistent until the |
|
1168 |
* <tt>flush</tt> method is invoked on this node (or an ancestor). |
|
1169 |
* |
|
1170 |
* <p>If this node throws a <tt>BackingStoreException</tt>, the exception |
|
1171 |
* will propagate out beyond the enclosing {@link #removeNode()} |
|
1172 |
* invocation. |
|
1173 |
* |
|
1174 |
* @throws BackingStoreException if this operation cannot be completed |
|
1175 |
* due to a failure in the backing store, or inability to |
|
1176 |
* communicate with it. |
|
1177 |
*/ |
|
1178 |
protected abstract void removeNodeSpi() throws BackingStoreException; |
|
1179 |
||
1180 |
/** |
|
1181 |
* Returns all of the keys that have an associated value in this |
|
1182 |
* preference node. (The returned array will be of size zero if |
|
1183 |
* this node has no preferences.) It is guaranteed that this node has not |
|
1184 |
* been removed. |
|
1185 |
* |
|
1186 |
* <p>This method is invoked with the lock on this node held. |
|
1187 |
* |
|
1188 |
* <p>If this node throws a <tt>BackingStoreException</tt>, the exception |
|
1189 |
* will propagate out beyond the enclosing {@link #keys()} invocation. |
|
1190 |
* |
|
1191 |
* @return an array of the keys that have an associated value in this |
|
1192 |
* preference node. |
|
1193 |
* @throws BackingStoreException if this operation cannot be completed |
|
1194 |
* due to a failure in the backing store, or inability to |
|
1195 |
* communicate with it. |
|
1196 |
*/ |
|
1197 |
protected abstract String[] keysSpi() throws BackingStoreException; |
|
1198 |
||
1199 |
/** |
|
1200 |
* Returns the names of the children of this preference node. (The |
|
1201 |
* returned array will be of size zero if this node has no children.) |
|
1202 |
* This method need not return the names of any nodes already cached, |
|
1203 |
* but may do so without harm. |
|
1204 |
* |
|
1205 |
* <p>This method is invoked with the lock on this node held. |
|
1206 |
* |
|
1207 |
* <p>If this node throws a <tt>BackingStoreException</tt>, the exception |
|
1208 |
* will propagate out beyond the enclosing {@link #childrenNames()} |
|
1209 |
* invocation. |
|
1210 |
* |
|
1211 |
* @return an array containing the names of the children of this |
|
1212 |
* preference node. |
|
1213 |
* @throws BackingStoreException if this operation cannot be completed |
|
1214 |
* due to a failure in the backing store, or inability to |
|
1215 |
* communicate with it. |
|
1216 |
*/ |
|
1217 |
protected abstract String[] childrenNamesSpi() |
|
1218 |
throws BackingStoreException; |
|
1219 |
||
1220 |
/** |
|
1221 |
* Returns the named child if it exists, or <tt>null</tt> if it does not. |
|
1222 |
* It is guaranteed that <tt>nodeName</tt> is non-null, non-empty, |
|
1223 |
* does not contain the slash character ('/'), and is no longer than |
|
1224 |
* {@link #MAX_NAME_LENGTH} characters. Also, it is guaranteed |
|
1225 |
* that this node has not been removed. (The implementor needn't check |
|
1226 |
* for any of these things if he chooses to override this method.) |
|
1227 |
* |
|
1228 |
* <p>Finally, it is guaranteed that the named node has not been returned |
|
1229 |
* by a previous invocation of this method or {@link #childSpi} after the |
|
1230 |
* last time that it was removed. In other words, a cached value will |
|
1231 |
* always be used in preference to invoking this method. (The implementor |
|
1232 |
* needn't maintain his own cache of previously returned children if he |
|
1233 |
* chooses to override this method.) |
|
1234 |
* |
|
1235 |
* <p>This implementation obtains this preference node's lock, invokes |
|
1236 |
* {@link #childrenNames()} to get an array of the names of this node's |
|
1237 |
* children, and iterates over the array comparing the name of each child |
|
1238 |
* with the specified node name. If a child node has the correct name, |
|
1239 |
* the {@link #childSpi(String)} method is invoked and the resulting |
|
1240 |
* node is returned. If the iteration completes without finding the |
|
1241 |
* specified name, <tt>null</tt> is returned. |
|
1242 |
* |
|
1243 |
* @param nodeName name of the child to be searched for. |
|
1244 |
* @return the named child if it exists, or null if it does not. |
|
1245 |
* @throws BackingStoreException if this operation cannot be completed |
|
1246 |
* due to a failure in the backing store, or inability to |
|
1247 |
* communicate with it. |
|
1248 |
*/ |
|
1249 |
protected AbstractPreferences getChild(String nodeName) |
|
1250 |
throws BackingStoreException { |
|
1251 |
synchronized(lock) { |
|
1252 |
// assert kidCache.get(nodeName)==null; |
|
1253 |
String[] kidNames = childrenNames(); |
|
1254 |
for (int i=0; i<kidNames.length; i++) |
|
1255 |
if (kidNames[i].equals(nodeName)) |
|
1256 |
return childSpi(kidNames[i]); |
|
1257 |
} |
|
1258 |
return null; |
|
1259 |
} |
|
1260 |
||
1261 |
/** |
|
1262 |
* Returns the named child of this preference node, creating it if it does |
|
1263 |
* not already exist. It is guaranteed that <tt>name</tt> is non-null, |
|
1264 |
* non-empty, does not contain the slash character ('/'), and is no longer |
|
1265 |
* than {@link #MAX_NAME_LENGTH} characters. Also, it is guaranteed that |
|
1266 |
* this node has not been removed. (The implementor needn't check for any |
|
1267 |
* of these things.) |
|
1268 |
* |
|
1269 |
* <p>Finally, it is guaranteed that the named node has not been returned |
|
1270 |
* by a previous invocation of this method or {@link #getChild(String)} |
|
1271 |
* after the last time that it was removed. In other words, a cached |
|
1272 |
* value will always be used in preference to invoking this method. |
|
1273 |
* Subclasses need not maintain their own cache of previously returned |
|
1274 |
* children. |
|
1275 |
* |
|
1276 |
* <p>The implementer must ensure that the returned node has not been |
|
1277 |
* removed. If a like-named child of this node was previously removed, the |
|
1278 |
* implementer must return a newly constructed <tt>AbstractPreferences</tt> |
|
1279 |
* node; once removed, an <tt>AbstractPreferences</tt> node |
|
1280 |
* cannot be "resuscitated." |
|
1281 |
* |
|
1282 |
* <p>If this method causes a node to be created, this node is not |
|
1283 |
* guaranteed to be persistent until the <tt>flush</tt> method is |
|
1284 |
* invoked on this node or one of its ancestors (or descendants). |
|
1285 |
* |
|
1286 |
* <p>This method is invoked with the lock on this node held. |
|
1287 |
* |
|
1288 |
* @param name The name of the child node to return, relative to |
|
1289 |
* this preference node. |
|
1290 |
* @return The named child node. |
|
1291 |
*/ |
|
1292 |
protected abstract AbstractPreferences childSpi(String name); |
|
1293 |
||
1294 |
/** |
|
1295 |
* Returns the absolute path name of this preferences node. |
|
1296 |
*/ |
|
1297 |
public String toString() { |
|
1298 |
return (this.isUserNode() ? "User" : "System") + |
|
1299 |
" Preference Node: " + this.absolutePath(); |
|
1300 |
} |
|
1301 |
||
1302 |
/** |
|
1303 |
* Implements the <tt>sync</tt> method as per the specification in |
|
1304 |
* {@link Preferences#sync()}. |
|
1305 |
* |
|
1306 |
* <p>This implementation calls a recursive helper method that locks this |
|
1307 |
* node, invokes syncSpi() on it, unlocks this node, and recursively |
|
1308 |
* invokes this method on each "cached child." A cached child is a child |
|
1309 |
* of this node that has been created in this VM and not subsequently |
|
1310 |
* removed. In effect, this method does a depth first traversal of the |
|
1311 |
* "cached subtree" rooted at this node, calling syncSpi() on each node in |
|
1312 |
* the subTree while only that node is locked. Note that syncSpi() is |
|
1313 |
* invoked top-down. |
|
1314 |
* |
|
1315 |
* @throws BackingStoreException if this operation cannot be completed |
|
1316 |
* due to a failure in the backing store, or inability to |
|
1317 |
* communicate with it. |
|
1318 |
* @throws IllegalStateException if this node (or an ancestor) has been |
|
1319 |
* removed with the {@link #removeNode()} method. |
|
1320 |
* @see #flush() |
|
1321 |
*/ |
|
1322 |
public void sync() throws BackingStoreException { |
|
1323 |
sync2(); |
|
1324 |
} |
|
1325 |
||
1326 |
private void sync2() throws BackingStoreException { |
|
1327 |
AbstractPreferences[] cachedKids; |
|
1328 |
||
1329 |
synchronized(lock) { |
|
1330 |
if (removed) |
|
1331 |
throw new IllegalStateException("Node has been removed"); |
|
1332 |
syncSpi(); |
|
1333 |
cachedKids = cachedChildren(); |
|
1334 |
} |
|
1335 |
||
1336 |
for (int i=0; i<cachedKids.length; i++) |
|
1337 |
cachedKids[i].sync2(); |
|
1338 |
} |
|
1339 |
||
1340 |
/** |
|
1341 |
* This method is invoked with this node locked. The contract of this |
|
1342 |
* method is to synchronize any cached preferences stored at this node |
|
1343 |
* with any stored in the backing store. (It is perfectly possible that |
|
1344 |
* this node does not exist on the backing store, either because it has |
|
1345 |
* been deleted by another VM, or because it has not yet been created.) |
|
1346 |
* Note that this method should <i>not</i> synchronize the preferences in |
|
1347 |
* any subnodes of this node. If the backing store naturally syncs an |
|
1348 |
* entire subtree at once, the implementer is encouraged to override |
|
1349 |
* sync(), rather than merely overriding this method. |
|
1350 |
* |
|
1351 |
* <p>If this node throws a <tt>BackingStoreException</tt>, the exception |
|
1352 |
* will propagate out beyond the enclosing {@link #sync()} invocation. |
|
1353 |
* |
|
1354 |
* @throws BackingStoreException if this operation cannot be completed |
|
1355 |
* due to a failure in the backing store, or inability to |
|
1356 |
* communicate with it. |
|
1357 |
*/ |
|
1358 |
protected abstract void syncSpi() throws BackingStoreException; |
|
1359 |
||
1360 |
/** |
|
1361 |
* Implements the <tt>flush</tt> method as per the specification in |
|
1362 |
* {@link Preferences#flush()}. |
|
1363 |
* |
|
1364 |
* <p>This implementation calls a recursive helper method that locks this |
|
1365 |
* node, invokes flushSpi() on it, unlocks this node, and recursively |
|
1366 |
* invokes this method on each "cached child." A cached child is a child |
|
1367 |
* of this node that has been created in this VM and not subsequently |
|
1368 |
* removed. In effect, this method does a depth first traversal of the |
|
1369 |
* "cached subtree" rooted at this node, calling flushSpi() on each node in |
|
1370 |
* the subTree while only that node is locked. Note that flushSpi() is |
|
1371 |
* invoked top-down. |
|
1372 |
* |
|
1373 |
* <p> If this method is invoked on a node that has been removed with |
|
1374 |
* the {@link #removeNode()} method, flushSpi() is invoked on this node, |
|
1375 |
* but not on others. |
|
1376 |
* |
|
1377 |
* @throws BackingStoreException if this operation cannot be completed |
|
1378 |
* due to a failure in the backing store, or inability to |
|
1379 |
* communicate with it. |
|
1380 |
* @see #flush() |
|
1381 |
*/ |
|
1382 |
public void flush() throws BackingStoreException { |
|
1383 |
flush2(); |
|
1384 |
} |
|
1385 |
||
1386 |
private void flush2() throws BackingStoreException { |
|
1387 |
AbstractPreferences[] cachedKids; |
|
1388 |
||
1389 |
synchronized(lock) { |
|
1390 |
flushSpi(); |
|
1391 |
if(removed) |
|
1392 |
return; |
|
1393 |
cachedKids = cachedChildren(); |
|
1394 |
} |
|
1395 |
||
1396 |
for (int i = 0; i < cachedKids.length; i++) |
|
1397 |
cachedKids[i].flush2(); |
|
1398 |
} |
|
1399 |
||
1400 |
/** |
|
1401 |
* This method is invoked with this node locked. The contract of this |
|
1402 |
* method is to force any cached changes in the contents of this |
|
1403 |
* preference node to the backing store, guaranteeing their persistence. |
|
1404 |
* (It is perfectly possible that this node does not exist on the backing |
|
1405 |
* store, either because it has been deleted by another VM, or because it |
|
1406 |
* has not yet been created.) Note that this method should <i>not</i> |
|
1407 |
* flush the preferences in any subnodes of this node. If the backing |
|
1408 |
* store naturally flushes an entire subtree at once, the implementer is |
|
1409 |
* encouraged to override flush(), rather than merely overriding this |
|
1410 |
* method. |
|
1411 |
* |
|
1412 |
* <p>If this node throws a <tt>BackingStoreException</tt>, the exception |
|
1413 |
* will propagate out beyond the enclosing {@link #flush()} invocation. |
|
1414 |
* |
|
1415 |
* @throws BackingStoreException if this operation cannot be completed |
|
1416 |
* due to a failure in the backing store, or inability to |
|
1417 |
* communicate with it. |
|
1418 |
*/ |
|
1419 |
protected abstract void flushSpi() throws BackingStoreException; |
|
1420 |
||
1421 |
/** |
|
1422 |
* Returns <tt>true</tt> iff this node (or an ancestor) has been |
|
1423 |
* removed with the {@link #removeNode()} method. This method |
|
1424 |
* locks this node prior to returning the contents of the private |
|
1425 |
* field used to track this state. |
|
1426 |
* |
|
1427 |
* @return <tt>true</tt> iff this node (or an ancestor) has been |
|
1428 |
* removed with the {@link #removeNode()} method. |
|
1429 |
*/ |
|
1430 |
protected boolean isRemoved() { |
|
1431 |
synchronized(lock) { |
|
1432 |
return removed; |
|
1433 |
} |
|
1434 |
} |
|
1435 |
||
1436 |
/** |
|
1437 |
* Queue of pending notification events. When a preference or node |
|
1438 |
* change event for which there are one or more listeners occurs, |
|
1439 |
* it is placed on this queue and the queue is notified. A background |
|
1440 |
* thread waits on this queue and delivers the events. This decouples |
|
1441 |
* event delivery from preference activity, greatly simplifying |
|
1442 |
* locking and reducing opportunity for deadlock. |
|
1443 |
*/ |
|
7803
56bc97d69d93
6880112: Project Coin: Port JDK core library code to use diamond operator
smarks
parents:
5506
diff
changeset
|
1444 |
private static final List<EventObject> eventQueue = new LinkedList<>(); |
2 | 1445 |
|
1446 |
/** |
|
1447 |
* These two classes are used to distinguish NodeChangeEvents on |
|
1448 |
* eventQueue so the event dispatch thread knows whether to call |
|
1449 |
* childAdded or childRemoved. |
|
1450 |
*/ |
|
1451 |
private class NodeAddedEvent extends NodeChangeEvent { |
|
1452 |
private static final long serialVersionUID = -6743557530157328528L; |
|
1453 |
NodeAddedEvent(Preferences parent, Preferences child) { |
|
1454 |
super(parent, child); |
|
1455 |
} |
|
1456 |
} |
|
1457 |
private class NodeRemovedEvent extends NodeChangeEvent { |
|
1458 |
private static final long serialVersionUID = 8735497392918824837L; |
|
1459 |
NodeRemovedEvent(Preferences parent, Preferences child) { |
|
1460 |
super(parent, child); |
|
1461 |
} |
|
1462 |
} |
|
1463 |
||
1464 |
/** |
|
1465 |
* A single background thread ("the event notification thread") monitors |
|
1466 |
* the event queue and delivers events that are placed on the queue. |
|
1467 |
*/ |
|
1468 |
private static class EventDispatchThread extends Thread { |
|
1469 |
public void run() { |
|
1470 |
while(true) { |
|
1471 |
// Wait on eventQueue till an event is present |
|
1472 |
EventObject event = null; |
|
1473 |
synchronized(eventQueue) { |
|
1474 |
try { |
|
1475 |
while (eventQueue.isEmpty()) |
|
1476 |
eventQueue.wait(); |
|
51 | 1477 |
event = eventQueue.remove(0); |
2 | 1478 |
} catch (InterruptedException e) { |
1479 |
// XXX Log "Event dispatch thread interrupted. Exiting" |
|
1480 |
return; |
|
1481 |
} |
|
1482 |
} |
|
1483 |
||
1484 |
// Now we have event & hold no locks; deliver evt to listeners |
|
1485 |
AbstractPreferences src=(AbstractPreferences)event.getSource(); |
|
1486 |
if (event instanceof PreferenceChangeEvent) { |
|
1487 |
PreferenceChangeEvent pce = (PreferenceChangeEvent)event; |
|
1488 |
PreferenceChangeListener[] listeners = src.prefListeners(); |
|
1489 |
for (int i=0; i<listeners.length; i++) |
|
1490 |
listeners[i].preferenceChange(pce); |
|
1491 |
} else { |
|
1492 |
NodeChangeEvent nce = (NodeChangeEvent)event; |
|
1493 |
NodeChangeListener[] listeners = src.nodeListeners(); |
|
1494 |
if (nce instanceof NodeAddedEvent) { |
|
1495 |
for (int i=0; i<listeners.length; i++) |
|
1496 |
listeners[i].childAdded(nce); |
|
1497 |
} else { |
|
1498 |
// assert nce instanceof NodeRemovedEvent; |
|
1499 |
for (int i=0; i<listeners.length; i++) |
|
1500 |
listeners[i].childRemoved(nce); |
|
1501 |
} |
|
1502 |
} |
|
1503 |
} |
|
1504 |
} |
|
1505 |
} |
|
1506 |
||
1507 |
private static Thread eventDispatchThread = null; |
|
1508 |
||
1509 |
/** |
|
1510 |
* This method starts the event dispatch thread the first time it |
|
1511 |
* is called. The event dispatch thread will be started only |
|
1512 |
* if someone registers a listener. |
|
1513 |
*/ |
|
1514 |
private static synchronized void startEventDispatchThreadIfNecessary() { |
|
1515 |
if (eventDispatchThread == null) { |
|
1516 |
// XXX Log "Starting event dispatch thread" |
|
1517 |
eventDispatchThread = new EventDispatchThread(); |
|
1518 |
eventDispatchThread.setDaemon(true); |
|
1519 |
eventDispatchThread.start(); |
|
1520 |
} |
|
1521 |
} |
|
1522 |
||
1523 |
/** |
|
1524 |
* Return this node's preference/node change listeners. Even though |
|
1525 |
* we're using a copy-on-write lists, we use synchronized accessors to |
|
1526 |
* ensure information transmission from the writing thread to the |
|
1527 |
* reading thread. |
|
1528 |
*/ |
|
1529 |
PreferenceChangeListener[] prefListeners() { |
|
1530 |
synchronized(lock) { |
|
1531 |
return prefListeners; |
|
1532 |
} |
|
1533 |
} |
|
1534 |
NodeChangeListener[] nodeListeners() { |
|
1535 |
synchronized(lock) { |
|
1536 |
return nodeListeners; |
|
1537 |
} |
|
1538 |
} |
|
1539 |
||
1540 |
/** |
|
1541 |
* Enqueue a preference change event for delivery to registered |
|
1542 |
* preference change listeners unless there are no registered |
|
1543 |
* listeners. Invoked with this.lock held. |
|
1544 |
*/ |
|
1545 |
private void enqueuePreferenceChangeEvent(String key, String newValue) { |
|
1546 |
if (prefListeners.length != 0) { |
|
1547 |
synchronized(eventQueue) { |
|
1548 |
eventQueue.add(new PreferenceChangeEvent(this, key, newValue)); |
|
1549 |
eventQueue.notify(); |
|
1550 |
} |
|
1551 |
} |
|
1552 |
} |
|
1553 |
||
1554 |
/** |
|
1555 |
* Enqueue a "node added" event for delivery to registered node change |
|
1556 |
* listeners unless there are no registered listeners. Invoked with |
|
1557 |
* this.lock held. |
|
1558 |
*/ |
|
1559 |
private void enqueueNodeAddedEvent(Preferences child) { |
|
1560 |
if (nodeListeners.length != 0) { |
|
1561 |
synchronized(eventQueue) { |
|
1562 |
eventQueue.add(new NodeAddedEvent(this, child)); |
|
1563 |
eventQueue.notify(); |
|
1564 |
} |
|
1565 |
} |
|
1566 |
} |
|
1567 |
||
1568 |
/** |
|
1569 |
* Enqueue a "node removed" event for delivery to registered node change |
|
1570 |
* listeners unless there are no registered listeners. Invoked with |
|
1571 |
* this.lock held. |
|
1572 |
*/ |
|
1573 |
private void enqueueNodeRemovedEvent(Preferences child) { |
|
1574 |
if (nodeListeners.length != 0) { |
|
1575 |
synchronized(eventQueue) { |
|
1576 |
eventQueue.add(new NodeRemovedEvent(this, child)); |
|
1577 |
eventQueue.notify(); |
|
1578 |
} |
|
1579 |
} |
|
1580 |
} |
|
1581 |
||
1582 |
/** |
|
1583 |
* Implements the <tt>exportNode</tt> method as per the specification in |
|
1584 |
* {@link Preferences#exportNode(OutputStream)}. |
|
1585 |
* |
|
1586 |
* @param os the output stream on which to emit the XML document. |
|
1587 |
* @throws IOException if writing to the specified output stream |
|
1588 |
* results in an <tt>IOException</tt>. |
|
1589 |
* @throws BackingStoreException if preference data cannot be read from |
|
1590 |
* backing store. |
|
1591 |
*/ |
|
1592 |
public void exportNode(OutputStream os) |
|
1593 |
throws IOException, BackingStoreException |
|
1594 |
{ |
|
1595 |
XmlSupport.export(os, this, false); |
|
1596 |
} |
|
1597 |
||
1598 |
/** |
|
1599 |
* Implements the <tt>exportSubtree</tt> method as per the specification in |
|
1600 |
* {@link Preferences#exportSubtree(OutputStream)}. |
|
1601 |
* |
|
1602 |
* @param os the output stream on which to emit the XML document. |
|
1603 |
* @throws IOException if writing to the specified output stream |
|
1604 |
* results in an <tt>IOException</tt>. |
|
1605 |
* @throws BackingStoreException if preference data cannot be read from |
|
1606 |
* backing store. |
|
1607 |
*/ |
|
1608 |
public void exportSubtree(OutputStream os) |
|
1609 |
throws IOException, BackingStoreException |
|
1610 |
{ |
|
1611 |
XmlSupport.export(os, this, true); |
|
1612 |
} |
|
1613 |
} |