src/java.activation/share/classes/javax/activation/CommandMap.java
changeset 47216 71c04702a3d5
parent 30006 34db9a7db620
equal deleted inserted replaced
47215:4ebc2e2fb97c 47216:71c04702a3d5
       
     1 /*
       
     2  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
       
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       
     4  *
       
     5  * This code is free software; you can redistribute it and/or modify it
       
     6  * under the terms of the GNU General Public License version 2 only, as
       
     7  * published by the Free Software Foundation.  Oracle designates this
       
     8  * particular file as subject to the "Classpath" exception as provided
       
     9  * by Oracle in the LICENSE file that accompanied this code.
       
    10  *
       
    11  * This code is distributed in the hope that it will be useful, but WITHOUT
       
    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
       
    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
       
    14  * version 2 for more details (a copy is included in the LICENSE file that
       
    15  * accompanied this code).
       
    16  *
       
    17  * You should have received a copy of the GNU General Public License version
       
    18  * 2 along with this work; if not, write to the Free Software Foundation,
       
    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
       
    20  *
       
    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
       
    22  * or visit www.oracle.com if you need additional information or have any
       
    23  * questions.
       
    24  */
       
    25 
       
    26 package javax.activation;
       
    27 
       
    28 import java.util.Map;
       
    29 import java.util.WeakHashMap;
       
    30 
       
    31 
       
    32 /**
       
    33  * The CommandMap class provides an interface to a registry of
       
    34  * command objects available in the system.
       
    35  * Developers are expected to either use the CommandMap
       
    36  * implementation included with this package (MailcapCommandMap) or
       
    37  * develop their own. Note that some of the methods in this class are
       
    38  * abstract.
       
    39  *
       
    40  * @since 1.6
       
    41  */
       
    42 public abstract class CommandMap {
       
    43     private static CommandMap defaultCommandMap = null;
       
    44     private static Map<ClassLoader,CommandMap> map =
       
    45                                 new WeakHashMap<ClassLoader,CommandMap>();
       
    46 
       
    47     /**
       
    48      * Get the default CommandMap.
       
    49      *
       
    50      * <ul>
       
    51      * <li> In cases where a CommandMap instance has been previously set
       
    52      *      to some value (via <i>setDefaultCommandMap</i>)
       
    53      *  return the CommandMap.
       
    54      * <li>
       
    55      *  In cases where no CommandMap has been set, the CommandMap
       
    56      *       creates an instance of {@code MailcapCommandMap} and
       
    57      *       set that to the default, returning its value.
       
    58      *
       
    59      * </ul>
       
    60      *
       
    61      * @return the CommandMap
       
    62      */
       
    63     public static synchronized CommandMap getDefaultCommandMap() {
       
    64         if (defaultCommandMap != null)
       
    65             return defaultCommandMap;
       
    66 
       
    67         // fetch per-thread-context-class-loader default
       
    68         ClassLoader tccl = SecuritySupport.getContextClassLoader();
       
    69         CommandMap def = map.get(tccl);
       
    70         if (def == null) {
       
    71             def = new MailcapCommandMap();
       
    72             map.put(tccl, def);
       
    73         }
       
    74         return def;
       
    75     }
       
    76 
       
    77     /**
       
    78      * Set the default CommandMap. Reset the CommandMap to the default by
       
    79      * calling this method with {@code null}.
       
    80      *
       
    81      * @param commandMap The new default CommandMap.
       
    82      * @exception SecurityException if the caller doesn't have permission
       
    83      *                                  to change the default
       
    84      */
       
    85     public static synchronized void setDefaultCommandMap(CommandMap commandMap) {
       
    86         SecurityManager security = System.getSecurityManager();
       
    87         if (security != null) {
       
    88             try {
       
    89                 // if it's ok with the SecurityManager, it's ok with me...
       
    90                 security.checkSetFactory();
       
    91             } catch (SecurityException ex) {
       
    92                 // otherwise, we also allow it if this code and the
       
    93                 // factory come from the same (non-system) class loader (e.g.,
       
    94                 // the JAF classes were loaded with the applet classes).
       
    95                 ClassLoader cl = CommandMap.class.getClassLoader();
       
    96                 if (cl == null || cl.getParent() == null ||
       
    97                     cl != commandMap.getClass().getClassLoader()) {
       
    98                     throw ex;
       
    99                 }
       
   100             }
       
   101         }
       
   102         // remove any per-thread-context-class-loader CommandMap
       
   103         map.remove(SecuritySupport.getContextClassLoader());
       
   104         defaultCommandMap = commandMap;
       
   105     }
       
   106 
       
   107     /**
       
   108      * Get the preferred command list from a MIME Type. The actual semantics
       
   109      * are determined by the implementation of the CommandMap.
       
   110      *
       
   111      * @param mimeType  the MIME type
       
   112      * @return the CommandInfo classes that represent the command Beans.
       
   113      */
       
   114     abstract public  CommandInfo[] getPreferredCommands(String mimeType);
       
   115 
       
   116     /**
       
   117      * Get the preferred command list from a MIME Type. The actual semantics
       
   118      * are determined by the implementation of the CommandMap. <p>
       
   119      *
       
   120      * The {@code DataSource} provides extra information, such as
       
   121      * the file name, that a CommandMap implementation may use to further
       
   122      * refine the list of commands that are returned.  The implementation
       
   123      * in this class simply calls the {@code getPreferredCommands}
       
   124      * method that ignores this argument.
       
   125      *
       
   126      * @param mimeType  the MIME type
       
   127      * @param ds        a DataSource for the data
       
   128      * @return the CommandInfo classes that represent the command Beans.
       
   129      * @since   1.6, JAF 1.1
       
   130      */
       
   131     public CommandInfo[] getPreferredCommands(String mimeType, DataSource ds) {
       
   132         return getPreferredCommands(mimeType);
       
   133     }
       
   134 
       
   135     /**
       
   136      * Get all the available commands for this type. This method
       
   137      * should return all the possible commands for this MIME type.
       
   138      *
       
   139      * @param mimeType  the MIME type
       
   140      * @return the CommandInfo objects representing all the commands.
       
   141      */
       
   142     abstract public CommandInfo[] getAllCommands(String mimeType);
       
   143 
       
   144     /**
       
   145      * Get all the available commands for this type. This method
       
   146      * should return all the possible commands for this MIME type. <p>
       
   147      *
       
   148      * The {@code DataSource} provides extra information, such as
       
   149      * the file name, that a CommandMap implementation may use to further
       
   150      * refine the list of commands that are returned.  The implementation
       
   151      * in this class simply calls the {@code getAllCommands}
       
   152      * method that ignores this argument.
       
   153      *
       
   154      * @param mimeType  the MIME type
       
   155      * @param ds        a DataSource for the data
       
   156      * @return the CommandInfo objects representing all the commands.
       
   157      * @since   1.6, JAF 1.1
       
   158      */
       
   159     public CommandInfo[] getAllCommands(String mimeType, DataSource ds) {
       
   160         return getAllCommands(mimeType);
       
   161     }
       
   162 
       
   163     /**
       
   164      * Get the default command corresponding to the MIME type.
       
   165      *
       
   166      * @param mimeType  the MIME type
       
   167      * @param cmdName   the command name
       
   168      * @return the CommandInfo corresponding to the command.
       
   169      */
       
   170     abstract public CommandInfo getCommand(String mimeType, String cmdName);
       
   171 
       
   172     /**
       
   173      * Get the default command corresponding to the MIME type. <p>
       
   174      *
       
   175      * The {@code DataSource} provides extra information, such as
       
   176      * the file name, that a CommandMap implementation may use to further
       
   177      * refine the command that is chosen.  The implementation
       
   178      * in this class simply calls the {@code getCommand}
       
   179      * method that ignores this argument.
       
   180      *
       
   181      * @param mimeType  the MIME type
       
   182      * @param cmdName   the command name
       
   183      * @param ds        a DataSource for the data
       
   184      * @return the CommandInfo corresponding to the command.
       
   185      * @since   1.6, JAF 1.1
       
   186      */
       
   187     public CommandInfo getCommand(String mimeType, String cmdName,
       
   188                                 DataSource ds) {
       
   189         return getCommand(mimeType, cmdName);
       
   190     }
       
   191 
       
   192     /**
       
   193      * Locate a DataContentHandler that corresponds to the MIME type.
       
   194      * The mechanism and semantics for determining this are determined
       
   195      * by the implementation of the particular CommandMap.
       
   196      *
       
   197      * @param mimeType  the MIME type
       
   198      * @return          the DataContentHandler for the MIME type
       
   199      */
       
   200     abstract public DataContentHandler createDataContentHandler(String
       
   201                                                                 mimeType);
       
   202 
       
   203     /**
       
   204      * Locate a DataContentHandler that corresponds to the MIME type.
       
   205      * The mechanism and semantics for determining this are determined
       
   206      * by the implementation of the particular CommandMap. <p>
       
   207      *
       
   208      * The {@code DataSource} provides extra information, such as
       
   209      * the file name, that a CommandMap implementation may use to further
       
   210      * refine the choice of DataContentHandler.  The implementation
       
   211      * in this class simply calls the {@code createDataContentHandler}
       
   212      * method that ignores this argument.
       
   213      *
       
   214      * @param mimeType  the MIME type
       
   215      * @param ds        a DataSource for the data
       
   216      * @return          the DataContentHandler for the MIME type
       
   217      * @since   1.6, JAF 1.1
       
   218      */
       
   219     public DataContentHandler createDataContentHandler(String mimeType,
       
   220                                 DataSource ds) {
       
   221         return createDataContentHandler(mimeType);
       
   222     }
       
   223 
       
   224     /**
       
   225      * Get all the MIME types known to this command map.
       
   226      * If the command map doesn't support this operation,
       
   227      * null is returned.
       
   228      *
       
   229      * @return          array of MIME types as strings, or null if not supported
       
   230      * @since   1.6, JAF 1.1
       
   231      */
       
   232     public String[] getMimeTypes() {
       
   233         return null;
       
   234     }
       
   235 }