--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/nio/channels/spi/SelectorProvider.java Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,286 @@
+/*
+ * Copyright 2000-2006 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.nio.channels.spi;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.nio.channels.*;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.Iterator;
+import java.util.ServiceLoader;
+import java.util.ServiceConfigurationError;
+import sun.security.action.GetPropertyAction;
+
+
+/**
+ * Service-provider class for selectors and selectable channels.
+ *
+ * <p> A selector provider is a concrete subclass of this class that has a
+ * zero-argument constructor and implements the abstract methods specified
+ * below. A given invocation of the Java virtual machine maintains a single
+ * system-wide default provider instance, which is returned by the {@link
+ * #provider() provider} method. The first invocation of that method will locate
+ * the default provider as specified below.
+ *
+ * <p> The system-wide default provider is used by the static <tt>open</tt>
+ * methods of the {@link java.nio.channels.DatagramChannel#open
+ * DatagramChannel}, {@link java.nio.channels.Pipe#open Pipe}, {@link
+ * java.nio.channels.Selector#open Selector}, {@link
+ * java.nio.channels.ServerSocketChannel#open ServerSocketChannel}, and {@link
+ * java.nio.channels.SocketChannel#open SocketChannel} classes. It is also
+ * used by the {@link java.lang.System#inheritedChannel System.inheritedChannel()}
+ * method. A program may make use of a provider other than the default provider
+ * by instantiating that provider and then directly invoking the <tt>open</tt>
+ * methods defined in this class.
+ *
+ * <p> All of the methods in this class are safe for use by multiple concurrent
+ * threads. </p>
+ *
+ *
+ * @author Mark Reinhold
+ * @author JSR-51 Expert Group
+ * @since 1.4
+ */
+
+public abstract class SelectorProvider {
+
+ private static final Object lock = new Object();
+ private static SelectorProvider provider = null;
+
+ /**
+ * Initializes a new instance of this class. </p>
+ *
+ * @throws SecurityException
+ * If a security manager has been installed and it denies
+ * {@link RuntimePermission}<tt>("selectorProvider")</tt>
+ */
+ protected SelectorProvider() {
+ SecurityManager sm = System.getSecurityManager();
+ if (sm != null)
+ sm.checkPermission(new RuntimePermission("selectorProvider"));
+ }
+
+ private static boolean loadProviderFromProperty() {
+ String cn = System.getProperty("java.nio.channels.spi.SelectorProvider");
+ if (cn == null)
+ return false;
+ try {
+ Class c = Class.forName(cn, true,
+ ClassLoader.getSystemClassLoader());
+ provider = (SelectorProvider)c.newInstance();
+ return true;
+ } catch (ClassNotFoundException x) {
+ throw new ServiceConfigurationError(null, x);
+ } catch (IllegalAccessException x) {
+ throw new ServiceConfigurationError(null, x);
+ } catch (InstantiationException x) {
+ throw new ServiceConfigurationError(null, x);
+ } catch (SecurityException x) {
+ throw new ServiceConfigurationError(null, x);
+ }
+ }
+
+ private static boolean loadProviderAsService() {
+
+ ServiceLoader<SelectorProvider> sl =
+ ServiceLoader.load(SelectorProvider.class,
+ ClassLoader.getSystemClassLoader());
+ Iterator<SelectorProvider> i = sl.iterator();
+ for (;;) {
+ try {
+ if (!i.hasNext())
+ return false;
+ provider = i.next();
+ return true;
+ } catch (ServiceConfigurationError sce) {
+ if (sce.getCause() instanceof SecurityException) {
+ // Ignore the security exception, try the next provider
+ continue;
+ }
+ throw sce;
+ }
+ }
+ }
+
+ /**
+ * Returns the system-wide default selector provider for this invocation of
+ * the Java virtual machine.
+ *
+ * <p> The first invocation of this method locates the default provider
+ * object as follows: </p>
+ *
+ * <ol>
+ *
+ * <li><p> If the system property
+ * <tt>java.nio.channels.spi.SelectorProvider</tt> is defined then it is
+ * taken to be the fully-qualified name of a concrete provider class.
+ * The class is loaded and instantiated; if this process fails then an
+ * unspecified error is thrown. </p></li>
+ *
+ * <li><p> If a provider class has been installed in a jar file that is
+ * visible to the system class loader, and that jar file contains a
+ * provider-configuration file named
+ * <tt>java.nio.channels.spi.SelectorProvider</tt> in the resource
+ * directory <tt>META-INF/services</tt>, then the first class name
+ * specified in that file is taken. The class is loaded and
+ * instantiated; if this process fails then an unspecified error is
+ * thrown. </p></li>
+ *
+ * <li><p> Finally, if no provider has been specified by any of the above
+ * means then the system-default provider class is instantiated and the
+ * result is returned. </p></li>
+ *
+ * </ol>
+ *
+ * <p> Subsequent invocations of this method return the provider that was
+ * returned by the first invocation. </p>
+ *
+ * @return The system-wide default selector provider
+ */
+ public static SelectorProvider provider() {
+ synchronized (lock) {
+ if (provider != null)
+ return provider;
+ return (SelectorProvider)AccessController
+ .doPrivileged(new PrivilegedAction() {
+ public Object run() {
+ if (loadProviderFromProperty())
+ return provider;
+ if (loadProviderAsService())
+ return provider;
+ provider = sun.nio.ch.DefaultSelectorProvider.create();
+ return provider;
+ }
+ });
+ }
+ }
+
+ /**
+ * Opens a datagram channel. </p>
+ *
+ * @return The new channel
+ */
+ public abstract DatagramChannel openDatagramChannel()
+ throws IOException;
+
+ /**
+ * Opens a pipe. </p>
+ *
+ * @return The new pipe
+ */
+ public abstract Pipe openPipe()
+ throws IOException;
+
+ /**
+ * Opens a selector. </p>
+ *
+ * @return The new selector
+ */
+ public abstract AbstractSelector openSelector()
+ throws IOException;
+
+ /**
+ * Opens a server-socket channel. </p>
+ *
+ * @return The new channel
+ */
+ public abstract ServerSocketChannel openServerSocketChannel()
+ throws IOException;
+
+ /**
+ * Opens a socket channel. </p>
+ *
+ * @return The new channel
+ */
+ public abstract SocketChannel openSocketChannel()
+ throws IOException;
+
+ /**
+ * Returns the channel inherited from the entity that created this
+ * Java virtual machine.
+ *
+ * <p> On many operating systems a process, such as a Java virtual
+ * machine, can be started in a manner that allows the process to
+ * inherit a channel from the entity that created the process. The
+ * manner in which this is done is system dependent, as are the
+ * possible entities to which the channel may be connected. For example,
+ * on UNIX systems, the Internet services daemon (<i>inetd</i>) is used to
+ * start programs to service requests when a request arrives on an
+ * associated network port. In this example, the process that is started,
+ * inherits a channel representing a network socket.
+ *
+ * <p> In cases where the inherited channel represents a network socket
+ * then the {@link java.nio.channels.Channel Channel} type returned
+ * by this method is determined as follows:
+ *
+ * <ul>
+ *
+ * <li><p> If the inherited channel represents a stream-oriented connected
+ * socket then a {@link java.nio.channels.SocketChannel SocketChannel} is
+ * returned. The socket channel is, at least initially, in blocking
+ * mode, bound to a socket address, and connected to a peer.
+ * </p></li>
+ *
+ * <li><p> If the inherited channel represents a stream-oriented listening
+ * socket then a {@link java.nio.channels.ServerSocketChannel
+ * ServerSocketChannel} is returned. The server-socket channel is, at
+ * least initially, in blocking mode, and bound to a socket address.
+ * </p></li>
+ *
+ * <li><p> If the inherited channel is a datagram-oriented socket
+ * then a {@link java.nio.channels.DatagramChannel DatagramChannel} is
+ * returned. The datagram channel is, at least initially, in blocking
+ * mode, and bound to a socket address.
+ * </p></li>
+ *
+ * </ul>
+ *
+ * <p> In addition to the network-oriented channels described, this method
+ * may return other kinds of channels in the future.
+ *
+ * <p> The first invocation of this method creates the channel that is
+ * returned. Subsequent invocations of this method return the same
+ * channel. </p>
+ *
+ * @return The inherited channel, if any, otherwise <tt>null</tt>.
+ *
+ * @throws IOException
+ * If an I/O error occurs
+ *
+ * @throws SecurityException
+ * If a security manager has been installed and it denies
+ * {@link RuntimePermission}<tt>("inheritedChannel")</tt>
+ *
+ * @since 1.5
+ */
+ public Channel inheritedChannel() throws IOException {
+ return null;
+ }
+
+}