1 /*
2 * Copyright 2000-2001 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.nio.channels;
27
28 import java.io.IOException;
29 import java.net.ServerSocket;
30 import java.net.SocketAddress;
31 import java.nio.channels.spi;
32
33
34 /**
35 * A selectable channel for stream-oriented listening sockets.
36 *
37 * <p> Server-socket channels are not a complete abstraction of listening
38 * network sockets. Binding and the manipulation of socket options must be
39 * done through an associated {@link java.net.ServerSocket} object obtained by
40 * invoking the {@link #socket() socket} method. It is not possible to create
41 * a channel for an arbitrary, pre-existing server socket, nor is it possible
42 * to specify the {@link java.net.SocketImpl} object to be used by a server
43 * socket associated with a server-socket channel.
44 *
45 * <p> A server-socket channel is created by invoking the {@link #open() open}
46 * method of this class. A newly-created server-socket channel is open but not
47 * yet bound. An attempt to invoke the {@link #accept() accept} method of an
48 * unbound server-socket channel will cause a {@link NotYetBoundException} to
49 * be thrown. A server-socket channel can be bound by invoking one of the
50 * {@link java.net.ServerSocket#bind(java.net.SocketAddress,int) bind} methods
51 * of an associated server socket.
52 *
53 * <p> Server-socket channels are safe for use by multiple concurrent threads.
54 * </p>
55 *
56 *
57 * @author Mark Reinhold
58 * @author JSR-51 Expert Group
59 * @since 1.4
60 */
61
62 public abstract class ServerSocketChannel
63 extends AbstractSelectableChannel
64 {
65
66 /**
67 * Initializes a new instance of this class.
68 */
69 protected ServerSocketChannel(SelectorProvider provider) {
70 super(provider);
71 }
72
73 /**
74 * Opens a server-socket channel.
75 *
76 * <p> The new channel is created by invoking the {@link
77 * java.nio.channels.spi.SelectorProvider#openServerSocketChannel
78 * openServerSocketChannel} method of the system-wide default {@link
79 * java.nio.channels.spi.SelectorProvider} object.
80 *
81 * <p> The new channel's socket is initially unbound; it must be bound to a
82 * specific address via one of its socket's {@link
83 * java.net.ServerSocket#bind(SocketAddress) bind} methods before
84 * connections can be accepted. </p>
85 *
86 * @return A new socket channel
87 *
88 * @throws IOException
89 * If an I/O error occurs
90 */
91 public static ServerSocketChannel open() throws IOException {
92 return SelectorProvider.provider().openServerSocketChannel();
93 }
94
95 /**
96 * Returns an operation set identifying this channel's supported
97 * operations.
98 *
99 * <p> Server-socket channels only support the accepting of new
100 * connections, so this method returns {@link SelectionKey#OP_ACCEPT}.
101 * </p>
102 *
103 * @return The valid-operation set
104 */
105 public final int validOps() {
106 return SelectionKey.OP_ACCEPT;
107 }
108
109
110 // -- ServerSocket-specific operations --
111
112 /**
113 * Retrieves a server socket associated with this channel.
114 *
115 * <p> The returned object will not declare any public methods that are not
116 * declared in the {@link java.net.ServerSocket} class. </p>
117 *
118 * @return A server socket associated with this channel
119 */
120 public abstract ServerSocket socket();
121
122 /**
123 * Accepts a connection made to this channel's socket.
124 *
125 * <p> If this channel is in non-blocking mode then this method will
126 * immediately return <tt>null</tt> if there are no pending connections.
127 * Otherwise it will block indefinitely until a new connection is available
128 * or an I/O error occurs.
129 *
130 * <p> The socket channel returned by this method, if any, will be in
131 * blocking mode regardless of the blocking mode of this channel.
132 *
133 * <p> This method performs exactly the same security checks as the {@link
134 * java.net.ServerSocket#accept accept} method of the {@link
135 * java.net.ServerSocket} class. That is, if a security manager has been
136 * installed then for each new connection this method verifies that the
137 * address and port number of the connection's remote endpoint are
138 * permitted by the security manager's {@link
139 * java.lang.SecurityManager#checkAccept checkAccept} method. </p>
140 *
141 * @return The socket channel for the new connection,
142 * or <tt>null</tt> if this channel is in non-blocking mode
143 * and no connection is available to be accepted
144 *
145 * @throws ClosedChannelException
146 * If this channel is closed
147 *
148 * @throws AsynchronousCloseException
149 * If another thread closes this channel
150 * while the accept operation is in progress
151 *
152 * @throws ClosedByInterruptException
153 * If another thread interrupts the current thread
154 * while the accept operation is in progress, thereby
155 * closing the channel and setting the current thread's
156 * interrupt status
157 *
158 * @throws NotYetBoundException
159 * If this channel's socket has not yet been bound
160 *
161 * @throws SecurityException
162 * If a security manager has been installed
163 * and it does not permit access to the remote endpoint
164 * of the new connection
165 *
166 * @throws IOException
167 * If some other I/O error occurs
168 */
169 public abstract SocketChannel accept() throws IOException;
170
171 }
Save This Page