jdk/src/share/classes/java/net/StandardSocketOptions.java
changeset 9679 d98ae8bc45fc
parent 5506 202f599c92aa
child 14342 8435a30053c1
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/net/StandardSocketOptions.java	Mon May 09 18:45:33 2011 +0100
@@ -0,0 +1,367 @@
+/*
+ * Copyright (c) 2007, 2009, Oracle and/or its affiliates. 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.net;
+
+/**
+ * Defines the <em>standard</em> socket options.
+ *
+ * <p> The {@link SocketOption#name name} of each socket option defined by this
+ * class is its field name.
+ *
+ * <p> In this release, the socket options defined here are used by {@link
+ * java.nio.channels.NetworkChannel network} channels in the {@link
+ * java.nio.channels channels} package.
+ *
+ * @since 1.7
+ */
+
+public final class StandardSocketOptions {
+    private StandardSocketOptions() { }
+
+    // -- SOL_SOCKET --
+
+    /**
+     * Allow transmission of broadcast datagrams.
+     *
+     * <p> The value of this socket option is a {@code Boolean} that represents
+     * whether the option is enabled or disabled. The option is specific to
+     * datagram-oriented sockets sending to {@link java.net.Inet4Address IPv4}
+     * broadcast addresses. When the socket option is enabled then the socket
+     * can be used to send <em>broadcast datagrams</em>.
+     *
+     * <p> The initial value of this socket option is {@code FALSE}. The socket
+     * option may be enabled or disabled at any time. Some operating systems may
+     * require that the Java virtual machine be started with implementation
+     * specific privileges to enable this option or send broadcast datagrams.
+     *
+     * @see <a href="http://www.ietf.org/rfc/rfc919.txt">RFC&nbsp;929:
+     * Broadcasting Internet Datagrams</a>
+     * @see DatagramSocket#setBroadcast
+     */
+    public static final SocketOption<Boolean> SO_BROADCAST =
+        new StdSocketOption<Boolean>("SO_BROADCAST", Boolean.class);
+
+    /**
+     * Keep connection alive.
+     *
+     * <p> The value of this socket option is a {@code Boolean} that represents
+     * whether the option is enabled or disabled. When the {@code SO_KEEPALIVE}
+     * option is enabled the operating system may use a <em>keep-alive</em>
+     * mechanism to periodically probe the other end of a connection when the
+     * connection is otherwise idle. The exact semantics of the keep alive
+     * mechanism is system dependent and therefore unspecified.
+     *
+     * <p> The initial value of this socket option is {@code FALSE}. The socket
+     * option may be enabled or disabled at any time.
+     *
+     * @see <a href="http://www.ietf.org/rfc/rfc1122.txt">RFC&nbsp;1122
+     * Requirements for Internet Hosts -- Communication Layers</a>
+     * @see Socket#setKeepAlive
+     */
+    public static final SocketOption<Boolean> SO_KEEPALIVE =
+        new StdSocketOption<Boolean>("SO_KEEPALIVE", Boolean.class);
+
+    /**
+     * The size of the socket send buffer.
+     *
+     * <p> The value of this socket option is an {@code Integer} that is the
+     * size of the socket send buffer in bytes. The socket send buffer is an
+     * output buffer used by the networking implementation. It may need to be
+     * increased for high-volume connections. The value of the socket option is
+     * a <em>hint</em> to the implementation to size the buffer and the actual
+     * size may differ. The socket option can be queried to retrieve the actual
+     * size.
+     *
+     * <p> For datagram-oriented sockets, the size of the send buffer may limit
+     * the size of the datagrams that may be sent by the socket. Whether
+     * datagrams larger than the buffer size are sent or discarded is system
+     * dependent.
+     *
+     * <p> The initial/default size of the socket send buffer and the range of
+     * allowable values is system dependent although a negative size is not
+     * allowed. An attempt to set the socket send buffer to larger than its
+     * maximum size causes it to be set to its maximum size.
+     *
+     * <p> An implementation allows this socket option to be set before the
+     * socket is bound or connected. Whether an implementation allows the
+     * socket send buffer to be changed after the socket is bound is system
+     * dependent.
+     *
+     * @see Socket#setSendBufferSize
+     */
+    public static final SocketOption<Integer> SO_SNDBUF =
+        new StdSocketOption<Integer>("SO_SNDBUF", Integer.class);
+
+
+    /**
+     * The size of the socket receive buffer.
+     *
+     * <p> The value of this socket option is an {@code Integer} that is the
+     * size of the socket receive buffer in bytes. The socket receive buffer is
+     * an input buffer used by the networking implementation. It may need to be
+     * increased for high-volume connections or decreased to limit the possible
+     * backlog of incoming data. The value of the socket option is a
+     * <em>hint</em> to the implementation to size the buffer and the actual
+     * size may differ.
+     *
+     * <p> For datagram-oriented sockets, the size of the receive buffer may
+     * limit the size of the datagrams that can be received. Whether datagrams
+     * larger than the buffer size can be received is system dependent.
+     * Increasing the socket receive buffer may be important for cases where
+     * datagrams arrive in bursts faster than they can be processed.
+     *
+     * <p> In the case of stream-oriented sockets and the TCP/IP protocol, the
+     * size of the socket receive buffer may be used when advertising the size
+     * of the TCP receive window to the remote peer.
+     *
+     * <p> The initial/default size of the socket receive buffer and the range
+     * of allowable values is system dependent although a negative size is not
+     * allowed. An attempt to set the socket receive buffer to larger than its
+     * maximum size causes it to be set to its maximum size.
+     *
+     * <p> An implementation allows this socket option to be set before the
+     * socket is bound or connected. Whether an implementation allows the
+     * socket receive buffer to be changed after the socket is bound is system
+     * dependent.
+     *
+     * @see <a href="http://www.ietf.org/rfc/rfc1323.txt">RFC&nbsp;1323: TCP
+     * Extensions for High Performance</a>
+     * @see Socket#setReceiveBufferSize
+     * @see ServerSocket#setReceiveBufferSize
+     */
+    public static final SocketOption<Integer> SO_RCVBUF =
+        new StdSocketOption<Integer>("SO_RCVBUF", Integer.class);
+
+    /**
+     * Re-use address.
+     *
+     * <p> The value of this socket option is a {@code Boolean} that represents
+     * whether the option is enabled or disabled. The exact semantics of this
+     * socket option are socket type and system dependent.
+     *
+     * <p> In the case of stream-oriented sockets, this socket option will
+     * usually determine whether the socket can be bound to a socket address
+     * when a previous connection involving that socket address is in the
+     * <em>TIME_WAIT</em> state. On implementations where the semantics differ,
+     * and the socket option is not required to be enabled in order to bind the
+     * socket when a previous connection is in this state, then the
+     * implementation may choose to ignore this option.
+     *
+     * <p> For datagram-oriented sockets the socket option is used to allow
+     * multiple programs bind to the same address. This option should be enabled
+     * when the socket is to be used for Internet Protocol (IP) multicasting.
+     *
+     * <p> An implementation allows this socket option to be set before the
+     * socket is bound or connected. Changing the value of this socket option
+     * after the socket is bound has no effect. The default value of this
+     * socket option is system dependent.
+     *
+     * @see <a href="http://www.ietf.org/rfc/rfc793.txt">RFC&nbsp;793: Transmission
+     * Control Protocol</a>
+     * @see ServerSocket#setReuseAddress
+     */
+    public static final SocketOption<Boolean> SO_REUSEADDR =
+        new StdSocketOption<Boolean>("SO_REUSEADDR", Boolean.class);
+
+    /**
+     * Linger on close if data is present.
+     *
+     * <p> The value of this socket option is an {@code Integer} that controls
+     * the action taken when unsent data is queued on the socket and a method
+     * to close the socket is invoked. If the value of the socket option is zero
+     * or greater, then it represents a timeout value, in seconds, known as the
+     * <em>linger interval</em>. The linger interval is the timeout for the
+     * {@code close} method to block while the operating system attempts to
+     * transmit the unsent data or it decides that it is unable to transmit the
+     * data. If the value of the socket option is less than zero then the option
+     * is disabled. In that case the {@code close} method does not wait until
+     * unsent data is transmitted; if possible the operating system will transmit
+     * any unsent data before the connection is closed.
+     *
+     * <p> This socket option is intended for use with sockets that are configured
+     * in {@link java.nio.channels.SelectableChannel#isBlocking() blocking} mode
+     * only. The behavior of the {@code close} method when this option is
+     * enabled on a non-blocking socket is not defined.
+     *
+     * <p> The initial value of this socket option is a negative value, meaning
+     * that the option is disabled. The option may be enabled, or the linger
+     * interval changed, at any time. The maximum value of the linger interval
+     * is system dependent. Setting the linger interval to a value that is
+     * greater than its maximum value causes the linger interval to be set to
+     * its maximum value.
+     *
+     * @see Socket#setSoLinger
+     */
+    public static final SocketOption<Integer> SO_LINGER =
+        new StdSocketOption<Integer>("SO_LINGER", Integer.class);
+
+
+    // -- IPPROTO_IP --
+
+    /**
+     * The Type of Service (ToS) octet in the Internet Protocol (IP) header.
+     *
+     * <p> The value of this socket option is an {@code Integer} representing
+     * the value of the ToS octet in IP packets sent by sockets to an {@link
+     * StandardProtocolFamily#INET IPv4} socket. The interpretation of the ToS
+     * octet is network specific and is not defined by this class. Further
+     * information on the ToS octet can be found in <a
+     * href="http://www.ietf.org/rfc/rfc1349.txt">RFC&nbsp;1349</a> and <a
+     * href="http://www.ietf.org/rfc/rfc2474.txt">RFC&nbsp;2474</a>. The value
+     * of the socket option is a <em>hint</em>. An implementation may ignore the
+     * value, or ignore specific values.
+     *
+     * <p> The initial/default value of the TOS field in the ToS octet is
+     * implementation specific but will typically be {@code 0}. For
+     * datagram-oriented sockets the option may be configured at any time after
+     * the socket has been bound. The new value of the octet is used when sending
+     * subsequent datagrams. It is system dependent whether this option can be
+     * queried or changed prior to binding the socket.
+     *
+     * <p> The behavior of this socket option on a stream-oriented socket, or an
+     * {@link StandardProtocolFamily#INET6 IPv6} socket, is not defined in this
+     * release.
+     *
+     * @see DatagramSocket#setTrafficClass
+     */
+    public static final SocketOption<Integer> IP_TOS =
+        new StdSocketOption<Integer>("IP_TOS", Integer.class);
+
+    /**
+     * The network interface for Internet Protocol (IP) multicast datagrams.
+     *
+     * <p> The value of this socket option is a {@link NetworkInterface} that
+     * represents the outgoing interface for multicast datagrams sent by the
+     * datagram-oriented socket. For {@link StandardProtocolFamily#INET6 IPv6}
+     * sockets then it is system dependent whether setting this option also
+     * sets the outgoing interface for multlicast datagrams sent to IPv4
+     * addresses.
+     *
+     * <p> The initial/default value of this socket option may be {@code null}
+     * to indicate that outgoing interface will be selected by the operating
+     * system, typically based on the network routing tables. An implementation
+     * allows this socket option to be set after the socket is bound. Whether
+     * the socket option can be queried or changed prior to binding the socket
+     * is system dependent.
+     *
+     * @see java.nio.channels.MulticastChannel
+     * @see MulticastSocket#setInterface
+     */
+    public static final SocketOption<NetworkInterface> IP_MULTICAST_IF =
+        new StdSocketOption<NetworkInterface>("IP_MULTICAST_IF", NetworkInterface.class);
+
+    /**
+     * The <em>time-to-live</em> for Internet Protocol (IP) multicast datagrams.
+     *
+     * <p> The value of this socket option is an {@code Integer} in the range
+     * <tt>0&nbsp;<=&nbsp;value&nbsp;<=&nbsp;255</tt>. It is used to control
+     * the scope of multicast datagrams sent by the datagram-oriented socket.
+     * In the case of an {@link StandardProtocolFamily#INET IPv4} socket
+     * the option is the time-to-live (TTL) on multicast datagrams sent by the
+     * socket. Datagrams with a TTL of zero are not transmitted on the network
+     * but may be delivered locally. In the case of an {@link
+     * StandardProtocolFamily#INET6 IPv6} socket the option is the
+     * <em>hop limit</em> which is number of <em>hops</em> that the datagram can
+     * pass through before expiring on the network. For IPv6 sockets it is
+     * system dependent whether the option also sets the <em>time-to-live</em>
+     * on multicast datagrams sent to IPv4 addresses.
+     *
+     * <p> The initial/default value of the time-to-live setting is typically
+     * {@code 1}. An implementation allows this socket option to be set after
+     * the socket is bound. Whether the socket option can be queried or changed
+     * prior to binding the socket is system dependent.
+     *
+     * @see java.nio.channels.MulticastChannel
+     * @see MulticastSocket#setTimeToLive
+     */
+    public static final SocketOption<Integer> IP_MULTICAST_TTL =
+        new StdSocketOption<Integer>("IP_MULTICAST_TTL", Integer.class);
+
+    /**
+     * Loopback for Internet Protocol (IP) multicast datagrams.
+     *
+     * <p> The value of this socket option is a {@code Boolean} that controls
+     * the <em>loopback</em> of multicast datagrams. The value of the socket
+     * option represents if the option is enabled or disabled.
+     *
+     * <p> The exact semantics of this socket options are system dependent.
+     * In particular, it is system dependent whether the loopback applies to
+     * multicast datagrams sent from the socket or received by the socket.
+     * For {@link StandardProtocolFamily#INET6 IPv6} sockets then it is
+     * system dependent whether the option also applies to multicast datagrams
+     * sent to IPv4 addresses.
+     *
+     * <p> The initial/default value of this socket option is {@code TRUE}. An
+     * implementation allows this socket option to be set after the socket is
+     * bound. Whether the socket option can be queried or changed prior to
+     * binding the socket is system dependent.
+     *
+     * @see java.nio.channels.MulticastChannel
+     *  @see MulticastSocket#setLoopbackMode
+     */
+    public static final SocketOption<Boolean> IP_MULTICAST_LOOP =
+        new StdSocketOption<Boolean>("IP_MULTICAST_LOOP", Boolean.class);
+
+
+    // -- IPPROTO_TCP --
+
+    /**
+     * Disable the Nagle algorithm.
+     *
+     * <p> The value of this socket option is a {@code Boolean} that represents
+     * whether the option is enabled or disabled. The socket option is specific to
+     * stream-oriented sockets using the TCP/IP protocol. TCP/IP uses an algorithm
+     * known as <em>The Nagle Algorithm</em> to coalesce short segments and
+     * improve network efficiency.
+     *
+     * <p> The default value of this socket option is {@code FALSE}. The
+     * socket option should only be enabled in cases where it is known that the
+     * coalescing impacts performance. The socket option may be enabled at any
+     * time. In other words, the Nagle Algorithm can be disabled. Once the option
+     * is enabled, it is system dependent whether it can be subsequently
+     * disabled. If it cannot, then invoking the {@code setOption} method to
+     * disable the option has no effect.
+     *
+     * @see <a href="http://www.ietf.org/rfc/rfc1122.txt">RFC&nbsp;1122:
+     * Requirements for Internet Hosts -- Communication Layers</a>
+     * @see Socket#setTcpNoDelay
+     */
+    public static final SocketOption<Boolean> TCP_NODELAY =
+        new StdSocketOption<Boolean>("TCP_NODELAY", Boolean.class);
+
+
+    private static class StdSocketOption<T> implements SocketOption<T> {
+        private final String name;
+        private final Class<T> type;
+        StdSocketOption(String name, Class<T> type) {
+            this.name = name;
+            this.type = type;
+        }
+        @Override public String name() { return name; }
+        @Override public Class<T> type() { return type; }
+        @Override public String toString() { return name; }
+    }
+}