/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package java.net; /** * Defines an interface for socket implementations to get and set socket * options. It is implemented by the classes {@code SocketImpl} and {@code * DatagramSocketImpl}. * * @see SocketImpl * @see DatagramSocketImpl */ public interface SocketOptions { /** * Number of seconds to wait when closing a socket if there is still some buffered data to be * sent. * *

The option can be set to disabled using {@link #setOption(int, Object)} with a value of * {@code Boolean.FALSE}. * *

If this option is set to 0, the TCP socket is closed forcefully and the call to * {@code close} returns immediately. * * If this option is disabled, closing a socket will return immediately and the close will be * handled in the background. * *

If this option is set to a value greater than 0, the value is interpreted as the number of * seconds to wait. If all data could be sent during this time, the socket is closed normally. * Otherwise the connection will be closed forcefully. * *

Valid numeric values for this option are in the range 0 to 65535 inclusive. (Larger * timeouts will be treated as 65535s timeouts; roughly 18 hours.) * *

This option is intended for use with sockets in blocking mode. The behavior of this option * for non-blocking sockets is undefined. */ public static final int SO_LINGER = 128; /** * Integer timeout in milliseconds for blocking accept or read/receive operations (but not * write/send operations). A timeout of 0 means no timeout. Negative * timeouts are not allowed. * *

An {@code InterruptedIOException} is thrown if this timeout expires. */ public static final int SO_TIMEOUT = 4102; /** * This boolean option specifies whether data is sent immediately on this socket or buffered. *

* If set to {@code Boolean.TRUE} the Nagle algorithm is disabled and there is no buffering. * This could lead to low packet efficiency. When set to {@code Boolean.FALSE} the the socket * implementation uses buffering to try to reach a higher packet efficiency. * *

See RFC 1122: Requirements for Internet * Hosts -- Communication Layers for more information about buffering and the Nagle * algorithm. */ public static final int TCP_NODELAY = 1; /** * This is an IPv4-only socket option whose functionality is subsumed by * {@link #IP_MULTICAST_IF2} and not implemented on Android. */ public static final int IP_MULTICAST_IF = 16; /** * This option does not correspond to any Unix socket option and is not implemented on Android. */ public static final int SO_BINDADDR = 15; /** * This boolean option specifies whether a reuse of a local address is allowed when another * socket has not yet been removed by the operating system. * *

For connection-oriented sockets, if this option is disabled and if there is another socket * in state TIME_WAIT on a given address then another socket binding to that address would fail. * Setting this value after a socket is bound has no effect. * *

For datagram sockets this option determines whether several sockets can listen on the * same address; when enabled each socket will receive a copy of the datagram. * *

See RFC 793: Transmission Control Protocol * for more information about socket re-use. */ public static final int SO_REUSEADDR = 4; /** * The size in bytes of a socket's send buffer. This must be an integer greater than 0. * This is a hint to the kernel; the kernel may use a larger buffer. * *

For datagram sockets, it is implementation-defined whether packets larger than * this size can be sent. */ public static final int SO_SNDBUF = 4097; /** * The size in bytes of a socket's receive buffer. This must be an integer greater than 0. * This is a hint to the kernel; the kernel may use a larger buffer. * *

For datagram sockets, packets larger than this value will be discarded. * *

See RFC1323: TCP Extensions for High * Performance for more information about TCP/IP buffering. */ public static final int SO_RCVBUF = 4098; /** * This boolean option specifies whether the kernel sends keepalive messages on * connection-oriented sockets. * *

See RFC 1122: Requirements for Internet * Hosts -- Communication Layers for more information on keep-alive. */ public static final int SO_KEEPALIVE = 8; /** * This integer option specifies the value for the type-of-service field of the IPv4 header, * or the traffic class field of the IPv6 header. These correspond to the IP_TOS and IPV6_TCLASS * socket options. These may be ignored by the underlying OS. Values must be between 0 and 255 * inclusive. * *

See RFC 1349 for more about IPv4 * and RFC 2460 for more about IPv6. */ public static final int IP_TOS = 3; /** * This boolean option specifies whether the local loopback of multicast packets is * enabled or disabled. This loopback is enabled by default on multicast sockets. * *

See RFC 1112: Host Extensions for IP * Multicasting for more information about IP multicast. * *

See {@link MulticastSocket#setLoopbackMode}. */ public static final int IP_MULTICAST_LOOP = 18; /** * This boolean option can be used to enable or disable broadcasting on datagram sockets. This * option must be enabled to send broadcast messages. The default value is false. */ public static final int SO_BROADCAST = 32; /** * This boolean option specifies whether sending TCP urgent data is supported on * this socket or not. */ public static final int SO_OOBINLINE = 4099; /** * This integer option sets the outgoing interface for multicast packets * using an interface index. * *

See RFC 1112: Host Extensions for IP * Multicasting for more information about IP multicast. */ public static final int IP_MULTICAST_IF2 = 31; /** * Gets the value for the specified socket option. * * @return the option value. * @param optID * the option identifier. * @throws SocketException * if an error occurs reading the option value. */ public Object getOption(int optID) throws SocketException; /** * Sets the value of the specified socket option. * * @param optID * the option identifier. * @param val * the value to be set for the option. * @throws SocketException * if an error occurs setting the option value. */ public void setOption(int optID, Object val) throws SocketException; }