com.google.code.yanf4j.core.impl

Class StandardSocketOption

java.lang.Object

com.google.code.yanf4j.core.impl.StandardSocketOption

public class StandardSocketOption
extends Object

Standard socket options

Author:

dennis

Field Summary

Fields

Modifier and Type	Field and Description
static SocketOption<Boolean>	SO_KEEPALIVE Keep connection alive.
static SocketOption<Integer>	SO_LINGER Linger on close if data is present.
static SocketOption<Integer>	SO_RCVBUF The size of the socket receive buffer.
static SocketOption<Boolean>	SO_REUSEADDR Re-use address.
static SocketOption<Integer>	SO_SNDBUF The size of the socket send buffer.
static SocketOption<Boolean>	TCP_NODELAY Disable the Nagle algorithm.

Constructor Summary

Constructors

Constructor and Description
StandardSocketOption()

Method Summary

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SO_KEEPALIVE

public static final SocketOption<Boolean> SO_KEEPALIVE

Keep connection alive.

The value of this socket option is a Boolean that represents whether the option is enabled or disabled. When the SO_KEEPALIVE option is enabled the operating system may use a keep-alive 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.

The initial value of this socket option is FALSE. The socket option may be enabled or disabled at any time.

See Also:

RFC 1122 * Requirements for Internet Hosts -- Communication Layers< /a>, Socket.setKeepAlive(boolean)

SO_SNDBUF

public static final SocketOption<Integer> SO_SNDBUF

The size of the socket send buffer.

The value of this socket option is an 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 hint to the implementation to size the buffer and the actual size may differ. The socket option can be queried to retrieve the actual size.

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.

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.

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 Also:

Socket.setSendBufferSize(int)

SO_RCVBUF

public static final SocketOption<Integer> SO_RCVBUF

The size of the socket receive buffer.

The value of this socket option is an 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 hint to the implementation to size the buffer and the actual size may differ.

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.

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.

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.

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 Also:

RFC 1323: TCP * Extensions for High Performance< /a>, Socket.setReceiveBufferSize(int), ServerSocket.setReceiveBufferSize(int)

SO_REUSEADDR

public static final SocketOption<Boolean> SO_REUSEADDR

Re-use address.

The value of this socket option is a Boolean that represents whether the option is enabled or disabled. The exact semantics of this socket option are socket type and system dependent.

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 TIME_WAIT 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.

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.

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 Also:

RFC 793: * Transmission Control Protocol< /a>, ServerSocket.setReuseAddress(boolean)

SO_LINGER

public static final SocketOption<Integer> SO_LINGER

Linger on close if data is present.

The value of this socket option is an 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 linger interval. The linger interval is the timeout for the 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 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.

This socket option is intended for use with sockets that are configured in blocking mode only. The behavior of the close method when this option is enabled on a non-blocking socket is not defined.

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 Also:

Socket.setSoLinger(boolean, int)

TCP_NODELAY

public static final SocketOption<Boolean> TCP_NODELAY

Disable the Nagle algorithm.

The value of this socket option is a 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 The Nagle Algorithm to coalesce short segments and improve network efficiency.

The default value of this socket option is 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 setOption method to disable the option has no effect.

See Also:

RFC 1122: * Requirements for Internet Hosts -- Communication Layers< /a>, Socket.setTcpNoDelay(boolean)

Constructor Detail

StandardSocketOption

public StandardSocketOption()