Binds the socket to a local address.

  Binds the socket to a local address.

If the address is null, then the system will pick up an ephemeral port and a valid local address to bind the socket.
Parameters:
- bindpoint - the SocketAddress to bind to
Throws:
- IOException - if the bind operation fails, or if the socket is already bound.
- IllegalArgumentException - if bindpoint is a SocketAddress subclass not supported by this socket
Since: 1.4
See Also: Socket.isBound(),

  Closes this socket.

  Closes this socket.

Any thread currently blocked in an I/O operation upon this socket will throw a SocketException.

Once a socket has been closed, it is not available for further networking use (i.e. can't be reconnected or rebound). A new socket needs to be created.

Closing this socket will also close the socket's InputStream and OutputStream.

If this socket has an associated channel then the channel is closed as well.
Throws:
- IOException - if an I/O error occurs when closing this socket.
See Also: Socket.isClosed(),

  Connects this socket to the server.

  Connects this socket to the server.
Parameters:
- endpoint - the SocketAddress
Throws:
- IOException - if an error occurs during the connection
- java.nio.channels.IllegalBlockingModeException - if this socket has an associated channel, and the channel is in non-blocking mode
- IllegalArgumentException - if endpoint is null or is a SocketAddress subclass not supported by this socket
Since: 1.4

  Connects this socket to the server with a specified timeout value.

  Connects this socket to the server with a specified timeout value.
A timeout of zero is interpreted as an infinite timeout. The connection
will then block until established or an error occurs.
Parameters:
- endpoint - the SocketAddress
- timeout - the timeout value to be used in milliseconds.
Throws:
- IOException - if an error occurs during the connection
- SocketTimeoutException - if timeout expires before connecting
- java.nio.channels.IllegalBlockingModeException - if this socket has an associated channel, and the channel is in non-blocking mode
- IllegalArgumentException - if endpoint is null or is a SocketAddress subclass not supported by this socket
Since: 1.4

  Creates the socket implementation.

  Creates the socket implementation.
Parameters:
- stream - a boolean value : true for a TCP socket, false for UDP.
Throws:
- IOException - if creation fails
Since: 1.4

  Returns the unique SocketChannel object associated with this socket, if any.

  Returns the unique SocketChannel object associated with this socket, if any.

A socket will have a channel if, and only if, the channel itself was created via the SocketChannel.open or ServerSocketChannel.accept methods.
Returns: the socket channel associated with this socket, or null if this socket was not created for a channel
Since: 1.4

  Get the SocketImpl attached to this socket, creating it if necessary.

  Get the SocketImpl attached to this socket, creating
it if necessary.
Returns: the SocketImpl attached to that ServerSocket.
Throws:
- SocketException - if creation fails
Since: 1.4

  Returns the address to which the socket is connected.

  Returns the address to which the socket is connected.
Returns: the remote IP address to which this socket is connected, or null if the socket is not connected.

  Returns an input stream for this socket.

  Returns an input stream for this socket.

If this socket has an associated channel then the resulting input stream delegates all of its operations to the channel. If the channel is in non-blocking mode then the input stream's read operations will throw an IllegalBlockingModeException.

Under abnormal conditions the underlying connection may be broken by the remote host or the network software (for example a connection reset in the case of TCP connections). When a broken connection is detected by the network software the following applies to the returned input stream :-

• The network software may discard bytes that are buffered by the socket. Bytes that aren't discarded by the network software can be read using read.

• If there are no bytes buffered on the socket, or all buffered bytes have been consumed by read, then all subsequent calls to read will throw an IOException.

• If there are no bytes buffered on the socket, and the socket has not been closed using close, then available will return 0.

Closing the returned InputStream will close the associated socket.
Returns: an input stream for reading bytes from this socket.
Throws:
- IOException - if an I/O error occurs when creating the input stream, the socket is closed, the socket is not connected, or the socket input has been shutdown using {@link #shutdownInput()}

  Tests if SO_KEEPALIVE is enabled.

  Tests if SO_KEEPALIVE is enabled.
Returns: a boolean indicating whether or not SO_KEEPALIVE is enabled.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: 1.3
See Also: Socket.setKeepAlive(boolean),

  Gets the local address to which the socket is bound.

  Gets the local address to which the socket is bound.
Returns: the local address to which the socket is bound or InetAddress.anyLocalAddress() if the socket is not bound yet.
Since: JDK1.1

  Returns the local port to which this socket is bound.

  Returns the local port to which this socket is bound.
Returns: the local port number to which this socket is bound or -1 if the socket is not bound yet.

  Returns the address of the endpoint this socket is bound to, or null if it is not bound yet.

  Returns the address of the endpoint this socket is bound to, or
null if it is not bound yet.
Returns: a SocketAddress representing the local endpoint of this socket, or null if it is not bound yet.
Since: 1.4
See Also: Socket.getLocalAddress(), Socket.getLocalPort(), Socket.bind(SocketAddress),

  Tests if OOBINLINE is enabled.

  Tests if OOBINLINE is enabled.
Returns: a boolean indicating whether or not OOBINLINE is enabled.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: 1.4
See Also: Socket.setOOBInline(boolean),

  Returns an output stream for this socket.

  Returns an output stream for this socket.

If this socket has an associated channel then the resulting output stream delegates all of its operations to the channel. If the channel is in non-blocking mode then the output stream's write operations will throw an IllegalBlockingModeException.

Closing the returned OutputStream will close the associated socket.
Returns: an output stream for writing bytes to this socket.
Throws:
- IOException - if an I/O error occurs when creating the output stream or if the socket is not connected.

  Returns the remote port to which this socket is connected.

  Returns the remote port to which this socket is connected.
Returns: the remote port number to which this socket is connected, or 0 if the socket is not connected yet.

  Gets the value of the SO_RCVBUF option for this Socket, that is the buffer size used by the platform for input on this Socket.

  Gets the value of the SO_RCVBUF option for this Socket,
that is the buffer size used by the platform for
input on this Socket.
Returns: the value of the SO_RCVBUF option for this Socket.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: 1.2
See Also: Socket.setReceiveBufferSize(int),

  Returns the address of the endpoint this socket is connected to, or null if it is unconnected.

  Returns the address of the endpoint this socket is connected to, or
null if it is unconnected.
Returns: a SocketAddress reprensenting the remote endpoint of this socket, or null if it is not connected yet.
Since: 1.4
See Also: Socket.getInetAddress(), Socket.getPort(), Socket.connect(SocketAddress, int), Socket.connect(SocketAddress),

  Tests if SO_REUSEADDR is enabled.

  Tests if SO_REUSEADDR is enabled.
Returns: a boolean indicating whether or not SO_REUSEADDR is enabled.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: 1.4
See Also: Socket.setReuseAddress(boolean),

  Get value of the SO_SNDBUF option for this Socket, that is the buffer size used by the platform for output on this Socket.

  Get value of the SO_SNDBUF option for this Socket,
that is the buffer size used by the platform
for output on this Socket.
Returns: the value of the SO_SNDBUF option for this Socket.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: 1.2
See Also: Socket.setSendBufferSize(int),

  Returns setting for SO_LINGER.

  Returns setting for SO_LINGER. -1 returns implies that the
option is disabled.

The setting only affects socket close.
Returns: the setting for SO_LINGER.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: JDK1.1
See Also: Socket.setSoLinger(boolean, int),

  Returns setting for SO_TIMEOUT.

  Returns setting for SO_TIMEOUT. 0 returns implies that the
option is disabled (i.e., timeout of infinity).
Returns: the setting for SO_TIMEOUT
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: JDK1.1
See Also: Socket.setSoTimeout(int),

  Tests if TCP_NODELAY is enabled.

  Tests if TCP_NODELAY is enabled.
Returns: a boolean indicating whether or not TCP_NODELAY is enabled.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: JDK1.1
See Also: Socket.setTcpNoDelay(boolean),

  Gets traffic class or type-of-service in the IP header for packets sent from this Socket

  Gets traffic class or type-of-service in the IP header for packets sent from this Socket

As the underlying network implementation may ignore the traffic class or type-of-service set using Socket.setTrafficClass(int) this method may return a different value than was previously set using the Socket.setTrafficClass(int) method on this Socket.
Returns: the traffic class or type-of-service already set
Throws:
- SocketException - if there is an error obtaining the traffic class or type-of-service value.
Since: 1.4
See Also: Socket.setTrafficClass(int),

  Returns the binding state of the socket.

  Returns the binding state of the socket.
Returns: true if the socket successfuly bound to an address
Since: 1.4
See Also: Socket.bind(java.net.SocketAddress),

  Returns the closed state of the socket.

  Returns the closed state of the socket.
Returns: true if the socket has been closed
Since: 1.4
See Also: Socket.close(),

  Returns the connection state of the socket.

  Returns the connection state of the socket.
Returns: true if the socket successfuly connected to a server
Since: 1.4

  Returns whether the read-half of the socket connection is closed.

  Returns whether the read-half of the socket connection is closed.
Returns: true if the input of the socket has been shutdown
Since: 1.4
See Also: Socket.shutdownInput(),

  Returns whether the write-half of the socket connection is closed.

  Returns whether the write-half of the socket connection is closed.
Returns: true if the output of the socket has been shutdown
Since: 1.4
See Also: Socket.shutdownOutput(),

set the flags after an accept() call.

  Send one byte of urgent data on the socket.

  Send one byte of urgent data on the socket. The byte to be sent is the lowest eight
bits of the data parameter. The urgent byte is
sent after any preceding writes to the socket OutputStream
and before any future writes to the OutputStream.
Parameters:
- data - The byte of data to send
Throws:
- IOException - if there is an error sending the data.
Since: 1.4

  Sets impl to the system-default type of SocketImpl.

  Sets impl to the system-default type of SocketImpl.
Since: 1.4

  Enable/disable SO_KEEPALIVE.

  Enable/disable SO_KEEPALIVE.
Parameters:
- on - whether or not to have socket keep alive turned on.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: 1.3
See Also: Socket.getKeepAlive(),

  Enable/disable OOBINLINE (receipt of TCP urgent data) By default, this option is disabled and TCP urgent data received on a socket is silently discarded.

  Enable/disable OOBINLINE (receipt of TCP urgent data) By default, this option is disabled and TCP urgent data received on a socket is silently discarded. If the user wishes to receive urgent data, then this option must be enabled. When enabled, urgent data is received inline with normal data.

Note, only limited support is provided for handling incoming urgent data. In particular, no notification of incoming urgent data is provided and there is no capability to distinguish between normal data and urgent data unless provided by a higher level protocol.
Parameters:
- on - true to enable OOBINLINE, false to disable.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: 1.4
See Also: Socket.getOOBInline(),

  Sets performance preferences for this socket.

  Sets performance preferences for this socket.

Sockets use the TCP/IP protocol by default. Some implementations may offer alternative protocols which have different performance characteristics than TCP/IP. This method allows the application to express its own preferences as to how these tradeoffs should be made when the implementation chooses from the available protocols.

Performance preferences are described by three integers whose values indicate the relative importance of short connection time, low latency, and high bandwidth. The absolute values of the integers are irrelevant; in order to choose a protocol the values are simply compared, with larger values indicating stronger preferences. Negative values represent a lower priority than positive values. If the application prefers short connection time over both low latency and high bandwidth, for example, then it could invoke this method with the values (1, 0, 0). If the application prefers high bandwidth above low latency, and low latency above short connection time, then it could invoke this method with the values (0, 1, 2).

Invoking this method after this socket has been connected will have no effect.
Parameters:
- connectionTime - An int expressing the relative importance of a short connection time
- latency - An int expressing the relative importance of low latency
- bandwidth - An int expressing the relative importance of high bandwidth
Since: 1.5

  Sets the SO_RCVBUF option to the specified value for this Socket.

  Sets the SO_RCVBUF option to the specified value for this Socket. The SO_RCVBUF option is used by the platform's networking code as a hint for the size to set the underlying network I/O buffers.

Increasing the receive buffer size can increase the performance of network I/O for high-volume connection, while decreasing it can help reduce the backlog of incoming data.

Because SO_RCVBUF is a hint, applications that want to verify what size the buffers were set to should call Socket.getReceiveBufferSize().

The value of SO_RCVBUF is also used to set the TCP receive window that is advertized to the remote peer. Generally, the window size can be modified at any time when a socket is connected. However, if a receive window larger than 64K is required then this must be requested before the socket is connected to the remote peer. There are two cases to be aware of:

1. For sockets accepted from a ServerSocket, this must be done by calling ServerSocket.setReceiveBufferSize(int) before the ServerSocket is bound to a local address.

2. For client sockets, setReceiveBufferSize() must be called before connecting the socket to its remote peer.

Parameters:
- size - the size to which to set the receive buffer size. This value must be greater than 0.
Throws:
- IllegalArgumentException - if the value is 0 or is negative.
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: 1.2
See Also: Socket.getReceiveBufferSize(), ServerSocket.setReceiveBufferSize(int),

  Enable/disable the SO_REUSEADDR socket option.

  Enable/disable the SO_REUSEADDR socket option.

When a TCP connection is closed the connection may remain in a timeout state for a period of time after the connection is closed (typically known as the TIME_WAIT state or 2MSL wait state). For applications using a well known socket address or port it may not be possible to bind a socket to the required SocketAddress if there is a connection in the timeout state involving the socket address or port.

Enabling SO_REUSEADDR prior to binding the socket using Socket.bind(SocketAddress) allows the socket to be bound even though a previous connection is in a timeout state.

When a Socket is created the initial setting of SO_REUSEADDR is disabled.

The behaviour when SO_REUSEADDR is enabled or disabled after a socket is bound (See Socket.isBound()) is not defined.
Parameters:
- on - whether to enable or disable the socket option
Throws:
- SocketException - if an error occurs enabling or disabling the SO_RESUEADDR socket option, or the socket is closed.
Since: 1.4
See Also: Socket.getReuseAddress(), Socket.bind(SocketAddress), Socket.isClosed(), Socket.isBound(),

  Sets the SO_SNDBUF option to the specified value for this Socket.

  Sets the SO_SNDBUF option to the specified value for this Socket. The SO_SNDBUF option is used by the platform's networking code as a hint for the size to set the underlying network I/O buffers.

Because SO_SNDBUF is a hint, applications that want to verify what size the buffers were set to should call Socket.getSendBufferSize().
Parameters:
- size - the size to which to set the send buffer size. This value must be greater than 0.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
- IllegalArgumentException - if the value is 0 or is negative.
Since: 1.2
See Also: Socket.getSendBufferSize(),

  Sets the client socket implementation factory for the application.

  Sets the client socket implementation factory for the application. The factory can be specified only once.

When an application creates a new client socket, the socket implementation factory's createSocketImpl method is called to create the actual socket implementation.

Passing null to the method is a no-op unless the factory was already set.

If there is a security manager, this method first calls the security manager's checkSetFactory method to ensure the operation is allowed. This could result in a SecurityException.
Parameters:
- fac - the desired factory.
Throws:
- IOException - if an I/O error occurs when setting the socket factory.
- SocketException - if the factory is already defined.
- SecurityException - if a security manager exists and its checkSetFactory method doesn't allow the operation.
See Also: SocketImplFactory.createSocketImpl(), SecurityManager.checkSetFactory(),

  Enable/disable SO_LINGER with the specified linger time in seconds.

  Enable/disable SO_LINGER with the specified linger time in seconds.
The maximum timeout value is platform specific.

The setting only affects socket close.
Parameters:
- on - whether or not to linger on.
- linger - how long to linger for, if on is true.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
- IllegalArgumentException - if the linger value is negative.
Since: JDK1.1
See Also: Socket.getSoLinger(),

  Enable/disable SO_TIMEOUT with the specified timeout, in milliseconds.

  Enable/disable SO_TIMEOUT with the specified timeout, in
milliseconds. With this option set to a non-zero timeout,
a read() call on the InputStream associated with this Socket
will block for only this amount of time. If the timeout expires,
a java.net.SocketTimeoutException is raised, though the
Socket is still valid. The option must be enabled
prior to entering the blocking operation to have effect. The
timeout must be > 0.
A timeout of zero is interpreted as an infinite timeout.
Parameters:
- timeout - the specified timeout, in milliseconds.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: JDK 1.1
See Also: Socket.getSoTimeout(),

  Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm).

  Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm).
Parameters:
- on - true to enable TCP_NODELAY, false to disable.
Throws:
- SocketException - if there is an error in the underlying protocol, such as a TCP error.
Since: JDK1.1
See Also: Socket.getTcpNoDelay(),

  Sets traffic class or type-of-service octet in the IP header for packets sent from this Socket.

  Sets traffic class or type-of-service octet in the IP header for packets sent from this Socket. As the underlying network implementation may ignore this value applications should consider it a hint.

The tc must be in the range 0 <= tc <= 255 or an IllegalArgumentException will be thrown.

Notes:

For Internet Protocol v4 the value consists of an octet with precedence and TOS fields as detailed in RFC 1349. The TOS field is bitset created by bitwise-or'ing values such the following :-

• IPTOS_LOWCOST (0x02)
• IPTOS_RELIABILITY (0x04)
• IPTOS_THROUGHPUT (0x08)
• IPTOS_LOWDELAY (0x10)

The last low order bit is always ignored as this corresponds to the MBZ (must be zero) bit.

Setting bits in the precedence field may result in a SocketException indicating that the operation is not permitted.

As RFC 1122 section 4.2.4.2 indicates, a compliant TCP implementation should, but is not required to, let application change the TOS field during the lifetime of a connection. So whether the type-of-service field can be changed after the TCP connection has been established depends on the implementation in the underlying platform. Applications should not assume that they can change the TOS field after the connection.

For Internet Protocol v6 tc is the value that would be placed into the sin6_flowinfo field of the IP header.
Parameters:
- tc - an int value for the bitset.
Throws:
- SocketException - if there is an error setting the traffic class or type-of-service
Since: 1.4
See Also: Socket.getTrafficClass(),

  Places the input stream for this socket at "end of stream".

  Places the input stream for this socket at "end of stream". Any data sent to the input stream side of the socket is acknowledged and then silently discarded.

If you read from a socket input stream after invoking shutdownInput() on the socket, the stream will return EOF.
Throws:
- IOException - if an I/O error occurs when shutting down this socket.
Since: 1.3
See Also: Socket.shutdownOutput(), Socket.close(), Socket.setSoLinger(boolean, int), Socket.isInputShutdown(),

  Disables the output stream for this socket.

  Disables the output stream for this socket.
For a TCP socket, any previously written data will be sent
followed by TCP's normal connection termination sequence.

If you write to a socket output stream after invoking
shutdownOutput() on the socket, the stream will throw
an IOException.
Throws:
- IOException - if an I/O error occurs when shutting down this socket.
Since: 1.3
See Also: Socket.shutdownInput(), Socket.close(), Socket.setSoLinger(boolean, int), Socket.isOutputShutdown(),

  Converts this socket to a String.

  Converts this socket to a String.
Returns: a string representation of this socket.