Package Summary Overview Summary

### class:SocketImpl [NONE]
All Implemented Interfaces: `SocketOptions` public abstract class SocketImpl extends Object implements SocketOptions The abstract class `SocketImpl` is a common superclass of all classes that actually implement sockets. It is used to create both client and server sockets. Since: 1.0

### field:fd [NONE]
### fd protected FileDescriptor fd The file descriptor object for this socket.

### field:address [NONE]
### address protected InetAddress address The IP address of the remote end of this socket.

### field:port [NONE]
### port protected int port The port number on the remote host to which this socket is connected.

### field:localport [NONE]
### localport protected int localport The local port number to which this socket is connected.

### constructor:SocketImpl() [NONE]
### SocketImpl public SocketImpl() Initialize a new instance of this class

### method:create(boolean) [NONE]
### create protected abstract void create (boolean stream) throws IOException Creates either a stream or a datagram socket. Parameters: `stream` - if `true`, create a stream socket; otherwise, create a datagram socket. Throws: `IOException` - if an I/O error occurs while creating the socket.

### method:connect(java.lang.String,int) [NONE]
### connect protected abstract void connect (String host, int port) throws IOException Connects this socket to the specified port on the named host. Parameters: `host` - the name of the remote host. `port` - the port number. Throws: `IOException` - if an I/O error occurs when connecting to the remote host.

### method:connect(java.net.InetAddress,int) [NONE]
### connect protected abstract void connect (InetAddress address, int port) throws IOException Connects this socket to the specified port number on the specified host. Parameters: `address` - the IP address of the remote host. `port` - the port number. Throws: `IOException` - if an I/O error occurs when attempting a connection.

### method:connect(java.net.SocketAddress,int) [NONE]
### connect protected abstract void connect (SocketAddress address, int timeout) throws IOException Connects this socket to the specified port number on the specified host. A timeout of zero is interpreted as an infinite timeout. The connection will then block until established or an error occurs. Parameters: `address` - the Socket address of the remote host. `timeout` - the timeout value, in milliseconds, or zero for no timeout. Throws: `IOException` - if an I/O error occurs when attempting a connection. Since: 1.4

### method:bind(java.net.InetAddress,int) [NONE]
### bind protected abstract void bind (InetAddress host, int port) throws IOException Binds this socket to the specified local IP address and port number. Parameters: `host` - an IP address that belongs to a local interface. `port` - the port number. Throws: `IOException` - if an I/O error occurs when binding this socket.

### method:listen(int) [NONE]
### listen protected abstract void listen (int backlog) throws IOException Sets the maximum queue length for incoming connection indications (a request to connect) to the `count` argument. If a connection indication arrives when the queue is full, the connection is refused. Parameters: `backlog` - the maximum length of the queue. Throws: `IOException` - if an I/O error occurs when creating the queue.

### method:accept(java.net.SocketImpl) [NONE]
### accept protected abstract void accept (SocketImpl s) throws IOException Accepts a connection. Parameters: `s` - the accepted connection. Throws: `IOException` - if an I/O error occurs when accepting the connection.

### method:getInputStream() [NONE]
### getInputStream protected abstract InputStream getInputStream() throws IOException Returns an input stream for this socket. Returns: a stream for reading from this socket. Throws: `IOException` - if an I/O error occurs when creating the input stream.

### method:getOutputStream() [NONE]
### getOutputStream protected abstract OutputStream getOutputStream() throws IOException Returns an output stream for this socket. Returns: an output stream for writing to this socket. Throws: `IOException` - if an I/O error occurs when creating the output stream.

### method:available() [NONE]
### available protected abstract int available() throws IOException Returns the number of bytes that can be read from this socket without blocking. Returns: the number of bytes that can be read from this socket without blocking. Throws: `IOException` - if an I/O error occurs when determining the number of bytes available.

### method:close() [NONE]
### close protected abstract void close() throws IOException Closes this socket. Throws: `IOException` - if an I/O error occurs when closing this socket.

### method:shutdownInput() [NONE]
### shutdownInput protected void shutdownInput() throws IOException Places the input stream for this socket at "end of stream". Any data sent to this socket is acknowledged and then silently discarded. If you read from a socket input stream after invoking this method on the socket, the stream's `available` method will return 0, and its `read` methods will return `-1` (end of stream). 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)`

### method:shutdownOutput() [NONE]
### shutdownOutput protected void shutdownOutput() throws IOException 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)`

### method:getFileDescriptor() [NONE]
### getFileDescriptor protected FileDescriptor getFileDescriptor() Returns the value of this socket's `fd` field. Returns: the value of this socket's `fd` field. See Also: `fd`

### method:getInetAddress() [NONE]
### getInetAddress protected InetAddress getInetAddress() Returns the value of this socket's `address` field. Returns: the value of this socket's `address` field. See Also: `address`

### method:getPort() [NONE]
### getPort protected int getPort() Returns the value of this socket's `port` field. Returns: the value of this socket's `port` field. See Also: `port`

### method:supportsUrgentData() [NONE]
### supportsUrgentData protected boolean supportsUrgentData() Returns whether or not this SocketImpl supports sending urgent data. By default, false is returned unless the method is overridden in a sub-class Returns: true if urgent data supported Since: 1.4 See Also: `address`

### method:sendUrgentData(int) [NONE]
### sendUrgentData protected abstract void sendUrgentData (int data) throws IOException Send one byte of urgent data on the socket. The byte to be sent is the low eight bits of the parameter Parameters: `data` - The byte of data to send Throws: `IOException` - if there is an error sending the data. Since: 1.4

### method:getLocalPort() [NONE]
### getLocalPort protected int getLocalPort() Returns the value of this socket's `localport` field. Returns: the value of this socket's `localport` field. See Also: `localport`

### method:toString() [NONE]
### toString public String toString() Returns the address and port of this socket as a `String`. Overrides: `toString` in class `Object` Returns: a string representation of this socket.

### method:setPerformancePreferences(int,int,int) [NONE]
### setPerformancePreferences protected void setPerformancePreferences (int connectionTime, int latency, int bandwidth) 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)` . By default, this method does nothing, unless it is overridden in a sub-class. 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 ### setOption protected <T> void setOption (SocketOption<T> name, T value) throws IOException Called to set a socket option. Implementation Requirements: The default implementation of this method first checks that the given socket option `name` is not null, then throws `UnsupportedOperationException` . Subclasses should override this method with an appropriate implementation. Type Parameters: `T` - The type of the socket option value Parameters: `name` - The socket option `value` - The value of the socket option. A value of `null` may be valid for some options. Throws: `UnsupportedOperationException` - if the SocketImpl does not support the option `IllegalArgumentException` - if the value is not valid for the option `IOException` - if an I/O error occurs, or if the socket is closed `NullPointerException` - if name is `null` Since: 9

### method:getOption(java.net.SocketOption) [NONE]
### getOption protected <T> T getOption (SocketOption<T> name) throws IOException Called to get a socket option. Implementation Requirements: The default implementation of this method first checks that the given socket option `name` is not null, then throws `UnsupportedOperationException` . Subclasses should override this method with an appropriate implementation. Type Parameters: `T` - The type of the socket option value Parameters: `name` - The socket option Returns: the value of the named option Throws: `UnsupportedOperationException` - if the SocketImpl does not support the option `IOException` - if an I/O error occurs, or if the socket is closed `NullPointerException` - if name is `null` Since: 9

### method:supportedOptions() [NONE]
### supportedOptions protected Set<SocketOption<?>> supportedOptions() Returns a set of SocketOptions supported by this impl and by this impl's socket (Socket or ServerSocket) Implementation Requirements: The default implementation of this method returns an empty set. Subclasses should override this method with an appropriate implementation. Returns: a Set of SocketOptions Since: 9