SocketImpl

public abstract class SocketImpl
extends Object implements SocketOptions

java.lang.Object
   ↳ java.net.SocketImpl


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.

A "plain" socket implements these methods exactly as described, without attempting to go through a firewall or proxy.

Summary

Inherited constants

Fields

protected InetAddress address

The IP address of the remote end of this socket.

protected FileDescriptor fd

The file descriptor object for this socket.

protected int localport

The local port number to which this socket is connected.

protected int port

The port number on the remote host to which this socket is connected.

Public constructors

SocketImpl()

Public methods

String toString()

Returns the address and port of this socket as a String.

Protected methods

abstract void accept(SocketImpl s)

Accepts a connection.

abstract int available()

Returns the number of bytes that can be read from this socket without blocking.

abstract void bind(InetAddress host, int port)

Binds this socket to the specified local IP address and port number.

abstract void close()

Closes this socket.

abstract void connect(InetAddress address, int port)

Connects this socket to the specified port number on the specified host.

abstract void connect(SocketAddress address, int timeout)

Connects this socket to the specified port number on the specified host.

abstract void connect(String host, int port)

Connects this socket to the specified port on the named host.

abstract void create(boolean stream)

Creates either a stream or a datagram socket.

FileDescriptor getFileDescriptor()

Returns the value of this socket's fd field.

InetAddress getInetAddress()

Returns the value of this socket's address field.

abstract InputStream getInputStream()

Returns an input stream for this socket.

int getLocalPort()

Returns the value of this socket's localport field.

<T> T getOption(SocketOption<T> name)

Called to get a socket option.

abstract OutputStream getOutputStream()

Returns an output stream for this socket.

int getPort()

Returns the value of this socket's port field.

abstract void listen(int backlog)

Sets the maximum queue length for incoming connection indications (a request to connect) to the count argument.

abstract void sendUrgentData(int data)

Send one byte of urgent data on the socket.

<T> void setOption(SocketOption<T> name, T value)

Called to set a socket option.

void setPerformancePreferences(int connectionTime, int latency, int bandwidth)

Sets performance preferences for this socket.

void shutdownInput()

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

void shutdownOutput()

Disables the output stream for this socket.

Set<SocketOption<?>> supportedOptions()

Returns a set of SocketOptions supported by this impl and by this impl's socket (Socket or ServerSocket)

boolean supportsUrgentData()

Returns whether or not this SocketImpl supports sending urgent data.

Inherited methods

Fields

address

Added in API level 1
protected InetAddress address

The IP address of the remote end of this socket.

fd

Added in API level 1
protected FileDescriptor fd

The file descriptor object for this socket.

localport

Added in API level 1
protected int localport

The local port number to which this socket is connected.

port

Added in API level 1
protected int port

The port number on the remote host to which this socket is connected.

Public constructors

SocketImpl

Added in API level 1
public SocketImpl ()

Public methods

toString

Added in API level 1
public String toString ()

Returns the address and port of this socket as a String.

Returns
String a string representation of this socket.

Protected methods

accept

Added in API level 1
protected abstract void accept (SocketImpl s)

Accepts a connection.

Parameters
s SocketImpl: the accepted connection.

Throws
IOException if an I/O error occurs when accepting the connection.

available

Added in API level 1
protected abstract int available ()

Returns the number of bytes that can be read from this socket without blocking.

Returns
int 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.

bind

Added in API level 1
protected abstract void bind (InetAddress host, 
                int port)

Binds this socket to the specified local IP address and port number.

Parameters
host InetAddress: an IP address that belongs to a local interface.

port int: the port number.

Throws
IOException if an I/O error occurs when binding this socket.

close

Added in API level 1
protected abstract void close ()

Closes this socket.

Throws
IOException if an I/O error occurs when closing this socket.

connect

Added in API level 1
protected abstract void connect (InetAddress address, 
                int port)

Connects this socket to the specified port number on the specified host.

Parameters
address InetAddress: the IP address of the remote host.

port int: the port number.

Throws
IOException if an I/O error occurs when attempting a connection.

connect

Added in API level 1
protected abstract void connect (SocketAddress address, 
                int timeout)

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 SocketAddress: the Socket address of the remote host.

timeout int: the timeout value, in milliseconds, or zero for no timeout.

Throws
IOException if an I/O error occurs when attempting a connection.

connect

Added in API level 1
protected abstract void connect (String host, 
                int port)

Connects this socket to the specified port on the named host.

Parameters
host String: the name of the remote host.

port int: the port number.

Throws
IOException if an I/O error occurs when connecting to the remote host.

create

Added in API level 1
protected abstract void create (boolean stream)

Creates either a stream or a datagram socket.

Parameters
stream boolean: if true, create a stream socket; otherwise, create a datagram socket.

Throws
IOException if an I/O error occurs while creating the socket.

getFileDescriptor

Added in API level 1
protected FileDescriptor getFileDescriptor ()

Returns the value of this socket's fd field.

Returns
FileDescriptor the value of this socket's fd field.

See also:

getInetAddress

Added in API level 1
protected InetAddress getInetAddress ()

Returns the value of this socket's address field.

Returns
InetAddress the value of this socket's address field.

See also:

getInputStream

Added in API level 1
protected abstract InputStream getInputStream ()

Returns an input stream for this socket.

Returns
InputStream a stream for reading from this socket.

Throws
IOException if an I/O error occurs when creating the input stream.

getLocalPort

Added in API level 1
protected int getLocalPort ()

Returns the value of this socket's localport field.

Returns
int the value of this socket's localport field.

See also:

getOption

Added in API level 33
protected T getOption (SocketOption<T> name)

Called to get a socket option.

Parameters
name SocketOption: The socket option

Returns
T 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.

getOutputStream

Added in API level 1
protected abstract OutputStream getOutputStream ()

Returns an output stream for this socket.

Returns
OutputStream an output stream for writing to this socket.

Throws
IOException if an I/O error occurs when creating the output stream.

getPort

Added in API level 1
protected int getPort ()

Returns the value of this socket's port field.

Returns
int the value of this socket's port field.

See also:

listen

Added in API level 1
protected abstract void listen (int backlog)

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 int: the maximum length of the queue.

Throws
IOException if an I/O error occurs when creating the queue.

sendUrgentData

Added in API level 1
protected abstract void sendUrgentData (int data)

Send one byte of urgent data on the socket. The byte to be sent is the low eight bits of the parameter

Parameters
data int: The byte of data to send

Throws
IOException if there is an error sending the data.

setOption

Added in API level 33
protected void setOption (SocketOption<T> name, 
                T value)

Called to set a socket option.

Parameters
name SocketOption: The socket option

value T: 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
IOException if an I/O error occurs, or if the socket is closed.

setPerformancePreferences

Added in API level 1
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 int: An int expressing the relative importance of a short connection time

latency int: An int expressing the relative importance of low latency

bandwidth int: An int expressing the relative importance of high bandwidth

shutdownInput

Added in API level 1
protected void shutdownInput ()

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.

shutdownOutput

Added in API level 1
protected void shutdownOutput ()

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.

supportedOptions

Added in API level 33
protected Set<SocketOption<?>> supportedOptions ()

Returns a set of SocketOptions supported by this impl and by this impl's socket (Socket or ServerSocket)

Returns
Set<SocketOption<?>> a Set of SocketOptions

supportsUrgentData

Added in API level 1
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
boolean true if urgent data supported

See also: