All Implemented Interfaces:

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 Summary

  Fields

  The IP address of the remote end of this socket.

  The file descriptor object for this socket.

  protected int

  The local port number to which this socket is connected.

  protected int

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

  Fields declared in interface java.net.SocketOptions

  IP_MULTICAST_IF, IP_MULTICAST_IF2, IP_MULTICAST_LOOP, IP_TOS, SO_BINDADDR, SO_BROADCAST, SO_KEEPALIVE, SO_LINGER, SO_OOBINLINE, SO_RCVBUF, SO_REUSEADDR, SO_REUSEPORT, SO_SNDBUF, SO_TIMEOUT, TCP_NODELAY

• Constructor Summary

  Constructors

  Initialize a new instance of this class

• Method Summary

  protected abstract void

  protected abstract int

  available()

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

  protected abstract void

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

  protected abstract void

  close()

  protected abstract void

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

  protected abstract void

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

  protected abstract void

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

  protected abstract void

  create(boolean stream)

  Creates either a stream or a datagram socket.

  Returns the value of this socket's fd field.

  Returns the value of this socket's address field.

  Returns an input stream for this socket.

  protected int

  Returns the value of this socket's localport field.

  protected <T> T

  Called to get a socket option.

  Returns an output stream for this socket.

  protected int

  getPort()

  Returns the value of this socket's port field.

  protected abstract void

  listen(int backlog)

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

  protected abstract void

  sendUrgentData(int data)

  Send one byte of urgent data on the socket.

  protected <T> void

  Called to set a socket option.

  protected void

  setPerformancePreferences(int connectionTime, int latency, int bandwidth)

  Sets performance preferences for this socket.

  protected void

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

  protected void

  Disables the output stream for this socket.

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

  protected boolean

  Returns whether or not this SocketImpl supports sending urgent data.

  toString()

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

• Field Details

  • fd

    The file descriptor object for this socket.

  • address

    The IP address of the remote end of this socket.

  • port

    protected int port

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

  • localport

    protected int localport

    The local port number to which this socket is connected.

• Constructor Details

  • SocketImpl

    public SocketImpl()

    Initialize a new instance of this class

• Method Details

  • 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.

  • 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.

  • connect

    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.

  • connect

    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

  • bind

    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.

  • 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.

  • accept

    Accepts a connection.

    Parameters:

    s - the accepted connection.

    Throws:

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

  • getInputStream

    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.

  • getOutputStream

    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.

  • 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.

  • close

    protected abstract void close() throws IOException

    Closes this socket.

    Throws:

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

  • 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)

  • 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)

  • getFileDescriptor

    Returns the value of this socket's fd field.

    Returns:

    the value of this socket's fd field.

    See Also:

    • fd

  • getInetAddress

    Returns the value of this socket's address field.

    Returns:

    the value of this socket's address field.

    See Also:

    • address

  • 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

  • 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

  • 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

  • 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

  • toString

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

    Overrides:

    toString in class Object

    Returns:

    a string representation of this socket.

  • 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

    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

  • getOption

    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

  • 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