Java Platform 1.2
Beta 4

Class java.net.ServerSocket

java.lang.Object
  |
  +--java.net.ServerSocket

public class ServerSocket
extends Object
This class implements server sockets. A server socket waits for requests to come in over the network. It performs some operation based on that request, and then possibly returns a result to the requester.

The actual work of the server socket is performed by an instance of the SocketImpl class. An application can change the socket factory that creates the socket implementation to configure itself to create sockets appropriate to the local firewall.

Since:
JDK1.0
See Also:
SocketImpl, setSocketFactory(java.net.SocketImplFactory)

Constructor Summary
ServerSocket(int port, int backlog, InetAddress bindAddr)
          Create a server with the specified port, listen backlog, and local IP address to bind to.
ServerSocket(int port, int backlog)
          Creates a server socket and binds it to the specified local port number.
ServerSocket(int port)
          Creates a server socket on a specified port.
 
Method Summary
 Socket accept()
          Listens for a connection to be made to this socket and accepts it.
 void close()
          Closes this socket.
 InetAddress getInetAddress()
          Returns the local address of this server socket.
 int getLocalPort()
          Returns the port on which this socket is listening.
 int getSoTimeout()
          Retrive setting for SO_TIMEOUT. 0 returns implies that the option is disabled (i.e.
protected  void implAccept(Socket s)
          Subclasses of ServerSocket use this method to override accept() to return their own subclass of socket.
static void setSocketFactory(SocketImplFactory fac)
          Sets the server socket implementation factory for the application.
 void setSoTimeout(int timeout)
          Enable/disable SO_TIMEOUT with the specified timeout, in milliseconds.
 String toString()
          Returns the implementation address and implementation port of this socket as a String.
 
Methods inherited from class java.lang.Object
clone , equals , finalize , getClass , hashCode , notify , notifyAll , wait , wait , wait
 

Constructor Detail

ServerSocket

public ServerSocket(int port)
             throws IOException
Creates a server socket on a specified port. A port of 0 creates a socket on any free port.

The maximum queue length for incoming connection indications (a request to connect) is set to 50. If a connection indication arrives when the queue is full, the connection is refused.

If the application has specified a server socket factory, that factory's createSocketImpl method is called to create the actual socket implementation. Otherwise a "plain" socket is created.

Parameters:
port - the port number, or 0 to use any free port.
Throws:
IOException - if an I/O error occurs when opening the socket.
See Also:
SocketImpl, SocketImplFactory.createSocketImpl(), setSocketFactory(java.net.SocketImplFactory)

ServerSocket

public ServerSocket(int port,
                    int backlog)
             throws IOException
Creates a server socket and binds it to the specified local port number. A port number of 0 creates a socket on any free port.

The maximum queue length for incoming connection indications (a request to connect) is set to the backlog parameter. If a connection indication arrives when the queue is full, the connection is refused.

If the application has specified a server socket factory, that factory's createSocketImpl method is called to create the actual socket implementation. Otherwise a "plain" socket is created.

Parameters:
port - the specified port, or 0 to use any free port.
backlog - the maximum length of the queue.
Throws:
IOException - if an I/O error occurs when opening the socket.
See Also:
SocketImpl, SocketImplFactory.createSocketImpl(), setSocketFactory(java.net.SocketImplFactory)

ServerSocket

public ServerSocket(int port,
                    int backlog,
                    InetAddress bindAddr)
             throws IOException
Create a server with the specified port, listen backlog, and local IP address to bind to. The bindAddr argument can be used on a multi-homed host for a ServerSocket that will only accept connect requests to one of its addresses. If bindAddr is null, it will default accepting connections on any/all local addresses. The port must be between 0 and 65535, inclusive.

Parameters:
port - the local TCP port
backlog - the listen backlog
bindAddr - the local InetAddress the server will bind to
See Also:
SocketConstants, SocketOption, SocketImpl, JDK1.1
Method Detail

getInetAddress

public InetAddress getInetAddress()
Returns the local address of this server socket.
Returns:
the address to which this socket is connected, or null if the socket is not yet connected.

getLocalPort

public int getLocalPort()
Returns the port on which this socket is listening.
Returns:
the port number to which this socket is listening.

accept

public Socket accept()
              throws IOException
Listens for a connection to be made to this socket and accepts it. The method blocks until a connection is made.
Throws:
IOException - if an I/O error occurs when waiting for a connection.

implAccept

protected final void implAccept(Socket s)
                         throws IOException
Subclasses of ServerSocket use this method to override accept() to return their own subclass of socket. So a FooServerSocket will typically hand this method an empty FooSocket(). On return from implAccept the FooSocket will be connected to a client.
Since:
JDk1.1

close

public void close()
           throws IOException
Closes this socket.
Throws:
IOException - if an I/O error occurs when closing the socket.

setSoTimeout

public void setSoTimeout(int timeout)
                  throws SocketException
Enable/disable SO_TIMEOUT with the specified timeout, in milliseconds. With this option set to a non-zero timeout, a call to accept() for this ServerSocket will block for only this amount of time. If the timeout expires, a java.io.InterruptedIOException is raised, though the ServerSocket 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.
Since:
JDK1.1

getSoTimeout

public int getSoTimeout()
                 throws IOException
Retrive setting for SO_TIMEOUT. 0 returns implies that the option is disabled (i.e., timeout of infinity).
Since:
JDK1.1

toString

public String toString()
Returns the implementation address and implementation port of this socket as a String.
Returns:
a string representation of this socket.
Overrides:
toString in class Object

setSocketFactory

public static void setSocketFactory(SocketImplFactory fac)
                             throws IOException
Sets the server socket implementation factory for the application. The factory can be specified only once.

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

Parameters:
fac - the desired factory.
Throws:
IOException - if an I/O error occurs when setting the socket factory.
SocketException - if the factory has already been defined.
See Also:
SocketImplFactory.createSocketImpl()

Java Platform 1.2
Beta 4

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