serversocket.java

This is a resource based on j2me embedded,if you dont understand,you can connection with me .

     * @return  the port number to which this socket is listening or
     *	        -1 if the socket is not bound yet.
     */
    public int getLocalPort() {
	if (!isBound())
	    return -1;
	try {
	    return getImpl().getLocalPort();
	} catch (SocketException e) {
	    // nothing
	    // If we're bound, the the impl has been created
	    // so we shouldn't get here
	}
	return -1;
    }

    /**
     * Returns the address of the endpoint this socket is bound to, or
     * <code>null</code> if it is not bound yet.
     *
     * @return a <code>SocketAddress</code> representing the local endpoint of this
     *	       socket, or <code>null</code> if it is not bound yet.
     * @see #getInetAddress()
     * @see #getLocalPort()
     * @see #bind(SocketAddress)
     * @since 1.4
     */

    public SocketAddress getLocalSocketAddress() {
	if (!isBound())
	    return null;
	return new InetSocketAddress(getInetAddress(), getLocalPort());
    }

    /**
     * Listens for a connection to be made to this socket and accepts 
     * it. The method blocks until a connection is made. 
     *
     * <p>A new Socket <code>s</code> is created and, if there 
     * is a security manager, 
     * the security manager's <code>checkAccept</code> method is called
     * with <code>s.getInetAddress().getHostAddress()</code> and
     * <code>s.getPort()</code>
     * as its arguments to ensure the operation is allowed. 
     * This could result in a SecurityException.
     * 
     * @exception  IOException  if an I/O error occurs when waiting for a
     *               connection.
     * @exception  SecurityException  if a security manager exists and its  
     *             <code>checkListen</code> method doesn't allow the operation.
     * @exception  SocketTimeoutException if a timeout was previously set with setSoTimeout and
     *             the timeout has been reached.
     *
     * @return the new Socket
     * @see SecurityManager#checkAccept
     * @revised 1.4
     * @spec JSR-51
     */
    public Socket accept() throws IOException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	if (!isBound())
	    throw new SocketException("Socket is not bound yet");
	Socket s = new Socket((SocketImpl) null);
	implAccept(s);
	return s;
    }

    /**
     * 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 <i>empty</i> FooSocket.  On
     * return from implAccept the FooSocket will be connected to a client.
     *
     * @param s the Socket
     * @throws IOException if an I/O error occurs when waiting 
     * for a connection.
     * @since   JDK1.1
     * @revised 1.4
     * @spec JSR-51
     */
    protected final void implAccept(Socket s) throws IOException {
	SocketImpl si = null;
	try {
	    if (s.impl == null)
	      s.setImpl();
	    si = s.impl;	    
	    s.impl = null;
	    si.address = new InetAddress();
	    si.fd = new FileDescriptor();
	    getImpl().accept(si);
 	    
	    SecurityManager security = System.getSecurityManager();
	    if (security != null) {
		security.checkAccept(si.getInetAddress().getHostAddress(),
				     si.getPort());
	    }
	} catch (IOException e) {
	    if (si != null)
		si.reset();
            s.impl = si;
	    throw e;
	} catch (SecurityException e) {
	    if (si != null)
		si.reset();
	    s.impl = si;
	    throw e;
	}
	s.impl = si;
	s.postAccept();
    }

    /**
     * Closes this socket. 
     * 
     * Any thread currently blocked in {@link #accept()} will throw
     * a {@link SocketException}.
     *
     * @exception  IOException  if an I/O error occurs when closing the socket.
     * @revised 1.4
     * @spec JSR-51
     */
    public void close() throws IOException {
	synchronized(closeLock) {
	    if (isClosed())
		return;
	    if (created)
		impl.close();
	    closed = true;
	}
    }

    /**
     * Returns the binding state of the ServerSocket.
     *
     * @return true if the ServerSocket succesfuly bound to an address
     * @since 1.4
     */
    public boolean isBound() {
	// Before 1.3 ServerSockets were always bound during creation
	return bound || oldImpl;
    }

    /**
     * Returns the closed state of the ServerSocket.
     *
     * @return true if the socket has been closed
     * @since 1.4
     */
    public boolean isClosed() {
	synchronized(closeLock) {
	    return closed;
	}
    }

    /**
     * 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 <B>java.net.SocketTimeoutException</B> is raised, though the
     * ServerSocket is still valid.  The option <B>must</B> 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.  
     * @param timeout the specified timeout, in milliseconds
     * @exception SocketException if there is an error in 
     * the underlying protocol, such as a TCP error. 
     * @since   JDK1.1
     * @see #getSoTimeout()
     */
    public synchronized void setSoTimeout(int timeout) throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	getImpl().setOption(SocketOptions.SO_TIMEOUT, new Integer(timeout));
    }

    /** 
     * Retrive setting for SO_TIMEOUT.  0 returns implies that the
     * option is disabled (i.e., timeout of infinity).
     * @return the SO_TIMEOUT value
     * @exception IOException if an I/O error occurs
     * @since   JDK1.1
     * @see #setSoTimeout(int)
     */
    public synchronized int getSoTimeout() throws IOException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	Object o = getImpl().getOption(SocketOptions.SO_TIMEOUT);
	/* extra type safety */
	if (o instanceof Integer) {
	    return ((Integer) o).intValue();
	} else {
	    return 0;
	}
    }

    /**
     * Enable/disable the SO_REUSEADDR socket option.
     * <p>
     * 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 <tt>TIME_WAIT</tt> state 
     * or <tt>2MSL</tt> wait state).
     * For applications using a well known socket address or port 
     * it may not be possible to bind a socket to the required
     * <tt>SocketAddress</tt> if there is a connection in the
     * timeout state involving the socket address or port. 
     * <p>
     * Enabling <tt>SO_REUSEADDR</tt> prior to binding the socket
     * using {@link #bind(SocketAddress)} allows the socket to be
     * bound even though a previous connection is in a timeout
     * state.
     * <p>
     * When a <tt>ServerSocket</tt> is created the initial setting
     * of <tt>SO_REUSEADDR</tt> is not defined. Applications can
     * use {@link getReuseAddress()} to determine the initial 
     * setting of <tt>SO_REUSEADDR</tt>. 
     * <p>
     * The behaviour when <tt>SO_REUSEADDR</tt> is enabled or
     * disabled after a socket is bound (See {@link #isBound()})
     * is not defined.
     * 
     * @param on  whether to enable or disable the socket option
     * @exception SocketException if an error occurs enabling or
     *            disabling the <tt>SO_RESUEADDR</tt> socket option,
     *		  or the socket is closed.
     * @since 1.4
     * @see #getReuseAddress()     
     * @see #bind(SocketAddress)
     * @see #isBound()
     * @see #isClosed()
     */     
    public void setReuseAddress(boolean on) throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
        getImpl().setOption(SocketOptions.SO_REUSEADDR, new Boolean(on));
    }

    /**
     * Tests if SO_REUSEADDR is enabled.
     *
     * @return a <code>boolean</code> indicating whether or not SO_REUSEADDR is enabled.
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error. 
     * @since   1.4
     * @see #setReuseAddress(boolean)
     */
    public boolean getReuseAddress() throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	return ((Boolean) (getImpl().getOption(SocketOptions.SO_REUSEADDR))).booleanValue();
    }

    /**
     * Returns the implementation address and implementation port of 
     * this socket as a <code>String</code>.
     *
     * @return  a string representation of this socket.
     */
    public String toString() {
	if (!isBound())
	    return "ServerSocket[unbound]";
	return "ServerSocket[addr=" + impl.getInetAddress() + 
		",port=" + impl.getPort() + 
		",localport=" + impl.getLocalPort()  + "]";
    }

    void setBound() {
	bound = true;
    }

    void setCreated() {
	created = true;
    }

    /**
     * The factory for all server sockets.
     */
    private static SocketImplFactory factory;

    /**
     * Sets the server socket implementation factory for the 
     * application. The factory can be specified only once. 
     * <p>
     * When an application creates a new server socket, the socket 
     * implementation factory's <code>createSocketImpl</code> method is 
     * called to create the actual socket implementation. 
     * <p>
     * If there is a security manager, this method first calls
     * the security manager's <code>checkSetFactory</code> method 
     * to ensure the operation is allowed. 
     * This could result in a SecurityException.
     *
     * @param      fac   the desired factory.
     * @exception  IOException  if an I/O error occurs when setting the
     *               socket factory.
     * @exception  SocketException  if the factory has already been defined.
     * @exception  SecurityException  if a security manager exists and its  
     *             <code>checkSetFactory</code> method doesn't allow the operation.
     * @see        java.net.SocketImplFactory#createSocketImpl()
     * @see        SecurityManager#checkSetFactory
     */
    public static synchronized void setSocketFactory(SocketImplFactory fac) throws IOException {
	if (factory != null) {
	    throw new SocketException("factory already defined");
	}
	SecurityManager security = System.getSecurityManager();
	if (security != null) {
	    security.checkSetFactory();
	}
	factory = fac;
    }

    /**
     * Sets a default proposed value for the SO_RCVBUF option for sockets 
     * accepted from this <tt>ServerSocket</tt>. The value actually set 
     * in the accepted socket must be determined by calling 
     * {@link Socket#getReceiveBufferSize()} after the socket 
     * is returned by {@link #accept()}. 
     * <p>
     * The value of SO_RCVBUF is used both to set the size of the internal
     * socket receive buffer, and to set the size of the TCP receive window
     * that is advertized to the remote peer.
     * <p>
     * It is possible to change the value subsequently, by calling 
     * {@link Socket#setReceiveBufferSize(int)}. However, if the application 
     * wishes to allow a receive window larger than 64K bytes, as defined by RFC1323
     * then the proposed value must be set in the ServerSocket <B>before</B> 
     * it is bound to a local address. This implies, that the ServerSocket must be 
     * created with the no-argument constructor, then setReceiveBufferSize() must 
     * be called and lastly the ServerSocket is bound to an address by calling bind(). 
     * <p>
     * Failure to do this will not cause an error, and the buffer size may be set to the
     * requested value but the TCP receive window in sockets accepted from 
     * this ServerSocket will be no larger than 64K bytes.
     *
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error. 
     *
     * @param size the size to which to set the receive buffer
     * size. This value must be greater than 0.
     *
     * @exception IllegalArgumentException if the 
     * value is 0 or is negative.
     *
     * @since 1.4
     * @see #getReceiveBufferSize
     */
     public synchronized void setReceiveBufferSize (int size) throws SocketException {
	if (!(size > 0)) {
	    throw new IllegalArgumentException("negative receive size");
	}
	if (isClosed())
	    throw new SocketException("Socket is closed");
	getImpl().setOption(SocketOptions.SO_RCVBUF, new Integer(size));
    }

    /**
     * Gets the value of the SO_RCVBUF option for this <tt>ServerSocket</tt>, 
     * that is the proposed buffer size that will be used for Sockets accepted
     * from this <tt>ServerSocket</tt>.
     * 
     * <p>Note, the value actually set in the accepted socket is determined by
     * calling {@link Socket#getReceiveBufferSize()}.
     * @return the value of the SO_RCVBUF option for this <tt>Socket</tt>.
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error. 
     * @see #setReceiveBufferSize(int)
     * @since 1.4
     */
    public synchronized int getReceiveBufferSize()
    throws SocketException{
	if (isClosed())
	    throw new SocketException("Socket is closed");
	int result = 0;
	Object o = getImpl().getOption(SocketOptions.SO_RCVBUF);
	if (o instanceof Integer) {
	    result = ((Integer)o).intValue();
	}
	return result;
    }
}