socket.java

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     * @exception  IOException  if an I/O error occurs when creating the
     *               output stream or if the socket is not connected.
     * @revised 1.4
     * @spec JSR-51
     */
    public OutputStream getOutputStream() throws IOException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	if (!isConnected())
	    throw new SocketException("Socket is not connected");
	if (isOutputShutdown())
	    throw new SocketException("Socket output is shutdown");
	final Socket s = this;
	OutputStream os = null;
	try {
	    os = (OutputStream)
		AccessController.doPrivileged(new PrivilegedExceptionAction() {
		    public Object run() throws IOException {
			return impl.getOutputStream();
		    }
		});
	} catch (java.security.PrivilegedActionException e) {
	    throw (IOException) e.getException();
	}
	return os;
    }

    /**
     * Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm).
     *
     * @param on <code>true</code> to enable TCP_NODELAY, 
     * <code>false</code> to disable.
     *
     * @exception SocketException if there is an error 
     * in the underlying protocol, such as a TCP error.
     * 
     * @since   JDK1.1
     *
     * @see #getTcpNoDelay()
     */
    public void setTcpNoDelay(boolean on) throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	getImpl().setOption(SocketOptions.TCP_NODELAY, new Boolean(on));
    }

    /**
     * Tests if TCP_NODELAY is enabled.
     *
     * @return a <code>boolean</code> indicating whether or not TCP_NODELAY is enabled.
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error. 
     * @since   JDK1.1
     * @see #setTcpNoDelay(boolean)
     */
    public boolean getTcpNoDelay() throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	return ((Boolean) getImpl().getOption(SocketOptions.TCP_NODELAY)).booleanValue();
    }

    /**
     * Enable/disable SO_LINGER with the specified linger time in seconds. 
     * The maximum timeout value is platform specific.
     *
     * The setting only affects socket close.
     * 
     * @param on     whether or not to linger on.
     * @param linger how long to linger for, if on is true.
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error. 
     * @exception IllegalArgumentException if the linger value is negative.
     * @since JDK1.1
     * @see #getSoLinger()
     */
    public void setSoLinger(boolean on, int linger) throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	if (!on) {
	    getImpl().setOption(SocketOptions.SO_LINGER, new Boolean(on));
	} else {
	    if (linger < 0) {
		throw new IllegalArgumentException("invalid value for SO_LINGER");
	    }
            if (linger > 65535)
                linger = 65535;
	    getImpl().setOption(SocketOptions.SO_LINGER, new Integer(linger));
	}
    }

    /**
     * Returns setting for SO_LINGER. -1 returns implies that the
     * option is disabled.
     *
     * The setting only affects socket close.
     *
     * @return the setting for SO_LINGER.
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error. 
     * @since   JDK1.1
     * @see #setSoLinger(boolean, int)
     */
    public int getSoLinger() throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	Object o = getImpl().getOption(SocketOptions.SO_LINGER);
	if (o instanceof Integer) {
	    return ((Integer) o).intValue();
	} else {
	    return -1;
	}
    }

    /**
     * Send one byte of urgent data on the socket. The byte to be sent is the lowest eight
     * bits of the data parameter. The urgent byte is
     * sent after any preceding writes to the socket OutputStream
     * and before any future writes to the OutputStream.
     * @param data The byte of data to send
     * @exception IOException if there is an error
     *  sending the data.
     * @since 1.4
     */
    public void sendUrgentData (int data) throws IOException  {
        if (!getImpl().supportsUrgentData ()) {
            throw new SocketException ("Urgent data not supported");
        }
        getImpl().sendUrgentData (data);
    }

    /**
     * Enable/disable OOBINLINE (receipt of TCP urgent data)
     *
     * By default, this option is disabled and TCP urgent data received on a 
     * socket is silently discarded. If the user wishes to receive urgent data, then
     * this option must be enabled. When enabled, urgent data is received
     * inline with normal data. 
     * <p>
     * Note, only limited support is provided for handling incoming urgent 
     * data. In particular, no notification of incoming urgent data is provided 
     * and there is no capability to distinguish between normal data and urgent
     * data unless provided by a higher level protocol.
     *
     * @param on <code>true</code> to enable OOBINLINE, 
     * <code>false</code> to disable.
     *
     * @exception SocketException if there is an error 
     * in the underlying protocol, such as a TCP error.
     * 
     * @since   1.4
     *
     * @see #getOOBInline()
     */
    public void setOOBInline(boolean on) throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	getImpl().setOption(SocketOptions.SO_OOBINLINE, new Boolean(on));
    }

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

    /**
     *  Enable/disable SO_TIMEOUT with the specified timeout, in
     *  milliseconds.  With this option set to a non-zero timeout,
     *  a read() call on the InputStream associated with this Socket
     *  will block for only this amount of time.  If the timeout expires,
     *  a <B>java.net.SocketTimeoutException</B> is raised, though the
     *  Socket 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   JDK 1.1
     * @see #getSoTimeout()
     */
    public synchronized void setSoTimeout(int timeout) throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	if (timeout < 0)
	  throw new IllegalArgumentException("timeout can't be negative");

	getImpl().setOption(SocketOptions.SO_TIMEOUT, new Integer(timeout));
    }

    /**
     * Returns setting for SO_TIMEOUT.  0 returns implies that the
     * option is disabled (i.e., timeout of infinity).
     * @return the setting for SO_TIMEOUT
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error. 
     * @since   JDK1.1
     * @see #setSoTimeout(int)
     */
    public synchronized int getSoTimeout() throws SocketException {
	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;
	}
    }

    /**
     * Sets the SO_SNDBUF option to the specified value for this
     * <tt>Socket</tt>. The SO_SNDBUF option is used by the platform's
     * networking code as a hint for the size to set
     * the underlying network I/O buffers.
     *
     * <p>Because SO_SNDBUF is a hint, applications that want to
     * verify what size the buffers were set to should call
     * {@link #getSendBufferSize()}.
     *
     * @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 send buffer
     * size. This value must be greater than 0.
     *
     * @exception IllegalArgumentException if the 
     * value is 0 or is negative.
     *
     * @see #getSendBufferSize()
     * @since 1.2
     */
    public synchronized void setSendBufferSize(int size)
    throws SocketException{
	if (!(size > 0)) {
	    throw new IllegalArgumentException("negative send size");
	}
	if (isClosed())
	    throw new SocketException("Socket is closed");
	getImpl().setOption(SocketOptions.SO_SNDBUF, new Integer(size));
    }

    /**
     * Get value of the SO_SNDBUF option for this <tt>Socket</tt>, 
     * that is the buffer size used by the platform 
     * for output on this <tt>Socket</tt>.
     * @return the value of the SO_SNDBUF option for this <tt>Socket</tt>.
     *
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error. 
     *
     * @see #setSendBufferSize(int)
     * @since 1.2
     */
    public synchronized int getSendBufferSize() throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
	int result = 0;
	Object o = getImpl().getOption(SocketOptions.SO_SNDBUF);
	if (o instanceof Integer) {
	    result = ((Integer)o).intValue();
	}
	return result;
    }

    /**
     * Sets the SO_RCVBUF option to the specified value for this
     * <tt>Socket</tt>. The SO_RCVBUF option is used by the platform's
     * networking code as a hint for the size to set
     * the underlying network I/O buffers.
     *
     * <p>Increasing the receive buffer size can increase the performance of
     * network I/O for high-volume connection, while decreasing it can
     * help reduce the backlog of incoming data. 
     *
     * <p>Because SO_RCVBUF is a hint, applications that want to
     * verify what size the buffers were set to should call
     * {@link #getReceiveBufferSize()}.
     *
     * <p>The value of SO_RCVBUF is also used to set the TCP receive window
     * that is advertized to the remote peer. Generally, the window size
     * can be modified at any time when a socket is connected. However, if
     * a receive window larger than 64K is required then this must be requested
     * <B>before</B> the socket is connected to the remote peer. There are two
     * cases to be aware of:<p>
     * <ol>
     * <li>For sockets accepted from a ServerSocket, this must be done by calling
     * {@link ServerSocket#setReceiveBufferSize(int)} before the ServerSocket 
     * is bound to a local address.<p></li>
     * <li>For client sockets, setReceiveBufferSize() must be called before
     * connecting the socket to its remote peer.<p></li></ol>
     * @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.
     *
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error.
     * 
     * @see #getReceiveBufferSize()
     * @see ServerSocket#setReceiveBufferSize(int)
     * @since 1.2
     */
    public synchronized void setReceiveBufferSize(int size)
    throws SocketException{
	if (size <= 0) {
	    throw new IllegalArgumentException("invalid 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>Socket</tt>, 
     * that is the buffer size used by the platform for 
     * input on this <tt>Socket</tt>.
     *
     * @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 1.2
     */
    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;
    }

    /**
     * Enable/disable SO_KEEPALIVE.
     * 
     * @param on     whether or not to have socket keep alive turned on.
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error. 
     * @since 1.3 
     * @see #getKeepAlive()
     */
    public void setKeepAlive(boolean on) throws SocketException {
	if (isClosed())
	    throw new SocketException("Socket is closed");
        getImpl().setOption(SocketOptions.SO_KEEPALIVE, new Boolean(on));
    }

    /**
     * Tests if SO_KEEPALIVE is enabled.
     *