671 lines
21 KiB
Java
671 lines
21 KiB
Java
/* Socket.java -- Client socket implementation
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Copyright (C) 1998, 1999, 2000, 2002 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.net;
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import java.io.*;
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/* Written using on-line Java Platform 1.2 API Specification.
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* Status: I believe all methods are implemented.
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*/
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/**
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* This class models a client site socket. A socket is a TCP/IP endpoint
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* for network communications conceptually similar to a file handle.
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* <p>
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* This class does not actually do any work. Instead, it redirects all of
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* its calls to a socket implementation object which implements the
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* <code>SocketImpl</code> interface. The implementation class is
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* instantiated by factory class that implements the
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* <code>SocketImplFactory interface</code>. A default
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* factory is provided, however the factory may be set by a call to
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* the <code>setSocketImplFactory</code> method. Note that this may only be
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* done once per virtual machine. If a subsequent attempt is made to set the
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* factory, a <code>SocketException</code> will be thrown.
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*
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* @author Aaron M. Renn (arenn@urbanophile.com)
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* @author Per Bothner (bothner@cygnus.com)
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*/
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public class Socket
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{
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// Class Variables
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/**
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* This is the user SocketImplFactory for this class. If this variable is
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* null, a default factory is used.
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*/
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static SocketImplFactory factory;
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// Instance Variables
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/**
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* The implementation object to which calls are redirected
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*/
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SocketImpl impl;
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// Constructors
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/**
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* Initializes a new instance of <code>Socket</code> object without
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* connecting to a remote host. This useful for subclasses of socket that
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* might want this behavior.
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*/
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protected Socket ()
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{
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if (factory != null)
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impl = factory.createSocketImpl();
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else
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impl = new PlainSocketImpl();
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}
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/**
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* Initializes a new instance of <code>Socket</code> object without
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* connecting to a remote host. This is useful for subclasses of socket
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* that might want this behavior.
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* <p>
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* Additionally, this socket will be created using the supplied
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* implementation class instead the default class or one returned by a
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* factory. This value can be <code>null</code>, but if it is, all instance
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* methods in <code>Socket</code> should be overridden because most of them
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* rely on this value being populated.
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*
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* @param impl The <code>SocketImpl</code> to use for this
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* <code>Socket</code>
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*
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* @exception SocketException If an error occurs
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*/
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protected Socket (SocketImpl impl) throws SocketException
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{
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this.impl = impl;
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}
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/**
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* Initializes a new instance of <code>Socket</code> and connects to the
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* hostname and port specified as arguments.
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*
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* @param host The name of the host to connect to
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* @param port The port number to connect to
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*
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* @exception UnknownHostException If the hostname cannot be resolved to a
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* network address.
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* @exception IOException If an error occurs
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*/
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public Socket (String host, int port)
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throws UnknownHostException, IOException
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{
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this(InetAddress.getByName(host), port, null, 0, true);
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}
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/**
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* Initializes a new instance of <code>Socket</code> and connects to the
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* address and port number specified as arguments.
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*
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* @param address The address to connect to
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* @param port The port number to connect to
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*
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* @exception IOException If an error occurs
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*/
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public Socket (InetAddress address, int port)
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throws IOException
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{
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this(address, port, null, 0, true);
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}
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/**
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* Initializes a new instance of <code>Socket</code> that connects to the
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* named host on the specified port and binds to the specified local address
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* and port.
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*
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* @param host The name of the remote host to connect to.
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* @param port The remote port to connect to.
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* @param loadAddr The local address to bind to.
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* @param localPort The local port to bind to.
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*
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* @exception SecurityException If the <code>SecurityManager</code>
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* exists and does not allow a connection to the specified host/port or
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* binding to the specified local host/port.
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* @exception IOException If a connection error occurs.
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*/
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public Socket (String host, int port,
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InetAddress localAddr, int localPort) throws IOException
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{
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this(InetAddress.getByName(host), port, localAddr, localPort, true);
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}
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/**
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* Initializes a new instance of <code>Socket</code> and connects to the
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* address and port number specified as arguments, plus binds to the
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* specified local address and port.
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*
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* @param address The remote address to connect to
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* @param port The remote port to connect to
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* @param localAddr The local address to connect to
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* @param localPort The local port to connect to
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*
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* @exception IOException If an error occurs
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*/
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public Socket (InetAddress address, int port,
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InetAddress localAddr, int localPort) throws IOException
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{
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this(address, port, localAddr, localPort, true);
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}
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/**
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* Initializes a new instance of <code>Socket</code> and connects to the
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* hostname and port specified as arguments. If the stream argument is set
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* to <code>true</code>, then a stream socket is created. If it is
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* <code>false</code>, a datagram socket is created.
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*
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* @param host The name of the host to connect to
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* @param port The port to connect to
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* @param stream <code>true</code> for a stream socket, <code>false</code>
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* for a datagram socket
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*
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* @exception IOException If an error occurs
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*
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* @deprecated Use the <code>DatagramSocket</code> class to create
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* datagram oriented sockets.
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*/
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public Socket (String host, int port, boolean stream) throws IOException
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{
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this(InetAddress.getByName(host), port, null, 0, stream);
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}
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/**
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* Initializes a new instance of <code>Socket</code> and connects to the
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* address and port number specified as arguments. If the stream param is
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* <code>true</code>, a stream socket will be created, otherwise a datagram
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* socket is created.
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*
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* @param host The address to connect to
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* @param port The port number to connect to
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* @param stream <code>true</code> to create a stream socket,
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* <code>false</code> to create a datagram socket.
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*
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* @exception IOException If an error occurs
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*
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* @deprecated Use the <code>DatagramSocket</code> class to create
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* datagram oriented sockets.
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*/
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public Socket (InetAddress host, int port, boolean stream) throws IOException
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{
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this(host, port, null, 0, stream);
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}
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/**
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* This constructor is where the real work takes place. Connect to the
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* specified address and port. Use default local values if not specified,
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* otherwise use the local host and port passed in. Create as stream or
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* datagram based on "stream" argument.
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* <p>
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*
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* @param raddr The remote address to connect to
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* @param rport The remote port to connect to
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* @param laddr The local address to connect to
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* @param lport The local port to connect to
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* @param stream true for a stream socket, false for a datagram socket
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*
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* @exception IOException If an error occurs
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*/
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private Socket(InetAddress raddr, int rport, InetAddress laddr, int lport,
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boolean stream) throws IOException
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{
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this();
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if (impl == null)
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throw new IOException("Cannot initialize Socket implementation");
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SecurityManager sm = System.getSecurityManager();
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if (sm != null)
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sm.checkConnect(raddr.getHostName(), rport);
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impl.create(stream);
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// FIXME: JCL p. 1586 says if localPort is unspecified, bind to any port,
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// i.e. '0' and if localAddr is unspecified, use getLocalAddress() as
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// that default. JDK 1.2 doc infers not to do a bind.
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if (laddr != null)
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impl.bind(laddr, lport);
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if (raddr != null)
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impl.connect(raddr, rport);
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}
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/**
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* Returns the address of the remote end of the socket. If this socket
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* is not connected, then <code>null</code> is returned.
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*
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* @return The remote address this socket is connected to
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*/
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public InetAddress getInetAddress ()
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{
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if (impl != null)
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return impl.getInetAddress();
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return null;
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}
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/**
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* Returns the local address to which this socket is bound. If this socket
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* is not connected, then <code>null</code> is returned.
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*
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* @return The local address
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*/
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public InetAddress getLocalAddress ()
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{
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if (impl == null)
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return null;
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InetAddress addr = null;
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try
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{
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addr = (InetAddress)impl.getOption(SocketOptions.SO_BINDADDR);
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}
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catch(SocketException e)
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{
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// (hopefully) shouldn't happen
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// throw new java.lang.InternalError
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// ("Error in PlainSocketImpl.getOption");
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return null;
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}
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// FIXME: According to libgcj, checkConnect() is supposed to be called
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// before performing this operation. Problems: 1) We don't have the
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// addr until after we do it, so we do a post check. 2). The docs I
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// see don't require this in the Socket case, only DatagramSocket, but
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// we'll assume they mean both.
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SecurityManager sm = System.getSecurityManager();
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if (sm != null)
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sm.checkConnect(addr.getHostName(), getLocalPort());
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return addr;
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}
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/**
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* Returns the port number of the remote end of the socket connection. If
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* this socket is not connected, then -1 is returned.
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*
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* @return The remote port this socket is connected to
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*/
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public int getPort ()
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{
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if (impl != null)
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return impl.getPort();
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return -1;
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}
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/**
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* Returns the local port number to which this socket is bound. If this
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* socket is not connected, then -1 is returned.
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*
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* @return The local port
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*/
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public int getLocalPort ()
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{
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if (impl != null)
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return impl.getLocalPort();
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return -1;
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}
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/**
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* Returns an InputStream for reading from this socket.
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*
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* @return The InputStream object
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*
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* @exception IOException If an error occurs or Socket is not connected
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*/
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public InputStream getInputStream () throws IOException
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{
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if (impl != null)
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return(impl.getInputStream());
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throw new IOException("Not connected");
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}
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/**
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* Returns an OutputStream for writing to this socket.
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*
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* @return The OutputStream object
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*
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* @exception IOException If an error occurs or Socket is not connected
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*/
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public OutputStream getOutputStream () throws IOException
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{
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if (impl != null)
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return impl.getOutputStream();
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throw new IOException("Not connected");
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}
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/**
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* Sets the TCP_NODELAY option on the socket.
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*
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* @param on true to enable, false to disable
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*
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* @exception SocketException If an error occurs or Socket is not connected
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*/
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public void setTcpNoDelay (boolean on) throws SocketException
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{
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if (impl == null)
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throw new SocketException("Not connected");
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impl.setOption(SocketOptions.TCP_NODELAY, new Boolean(on));
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}
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/**
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* Tests whether or not the TCP_NODELAY option is set on the socket.
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* Returns true if enabled, false if disabled. When on it disables the
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* Nagle algorithm which means that packets are always send immediatly and
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* never merged together to reduce network trafic.
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*
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* @return Whether or not TCP_NODELAY is set
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*
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* @exception SocketException If an error occurs or Socket not connected
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*/
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public boolean getTcpNoDelay() throws SocketException
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{
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if (impl == null)
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throw new SocketException("Not connected");
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Object on = impl.getOption(SocketOptions.TCP_NODELAY);
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if (on instanceof Boolean)
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return(((Boolean)on).booleanValue());
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else
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throw new SocketException("Internal Error");
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}
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/**
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* Sets the value of the SO_LINGER option on the socket. If the
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* SO_LINGER option is set on a socket and there is still data waiting to
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* be sent when the socket is closed, then the close operation will block
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* until either that data is delivered or until the timeout period
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* expires. The linger interval is specified in hundreths of a second
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* (platform specific?)
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*
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* @param on true to enable SO_LINGER, false to disable
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* @param linger The SO_LINGER timeout in hundreths of a second or -1 if
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* SO_LINGER not set.
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*
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* @exception SocketException If an error occurs or Socket not connected
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*/
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public void setSoLinger(boolean on, int linger) throws SocketException
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{
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if (impl == null)
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throw new SocketException("No socket created");
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if (on == true)
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{
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if (linger < 0)
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throw new IllegalArgumentException("SO_LINGER must be >= 0");
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if (linger > 65535)
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linger = 65535;
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impl.setOption(SocketOptions.SO_LINGER, new Integer(linger));
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}
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else
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{
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impl.setOption(SocketOptions.SO_LINGER, new Boolean(false));
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}
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}
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/**
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* Returns the value of the SO_LINGER option on the socket. If the
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* SO_LINGER option is set on a socket and there is still data waiting to
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* be sent when the socket is closed, then the close operation will block
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* until either that data is delivered or until the timeout period
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* expires. This method either returns the timeouts (in hundredths of
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* of a second (platform specific?)) if SO_LINGER is set, or -1 if
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* SO_LINGER is not set.
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*
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* @return The SO_LINGER timeout in hundreths of a second or -1
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* if SO_LINGER not set
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*
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* @exception SocketException If an error occurs or Socket is not connected
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*/
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public int getSoLinger() throws SocketException
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{
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if (impl == null)
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throw new SocketException("Not connected");
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Object linger = impl.getOption(SocketOptions.SO_LINGER);
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if (linger instanceof Integer)
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return(((Integer)linger).intValue());
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else
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return -1;
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}
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/**
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* Sets the value of the SO_TIMEOUT option on the socket. If this value
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* is set, and an read/write is performed that does not complete within
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* the timeout period, a short count is returned (or an EWOULDBLOCK signal
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* would be sent in Unix if no data had been read). A value of 0 for
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* this option implies that there is no timeout (ie, operations will
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* block forever). On systems that have separate read and write timeout
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* values, this method returns the read timeout. This
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* value is in thousandths of a second (****????*****)
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*
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* @param timeout The length of the timeout in thousandth's of a second or
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* 0 if not set
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*
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* @exception SocketException If an error occurs or Socket not connected
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*/
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public synchronized void setSoTimeout (int timeout) throws SocketException
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{
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if (impl == null)
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throw new SocketException("Not connected");
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if (timeout < 0)
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throw new IllegalArgumentException("SO_TIMEOUT value must be >= 0");
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impl.setOption(SocketOptions.SO_TIMEOUT, new Integer(timeout));
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}
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/**
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* Returns the value of the SO_TIMEOUT option on the socket. If this value
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* is set, and an read/write is performed that does not complete within
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* the timeout period, a short count is returned (or an EWOULDBLOCK signal
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* would be sent in Unix if no data had been read). A value of 0 for
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* this option implies that there is no timeout (ie, operations will
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* block forever). On systems that have separate read and write timeout
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* values, this method returns the read timeout. This
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* value is in thousandths of a second (implementation specific?).
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*
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* @return The length of the timeout in thousandth's of a second or 0
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* if not set
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*
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* @exception SocketException If an error occurs or Socket not connected
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*/
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public synchronized int getSoTimeout () throws SocketException
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{
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if (impl == null)
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throw new SocketException("Not connected");
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Object timeout = impl.getOption(SocketOptions.SO_TIMEOUT);
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if (timeout instanceof Integer)
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return(((Integer)timeout).intValue());
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else
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return 0;
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}
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/**
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* This method sets the value for the system level socket option
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* SO_SNDBUF to the specified value. Note that valid values for this
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* option are specific to a given operating system.
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*
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* @param size The new send buffer size.
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*
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* @exception SocketException If an error occurs or Socket not connected
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*
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* @since Java 1.2
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*/
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public void setSendBufferSize (int size) throws SocketException
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{
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if (impl == null)
|
|
throw new SocketException("Not connected");
|
|
|
|
if (size <= 0)
|
|
throw new IllegalArgumentException("SO_SNDBUF value must be > 0");
|
|
|
|
impl.setOption(SocketOptions.SO_SNDBUF, new Integer(size));
|
|
}
|
|
|
|
/**
|
|
* This method returns the value of the system level socket option
|
|
* SO_SNDBUF, which is used by the operating system to tune buffer
|
|
* sizes for data transfers.
|
|
*
|
|
* @return The send buffer size.
|
|
*
|
|
* @exception SocketException If an error occurs or socket not connected
|
|
*
|
|
* @since Java 1.2
|
|
*/
|
|
public int getSendBufferSize () throws SocketException
|
|
{
|
|
if (impl == null)
|
|
throw new SocketException("Not connected");
|
|
|
|
Object buf = impl.getOption(SocketOptions.SO_SNDBUF);
|
|
|
|
if (buf instanceof Integer)
|
|
return(((Integer)buf).intValue());
|
|
else
|
|
throw new SocketException("Internal Error: Unexpected type");
|
|
}
|
|
|
|
/**
|
|
* This method sets the value for the system level socket option
|
|
* SO_RCVBUF to the specified value. Note that valid values for this
|
|
* option are specific to a given operating system.
|
|
*
|
|
* @param size The new receive buffer size.
|
|
*
|
|
* @exception SocketException If an error occurs or Socket is not connected
|
|
*
|
|
* @since Java 1.2
|
|
*/
|
|
public void setReceiveBufferSize (int size) throws SocketException
|
|
{
|
|
if (impl == null)
|
|
throw new SocketException("Not connected");
|
|
|
|
if (size <= 0)
|
|
throw new IllegalArgumentException("SO_RCVBUF value must be > 0");
|
|
|
|
impl.setOption(SocketOptions.SO_RCVBUF, new Integer(size));
|
|
}
|
|
|
|
/**
|
|
* This method returns the value of the system level socket option
|
|
* SO_RCVBUF, which is used by the operating system to tune buffer
|
|
* sizes for data transfers.
|
|
*
|
|
* @return The receive buffer size.
|
|
*
|
|
* @exception SocketException If an error occurs or Socket is not connected
|
|
*
|
|
* @since Java 1.2
|
|
*/
|
|
public int getReceiveBufferSize () throws SocketException
|
|
{
|
|
if (impl == null)
|
|
throw new SocketException("Not connected");
|
|
|
|
Object buf = impl.getOption(SocketOptions.SO_RCVBUF);
|
|
|
|
if (buf instanceof Integer)
|
|
return(((Integer)buf).intValue());
|
|
else
|
|
throw new SocketException("Internal Error: Unexpected type");
|
|
}
|
|
|
|
/**
|
|
* Closes the socket.
|
|
*
|
|
* @exception IOException If an error occurs
|
|
*/
|
|
public synchronized void close () throws IOException
|
|
{
|
|
if (impl != null)
|
|
impl.close();
|
|
}
|
|
|
|
/**
|
|
* Converts this <code>Socket</code> to a <code>String</code>.
|
|
*
|
|
* @return The <code>String</code> representation of this <code>Socket</code>
|
|
*/
|
|
public String toString ()
|
|
{
|
|
return("Socket " + impl);
|
|
}
|
|
|
|
// Class Methods
|
|
|
|
/**
|
|
* Sets the <code>SocketImplFactory</code>. This may be done only once per
|
|
* virtual machine. Subsequent attempts will generate a
|
|
* <code>SocketException</code>. Note that a <code>SecurityManager</code>
|
|
* check is made prior to setting the factory. If
|
|
* insufficient privileges exist to set the factory, then an
|
|
* <code>IOException</code> will be thrown.
|
|
*
|
|
* @exception SecurityException If the <code>SecurityManager</code> does
|
|
* not allow this operation.
|
|
* @exception SocketException If the SocketImplFactory is already defined
|
|
* @exception IOException If any other error occurs
|
|
*/
|
|
public static synchronized void setSocketImplFactory (SocketImplFactory fac)
|
|
throws IOException
|
|
{
|
|
// See if already set
|
|
if (factory != null)
|
|
throw new SocketException("SocketImplFactory already defined");
|
|
|
|
// Check permissions
|
|
SecurityManager sm = System.getSecurityManager();
|
|
if (sm != null)
|
|
sm.checkSetFactory();
|
|
|
|
factory = fac;
|
|
}
|
|
}
|