Initial revision

From-SVN: r102074

libjava/classpath/java/net/SocketImpl.java

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+/* SocketImpl.java -- Abstract socket implementation class
+   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
+   Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package java.net;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+
+/* Written using on-line Java Platform 1.2 API Specification.
+ * Believed complete and correct.
+ */
+
+/**
+ * This abstract class serves as the parent class for socket implementations.
+ * The implementation class serves an intermediary to native routines that
+ * perform system specific socket operations.
+ * <p>
+ * A default implementation is provided by the system, but this can be
+ * changed via installing a <code>SocketImplFactory</code> (through a call
+ * to the static method <code>Socket.setSocketImplFactory</code>).  A
+ * subclass of <code>Socket</code> can also pass in a <code>SocketImpl</code>
+ * to the <code>Socket(SocketImpl)</code> constructor to use an
+ * implementation different from the system default without installing
+ * a factory.
+ *
+ * @author Aaron M. Renn (arenn@urbanophile.com)
+ * @author Per Bothner (bothner@cygnus.com)
+ */
+public abstract class SocketImpl implements SocketOptions
+{
+  /**
+   * The address of the remote end of the socket connection
+   */
+  protected InetAddress address;
+
+  /**
+   * A FileDescriptor object representing this socket connection.
+   */
+  protected FileDescriptor fd;
+
+  /**
+   * The port number the socket is bound to locally
+   */
+  protected int localport = -1;
+
+  /**
+   * The port number of the remote end of the socket connection
+   */
+  protected int port;
+
+  /**
+   * Default, no-argument constructor for use by subclasses.
+   */
+  public SocketImpl()
+  {
+  }
+
+  /**
+   * Creates a new socket that is not bound to any local address/port and
+   * is not connected to any remote address/port.  This will be created as
+   * a stream socket if the stream parameter is true, or a datagram socket
+   * if the stream parameter is false.
+   *
+   * @param stream true for a stream socket, false for a datagram socket
+   *
+   * @exception IOException If an error occurs
+   */
+  protected abstract void create(boolean stream) throws IOException;
+
+  /**
+   * Connects to the remote hostname and port specified as arguments.
+   *
+   * @param host The remote hostname to connect to
+   * @param port The remote port to connect to
+   *
+   * @exception IOException If an error occurs
+   */
+  protected abstract void connect(String host, int port)
+    throws IOException;
+
+  /**
+   * Connects to the remote address and port specified as arguments.
+   *
+   * @param host The remote address to connect to
+   * @param port The remote port to connect to
+   *
+   * @exception IOException If an error occurs
+   */
+  protected abstract void connect(InetAddress host, int port)
+    throws IOException;
+
+  /**
+   * Connects to the socket to the host specified in address. This
+   * method blocks until successful connected or the timeout occurs.
+   * A timeout of zero means no timout.
+   *
+   * @param address Data of remote host
+   * @param timeout time to wait to stop connecting
+   *
+   * @exception IOException If an error occurs
+   *
+   * @since 1.4
+   */
+  protected abstract void connect(SocketAddress address, int timeout)
+    throws IOException;
+
+  /**
+   * Binds to the specified port on the specified addr.  Note that this addr
+   * must represent a local IP address.
+   * <p>
+   * Note that it is unspecified how to bind to all interfaces on the localhost
+   * (INADDR_ANY).
+   *
+   * @param host The address to bind to
+   * @param port The port number to bind to
+   *
+   * @exception IOException If an error occurs
+   */
+  protected abstract void bind(InetAddress host, int port)
+    throws IOException;
+
+  /**
+   * Starts listening for connections on a socket. The backlog parameter
+   * is how many pending connections will queue up waiting to be serviced
+   * before being accept'ed.  If the queue of pending requests exceeds this
+   * number, additional connections will be refused.
+   *
+   * @param backlog The length of the pending connection queue
+   *
+   * @exception IOException If an error occurs
+   */
+  protected abstract void listen(int backlog) throws IOException;
+
+  /**
+   * Accepts a connection on this socket.
+   *
+   * @param s The implementation object for the accepted connection.
+   *
+   * @exception IOException If an error occurs
+   */
+  protected abstract void accept(SocketImpl s) throws IOException;
+
+  /**
+   * Returns an <code>InputStream</code> object for reading from this socket.
+   *
+   * @return An <code>InputStream</code> for reading from this socket.
+   *
+   * @exception IOException If an error occurs
+   */
+  protected abstract InputStream getInputStream() throws IOException;
+
+  /**
+   * Returns an <code>OutputStream</code> object for writing to this socket
+   *
+   * @return An <code>OutputStream</code> for writing to this socket.
+   *
+   * @exception IOException If an error occurs.
+   */
+  protected abstract OutputStream getOutputStream() throws IOException;
+
+  /**
+   * Returns the number of bytes that the caller can read from this socket
+   * without blocking.
+   *
+   * @return The number of readable bytes before blocking
+   *
+   * @exception IOException If an error occurs
+   */
+  protected abstract int available() throws IOException;
+
+  /**
+   * Closes the socket.  This will normally cause any resources, such as the
+   * InputStream, OutputStream and associated file descriptors  to be freed.
+   * <p>
+   * Note that if the SO_LINGER option is set on this socket, then the
+   * operation could block.
+   *
+   * @exception IOException If an error occurs
+   */
+  protected abstract void close() throws IOException;
+
+  /**
+   * Returns the FileDescriptor objects for this socket.
+   *
+   * @return A FileDescriptor for this socket.
+   */
+  protected FileDescriptor getFileDescriptor()
+  {
+    return fd;
+  }
+
+  /**
+   * Returns the remote address this socket is connected to
+   *
+   * @return The remote address
+   */
+  protected InetAddress getInetAddress()
+  {
+    return address;
+  }
+
+  /**
+   * Returns the remote port this socket is connected to
+   *
+   * @return The remote port
+   */
+  protected int getPort()
+  {
+    return port;
+  }
+
+  /**
+   * Returns true or false when this socket supports sending urgent data
+   * or not.
+   *
+   * @return true if the socket implementation supports sending urgent data,
+   * false otherwise
+   *
+   * @since 1.4
+   */
+  protected boolean supportsUrgentData()
+  {
+    // This method has to be overwritten by socket classes that support
+    // sending urgend data.
+    return false;
+  }
+
+  /**
+   * Sends one byte of urgent data to the socket.
+   *
+   * @param data The byte to send, the low eight bits of it
+   *
+   * @exception IOException If an error occurs
+   *
+   * @since 1.4
+   */
+  protected abstract void sendUrgentData(int data) throws IOException;
+
+  /**
+   * Returns the local port this socket is bound to
+   *
+   * @return The local port
+   */
+  protected int getLocalPort()
+  {
+    return localport;
+  }
+
+  /**
+   * Returns a <code>String</code> representing the remote host and port of
+   * this socket.
+   *
+   * @return A <code>String</code> for this socket.
+   */
+  public String toString()
+  {
+    return "[addr="
+           + ((address == null) ? "0.0.0.0/0.0.0.0" : address.toString())
+           + ",port=" + port + ",localport=" + localport + "]";
+  }
+
+  /**
+   * Shut down the input side of this socket.  Subsequent reads will
+   * return end-of-file.
+   *
+   * @exception IOException if an error occurs
+   */
+  protected void shutdownInput() throws IOException
+  {
+    throw new IOException("Not implemented in this socket class");
+  }
+
+  /**
+   * Shut down the output side of this socket.  Subsequent writes will
+   * fail with an IOException.
+   *
+   * @exception IOException if an error occurs
+   */
+  protected void shutdownOutput() throws IOException
+  {
+    throw new IOException("Not implemented in this socket class");
+  }
+}