java.net

Class SocketImpl

Implemented Interfaces:
SocketOptions
Known Direct Subclasses:
PlainSocketImpl

public abstract class SocketImpl
extends Object
implements SocketOptions

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.

A default implementation is provided by the system, but this can be changed via installing a SocketImplFactory (through a call to the static method Socket.setSocketImplFactory). A subclass of Socket can also pass in a SocketImpl to the Socket(SocketImpl) constructor to use an implementation different from the system default without installing a factory.

Field Summary

protected InetAddress
address
The address of the remote end of the socket connection
protected FileDescriptor
fd
A FileDescriptor object representing this socket connection.
protected int
localport
The port number the socket is bound to locally
protected int
port
The port number of the remote end of the socket connection

Fields inherited from interface java.net.SocketOptions

IP_MULTICAST_IF, IP_MULTICAST_IF2, IP_MULTICAST_LOOP, IP_TOS, SO_BINDADDR, SO_BROADCAST, SO_KEEPALIVE, SO_LINGER, SO_OOBINLINE, SO_RCVBUF, SO_REUSEADDR, SO_SNDBUF, SO_TIMEOUT, TCP_NODELAY

Constructor Summary

SocketImpl()
Default, no-argument constructor for use by subclasses.

Method Summary

protected abstract void
accept(SocketImpl s)
Accepts a connection on this socket.
protected abstract int
available()
Returns the number of bytes that the caller can read from this socket without blocking.
protected abstract void
bind(InetAddress host, int port)
Binds to the specified port on the specified addr.
protected abstract void
close()
Closes the socket.
protected abstract void
connect(String host, int port)
Connects to the remote hostname and port specified as arguments.
protected abstract void
connect(InetAddress host, int port)
Connects to the remote address and port specified as arguments.
protected abstract void
connect(SocketAddress address, int timeout)
Connects to the socket to the host specified in address.
protected abstract void
create(boolean stream)
Creates a new socket that is not bound to any local address/port and is not connected to any remote address/port.
protected FileDescriptor
getFileDescriptor()
Returns the FileDescriptor objects for this socket.
protected InetAddress
getInetAddress()
Returns the remote address this socket is connected to
protected abstract InputStream
getInputStream()
Returns an InputStream object for reading from this socket.
protected int
getLocalPort()
Returns the local port this socket is bound to
protected abstract OutputStream
getOutputStream()
Returns an OutputStream object for writing to this socket
protected int
getPort()
Returns the remote port this socket is connected to
protected abstract void
listen(int backlog)
Starts listening for connections on a socket.
protected abstract void
sendUrgentData(int data)
Sends one byte of urgent data to the socket.
protected void
shutdownInput()
Shut down the input side of this socket.
protected void
shutdownOutput()
Shut down the output side of this socket.
protected boolean
supportsUrgentData()
Returns true or false when this socket supports sending urgent data or not.
String
toString()
Returns a String representing the remote host and port of this socket.

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

address

protected InetAddress address
The address of the remote end of the socket connection

fd

protected FileDescriptor fd
A FileDescriptor object representing this socket connection.

localport

protected int localport
The port number the socket is bound to locally

port

protected int port
The port number of the remote end of the socket connection

Constructor Details

SocketImpl

public SocketImpl()
Default, no-argument constructor for use by subclasses.

Method Details

accept

protected abstract void accept(SocketImpl s)
            throws IOException
Accepts a connection on this socket.
Parameters:
s - The implementation object for the accepted connection.
Throws:
IOException - If an error occurs

available

protected abstract int available()
            throws IOException
Returns the number of bytes that the caller can read from this socket without blocking.
Returns:
The number of readable bytes before blocking
Throws:
IOException - If an error occurs

bind

protected abstract void bind(InetAddress host,
                             int port)
            throws IOException
Binds to the specified port on the specified addr. Note that this addr must represent a local IP address.

Note that it is unspecified how to bind to all interfaces on the localhost (INADDR_ANY).

Parameters:
host - The address to bind to
port - The port number to bind to
Throws:
IOException - If an error occurs

close

protected abstract void close()
            throws IOException
Closes the socket. This will normally cause any resources, such as the InputStream, OutputStream and associated file descriptors to be freed.

Note that if the SO_LINGER option is set on this socket, then the operation could block.

Throws:
IOException - If an error occurs

connect

protected abstract void connect(String host,
                                int port)
            throws IOException
Connects to the remote hostname and port specified as arguments.
Parameters:
host - The remote hostname to connect to
port - The remote port to connect to
Throws:
IOException - If an error occurs

connect

protected abstract void connect(InetAddress host,
                                int port)
            throws IOException
Connects to the remote address and port specified as arguments.
Parameters:
host - The remote address to connect to
port - The remote port to connect to
Throws:
IOException - If an error occurs

connect

protected abstract void connect(SocketAddress address,
                                int timeout)
            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.
Parameters:
address - Data of remote host
timeout - time to wait to stop connecting
Throws:
IOException - If an error occurs
Since:
1.4

create

protected abstract void create(boolean stream)
            throws IOException
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.
Parameters:
stream - true for a stream socket, false for a datagram socket
Throws:
IOException - If an error occurs

getFileDescriptor

protected FileDescriptor getFileDescriptor()
Returns the FileDescriptor objects for this socket.
Returns:
A FileDescriptor for this socket.

getInetAddress

protected InetAddress getInetAddress()
Returns the remote address this socket is connected to
Returns:
The remote address

getInputStream

protected abstract InputStream getInputStream()
            throws IOException
Returns an InputStream object for reading from this socket.
Returns:
An InputStream for reading from this socket.
Throws:
IOException - If an error occurs

getLocalPort

protected int getLocalPort()
Returns the local port this socket is bound to
Returns:
The local port

getOutputStream

protected abstract OutputStream getOutputStream()
            throws IOException
Returns an OutputStream object for writing to this socket
Returns:
An OutputStream for writing to this socket.
Throws:
IOException - If an error occurs.

getPort

protected int getPort()
Returns the remote port this socket is connected to
Returns:
The remote port

listen

protected abstract void listen(int backlog)
            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.
Parameters:
backlog - The length of the pending connection queue
Throws:
IOException - If an error occurs

sendUrgentData

protected abstract void sendUrgentData(int data)
            throws IOException
Sends one byte of urgent data to the socket.
Parameters:
data - The byte to send, the low eight bits of it
Throws:
IOException - If an error occurs
Since:
1.4

shutdownInput

protected void shutdownInput()
            throws IOException
Shut down the input side of this socket. Subsequent reads will return end-of-file.
Throws:
IOException - if an error occurs

shutdownOutput

protected void shutdownOutput()
            throws IOException
Shut down the output side of this socket. Subsequent writes will fail with an IOException.
Throws:
IOException - if an error occurs

supportsUrgentData

protected boolean supportsUrgentData()
Returns true or false when this socket supports sending urgent data or not.
Returns:
true if the socket implementation supports sending urgent data, false otherwise
Since:
1.4

toString

public String toString()
Returns a String representing the remote host and port of this socket.
Overrides:
toString in interface Object
Returns:
A String for this socket.

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.