/projects/ApacheHttpClient/src/java/org/apache/commons/httpclient/protocol/ControllerThreadSocketFactory.java

/*

 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/protocol/ControllerThreadSocketFactory.java,v 1.2 2004/04/18 23:51:38 jsdever Exp $

 * $Revision: 480424 $

 * $Date: 2006-11-29 11:26:49 +0530 (Wed, 29 Nov 2006) $

 *

 * ====================================================================

 *

 *  Licensed to the Apache Software Foundation (ASF) under one or more

 *  contributor license agreements.  See the NOTICE file distributed with

 *  this work for additional information regarding copyright ownership.

 *  The ASF licenses this file to You under the Apache License, Version 2.0

 *  (the "License"); you may not use this file except in compliance with

 *  the License.  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 *  Unless required by applicable law or agreed to in writing, software

 *  distributed under the License is distributed on an "AS IS" BASIS,

 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 *  See the License for the specific language governing permissions and

 *  limitations under the License.

 * ====================================================================

 *

 * This software consists of voluntary contributions made by many

 * individuals on behalf of the Apache Software Foundation.  For more

 * information on the Apache Software Foundation, please see

 * <http://www.apache.org/>.

 *

 */



package org.apache.commons.httpclient.protocol;



import java.io.IOException;

import java.net.InetAddress;

import java.net.Socket;

import java.net.UnknownHostException;



import org.apache.commons.httpclient.ConnectTimeoutException;

import org.apache.commons.httpclient.util.TimeoutController;



/**

 * This helper class is intedned to help work around the limitation of older Java versions

 * (older than 1.4) that prevents from specifying a connection timeout when creating a

 * socket. This factory executes a controller thread overssing the process of socket 

 * initialisation. If the socket constructor cannot be created within the specified time

 * limit, the controller terminates and throws an {@link ConnectTimeoutException} 

 * 

 * @author Ortwin Glueck

 * @author Oleg Kalnichevski

 * 

 * @since 3.0

 */

public final class ControllerThreadSocketFactory {



    private ControllerThreadSocketFactory() {

        super();

    }



    /**

     * This method spawns a controller thread overseeing the process of socket 

     * initialisation. If the socket constructor cannot be created within the specified time

     * limit, the controller terminates and throws an {@link ConnectTimeoutException}

     * 

     * @param host the host name/IP

     * @param port the port on the host

     * @param localAddress the local host name/IP to bind the socket to

     * @param localPort the port on the local machine

     * @param timeout the timeout value to be used in milliseconds. If the socket cannot be

     *        completed within the given time limit, it will be abandoned

     * 

     * @return a connected Socket

     * 

     * @throws IOException if an I/O error occurs while creating the socket

     * @throws UnknownHostException if the IP address of the host cannot be

     * determined

     * @throws ConnectTimeoutException if socket cannot be connected within the

     *  given time limit

     * 

     */

    public static Socket createSocket(

        final ProtocolSocketFactory socketfactory, 

        final String host,

        final int port,

        final InetAddress localAddress,

        final int localPort,

        int timeout)

     throws IOException, UnknownHostException, ConnectTimeoutException

    {

            SocketTask task = new SocketTask() {

                public void doit() throws IOException {

                    setSocket(socketfactory.createSocket(host, port, localAddress, localPort));

                }                 

            };

            try {

                TimeoutController.execute(task, timeout);

            } catch (TimeoutController.TimeoutException e) {

                throw new ConnectTimeoutException(

                    "The host did not accept the connection within timeout of " 

                    + timeout + " ms");

            }

            Socket socket = task.getSocket();

            if (task.exception != null) {

                throw task.exception;

            }

            return socket;

    }



    public static Socket createSocket(final SocketTask task, int timeout)

     throws IOException, UnknownHostException, ConnectTimeoutException

    {

            try {

                TimeoutController.execute(task, timeout);

            } catch (TimeoutController.TimeoutException e) {

                throw new ConnectTimeoutException(

                    "The host did not accept the connection within timeout of " 

                    + timeout + " ms");

            }

            Socket socket = task.getSocket();

            if (task.exception != null) {

                throw task.exception;

            }

            return socket;

    }



    /**

    * Helper class for wrapping socket based tasks.

    */

    public static abstract class SocketTask implements Runnable {

        /** The socket */

        private Socket socket;

        /** The exception */

        private IOException exception;



        /**

         * Set the socket.

         * @param newSocket The new socket.

         */

        protected void setSocket(final Socket newSocket) {

            socket = newSocket;

        }



        /**

         * Return the socket.

         * @return Socket The socket.

         */

        protected Socket getSocket() {

            return socket;

        }

        /**

         * Perform the logic.

         * @throws IOException If an IO problem occurs

         */

        public abstract void doit() throws IOException;



        /** Execute the logic in this object and keep track of any exceptions. */

        public void run() {

            try {

                doit();

            } catch (IOException e) {

                exception = e;

            }

        }

    }

}