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Java example source code file (MultihomePlainSocketFactory.java)

This example source code file (MultihomePlainSocketFactory.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java tags/keywords

connecttimeoutexception, default_factory, httpparams, illegalargumentexception, inetaddress, inetsocketaddress, io, ioexception, list, multihomeplainsocketfactory, net, network, parameters, socket, sockettimeoutexception, string, target, util

The MultihomePlainSocketFactory.java example source code

/*
 * ====================================================================
 * 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.http.conn;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketTimeoutException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Arrays;

import org.apache.http.annotation.Immutable;

import org.apache.http.conn.scheme.SocketFactory;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;

/**
 * Socket factory that implements a simple multi-home fail-over on connect failure, 
 * provided the same hostname resolves to multiple {@link InetAddress}es. Please note
 * the {@link #connectSocket(Socket, String, int, InetAddress, int, HttpParams)}
 * method cannot be reliably interrupted by closing the socket returned by the
 * {@link #createSocket()} method.
 *
 * @since 4.0
 */
@Immutable
public final class MultihomePlainSocketFactory implements SocketFactory {

    /**
     * The factory singleton.
     */
    private static final
    MultihomePlainSocketFactory DEFAULT_FACTORY = new MultihomePlainSocketFactory();

    /**
     * Gets the singleton instance of this class.
     * @return the one and only plain socket factory
     */
    public static MultihomePlainSocketFactory getSocketFactory() {
        return DEFAULT_FACTORY;
    }

    /**
     * Restricted default constructor.
     */
    private MultihomePlainSocketFactory() {
        super();
    }


    // non-javadoc, see interface org.apache.http.conn.SocketFactory
    public Socket createSocket() {
        return new Socket();
    }

    /**
     * Attempts to connects the socket to any of the {@link InetAddress}es the 
     * given host name resolves to. If connection to all addresses fail, the  
     * last I/O exception is propagated to the caller.
     * 
     * @param sock socket to connect to any of the given addresses
     * @param host Host name to connect to
     * @param port the port to connect to
     * @param localAddress local address
     * @param localPort local port
     * @param params HTTP parameters 
     * 
     * @throws  IOException if an error occurs during the connection
     * @throws  SocketTimeoutException if timeout expires before connecting
     */
    public Socket connectSocket(Socket sock, String host, int port, 
                                InetAddress localAddress, int localPort,
                                HttpParams params)
        throws IOException {

        if (host == null) {
            throw new IllegalArgumentException("Target host may not be null.");
        }
        if (params == null) {
            throw new IllegalArgumentException("Parameters may not be null.");
        }

        if (sock == null)
            sock = createSocket();

        if ((localAddress != null) || (localPort > 0)) {

            // we need to bind explicitly
            if (localPort < 0)
                localPort = 0; // indicates "any"

            InetSocketAddress isa =
                new InetSocketAddress(localAddress, localPort);
            sock.bind(isa);
        }

        int timeout = HttpConnectionParams.getConnectionTimeout(params);

        InetAddress[] inetadrs = InetAddress.getAllByName(host);
        List<InetAddress> addresses = new ArrayList(inetadrs.length);
        addresses.addAll(Arrays.asList(inetadrs));
        Collections.shuffle(addresses);

        IOException lastEx = null;
        for (InetAddress remoteAddress: addresses) {
            try {
                sock.connect(new InetSocketAddress(remoteAddress, port), timeout);
                break;
            } catch (SocketTimeoutException ex) {
                throw new ConnectTimeoutException("Connect to " + remoteAddress + " timed out");
            } catch (IOException ex) {
                // create new socket
                sock = new Socket();
                // keep the last exception and retry
                lastEx = ex;
            }
        }
        if (lastEx != null) {
            throw lastEx;
        }
        return sock;
    } // connectSocket


    /**
     * Checks whether a socket connection is secure.
     * This factory creates plain socket connections
     * which are not considered secure.
     *
     * @param sock      the connected socket
     *
     * @return  <code>false
     *
     * @throws IllegalArgumentException if the argument is invalid
     */
    public final boolean isSecure(Socket sock)
        throws IllegalArgumentException {

        if (sock == null) {
            throw new IllegalArgumentException("Socket may not be null.");
        }
        // This class check assumes that createSocket() calls the constructor
        // directly. If it was using javax.net.SocketFactory, we couldn't make
        // an assumption about the socket class here.
        if (sock.getClass() != Socket.class) {
            throw new IllegalArgumentException
                ("Socket not created by this factory.");
        }
        // This check is performed last since it calls a method implemented
        // by the argument object. getClass() is final in java.lang.Object.
        if (sock.isClosed()) {
            throw new IllegalArgumentException("Socket is closed.");
        }

        return false;

    } // isSecure

}

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