001    /** 
002     * 
003     * Copyright 2004 Protique Ltd
004     * 
005     * Licensed under the Apache License, Version 2.0 (the "License"); 
006     * you may not use this file except in compliance with the License. 
007     * You may obtain a copy of the License at 
008     * 
009     * http://www.apache.org/licenses/LICENSE-2.0
010     * 
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS, 
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
014     * See the License for the specific language governing permissions and 
015     * limitations under the License. 
016     * 
017     **/
018    
019    package org.activemq.transport.reliable;
020    
021    import org.activemq.io.WireFormat;
022    import org.activemq.transport.TransportChannel;
023    import org.activemq.transport.composite.CompositeTransportChannelFactory;
024    import org.activemq.util.JMSExceptionHelper;
025    
026    import javax.jms.JMSException;
027    import java.net.URI;
028    import java.net.URISyntaxException;
029    import java.util.ArrayList;
030    import java.util.Arrays;
031    import java.util.List;
032    
033    /**
034     * A Reliable implementation of a TransportChannelFactory
035     *
036     * @version $Revision: 1.1.1.1 $
037     */
038    public class ReliableTransportChannelFactory extends CompositeTransportChannelFactory {
039        
040        /**
041         * Create a TransportChannel
042         *
043         * @param wireFormat     - the on-the-wire marshaller
044         * @param remoteLocation - location to bind to
045         * @return a reliable transport channel
046         * @throws JMSException if an error occurs
047         */
048        public TransportChannel create(WireFormat wireFormat, URI remoteLocation) throws JMSException {
049            try {
050                List uris = new ArrayList();
051                String text = parseURIs(uris, remoteLocation);
052                uris = randomizeURIs(uris);
053    
054                    ReliableTransportChannel channel = new ReliableTransportChannel(wireFormat, uris);
055                channel = (ReliableTransportChannel) populateProperties(channel, text);
056                
057                // Using singleton pattern since this factory isn't a singleton itself
058                KeepAliveDaemon daemon = KeepAliveDaemon.getInstance();
059                daemon.addMonitoredChannel(channel);
060                daemon.start();
061                
062                return channel;
063            }
064            catch (URISyntaxException e) {
065                throw JMSExceptionHelper.newJMSException("Can't parse list of URIs for: " + remoteLocation + ". Reason: "
066                        + e, e);
067            }
068        }
069    
070        /**
071         * @param uris - the URIs to randomize
072         * @return randomized array
073         */
074        protected List randomizeURIs(List uris) {
075            if (!uris.isEmpty()) {
076                int size = uris.size();
077                Object[] result = new Object[size];
078                SMLCGRandom random = new SMLCGRandom();
079                int startIndex = (int) (random.nextDouble() * (size + 1));
080                int count = 0;
081                for (int i = startIndex; i < size; i++) {
082                    result[count++] = uris.get(i);
083                }
084                for (int i = 0; i < startIndex; i++) {
085                    result[count++] = uris.get(i);
086                }
087                return new ArrayList(Arrays.asList(result));
088            }
089            return uris;
090        }
091    }