/* * Copyright (c) 2005, John Mettraux, OpenWFE.org * All rights reserved. *  * Redistribution and use in source and binary forms, with or without  * modification, are permitted provided that the following conditions are met: *  * . Redistributions of source code must retain the above copyright notice, this *   list of conditions and the following disclaimer.   *  * . Redistributions in binary form must reproduce the above copyright notice,  *   this list of conditions and the following disclaimer in the documentation  *   and/or other materials provided with the distribution. *  * . Neither the name of the "OpenWFE" nor the names of its contributors may be *   used to endorse or promote products derived from this software without *   specific prior written permission. *  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE  * POSSIBILITY OF SUCH DAMAGE. * * $Id$ *///// SubscriptionService.java//// john.mettraux@openwfe.org//// generated with // jtmpl 1.1.01 2004/05/19 (john.mettraux@openwfe.org)//package openwfe.org.sub;import java.lang.reflect.Method;import java.lang.reflect.InvocationTargetException;import openwfe.org.AbstractService;import openwfe.org.ApplicationContext;/** * This service will wait for registrations : other service subscribing for * topics by indicating their own service name and giving the Method they * want to be notified if anything is posted for the given topic. * This allows for an 'event system' or some multiplexing... * * <p><font size=2>CVS Info : * <br>$Author$ * <br>$Id$ </font> * * @author john.mettraux@openwfe.org */public class SubscriptionService    extends AbstractService{    /*     * this class was imagined in Schiphol gate F3 and written on      * KL 835 to Singapore, near Bob, an english bricklayer heading to     * Bali. I had seat 21H on a Boeing 747-400.     */    private final static org.apache.log4j.Logger log = org.apache.log4j.Logger        .getLogger(SubscriptionService.class.getName());    //    // CONSTANTS & co    /**     * This service should be stored in the application context     * as "subscriptionService" (that's the value that this constant     * is carrying).     */    public final static String S_SUBSCRIPTION_SERVICE        = "subscriptionService";    //    // FIELDS    private java.util.Map topicMap = new java.util.HashMap();    //    // CONSTRUCTORS    //    // METHODS    /**     * Any service may used to method to 'subscribe' to a given topic.     * The service has to give its serviceName in the applicationContext      * (this is how it will be reached) and the Method instance that as     * to be used for the notification.     */    public void subscribe         (final String topicName,          final String subscriberServiceName,          final Method method)    {        java.util.List subscribers = (java.util.List)this.topicMap            .get(topicName);        if (subscribers == null)        {            subscribers = new java.util.ArrayList(10);            this.topicMap.put(topicName, subscribers);        }        subscribers.add(new TopicMapEntry(subscriberServiceName, method));        log.debug            ("subscribe() topic:'"+topicName+"' method:'"+method.getName()+"'");    }    /**     * Emitting services use this method to 'multiplex' the event to     * the topic. The subscribed services will get notified by this      * SubscriptionService.     */    public void post        (final String topicName,         final Object[] arguments)    throws        Throwable    {        log.debug("post() topic:'"+topicName+"'");        java.util.List subscribers = (java.util.List)this.topicMap            .get(topicName);        if (subscribers == null) return;        final java.util.Iterator it = subscribers.iterator();        while (it.hasNext())        {            final TopicMapEntry entry = (TopicMapEntry)it.next();            final Object service = getContext()                .lookup(entry.subscriberServiceName);            try            {                entry.method.invoke(service, arguments);            }            catch (final IllegalArgumentException iae)            {                log.warn                    ("post() failure for topic:'"+topicName+                     "' subscriber:'"+entry.subscriberServiceName+"'",                      iae);            }            catch (final IllegalAccessException iae)            {                log.warn                    ("post() failure for topic:'"+topicName+                     "' subscriber:'"+entry.subscriberServiceName+"'",                      iae);            }            catch (final InvocationTargetException ite)            {                log.debug                    ("post() invocation exception for topic:'"+topicName+                     "' subscriber:'"+entry.subscriberServiceName+"'",                      ite.getCause());                throw ite.getCause();            }        }    }    //    // STATIC METHODS    /**     * Given an applicationContext, this static method will return      * the subscription service (if any) stored in it under the     * name given by S_SUBSCRIPTION_SERVICE.     */    public static SubscriptionService getSubcriptionService         (final ApplicationContext context)    {        return (SubscriptionService)context.lookup(S_SUBSCRIPTION_SERVICE);    }    //    // INNER CLASSES    /**     * Just a struct[ure] class.     */    protected static class TopicMapEntry    {        public String subscriberServiceName = null;        public Method method = null;        public TopicMapEntry             (final String subscriberServiceName, final Method method)        {            this.subscriberServiceName = subscriberServiceName;            this.method = method;        }    }}