/* * * $Id: ChannelMessenger.java,v 1.4 2005/08/08 19:59:05 bondolo Exp $ * * Copyright (c) 2004 Sun Microsystems, Inc.  All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright *    notice, this list of conditions and the following disclaimer. * * 2. 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. * * 3. The end-user documentation included with the redistribution, *    if any, must include the following acknowledgment: *       "This product includes software developed by the *       Sun Microsystems, Inc. for Project JXTA." *    Alternately, this acknowledgment may appear in the software itself, *    if and wherever such third-party acknowledgments normally appear. * * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" *    must not be used to endorse or promote products derived from this *    software without prior written permission. For written *    permission, please contact Project JXTA at http://www.jxta.org. * * 5. Products derived from this software may not be called "JXTA", *    nor may "JXTA" appear in their name, without prior written *    permission of Sun. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 SUN MICROSYSTEMS OR * ITS 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. * * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of Project JXTA.  For more * information on Project JXTA, please see * <http://www.jxta.org/>. * * This license is based on the BSD license adopted by the Apache Foundation. */package net.jxta.endpoint;import net.jxta.peergroup.PeerGroupID;import org.apache.log4j.Level;import org.apache.log4j.Logger;/** * A Channel Messenger provides an exclusive interface to the shared messenger.  * * <p/>What is typically exclusive is the message queue, addressing parameters  * that are not usefully shared (serviceName, serviceParam), and if needed  * cross-group address rewritting parameters. * * <p/>This class is provided as a base for implementing such channel messengers,  * which are typically what Messenger.getChannelMessenger() needs to return.  * * @see net.jxta.endpoint.EndpointService * @see net.jxta.endpoint.EndpointAddress * @see net.jxta.endpoint.Message **/public abstract class ChannelMessenger extends AbstractMessenger implements Messenger {    /**     * insertedServicePrefix This is how all valid inserted services start. This      * lets us recognize if a message already has an inserted service. Then we      * must not add another one. Only the top-most one counts.  Since insertion      * is only done here, the constant is defined here. Even if historically it      * was done within the endpoint implementation, it has become a protocol now.     **/    public static final String InsertedServicePrefix = "EndpointService:";    private String insertedService;    /**     * The worker that implements sendMessage-with-listener for this channel. If     * there's none, sendMessage-with-listener will throw an exception. Channels      * returned by getMessenger methods all have one already. It is up to the      * invoker of getChannelMessenger to supply one or not.     **/    private ListenerAdaptor messageWatcher;    protected String origService;        protected String origServiceParam;        /**     * Figure out what the service string will be after mangling (if required)      * and applying relevant defaults.     *     * @param service The service name in the unmangled address.     * @return String The service name in the mangled address.     **/    protected String effectiveService( String service ) {        // No redirection required. Just apply the default service.        if (insertedService == null) {            return (service == null) ? origService : service;        }        // Check if redirection is applicable.        return ((service != null) && service.startsWith(InsertedServicePrefix)) ? service : insertedService;    }    /**     * Figure out what the param string will be after mangling (if required) and      * applying relevant defaults.     *     * @param service The service name in the unmangled address.     * @param serviceParam The service parameter in the unmangled address.     * @return String The service parameter in the mangled address.     **/    protected String effectiveParam( String service, String serviceParam ) {        // No redirection required. Or not applicable. Just apply the default param.        if ((insertedService == null) || ((service != null) && service.startsWith(InsertedServicePrefix))) {            return (serviceParam == null) ? origServiceParam : serviceParam;        }        // Apply redirection. We need the effective service, now.        if (service == null) {            service = origService;        }        if (serviceParam == null) {            serviceParam = origServiceParam;        }        return ((null != service) && (null != serviceParam)) ? (service + "/" + serviceParam) : service;    }    /**     * Give this channel the watcher that it must use whenever sendMessage(...,listener) is used. If not set,     * sendMessage(..., listener) will throw.     * @deprecated This method is in support of deprecated methods.     **/    public void setMessageWatcher( ListenerAdaptor messageWatcher ) {        this.messageWatcher = messageWatcher;    }    /**     * Create a new ChannelMessenger     *      * @param baseAddress The network address messages go to; regardless of service, param, or group.     * @param groupRedirection Group to which the messages must be redirected. This is used to implement the automatic group     * seggregation which has become a de-facto standard. If not null, the unique portion of the specified groupID is     * prepended with {@link #InsertedServicePrefix} and inserted in every message's destination address in place of the     * the original service name, which gets shifted into the begining of the service parameter. The opposite is done     * on arrival to restore the original destination address before the message is delivered to the listener in the     * the specified group. Messages that already bear a group redirection are not affected.     * @param origService The default destination service for messages sent without specifying a different service.     * @param origServiceParam The default destination service parameter for messages sent without specifying a different service     * parameter.     **/    public ChannelMessenger( EndpointAddress baseAddress, PeerGroupID groupRedirection,                             String origService, String origServiceParam ) {        // FIXME: The inserted service business is really messy. Group seggregation does not have to be the endpoint service's        // business. It should be specified by the app as part of the destination address. What we're doing here        // is simply enforcing what could just be a convention.        super(baseAddress);        if (groupRedirection == null) {            insertedService = null;        } else {            insertedService = InsertedServicePrefix + groupRedirection.getUniqueValue().toString();        }        this.origService = origService;        this.origServiceParam = origServiceParam;        // Now that we're initialized enough, grab the destination addr from our superclass and fix it.  We add the service and        // param; NOT the group mangling: getDestinationAddress[Object]() should always return what was given at construction.        EndpointAddress dest = getDestinationAddressObject();        dest.setServiceName(origService);        dest.setServiceParameter(origServiceParam);    }        /**     * {@inheritDoc}     *     * <p/> By default a channel refuses to make a channel.     *     **/    public Messenger getChannelMessenger( PeerGroupID redirection, String service, String serviceParam ) {        return null;    }        /**     * {@inheritDoc}     *     * @deprecated Implements deprecated method.     **/    public void sendMessage(Message msg, String service, String serviceParam, OutgoingMessageEventListener listener) {        if (messageWatcher == null) {            throw new UnsupportedOperationException("This channel was not configured to emulate this legacy method.");        }        // Cleanup the message from any existing result prop since we're going to use select.        msg.setMessageProperty(Messenger.class, null);        // Tell the watcher to select that message.        messageWatcher.watchMessage(listener, msg);        sendMessageN(msg, service, serviceParam);    }}