EventDispatcher.java

/*
 * Copyright 2009 JBoss, a divison Red Hat, Inc
 *
 * Licensed 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.
 */
package org.jboss.errai.cdi.server;

import org.jboss.errai.bus.client.api.Message;
import org.jboss.errai.bus.client.api.MessageCallback;
import org.jboss.errai.bus.client.api.base.MessageBuilder;
import org.jboss.errai.bus.client.framework.MessageBus;
import org.jboss.errai.cdi.client.CDICommands;
import org.jboss.errai.cdi.client.CDIProtocol;
import org.jboss.errai.cdi.server.api.InboundQualifier;
import org.jboss.errai.cdi.server.api.Outbound;

import javax.enterprise.event.Observes;
import javax.enterprise.inject.spi.BeanManager;

/**
 * Acts as a bridge between Errai Bus and the CDI event system.<br/>
 * Includes marshalling/unmarshalling of event types.
 */
public class EventDispatcher implements MessageCallback
{
    private BeanManager beanManager;

    private MessageBus erraiBus;

    public final static String NAME = "cdi.event:Dispatcher";

    private ContextManager ctxMgr;

    public EventDispatcher(BeanManager beanManager, MessageBus erraiBus, ContextManager ctxMgr)
    {
        this.beanManager = beanManager;
        this.erraiBus = erraiBus;
        this.ctxMgr = ctxMgr;
    }

    // Invoked by Errai
    public void callback(Message message)
    {
        try
        {
            switch (CDICommands.valueOf(message.getCommandType()))
            {
                case CDI_EVENT:
                    String type = message.get(String.class, CDIProtocol.TYPE);
                    Class clazz = Thread.currentThread().getContextClassLoader().loadClass(type);
                    Object o = message.get(clazz, CDIProtocol.OBJECT_REF);
                    try {
                        ctxMgr.activateRequestContext();
                        beanManager.fireEvent(o, new InboundQualifier());
                    } finally {
                        ctxMgr.deactivateRequestContext();
                    }

                    break;
                default:
                    throw new IllegalArgumentException(
                            "Unknown command type "+message.getCommandType());
            }
        }
        catch (Exception e)
        {
            throw new RuntimeException("Failed to dispatch CDI Event", e);
        }
    }

    // Invoked by Weld Event producer
    public void sendMessage(@Observes Outbound event)
    {
        Object payload = event.getPayload();
        MessageBuilder.createMessage()
                .toSubject("cdi.event:"+payload.getClass().getName())
                .command(CDICommands.CDI_EVENT)
                .with(CDIProtocol.TYPE, payload.getClass().getName())
                .with(CDIProtocol.OBJECT_REF, event.getPayload())
                .noErrorHandling().sendNowWith(erraiBus);

    }
}