Conversation.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.client.api;

import org.jboss.errai.bus.client.ErraiBus;
import org.jboss.errai.bus.client.api.base.MessageBuilder;
import org.jboss.errai.ioc.client.api.GeneratedBy;

/**
 * Client side conversation handle.
 * Conversations and messages correlate through the subject.<br/>
 * Handles can be created through the
 * {@link org.jboss.errai.cdi.client.api.CDI#createConversation(String)} client interface.
 *
 * @see CDI
 *
 * @author: Heiko Braun <hbraun@redhat.com>
 * @date: Oct 5, 2010
 */
public class Conversation {

    private String id;
    private String subject;

    private boolean hasBegun, hasEnded = false;

    Conversation(String id, String subject) {
        this.id = id;
        this.subject = subject;
    }

    public String getSubject() {
        return subject;
    }

    public String getId() {
        return id;
    }

    public void begin()
    {
        assertBegun();
        
        // register client side conversation state globally
        // so that the message builder picks it
        // Once that's done we don't need to wrap the message builder calls

        CDI.getActiveConversations().put(id, this);
        hasBegun = true;
    }

    public boolean isActive()
    {
        return hasBegun;
    }

    /**
     * Explicitly end a conversation
     */
    public void end()
    {
        assertEnded();
        
        MessageBuilder.createMessage()
                .toSubject("cdi.conversation:Manager,conversation="+id)
                .command("end")                
                .with("cdi.conversation.id", id)
                .with("cdi.internal", true) // will be excluded in interceptor
                .done().sendNowWith(ErraiBus.get());

        CDI.getActiveConversations().remove(id);
        
        hasEnded = true;
    }

    public boolean hasEnded()
    {
        // might be a server side component ends the conversation
        // in that case this instance needs to be terminated to reflect the
        // server side state change
        return hasEnded;
    }

    private void assertEnded()
    {
        if(hasEnded)
            throw new IllegalStateException("Converation already ended: "+ id);
    }

    private void assertBegun()
    {
        if(hasBegun)
            throw new IllegalStateException("Converation already begun: "+ id);
    }

    public void reset() {        
        id = CDI.generateId();
        hasBegun= false;
        hasEnded = false;
    }
}