/*
 * JBoss, Home of Professional Open Source
 * Copyright 2008, Red Hat Middleware LLC, and individual contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * 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 javax.enterprise.context;

/**
 * <p>Allows the application to manage the 
 * {@linkplain javax.enterprise.context.ConversationScoped conversation context}
 * by marking the current conversation as transient or long-running,
 * specifying a conversation identifier, or setting the conversation
 * timeout.</p>
 * 
 * <p>An instance may be injected:</p>
 * 
 * <pre>
 * &#064;Inject Conversation conversation;
 * </pre>
 * 
 * <p>The conversation timeout is a hint to the container 
 * that a conversation should not be destroyed if it has been 
 * active within the last given interval in milliseconds.</p>
 * 
 * @see javax.enterprise.context.ConversationScoped &#064;ConversationScoped
 * 
 * @author Pete Muir
 * @author Gavin King
 * 
 */
public interface Conversation
{

   /**
    * <p>Mark the current transient conversation long-running. A
    * conversation identifier is generated by the container.</p>
    * 
    * @throws IllegalStateException if the current conversation 
    * is already marked long-running.
    */
   public void begin();

   /**
    * <p>Mark the current transient conversation long-running,
    * with a specified identifier.</p>
    * 
    * @throws IllegalStateException if the current conversation 
    * is already marked long-running.
    * @throws IllegalArgumentException if a conversation with
    * the specified identifier already exists.
    */
   public void begin(String id);

   /**
    * <p>Marks the current long-running conversation transient.</p>
    * 
    * @throws IllegalStateException if the current conversation 
    * is already marked transient.
    */
   public void end();


   /**
    * <p>Get the identifier of the current long-running conversation.</p>
    * 
    * @return the identifier of the current long-running conversation, 
    * or a null value if the current conversation is transient.
    */
   public String getId();

   /**
    * <p>Get the timeout of the current conversation.</p>
    * 
    * @return the current timeout in milliseconds.
    */
   public long getTimeout();

   /**
    * <p>Set the timeout of the current conversation.</p>
    * 
    * @param milliseconds the new timeout in milliseconds.
    */
   public void setTimeout(long milliseconds);

   /**
    * <p>Determine if the conversation is marked transient or 
    * long-running.</p>
    * 
    * @return <tt>true</tt> if the conversation is marked transient, 
    * or <tt>false</tt>if it is marked long-running.
    */
   public boolean isTransient();
}