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/*******************************************************************************
*
* Struts2-Conversation-Plugin - An Open Source Conversation- and Flow-Scope Solution for Struts2-based Applications
* =================================================================================================================
*
* Copyright (C) 2012 by Rees Byars
* http://code.google.com/p/struts2-conversation/
*
* **********************************************************************************************************************
*
* 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.
*
* **********************************************************************************************************************
*
* $Id: ConversationAdapter.java reesbyars $
******************************************************************************/
package com.google.code.rees.scope.conversation;
import java.io.Serializable;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import com.google.code.rees.scope.conversation.configuration.ConversationClassConfiguration;
import com.google.code.rees.scope.conversation.configuration.DefaultConversationArbitrator;
import com.google.code.rees.scope.conversation.context.ConversationContext;
import com.google.code.rees.scope.conversation.processing.ConversationPostProcessor;
import com.google.code.rees.scope.conversation.processing.ConversationPostProcessorWrapper;
import com.google.code.rees.scope.conversation.processing.ConversationPostProcessorWrapperFactory;
import com.google.code.rees.scope.conversation.processing.DefaultConversationPostProcessorWrapperFactory;
/**
* This class is used to adapt/integrate the major components of the
* conversation management to control frameworks such as Struts2 and Spring MVC
* or any other framework.
*
* By employing the adapter pattern, the conversation management aspects are
* separated from the details of the control framework and separated even from
* the underlying request and session mechanisms.
*
* Makes use of {@link ThreadLocal} to make the current request's adapter
* available through the static call
* ConversationAdapter.getAdapter().
*
* @author rees.byars
*
*/
public abstract class ConversationAdapter implements Serializable {
private static final long serialVersionUID = -8006640931436858515L;
protected static ThreadLocal conversationAdapter = new ThreadLocal();
protected Map viewContext = new HashMap();
protected ConversationPostProcessorWrapperFactory postProcessorFactory = new DefaultConversationPostProcessorWrapperFactory();
protected Collection postProcessors = new HashSet();
public ConversationAdapter() {
conversationAdapter.set(this);
}
/**
* The controller instance, such as a Struts2 action class or a Spring MVC
* controller
*
* @return
*/
public abstract Object getAction();
/**
* A string identifying the current action. The convention employed by the
* {@link DefaultConversationArbitrator} is the name of the controller
* method being executed.
*
* @return
*/
public abstract String getActionId();
/**
* Returns a map containing, at a minimum, conversation name/id key/value
* pairs for the current request.
*
* @return
*/
public abstract Map getRequestContext();
/**
* begins a new conversation, returning the context for the new conversation
*
* @param conversationName
* @param maxIdleTimeMillis
* @return
*/
public abstract ConversationContext beginConversation(String conversationName, long maxIdleTimeMillis);
/**
* Returns a ConversationContext for the given name and ID
*
* @param conversationId
* @return
*/
public abstract ConversationContext getConversationContext(String conversationName, String conversationId);
/**
* Removes the conversation from the session, returning the context
*/
public abstract ConversationContext endConversation(String conversationName, String conversationId);
/**
* Returns a map that is used to place conversation name/id key/value pairs
* for placing in the view context (the view context being, for instance, a
* JSP).
*
* @return
*/
public Map getViewContext() {
return this.viewContext;
}
/**
* Add a {@link ConversationPostProcessor} that is guaranteed to be executed
* after action execution by a call to {@link #executePostProcessors()}
*
* @param postProcessor
* @param conversationConfig
* @param conversationId
*/
public void addPostProcessor(ConversationPostProcessor postProcessor, ConversationClassConfiguration conversationConfig, String conversationId) {
ConversationPostProcessorWrapper wrapper = this.postProcessorFactory.create(this, postProcessor, conversationConfig, conversationId);
this.postProcessors.add(wrapper);
}
/**
* Executes all {@link ConversationPostProcessor ConversationPostProcessors}
* that have been added using
* {@link #addPostProcessor(ConversationPostProcessor, ConversationClassConfiguration, String)}
*/
public void executePostProcessors() {
for (ConversationPostProcessorWrapper postProcessor : this.postProcessors) {
postProcessor.postProcessConversation();
}
}
/**
* Set the {@link ThreadLocal} ConversationAdapter for use with the current
* request. Called in the constructor to force new instances into the
* ThreadLocal.
*
* @param adapter
*/
public static void setAdapter(ConversationAdapter adapter) {
conversationAdapter.set(adapter);
}
/**
* Get the {@link ThreadLocal} ConversationAdapter associated with the
* current request
*
* @return
*/
public static ConversationAdapter getAdapter() {
return conversationAdapter.get();
}
/**
* clean up this resource once processing is completed for the request, static to guarantee that it references current thread's instance
*/
public static void cleanup() {
ConversationAdapter adapter = conversationAdapter.get();
conversationAdapter.remove();
if (adapter != null) {
adapter.doCleanup();
}
}
/**
* called by {@link #cleanup()}, can be overridden to tweak
*/
protected void doCleanup() {
}
}