Brainstorm/Foundation/src/com/foundation/attribute/ReflectionCreationAgent.java

/*
 * Copyright (c) 2006,2009 Declarative Engineering LLC.
 * All rights reserved.  This program and the accompanying materials
 * are made available under the terms of the Declarative Engineering LLC
 * verson 1 which accompanies this distribution, and is available at
 * http://declarativeengineering.com/legal/DE_Developer_License_v1.txt
 */
package com.foundation.attribute;

import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;

import com.common.orb.Orb;
import com.common.thread.IRunnable;
import com.common.util.IIterator;
import com.common.util.IList;
import com.common.util.LiteHashMap;
import com.common.util.LiteList;

/*
 * An agent which will be sent to a remote process to create one or more reflections (actually returns reflection data objects which must be reconstituted into reflections).
 * The result of the agent is an IList of ReflectDataContainers where the last container has the last used reflection identifier that is valid.
 * The first result in each of the containers is the reflection that was asked for.
 * <p>
 * Warning: This agent is not a good way to get reflections.  It is better to use metadata and load all the collection's reflections at the time the collection is reflected.
 * This is possible because all reflection contexts are single threaded meaning that they can start reflecting data and the process can use as many id's as necessary since
 * another thread cannot start loading other reflections at the same time from the same context.  This agent is made to be functional, but may be inefficient.
 * </p>
 */
public class ReflectionCreationAgent implements IRunnable, java.io.Externalizable {
	/** The collection of references to reflectable objects requiring reflection. */
	private IList reflectables = null;
	/** The update handler that the reflected objects will notify when the reflection requires updating. */
	private IReflectUpdateHandler updateHandler = null;
	/** The optional class which defines metadata used for determining what is reflected.  The defining class' metadata will be indexed in the metadata service by the class object. */
	private Class metadataIndex = null;
	
	/**
	 * ReflectionCreationAgent default constructor.
	 */
	public ReflectionCreationAgent() {
	}//ReflectionCreationAgent()//
	/**
	 * ReflectionCreationAgent constructor.
	 * @param reflectables The collection of reflectable proxies which either exist on the target process or exist furthor down the virtual network connection.
	 * @param updateHandler The update handler that will handle updates from the created reflections.
	 */
	public ReflectionCreationAgent(IList reflectables, IReflectUpdateHandler updateHandler, Class metadataIndex) {
		this.reflectables = reflectables;
		this.updateHandler = Orb.isLocal(updateHandler) ? (IReflectUpdateHandler) Orb.getProxy(updateHandler, IReflectUpdateHandler.class) : updateHandler;
	}//ReflectionCreationAgent()//
	/* (non-Javadoc)
	 * @see com.common.thread.IRunnable#run()
	 */
	public Object run() {
		IList result = new LiteList(reflectables.getSize());
		LiteHashMap binnedReflectables = new LiteHashMap(10);

		//Organize the reflectable references into lists indexed by the process (identified by the connectionIdentifier) they exist on, where null is the local process.//
		for(int index = 0; index < reflectables.getSize(); index++) {
			IReflectable value = (IReflectable) reflectables.get(index);
			Object connectionIdentifier = Orb.getConnectionIdentifier(value);
			IList reflectables = null;
			
			//Get the collection of reflectable objects for this connection (the bin).//
			reflectables = (IList) binnedReflectables.get(connectionIdentifier);
			
			//Lazily create the reflectables collection for this bin.//
			if(reflectables == null) {
				reflectables = new LiteList(this.reflectables.getSize());
				binnedReflectables.put(connectionIdentifier, reflectables);
			}//if//
			
			//Add the reflectable value to the bin based on its related network connection.//
			reflectables.add(value);
		}//for//

		//Collect the sorted reflection data into the result list.//
		if(binnedReflectables != null) {
			IIterator connectionIdentifierIterator = binnedReflectables.keyIterator();
			
			while(connectionIdentifierIterator.hasNext()) {
				Object connectionIdentifier = connectionIdentifierIterator.next();
				IList reflectables = (IList) binnedReflectables.get(connectionIdentifier);
				
				//If this is the local process then collect the reflectable's reflection data, otherwise forward the agent to the remote process.//
				if(connectionIdentifier == null) {
					LiteHashMap resultMap = new LiteHashMap(reflectables.getSize());  //Note: Used to handle multiple requests for the same object.//
					
					for(int index = 0; index < reflectables.getSize(); index++) {
						IReflectable value = (IReflectable) reflectables.get(index);
						ReflectDataContainer reflectDataContainer = (ReflectDataContainer) resultMap.get(value);
						
						//If we haven't already created the reflection data then do so now (it is possible to have more than one reference to the same object in a collection).//
						if(reflectDataContainer == null) {
							reflectDataContainer = value.zzrReflectionRegister(updateHandler, new ReflectRegistrationData(metadataIndex, ReflectRegistrationData.OPTIONS_INCLUDE_REFLECTED_PROXY));
							
							if(reflectDataContainer != null) {
								resultMap.put(value, reflectDataContainer);
							}//if//
						}//if//
						
						result.add(reflectDataContainer);
					}//for//
				}//if//
				else {
					ReflectionCreationAgent agent = new ReflectionCreationAgent(reflectables, updateHandler, metadataIndex);
					IList reflectionData = null;
					
					//Send an agent to perform this same bit of code on the remote machine.//
					//TODO: Should handle exceptions?//
					reflectionData = (IList) Orb.sendAgent(agent, connectionIdentifier, false, 600000, null);
					
					if(reflectionData != null) {
						result.addAll(reflectionData);
					}//if//
				}//else//
			}//while//
		}//while//

		return result;
	}//run()//
	/* (non-Javadoc)
	 * @see java.io.Externalizable#readExternal(java.io.ObjectInput)
	 */
	public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
		/*byte version = */in.readByte();
		reflectables = (IList) in.readObject();
		updateHandler = (IReflectUpdateHandler) in.readObject();
		metadataIndex = (Class) in.readObject();
	}//readExternal()//
	/* (non-Javadoc)
	 * @see java.io.Externalizable#writeExternal(java.io.ObjectOutput)
	 */
	public void writeExternal(ObjectOutput out) throws IOException {
		out.writeByte(0);
		out.writeObject(reflectables);
		out.writeObject(updateHandler);
		out.writeObject(metadataIndex);
	}//writeExternal()//
}//ReflectionCreationAgent//