/*
    * Copyright 2006-2007 the original author or authors.
    *
    * 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.springframework.batch.repeat.policy;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  
  import org.springframework.batch.repeat.CompletionPolicy;
  import org.springframework.batch.repeat.RepeatContext;
  import org.springframework.batch.repeat.RepeatStatus;
  import org.springframework.batch.repeat.context.RepeatContextSupport;
  
  /**
   * Composite policy that loops through a list of delegate policies and answers
   * calls by a concensus.
   * 
   * @author Dave Syer
   * 
   */
  public class CompositeCompletionPolicy implements CompletionPolicy {
  
  	CompletionPolicy[] policies = new CompletionPolicy[0];
  
  	/**
  	 * Setter for the policies.
  	 * 
  	 * @param policies
  	 */
  	public void setPolicies(CompletionPolicy[] policies) {
  		this.policies = Arrays.asList(policies).toArray(new CompletionPolicy[policies.length]);
  	}
  
  	/**
  	 * This policy is complete if any of the composed policies is complete.
  	 * 
  	 * @see org.springframework.batch.repeat.CompletionPolicy#isComplete(org.springframework.batch.repeat.RepeatContext,
  	 * RepeatStatus)
  	 */
      @Override
  	public boolean isComplete(RepeatContext context, RepeatStatus result) {
  		RepeatContext[] contexts = ((CompositeBatchContext) context).contexts;
  		CompletionPolicy[] policies = ((CompositeBatchContext) context).policies;
  		for (int i = 0; i < policies.length; i++) {
  			if (policies[i].isComplete(contexts[i], result)) {
  				return true;
  			}
  		}
  		return false;
  	}
  
  	/**
  	 * This policy is complete if any of the composed policies is complete.
  	 * 
  	 * @see org.springframework.batch.repeat.CompletionPolicy#isComplete(org.springframework.batch.repeat.RepeatContext)
  	 */
      @Override
  	public boolean isComplete(RepeatContext context) {
  		RepeatContext[] contexts = ((CompositeBatchContext) context).contexts;
  		CompletionPolicy[] policies = ((CompositeBatchContext) context).policies;
  		for (int i = 0; i < policies.length; i++) {
  			if (policies[i].isComplete(contexts[i])) {
  				return true;
  			}
  		}
  		return false;
  	}
  
  	/**
  	 * Create a new composite context from all the available policies.
  	 * 
  	 * @see org.springframework.batch.repeat.CompletionPolicy#start(RepeatContext)
  	 */
      @Override
  	public RepeatContext start(RepeatContext context) {
  		List<RepeatContext> list = new ArrayList<RepeatContext>();
  		for (int i = 0; i < policies.length; i++) {
  			list.add(policies[i].start(context));
  		}
  		return new CompositeBatchContext(context, list);
  
  	}
  
  	/**
  	 * Update all the composed contexts, and also increment the parent context.
 	 * 
 	 * @see org.springframework.batch.repeat.CompletionPolicy#update(org.springframework.batch.repeat.RepeatContext)
 	 */
     @Override
 	public void update(RepeatContext context) {
 		RepeatContext[] contexts = ((CompositeBatchContext) context).contexts;
 		CompletionPolicy[] policies = ((CompositeBatchContext) context).policies;
 		for (int i = 0; i < policies.length; i++) {
 			policies[i].update(contexts[i]);
 		}
 		((RepeatContextSupport) context).increment();
 	}
 
 	/**
 	 * Composite context that knows about the policies and contexts is was
 	 * created with.
 	 * 
 	 * @author Dave Syer
 	 * 
 	 */
 	protected class CompositeBatchContext extends RepeatContextSupport {
 
 		private RepeatContext[] contexts;
 
 		// Save a reference to the policies when we were created - gives some
 		// protection against reference changes (e.g. if the number of policies
 		// change).
 		private CompletionPolicy[] policies;
 
 		public CompositeBatchContext(RepeatContext context, List<RepeatContext> contexts) {
 			super(context);
 			this.contexts = contexts.toArray(new RepeatContext[contexts.size()]);
 			this.policies = CompositeCompletionPolicy.this.policies;
 		}
 
 	}
 
 }