/**
    * Copyright 2010 The Kuali Foundation Licensed under the
    * Educational Community 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.osedu.org/licenses/ECL-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.kuali.student.common.test.spring;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import net.sf.ehcache.CacheManager;
  import net.sf.ehcache.Element;
  import net.sf.ehcache.ObjectExistsException;
  
  import org.aopalliance.aop.Advice;
  import org.apache.log4j.Logger;
  import org.aspectj.lang.ProceedingJoinPoint;
  
  public class IdToObjectEhcacheAdvice implements Advice {
  	final Logger LOG = Logger.getLogger(IdToObjectEhcacheAdvice.class);
  	
  	private CacheManager cacheManager;
  	private String cacheName;
  
  	/**
  	 * 
  	 */
  	public IdToObjectEhcacheAdvice() {
  		super();
  	}
  
  	/**
  	 * @param cacheName
  	 */
  	public IdToObjectEhcacheAdvice(String cacheName) {
  		super();
  		this.cacheName = cacheName;
  	}
  
  	public Object invalidateCache(ProceedingJoinPoint pjp) throws Throwable {
  		if (cacheManager == null) {
  			cacheManager = CacheManager.getInstance();
  			try {
  				cacheManager.addCache(cacheName);
  			} catch (ObjectExistsException e) {
  
  			}
  		}
  		LOG.info("Invalidating Cache");
  		cacheManager.getCache(cacheName).remove(pjp.getArgs()[0]);
  		return pjp.proceed();
  	}
  
  	@SuppressWarnings("unchecked")
  	public Object getFromCache(ProceedingJoinPoint pjp) throws Throwable {
  		if (cacheManager == null) {
  			cacheManager = CacheManager.getInstance();
  			try {
  				cacheManager.addCache(cacheName);
  			} catch (ObjectExistsException e) {
  
  			}
  		}
  		// Have two caches for the one object? one by id, the other by method
  		// call?
  		if (pjp.getArgs().length == 1 && pjp.getArgs()[0] instanceof List) {
  			List<Object> results = new ArrayList<Object>();
  			List<String> uncachedIdList = new ArrayList<String>();
  			for (String id : (List<String>) pjp.getArgs()[0]) {
  				// Look in the cache
  				LOG.info("Looking in Cache");
  				Element cachedResult = cacheManager.getCache(cacheName).get(id);
  				if (cachedResult == null) {
  					uncachedIdList.add(id);
  				} else {
  					results.add(cachedResult.getValue());
  				}
  			}
  			if (uncachedIdList.size() > 0) {
  				List<Idable> uncachedResults = (List<Idable>) pjp.proceed();
  				if (uncachedResults != null) {
  					for (Idable uncachedResult : uncachedResults) {
  						// Add to the cache and add to results
  						LOG.info("Storing to Cache");
  						results.add(uncachedResult);
  						cacheManager.getCache(cacheName).put(
  								new Element(uncachedResult.getId(),
  										uncachedResult));
  					}
 				}
 			}
 			return results;
 		}
 		if (pjp.getArgs().length == 1 && pjp.getArgs()[0] instanceof String) {
 			String id = (String) pjp.getArgs()[0];
 			LOG.info("Looking in Cache");
 			Element resultElement = cacheManager.getCache(cacheName).get(id);
 			Object result;
 			if (resultElement == null) {
 				result = pjp.proceed();
 				LOG.info("Storing to Cache");
 				cacheManager.getCache(cacheName).put(new Element(id, result));
 			} else {
 				result = resultElement.getValue();
 			}
 			return result;
 		}
 
 		return pjp.proceed();
 	}
 
 	/**
 	 * @return the cacheName
 	 */
 	public String getCacheName() {
 		return cacheName;
 	}
 
 	/**
 	 * @param cacheName
 	 *            the cacheName to set
 	 */
 	public void setCacheName(String cacheName) {
 		this.cacheName = cacheName;
 	}
 
 }