/**************************************************************************************
* Copyright (c) Jonas Bon�r, Alexandre Vasseur. All rights reserved. *
* http://aspectwerkz.codehaus.org *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the QPL license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package examples.xmldef.caching;
import java.util.Map;
import java.util.HashMap;
import org.codehaus.aspectwerkz.xmldef.advice.AroundAdvice;
import org.codehaus.aspectwerkz.joinpoint.JoinPoint;
import org.codehaus.aspectwerkz.joinpoint.MethodJoinPoint;
/**
* This advice implements a simple caching service.<br/>
*
* It caches the results from the method invocations that are picked out
* by the pointcuts mapped to this advice.
*
* @author <a href="mailto:jboner@codehaus.org">Jonas Bon�r</a>
*/
public class CachingAdvice extends AroundAdvice {
// public static final int NR_OF_BUCKETS = 1000;
// protected Map m_cache = new StaticBucketMap(NR_OF_BUCKETS);
protected Map m_cache = new HashMap();
public CachingAdvice() {
super();
}
public Object execute(final JoinPoint joinPoint) throws Throwable {
MethodJoinPoint jp = (MethodJoinPoint)joinPoint;
final Long hash = new Long(calculateHash(jp));
final Object cachedResult = m_cache.get(hash);
if (cachedResult != null) {
System.out.println("using cache");
CacheStatistics.addCacheInvocation(jp.getMethodName(), jp.getParameterTypes());
return cachedResult;
}
final Object result = joinPoint.proceed();
m_cache.put(hash, result);
return result;
}
private long calculateHash(final MethodJoinPoint jp) {
int result = 17;
result = 37 * result + jp.getMethodName().hashCode();
Object[] parameters = jp.getParameters();
for (int i = 0, j = parameters.length; i < j; i++) {
result = 37 * result + parameters[i].hashCode();
}
return result;
}
}