/**************************************************************************************
* 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 LGPL license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package examples.caching;
import java.util.HashMap;
import java.util.Map;
import org.codehaus.aspectwerkz.joinpoint.JoinPoint;
import org.codehaus.aspectwerkz.joinpoint.MethodSignature;
import org.codehaus.aspectwerkz.joinpoint.MethodRtti;
import org.codehaus.aspectwerkz.CrossCuttingInfo;
/**
* @author <a href="mailto:jboner@codehaus.org">Jonas Bon�r </a>
* @Aspect perInstance name=NAME
*/
public class CachingAspect {
/**
* The cross-cutting info.
*/
private final CrossCuttingInfo m_info;
/**
* The cache.
*/
private final Map m_cache = new HashMap();
/**
* We are interested in cross-cutting info, therefore we have added a constructor that takes a
* cross-cutting infor instance as its only parameter.
*
* @param info the cross-cutting info
*/
public CachingAspect(final CrossCuttingInfo info) {
m_info = info;
}
/**
* @Before call(int examples.caching.Pi.getPiDecimal(int)) && withincode(int
* examples.caching.main(String[]))
*/
public void invocationCounter(final JoinPoint joinPoint) throws Throwable {
MethodSignature signature = (MethodSignature) joinPoint.getSignature();
CacheStatistics.addMethodInvocation(signature.getName(), signature.getParameterTypes());
}
/**
* @Around execution(int examples.caching.Pi.getPiDecimal(int))
*/
public Object cache(final JoinPoint joinPoint) throws Throwable {
MethodRtti rtti = (MethodRtti) joinPoint.getRtti();
final Long hash = new Long(calculateHash(rtti));
final Object cachedResult = m_cache.get(hash);
if (cachedResult != null) {
System.out.println("using cache");
CacheStatistics.addCacheInvocation(rtti.getName(), rtti.getParameterTypes());
System.out.println("parameter: timeout = " + m_info.getParameter("timeout"));
return cachedResult;
}
final Object result = joinPoint.proceed();
m_cache.put(hash, result);
return result;
}
// ============ Utility methods ============
private long calculateHash(final MethodRtti rtti) {
int result = 17;
result = 37 * result + rtti.getName().hashCode();
Object[] parameters = rtti.getParameterValues();
for (int i = 0, j = parameters.length; i < j; i++) {
result = 37 * result + parameters[i].hashCode();
}
return result;
}
}