Java tutorial
package net.nelz.simplesm.aop; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Pointcut; import org.aspectj.lang.annotation.AfterReturning; import org.aspectj.lang.JoinPoint; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import java.lang.reflect.Method; import net.nelz.simplesm.api.UpdateAssignCache; /** Copyright (c) 2008, 2009 Nelson Carpentier Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ @Aspect public class UpdateAssignCacheAdvice extends CacheBase { private static final Log LOG = LogFactory.getLog(UpdateAssignCacheAdvice.class); @Pointcut("@annotation(net.nelz.simplesm.api.UpdateAssignCache)") public void updateAssign() { } @AfterReturning(pointcut = "updateAssign()", returning = "retVal") public Object cacheUpdateAssign(final JoinPoint jp, final Object retVal) throws Throwable { // This is injected caching. If anything goes wrong in the caching, LOG the crap outta it, // but do not let it surface up past the AOP injection itself. try { final Method methodToCache = getMethodToCache(jp); final UpdateAssignCache annotation = methodToCache.getAnnotation(UpdateAssignCache.class); final AnnotationData annotationData = AnnotationDataBuilder.buildAnnotationData(annotation, UpdateAssignCache.class, methodToCache); final String cacheKey = buildCacheKey(annotationData.getAssignedKey(), annotationData); final Object dataObject = annotationData.getDataIndex() == -1 ? retVal : getIndexObject(annotationData.getDataIndex(), jp, methodToCache); final Object submission = (dataObject == null) ? new PertinentNegativeNull() : dataObject; cache.set(cacheKey, annotationData.getExpiration(), submission); } catch (Exception ex) { LOG.warn("Updating caching via " + jp.toShortString() + " aborted due to an error.", ex); } return retVal; } }