/* * Copyright 2002-2004 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.taha.interceptor;
import java.io.Serializable;
import org.aopalliance.intercept.MethodInterceptor; import org.aopalliance.intercept.MethodInvocation;
import org.apache.commons.logging.LogFactory; import org.apache.commons.logging.Log;
import org.springframework.beans.factory.InitializingBean; import org.springframework.util.Assert;
import net.sf.ehcache.Cache; import net.sf.ehcache.Element;
/** * @author <a href=" mailto:irbouh@gmail.com">Omar Irbouh</a> * @since 2004.10.07 */ public class MethodCacheInterceptor implements MethodInterceptor, InitializingBean { private static final Log logger = LogFactory.getLog(MethodCacheInterceptor.class);
private Cache cache;
/** * 设置缓存名 */ public void setCache(Cache cache) { this.cache = cache; }
/** * 检查是否提供必要参数。 */ public void afterPropertiesSet() throws Exception { Assert.notNull(cache, "A cache is required. Use setCache(Cache) to provide one."); }
/** * 主方法 * 如果某方法可被缓存就缓存其结果 * 方法结果必须是可序列化的(serializable) */ public Object invoke(MethodInvocation invocation) throws Throwable { String targetName = invocation.getThis().getClass().getName(); String methodName = invocation.getMethod().getName(); Object[] arguments = invocation.getArguments(); Object result;
logger.debug("looking for method result in cache"); String cacheKey = getCacheKey(targetName, methodName, arguments); Element element = cache.get(cacheKey); if (element == null) { //call target/sub-interceptor logger.debug("calling intercepted method"); result = invocation.proceed();
//cache method result logger.debug("caching result"); element = new Element(cacheKey, (Serializable) result); cache.put(element); } return element.getValue(); }
/** * creates cache key: targetName.methodName.argument0.argument1... */ private String getCacheKey(String targetName, String methodName, Object[] arguments) { StringBuffer sb = new StringBuffer(); sb.append(targetName) .append(".").append(methodName); if ((arguments != null) && (arguments.length != 0)) { for (int i=0; i<arguments.length; i++) { sb.append(".") .append(arguments[i]); } }
return sb.toString(); } } |