com.googlecode.ehcache.annotations.CacheableInterceptor Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of ehcache-spring-annotations Show documentation
Provides a simple model for integrating Ehcache in a Spring project via annotations.
The newest version!
/**
 * Copyright 2010-2011 Nicholas Blair, Eric Dalquist
 *
 * 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 com.googlecode.ehcache.annotations;

import java.io.Serializable;

import net.sf.ehcache.Ehcache;

import org.aopalliance.intercept.MethodInvocation;

/**
 * Used by {@link Cacheable} to allow logic to be injected into the caching API.
 * 
 * Normal execution workflow looks like:
 * 
 * 
 * Generate cache key 
 * Cache lookup
 * If Cache lookup finds an entry for the key, {@link #preInvokeCachable(Ehcache, MethodInvocation, Serializable, Object)} is called
 * 	 If preInvokeCachable returns false the cached value is returned       
 * Proceed with method invocation and capture the returned value
 * Call {@link #postInvokeCacheable(Ehcache, MethodInvocation, Serializable, Object)}
 * If postInvokeCacheable returns true the value is cached
 * Return the value
 * 
 * 
 * Exception execution workflow looks like (as long as {@link Cacheable#exceptionCacheName()} is defined):
 * 
 * 
 * Generate cache key
 * Exception cache lookup
 * If lookup finds an exception {@link #preInvokeCacheableException(Ehcache, MethodInvocation, Serializable, Throwable)} is called
 * 	 If preInvokeCacheableException returns false the cached exception is thrown      
 * Cache lookup
 * If lookup finds an entry {@link #preInvokeCachable(Ehcache, MethodInvocation, Serializable, Object)} is called
 *   If preInvokeCachable returns false the cached value is returned 
 * Proceed with method invocation and capture the returned value
 * If an exception is thrown by the method invocation:
 *  	
 *        Call {@link #postInvokeCacheableException(Ehcache, MethodInvocation, Serializable, Throwable)}
 *        If postInvokeCacheableException returns true the exception is cached
 *        Throw the exception
 *      
 * Else:
 * 		
 *        Call {@link #postInvokeCacheable(Ehcache, MethodInvocation, Serializable, Object)}
 *        If postInvokeCacheable returns true the value is cached
 *        Return the value
 *      
 * 
 * 
 * @author Eric Dalquist
 * @version $Revision: 656 $
 */
public interface CacheableInterceptor {
    /**
     * Called after a cache hit but before the method invocation.
     * 
     * Not used when {@link Cacheable#selfPopulating()} is set to true.
     * 
     * @param cache The cache used for this invocation
     * @param methodInvocation The method invocation that has been intercepted
     * @param key The generated cache key
     * @param value The found cache value if any, may be null
     * @return true if the intercepted method invocation should be invoked, false if it should not be invoked and the value should be returned.
     */
    public boolean preInvokeCachable(Ehcache cache, MethodInvocation methodInvocation, Serializable key, Object value);
    
    /**
     * Called after a method invocation but before the returned value is cached
     * 
     * Not used when {@link Cacheable#selfPopulating()} is set to true.
     * 
     * @param cache The cache used for this invocation
     * @param methodInvocation The method invocation that has been intercepted
     * @param key The generated cache key
     * @param value The value returned by the invocation
     * @return true if the value should be cached, false if not
     */
    public boolean postInvokeCacheable(Ehcache cache, MethodInvocation methodInvocation, Serializable key, Object value);
    
    /**
     * Called after the cache lookup but before the method invocation if a cached exception was found
     * 
     * @param exceptionCache The cache used for this invocation
     * @param methodInvocation The method invocation that has been intercepted
     * @param key The generated cache key
     * @param t The exception thrown by the invocation
     * @return true if the intercepted method invocation should be invoked, false if it should not be invoked and the cached exception thrown.
     */
    public boolean preInvokeCacheableException(Ehcache exceptionCache, MethodInvocation methodInvocation, Serializable key, Throwable t);
    
    
    /**
     * Called after a method invocation throws an exception AND an exception cache is configured for the
     * interceptor but before the exception is cached
     * 
     * @param exceptionCache The cache used for this invocation
     * @param methodInvocation The method invocation that has been intercepted
     * @param key The generated cache key
     * @param t The exception thrown by the invocation
     * @return true if the exception should be cached, false if not
     */
    public boolean postInvokeCacheableException(Ehcache exceptionCache, MethodInvocation methodInvocation, Serializable key, Throwable t);
}