lovflushinterceptor.java

来自「一个很好的开源项目管理系统源代码」· Java 代码 · 共 85 行

package net.java.workeffort.service.support;

import java.lang.reflect.Method;

import net.java.workeffort.infrastructure.cache.ICacheController;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.aop.AfterReturningAdvice;

/**
 * Interceptor which flushes cache keys of lovs.
 * <p>
 * This implements an 'after returning' advise. When methods are invoked on a
 * service which modify values pertaining to a cached lov, this advise will
 * invalidate the cache entry for the pertinent lov. The next time the lov is
 * accessed no value will be available in the cache and the database will be
 * accessed to get the latest values. This interceptor has to be configured for
 * the appropriate services in Spring.
 * <p>
 * Note: The cache keys have the format: getCached*Lov (example
 * "getCachedDeliverableLov" ) and assumes that the service method names which
 * need to invalidate the lov cache have the format "insert*" or "update*" or
 * "delete*" (example insertDeliverable, updateDeliverable, deleteDeliverable)
 * @author Antony Joseph
 */

public class LovFlushInterceptor implements AfterReturningAdvice {
    private static final Log logger = LogFactory
            .getLog(LovFlushInterceptor.class);

    private ICacheController cacheController;

    /**
     * Advise which invalidates a cache entry for an lov
     * @param returnObj The object returned from invoking the method on the
     *            service layer
     * @param method The method invoked on the service layer
     * @param args The arguments to the method invoked on the service layer
     * @param target The target object the above method was invoked on.
     */
    public void afterReturning(Object returnObj, Method method, Object[] args,
            Object target) throws Throwable {

        // get the part of the method name after "insert" or "update" and create
        // the cache key from it.
        StringBuffer cacheKey = new StringBuffer(100);
        String methodSuffix = null;
        if (StringUtils.substringAfter(method.getName(), "insert").length() > 0) {
            methodSuffix = StringUtils.substringAfter(method.getName(),
                    "insert");
        }
        else if (StringUtils.substringAfter(method.getName(), "update")
                .length() > 0) {
            methodSuffix = StringUtils.substringAfter(method.getName(),
                    "update");
        }
        else if (StringUtils.substringAfter(method.getName(), "delete")
                .length() > 0) {
            methodSuffix = StringUtils.substringAfter(method.getName(),
                    "delete");
        }

        cacheKey.append("getCached");
        cacheKey.append(methodSuffix);
        cacheKey.append("Lov");

        if (logger.isInfoEnabled()) {
            logger.info("LovFlushInterceptor.afterReturning() invoked. method="
                    + method.getName() + ". Invalidating cacheKey=" + cacheKey);
        }

        cacheController.removeObject(cacheKey.toString());

    }

    /**
     * @param cacheController The cacheController to set. IOC
     */
    public void setCacheController(ICacheController cacheController) {
        this.cacheController = cacheController;
    }

}