de.dan_nrw.caching.CachingAspect.java Source code

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Here is the source code for de.dan_nrw.caching.CachingAspect.java

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/* 
 * de.dan_nrw.caching
 * 
 * Copyright (C) 2010, Daniel Czerwonk <d.czerwonk@googlemail.com>
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package de.dan_nrw.caching;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;

/**
 * @author Daniel Czerwonk
 *
 */
@Aspect
public class CachingAspect {

    @Pointcut("execution(@Cachable * *(..))")
    void cachablePointcut() {

    }

    @Around("cachablePointcut()")
    public Object aroundCachable(final ProceedingJoinPoint joinPoint) throws Throwable {
        MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();
        Cachable cachableAnnotation = (Cachable) methodSignature.getMethod().getAnnotation(Cachable.class);
        Cache cache = Cache.getCurrent();

        try {
            if (cache.containsKey(cachableAnnotation.key())) {
                // if key is already in cache and data is not expired
                return cache.get(cachableAnnotation.key());
            }
        } catch (IllegalArgumentException ex) {
            // if key does not exists, data must be retrieved
        } catch (CachedDataExpiredException ex) {
            // if data stored in cache is expired, it must be retrieved
        }

        // determinig data
        Object data = joinPoint.proceed();

        // cache is filled
        if (data != null) {
            cache.put(cachableAnnotation.key(), data, cachableAnnotation.durability());
        }

        // returning result
        return data;
    }
}