com.googlecode.ehcache.annotations.impl.ExpiredElementEvictor.java Source code

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Here is the source code for com.googlecode.ehcache.annotations.impl.ExpiredElementEvictor.java

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/**
 * 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.impl;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.Timer;
import java.util.TimerTask;

import net.sf.ehcache.CacheManager;
import net.sf.ehcache.Ehcache;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;

/**
 * {@link TimerTask} implementation that depends on a {@link CacheManager}
 * reference.
 * When {@link #run()} is invoked, {@link Ehcache#evictExpiredElements()}
 * is invoked on each cache identified by the cacheNames field.
 * 
 * @author Nicholas Blair
 * @version $Id$
 */
public final class ExpiredElementEvictor extends TimerTask implements InitializingBean, DisposableBean {

    private static final long MILLIS_PER_MINUTE = 60 * 1000L;
    private CacheManager cacheManager;
    private List<CacheNameMatcher> cacheNameMatchers = new ArrayList<CacheNameMatcher>();
    private Timer timer;
    private long interval;
    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    /**
     * @param cacheManager the cacheManager to set
     */
    public void setCacheManager(CacheManager cacheManager) {
        this.cacheManager = cacheManager;
    }

    /**
     * @param cacheNameMatchers the cacheNameMatchers to set
     */
    public void setCacheNameMatchers(List<CacheNameMatcher> cacheNameMatchers) {
        this.cacheNameMatchers = cacheNameMatchers;
    }

    /**
     * @param interval the interval evict expired elements, in minutes
     */
    public void setInterval(int interval) {
        this.interval = interval * MILLIS_PER_MINUTE;
    }

    /**
     * @return the cacheNameMatchers
     */
    public List<CacheNameMatcher> getCacheNameMatchers() {
        return cacheNameMatchers;
    }

    /**
     * @return the interval
     */
    public int getInterval() {
        return (int) (this.interval / MILLIS_PER_MINUTE);
    }

    /*
     * (non-Javadoc)
     * @see java.util.TimerTask#run()
     */
    @Override
    public void run() {
        final long startTime = System.currentTimeMillis();

        final String[] cacheNames = this.cacheManager.getCacheNames();
        final Set<String> evictableCacheNames = this.calculateEvictableCacheNames(cacheNames);

        long evictedTotal = 0;
        for (String cacheName : evictableCacheNames) {
            Ehcache cache = this.cacheManager.getEhcache(cacheName);
            if (null != cache) {
                long preEvictSize = cache.getMemoryStoreSize();
                long evictStart = System.currentTimeMillis();
                cache.evictExpiredElements();
                if (logger.isDebugEnabled()) {
                    long evicted = preEvictSize - cache.getMemoryStoreSize();
                    evictedTotal += evicted;
                    logger.debug("Evicted " + evicted + " elements from cache '" + cacheName + "' in "
                            + (System.currentTimeMillis() - evictStart) + " ms");
                }
            } else {
                if (logger.isDebugEnabled()) {
                    logger.debug("no cache found with name " + cacheName);
                }
            }
        }

        if (logger.isDebugEnabled()) {
            logger.debug("Evicted " + evictedTotal + " elements from " + evictableCacheNames.size() + " caches  in "
                    + (System.currentTimeMillis() - startTime) + " ms");
        }
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
     */
    public void afterPropertiesSet() throws Exception {
        if (null == this.cacheManager) {
            throw new IllegalStateException("cacheManager reference must be set");
        }

        timer = new Timer(this.cacheManager.getName() + "expiredElementEvictorTimer", true);
        timer.schedule(this, interval, interval);
    }

    /* (non-Javadoc)
     * @see org.springframework.beans.factory.DisposableBean#destroy()
     */
    public void destroy() throws Exception {
        this.timer.cancel();
    }

    /**
     * @return Get the set of caches to do eviction for based on the full array of cache names in the cache manager
     */
    protected Set<String> calculateEvictableCacheNames(final String[] cacheManagerCacheNames) {
        Set<String> result = new HashSet<String>();
        // from the list of matchers, calculate the cacheNames set
        for (String cacheManagerCacheName : cacheManagerCacheNames) {
            Vote vote = null;
            for (CacheNameMatcher matcher : this.cacheNameMatchers) {
                vote = matcher.matches(cacheManagerCacheName);
                if (Vote.ABSTAIN.equals(vote)) {
                    continue;
                } else if (Vote.YEA.equals(vote)) {
                    result.add(cacheManagerCacheName);
                } else {
                    result.remove(cacheManagerCacheName);
                }
            }
        }

        return result;
    }
}