JavaxCacheQueryResultCache.java

/**********************************************************************
Copyright (c) 2012 Andy Jefferson and others. All rights reserved.
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.

Contributors:
   ...
**********************************************************************/
package org.datanucleus.cache;

import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.cache.Cache;
import javax.cache.CacheException;
import javax.cache.CacheManager;
import javax.cache.Caching;
import javax.cache.configuration.Configuration;
import javax.cache.configuration.MutableConfiguration;
import javax.cache.spi.CachingProvider;

import org.datanucleus.NucleusContext;
import org.datanucleus.exceptions.NucleusException;
import org.datanucleus.query.QueryUtils;
import org.datanucleus.store.query.Query;
import org.datanucleus.store.query.cache.QueryResultsCache;
import org.datanucleus.util.NucleusLogger;

/**
 * Implementation of a query results cache using javax.cache (v0.3+) interface.
 */
public class JavaxCacheQueryResultCache implements QueryResultsCache
{
    private static final long serialVersionUID = -3967431477335678467L;
    /** The cache to use. */
    private Cache cache;

    /**
     * Constructor.
     * @param nucleusCtx Context
     */
    public JavaxCacheQueryResultCache(NucleusContext nucleusCtx)
    {
        org.datanucleus.Configuration conf = nucleusCtx.getConfiguration();
        String cacheName = conf.getStringProperty("datanucleus.cache.queryResults.cacheName");
        if (cacheName == null)
        {
            NucleusLogger.CACHE.warn("No 'datanucleus.cache.queryResults.cacheName' specified so using name of 'DataNucleus-Query'");
            cacheName = "datanucleus-query";
        }
        try
        {
            CachingProvider cacheProvider = Caching.getCachingProvider();
            CacheManager cacheMgr = cacheProvider.getCacheManager();
            Cache tmpcache = cacheMgr.getCache(cacheName);
            if (tmpcache == null)
            {
                Configuration cacheConfig = new MutableConfiguration();
                // TODO Allow specification of config of the cache
                cacheMgr.createCache(cacheName, cacheConfig);
                tmpcache = cacheMgr.getCache(cacheName);
            }
            cache = tmpcache;
        }
        catch (CacheException e)
        {
            throw new NucleusException("Error creating cache", e);
        }
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#close()
     */
    public void close()
    {
        evictAll();
        cache = null;
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#contains(java.lang.String)
     */
    public boolean contains(String queryKey)
    {
        return get(queryKey) != null;
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#evict(java.lang.Class)
     */
    public void evict(Class candidate)
    {
        // TODO Auto-generated method stub
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#evict(org.datanucleus.store.query.Query)
     */
    public synchronized void evict(Query query)
    {
        String baseKey = QueryUtils.getKeyForQueryResultsCache(query, null);
        Iterator<Cache.Entry> entryIter = cache.iterator();
        while (entryIter.hasNext())
        {
            Cache.Entry entry = entryIter.next();
            String key = (String)entry.getKey();
            if (key.startsWith(baseKey))
            {
                entryIter.remove();
            }
        }
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#evict(org.datanucleus.store.query.Query, java.util.Map)
     */
    public synchronized void evict(Query query, Map params)
    {
        String key = QueryUtils.getKeyForQueryResultsCache(query, params);
        cache.remove(key);
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#clear()
     */
    public synchronized void evictAll()
    {
        cache.removeAll();
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#pin(org.datanucleus.store.query.Query, java.util.Map)
     */
    public void pin(Query query, Map params)
    {
        return;
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#pin(org.datanucleus.store.query.Query)
     */
    public void pin(Query query)
    {
        return;
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#unpin(org.datanucleus.store.query.Query, java.util.Map)
     */
    public void unpin(Query query, Map params)
    {
        return;
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#unpin(org.datanucleus.store.query.Query)
     */
    public void unpin(Query query)
    {
        return;
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#get(java.lang.String)
     */
    public List<Object> get(String queryKey)
    {
        return (List<Object>) cache.get(queryKey);
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#isEmpty()
     */
    public boolean isEmpty()
    {
        return size() == 0;
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#put(java.lang.String, java.util.List)
     */
    public synchronized List<Object> put(String queryKey, List<Object> results)
    {
        if (queryKey == null || results == null)
        {
            return null;
        }

        try
        {
            cache.put(queryKey, results);
        }
        catch (RuntimeException re)
        {
            // Not cached for some reason. Not serializable?
            NucleusLogger.CACHE.info("Query results with key '" + queryKey + "' not cached. " + re.getMessage());
        }
        return results;
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.query.cache.QueryResultsCache#size()
     */
    public int size()
    {
        // TODO Implement this
        throw new UnsupportedOperationException("size() method not supported by this plugin");
    }
}