DataCacheFactory.java

/**************************************************************************************
 * Copyright (C) 2008 EsperTech, Inc. All rights reserved.                            *
 * http://esper.codehaus.org                                                          *
 * http://www.espertech.com                                                           *
 * ---------------------------------------------------------------------------------- *
 * The software in this package is published under the terms of the GPL license       *
 * a copy of which has been included with this distribution in the license.txt file.  *
 **************************************************************************************/
package com.espertech.esper.epl.db;

import com.espertech.esper.client.ConfigurationDataCache;
import com.espertech.esper.client.ConfigurationLRUCache;
import com.espertech.esper.client.ConfigurationExpiryTimeCache;
import com.espertech.esper.core.context.util.EPStatementAgentInstanceHandle;
import com.espertech.esper.schedule.ScheduleBucket;
import com.espertech.esper.schedule.SchedulingService;

/**
 * Factory for data caches for use caching database query results and method invocation results.
 */
public class DataCacheFactory
{
    /**
     * Creates a cache implementation for the strategy as defined by the cache descriptor.
     * @param cacheDesc cache descriptor
     * @param epStatementAgentInstanceHandle statement handle for timer invocations
     * @param schedulingService scheduling service for time-based caches
     * @param scheduleBucket for ordered timer invokation
     * @return data cache implementation
     */
    public static DataCache getDataCache(ConfigurationDataCache cacheDesc,
                                         EPStatementAgentInstanceHandle epStatementAgentInstanceHandle,
                                         SchedulingService schedulingService,
                                         ScheduleBucket scheduleBucket)
    {
        if (cacheDesc == null)
        {
            return new DataCacheNullImpl();
        }

        if (cacheDesc instanceof ConfigurationLRUCache)
        {
            ConfigurationLRUCache lruCache = (ConfigurationLRUCache) cacheDesc;
            return new DataCacheLRUImpl(lruCache.getSize());
        }

        if (cacheDesc instanceof ConfigurationExpiryTimeCache)
        {
            ConfigurationExpiryTimeCache expCache = (ConfigurationExpiryTimeCache) cacheDesc;
            return new DataCacheExpiringImpl(expCache.getMaxAgeSeconds(), expCache.getPurgeIntervalSeconds(), expCache.getCacheReferenceType(),
                    schedulingService, scheduleBucket.allocateSlot(), epStatementAgentInstanceHandle);
        }

        throw new IllegalStateException("Cache implementation class not configured");
    }
}