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mchange-commons-java
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/*
 * Distributed as part of mchange-commons-java v.0.2.3
 *
 * Copyright (C) 2012 Machinery For Change, Inc.
 *
 * Author: Steve Waldman 
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 2.1, as 
 * published by the Free Software Foundation.
 *
 * This software 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this software; see the file LICENSE.  If not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 */


package com.mchange.v1.cachedstore;

import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.lang.reflect.InvocationHandler;

/**
 * Unless otherwise noted, implementations are to be presumed
 * NOT thread safe!!! use the synchronized
 * wrappers defined in CachedStoreUtils for multithreaded situations!
 *
 * @see CachedStoreUtils#synchronizedCachedStore
 * @see CachedStoreUtils#synchronizedTweakableCachedStore
 */
public final class CachedStoreFactory
{
    public static TweakableCachedStore createNoCleanupCachedStore(CachedStore.Manager manager)
    { return new NoCleanupCachedStore( manager ); }

    /**
     *  Better to use createSynchronousCleanupSoftKeyCachedStore to prevent the build of 
     *  cleaned SoftReferences, unless the universe of potential cacheables is small.
     */
    public static TweakableCachedStore createSoftValueCachedStore(CachedStore.Manager manager)
    { return new SoftReferenceCachedStore( manager ); }

    public static TweakableCachedStore createSynchronousCleanupSoftKeyCachedStore(CachedStore.Manager manager)
    { 
	final ManualCleanupSoftKeyCachedStore inner = new ManualCleanupSoftKeyCachedStore( manager ); 
	InvocationHandler handler = new InvocationHandler()
	    {
		public Object invoke(Object proxy, Method m, Object[] args) 
		    throws Throwable
		{
		    inner.vacuum();
		    return m.invoke( inner, args ); 
		}
	    };
	return (TweakableCachedStore) Proxy.newProxyInstance( CachedStoreFactory.class.getClassLoader(),
							      new Class[] { TweakableCachedStore.class },
							      handler );
    }

    /**
     *  Always reads directly from manager, as if values are always dirty.
     */
    public static TweakableCachedStore createNoCacheCachedStore( CachedStore.Manager mgr )
    { return new NoCacheCachedStore( mgr ); }

    /**
     * creates a WritableCachedStore implementation that uses soft keys and synchronous
     * cleanup for its read cache.
     */
    public static WritableCachedStore createDefaultWritableCachedStore(WritableCachedStore.Manager manager)
    {
	TweakableCachedStore readOnlyCache = createSynchronousCleanupSoftKeyCachedStore( manager );
	return new SimpleWritableCachedStore( readOnlyCache, manager );
    }

    public static WritableCachedStore cacheWritesOnlyWritableCachedStore( WritableCachedStore.Manager mgr )
    { 
	TweakableCachedStore readOnlyCache = createNoCacheCachedStore( mgr );
	return new SimpleWritableCachedStore( readOnlyCache, mgr );
    }

    /**
     *  Always reads directly from manager, as if values are always dirty. Always
     *  writes to back-end storage. Effectively Autoflushing, since every write
     *  is flushed.
     *
     *  @see Autoflushing 
     */
    public static WritableCachedStore createNoCacheWritableCachedStore( WritableCachedStore.Manager mgr )
    { return new NoCacheWritableCachedStore( mgr ); }
}