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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.ref.Reference;
import java.lang.ref.SoftReference;
import java.util.HashMap;
import java.util.Map;
import java.util.Iterator;

/**
 * by default, this class is NOT thread safe!!! use the synchronized
 * wrappers defined in CachedStoreUtils for multithreaded situations!
 *
 * @see CachedStoreUtils#synchronizedCachedStore
 * @see CachedStoreUtils#synchronizedTweakableCachedStore
 */
class SoftReferenceCachedStore extends ValueTransformingCachedStore
{
    public SoftReferenceCachedStore(CachedStore.Manager manager)
    { super( manager ); }

    protected Object toUserValue( Object cacheValue )
    { return cacheValue == null ? null : ((SoftReference) cacheValue).get(); }

    protected Object toCacheValue( Object userValue )
    { return userValue == null ? null : new SoftReference( userValue ); }

}