com.mchange.v1.cachedstore.KeyTransformingCachedStore Maven / Gradle / Ivy
/*
* Distributed as part of mchange-commons-java 0.2.11
*
* Copyright (C) 2015 Machinery For Change, Inc.
*
* Author: Steve Waldman
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of EITHER:
*
* 1) The GNU Lesser General Public License (LGPL), version 2.1, as
* published by the Free Software Foundation
*
* OR
*
* 2) The Eclipse Public License (EPL), version 1.0
*
* You may choose which license to accept if you wish to redistribute
* or modify this work. You may offer derivatives of this work
* under the license you have chosen, or you may provide the same
* choice of license which you have been offered here.
*
* 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.
*
* You should have received copies of both LGPL v2.1 and EPL v1.0
* along with this software; see the files LICENSE-EPL and LICENSE-LGPL.
* If not, the text of these licenses are currently available at
*
* LGPL v2.1: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* EPL v1.0: http://www.eclipse.org/org/documents/epl-v10.php
*
*/
package com.mchange.v1.cachedstore;
import java.util.Iterator;
import com.mchange.v1.util.WrapperIterator;
abstract class KeyTransformingCachedStore extends NoCleanupCachedStore
{
protected KeyTransformingCachedStore( CachedStore.Manager manager )
{ super( manager ); }
public Object getCachedValue(Object key)
{ return cache.get( toCacheFetchKey( key ) ); }
public void removeFromCache(Object key)
throws CachedStoreException
{ cache.remove( toCacheFetchKey( key ) ); }
public void setCachedValue(Object key, Object value)
throws CachedStoreException
{
//System.err.println("setCachedValue( " + key + " , " + value + " )");
Object newKey = toCachePutKey( key );
//System.err.println("put( " + newKey + " , " + value + " )");
cache.put( newKey , value );
}
public Iterator cachedKeys() throws CachedStoreException
{
return new WrapperIterator( cache.keySet().iterator(), false )
{
public Object transformObject( Object o )
{
Object out = toUserKey( o );
return ( out == null ? SKIP_TOKEN : out );
}
};
}
protected Object toUserKey( Object cachePutKey )
{ return cachePutKey; }
/**
* @return the key that will be used for gets and removes to the
* inner HashMap
*/
protected Object toCacheFetchKey( Object userKey )
{ return toCachePutKey( userKey ); }
/**
* @return the key that will be used for puts into the
* inner HashMap
*/
protected Object toCachePutKey( Object userKey )
{ return userKey; }
protected Object removeByTransformedKey( Object cacheFetchKey )
{ return cache.remove( cacheFetchKey ); }
}