// GenericsNote: Converted.
/*
* Copyright 2001-2004 The Apache Software Foundation
*
* 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.
*/
package org.apache.commons.collections15.functors;
import java.io.Serializable;
import java.util.Map;
import org.apache.commons.collections15.Transformer;
/**
* Transformer implementation that returns the value held in a specified map
* using the input parameter as a key.
*
* @author Matt Hall, John Watkinson, Stephen Colebourne
* @version $Revision: 1.1 $ $Date: 2005/10/11 17:05:24 $
* @since Commons Collections 3.0
*/
public final class MapTransformer<I, O>
implements Transformer<I, O>, Serializable {
/**
* Serial version UID
*/
static final long serialVersionUID = 862391807045468939L;
/**
* The map of data to lookup in
*/
private final Map<I, O> iMap;
/**
* Factory to create the transformer.
* <p/>
* If the map is null, a transformer that always returns null is returned.
*
* @param map
* the map, not cloned
* @return the transformer
*/
public static <I, O> Transformer<I, O> getInstance(Map<I, O> map) {
if (map == null) {
return ConstantTransformer.NULL_INSTANCE;
}
return new MapTransformer<I, O>(map);
}
/**
* Constructor that performs no validation. Use <code>getInstance</code> if
* you want that.
*
* @param map
* the map to use for lookup, not cloned
*/
private MapTransformer(Map<I, O> map) {
super();
iMap = map;
}
/**
* Transforms the input to result by looking it up in a <code>Map</code>.
*
* @param input
* the input object to transform
* @return the transformed result
*/
@Override
public O transform(I input) {
return iMap.get(input);
}
/**
* Gets the map to lookup in.
*
* @return the map
* @since Commons Collections 3.1
*/
public Map<I, O> getMap() {
return iMap;
}
}