- /*
- * 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.collections.functors;
-
- import java.io.Serializable;
- import java.util.Map;
-
- import org.apache.commons.collections.Transformer;
-
- /**
- * Transformer implementation that returns the value held in a specified map
- * using the input parameter as a key.
- *
- * @since Commons Collections 3.0
- * @version $Revision: 1.7 $ $Date: 2004/05/16 11:36:31 $
- *
- * @author Stephen Colebourne
- */
- public final class MapTransformer implements Transformer, Serializable {
-
- /** Serial version UID */
- static final long serialVersionUID = 862391807045468939L;
-
- /** The map of data to lookup in */
- private final Map 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 Transformer getInstance(Map map) {
- if (map == null) {
- return ConstantTransformer.NULL_INSTANCE;
- }
- return new MapTransformer(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 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
- */
- public Object transform(Object input) {
- return iMap.get(input);
- }
-
- /**
- * Gets the map to lookup in.
- *
- * @return the map
- * @since Commons Collections 3.1
- */
- public Map getMap() {
- return iMap;
- }
-
- }