- /*
- * Copyright 2003-2004 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.collection;
-
- import java.util.ArrayList;
- import java.util.Collection;
- import java.util.Iterator;
- import java.util.List;
-
- import org.apache.commons.collections.Transformer;
-
- /**
- * Decorates another <code>Collection</code> to transform objects that are added.
- * <p>
- * The add methods are affected by this class.
- * Thus objects must be removed or searched for using their transformed form.
- * For example, if the transformation converts Strings to Integers, you must
- * use the Integer form to remove objects.
- * <p>
- * This class is Serializable from Commons Collections 3.1.
- *
- * @since Commons Collections 3.0
- * @version $Revision: 1.7 $ $Date: 2004/06/03 22:02:13 $
- *
- * @author Stephen Colebourne
- */
- public class TransformedCollection extends AbstractSerializableCollectionDecorator {
-
- /** Serialization version */
- private static final long serialVersionUID = 8692300188161871514L;
-
- /** The transformer to use */
- protected final Transformer transformer;
-
- /**
- * Factory method to create a transforming collection.
- * <p>
- * If there are any elements already in the collection being decorated, they
- * are NOT transformed.
- *
- * @param coll the collection to decorate, must not be null
- * @param transformer the transformer to use for conversion, must not be null
- * @return a new transformed collection
- * @throws IllegalArgumentException if collection or transformer is null
- */
- public static Collection decorate(Collection coll, Transformer transformer) {
- return new TransformedCollection(coll, transformer);
- }
-
- //-----------------------------------------------------------------------
- /**
- * Constructor that wraps (not copies).
- * <p>
- * If there are any elements already in the collection being decorated, they
- * are NOT transformed.
- *
- * @param coll the collection to decorate, must not be null
- * @param transformer the transformer to use for conversion, must not be null
- * @throws IllegalArgumentException if collection or transformer is null
- */
- protected TransformedCollection(Collection coll, Transformer transformer) {
- super(coll);
- if (transformer == null) {
- throw new IllegalArgumentException("Transformer must not be null");
- }
- this.transformer = transformer;
- }
-
- /**
- * Transforms an object.
- * <p>
- * The transformer itself may throw an exception if necessary.
- *
- * @param object the object to transform
- * @return a transformed object
- */
- protected Object transform(Object object) {
- return transformer.transform(object);
- }
-
- /**
- * Transforms a collection.
- * <p>
- * The transformer itself may throw an exception if necessary.
- *
- * @param coll the collection to transform
- * @return a transformed object
- */
- protected Collection transform(Collection coll) {
- List list = new ArrayList(coll.size());
- for (Iterator it = coll.iterator(); it.hasNext(); ) {
- list.add(transform(it.next()));
- }
- return list;
- }
-
- //-----------------------------------------------------------------------
- public boolean add(Object object) {
- object = transform(object);
- return getCollection().add(object);
- }
-
- public boolean addAll(Collection coll) {
- coll = transform(coll);
- return getCollection().addAll(coll);
- }
-
- }