| /* |
| * Copyright 1999-2004 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.iterators; |
| |
| import java.util.Iterator; |
| |
| import org.apache.commons.collections.Transformer; |
| |
| /** |
| * Decorates an iterator such that each element returned is transformed. |
| * |
| * @since Commons Collections 1.0 |
| * @version $Revision: 1.1 $ $Date: 2009/05/27 22:16:27 $ |
| * |
| * @author James Strachan |
| * @author Stephen Colebourne |
| */ |
| public class TransformIterator implements Iterator { |
| |
| /** The iterator being used */ |
| private Iterator iterator; |
| /** The transformer being used */ |
| private Transformer transformer; |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Constructs a new <code>TransformIterator</code> that will not function |
| * until the {@link #setIterator(Iterator) setIterator} method is |
| * invoked. |
| */ |
| public TransformIterator() { |
| super(); |
| } |
| |
| /** |
| * Constructs a new <code>TransformIterator</code> that won't transform |
| * elements from the given iterator. |
| * |
| * @param iterator the iterator to use |
| */ |
| public TransformIterator(Iterator iterator) { |
| super(); |
| this.iterator = iterator; |
| } |
| |
| /** |
| * Constructs a new <code>TransformIterator</code> that will use the |
| * given iterator and transformer. If the given transformer is null, |
| * then objects will not be transformed. |
| * |
| * @param iterator the iterator to use |
| * @param transformer the transformer to use |
| */ |
| public TransformIterator(Iterator iterator, Transformer transformer) { |
| super(); |
| this.iterator = iterator; |
| this.transformer = transformer; |
| } |
| |
| //----------------------------------------------------------------------- |
| public boolean hasNext() { |
| return iterator.hasNext(); |
| } |
| |
| /** |
| * Gets the next object from the iteration, transforming it using the |
| * current transformer. If the transformer is null, no transformation |
| * occurs and the object from the iterator is returned directly. |
| * |
| * @return the next object |
| * @throws java.util.NoSuchElementException if there are no more elements |
| */ |
| public Object next() { |
| return transform(iterator.next()); |
| } |
| |
| public void remove() { |
| iterator.remove(); |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Gets the iterator this iterator is using. |
| * |
| * @return the iterator. |
| */ |
| public Iterator getIterator() { |
| return iterator; |
| } |
| |
| /** |
| * Sets the iterator for this iterator to use. |
| * If iteration has started, this effectively resets the iterator. |
| * |
| * @param iterator the iterator to use |
| */ |
| public void setIterator(Iterator iterator) { |
| this.iterator = iterator; |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Gets the transformer this iterator is using. |
| * |
| * @return the transformer. |
| */ |
| public Transformer getTransformer() { |
| return transformer; |
| } |
| |
| /** |
| * Sets the transformer this the iterator to use. |
| * A null transformer is a no-op transformer. |
| * |
| * @param transformer the transformer to use |
| */ |
| public void setTransformer(Transformer transformer) { |
| this.transformer = transformer; |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Transforms the given object using the transformer. |
| * If the transformer is null, the original object is returned as-is. |
| * |
| * @param source the object to transform |
| * @return the transformed object |
| */ |
| protected Object transform(Object source) { |
| if (transformer != null) { |
| return transformer.transform(source); |
| } |
| return source; |
| } |
| } |