| /******************************************************************************* |
| * Copyright (c) 2005, 2013 Oracle. All rights reserved. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License 2.0, which accompanies this distribution |
| * and is available at https://www.eclipse.org/legal/epl-2.0/. |
| * |
| * Contributors: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.common.utility.internal.iterator; |
| |
| import java.util.Iterator; |
| import org.eclipse.jpt.common.utility.internal.ObjectTools; |
| import org.eclipse.jpt.common.utility.transformer.Transformer; |
| |
| /** |
| * A <code>TransformationIterator</code> wraps another {@link Iterator} |
| * and transforms its results for client consumption. |
| * Objects of type <code>E1</code> are transformed into objects of type <code>E2</code>; |
| * i.e. the iterator returns objects of type <code>E2</code>. |
| * |
| * @param <E1> input: the type of elements to be transformed |
| * @param <E2> output: the type of elements returned by the iterator |
| * |
| * @see org.eclipse.jpt.common.utility.internal.iterable.IterableTools#transform(Iterable, Transformer) |
| */ |
| public class TransformationIterator<E1, E2> |
| implements Iterator<E2> |
| { |
| private final Iterator<? extends E1> iterator; |
| private final Transformer<? super E1, ? extends E2> transformer; |
| |
| |
| /** |
| * Construct an iterator with the specified nested iterator |
| * and transformer. |
| */ |
| public TransformationIterator(Iterator<? extends E1> iterator, Transformer<? super E1, ? extends E2> transformer) { |
| super(); |
| if ((iterator == null) || (transformer == null)) { |
| throw new NullPointerException(); |
| } |
| this.iterator = iterator; |
| this.transformer = transformer; |
| } |
| |
| public boolean hasNext() { |
| // delegate to the nested iterator |
| return this.iterator.hasNext(); |
| } |
| |
| public E2 next() { |
| // transform the object returned by the nested iterator before returning it |
| return this.transformer.transform(this.iterator.next()); |
| } |
| |
| public void remove() { |
| // delegate to the nested iterator |
| this.iterator.remove(); |
| } |
| |
| @Override |
| public String toString() { |
| return ObjectTools.toString(this, this.iterator); |
| } |
| } |