| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.collections4.iterators; |
| |
| import java.util.Iterator; |
| |
| import org.apache.commons.collections4.Transformer; |
| |
| /** |
| * Decorates an iterator such that each element returned is transformed. |
| * |
| * @since 1.0 |
| */ |
| public class TransformIterator<I, O> implements Iterator<O> { |
| |
| /** The iterator being used */ |
| private Iterator<? extends I> iterator; |
| /** The transformer being used */ |
| private Transformer<? super I, ? extends O> transformer; |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Constructs a new {@code TransformIterator} that will not function |
| * until the {@link #setIterator(Iterator) setIterator} and |
| * {@link #setTransformer(Transformer)} methods are invoked. |
| */ |
| public TransformIterator() { |
| } |
| |
| /** |
| * Constructs a new {@code TransformIterator} that won't transform |
| * elements from the given iterator. |
| * |
| * @param iterator the iterator to use |
| */ |
| public TransformIterator(final Iterator<? extends I> iterator) { |
| this.iterator = iterator; |
| } |
| |
| /** |
| * Constructs a new {@code TransformIterator} 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(final Iterator<? extends I> iterator, |
| final Transformer<? super I, ? extends O> transformer) { |
| this.iterator = iterator; |
| this.transformer = transformer; |
| } |
| |
| //----------------------------------------------------------------------- |
| @Override |
| 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 |
| */ |
| @Override |
| public O next() { |
| return transform(iterator.next()); |
| } |
| |
| @Override |
| public void remove() { |
| iterator.remove(); |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Gets the iterator this iterator is using. |
| * |
| * @return the iterator. |
| */ |
| public Iterator<? extends I> 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(final Iterator<? extends I> iterator) { |
| this.iterator = iterator; |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Gets the transformer this iterator is using. |
| * |
| * @return the transformer. |
| */ |
| public Transformer<? super I, ? extends O> 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(final Transformer<? super I, ? extends O> 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 O transform(final I source) { |
| return transformer.transform(source); |
| } |
| } |