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	/*
	* 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</code> that will not function
	* until the {@link #setIterator(Iterator) setIterator} and
	* {@link #setTransformer(Transformer)} methods are 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(final Iterator<? extends I> 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(final Iterator<? extends I> iterator,
	final Transformer<? super I, ? extends O> transformer) {
	super();
	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);
	}
	}

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