/*
* 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;
/** A Proxy {@link Iterator Iterator} which uses a {@link Transformer Transformer} instance to
* transform the contents of the {@link Iterator Iterator} into some other form
*
* @since 1.0
* @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
*/
public class TransformIterator extends ProxyIterator {
/** Holds value of property transformer. */
private Transformer transformer;
/**
* Constructs a new <Code>TransformIterator</Code> that will not function
* until the {@link #setIterator(Iterator) setIterator} method is
* invoked.
*/
public TransformIterator() {
}
/**
* 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( 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( iterator );
this.transformer = transformer;
}
// Iterator interface
//-------------------------------------------------------------------------
public Object next() {
return transform( super.next() );
}
// Properties
//-------------------------------------------------------------------------
/** Getter for property transformer.
* @return Value of property transformer.
*/
public Transformer getTransformer() {
return transformer;
}
/** Setter for property transformer.
* @param transformer New value of property transformer.
*/
public void setTransformer(Transformer transformer) {
this.transformer = transformer;
}
// Implementation methods
//-------------------------------------------------------------------------
/**
* 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 ) {
Transformer transformer = getTransformer();
if ( transformer != null ) {
return transformer.transform( source );
}
return source;
}
}