com.feilong.lib.collection4.iterators.TransformIterator Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of feilong Show documentation
Show all versions of feilong Show documentation
feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
/*
* 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 com.feilong.lib.collection4.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 implements Iterator{
/** The iterator being used */
private Iterator iterator;
/** The transformer being used */
private Transformer transformer;
//-----------------------------------------------------------------------
/**
* Constructs a new TransformIterator
that will not function
* until the {@link #setIterator(Iterator) setIterator} and
* {@link #setTransformer(Transformer)} methods are invoked.
*/
public TransformIterator(){
super();
}
/**
* Constructs a new TransformIterator
that won't transform
* elements from the given iterator.
*
* @param iterator
* the iterator to use
*/
public TransformIterator(final Iterator iterator){
super();
this.iterator = iterator;
}
/**
* Constructs a new 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 iterator, final Transformer 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 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 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(final 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 O transform(final I source){
return transformer.transform(source);
}
}