org.apache.commons.collections.iterators.SingletonIterator Maven / Gradle / Ivy
/*
* 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 java.util.NoSuchElementException;
/**
* SingletonIterator is an {@link Iterator} over a single
* object instance.
*
* @since 2.0
* @author James Strachan
* @author Stephen Colebourne
* @version $Revision: 1.2.2.1 $
*/
public class SingletonIterator implements Iterator {
private boolean first = true;
private Object object;
/**
* Constructs a new SingletonIterator.
*
* @param object the single object to return from the iterator
*/
public SingletonIterator(Object object) {
super();
this.object = object;
}
/**
* Is another object available from the iterator.
*
* This returns true if the single object hasn't been returned yet.
*
* @return true if the single object hasn't been returned yet
*/
public boolean hasNext() {
return first;
}
/**
* Get the next object from the iterator.
*
* This returns the single object if it hasn't been returned yet.
*
* @return the single object
* @throws NoSuchElementException if the single object has already
* been returned
*/
public Object next() {
if (!first) {
throw new NoSuchElementException();
}
Object answer = object;
object = null;
first = false;
return answer;
}
/**
* Remove always throws {@link UnsupportedOperationException}.
*
* @throws UnsupportedOperationException always
*/
public void remove() {
throw new UnsupportedOperationException("remove() is not supported by this iterator");
}
}