/*******************************************************************************
* Copyright (c) 2002 - 2006 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package com.ibm.wala.util.collections;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* A singleton instance of an empty iterator; this is better than
* Collections.EMPTY_SET.iterator(), which allocates an iterator object;
*/
public final class EmptyIterator<T> implements Iterator<T> {
@SuppressWarnings("rawtypes")
private static final EmptyIterator EMPTY = new EmptyIterator();
@SuppressWarnings("unchecked")
public static <T> EmptyIterator<T> instance() {
return EMPTY;
}
/**
* prevent instantiation
*/
private EmptyIterator() {
}
@Override
public boolean hasNext() {
return false;
}
@Override
public T next() {
throw new NoSuchElementException();
}
@Override
public void remove() throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}
}