/*******************************************************************************
 * Copyright (c) 2011 - 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.intset;

import java.util.NoSuchElementException;


public class EmptyIntSet implements IntSet {

	public static EmptyIntSet instance = new EmptyIntSet();
	
	@Override
	public boolean contains(int i) {
		return false;
	}

	@Override
	public boolean containsAny(IntSet set) {
		return false;
	}

	@Override
	public IntSet intersection(IntSet that) {
		return this;
	}

	@Override
	public IntSet union(IntSet that) {
		return that;
	}

	@Override
	public boolean isEmpty() {
		return true;
	}

	@Override
	public int size() {
		return 0;
	}

	private static final IntIterator emptyIter = new IntIterator() {

		@Override
		public boolean hasNext() {
			return false;
		}

		@Override
		public int next() {
			throw new NoSuchElementException();
		}
		
	};
	
	@Override
	public IntIterator intIterator() {
		return emptyIter;
	}

	@Override
	public void foreach(IntSetAction action) {

	}

	@Override
	public void foreachExcluding(IntSet X, IntSetAction action) {

	}

	@Override
	public int max() {
		throw new NoSuchElementException();
	}

	@Override
	public boolean sameValue(IntSet that) {
		return that.isEmpty();
	}

	@Override
	public boolean isSubset(IntSet that) {
		return true;
	}
}
