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