44 lines
1.3 KiB
Java
44 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.Comparator;
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/**
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* A comparator based on lexicographical ordering of toString()
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*/
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public class ToStringComparator<T> implements Comparator<T> {
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@SuppressWarnings("rawtypes")
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private static final ToStringComparator INSTANCE = new ToStringComparator();
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private ToStringComparator() {}
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/*
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* @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
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*/
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@Override
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public int compare(T o1, T o2) throws NullPointerException {
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// by convention, null is the least element
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if (o1 == null) {
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return o2 == null ? 0 : -1;
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} else if (o2 == null) {
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return 1;
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}
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return o1.toString().compareTo(o2.toString());
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}
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public static <T> ToStringComparator<T> instance() {
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return INSTANCE;
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}
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}
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