001/* 002 * Copyright 2002-2012 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.util.comparator; 018 019import java.io.Serializable; 020import java.util.Comparator; 021 022/** 023 * A Comparator for Boolean objects that can sort either true or false first. 024 * 025 * @author Keith Donald 026 * @since 1.2.2 027 */ 028@SuppressWarnings("serial") 029public final class BooleanComparator implements Comparator<Boolean>, Serializable { 030 031 /** 032 * A shared default instance of this comparator, treating true lower 033 * than false. 034 */ 035 public static final BooleanComparator TRUE_LOW = new BooleanComparator(true); 036 037 /** 038 * A shared default instance of this comparator, treating true higher 039 * than false. 040 */ 041 public static final BooleanComparator TRUE_HIGH = new BooleanComparator(false); 042 043 044 private final boolean trueLow; 045 046 047 /** 048 * Create a BooleanComparator that sorts boolean values based on 049 * the provided flag. 050 * <p>Alternatively, you can use the default shared instances: 051 * {@code BooleanComparator.TRUE_LOW} and 052 * {@code BooleanComparator.TRUE_HIGH}. 053 * @param trueLow whether to treat true as lower or higher than false 054 * @see #TRUE_LOW 055 * @see #TRUE_HIGH 056 */ 057 public BooleanComparator(boolean trueLow) { 058 this.trueLow = trueLow; 059 } 060 061 062 @Override 063 public int compare(Boolean v1, Boolean v2) { 064 return (v1 ^ v2) ? ((v1 ^ this.trueLow) ? 1 : -1) : 0; 065 } 066 067 @Override 068 public boolean equals(Object obj) { 069 if (this == obj) { 070 return true; 071 } 072 if (!(obj instanceof BooleanComparator)) { 073 return false; 074 } 075 return (this.trueLow == ((BooleanComparator) obj).trueLow); 076 } 077 078 @Override 079 public int hashCode() { 080 return (this.trueLow ? -1 : 1) * getClass().hashCode(); 081 } 082 083 @Override 084 public String toString() { 085 return "BooleanComparator: " + (this.trueLow ? "true low" : "true high"); 086 } 087 088}