1 /* 2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * - Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 11 * - Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * - Neither the name of Oracle nor the names of its 16 * contributors may be used to endorse or promote products derived 17 * from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 20 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * This source code is provided to illustrate the usage of a given feature 34 * or technique and has been deliberately simplified. Additional steps 35 * required for a production-quality application, such as security checks, 36 * input validation and proper error handling, might not be present in 37 * this sample code. 38 */ 39 40 package comparator; 41 42 import java.util.Comparator; 43 44 class AlphaNumericCharArrayComparator implements Comparator<char[]> 45 { 46 final Comparator<Character> charComparator; 47 48 public AlphaNumericCharArrayComparator() { 49 this(Character::compare); 50 } 51 52 public AlphaNumericCharArrayComparator(Comparator<Character> charComparator) { 53 this.charComparator = charComparator; 54 } 55 56 /** 57 * Counts how many consequtive characters in the array {@code o} 58 * are digits, starting from the position {@code from}. 59 */ 60 private int countDigits(char[] o, int from) { 61 for (int i = from; ; ++i) { 62 if (i == o.length || !Character.isDigit(o[i])) { 63 return (i - from); 64 } 65 } 66 } 67 68 @Override 69 public int compare(char[] o1, char[] o2) { 70 final int minLength = Integer.min(o1.length, o2.length); 71 int numStart1 = 0; 72 int index = 0; 73 74 // skip common prefix of the arguments 75 while (index < minLength && 76 charComparator.compare(o1[index], o2[index]) == 0) 77 { 78 if (!Character.isDigit(o1[index++])) { 79 numStart1 = index; 80 } 81 } 82 83 int numCount1 = index - numStart1; 84 if (numCount1 > 0 || 85 (index < minLength && 86 Character.isDigit(o1[index]) && 87 Character.isDigit(o2[index]))) 88 { 89 // first different char is digit 90 int numCount2 = numCount1; 91 int numStart2 = numStart1; 92 93 numCount1 += countDigits(o1, index); 94 numCount2 += countDigits(o2, index); 95 96 int numCountWithZeros1 = numCount1; 97 int numCountWithZeros2 = numCount2; 98 99 while (numCount1 < numCount2) { 100 if (charComparator.compare(o2[numStart2], '0') != 0) { 101 return -1; 102 } 103 numStart2++; 104 numCount2--; 105 } 106 107 while (numCount2 < numCount1) { 108 if (charComparator.compare(o1[numStart1], '0') != 0) { 109 return 1; 110 } 111 numStart1++; 112 numCount1--; 113 } 114 115 // here numCount1 == numCount2; 116 while (numCount1-- > 0) { 117 int res = charComparator.compare(o1[numStart1++], o2[numStart2++]); 118 if (res != 0) { 119 return res; 120 } 121 } 122 123 if (numCountWithZeros1 != numCountWithZeros2) { 124 return (numCountWithZeros1 < numCountWithZeros2) ? -1 : 1; 125 } 126 127 } 128 129 // otherwise, compare literally 130 for (;; ++index) { 131 if (index < o1.length) { 132 if (index < o2.length) { 133 int res = charComparator.compare(o1[index], o2[index]); 134 if (res != 0) { 135 return res; 136 } 137 } else { 138 return 1; 139 } 140 } else { 141 if (index < o2.length) { 142 return -1; 143 } 144 return 0; 145 } 146 } 147 } 148 }