Showing the changes to java/pkg/java/text/CollationKey.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,145 @@ | ||
| 1 | +/* | |
| 2 | + * Copyright (c) 1997, 2005, Oracle and/or its affiliates. All rights reserved. | |
| 3 | + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 | + * | |
| 5 | + * This code is free software; you can redistribute it and/or modify it | |
| 6 | + * under the terms of the GNU General Public License version 2 only, as | |
| 7 | + * published by the Free Software Foundation. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +/* | |
| 27 | + * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved | |
| 28 | + * (C) Copyright IBM Corp. 1996 - All Rights Reserved | |
| 29 | + * | |
| 30 | + * The original version of this source code and documentation is copyrighted | |
| 31 | + * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These | |
| 32 | + * materials are provided under terms of a License Agreement between Taligent | |
| 33 | + * and Sun. This technology is protected by multiple US and International | |
| 34 | + * patents. This notice and attribution to Taligent may not be removed. | |
| 35 | + * Taligent is a registered trademark of Taligent, Inc. | |
| 36 | + * | |
| 37 | + */ | |
| 38 | + | |
| 39 | +package java.text; | |
| 40 | + | |
| 41 | +/** | |
| 42 | + * A <code>CollationKey</code> represents a <code>String</code> under the | |
| 43 | + * rules of a specific <code>Collator</code> object. Comparing two | |
| 44 | + * <code>CollationKey</code>s returns the relative order of the | |
| 45 | + * <code>String</code>s they represent. Using <code>CollationKey</code>s | |
| 46 | + * to compare <code>String</code>s is generally faster than using | |
| 47 | + * <code>Collator.compare</code>. Thus, when the <code>String</code>s | |
| 48 | + * must be compared multiple times, for example when sorting a list | |
| 49 | + * of <code>String</code>s. It's more efficient to use <code>CollationKey</code>s. | |
| 50 | + * | |
| 51 | + * <p> | |
| 52 | + * You can not create <code>CollationKey</code>s directly. Rather, | |
| 53 | + * generate them by calling <code>Collator.getCollationKey</code>. | |
| 54 | + * You can only compare <code>CollationKey</code>s generated from | |
| 55 | + * the same <code>Collator</code> object. | |
| 56 | + * | |
| 57 | + * <p> | |
| 58 | + * Generating a <code>CollationKey</code> for a <code>String</code> | |
| 59 | + * involves examining the entire <code>String</code> | |
| 60 | + * and converting it to series of bits that can be compared bitwise. This | |
| 61 | + * allows fast comparisons once the keys are generated. The cost of generating | |
| 62 | + * keys is recouped in faster comparisons when <code>String</code>s need | |
| 63 | + * to be compared many times. On the other hand, the result of a comparison | |
| 64 | + * is often determined by the first couple of characters of each <code>String</code>. | |
| 65 | + * <code>Collator.compare</code> examines only as many characters as it needs which | |
| 66 | + * allows it to be faster when doing single comparisons. | |
| 67 | + * <p> | |
| 68 | + * The following example shows how <code>CollationKey</code>s might be used | |
| 69 | + * to sort a list of <code>String</code>s. | |
| 70 | + * <blockquote> | |
| 71 | + * <pre> | |
| 72 | + * // Create an array of CollationKeys for the Strings to be sorted. | |
| 73 | + * Collator myCollator = Collator.getInstance(); | |
| 74 | + * CollationKey[] keys = new CollationKey[3]; | |
| 75 | + * keys[0] = myCollator.getCollationKey("Tom"); | |
| 76 | + * keys[1] = myCollator.getCollationKey("Dick"); | |
| 77 | + * keys[2] = myCollator.getCollationKey("Harry"); | |
| 78 | + * sort( keys ); | |
| 79 | + * <br> | |
| 80 | + * //... | |
| 81 | + * <br> | |
| 82 | + * // Inside body of sort routine, compare keys this way | |
| 83 | + * if( keys[i].compareTo( keys[j] ) > 0 ) | |
| 84 | + * // swap keys[i] and keys[j] | |
| 85 | + * <br> | |
| 86 | + * //... | |
| 87 | + * <br> | |
| 88 | + * // Finally, when we've returned from sort. | |
| 89 | + * System.out.println( keys[0].getSourceString() ); | |
| 90 | + * System.out.println( keys[1].getSourceString() ); | |
| 91 | + * System.out.println( keys[2].getSourceString() ); | |
| 92 | + * </pre> | |
| 93 | + * </blockquote> | |
| 94 | + * | |
| 95 | + * @see Collator | |
| 96 | + * @see RuleBasedCollator | |
| 97 | + * @author Helena Shih | |
| 98 | + */ | |
| 99 | + | |
| 100 | +public abstract class CollationKey implements Comparable<CollationKey> { | |
| 101 | + /** | |
| 102 | + * Compare this CollationKey to the target CollationKey. The collation rules of the | |
| 103 | + * Collator object which created these keys are applied. <strong>Note:</strong> | |
| 104 | + * CollationKeys created by different Collators can not be compared. | |
| 105 | + * @param target target CollationKey | |
| 106 | + * @return Returns an integer value. Value is less than zero if this is less | |
| 107 | + * than target, value is zero if this and target are equal and value is greater than | |
| 108 | + * zero if this is greater than target. | |
| 109 | + * @see java.text.Collator#compare | |
| 110 | + */ | |
| 111 | + abstract public int compareTo(CollationKey target); | |
| 112 | + | |
| 113 | + /** | |
| 114 | + * Returns the String that this CollationKey represents. | |
| 115 | + */ | |
| 116 | + public String getSourceString() { | |
| 117 | + return source; | |
| 118 | + } | |
| 119 | + | |
| 120 | + | |
| 121 | + /** | |
| 122 | + * Converts the CollationKey to a sequence of bits. If two CollationKeys | |
| 123 | + * could be legitimately compared, then one could compare the byte arrays | |
| 124 | + * for each of those keys to obtain the same result. Byte arrays are | |
| 125 | + * organized most significant byte first. | |
| 126 | + */ | |
| 127 | + abstract public byte[] toByteArray(); | |
| 128 | + | |
| 129 | + | |
| 130 | + /** | |
| 131 | + * CollationKey constructor. | |
| 132 | + * | |
| 133 | + * @param source - the source string. | |
| 134 | + * @exception NullPointerException if <code>source</code> is null. | |
| 135 | + * @since 1.6 | |
| 136 | + */ | |
| 137 | + protected CollationKey(String source) { | |
| 138 | + if (source==null){ | |
| 139 | + throw new NullPointerException(); | |
| 140 | + } | |
| 141 | + this.source = source; | |
| 142 | + } | |
| 143 | + | |
| 144 | + final private String source; | |
| 145 | +} | |