1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/jaxws_classes/com/sun/xml/internal/bind/v2/util/EditDistance.java Tue Mar 06 16:09:35 2012 -0800
1.3 @@ -0,0 +1,125 @@
1.4 +/*
1.5 + * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation. Oracle designates this
1.11 + * particular file as subject to the "Classpath" exception as provided
1.12 + * by Oracle in the LICENSE file that accompanied this code.
1.13 + *
1.14 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.15 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.16 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.17 + * version 2 for more details (a copy is included in the LICENSE file that
1.18 + * accompanied this code).
1.19 + *
1.20 + * You should have received a copy of the GNU General Public License version
1.21 + * 2 along with this work; if not, write to the Free Software Foundation,
1.22 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.23 + *
1.24 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.25 + * or visit www.oracle.com if you need additional information or have any
1.26 + * questions.
1.27 + */
1.28 +
1.29 +package com.sun.xml.internal.bind.v2.util;
1.30 +
1.31 +import java.util.Collection;
1.32 +import java.util.Arrays;
1.33 +
1.34 +/**
1.35 + * Computes the string edit distance.
1.36 + *
1.37 + * <p>
1.38 + * Refer to a computer science text book for the definition
1.39 + * of the "string edit distance".
1.40 + *
1.41 + * @author
1.42 + * Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
1.43 + */
1.44 +public class EditDistance {
1.45 +
1.46 + /**
1.47 + * Computes the edit distance between two strings.
1.48 + *
1.49 + * <p>
1.50 + * The complexity is O(nm) where n=a.length() and m=b.length().
1.51 + */
1.52 + public static int editDistance( String a, String b ) {
1.53 + return new EditDistance(a,b).calc();
1.54 + }
1.55 +
1.56 + /**
1.57 + * Finds the string in the <code>group</code> closest to
1.58 + * <code>key</code> and returns it.
1.59 + *
1.60 + * @return null if group.length==0.
1.61 + */
1.62 + public static String findNearest( String key, String[] group ) {
1.63 + return findNearest(key, Arrays.asList(group));
1.64 + }
1.65 +
1.66 + /**
1.67 + * Finds the string in the <code>group</code> closest to
1.68 + * <code>key</code> and returns it.
1.69 + *
1.70 + * @return null if group.length==0.
1.71 + */
1.72 + public static String findNearest( String key, Collection<String> group ) {
1.73 + int c = Integer.MAX_VALUE;
1.74 + String r = null;
1.75 +
1.76 + for (String s : group) {
1.77 + int ed = editDistance(key,s);
1.78 + if( c>ed ) {
1.79 + c = ed;
1.80 + r = s;
1.81 + }
1.82 + }
1.83 + return r;
1.84 + }
1.85 +
1.86 + /** cost vector. */
1.87 + private int[] cost;
1.88 + /** back buffer. */
1.89 + private int[] back;
1.90 +
1.91 + /** Two strings to be compared. */
1.92 + private final String a,b;
1.93 +
1.94 + private EditDistance( String a, String b ) {
1.95 + this.a=a;
1.96 + this.b=b;
1.97 + cost = new int[a.length()+1];
1.98 + back = new int[a.length()+1]; // back buffer
1.99 +
1.100 + for( int i=0; i<=a.length(); i++ )
1.101 + cost[i] = i;
1.102 + }
1.103 +
1.104 + /**
1.105 + * Swaps two buffers.
1.106 + */
1.107 + private void flip() {
1.108 + int[] t = cost;
1.109 + cost = back;
1.110 + back = t;
1.111 + }
1.112 +
1.113 + private int min(int a,int b,int c) {
1.114 + return Math.min(a,Math.min(b,c));
1.115 + }
1.116 +
1.117 + private int calc() {
1.118 + for( int j=0; j<b.length(); j++ ) {
1.119 + flip();
1.120 + cost[0] = j+1;
1.121 + for( int i=0; i<a.length(); i++ ) {
1.122 + int match = (a.charAt(i)==b.charAt(j))?0:1;
1.123 + cost[i+1] = min( back[i]+match, cost[i]+1, back[i+1]+1 );
1.124 + }
1.125 + }
1.126 + return cost[a.length()];
1.127 + }
1.128 +}
