| 1 | /* |
| 2 | * Copyright 2006-2007 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.springframework.batch.support; |
| 17 | |
| 18 | import java.util.ArrayList; |
| 19 | import java.util.Collections; |
| 20 | import java.util.Comparator; |
| 21 | import java.util.HashMap; |
| 22 | import java.util.List; |
| 23 | import java.util.Map; |
| 24 | |
| 25 | import org.springframework.util.Assert; |
| 26 | |
| 27 | /** |
| 28 | * @author Dave Syer |
| 29 | * @author Dan Garrette |
| 30 | */ |
| 31 | public class PatternMatcher<S> { |
| 32 | |
| 33 | private Map<String, S> map = new HashMap<String, S>(); |
| 34 | private List<String> sorted = new ArrayList<String>(); |
| 35 | |
| 36 | /** |
| 37 | * Initialize a new {@link PatternMatcher} with a map of patterns to values |
| 38 | * @param map a map from String patterns to values |
| 39 | */ |
| 40 | public PatternMatcher(Map<String, S> map) { |
| 41 | super(); |
| 42 | this.map = map; |
| 43 | // Sort keys to start with the most specific |
| 44 | sorted = new ArrayList<String>(map.keySet()); |
| 45 | Collections.sort(sorted, new Comparator<String>() { |
| 46 | @Override |
| 47 | public int compare(String o1, String o2) { |
| 48 | String s1 = o1; // .replace('?', '{'); |
| 49 | String s2 = o2; // .replace('*', '}'); |
| 50 | return s2.compareTo(s1); |
| 51 | } |
| 52 | }); |
| 53 | } |
| 54 | |
| 55 | /** |
| 56 | * Lifted from AntPathMatcher in Spring Core. Tests whether or not a string |
| 57 | * matches against a pattern. The pattern may contain two special |
| 58 | * characters:<br> |
| 59 | * '*' means zero or more characters<br> |
| 60 | * '?' means one and only one character |
| 61 | * |
| 62 | * @param pattern pattern to match against. Must not be <code>null</code>. |
| 63 | * @param str string which must be matched against the pattern. Must not be |
| 64 | * <code>null</code>. |
| 65 | * @return <code>true</code> if the string matches against the pattern, or |
| 66 | * <code>false</code> otherwise. |
| 67 | */ |
| 68 | public static boolean match(String pattern, String str) { |
| 69 | char[] patArr = pattern.toCharArray(); |
| 70 | char[] strArr = str.toCharArray(); |
| 71 | int patIdxStart = 0; |
| 72 | int patIdxEnd = patArr.length - 1; |
| 73 | int strIdxStart = 0; |
| 74 | int strIdxEnd = strArr.length - 1; |
| 75 | char ch; |
| 76 | |
| 77 | boolean containsStar = pattern.contains("*"); |
| 78 | |
| 79 | if (!containsStar) { |
| 80 | // No '*'s, so we make a shortcut |
| 81 | if (patIdxEnd != strIdxEnd) { |
| 82 | return false; // Pattern and string do not have the same size |
| 83 | } |
| 84 | for (int i = 0; i <= patIdxEnd; i++) { |
| 85 | ch = patArr[i]; |
| 86 | if (ch != '?') { |
| 87 | if (ch != strArr[i]) { |
| 88 | return false;// Character mismatch |
| 89 | } |
| 90 | } |
| 91 | } |
| 92 | return true; // String matches against pattern |
| 93 | } |
| 94 | |
| 95 | if (patIdxEnd == 0) { |
| 96 | return true; // Pattern contains only '*', which matches anything |
| 97 | } |
| 98 | |
| 99 | // Process characters before first star |
| 100 | while ((ch = patArr[patIdxStart]) != '*' && strIdxStart <= strIdxEnd) { |
| 101 | if (ch != '?') { |
| 102 | if (ch != strArr[strIdxStart]) { |
| 103 | return false;// Character mismatch |
| 104 | } |
| 105 | } |
| 106 | patIdxStart++; |
| 107 | strIdxStart++; |
| 108 | } |
| 109 | if (strIdxStart > strIdxEnd) { |
| 110 | // All characters in the string are used. Check if only '*'s are |
| 111 | // left in the pattern. If so, we succeeded. Otherwise failure. |
| 112 | for (int i = patIdxStart; i <= patIdxEnd; i++) { |
| 113 | if (patArr[i] != '*') { |
| 114 | return false; |
| 115 | } |
| 116 | } |
| 117 | return true; |
| 118 | } |
| 119 | |
| 120 | // Process characters after last star |
| 121 | while ((ch = patArr[patIdxEnd]) != '*' && strIdxStart <= strIdxEnd) { |
| 122 | if (ch != '?') { |
| 123 | if (ch != strArr[strIdxEnd]) { |
| 124 | return false;// Character mismatch |
| 125 | } |
| 126 | } |
| 127 | patIdxEnd--; |
| 128 | strIdxEnd--; |
| 129 | } |
| 130 | if (strIdxStart > strIdxEnd) { |
| 131 | // All characters in the string are used. Check if only '*'s are |
| 132 | // left in the pattern. If so, we succeeded. Otherwise failure. |
| 133 | for (int i = patIdxStart; i <= patIdxEnd; i++) { |
| 134 | if (patArr[i] != '*') { |
| 135 | return false; |
| 136 | } |
| 137 | } |
| 138 | return true; |
| 139 | } |
| 140 | |
| 141 | // process pattern between stars. padIdxStart and patIdxEnd point |
| 142 | // always to a '*'. |
| 143 | while (patIdxStart != patIdxEnd && strIdxStart <= strIdxEnd) { |
| 144 | int patIdxTmp = -1; |
| 145 | for (int i = patIdxStart + 1; i <= patIdxEnd; i++) { |
| 146 | if (patArr[i] == '*') { |
| 147 | patIdxTmp = i; |
| 148 | break; |
| 149 | } |
| 150 | } |
| 151 | if (patIdxTmp == patIdxStart + 1) { |
| 152 | // Two stars next to each other, skip the first one. |
| 153 | patIdxStart++; |
| 154 | continue; |
| 155 | } |
| 156 | // Find the pattern between padIdxStart & padIdxTmp in str between |
| 157 | // strIdxStart & strIdxEnd |
| 158 | int patLength = (patIdxTmp - patIdxStart - 1); |
| 159 | int strLength = (strIdxEnd - strIdxStart + 1); |
| 160 | int foundIdx = -1; |
| 161 | strLoop: for (int i = 0; i <= strLength - patLength; i++) { |
| 162 | for (int j = 0; j < patLength; j++) { |
| 163 | ch = patArr[patIdxStart + j + 1]; |
| 164 | if (ch != '?') { |
| 165 | if (ch != strArr[strIdxStart + i + j]) { |
| 166 | continue strLoop; |
| 167 | } |
| 168 | } |
| 169 | } |
| 170 | |
| 171 | foundIdx = strIdxStart + i; |
| 172 | break; |
| 173 | } |
| 174 | |
| 175 | if (foundIdx == -1) { |
| 176 | return false; |
| 177 | } |
| 178 | |
| 179 | patIdxStart = patIdxTmp; |
| 180 | strIdxStart = foundIdx + patLength; |
| 181 | } |
| 182 | |
| 183 | // All characters in the string are used. Check if only '*'s are left |
| 184 | // in the pattern. If so, we succeeded. Otherwise failure. |
| 185 | for (int i = patIdxStart; i <= patIdxEnd; i++) { |
| 186 | if (patArr[i] != '*') { |
| 187 | return false; |
| 188 | } |
| 189 | } |
| 190 | |
| 191 | return true; |
| 192 | } |
| 193 | |
| 194 | /** |
| 195 | * <p> |
| 196 | * This method takes a String key and a map from Strings to values of any |
| 197 | * type. During processing, the method will identify the most specific key |
| 198 | * in the map that matches the line. Once the correct is identified, its |
| 199 | * value is returned. Note that if the map contains the wildcard string "*" |
| 200 | * as a key, then it will serve as the "default" case, matching every line |
| 201 | * that does not match anything else. |
| 202 | * |
| 203 | * <p> |
| 204 | * If no matching prefix is found, a {@link IllegalStateException} will be |
| 205 | * thrown. |
| 206 | * |
| 207 | * <p> |
| 208 | * Null keys are not allowed in the map. |
| 209 | * |
| 210 | * @param line An input string |
| 211 | * @return the value whose prefix matches the given line |
| 212 | */ |
| 213 | public S match(String line) { |
| 214 | |
| 215 | S value = null; |
| 216 | Assert.notNull(line, "A non-null key must be provided to match against."); |
| 217 | |
| 218 | for (String key : sorted) { |
| 219 | if (PatternMatcher.match(key, line)) { |
| 220 | value = map.get(key); |
| 221 | break; |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | if (value == null) { |
| 226 | throw new IllegalStateException("Could not find a matching pattern for key=[" + line + "]"); |
| 227 | } |
| 228 | return value; |
| 229 | |
| 230 | } |
| 231 | |
| 232 | } |