| 1 | /* This file is part of the project "Hilbert II" - http://www.qedeq.org |
| 2 | * |
| 3 | * Copyright 2000-2014, Michael Meyling <mime@qedeq.org>. |
| 4 | * |
| 5 | * "Hilbert II" is free software; you can redistribute |
| 6 | * it and/or modify it under the terms of the GNU General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | */ |
| 15 | |
| 16 | package org.qedeq.kernel.xml.tracker; |
| 17 | |
| 18 | import java.util.ArrayList; |
| 19 | import java.util.List; |
| 20 | import java.util.StringTokenizer; |
| 21 | |
| 22 | import org.qedeq.base.utility.EqualsUtility; |
| 23 | |
| 24 | |
| 25 | /** |
| 26 | * Simple XPath like description of a location in an XML file. |
| 27 | * |
| 28 | * @author Michael Meyling |
| 29 | */ |
| 30 | public class SimpleXPath { |
| 31 | |
| 32 | /** List with element names. */ |
| 33 | private final List elements; |
| 34 | |
| 35 | /** List with element occurrence numbers. */ |
| 36 | private final List numbers; |
| 37 | |
| 38 | /** Attribute of element. */ |
| 39 | private String attribute; |
| 40 | |
| 41 | /** |
| 42 | * Constructor with simple XPath string as parameter. |
| 43 | * This is not the standard XPath definition but it is similar to a subset of |
| 44 | * the abbreviation XPath notation. |
| 45 | * <p> |
| 46 | * <code>/element1/element2[3]@attribute</code> is an example for such |
| 47 | * a notation. This selects from the first occurrence of <code>element1</code> |
| 48 | * and from the third occurrence of subnode <code>element2</code> the attribute |
| 49 | * <code>attribute</code>. The attribute is optional. It is always exactly one node or |
| 50 | * the attribute of one node specified. |
| 51 | * <p> |
| 52 | * The general syntax could be described as follows: |
| 53 | * {"/"<em>element</em>"["<em>index</em>"]"}+ |
| 54 | * ["@"<em>attribute</em>] |
| 55 | * |
| 56 | * |
| 57 | * @param xpath String with the syntax as described above. If the syntax is violated |
| 58 | * RuntimeExceptions may occur. |
| 59 | */ |
| 60 | public SimpleXPath(final String xpath) { |
| 61 | elements = new ArrayList(); |
| 62 | numbers = new ArrayList(); |
| 63 | attribute = null; |
| 64 | init(xpath); |
| 65 | } |
| 66 | |
| 67 | /** |
| 68 | * Empty constructor. |
| 69 | */ |
| 70 | public SimpleXPath() { |
| 71 | elements = new ArrayList(); |
| 72 | numbers = new ArrayList(); |
| 73 | attribute = null; |
| 74 | } |
| 75 | |
| 76 | /** |
| 77 | * Copy constructor. |
| 78 | * |
| 79 | * @param original XPath to copy. |
| 80 | */ |
| 81 | public SimpleXPath(final SimpleXPath original) { |
| 82 | elements = new ArrayList(); |
| 83 | numbers = new ArrayList(); |
| 84 | attribute = null; |
| 85 | init(original.toString()); |
| 86 | } |
| 87 | |
| 88 | /** |
| 89 | * Initialize all object attributes according to XPath parameter. |
| 90 | * |
| 91 | * @see SimpleXPath#SimpleXPath(String) |
| 92 | * |
| 93 | * @param xpath String with the syntax as described above. If the syntax is violated |
| 94 | * RuntimeExceptions may occur. |
| 95 | */ |
| 96 | private void init(final String xpath) { |
| 97 | if (xpath == null) { |
| 98 | throw new NullPointerException(); |
| 99 | } |
| 100 | if (xpath.length() <= 0) { |
| 101 | throw new RuntimeException("XPath must not be empty"); |
| 102 | } |
| 103 | if (xpath.charAt(0) != '/') { |
| 104 | throw new RuntimeException("XPath must start with '/': " + xpath); |
| 105 | } |
| 106 | if (xpath.indexOf("//") >= 0) { |
| 107 | throw new RuntimeException("empty tag not permitted: " + xpath); |
| 108 | } |
| 109 | if (xpath.endsWith("/")) { |
| 110 | throw new RuntimeException("XPath must not end with '/': " + xpath); |
| 111 | } |
| 112 | final StringTokenizer tokenizer = new StringTokenizer(xpath, "/"); |
| 113 | while (tokenizer.hasMoreTokens()) { |
| 114 | String token = tokenizer.nextToken(); |
| 115 | if (!tokenizer.hasMoreTokens() && token.indexOf('@') >= 0) { |
| 116 | attribute = token.substring(token.indexOf('@') + 1); |
| 117 | if (attribute.length() <= 0) { |
| 118 | throw new RuntimeException("empty attribute not permitted: " + xpath); |
| 119 | } |
| 120 | token = token.substring(0, token.indexOf('@')); |
| 121 | } |
| 122 | if (token.indexOf('[') < 0) { |
| 123 | elements.add(token); |
| 124 | numbers.add(new Integer(1)); |
| 125 | } else { |
| 126 | final StringTokenizer getnu = new StringTokenizer(token, "[]"); |
| 127 | elements.add(getnu.nextToken()); |
| 128 | final Integer i; |
| 129 | try { |
| 130 | i = new Integer(getnu.nextToken()); |
| 131 | } catch (RuntimeException e) { |
| 132 | throw new RuntimeException("not an integer: " + xpath, e); |
| 133 | } |
| 134 | if (i.intValue() <= 0) { |
| 135 | throw new RuntimeException("integer must be greater zero: " + xpath); |
| 136 | } |
| 137 | numbers.add(i); |
| 138 | } |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | /** |
| 143 | * Get number of collected exceptions. |
| 144 | * |
| 145 | * @return Number of collected exceptions. |
| 146 | */ |
| 147 | public final int size() { |
| 148 | return elements.size(); |
| 149 | } |
| 150 | |
| 151 | /** |
| 152 | * Get <code>i</code>-th Element name. |
| 153 | * |
| 154 | * @param i Starts with 0 and must be smaller than {@link #size()}. |
| 155 | * @return Wanted element name. |
| 156 | */ |
| 157 | public final String getElementName(final int i) { |
| 158 | return (String) elements.get(i); |
| 159 | } |
| 160 | |
| 161 | /** |
| 162 | * Get <code>i</code>-th occurrence number. |
| 163 | * |
| 164 | * @param i Starts with 0 and must be smaller than {@link #size()}. |
| 165 | * @return Wanted element occurrence number. |
| 166 | */ |
| 167 | public final int getElementOccurrence(final int i) { |
| 168 | return ((Integer) numbers.get(i)).intValue(); |
| 169 | } |
| 170 | |
| 171 | /** |
| 172 | * Add new element to end of XPath. |
| 173 | * |
| 174 | * @param elementName element to add. |
| 175 | */ |
| 176 | public final void addElement(final String elementName) { |
| 177 | attribute = null; |
| 178 | elements.add(elementName); |
| 179 | numbers.add(new Integer(1)); |
| 180 | } |
| 181 | |
| 182 | /** |
| 183 | * Add new element to end of XPath. |
| 184 | * |
| 185 | * @param elementName element to add. |
| 186 | * @param occurrence Occurrence number of element. Starts with 1. |
| 187 | */ |
| 188 | public final void addElement(final String elementName, final int occurrence) { |
| 189 | attribute = null; |
| 190 | elements.add(elementName); |
| 191 | numbers.add(new Integer(occurrence)); |
| 192 | } |
| 193 | |
| 194 | /** |
| 195 | * Get last XPath element name. |
| 196 | * |
| 197 | * @return Last element name. Could be <code>null</code> if no elements exist. |
| 198 | */ |
| 199 | public final String getLastElement() { |
| 200 | int size = elements.size(); |
| 201 | if (size <= 0) { |
| 202 | return null; |
| 203 | } |
| 204 | return (String) elements.get(size - 1); |
| 205 | } |
| 206 | |
| 207 | /** |
| 208 | * Get XPath element name before last. |
| 209 | * |
| 210 | * @return Before last element name. Could be <code>null</code> if no more than one element |
| 211 | * exist. |
| 212 | */ |
| 213 | public final String getBeforeLastElement() { |
| 214 | int size = elements.size(); |
| 215 | if (size <= 1) { |
| 216 | return null; |
| 217 | } |
| 218 | return (String) elements.get(size - 2); |
| 219 | } |
| 220 | |
| 221 | /** |
| 222 | * Delete last XPath element if any. |
| 223 | */ |
| 224 | public void deleteLastElement() { |
| 225 | int size = elements.size(); |
| 226 | if (size > 0) { |
| 227 | elements.remove(size - 1); |
| 228 | numbers.remove(size - 1); |
| 229 | attribute = null; |
| 230 | } |
| 231 | } |
| 232 | |
| 233 | /** |
| 234 | * Set attribute. |
| 235 | * |
| 236 | * @param attribute Attribute, maybe <code>null</code>. |
| 237 | */ |
| 238 | public final void setAttribute(final String attribute) { |
| 239 | this.attribute = attribute; |
| 240 | } |
| 241 | |
| 242 | /** |
| 243 | * Get attribute. |
| 244 | * |
| 245 | * @return Attribute, maybe <code>null</code>. |
| 246 | */ |
| 247 | public final String getAttribute() { |
| 248 | return attribute; |
| 249 | } |
| 250 | |
| 251 | |
| 252 | public final boolean equals(final Object obj) { |
| 253 | if (!(obj instanceof SimpleXPath)) { |
| 254 | return false; |
| 255 | } |
| 256 | final SimpleXPath other = (SimpleXPath) obj; |
| 257 | if (!EqualsUtility.equals(this.getAttribute(), other.getAttribute())) { |
| 258 | return false; |
| 259 | } |
| 260 | return equalsElements(other); |
| 261 | } |
| 262 | |
| 263 | /** |
| 264 | * Are the elements and occurrences of this and another element equal? No special treatment |
| 265 | * of "*" elements. |
| 266 | * |
| 267 | * @param other Compare with this object. |
| 268 | * @return Are the elements of this and the parameter object equal? |
| 269 | */ |
| 270 | public final boolean equalsElements(final SimpleXPath other) { |
| 271 | final int size = this.size(); |
| 272 | if (size != other.size()) { |
| 273 | return false; |
| 274 | } |
| 275 | |
| 276 | for (int i = 0; i < size; i++) { |
| 277 | if (!EqualsUtility.equals(this.getElementName(i), other.getElementName(i))) { |
| 278 | return false; |
| 279 | } |
| 280 | if (getElementOccurrence(i) != other.getElementOccurrence(i)) { |
| 281 | return false; |
| 282 | } |
| 283 | } |
| 284 | return true; |
| 285 | } |
| 286 | |
| 287 | /** |
| 288 | * Match the elements and occurrences of this finder object and current elements? |
| 289 | * This object may contain "*" elements. |
| 290 | * |
| 291 | * @param current Compare with this current elements. These elements should not |
| 292 | * contain "*" elements. |
| 293 | * @param currentSummary Contains only "*" elements. This parameter must be identify the same |
| 294 | * XPath as <code>current</code> |
| 295 | * @return Match the elements of this finder object and the parameter objects? |
| 296 | */ |
| 297 | public final boolean matchesElements(final SimpleXPath current, |
| 298 | final SimpleXPath currentSummary) { |
| 299 | final int size = current.size(); |
| 300 | if (size != size()) { |
| 301 | return false; |
| 302 | } |
| 303 | if (size != currentSummary.size()) { |
| 304 | throw new IllegalArgumentException("summary size doesn't match"); |
| 305 | } |
| 306 | |
| 307 | for (int i = 0; i < size; i++) { |
| 308 | if ("*".equals(getElementName(i))) { |
| 309 | if (getElementOccurrence(i) != currentSummary.getElementOccurrence(i)) { |
| 310 | return false; |
| 311 | } |
| 312 | continue; |
| 313 | } |
| 314 | if (!EqualsUtility.equals(current.getElementName(i), getElementName(i))) { |
| 315 | return false; |
| 316 | } |
| 317 | if (current.getElementOccurrence(i) != getElementOccurrence(i)) { |
| 318 | return false; |
| 319 | } |
| 320 | } |
| 321 | return true; |
| 322 | } |
| 323 | |
| 324 | /** |
| 325 | * Match the elements and occurrences of this finder object and current elements? |
| 326 | * This object may contain "*" elements. Checks only to current.size(). |
| 327 | * |
| 328 | * @param current Compare with this current elements. These elements should not |
| 329 | * contain "*" elements. |
| 330 | * @param currentSummary Contains only "*" elements. This parameter must be identify the same |
| 331 | * XPath as <code>current</code> |
| 332 | * @return Match the elements of this finder object and the parameter objects? |
| 333 | */ |
| 334 | public final boolean matchesElementsBegining(final SimpleXPath current, |
| 335 | final SimpleXPath currentSummary) { |
| 336 | final int size = current.size(); |
| 337 | if (size > size()) { |
| 338 | return false; |
| 339 | } |
| 340 | if (size != currentSummary.size()) { |
| 341 | throw new IllegalArgumentException("summary size doesn't match"); |
| 342 | } |
| 343 | |
| 344 | for (int i = 0; i < size; i++) { |
| 345 | if ("*".equals(getElementName(i))) { |
| 346 | if (getElementOccurrence(i) != currentSummary.getElementOccurrence(i)) { |
| 347 | return false; |
| 348 | } |
| 349 | continue; |
| 350 | } |
| 351 | if (!EqualsUtility.equals(current.getElementName(i), getElementName(i))) { |
| 352 | return false; |
| 353 | } |
| 354 | if (current.getElementOccurrence(i) != getElementOccurrence(i)) { |
| 355 | return false; |
| 356 | } |
| 357 | } |
| 358 | return true; |
| 359 | } |
| 360 | |
| 361 | public final String toString() { |
| 362 | final StringBuffer buffer = new StringBuffer(); |
| 363 | for (int i = 0; i < size(); i++) { |
| 364 | buffer.append("/"); |
| 365 | buffer.append(getElementName(i)); |
| 366 | if (getElementOccurrence(i) != 1) { |
| 367 | buffer.append("["); |
| 368 | buffer.append(getElementOccurrence(i)); |
| 369 | buffer.append("]"); |
| 370 | } |
| 371 | } |
| 372 | if (getAttribute() != null) { |
| 373 | buffer.append("@"); |
| 374 | buffer.append(getAttribute()); |
| 375 | } |
| 376 | return buffer.toString(); |
| 377 | } |
| 378 | |
| 379 | public final int hashCode() { |
| 380 | int code = 0; |
| 381 | if (attribute != null) { |
| 382 | code ^= attribute.hashCode(); |
| 383 | } |
| 384 | for (int i = 0; i < size(); i++) { |
| 385 | code ^= i + 1; |
| 386 | code ^= getElementName(i).hashCode(); |
| 387 | code ^= getElementOccurrence(i); |
| 388 | } |
| 389 | return code; |
| 390 | } |
| 391 | |
| 392 | } |