|
1
19
20 package org.netbeans.modules.xml.xdm.visitor;
21
22 import java.util.ArrayList  ;
23 import java.util.Collections ;
24 import java.util.HashMap ;
25 import java.util.List ;
26 import java.util.Map ;
27 import java.util.StringTokenizer ;
28 import javax.xml.namespace.NamespaceContext ;
29 import javax.xml.xpath.XPath ;
30 import javax.xml.xpath.XPathConstants ;
31 import javax.xml.xpath.XPathExpressionException ;
32 import javax.xml.xpath.XPathFactory ;
33 import org.netbeans.modules.xml.xdm.nodes.Attribute;
34 import org.netbeans.modules.xml.xdm.nodes.Document;
35 import org.netbeans.modules.xml.xdm.nodes.Element;
36 import org.netbeans.modules.xml.xdm.nodes.Node;
37 import org.w3c.dom.NodeList ;
38
39
44 public class XPathFinder extends ChildVisitor {
45
46
51 public static String getXpath(Document root, Node target) {
52 if (!(target instanceof Element) && !(target instanceof Attribute)) {
53 throw new IllegalArgumentException ("Can only get XPath expression for Element or Attribute");
54 }
55 List <Node> result = new PathFromRootVisitor().findPath(root, target);
56 StringBuffer sb = new StringBuffer (128);
57 Element parent = null;
58 for (int j=result.size()-1; j >= 0; j--) {
59 Node n = result.get(j);
60 boolean isElement = n instanceof Element;
61 boolean isAttribute = n instanceof Attribute;
62 if (! isElement && ! isAttribute) {
63 continue;
64 }
65 sb.append(SEP);
66 int index = isElement ? xpathIndexOf(parent, (Element) n) : -1;
67 String prefix = n.getPrefix();
68 String namespace = n.lookupNamespaceURI(prefix);
69 if (isAttribute) {
70 sb.append(AT);
71 }
72 if (prefix != null) {
73 sb.append(prefix);
74 sb.append(':');
75 }
76 sb.append(n.getLocalName());
77 if (isElement && index > 0) {
78 sb.append(BRACKET0);
79 sb.append(String.valueOf(index));
80 sb.append(BRACKET1);
81 }
82 if (isAttribute) {
83 break;
84 }
85 parent = (Element) n;
86 }
87 return sb.toString();
88 }
89
90
96 public Node findNode(Document root, String xpath) {
97 List <Node> nodes = findNodes(root, xpath);
98 return nodes.size() > 0 ? nodes.get(0) : null;
99 }
100
101
106 public List <Node> findNodes(Document root, String xpathExpression) {
107 if (root == null || root.getDocumentElement() == null) {
108 return Collections.emptyList();
109 }
110
111 init(root, xpathExpression);
112 if (! isReadyForEvaluation()) {
113 return new ArrayList <Node>();
114 }
115
116 XPath xpath = XPathFactory.newInstance().newXPath();
117 xpath.setNamespaceContext(getNamespaceContext());
118 NodeList result = null;
119 try {
120 result = (NodeList ) xpath.evaluate(getFixedUpXpath(), root, XPathConstants.NODESET);
121 } catch (XPathExpressionException e) {
122 throw new RuntimeException (e.getCause().getLocalizedMessage());
123 }
124 assert(result != null);
125 List <Node> ret = new ArrayList <Node>();
126 for (int i=0; i<result.getLength(); i++) {
127 ret.add((Node) result.item(i));
128 }
129 return ret;
130 }
131
132 private static int xpathIndexOf(Node parentNode, Element child) {
134 assert(child != null);
135 if (!(parentNode instanceof Element || parentNode instanceof Document)) {
136 return -1;
137 }
138
139 NodeList children = parentNode.getChildNodes();
140 int index = 0;
141 String namespace = child.getNamespaceURI();
142 String name = child.getLocalName();
143 for (int i = 0; i<children.getLength(); i++) {
144 if (! (children.item(i) instanceof Element)) {
145 continue;
146 }
147 Element n = (Element) children.item(i);
148 if (namespace != null && ! namespace.equals(n.getNamespaceURI()) ||
149 namespace == null && n.getNamespaceURI() != null)
150 {
151 continue;
152 }
153
154 if (name.equals(n.getLocalName())) {
155 index++;
156 }
157
158 if (n.getId() == child.getId()) {
159 return index;
160 }
161 }
162
163 return -1;
164 }
165
166 private void init(Document root, String xpath) {
167 currentParent = root;
168 initTokens(xpath);
169 ((Element)root.getDocumentElement()).accept(this);
170 }
171
172 private void initTokens(String xpath) {
173 tokens = new ArrayList <XPathSegment>();
174 StringTokenizer tokenizer = new StringTokenizer (xpath, SEP);
175 while (tokenizer.hasMoreTokens()) {
176 String token = tokenizer.nextToken();
177 tokens.add(new XPathSegment(token));
178 }
179 }
180
181 private static class XPathSegment {
182 private final String token;
183 private String prefix;
184 private String localPart;
185 int index = -1;
186 private String remaining;
187 private boolean isAttribute;
188 private boolean hasConditions;
189
190 XPathSegment(String token) {
191 this.token = token;
192 parse();
193 }
194
195 private void parse() {
196 StringTokenizer tokenizer = new StringTokenizer (token, ":[");
197 List <String > parts = new ArrayList <String >();
198 while (tokenizer.hasMoreTokens()) {
199 String t = tokenizer.nextToken();
200 parts.add(t);
201 }
202 if (parts.size() == 1) {
203 prefix = "";
204 localPart = parts.get(0);
205 remaining = "";
206 } else if (parts.size() == 3) {
207 prefix = parts.get(0);
208 localPart = parts.get(1);
209 remaining = parts.get(2);
210 } else if (parts.size() == 2) {
211 String part0 = parts.get(0);
212 if (token.charAt(part0.length()) == ':') {
213 prefix = part0;
214 localPart = parts.get(1);
215 remaining = "";
216 } else {
217 localPart = parts.get(0);
218 remaining = parts.get(1);
219 prefix = "";
220 }
221 }
222 if (prefix != null && prefix.startsWith(AT)) {
223 isAttribute = true;
224 prefix = prefix.substring(1);
225 } else if (localPart.startsWith(AT)) {
226 isAttribute = true;
227 localPart = localPart.substring(1);
228 }
229 if (! remaining.equals("")) {
230 String indexString = remaining.substring(0, remaining.length()-1);
231 try {
232 index = Integer.parseInt(indexString);
233 } catch (NumberFormatException ex) {
234 hasConditions = true;
235 }
236 remaining = BRACKET0 + remaining;
237 }
238 }
239
240 public boolean checkTypeAndName(Node e, Node parent) {
241 if (e instanceof Element) {
242 if (isAttribute()) return false;
243 if (hasPlainIndex() && getIndex() != xpathIndexOf(parent, (Element) e)) {
244 return false;
245 }
246 } else if (e instanceof Attribute) {
247 if (! isAttribute()) return false;
248 } else {
249 return false;
250 }
251 if (! e.getLocalName().equals(getLocalPart())){
252 return false;
253 }
254 return true;
255 }
256
257 public void addToXpath(StringBuffer xpath, String prefix) {
258 xpath.append(SEP);
259 if (isAttribute()) {
260 xpath.append(AT);
261 }
262 xpath.append(prefix);
263 xpath.append(COLON);
264 xpath.append(localPart);
265 if (hasConditions() && !prefix.startsWith(XPNS)) {
266 String prefixing = AT + prefix + COLON;
267 xpath.append(remaining.replaceAll(AT, prefixing));
269 } else {
270 xpath.append(remaining);
271 }
272 }
273
274 public void addToXpath(StringBuffer xpath) {
275 xpath.append(SEP);
276 xpath.append(token);
277 }
278
279 public String getPrefix() { return prefix; }
280 public String getLocalPart() { return localPart; }
281 public boolean hasPlainIndex() { return index > -1; }
282 public boolean hasConditions() { return hasConditions; }
283 public int getIndex() { return index; }
284 public String getRemaining() { return remaining; }
285 public String getToken() { return token; }
286 public boolean isAttribute() { return isAttribute; }
287 public String toString() { return token; }
288 }
289
290 protected void visitNode(Node e) {
291 if (tokens.size() == 0) {
292 done = true;
293 return;
294 }
295
296 XPathSegment segment = tokens.get(0);
297 if (! segment.checkTypeAndName(e, currentParent)) {
298 return; }
300
301 String currentNamespace = e.getNamespaceURI();
302 if (currentNamespace != null) {
303 String prefix = segment.getPrefix();
304 if (prefix.length() > 0) {
305 String namespace = e.lookupNamespaceURI(prefix);
306 if (namespace == null) {
307 namespace = namespaces.get(prefix);
308 } if (namespace != null && ! currentNamespace.equals(namespace)) {
309 return; }
311 segment.addToXpath(fixedUpXpath);
312 } else {
313 prefix = prefixes.get(currentNamespace);
315 if (prefix == null) {
316 prefix = XPNS + String.valueOf(countNamespaceSuffix++);
317 }
318 segment.addToXpath(fixedUpXpath, prefix);
319 }
320 prefixes.put(currentNamespace, prefix);
322 namespaces.put(prefix, currentNamespace);
323 } else {
324 segment.addToXpath(fixedUpXpath);
325 }
326
327 tokens.remove(0);
328 currentParent = e;
329 super.visitNode(e);
330 }
331
332 public boolean isReadyForEvaluation() {
333 return done;
334 }
335 public NamespaceContext getNamespaceContext() {
336 return new HashNamespaceResolver(namespaces, prefixes);
337 }
338 private String getFixedUpXpath() {
339 return fixedUpXpath.toString();
340 }
341
342 private boolean done = false;
343 private Node currentParent = null;
344 private Map <String , String > namespaces = new HashMap <String ,String >();
345 private Map <String , String > prefixes = new HashMap <String ,String >();
346 private List <XPathSegment> tokens;
347 private StringBuffer fixedUpXpath = new StringBuffer ();
348
349 public static final String SEP = "/"; public static final String AT = "@"; public static final String COLON = ":"; public static final String BRACKET0 = "["; public static final String BRACKET1 = "]"; public static final String XPNS = "xpns"; private int countNamespaceSuffix = 0;
356 }
357 |
Popular Tags |
Java API By Example, From Geeks To Geeks.