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21 package oracle.toplink.essentials.internal.ejb.cmp3.xml.parser;
23
24 import org.w3c.dom.Element  ;
25 import org.w3c.dom.Node ;
26 import org.w3c.dom.NodeList ;
27 import org.w3c.dom.Text ;
28
29
33 public class XPathEngine {
34 private static final String ATTRIBUTE = "@";
35 private static final String TEXT = "text()";
36 private static final String ALL_CHILDREN = "child::*";
37 private static final String NAMESPACE_URI = "http://java.sun.com/xml/ns/persistence/orm";
38 private static XPathEngine instance = null;
39
40 private XPathEngine() {
41 super();
42 }
43
44
47 public static XPathEngine getInstance() {
48 if (instance == null) {
49 instance = new XPathEngine();
50 }
51 return instance;
52 }
53
54
63 public Node selectSingleNode(Node contextNode, String [] xPathFragments) {
64 if (contextNode == null) {
65 return null;
66 }
67
68 return selectSingleNode(contextNode, xPathFragments, 0);
69 }
70
71 private Node selectSingleNode(Node contextNode, String [] xPathFragments, int index) {
72 Node resultNode = getSingleNode(contextNode, xPathFragments[index]);
73 if ((resultNode == null) || (xPathFragments.length == (index + 1))) {
74 return resultNode;
75 }
76
77 return selectSingleNode(resultNode, xPathFragments, index + 1);
78 }
79
80
89 public NodeList selectNodes(Node contextNode, String [] xPathFragments) {
90 if (contextNode == null) {
91 return null;
92 }
93
94 return selectNodes(contextNode, xPathFragments, 0);
95 }
96
97 private NodeList selectNodes(Node contextNode, String [] xPathFragments, int index) {
98
99 NodeList resultNodes = getNodes(contextNode, xPathFragments[index]);
100
101 if (xPathFragments.length != index + 1) {
102 Node resultNode;
103 XMLNodeList result = new XMLNodeList();
104 int numberOfResultNodes = resultNodes.getLength();
105 for (int x = 0; x < numberOfResultNodes; x++) {
106 resultNode = resultNodes.item(x);
107 result.addAll(selectNodes(resultNode, xPathFragments, index + 1));
108 }
109 return result;
110 }
111
112 return resultNodes;
113 }
114
115 private Node getSingleNode(Node contextNode, String xPathFragment) {
116 if (xPathFragment.startsWith(ATTRIBUTE)) {
117 return selectSingleAttribute(contextNode, xPathFragment);
118 } else if (TEXT.equals(xPathFragment)) {
119 return selectSingleText(contextNode);
120 }
121 return selectSingleElement(contextNode, xPathFragment);
122 }
123
124 private NodeList getNodes(Node contextNode, String xPathFragment) {
125 if (xPathFragment.startsWith(ATTRIBUTE)) {
126 return selectAttributeNodes(contextNode, xPathFragment);
127 } else if (TEXT.equals(xPathFragment)) {
128 return selectTextNodes(contextNode);
129 } else if (xPathFragment.equals(ALL_CHILDREN)) {
130 return selectChildElements(contextNode);
131 }
132 return selectElementNodes(contextNode, xPathFragment);
133
134 }
135
136 private Node selectSingleAttribute(Node contextNode, String xPathFragment) {
137 Element contextElement = (Element )contextNode;
138 return contextElement.getAttributeNode(xPathFragment.substring(1));
139 }
140
141 private NodeList selectAttributeNodes(Node contextNode, String xPathFragment) {
142 XMLNodeList xmlNodeList = new XMLNodeList();
143
144 Node child = selectSingleAttribute(contextNode, xPathFragment);
145 if (null != child) {
146 xmlNodeList.add(child);
147 }
148 return xmlNodeList;
149 }
150
151 private Node selectSingleElement(Node contextNode, String xPathFragment) {
152 Node child = contextNode.getFirstChild();
153 while (null != child) {
154 if ((child.getNodeType() == Node.ELEMENT_NODE) && sameName(child, xPathFragment) && sameNamespaceURI(child, NAMESPACE_URI)) {
155 return child;
156 }
157
158 child = child.getNextSibling();
159 }
160 return null;
161 }
162
163 private NodeList selectChildElements(Node contextNode) {
164 XMLNodeList xmlNodeList = new XMLNodeList();
165 Node child = contextNode.getFirstChild();
166
167 while (child != null) {
168 if (child.getNodeType() == Node.ELEMENT_NODE) {
169 xmlNodeList.add(child);
170 }
171 child = child.getNextSibling();
172 }
173
174 return xmlNodeList;
175 }
176
177 private NodeList selectElementNodes(Node contextNode, String xPathFragment) {
178 XMLNodeList xmlNodeList = new XMLNodeList();
179 Node child = contextNode.getFirstChild();
180
181 while (null != child) {
182 if ((child.getNodeType() == Node.ELEMENT_NODE) && sameName(child, xPathFragment) && sameNamespaceURI(child, NAMESPACE_URI)) {
183 xmlNodeList.add(child);
184 }
185
186 child = child.getNextSibling();
187 }
188
189 return xmlNodeList;
190 }
191
192 private Node selectSingleText(Node contextNode) {
193 NodeList childrenNodes = contextNode.getChildNodes();
194
195 if (childrenNodes.getLength() == 0) {
196 return null;
197 }
198
199 if (childrenNodes.getLength() == 1) {
200 Node child = childrenNodes.item(0);
201 if (child.getNodeType() == Node.TEXT_NODE) {
202 return child;
203 }
204 return null;
205 }
206
207 String returnVal = null;
208 for (int i = 0; i < childrenNodes.getLength(); i++) {
209 Node next = childrenNodes.item(i);
210 if (next.getNodeType() == Node.TEXT_NODE) {
211 String val = ((Text )next).getNodeValue();
212 if (val != null) {
213 if (returnVal == null) {
214 returnVal = new String ();
215 }
216 returnVal += val;
217 }
218 }
219 }
220
221 if (returnVal != null) {
224 return contextNode.getOwnerDocument().createTextNode(returnVal);
225 }
226 return null;
227 }
228
229 private NodeList selectTextNodes(Node contextNode) {
230 Node n = selectSingleText(contextNode);
231
232 XMLNodeList xmlNodeList = new XMLNodeList();
233 if (n != null) {
234 xmlNodeList.add(n);
235 }
236 return xmlNodeList;
237 }
238
239 private boolean sameNamespaceURI(Node node, String namespaceURI) {
240 String nodeNamespaceURI = node.getNamespaceURI();
242 if (nodeNamespaceURI == namespaceURI) {
243 return true;
244 }
245
246 if ((nodeNamespaceURI == null) && namespaceURI.equals("")) {
247 return true;
248 }
249
250 if ((namespaceURI == null) && nodeNamespaceURI.equals("")) {
251 return true;
252 }
253
254 return (null != nodeNamespaceURI) && nodeNamespaceURI.equals(namespaceURI);
256 }
257
258 private boolean sameName(Node node, String name) {
259 return name.equals(node.getLocalName()) || name.equals(node.getNodeName());
260 }
261 }
262 |
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