|
1
11 package org.eclipse.help.internal;
12
13 import java.io.StringReader  ;
14 import java.lang.reflect.Array ;
15 import java.util.ArrayList ;
16 import java.util.List ;
17
18 import javax.xml.parsers.DocumentBuilder ;
19 import javax.xml.parsers.DocumentBuilderFactory ;
20 import javax.xml.parsers.ParserConfigurationException ;
21
22 import org.eclipse.core.expressions.EvaluationResult;
23 import org.eclipse.core.expressions.Expression;
24 import org.eclipse.core.expressions.ExpressionConverter;
25 import org.eclipse.core.expressions.ExpressionTagNames;
26 import org.eclipse.core.expressions.IEvaluationContext;
27 import org.eclipse.core.runtime.CoreException;
28 import org.eclipse.help.HelpSystem;
29 import org.eclipse.help.IUAElement;
30 import org.eclipse.help.internal.dynamic.FilterResolver;
31 import org.w3c.dom.Document ;
32 import org.w3c.dom.Element ;
33 import org.w3c.dom.Node ;
34 import org.xml.sax.EntityResolver ;
35 import org.xml.sax.InputSource ;
36 import org.xml.sax.SAXException ;
37
38
41 public class UAElement implements IUAElement {
42
43 private static final String ELEMENT_FILTER = "filter"; private static final String ATTRIBUTE_FILTER = "filter"; private static final String ATTRIBUTE_NAME = "name"; private static final String ATTRIBUTE_VALUE = "value";
48 private static DocumentBuilder builder;
49 private static Document document;
50
51 public Element element;
52 public IUAElement src;
53 public UAElement parent;
54 public UAElement[] children;
56 public UAElement(Element element) {
57 this.element = element;
58 }
59
60 public UAElement(String name) {
61 this.element = getDocument().createElement(name);
62 }
63
64 public UAElement(String name, IUAElement src) {
65 this(name);
66 this.src = src;
67 }
68
69 public void appendChild(UAElement uaElementToAppend) {
70 importElement(uaElementToAppend);
71 element.appendChild(uaElementToAppend.element);
72 uaElementToAppend.parent = this;
73
74 children = null;
76 }
77
78 public void appendChildren(IUAElement[] children) {
79 for (int i=0;i<children.length;i++) {
80 appendChild(children[i] instanceof UAElement ? (UAElement)children[i] : UAElementFactory.newElement(children[i]));
81 }
82 }
83
84 public String getAttribute(String name) {
85 String value = element.getAttribute(name);
86 if (value.length() > 0) {
87 return value;
88 }
89 return null;
90 }
91
92 public IUAElement[] getChildren() {
93 if (children == null) {
94 if (element.hasChildNodes()) {
95 List list = new ArrayList ();
96 Node node = element.getFirstChild();
97 while (node != null) {
98 if (node.getNodeType() == Node.ELEMENT_NODE) {
99 UAElement uaElement = UAElementFactory.newElement((Element)node);
100 uaElement.parent = this;
101 if (uaElement != null) {
102 list.add(uaElement);
103 }
104 }
105 node = node.getNextSibling();
106 }
107 children = (UAElement[])list.toArray(new UAElement[list.size()]);
108 }
109 else {
110 children = new UAElement[0];
111 }
112 }
113 return children;
114 }
115
116 public Object getChildren(Class clazz) {
117 IUAElement[] children = getChildren();
118 if (children.length > 0) {
119 List list = new ArrayList ();
120 for (int i=0;i<children.length;++i) {
121 IUAElement child = children[i];
122 if (clazz.isAssignableFrom(child.getClass())) {
123 list.add(child);
124 }
125 }
126 return list.toArray((Object [])Array.newInstance(clazz, list.size()));
127 }
128 return Array.newInstance(clazz, 0);
129 }
130
131 public String getElementName() {
132 return element.getNodeName();
133 }
134
135 public static Document getDocument() {
136 if (document == null) {
137 if (builder == null) {
138 try {
139 builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
140 builder.setEntityResolver(new EntityResolver () {
141 public InputSource resolveEntity(String publicId, String systemId) throws SAXException {
142 return new InputSource (new StringReader ("")); }
144 });
145 }
146 catch (ParserConfigurationException e) {
147 String msg = "Error creating document builder"; HelpPlugin.logError(msg, e);
149 }
150 }
151 document = builder.newDocument();
152 }
153 return document;
154 }
155
156 public UAElement getParentElement() {
157 return parent;
158 }
159
160 public void insertBefore(UAElement newChild, UAElement refChild) {
161 importElement(newChild);
162 element.insertBefore(newChild.element, refChild.element);
163 newChild.parent = this;
164
165 children = null;
167 }
168
169 public boolean isEnabled(IEvaluationContext context) {
170 if (HelpSystem.isShared()) {
171 return true;
172 }
173 if (src != null) {
174 return src.isEnabled(context);
175 }
176 String filter = getAttribute(ATTRIBUTE_FILTER);
177 if (filter != null) {
178 return isEnabledByFilterAttribute(filter);
179 }
180 Node node = element.getFirstChild();
181 while (node != null) {
182 if (node.getNodeType() == Node.ELEMENT_NODE) {
183 String name = node.getNodeName();
184 if (ExpressionTagNames.ENABLEMENT.equals(name)) {
185 return isEnabledByEnablementElement((Element)node, context);
186 }
187 else if (ELEMENT_FILTER.equals(name)) {
188 if (!isEnabledByFilterElement((Element)node)) {
190 return false;
191 }
192 }
193 }
194 node = node.getNextSibling();
195 }
196 return true;
197 }
198
199 public void removeChild(UAElement elementToRemove) {
200 element.removeChild(elementToRemove.element);
201 elementToRemove.parent = null;
202
203 children = null;
205 }
206
207 public void setAttribute(String name, String value) {
208 element.setAttribute(name, value);
209 }
210
211 private void importElement(UAElement uaElementToImport) {
212 Element elementToImport = uaElementToImport.element;
213 Document ownerDocument = element.getOwnerDocument();
214 if (!ownerDocument.equals(elementToImport.getOwnerDocument())) {
215 elementToImport = (Element)ownerDocument.importNode(elementToImport, true);
216 }
217 uaElementToImport.element = elementToImport;
218 }
219
220 private boolean isEnabledByEnablementElement(Element enablement, IEvaluationContext context) {
221 try {
222 Expression expression = ExpressionConverter.getDefault().perform(enablement);
223 return expression.evaluate(context) == EvaluationResult.TRUE;
224 }
225 catch (CoreException e) {
226
230 return true;
231 }
232 }
233
234 private boolean isEnabledByFilterAttribute(String filter) {
235 return !FilterResolver.getInstance().isFiltered(filter);
236 }
237
238 private boolean isEnabledByFilterElement(Element filter) {
239 String name = filter.getAttribute(ATTRIBUTE_NAME);
240 String value = filter.getAttribute(ATTRIBUTE_VALUE);
241 if (name.length() > 0 && value.length() > 0) {
242 boolean not = false;
243 if (value.startsWith("!")) { not = true;
245 value = value.substring(1);
246 }
247 return !FilterResolver.getInstance().isFiltered(name, value, not);
248 }
249 return true;
251 }
252 }
253 |
Popular Tags |
Java API By Example, From Geeks To Geeks.