TocFragmentServlet


1   /*******************************************************************************
2    * Copyright (c) 2006, 2007 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  package org.eclipse.help.internal.webapp.servlet;
12  
13  import java.io.IOException  ;
14  import java.util.Locale  ;
15  import java.util.Map  ;
16  import java.util.WeakHashMap  ;
17  
18  import javax.servlet.ServletException  ;
19  import javax.servlet.http.HttpServlet  ;
20  import javax.servlet.http.HttpServletRequest  ;
21  import javax.servlet.http.HttpServletResponse  ;
22  
23  import org.eclipse.help.IToc;
24  import org.eclipse.help.ITopic;
25  import org.eclipse.help.internal.webapp.WebappResources;
26  import org.eclipse.help.internal.webapp.data.EnabledTopicUtils;
27  import org.eclipse.help.internal.webapp.data.TocData;
28  import org.eclipse.help.internal.webapp.data.UrlUtil;
29  
30  /*
31   * Creates xml representing selected parts of one or more TOCs  depending on the parameters
32   * With no parameters the head of each toc is included
33   * With parameter "href" the node and all its ancestors and siblings is included, corresponds to show in toc 
34   * With parameter "toc" and optionally "path" the node, its ancestors and children are included
35   */
36  public class TocFragmentServlet extends HttpServlet   {
37      
38      private static final long serialVersionUID = 1L;
39      private static Map   locale2Response = new WeakHashMap  ();
40  
41      protected void doGet(HttpServletRequest   req, HttpServletResponse   resp)
42              throws ServletException  , IOException   {
43          String   locale = UrlUtil.getLocale(req, resp);
44          req.setCharacterEncoding("UTF-8"); //$NON-NLS-1$
45          resp.setContentType("application/xml; charset=UTF-8"); //$NON-NLS-1$
46          resp.setHeader("Cache-Control","no-cache");   //$NON-NLS-1$//$NON-NLS-2$
47          resp.setHeader("Pragma","no-cache");  //$NON-NLS-1$ //$NON-NLS-2$
48          resp.setDateHeader ("Expires", 0);   //$NON-NLS-1$
49          TocData data = new TocData(this.getServletContext(), req, resp);    
50          Serializer serializer = new Serializer(data, req.getLocale());
51          String   response = serializer.generateTreeXml(); 
52          locale2Response.put(locale, response);
53          resp.getWriter().write(response);
54      }
55      
56      /*
57       * Class which creates the xml file based upon the request parameters
58       */
59      private class Serializer {
60          
61          private TocData tocData;
62          private StringBuffer   buf;
63          private int requestKind;
64          private Locale   locale;
65          private static final int REQUEST_SHOW_IN_TOC = 1;      // Show an element based on its href
66          private static final int REQUEST_SHOW_TOCS = 2;        // Show all the tocs but not their children
67          private static final int REQUEST_SHOW_CHILDREN = 3;    // Show the children of a node
68  
69          public Serializer(TocData data, Locale   locale) {
70              tocData = data;
71              buf = new StringBuffer  ();
72              this.locale = locale;
73              if (tocData.getTopicHref() != null) {
74                  requestKind = REQUEST_SHOW_IN_TOC;
75              } else if (tocData.getSelectedToc() == -1) {
76                  requestKind = REQUEST_SHOW_TOCS;
77              } else {
78                  requestKind = REQUEST_SHOW_CHILDREN;
79              }
80          }
81              
82          public String   generateTreeXml() {
83              buf.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"); //$NON-NLS-1$
84              buf.append("<tree_data>\n"); //$NON-NLS-1$
85              
86  
87              if (tocData.isRemoteHelpError()) {
88                  addError(WebappResources.getString("remoteHelpErrorMessage", locale)); //$NON-NLS-1$            
89              }
90                      
91              // Return an error for show in toc if topic was not found in toc
92              if (requestKind == REQUEST_SHOW_IN_TOC && tocData.getTopicPath() == null) {
93                  addError(WebappResources.getString("CannotSync", locale)); //$NON-NLS-1$
94              } else {
95                  serializeTocs();
96              }
97              buf.append("</tree_data>\n"); //$NON-NLS-1$
98              return buf.toString();
99          }
100 
101         private void addError(String   message) {
102             buf.append("<error>"); //$NON-NLS-1$
103             buf.append(XMLGenerator.xmlEscape(message));
104             buf.append("</error>"); //$NON-NLS-1$           
105         }
106 
107         private void serializeTocs() {
108             ITopic[] topicPath = tocData.getTopicPath();
109     
110             int selectedToc = tocData.getSelectedToc();
111             // Iterate over all tocs - if there is a selected toc only generate that
112             // toc, otherwise generate the root of every toc.
113             for (int toc=0; toc< tocData.getTocCount(); toc++) {
114                 boolean shouldLoad = requestKind == REQUEST_SHOW_TOCS || toc == selectedToc;
115                 if(!tocData.isEnabled(toc)){
116                     shouldLoad = false;
117                 } 
118                 if (shouldLoad) {
119                     boolean isSelected = false; // Should this node be selected in the tree
120                     if (requestKind == REQUEST_SHOW_TOCS) {
121                         isSelected = toc == 0;
122                     } else if (requestKind == REQUEST_SHOW_CHILDREN) {
123                         isSelected = tocData.getRootPath() == null;
124                     }
125                     serializeToc(tocData.getTocs()[toc], toc, topicPath, isSelected);
126                 }
127             }
128         }
129     
130         private void serializeToc(IToc toc, int tocIndex, ITopic[] topicPath, boolean isSelected) {
131             ITopic[] topics = EnabledTopicUtils.getEnabled(toc.getTopics());
132             if (topics.length <= 0) {
133                 // do not generate toc when there are no leaf topics
134                 return;
135             }
136             
137             if (requestKind == REQUEST_SHOW_CHILDREN) {
138                 topicPath = getTopicPathFromRootPath(toc);
139             }
140             
141             buf.append("<node"); //$NON-NLS-1$
142             if (toc.getLabel() != null) { 
143                 buf.append('\n' + "      title=\"" + XMLGenerator.xmlEscape(toc.getLabel()) + '"'); //$NON-NLS-1$
144             }
145             buf.append('\n' + "      id=\"" + XMLGenerator.xmlEscape(toc.getHref()) + "\""); //$NON-NLS-1$ //$NON-NLS-2$
146 
147             String   href = toc.getTopic(null).getHref();
148             if (href == null) {
149                 href = "/../nav/" + tocIndex; //$NON-NLS-1$
150             }
151             buf.append('\n' + "      HREF=\"" + XMLGenerator.xmlEscape(UrlUtil.getHelpURL(href)) + "\""); //$NON-NLS-1$ //$NON-NLS-2$
152 
153             buf.append('\n' + "      image=\"toc_closed\""); //$NON-NLS-1$
154                 
155             boolean serializeChildren = true;
156             if (requestKind == REQUEST_SHOW_TOCS) {
157                 serializeChildren = false;
158             }
159             if (requestKind == REQUEST_SHOW_IN_TOC && topicPath.length == 0) {
160                 serializeChildren = false;
161                 buf.append('\n' + "      is_selected=\"true\"" ); //$NON-NLS-1$
162                 buf.append('\n' + "      is_highlighted=\"true\"" ); //$NON-NLS-1$  
163             }
164             buf.append(">\n"); //$NON-NLS-1$
165             if (serializeChildren) { 
166                 serializeChildTopics(topics, topicPath, "", isSelected); //$NON-NLS-1$
167             }
168             buf.append("</node>\n"); //$NON-NLS-1$
169             
170         }
171         
172         private ITopic[] getTopicPathFromRootPath(IToc toc) {
173             ITopic[] topicPath;
174             // Determine the topicPath from the path passed in as a parameter
175             int[] rootPath = tocData.getRootPath();
176             if (rootPath == null) {
177                 return null;
178             }
179             int pathLength = rootPath.length;
180             topicPath = new ITopic[pathLength];
181             ITopic[] children = EnabledTopicUtils.getEnabled(toc.getTopics());
182             for (int i = 0; i < pathLength; i++) {
183                 int index = rootPath[i];
184                 if (index < children.length) {
185                     topicPath[i] = children[index];
186                     children = EnabledTopicUtils.getEnabled(topicPath[i].getSubtopics());
187                 } else {
188                     return null;  // Mismatch between expected and actual children
189                 }
190             }
191             return topicPath;
192         }
193     
194         private void serializeTopic(ITopic topic, ITopic[] topicPath, boolean isSelected, String   parentPath)  {
195             ITopic[] subtopics = EnabledTopicUtils.getEnabled(topic.getSubtopics());
196             buf.append("<node"); //$NON-NLS-1$
197             if (topic.getLabel() != null) { 
198                 buf.append('\n' + "      title=\"" + XMLGenerator.xmlEscape(topic.getLabel()) + '"'); //$NON-NLS-1$
199             }
200     
201             buf.append('\n' + "      id=\"" + parentPath + "\""); //$NON-NLS-1$ //$NON-NLS-2$
202 
203             String   href = topic.getHref();
204             if (href == null) {
205                 href = "/../nav/" + tocData.getSelectedToc() + '_' + parentPath; //$NON-NLS-1$
206             }
207             buf.append('\n' + "      HREF=\"" + XMLGenerator.xmlEscape( //$NON-NLS-1$
208                     UrlUtil.getHelpURL(href)) + '"');
209             if (subtopics.length == 0 ) {
210                 buf.append('\n' + "      is_leaf=\"true\"" ); //$NON-NLS-1$
211             }
212             if (isSelected && requestKind == REQUEST_SHOW_IN_TOC) {
213                 buf.append('\n' + "      is_selected=\"true\"" ); //$NON-NLS-1$
214                 buf.append('\n' + "      is_highlighted=\"true\"" ); //$NON-NLS-1$  
215             }
216             String   icon; 
217             if (subtopics.length == 0) {
218                 icon = "topic"; //$NON-NLS-1$
219             } else if (topic.getHref() == null) {
220                 icon = "container_obj"; //$NON-NLS-1$
221             } else {
222                 icon = "container_topic"; //$NON-NLS-1$
223             }
224             buf.append('\n' + "      image=\"" + icon + "\""); //$NON-NLS-1$ //$NON-NLS-2$
225             
226             buf.append(">\n"); //$NON-NLS-1$
227             serializeChildTopics(subtopics, topicPath, parentPath, isSelected);
228             buf.append("</node>\n"); //$NON-NLS-1$  
229         }
230     
231         private void serializeChildTopics(ITopic[] childTopics, ITopic[] topicPath, String   parentPath, boolean parentIsSelected) {
232             if (parentIsSelected && requestKind == REQUEST_SHOW_CHILDREN) {
233                 // Show the children of this node
234                 for (int subtopic = 0; subtopic < childTopics.length; subtopic++) {
235                     serializeTopic(childTopics[subtopic], null, false, addSuffix(parentPath, subtopic));
236                 }
237             } else if (topicPath != null) {
238                 for (int subtopic = 0; subtopic < childTopics.length; subtopic++) {
239                     if (topicPath[0].getLabel().equals(childTopics[subtopic].getLabel())) {
240                         ITopic[] newPath = null;
241                         if (topicPath.length > 1) {
242                             newPath = new ITopic[topicPath.length - 1];
243                             System.arraycopy(topicPath, 1, newPath, 0, topicPath.length - 1);
244                         }
245                         serializeTopic(childTopics[subtopic], newPath, topicPath.length == 1, addSuffix(parentPath, subtopic));
246                     } else {
247                         serializeTopic(childTopics[subtopic], null, false, addSuffix(parentPath, subtopic));
248                     }
249                 }
250             } 
251         }
252 
253         private String   addSuffix(String   parentPath, int subtopic) {
254             if (parentPath.length() == 0) {
255                 return parentPath + subtopic;
256             } 
257             return parentPath + '_' + subtopic;
258         }
259     }
260 
261 }
262
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