TagParser


1   ////////////////////////////////////////////////////////////////////////////////
2   // checkstyle: Checks Java source code for adherence to a set of rules.
3   // Copyright (C) 2001-2005  Oliver Burn
4   //
5   // This library is free software; you can redistribute it and/or
6   // modify it under the terms of the GNU Lesser General Public
7   // License as published by the Free Software Foundation; either
8   // version 2.1 of the License, or (at your option) any later version.
9   //
10  // This library 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 GNU
13  // Lesser General Public License for more details.
14  //
15  // You should have received a copy of the GNU Lesser General Public
16  // License along with this library; if not, write to the Free Software
17  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  ////////////////////////////////////////////////////////////////////////////////
19  package com.puppycrawl.tools.checkstyle.checks.javadoc;
20  
21  import java.util.LinkedList  ;
22  import java.util.List  ;
23  
24  /**
25   * Helper class used to parse HTML tags from a single line of text.
26   * Just the beginning of the HTML tag is located.  No attempt is made to
27   * parse out the complete tag, particularly since some of the tag
28   * parameters could be located on the following line of text.  The
29   * <code>hasNextTag</code> and <code>nextTag</code> methods are used
30   * to iterate through the HTML tags that were found on the line of text.
31   *
32   * @author Chris Stillwell
33   */
34  class TagParser
35  {
36      /** List of HtmlTags found on the input line of text. */
37      private final List   mTags = new LinkedList  ();
38  
39      /**
40       * Constructs a TagParser and finds the first tag if any.
41       * @param aText the line of text to parse.
42       * @param aLineNo the source line number.
43       */
44      public TagParser(String  [] aText, int aLineNo)
45      {
46          parseTags(aText, aLineNo);
47      }
48  
49      /**
50       * Returns the next available HtmlTag.
51       * @return a HtmlTag or <code>null</code> if none available.
52       * @throws IndexOutOfBoundsException if there are no HtmlTags
53       *         left to return.
54       */
55      public HtmlTag nextTag()
56      {
57          return (HtmlTag) mTags.remove(0);
58      }
59  
60      /**
61       * Indicates if there are any more HtmlTag to retrieve.
62       * @return <code>true</code> if there are more tags.
63       */
64      public boolean hasNextTag()
65      {
66          return (mTags.size() > 0);
67      }
68  
69      /**
70       * Performs lazy initialization on the internal tags List
71       * and adds the tag.
72       * @param aTag the HtmlTag to add.
73       */
74      private void add(HtmlTag aTag)
75      {
76          mTags.add(aTag);
77      }
78  
79      /**
80       * Parses the text line for any HTML tags and adds them to the internal
81       * List of tags.
82       * @param aText the source line to parse.
83       * @param aLineNo the source line number.
84       */
85      private void parseTags(String  [] aText, int aLineNo)
86      {
87          final int nLines = aText.length;
88          Point position = new Point(0, 0);
89  
90          position = findChar(aText, '<', position);
91          while (position.getLineNo() < nLines) {
92              // if this is html comment then skip it
93              if (isCommentTag(aText, position)) {
94                  position = skipHtmlComment(aText, position);
95              }
96              else if (!isTag(aText, position)) {
97                  position = getNextCharPos(aText, position);
98              }
99              else {
100                 // find end of tag
101                 final Point endTag = findChar(aText, '>', position);
102                 final boolean incompleteTag = (endTag.getLineNo() >= nLines);
103                 // get tag id (one word)
104                 final String   tagId =
105                     (incompleteTag ? "" : getTagId(aText, position));
106                 // is this closed tag
107                 final boolean closedTag =
108                     ((endTag.getLineNo() < nLines) && (endTag.getColumnNo() > 0)
109                      && (aText[endTag.getLineNo()]
110                      .charAt(endTag.getColumnNo() - 1) == '/'));
111                 // add new tag
112                 add(new HtmlTag(tagId,
113                                 position.getLineNo() + aLineNo,
114                                 position.getColumnNo(),
115                                 closedTag,
116                                 incompleteTag,
117                                 aText[position.getLineNo()]));
118                 position = endTag;
119             }
120             position = findChar(aText, '<', position);
121         }
122     }
123 
124     /**
125      * Checks if the given position is start one for HTML tag.
126      * @param aText text of javadoc comments.
127      * @param aPos position to check.
128      * @return <code>true</code> some HTML tag starts from given position.
129      */
130     private boolean isTag(String  [] aText, Point aPos)
131     {
132         final int column = aPos.getColumnNo() + 1;
133         final String   text = aText[aPos.getLineNo()];
134 
135         return (((column < text.length())
136                 && (((text.charAt(column) >= 'A')
137                      && (text.charAt(column) <= 'Z'))
138                     || ((text.charAt(column) >= 'a')
139                         && (text.charAt(column) <= 'z'))
140                     || (text.charAt(column) == '/')))
141                 || (column >= text.length()));
142     }
143 
144     /**
145      * Parse tag id.
146      * @param aText text of javadoc comments.
147      * @param aTagStart start position of the tag
148      * @return id for given tag
149      */
150     private String   getTagId(String  [] aText, Point aTagStart)
151     {
152         int column = aTagStart.getColumnNo() + 1;
153         String   text = aText[aTagStart.getLineNo()];
154         if (column >= text.length()) {
155             return "";
156         }
157 
158         if (text.charAt(column) == '/') {
159             column++;
160         }
161 
162         text = text.substring(column).trim();
163         column = 0;
164 
165         while ((column < text.length())
166                && (((text.charAt(column) >= 'A')
167                     && (text.charAt(column) <= 'Z'))
168                    || ((text.charAt(column) >= 'a')
169                        && (text.charAt(column) <= 'z'))
170                    || ((text.charAt(column) >= '0')
171                        && (text.charAt(column) <= '9'))))
172         {
173             column++;
174         }
175 
176         return text.substring(0, column);
177     }
178 
179     /**
180      * If this is a HTML-comments.
181      * @param aText text of javadoc comments
182      * @param aPos position to check
183      * @return <code>true</code> if HTML-comments
184      *         starts form given position.
185      */
186     private boolean isCommentTag(String  [] aText, Point aPos)
187     {
188         return aText[aPos.getLineNo()].startsWith("<!--", aPos.getColumnNo());
189     }
190 
191     /**
192      * Skips HTML comments.
193      * @param aText text of javadoc comments.
194      * @param aFrom start position of HTML-comments
195      * @return position after HTML-comments
196      */
197     private Point skipHtmlComment(String  [] aText, Point aFrom)
198     {
199         Point to = aFrom;
200         to = findChar(aText, '>', to);
201         while ((to.getLineNo() < aText.length)
202                && !aText[to.getLineNo()]
203                .substring(0, to.getColumnNo()).endsWith("-->"))
204         {
205             to = findChar(aText, '>', getNextCharPos(aText, to));
206         }
207         return to;
208     }
209 
210     /**
211      * Finds next occurence of given character.
212      * @param aText text to search
213      * @param aChar character to search
214      * @param aFrom position to start search
215      * @return position of next occurence of given character
216      */
217     private Point findChar(String  [] aText, char aChar, Point aFrom)
218     {
219         Point curr = new Point(aFrom.getLineNo(), aFrom.getColumnNo());
220         while ((curr.getLineNo() < aText.length)
221                && (aText[curr.getLineNo()].charAt(curr.getColumnNo()) != aChar))
222         {
223             curr = getNextCharPos(aText, curr);
224         }
225 
226         return curr;
227     }
228 
229     /**
230      * Returns position of next comment character, skips
231      * whitespaces and asteriks.
232      * @param aText to search.
233      * @param aFrom location to search from
234      * @return location of the next character.
235      */
236     private Point getNextCharPos(String  [] aText, Point aFrom)
237     {
238         int line = aFrom.getLineNo();
239         int column = aFrom.getColumnNo() + 1;
240         while ((line < aText.length) && (column >= aText[line].length())) {
241             // go to the next line
242             line++;
243             column = 0;
244             if (line < aText.length) {
245                 //skip beginning spaces and stars
246                 final String   currentLine = aText[line];
247                 while ((column < currentLine.length())
248                        && (Character.isWhitespace(currentLine.charAt(column))
249                            || (currentLine.charAt(column) == '*')))
250                 {
251                     column++;
252                     if ((column < currentLine.length())
253                         && (currentLine.charAt(column - 1) == '*')
254                         && (currentLine.charAt(column) == '/'))
255                     {
256                         // this is end of comment
257                         column = currentLine.length();
258                     }
259                 }
260             }
261         }
262 
263         return new Point(line, column);
264     }
265 }
266 
267 /**
268  * Represents current position in the text.
269  * @author o_sukholsky
270  */
271 final class Point
272 {
273     /** line number. */
274     private final int mLine;
275     /** clumn number.*/
276     private final int mColumn;
277 
278     /**
279      * Creates new <code>Point</code> instance.
280      * @param aLineNo line number
281      * @param aColumnNo column number
282      */
283     public Point(int aLineNo, int aColumnNo)
284     {
285         mLine = aLineNo;
286         mColumn = aColumnNo;
287     }
288 
289     /**
290      * Getter for line number.
291      * @return line number of the position.
292      */
293     public int getLineNo()
294     {
295         return mLine;
296     }
297 
298     /**
299      * Getter for column number.
300      * @return column number of the position.
301      */
302     public int getColumnNo()
303     {
304         return mColumn;
305     }
306 }
307
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