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Java > Open Source Codes > org > htmlparser > util > IteratorImpl


1 // HTMLParser Library $Name: v1_5_20050313 $ - A java-based parser for HTML
2 // http://sourceforge.org/projects/htmlparser
3 // Copyright (C) 2004 Somik Raha
4 //
5 // Revision Control Information
6 //
7 // $Source: /cvsroot/htmlparser/htmlparser/src/org/htmlparser/util/IteratorImpl.java,v $
8 // $Author: derrickoswald $
9 // $Date: 2005/03/13 14:51:46 $
10 // $Revision: 1.43 $
11 //
12 // This library is free software; you can redistribute it and/or
13 // modify it under the terms of the GNU Lesser General Public
14 // License as published by the Free Software Foundation; either
15 // version 2.1 of the License, or (at your option) any later version.
16 //
17 // This library is distributed in the hope that it will be useful,
18 // but WITHOUT ANY WARRANTY; without even the implied warranty of
19 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 // Lesser General Public License for more details.
21 //
22 // You should have received a copy of the GNU Lesser General Public
23 // License along with this library; if not, write to the Free Software
24 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 //
26
27 package org.htmlparser.util;
28
29 import org.htmlparser.Node;
30 import org.htmlparser.Tag;
31 import org.htmlparser.lexer.Cursor;
32 import org.htmlparser.lexer.Lexer;
33 import org.htmlparser.lexer.Page;
34 import org.htmlparser.scanners.Scanner;
35 import org.htmlparser.util.NodeIterator;
36
37 public class IteratorImpl implements NodeIterator
38 {
39     Lexer mLexer;
40     ParserFeedback mFeedback;
41     Cursor mCursor;
42
43     public IteratorImpl (Lexer lexer, ParserFeedback fb)
44     {
45         mLexer = lexer;
46         mFeedback = fb;
47         mCursor = new Cursor (mLexer.getPage (), 0);
48     }
49
50     /**
51      * Check if more nodes are available.
52      * @return <code>true</code> if a call to <code>nextNode()</code> will succeed.
53      */
54     public boolean hasMoreNodes() throws ParserException
55     {
56         boolean ret;
57
58         mCursor.setPosition (mLexer.getPosition ());
59         ret = Page.EOF != mLexer.getPage ().getCharacter (mCursor); // more characters?
60
61         return (ret);
62     }
63
64     /**
65      * Get the next node.
66      * @return The next node in the HTML stream, or null if there are no more nodes.
67      * @exception ParserException If an unrecoverable error occurs.
68      */
69     public Node nextNode () throws ParserException
70     {
71         Tag tag;
72         Scanner scanner;
73         NodeList stack;
74         Node ret;
75
76         try
77         {
78             ret = mLexer.nextNode ();
79             if (null != ret)
80             {
81                 // kick off recursion for the top level node
82 if (ret instanceof Tag)
83                 {
84                     tag = (Tag)ret;
85                     if (!tag.isEndTag ())
86                     {
87                         // now recurse if there is a scanner for this type of tag
88 scanner = tag.getThisScanner ();
89                         if (null != scanner)
90                         {
91                             stack = new NodeList ();
92                             ret = scanner.scan (tag, mLexer, stack);
93                         }
94                     }
95                 }
96             }
97         }
98         catch (ParserException pe)
99         {
100             throw pe; // no need to wrap an existing ParserException
101 }
102         catch (Exception JavaDoc e)
103         {
104             StringBuffer JavaDoc msgBuffer = new StringBuffer JavaDoc ();
105             msgBuffer.append ("Unexpected Exception occurred while reading ");
106             msgBuffer.append (mLexer.getPage ().getUrl ());
107             msgBuffer.append (", in nextNode");
108             // TODO: appendLineDetails (msgBuffer);
109 ParserException ex = new ParserException (msgBuffer.toString (), e);
110             mFeedback.error (msgBuffer.toString (), ex);
111             throw ex;
112         }
113         
114         return (ret);
115     }
116 }
117
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