1 /*
2 * Copyright 1999,2004 The Apache Software Foundation.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.apache.commons.feedparser;
18
19 import java.util.Locale;
20
21 import org.apache.commons.feedparser.tools.RFC3066LocaleParser;
22 import org.jaxen.jdom.JDOMXPath;
23 import org.jdom.Attribute;
24 import org.jdom.Element;
25
26 /**
27 * Basic parser support common between RSS, Atom, and FOAF feed impls.
28 *
29 * @author <a href="mailto:burton@apache.org">Kevin A. Burton (burtonator)</a>
30 * @version $Id: BaseParser.java 373614 2006-01-30 22:31:21Z mvdb $
31 */
32 public class BaseParser {
33
34 protected static void doLocale( FeedParserState state,
35 FeedParserListener listener,
36 Element element ) throws Exception {
37
38 if ( element == null )
39 return;
40
41 if ( state.metaFeedParserlistener == null )
42 return;
43
44 String l = getLocaleString( element );
45
46 if ( l != null ) {
47
48 Locale locale = RFC3066LocaleParser.parse( l );
49
50 if ( locale != null )
51 state.metaFeedParserlistener.onLocale( state, locale );
52
53 }
54
55 }
56
57 protected static void doLocaleEnd( FeedParserState state,
58 FeedParserListener listener,
59 Element element )
60 throws Exception {
61
62 if ( element == null )
63 return;
64
65 if ( state.metaFeedParserlistener == null )
66 return;
67
68 String l = getLocaleString( element );
69
70 if ( l != null )
71 state.metaFeedParserlistener.onLocaleEnd();
72
73 }
74
75 protected static String getLocaleString( Element element ) {
76
77 //hm.. crap. how do we get the 'xml' namespace here?
78 Attribute attr = element.getAttribute( "lang" );
79
80 if ( attr != null )
81 return attr.getValue();
82
83 //when stil null see that we have dc:language
84
85 Element lang = element.getChild( "language", NS.DC );
86
87 if ( lang != null )
88 return lang.getText();
89
90 //fall over to just using "language" and if it isn't a local string we
91 //won't parse it. This is for RSS 0.91 and RSS 2.0 content.
92 lang = element.getChild( "language" );
93
94 if ( lang != null )
95 return lang.getText();
96
97 return null;
98
99 }
100
101 // **** shared code for all parsers *****************************************
102
103 //FIXME: unify this with RSSFeedParser.getChildElementTextByName
104 protected static String selectText( String query, Element element ) throws Exception {
105
106 JDOMXPath xpath = new JDOMXPath( query );
107 xpath.setNamespaceContext( NS.context );
108
109 //perform onChannel method... (title, link, description)
110 Element e = (Element)xpath.selectSingleNode( element );
111
112 if ( e == null )
113 return null;
114
115 String result = e.getText();
116
117 //The normalize method of XML SHOULD take care of this but for some
118 //reason it doesnt.
119 if ( result != null )
120 result = result.trim();
121
122 return result;
123
124 }
125
126 /**
127 * Regardless of namespace, get the child node text by name or null if it is not found.
128 *
129 *
130 */
131 protected static String getChildElementTextByName( FeedParserState state,
132 String name ) throws Exception {
133
134 //FIXME: this can be rewritten to use getChild()
135
136 JDOMXPath xpath = new JDOMXPath( "descendant::*[local-name() = '" + name + "']" );
137 Object resultNode = xpath.selectSingleNode( state.current );
138
139 String resultText = null;
140
141 if ( resultNode != null )
142 resultText = ((Element)resultNode).getText();
143
144 //The normalize method of XML SHOULD take care of this but for some
145 //reason it doesnt.
146 if ( resultText != null )
147 resultText = resultText.trim();
148
149 return resultText;
150
151 }
152
153 }