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Java > Open Source Codes > org > apache > jetspeed > util > servlet > EcsStylesheetElement


1 /*
2  * Copyright 2000-2001,2004 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.jetspeed.util.servlet;
18
19 // Java classes
20 import java.io.OutputStream JavaDoc;
21 import java.io.PrintWriter JavaDoc;
22 import java.io.StringReader JavaDoc;
23 import java.util.Map JavaDoc;
24
25 // SAX Classes
26 import org.xml.sax.InputSource JavaDoc;
27
28 // ECS classes
29 import org.apache.ecs.ConcreteElement;
30
31 // Jetspeed classes
32 import org.apache.jetspeed.services.logging.JetspeedLogFactoryService;
33 import org.apache.jetspeed.services.logging.JetspeedLogger;
34 import org.apache.jetspeed.util.SimpleTransform;
35
36 /**
37  * NOTE: The use of Ecs for aggregating portlet content is deprecated!
38  * This utility class will be removed once we don't have the ecs
39  * dependency any more.
40  *
41  * EcsStylesheetElement encapsulates XML data, a stylesheet and the parameters for
42  * processing the XML data within the context of ECS markup.
43  *
44  * This is a workaround to allow invoking stylesheets from JetSpeed Portlets without
45  * buffering strings with the transformation results. Transformation is invoked when
46  * traversal of an ECS tree during writing reaches the EcsStylesheetElement.
47  *
48  * @author Thomas Schaeck (schaeck@de.ibm.com)
49  */
50 public class EcsStylesheetElement extends ConcreteElement
51 {
52     /**
53      * Static initialization of the logger for this class
54      */
55     private static final JetspeedLogger logger = JetspeedLogFactoryService.getLogger(EcsStylesheetElement.class.getName());
56     
57     /**
58      * Processes the referenced XML content using the referenced XSLT stylesheet and
59      * parameters.
60      *
61      * @param out The output stream to which the result shall be written.
62      */
63      public void output(OutputStream JavaDoc out)
64      {
65         output(new PrintWriter JavaDoc(out));
66      }
67
68     /**
69      * Processes the referenced XML content using the referenced XSLT stylesheet and
70      * parameters.
71      *
72      * @param out The print writer to be used for writing the result.
73      */
74     public void output(PrintWriter JavaDoc out)
75     {
76         try {
77
78             StringReader JavaDoc rdr = new StringReader JavaDoc (SimpleTransform.transform( content_, stylesheet_, params_ ) );
79             int count = 0;
80             char buff[] = new char[1024];
81             while( (count = rdr.read( buff, 0, buff.length ) ) > 0 ) {
82                 out.write( buff, 0, count );
83                 }
84
85         /* // Get a new XSLT Processor
86             XSLTProcessor processor = XSLTProcessorFactory.getProcessor();
87
88             // set the parameters for the stylesheet
89             if (params_ != null)
90             {
91                 Enumeration keys = params_.keys();
92                 while (keys.hasMoreElements())
93                 {
94                     String name = (String) keys.nextElement();
95                     processor.setStylesheetParam(name, (String) params_.get(name));
96                 }
97             }
98
99             // process the stylesheet
100             processor.process( content_, stylesheet_, new XSLTResultTarget(out) ); */
101
102             } catch (Exception JavaDoc e)
103             {
104                 String JavaDoc message = "ECSStylesheetElement.output(PrintWriter): error processing stylesheet" + e.getMessage();
105                 logger.error(message, e);
106                 out.print(message);
107                 e.printStackTrace(out);
108             }
109     }
110
111
112     /** XML content to be processed. */
113     private InputSource JavaDoc content_;
114
115     /** Parameters to be used by the stylesheet. */
116     private Map JavaDoc params_;
117
118     /** XSLT stylesheet to be used for rendering the content. */
119     private InputSource JavaDoc stylesheet_;
120
121     /**
122      * Construct an ECS element that will render a given XML dicument using a given
123      * stylesheet and parameters when one of its output methods is invoked.
124      *
125      * @param content XML content to be processed
126      * @param stylesheet XSLT stylesheet to be used for processing the content
127      * @param params parameters for the stylesheet
128      */
129     public EcsStylesheetElement( InputSource JavaDoc content,
130                                  InputSource JavaDoc stylesheet,
131                                  Map JavaDoc params )
132     {
133         content_ = content;
134         stylesheet_ = stylesheet;
135         params_ = params;
136
137     }
138
139 }
140
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