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Java > Open Source Codes > org > apache > taglibs > xtags > xpath > ReplaceTag


1 /*
2  * Copyright 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.taglibs.xtags.xpath;
18
19 import java.io.StringReader JavaDoc;
20 import java.util.Iterator JavaDoc;
21 import java.util.List JavaDoc;
22
23 import javax.servlet.jsp.tagext.BodyTagSupport JavaDoc;
24 import javax.servlet.jsp.JspException JavaDoc;
25
26 import org.dom4j.Branch;
27 import org.dom4j.Document;
28 import org.dom4j.DocumentHelper;
29 import org.dom4j.DocumentException;
30 import org.dom4j.Element;
31 import org.dom4j.Node;
32 import org.dom4j.io.SAXReader;
33
34 import org.apache.taglibs.xtags.util.JspVariableContext;
35
36 /** The replace tag parses it's body (as an XML fragment) and replaces the contents to the
37   * current node with this new XML fragment. The current node must be an Element.
38   *
39   * @author James Elson
40   */
41 public class ReplaceTag extends AbstractBodyTag {
42     
43     public ReplaceTag() {
44     }
45
46     public int doEndTag() throws JspException JavaDoc {
47         Object JavaDoc context = TagHelper.getInputNodes(pageContext, this, false );
48         if (context == null) {
49             logInfo( "No current node to replace" );
50             return EVAL_PAGE;
51         }
52         
53         try {
54             String JavaDoc xmlFragment = null;
55             if (bodyContent != null) {
56                 xmlFragment = bodyContent.getString();
57             }
58             if (context instanceof List JavaDoc) {
59                 List JavaDoc els = (List JavaDoc )context;
60                 if (els.size() > 1) {
61                     throw new JspException JavaDoc( "Current context contains more than one node");
62                 }
63                 if (els.size() == 1) {
64                     context = els.get(0);
65                 }
66             }
67             if (context instanceof Document) {
68                 if (xmlFragment == null) {
69                     throw new JspException JavaDoc( "Cannot replace document with empty body");
70                 }
71                 Document sourceDoc = (Document) context;
72                 Document newDoc = DocumentHelper.parseText( xmlFragment );
73
74                 // clear source doc contents
75 sourceDoc.clearContent();
76                 for ( int i = 0, size = newDoc.nodeCount(); i < size; i++ ) {
77                     Node node = newDoc.node(i);
78                     // detach from new doc
79 node.detach();
80                     // add to source
81 sourceDoc.add( node );
82                 }
83             } else {
84                 if (! (context instanceof Element) ) {
85                     throw new JspException JavaDoc( "Current node is not an Element: "+context.getClass().getName() );
86                 }
87                 Element element = (Element)context;
88
89                 SAXReader reader = new SAXReader();
90
91                 if (element.isRootElement()) {
92                     if (xmlFragment == null) {
93                         throw new JspException JavaDoc( "Cannot replace root element with empty body");
94                     }
95                     Document newDoc = DocumentHelper.parseText( xmlFragment );
96                     Document sourceDoc = element.getDocument();
97                     Element newRoot = newDoc.getRootElement();
98                     newRoot.detach();
99                     sourceDoc.setRootElement(newRoot);
100                 } else {
101                     Element parent = element.getParent();
102                     List JavaDoc parentContent = parent.content();
103                     int index = parentContent.indexOf(element);
104                     parentContent.remove(index);
105                     if (xmlFragment != null) {
106                         Document newDoc = DocumentHelper.parseText( "<dummy>"+xmlFragment+"</dummy>" );
107                         parentContent.addAll(index, newDoc.getRootElement().content() );
108                     }
109                 }
110             }
111         } catch (DocumentException e) {
112             handleException(e);
113         }
114         return EVAL_PAGE;
115     }
116
117     public void release() {
118         super.release();
119     }
120 }
121
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