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Java > Open Source Codes > org > apache > commons > jelly > tags > core > FileTag


1 /*
2  * Copyright 2002,2004 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 package org.apache.commons.jelly.tags.core;
17
18 import java.io.FileNotFoundException JavaDoc;
19 import java.io.FileOutputStream JavaDoc;
20 import java.io.IOException JavaDoc;
21 import java.io.OutputStreamWriter JavaDoc;
22 import java.io.StringWriter JavaDoc;
23 import java.io.UnsupportedEncodingException JavaDoc;
24 import java.io.Writer JavaDoc;
25
26 import org.apache.commons.jelly.JellyTagException;
27 import org.apache.commons.jelly.TagSupport;
28 import org.apache.commons.jelly.XMLOutput;
29 import org.apache.commons.jelly.util.SafeContentHandler;
30 import org.dom4j.io.HTMLWriter;
31 import org.dom4j.io.OutputFormat;
32 import org.dom4j.io.XMLWriter;
33 import org.xml.sax.SAXException JavaDoc;
34
35 /**
36  * A tag that pipes its body to a file denoted by the name attribute or to an in memory String
37  * which is then output to a variable denoted by the var variable.
38  *
39  * @author <a HREF="mailto:vinayc@apache.org">Vinay Chandran</a>
40  */
41 public class FileTag extends TagSupport {
42     private boolean doAppend = false;
43     private String JavaDoc var;
44     private String JavaDoc name;
45     private boolean omitXmlDeclaration = false;
46     private String JavaDoc outputMode = "xml";
47     private boolean prettyPrint;
48     private String JavaDoc encoding;
49
50     public FileTag(){
51     }
52
53     // Tag interface
54 //-------------------------------------------------------------------------
55 public void doTag(final XMLOutput output) throws JellyTagException {
56         try {
57             if ( name != null ) {
58                 String JavaDoc encoding = (this.encoding != null) ? this.encoding : "UTF-8";
59                 Writer JavaDoc writer = new OutputStreamWriter JavaDoc( new FileOutputStream JavaDoc( name, doAppend ), encoding );
60                 writeBody(writer);
61             }
62             else if (var != null) {
63                 StringWriter JavaDoc writer = new StringWriter JavaDoc();
64                 writeBody(writer);
65                 String JavaDoc result = writer.toString();
66                 Object JavaDoc varValue = context.getVariable(var);
67                 // if we're appending, and var is an instance of string, append it.
68 if (doAppend && varValue instanceof String JavaDoc) {
69                     context.setVariable(var, varValue + result);
70                 } else {
71                     context.setVariable(var, result);
72                 }
73             }
74             else {
75                 throw new JellyTagException( "This tag must have either the 'name' or the 'var' variables defined" );
76             }
77         } catch (FileNotFoundException JavaDoc e) {
78             throw new JellyTagException(e);
79         } catch (UnsupportedEncodingException JavaDoc e) {
80             throw new JellyTagException(e);
81         } catch (SAXException JavaDoc e) {
82             throw new JellyTagException("could not write file",e);
83         }
84     }
85
86     // Properties
87 //-------------------------------------------------------------------------
88
89     /**
90      * Sets the file name for the output
91      */
92     public void setName(String JavaDoc name) {
93         this.name = name;
94     }
95
96     /**
97      * Sets whether the XML declaration should be output or not
98      */
99     public void setOmitXmlDeclaration(boolean omitXmlDeclaration) {
100         this.omitXmlDeclaration = omitXmlDeclaration;
101     }
102
103
104     /**
105      * Sets the output mode, whether XML or HTML
106      */
107     public void setOutputMode(String JavaDoc outputMode) {
108         this.outputMode = outputMode;
109     }
110
111     /**
112      * Sets whether pretty printing mode is turned on. The default is off so that whitespace is preserved
113      */
114     public void setPrettyPrint(boolean prettyPrint) {
115         this.prettyPrint = prettyPrint;
116     }
117
118     /**
119      * Sets the XML encoding mode, which defaults to UTF-8
120      */
121     public void setEncoding(String JavaDoc encoding) {
122         this.encoding = encoding;
123     }
124     
125     /**
126      * Sets wether to append at the end of the file
127      * (not really something you normally do with an XML file).
128      */
129     public void setAppend(boolean doAppend) {
130         this.doAppend = doAppend;
131     }
132     
133
134     /**
135      * Returns the var.
136      * @return String
137      */
138     public String JavaDoc getVar() {
139         return var;
140     }
141
142     /**
143      * Sets the var.
144      * @param var The var to set
145      */
146     public void setVar(String JavaDoc var) {
147         this.var = var;
148     }
149
150     /**
151      * Writes the body fo this tag to the given Writer
152      */
153     protected void writeBody(Writer JavaDoc writer) throws SAXException JavaDoc, JellyTagException {
154
155         XMLOutput newOutput = createXMLOutput(writer);
156         try {
157             // we need to avoid multiple start/end document events
158 newOutput.setContentHandler(
159                 new SafeContentHandler(newOutput.getContentHandler())
160             );
161             newOutput.startDocument();
162             invokeBody(newOutput);
163             newOutput.endDocument();
164         }
165         finally {
166             try { newOutput.close(); } catch (IOException JavaDoc e) {}
167         }
168     }
169
170     /**
171      * A Factory method to create a new XMLOutput from the given Writer.
172      */
173     protected XMLOutput createXMLOutput(Writer JavaDoc writer) {
174
175         OutputFormat format = null;
176         if (prettyPrint) {
177             format = OutputFormat.createPrettyPrint();
178         }
179         else {
180             format = new OutputFormat();
181         }
182         if ( encoding != null ) {
183             format.setEncoding( encoding );
184         }
185         if ( omitXmlDeclaration ) {
186             format.setSuppressDeclaration(true);
187         }
188
189         boolean isHtml = outputMode != null && outputMode.equalsIgnoreCase( "html" );
190         final XMLWriter xmlWriter = (isHtml)
191             ? new HTMLWriter(writer, format)
192             : new XMLWriter(writer, format);
193
194         xmlWriter.setEscapeText(isEscapeText());
195
196         XMLOutput answer = new XMLOutput() {
197             public void close() throws IOException JavaDoc {
198                 xmlWriter.close();
199             }
200         };
201         answer.setContentHandler(xmlWriter);
202         answer.setLexicalHandler(xmlWriter);
203         return answer;
204     }
205 }
206
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