KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > apache > velocity > runtime > directive > Parse


1 package org.apache.velocity.runtime.directive;
2
3 /*
4  * Copyright 2000-2001,2004 The Apache Software Foundation.
5  *
6  * Licensed under the Apache License, Version 2.0 (the "License");
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18
19 import java.io.IOException JavaDoc;
20 import java.io.Writer JavaDoc;
21
22 import org.apache.velocity.context.InternalContextAdapter;
23
24 import org.apache.velocity.Template;
25 import org.apache.velocity.runtime.RuntimeConstants;
26 import org.apache.velocity.runtime.parser.node.Node;
27 import org.apache.velocity.runtime.parser.node.SimpleNode;
28
29 import org.apache.velocity.exception.MethodInvocationException;
30 import org.apache.velocity.exception.ParseErrorException;
31 import org.apache.velocity.exception.ResourceNotFoundException;
32
33 /**
34  * Pluggable directive that handles the <code>#parse()</code>
35  * statement in VTL.
36  *
37  * <pre>
38  * Notes:
39  * -----
40  * 1) The parsed source material can only come from somewhere in
41  * the TemplateRoot tree for security reasons. There is no way
42  * around this. If you want to include content from elsewhere on
43  * your disk, use a link from somwhere under Template Root to that
44  * content.
45  *
46  * 2) There is a limited parse depth. It is set as a property
47  * "parse_directive.maxdepth = 10" for example. There is a 20 iteration
48  * safety in the event that the parameter isn't set.
49  * </pre>
50  *
51  * @author <a HREF="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
52  * @author <a HREF="mailto:jvanzyl@apache.org">Jason van Zyl</a>
53  * @author <a HREF="mailto:Christoph.Reck@dlr.de">Christoph Reck</a>
54  * @version $Id: Parse.java,v 1.27.4.1 2004/03/03 23:22:56 geirm Exp $
55  */
56 public class Parse extends InputBase
57 {
58     private boolean ready = false;
59
60     /**
61      * Return name of this directive.
62      */
63     public String JavaDoc getName()
64     {
65         return "parse";
66     }
67     
68     /**
69      * Return type of this directive.
70      */
71     public int getType()
72     {
73         return LINE;
74     }
75     
76     /**
77      * iterates through the argument list and renders every
78      * argument that is appropriate. Any non appropriate
79      * arguments are logged, but render() continues.
80      */
81     public boolean render( InternalContextAdapter context,
82                            Writer JavaDoc writer, Node node)
83         throws IOException JavaDoc, ResourceNotFoundException, ParseErrorException,
84                MethodInvocationException
85     {
86         /*
87          * did we get an argument?
88          */
89         if ( node.jjtGetChild(0) == null)
90         {
91             rsvc.error( "#parse() error : null argument" );
92             return false;
93         }
94         
95         /*
96          * does it have a value? If you have a null reference, then no.
97          */
98         Object JavaDoc value = node.jjtGetChild(0).value( context );
99
100         if ( value == null)
101         {
102             rsvc.error( "#parse() error : null argument" );
103             return false;
104         }
105
106         /*
107          * get the path
108          */
109         String JavaDoc arg = value.toString();
110         
111         /*
112          * see if we have exceeded the configured depth.
113          * If it isn't configured, put a stop at 20 just in case.
114          */
115
116         Object JavaDoc[] templateStack = context.getTemplateNameStack();
117
118         if ( templateStack.length >=
119                 rsvc.getInt(RuntimeConstants.PARSE_DIRECTIVE_MAXDEPTH, 20) )
120         {
121             StringBuffer JavaDoc path = new StringBuffer JavaDoc();
122
123             for( int i = 0; i < templateStack.length; ++i)
124             {
125                 path.append( " > " + templateStack[i] );
126             }
127
128             rsvc.error( "Max recursion depth reached (" +
129                 templateStack.length + ")" + " File stack:" + path );
130             return false;
131         }
132
133         /*
134          * now use the Runtime resource loader to get the template
135          */
136        
137         Template t = null;
138
139         try
140         {
141             t = rsvc.getTemplate( arg, getInputEncoding(context) );
142         }
143         catch ( ResourceNotFoundException rnfe )
144         {
145             /*
146              * the arg wasn't found. Note it and throw
147              */
148              
149             rsvc.error("#parse(): cannot find template '" + arg +
150                        "', called from template " +
151                        context.getCurrentTemplateName() + " at (" +
152                        getLine() + ", " + getColumn() + ")" );
153             throw rnfe;
154         }
155         catch ( ParseErrorException pee )
156         {
157             /*
158              * the arg was found, but didn't parse - syntax error
159              * note it and throw
160              */
161
162             rsvc.error("#parse(): syntax error in #parse()-ed template '" +
163                        arg + "', called from template " +
164                        context.getCurrentTemplateName() + " at (" +
165                        getLine() + ", " + getColumn() + ")" );
166                 
167             throw pee;
168         }
169         catch ( Exception JavaDoc e)
170         {
171             rsvc.error("#parse() : arg = " + arg + ". Exception : " + e);
172             return false;
173         }
174     
175         /*
176          * and render it
177          */
178         try
179         {
180             context.pushCurrentTemplateName(arg);
181             ((SimpleNode) t.getData()).render( context, writer );
182         }
183         catch ( Exception JavaDoc e )
184         {
185             /*
186              * if it's a MIE, it came from the render.... throw it...
187              */
188
189             if ( e instanceof MethodInvocationException)
190             {
191                 throw (MethodInvocationException) e;
192             }
193
194             rsvc.error( "Exception rendering #parse( " + arg + " ) : " + e );
195             return false;
196         }
197         finally
198         {
199             context.popCurrentTemplateName();
200         }
201
202         return true;
203     }
204 }
205
206
Popular Tags