1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one
3  * or more contributor license agreements. See the NOTICE file
4  * distributed with this work for additional information
5  * regarding copyright ownership. The ASF licenses this file
6  * to you 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  * $Id: ElemExsltFunction.java 468643 2006-10-28 06:56:03Z minchau $
20  */
21 package org.apache.xalan.templates;
22 
23 import javax.xml.transform.TransformerException;
24 
25 import org.apache.xalan.extensions.ExtensionNamespaceSupport;
26 import org.apache.xalan.transformer.TransformerImpl;
27 import org.apache.xpath.VariableStack;
28 import org.apache.xpath.XPathContext;
29 import org.apache.xpath.objects.XObject;
30 
31 import org.w3c.dom.Node;
32 import org.w3c.dom.NodeList;
33 
34 
35 /**
36  * Implement func:function.
37  * @xsl.usage advanced
38  */
39 public class ElemExsltFunction extends ElemTemplate
40 {
41     static final long serialVersionUID = 272154954793534771L;
42   /**
43    * Get an integer representation of the element type.
44    *
45    * @return An integer representation of the element, defined in the
46    *     Constants class.
47    * @see org.apache.xalan.templates.Constants
48    */
getXSLToken()49   public int getXSLToken()
50   {
51     return Constants.EXSLT_ELEMNAME_FUNCTION;
52   }
53 
54    /**
55    * Return the node name, defined in the
56    *     Constants class.
57    * @see org.apache.xalan.templates.Constants
58    * @return The node name
59    *
60    */
getNodeName()61   public String getNodeName()
62   {
63     return Constants.EXSLT_ELEMNAME_FUNCTION_STRING;
64   }
65 
execute(TransformerImpl transformer, XObject[] args)66   public void execute(TransformerImpl transformer, XObject[] args)
67           throws TransformerException
68   {
69     XPathContext xctxt = transformer.getXPathContext();
70     VariableStack vars = xctxt.getVarStack();
71 
72     // Increment the frame bottom of the variable stack by the
73     // frame size
74     int thisFrame = vars.getStackFrame();
75     int nextFrame = vars.link(m_frameSize);
76 
77     if (m_inArgsSize < args.length) {
78       throw new TransformerException ("function called with too many args");
79     }
80 
81     // Set parameters,
82     // have to clear the section of the stack frame that has params.
83     if (m_inArgsSize > 0) {
84       vars.clearLocalSlots(0, m_inArgsSize);
85 
86       if (args.length > 0) {
87         vars.setStackFrame(thisFrame);
88         NodeList children = this.getChildNodes();
89 
90         for (int i = 0; i < args.length; i ++) {
91           Node child = children.item(i);
92           if (children.item(i) instanceof ElemParam) {
93             ElemParam param = (ElemParam)children.item(i);
94             vars.setLocalVariable(param.getIndex(), args[i], nextFrame);
95           }
96         }
97 
98         vars.setStackFrame(nextFrame);
99       }
100     }
101 
102     //  Removed ElemTemplate 'push' and 'pop' of RTFContext, in order to avoid losing the RTF context
103     //  before a value can be returned. ElemExsltFunction operates in the scope of the template that called
104     //  the function.
105     //  xctxt.pushRTFContext();
106 
107     vars.setStackFrame(nextFrame);
108     transformer.executeChildTemplates(this, true);
109 
110     // Reset the stack frame after the function call
111     vars.unlink(thisFrame);
112 
113     // Following ElemTemplate 'pop' removed -- see above.
114     // xctxt.popRTFContext();
115 
116   }
117 
118   /**
119    * Called after everything else has been
120    * recomposed, and allows the function to set remaining
121    * values that may be based on some other property that
122    * depends on recomposition.
123    */
compose(StylesheetRoot sroot)124   public void compose(StylesheetRoot sroot) throws TransformerException
125   {
126     super.compose(sroot);
127 
128     // Register the function namespace (if not already registered).
129     String namespace = getName().getNamespace();
130     String handlerClass = sroot.getExtensionHandlerClass();
131     Object[] args ={namespace, sroot};
132     ExtensionNamespaceSupport extNsSpt =
133                          new ExtensionNamespaceSupport(namespace, handlerClass, args);
134     sroot.getExtensionNamespacesManager().registerExtension(extNsSpt);
135     // Make sure there is a handler for the EXSLT functions namespace
136     // -- for isElementAvailable().
137     if (!(namespace.equals(Constants.S_EXSLT_FUNCTIONS_URL)))
138     {
139       namespace = Constants.S_EXSLT_FUNCTIONS_URL;
140       args = new Object[]{namespace, sroot};
141       extNsSpt = new ExtensionNamespaceSupport(namespace, handlerClass, args);
142       sroot.getExtensionNamespacesManager().registerExtension(extNsSpt);
143     }
144   }
145 }
146