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 */
21package org.apache.xalan.templates;
22
23import javax.xml.transform.TransformerException;
24
25import org.apache.xalan.extensions.ExtensionNamespaceSupport;
26import org.apache.xalan.transformer.TransformerImpl;
27import org.apache.xpath.VariableStack;
28import org.apache.xpath.XPathContext;
29import org.apache.xpath.objects.XObject;
30
31import org.w3c.dom.Node;
32import org.w3c.dom.NodeList;
33
34
35/**
36 * Implement func:function.
37 * @xsl.usage advanced
38 */
39public 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   */
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   */
61  public String getNodeName()
62  {
63    return Constants.EXSLT_ELEMNAME_FUNCTION_STRING;
64  }
65
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   */
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