1 /*
2  * reserved comment block
3  * DO NOT REMOVE OR ALTER!
4  */
5 /*
6  * Copyright 1999-2004 The Apache Software Foundation.
7  *
8  * Licensed under the Apache License, Version 2.0 (the "License");
9  * you may not use this file except in compliance with the License.
10  * You may obtain a copy of the License at
11  *
12  *     http://www.apache.org/licenses/LICENSE-2.0
13  *
14  * Unless required by applicable law or agreed to in writing, software
15  * distributed under the License is distributed on an "AS IS" BASIS,
16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17  * See the License for the specific language governing permissions and
18  * limitations under the License.
19  */
20 /*
21  * $Id: ExpressionContext.java,v 1.2.4.1 2005/09/10 19:34:03 jeffsuttor Exp $
22  */
23 package com.sun.org.apache.xalan.internal.extensions;
24 
25 import javax.xml.transform.ErrorListener;
26 
27 import com.sun.org.apache.xpath.internal.objects.XObject;
28 import org.w3c.dom.Node;
29 import org.w3c.dom.traversal.NodeIterator;
30 
31 /**
32  * An object that implements this interface can supply
33  * information about the current XPath expression context.
34  */
35 public interface ExpressionContext
36 {
37 
38   /**
39    * Get the current context node.
40    * @return The current context node.
41    */
getContextNode()42   public Node getContextNode();
43 
44   /**
45    * Get the current context node list.
46    * @return An iterator for the current context list, as
47    * defined in XSLT.
48    */
getContextNodes()49   public NodeIterator getContextNodes();
50 
51   /**
52    * Get the error listener.
53    * @return The registered error listener.
54    */
getErrorListener()55   public ErrorListener getErrorListener();
56 
57   /**
58    * Get the value of a node as a number.
59    * @param n Node to be converted to a number.  May be null.
60    * @return value of n as a number.
61    */
toNumber(Node n)62   public double toNumber(Node n);
63 
64   /**
65    * Get the value of a node as a string.
66    * @param n Node to be converted to a string.  May be null.
67    * @return value of n as a string, or an empty string if n is null.
68    */
toString(Node n)69   public String toString(Node n);
70 
71   /**
72    * Get a variable based on it's qualified name.
73    *
74    * @param qname The qualified name of the variable.
75    *
76    * @return The evaluated value of the variable.
77    *
78    * @throws javax.xml.transform.TransformerException
79    */
getVariableOrParam(com.sun.org.apache.xml.internal.utils.QName qname)80   public XObject getVariableOrParam(com.sun.org.apache.xml.internal.utils.QName qname)
81             throws javax.xml.transform.TransformerException;
82 
83   /**
84    * Get the XPathContext that owns this ExpressionContext.
85    *
86    * Note: exslt:function requires the XPathContext to access
87    * the variable stack and TransformerImpl.
88    *
89    * @return The current XPathContext.
90    * @throws javax.xml.transform.TransformerException
91    */
getXPathContext()92   public com.sun.org.apache.xpath.internal.XPathContext getXPathContext()
93             throws javax.xml.transform.TransformerException;
94 
95 }
96