org.apache.xpath.functions
Class FuncExtFunction

java.lang.Object
  |
  +--org.apache.xpath.Expression
        |
        +--org.apache.xpath.functions.Function
              |
              +--org.apache.xpath.functions.FuncExtFunction

public class FuncExtFunction
extends Function

An object of this class represents an extension call expression. When the expression executes, it calls ExtensionsTable#extFunction, and then converts the result to the appropriate XObject.

See Also:
Serialized Form
Usage:
**For advanced use only**

Constructor Summary
FuncExtFunction(java.lang.String namespace, java.lang.String extensionName, java.lang.Object methodKey)
          Create a new FuncExtFunction based on the qualified name of the extension, and a unique method key.
 
Method Summary
 void callArgVisitors(XPathVisitor visitor)
          Call the visitors for the function arguments.
 void checkNumberArgs(int argNum)
          Check that the number of arguments passed to this function is correct.
 XObject execute(XPathContext xctxt)
          Execute the function.
 void exprSetParent(ExpressionNode n)
          Set the parent node.
 void fixupVariables(java.util.Vector vars, int globalsSize)
          This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
 Expression getArg(int n)
          Return the nth argument passed to the extension function.
 int getArgCount()
          Return the number of arguments that were passed into this extension function.
 java.lang.String getFunctionName()
          Return the name of the extension function.
 java.lang.Object getMethodKey()
          Return the method key of the extension function.
 java.lang.String getNamespace()
          Return the namespace of the extension function.
 void setArg(Expression arg, int argNum)
          Set an argument expression for a function.
 java.lang.String toString()
          Return the name of the extesion function in string format
 
Methods inherited from class org.apache.xpath.functions.Function
callVisitors, deepEquals, postCompileStep
 
Methods inherited from class org.apache.xpath.Expression
asIterator, asIteratorRaw, asNode, assertion, bool, canTraverseOutsideSubtree, error, execute, execute, execute, executeCharsToContentHandler, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isNodesetExpr, isStableNumber, num, warn, xstr
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

FuncExtFunction

public FuncExtFunction(java.lang.String namespace,
                       java.lang.String extensionName,
                       java.lang.Object methodKey)
Create a new FuncExtFunction based on the qualified name of the extension, and a unique method key.
Parameters:
namespace - The namespace for the extension function, which should not normally be null or empty.
extensionName - The local name of the extension.
methodKey - Unique method key, which is passed to ExtensionsTable#extFunction in order to allow caching of the method.
Method Detail

fixupVariables

public void fixupVariables(java.util.Vector vars,
                           int globalsSize)
This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
Parameters:
vars - List of QNames that correspond to variables. This list should be searched backwards for the first qualified name that corresponds to the variable reference qname. The position of the QName in the vector from the start of the vector will be its position in the stack frame (but variables above the globalsTop value will need to be offset to the current stack frame). NEEDSDOC @param globalsSize
Overrides:
fixupVariables in class Expression

getNamespace

public java.lang.String getNamespace()
Return the namespace of the extension function.
Returns:
The namespace of the extension function.

getFunctionName

public java.lang.String getFunctionName()
Return the name of the extension function.
Returns:
The name of the extension function.

getMethodKey

public java.lang.Object getMethodKey()
Return the method key of the extension function.
Returns:
The method key of the extension function.

getArg

public Expression getArg(int n)
Return the nth argument passed to the extension function.
Parameters:
n - The argument number index.
Returns:
The Expression object at the given index.

getArgCount

public int getArgCount()
Return the number of arguments that were passed into this extension function.
Returns:
The number of arguments.

execute

public XObject execute(XPathContext xctxt)
                throws TransformerException
Execute the function. The function must return a valid object.
Parameters:
xctxt - The current execution context.
Returns:
A valid XObject.
Throws:
TransformerException -  
Overrides:
execute in class Function

setArg

public void setArg(Expression arg,
                   int argNum)
            throws WrongNumberArgsException
Set an argument expression for a function. This method is called by the XPath compiler.
Parameters:
arg - non-null expression that represents the argument.
argNum - The argument number index.
Throws:
WrongNumberArgsException - If the argNum parameter is beyond what is specified for this function.
Overrides:
setArg in class Function

checkNumberArgs

public void checkNumberArgs(int argNum)
                     throws WrongNumberArgsException
Check that the number of arguments passed to this function is correct.
Parameters:
argNum - The number of arguments that is being passed to the function.
Throws:
WrongNumberArgsException -  
Overrides:
checkNumberArgs in class Function

callArgVisitors

public void callArgVisitors(XPathVisitor visitor)
Call the visitors for the function arguments.
Overrides:
callArgVisitors in class Function

exprSetParent

public void exprSetParent(ExpressionNode n)
Set the parent node. For an extension function, we also need to set the parent node for all argument expressions.
Parameters:
n - The parent node
Overrides:
exprSetParent in class Expression

toString

public java.lang.String toString()
Return the name of the extesion function in string format
Overrides:
toString in class java.lang.Object


Copyright 2006 Apache XML Project. All Rights Reserved.