org.apache.xpath.functions

Class FuncExtFunction

Implemented Interfaces:
Serializable, ExpressionNode, SourceLocator, XPathVisitable

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

Constructor Summary

FuncExtFunction(String namespace, String extensionName, 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(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.
String
getFunctionName()
Return the name of the extension function.
Object
getMethodKey()
Return the method key of the extension function.
String
getNamespace()
Return the namespace of the extension function.
void
setArg(Expression arg, int argNum)
Set an argument expression for a function.

Methods inherited from class org.apache.xpath.functions.Function

callArgVisitors, callVisitors, checkNumberArgs, deepEquals, execute, postCompileStep, setArg

Methods inherited from class org.apache.xpath.Expression

asIterator, asIteratorRaw, asNode, assertion, bool, canTraverseOutsideSubtree, deepEquals, error, execute, execute, execute, execute, executeCharsToContentHandler, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, fixupVariables, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isNodesetExpr, isStableNumber, num, warn, xstr

Constructor Details

FuncExtFunction

public FuncExtFunction(String namespace,
                       String extensionName,
                       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 Details

callArgVisitors

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

checkNumberArgs

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

execute

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

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.
Specified by:
exprSetParent in interface ExpressionNode
Overrides:
exprSetParent in interface Expression
Parameters:
n - The parent node

fixupVariables

public void fixupVariables(Vector vars,
                           int globalsSize)
This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
Overrides:
fixupVariables in interface Expression
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

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.

getFunctionName

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

getMethodKey

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

getNamespace

public String getNamespace()
Return the namespace of the extension function.
Returns:
The namespace of the extension 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.
Overrides:
setArg in interface Function
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.

Copyright B) 2004 Apache XML Project. All Rights Reserved.