org.apache.xpath.functions

Class FuncExtFunction

java.lang.Object

org.apache.xpath.Expression

org.apache.xpath.functions.Function

org.apache.xpath.functions.FuncExtFunction

All Implemented Interfaces:

Serializable, SourceLocator, ExpressionNode, 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

Constructors

Constructor and Description
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

Modifier and Type	Method and Description
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.
protected void	reportWrongNumberArgs() Constructs and throws a WrongNumberArgException with the appropriate message for this function object.
void	setArg(Expression arg, int argNum) Set an argument expression for a function.
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, isSameClass, isStableNumber, num, warn, xstr

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

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 Detail

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.

Specified by:

fixupVariables in class 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

getNamespace

public String getNamespace()

Return the namespace of the extension function.

Returns:

The namespace of the extension function.

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.

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.

Overrides:

execute in class Function

Parameters:

xctxt - The current execution context.

Returns:

A valid XObject.

Throws:

TransformerException

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 class 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.

checkNumberArgs

public void checkNumberArgs(int argNum)
                     throws WrongNumberArgsException

Check that the number of arguments passed to this function is correct.

Overrides:

checkNumberArgs in class Function

Parameters:

argNum - The number of arguments that is being passed to the function.

Throws:

WrongNumberArgsException

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.

Specified by:

exprSetParent in interface ExpressionNode

Overrides:

exprSetParent in class Expression

Parameters:

n - The parent node

reportWrongNumberArgs

protected void reportWrongNumberArgs()
                              throws WrongNumberArgsException

Constructs and throws a WrongNumberArgException with the appropriate message for this function object. This class supports an arbitrary number of arguments, so this method must never be called.

Overrides:

reportWrongNumberArgs in class Function

Throws:

WrongNumberArgsException

toString

public String toString()

Return the name of the extesion function in string format

Overrides:

toString in class Object