org.apache.xpath.functions
Class Function
java.lang.Object
|
+--org.apache.xpath.Expression
|
+--org.apache.xpath.functions.Function
- Direct Known Subclasses:
- FuncCurrent, FuncExtFunction, FuncFalse, FuncLast, FuncPosition, FunctionOneArg, FuncTrue
- public abstract class Function
- extends Expression
This is a superclass of all XPath functions. This allows two
ways for the class to be called. One method is that the
super class processes the arguments and hands the results to
the derived class, the other method is that the derived
class may process it's own arguments, which is faster since
the arguments don't have to be added to an array, but causes
a larger code footprint.
- See Also:
- Serialized Form
- Usage:
- **For advanced use only**
Methods inherited from class org.apache.xpath.Expression |
asIterator,
asIteratorRaw,
asNode,
assertion,
bool,
canTraverseOutsideSubtree,
error,
execute,
execute,
execute,
executeCharsToContentHandler,
exprAddChild,
exprGetChild,
exprGetNumChildren,
exprGetParent,
exprSetParent,
fixupVariables,
getColumnNumber,
getExpressionOwner,
getLineNumber,
getPublicId,
getSystemId,
isNodesetExpr,
isStableNumber,
num,
warn,
xstr |
Methods inherited from class java.lang.Object |
equals,
getClass,
hashCode,
notify,
notifyAll,
toString,
wait,
wait,
wait |
Function
public 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.
checkNumberArgs
public void checkNumberArgs(int argNum)
throws WrongNumberArgsException
- Check that the number of arguments passed to this function is correct.
This method is meant to be overloaded by derived classes, to check for
the number of arguments for a specific function type. This method is
called by the compiler for static number of arguments checking.
- Parameters:
argNum
- The number of arguments that is being passed to the function.- Throws:
- WrongNumberArgsException -
execute
public XObject execute(XPathContext xctxt)
throws TransformerException
- Execute an XPath function object. The function must return
a valid object.
- Parameters:
xctxt
- The execution current context.- Returns:
- A valid XObject.
- Throws:
- TransformerException -
- Overrides:
- execute in class Expression
callArgVisitors
public void callArgVisitors(XPathVisitor visitor)
- Call the visitors for the function arguments.
callVisitors
public void callVisitors(ExpressionOwner owner,
XPathVisitor visitor)
- See Also:
XPathVisitable.callVisitors(ExpressionOwner, XPathVisitor)
deepEquals
public boolean deepEquals(Expression expr)
- Overrides:
- deepEquals in class Expression
- See Also:
Expression.deepEquals(Expression)
postCompileStep
public void postCompileStep(Compiler compiler)
- This function is currently only being used by Position()
and Last(). See respective functions for more detail.
Copyright © 2006 Apache XML Project. All Rights Reserved.