Package org.apache.xpath.functions
Class Function
java.lang.Object
org.apache.xpath.Expression
org.apache.xpath.functions.Function
- All Implemented Interfaces:
Serializable
,SourceLocator
,ExpressionNode
,XPathVisitable
- Direct Known Subclasses:
FuncCurrent
,FuncExtFunction
,FuncFalse
,FuncLast
,FuncPosition
,FunctionOneArg
,FuncTrue
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:
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
callArgVisitors
(XPathVisitor visitor) Call the visitors for the function arguments.void
callVisitors
(ExpressionOwner owner, XPathVisitor visitor) This will traverse the heararchy, calling the visitor for each member.void
checkNumberArgs
(int argNum) Check that the number of arguments passed to this function is correct.boolean
deepEquals
(Expression expr) Compare this object with another object and see if they are equal, include the sub heararchy.execute
(XPathContext xctxt) Execute an XPath function object.void
postCompileStep
(Compiler compiler) This function is currently only being used by Position() and Last().void
setArg
(Expression arg, int argNum) Set an argument expression for a function.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
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Constructor Details
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Function
public Function()
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Method Details
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setArg
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.
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checkNumberArgs
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
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execute
Execute an XPath function object. The function must return a valid object.- Specified by:
execute
in classExpression
- Parameters:
xctxt
- The execution current context.- Returns:
- A valid XObject.
- Throws:
TransformerException
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callArgVisitors
Call the visitors for the function arguments. -
callVisitors
Description copied from interface:XPathVisitable
This will traverse the heararchy, calling the visitor for each member. If the called visitor method returns false, the subtree should not be called.- Parameters:
owner
- The owner of the visitor, where that path may be rewritten if needed.visitor
- The visitor whose appropriate method will be called.- See Also:
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deepEquals
Description copied from class:Expression
Compare this object with another object and see if they are equal, include the sub heararchy.- Specified by:
deepEquals
in classExpression
- Parameters:
expr
- Another expression object.- Returns:
- true if this objects class and the expr object's class are the same, and the data contained within both objects are considered equal.
- See Also:
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postCompileStep
This function is currently only being used by Position() and Last(). See respective functions for more detail.
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