net.sf.saxon.expr
Class UserFunctionCall

java.lang.Object
  |
  +--net.sf.saxon.expr.ComputedExpression
        |
        +--net.sf.saxon.expr.FunctionCall
              |
              +--net.sf.saxon.expr.UserFunctionCall

All Implemented Interfaces:

Expression, java.io.Serializable

public class UserFunctionCall

extends FunctionCall

This class represents a call to a function defined in the stylesheet or query. It is used for all user-defined functions in XQuery, and for a limited class of user-defined functions in XSLT: those that can be reduced to the evaluation of a single expression.

See Also:

Serialized Form

Nested Class Summary
static class	UserFunctionCall.FunctionCallPackage           Inner class used to wrap up the set of actual arguments to a tail-recursive call of the containing function.

 

Field Summary

 

Fields inherited from class net.sf.saxon.expr.FunctionCall

argument

 

Fields inherited from class net.sf.saxon.expr.ComputedExpression

lineNumber, NO_ARGUMENTS, staticProperties

 

Constructor Summary

UserFunctionCall()

 

Method Summary
void	checkArguments(StaticContext env)           Method called during the type checking phase
int	computeCardinality()           Determine the cardinality of the result
void	display(int level, NamePool pool)           Diagnostic print of expression structure.
Item	evaluateItem(XPathContext c)           Call the function, returning the value as an item.
int	getFingerprint()           Get the fingerprint representing the name of the function
ItemType	getItemType()           Determine the data type of the expression, if possible
java.lang.String	getName()           Get the name of the function.
SequenceIterator	iterate(XPathContext c)           Call the function, returning an iterator over the results.
boolean	markTailFunctionCalls()           Mark tail-recursive calls on stylesheet functions.
Expression	preEvaluate(StaticContext env)           Pre-evaluate a function at compile time.
void	setFingerprint(int fingerprint)           Set the fingerprint representing the name of the function
void	setFunction(FunctionSignature sourceFunction, CallableFunction compiledFunction)           Create the reference to the function to be called, and validate for consistency
void	setStaticType(SequenceType type)           Set the static type
Expression	simplify()           Simplify the function call

 

Methods inherited from class net.sf.saxon.expr.FunctionCall

analyze, checkArgumentCount, getNumberOfArguments, getSubExpressions, promote, setArguments, simplifyArguments

 

Methods inherited from class net.sf.saxon.expr.ComputedExpression

computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getDependencies, getIntrinsicDependencies, getLineNumber, getSourceLocator, getSpecialProperties, setLineNumber, typeError

 

Methods inherited from class java.lang.Object

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

 

Constructor Detail

UserFunctionCall

public UserFunctionCall()

setFingerprint

public void setFingerprint(int fingerprint)

Set the fingerprint representing the name of the function

getFingerprint

public int getFingerprint()

Get the fingerprint representing the name of the function

setStaticType

public void setStaticType(SequenceType type)

Set the static type

setFunction

public void setFunction(FunctionSignature sourceFunction,
                        CallableFunction compiledFunction)
                 throws XPathException

Create the reference to the function to be called, and validate for consistency

XPathException

getName

public java.lang.String getName()

Get the name of the function. Used for diagnostic purposes only.

Specified by:

getName in class FunctionCall

Returns:

the name of the function, as used in XSL expressions

checkArguments

public void checkArguments(StaticContext env)
                    throws XPathException

Method called during the type checking phase

Specified by:

checkArguments in class FunctionCall

XPathException

preEvaluate

public Expression preEvaluate(StaticContext env)

Pre-evaluate a function at compile time. This version of the method suppresses early evaluation by doing nothing.

Overrides:

preEvaluate in class FunctionCall

getItemType

public ItemType getItemType()

Determine the data type of the expression, if possible

Returns:

Type.ITEM (meaning not known in advance)

computeCardinality

public int computeCardinality()

Determine the cardinality of the result

Specified by:

computeCardinality in class ComputedExpression

simplify

public Expression simplify()
                    throws XPathException

Simplify the function call

Specified by:

simplify in interface Expression

Overrides:

simplify in class FunctionCall

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

markTailFunctionCalls

public boolean markTailFunctionCalls()

Mark tail-recursive calls on stylesheet functions. For most expressions, this does nothing.

Overrides:

markTailFunctionCalls in class ComputedExpression

Returns:

true if a tail recursive call was found and if this call accounts for the whole of the value.

evaluateItem

public Item evaluateItem(XPathContext c)
                  throws XPathException

Call the function, returning the value as an item. This method will be used only when the cardinality is zero or one. If the function is tail recursive, it returns an Object representing the arguments to the next (recursive) call, which is specially handled by the code in FunctionInstr.

Specified by:

evaluateItem in interface Expression

Overrides:

evaluateItem in class ComputedExpression

Parameters:

c - The context in which the expression is to be evaluated

Returns:

the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence

Throws:

XPathException - if any dynamic error occurs evaluating the expression

iterate

public SequenceIterator iterate(XPathContext c)
                         throws XPathException

Call the function, returning an iterator over the results. (But if the function is tail recursive, it returns an iterator over the arguments of the recursive call, which is specially handled by the code in FunctionInstr)

Specified by:

iterate in interface Expression

Overrides:

iterate in class ComputedExpression

Parameters:

c - supplies the context for evaluation

Returns:

a SequenceIterator that can be used to iterate over the result of the expression

Throws:

XPathException - if any dynamic error occurs evaluating the expression

display

public void display(int level,
                    NamePool pool)

Description copied from interface: Expression

Diagnostic print of expression structure. The expression is written to the System.err output stream

Specified by:

display in interface Expression

Overrides:

display in class FunctionCall

Parameters:

level - indentation level for this expression