net.sf.saxon.expr
Class FunctionCall

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

All Implemented Interfaces:

Expression, java.io.Serializable

Direct Known Subclasses:

FunctionProxy, SystemFunction, UserFunctionCall

public abstract class FunctionCall

extends ComputedExpression

Abstract superclass for calls to system-defined and user-defined functions

See Also:

Serialized Form

Field Summary
protected  Expression[]	argument           The array of expressions representing the actual parameters to the function call

 

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

lineNumber, NO_ARGUMENTS, staticProperties

 

Constructor Summary

FunctionCall()

 

Method Summary
Expression	analyze(StaticContext env)           Type-check the expression.
protected  int	checkArgumentCount(int min, int max)           Check number of arguments.
protected abstract  void	checkArguments(StaticContext env)           Method supplied by each class of function to check arguments during parsing, when all the argument expressions have been read
void	display(int level, NamePool pool)           Diagnostic print of expression structure.
abstract  java.lang.String	getName()           Diagnostic print of expression structure
int	getNumberOfArguments()           Determine the number of actual arguments supplied in the function call
Expression[]	getSubExpressions()           Get the immediate subexpressions of this expression
Expression	preEvaluate(StaticContext env)           Pre-evaluate a function at compile time.
Expression	promote(PromotionOffer offer)           Promote this expression if possible
void	setArguments(Expression[] args)           Method called by the expression parser when all arguments have been supplied
Expression	simplify()           Simplify the function call.
protected  Expression	simplifyArguments()           Simplify the arguments of the function.

 

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

computeCardinality, computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getDependencies, getIntrinsicDependencies, getLineNumber, getSourceLocator, getSpecialProperties, iterate, markTailFunctionCalls, setLineNumber, typeError

 

Methods inherited from class java.lang.Object

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

 

Methods inherited from interface net.sf.saxon.expr.Expression

getItemType

 

Field Detail

argument

protected Expression[] argument

The array of expressions representing the actual parameters to the function call

FunctionCall

public FunctionCall()

getNumberOfArguments

public final int getNumberOfArguments()

Determine the number of actual arguments supplied in the function call

setArguments

public void setArguments(Expression[] args)

Method called by the expression parser when all arguments have been supplied

simplify

public Expression simplify()
                    throws XPathException

Simplify the function call. Default method is to simplify each of the supplied arguments and evaluate the function if all are now known.

Specified by:

simplify in interface Expression

Overrides:

simplify in class ComputedExpression

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

simplifyArguments

protected final Expression simplifyArguments()
                                      throws XPathException

Simplify the arguments of the function. Called from the simplify() method of each function.

Returns:

the result of simplifying the arguments of the expression

XPathException

analyze

public Expression analyze(StaticContext env)
                   throws XPathException

Type-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.

Parameters:

env - the static context of the expression

Returns:

the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

XPathException

preEvaluate

public Expression preEvaluate(StaticContext env)
                       throws XPathException

Pre-evaluate a function at compile time. Functions that do not allow pre-evaluation, or that need access to context information, can override this method.

XPathException

promote

public Expression promote(PromotionOffer offer)
                   throws XPathException

Promote this expression if possible

Specified by:

promote in interface Expression

Overrides:

promote in class ComputedExpression

Parameters:

offer - details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression

Returns:

if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression

Throws:

XPathException - if any error is detected

checkArguments

protected abstract void checkArguments(StaticContext env)
                                throws XPathException

Method supplied by each class of function to check arguments during parsing, when all the argument expressions have been read

XPathException

checkArgumentCount

protected int checkArgumentCount(int min,
                                 int max)
                          throws XPathException

Check number of arguments.
A convenience routine for use in subclasses.

Parameters:

min - the minimum number of arguments allowed

max - the maximum number of arguments allowed

Returns:

the actual number of arguments

Throws:

XPathException - if the number of arguments is out of range

getSubExpressions

public Expression[] getSubExpressions()

Get the immediate subexpressions of this expression

Specified by:

getSubExpressions in interface Expression

Overrides:

getSubExpressions in class ComputedExpression

Returns:

an array containing the sub-expressions of this expression

getName

public abstract java.lang.String getName()

Diagnostic print of expression structure

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

Parameters:

level - indentation level for this expression