net.sf.saxon.expr.instruct

Class LocalParam

java.lang.Object

net.sf.saxon.expr.instruct.GeneralVariable

net.sf.saxon.expr.instruct.LocalParam

All Implemented Interfaces:

SourceLocator, Binding

public final class LocalParam
extends GeneralVariable

The compiled form of an xsl:param element within a template in an XSLT stylesheet.

The xsl:param element in XSLT has mandatory attribute name and optional attribute select. It can also be specified as required="yes" or required="no".

This is used only for parameters to XSLT templates. For function calls, the caller of the function places supplied arguments onto the callee's stackframe and the callee does not need to do anything. Global parameters (XQuery external variables) are handled using GlobalParam.

The LocalParam class is also used to represent parameters with the saxon:iterate instruction

Field Summary

Fields inherited from class net.sf.saxon.expr.instruct.GeneralVariable

evaluationMode, referenceCount, slotNumber, variableQName

Constructor Summary

Constructors

Constructor and Description
LocalParam()

Method Summary

Methods

Modifier and Type	Method and Description
Sequence	evaluateVariable(XPathContext c) Evaluate the variable
void	explain(ExpressionPresenter out) Diagnostic print of expression structure.
Expression	getConversion() Get the conversion expression
int	getConversionEvaluationMode()
int	getInstructionNameCode() Get the name of this instruction for diagnostic and tracing purposes
IntegerValue[]	getIntegerBoundsForVariable() If the variable is bound to an integer, get the minimum and maximum possible values.
int	getParameterId() Get the parameter id, which is essentially an alias for the parameter name, unique within a stylesheet
Iterator<Expression>	iterateSubExpressions() Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)
TailCall	processLeavingTail(XPathContext context) Process the local parameter declaration
boolean	replaceSubExpression(Expression original, Expression replacement) Replace one subexpression by a replacement subexpression
void	setConversion(Expression convertor) Define a conversion that is to be applied to the supplied parameter value.
void	setParameterId(int id) Allocate a number which is essentially an alias for the parameter name, unique within a stylesheet

Methods inherited from class net.sf.saxon.expr.instruct.GeneralVariable

addReference, checkAgainstRequiredType, computeEvaluationMode, copy, getCardinality, getColumnNumber, getContainer, getEvaluationMode, getExecutable, getLineNumber, getLocalSlotNumber, getLocationId, getLocationProvider, getPublicId, getRequiredType, getSelectExpression, getSelectValue, getSlotNumber, getSystemId, getSystemId, getVariableQName, init, isAssignable, isGlobal, isImplicitlyRequiredParam, isRequiredParam, isTunnelParam, optimize, setContainer, setImplicitlyRequiredParam, setLocationId, setReferenceCount, setRequiredParam, setRequiredType, setSelectExpression, setSlotNumber, setTunnel, setVariableQName, simplify, typeCheck

Methods inherited from class java.lang.Object

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

Constructor Detail

LocalParam

public LocalParam()

Method Detail

setParameterId

public void setParameterId(int id)

Allocate a number which is essentially an alias for the parameter name, unique within a stylesheet

Parameters:

id - the parameter id

getParameterId

public int getParameterId()

Get the parameter id, which is essentially an alias for the parameter name, unique within a stylesheet

Returns:

the parameter id

setConversion

public void setConversion(Expression convertor)

Define a conversion that is to be applied to the supplied parameter value.

Parameters:

convertor - The expression to be applied. This performs type checking, and the basic conversions implied by function calling rules, for example numeric promotion, atomization, and conversion of untyped atomic values to a required type. The conversion uses the actual parameter value as input, referencing it using a VariableReference. The argument can be null to indicate that no conversion is required.

getConversion

public Expression getConversion()

Get the conversion expression

Returns:

the expression used to convert the value to the required type, or null if there is none

getConversionEvaluationMode

public int getConversionEvaluationMode()

getInstructionNameCode

public int getInstructionNameCode()

Get the name of this instruction for diagnostic and tracing purposes

Overrides:

getInstructionNameCode in class GeneralVariable

Returns:

the name of this instruction, as a name pool name code

iterateSubExpressions

public Iterator<Expression> iterateSubExpressions()

Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)

Overrides:

iterateSubExpressions in class GeneralVariable

Returns:

an iterator over all the contained expressions (in practice, the select expression)

replaceSubExpression

public boolean replaceSubExpression(Expression original,
                           Expression replacement)

Replace one subexpression by a replacement subexpression

Overrides:

replaceSubExpression in class GeneralVariable

Parameters:

original - the original subexpression

replacement - the replacement subexpression

Returns:

true if the original subexpression is found

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws XPathException

Process the local parameter declaration

Parameters:

context - the dynamic context

Returns:

either null if processing is complete, or a tailcall if one is left outstanding

Throws:

XPathException - if a dynamic error occurs in the evaluation

getIntegerBoundsForVariable

public IntegerValue[] getIntegerBoundsForVariable()

If the variable is bound to an integer, get the minimum and maximum possible values. Return null if unknown or not applicable

Specified by:

getIntegerBoundsForVariable in interface Binding

Overrides:

getIntegerBoundsForVariable in class GeneralVariable

Returns:

a pair of integers containing the minimum and maximum values for the integer value; or null if the value is not an integer or the range is unknown

evaluateVariable

public Sequence evaluateVariable(XPathContext c)

Evaluate the variable

Parameters:

c - the XPath dynamic evaluation context

Returns:

the result of evaluating the variable

explain

public void explain(ExpressionPresenter out)

Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

Overrides:

explain in class GeneralVariable

Parameters:

out - the object used to present the output