net.sf.saxon.expr.instruct
Class LocalParam

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.instruct.Instruction
          net.sf.saxon.expr.instruct.GeneralVariable
              net.sf.saxon.expr.instruct.LocalParam

All Implemented Interfaces:

Serializable, SourceLocator, LocationProvider, SaxonLocator, Binding, EvaluableItem, TailCallReturner, SequenceIterable, InstructionInfo, Locator

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

See Also:

Serialized Form

Field Summary

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

evaluationMode, referenceCount, slotNumber, variableQName

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

EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, PUSH_SELECTION, staticProperties, WATCH_METHOD

Constructor Summary

LocalParam()

Method Summary

ValueRepresentation	evaluateVariable(XPathContext c) Evaluate the variable
void	explain(ExpressionPresenter out) Diagnostic print of expression structure.
int	getInstructionNameCode() Get the name of this instruction for diagnostic and tracing purposes
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

copy, evaluateItem, getCardinality, getEvaluationMode, getItemType, getLocalSlotNumber, getRequiredType, getSelectExpression, getSelectValue, getSlotNumber, getVariableQName, init, isAssignable, isGlobal, isImplicitlyRequiredParam, isRequiredParam, isTunnelParam, iterate, optimize, promoteInst, setAssignable, setImplicitlyRequiredParam, setReferenceCount, setRequiredParam, setRequiredType, setSelectExpression, setSlotNumber, setTunnel, setVariableQName, simplify, typeCheck

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

assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, createsNewNodes, dynamicError, evaluateAsString, getConstructType, getExpressionName, getImplementationMethod, getInstructionName, getIteratorFromProcessMethod, getSourceLocator, isXSLT, process, promote

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

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getColumnNumber, getColumnNumber, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toString, typeError

Methods inherited from class java.lang.Object

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

Methods inherited from interface javax.xml.transform.SourceLocator

getColumnNumber, getLineNumber, getPublicId, getSystemId

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.

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 containing the sub-expressions of this 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

Specified by:

processLeavingTail in interface TailCallReturner

Specified by:

processLeavingTail in class Instruction

Parameters:

context - The dynamic context of the transformation, giving access to the current node, the current variables, etc.

Returns:

null if the instruction has completed execution; or a TailCall indicating a function call or template call that is delegated to the caller, to be made after the stack has been unwound so as to save stack space.

Throws:

XPathException

evaluateVariable

public ValueRepresentation 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 expression presenter used to display the structure