net.sf.saxon.instruct
Class Assign

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

All Implemented Interfaces:

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

public class Assign
extends GeneralVariable
implements BindingReference

saxon:assign element in stylesheet. The saxon:assign element has mandatory attribute name and optional attribute expr. It also allows xsl:extension-element-prefixes etc.

See Also:

Serialized Form

Field Summary

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

evaluationMode, referenceCount, slotNumber, variableQName

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

EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties

Constructor Summary

Assign()

Method Summary

ValueRepresentation	evaluateVariable(XPathContext context) Evaluate the variable (method exists only to satisfy the interface)
void	explain(ExpressionPresenter out) Diagnostic print of expression structure.
void	fixup(Binding binding) Fix up this binding reference to a binding
int	getInstructionNameCode() Get the name of this instruction for diagnostic and tracing purposes
int	getIntrinsicDependencies() Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.
TailCall	processLeavingTail(XPathContext context) ProcessLeavingTail: called to do the real work of this instruction.
Expression	promote(PromotionOffer offer, Expression parent) Offer promotion for this subexpression.
void	setStaticType(SequenceType type, Value constantValue, int properties) Fix up the static type of this variable reference; optionally, supply a constant value for the variable.

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

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

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

assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, createsNewNodes, dynamicError, evaluateAsString, getConstructType, getImplementationMethod, getSourceLocator, isXSLT, process

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

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getColumnNumber, getColumnNumber, getContainer, getDependencies, getExecutable, getHostLanguage, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, resetLocalStaticProperties, setContainer, 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

Assign

public Assign()

Method Detail

setStaticType

public void setStaticType(SequenceType type,
                          Value constantValue,
                          int properties)

Description copied from interface: BindingReference

Fix up the static type of this variable reference; optionally, supply a constant value for the variable. Also supplies other static properties of the expression to which the variable is bound, for example whether it is an ordered node-set.

Specified by:

setStaticType in interface BindingReference

fixup

public void fixup(Binding binding)

Description copied from interface: BindingReference

Fix up this binding reference to a binding

Specified by:

fixup in interface BindingReference

getIntrinsicDependencies

public int getIntrinsicDependencies()

Description copied from class: Expression

Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".

Overrides:

getIntrinsicDependencies in class Expression

Returns:

a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

promote

public Expression promote(PromotionOffer offer,
                          Expression parent)
                   throws XPathException

Offer promotion for this subexpression. This needs careful handling in the case of saxon:assign

Overrides:

promote in class Instruction

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

parent -

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

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

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws XPathException

Description copied from class: Instruction

ProcessLeavingTail: called to do the real work of this instruction. This method must be implemented in each subclass. The results of the instruction are written to the current Receiver, which can be obtained via the Controller.

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 context)
                                     throws XPathException

Evaluate the variable (method exists only to satisfy the interface)

Specified by:

evaluateVariable in interface Binding

Parameters:

context - the XPath dynamic evaluation context

Returns:

the result of evaluating the variable

Throws:

XPathException

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