net.sf.saxon.expr
Class Assignation

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.Assignation

All Implemented Interfaces:

Serializable, SourceLocator, Binding, Container, EvaluableItem, SequenceIterable, InstructionInfoProvider

Direct Known Subclasses:

ForExpression, LetExpression, QuantifiedExpression

public abstract class Assignation
extends Expression
implements Binding

Assignation is an abstract superclass for the kinds of expression that declare range variables: for, some, and every.

See Also:

Serialized Form

Field Summary

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

Assignation()

Method Summary

ValueRepresentation	evaluateVariable(XPathContext context) Get the value of the range variable
Expression	getAction() Get the action expression
int	getLocalSlotNumber() If this is a local variable held on the local stack frame, return the corresponding slot number.
int	getRequiredSlots() Get the number of slots required.
Expression	getSequence() Get the "sequence" expression - the one to which the variable is bound
RangeVariableDeclaration	getVariableDeclaration() Get the variable declaration
int	getVariableFingerprint()
String	getVariableName() Get the display name of the range variable, for diagnostics only
int	getVariableNameCode()
boolean	isAssignable() Test whether it is permitted to assign to the variable using the saxon:assign extension element.
boolean	isGlobal() Indicate whether the binding is local or global.
Iterator	iterateSubExpressions() Get the immediate subexpressions of this expression
Expression	promote(PromotionOffer offer) Promote this expression if possible
boolean	replaceSubExpression(Expression original, Expression replacement) Replace one subexpression by a replacement subexpression
void	setAction(Expression action) Add the "return" or "satisfies" expression, and fix up all references to the range variable that occur within that expression
void	setSequence(Expression sequence) Set the "sequence" expression - the one to which the variable is bound
void	setSlotNumber(int nr) Set the slot number for the range variable
void	setVariableDeclaration(RangeVariableDeclaration decl) Set the reference to the variable declaration
Expression	simplify(StaticContext env) Simplify the expression
void	suppressValidation(int validationMode) Suppress validation on contained element constructors, on the grounds that the parent element is already performing validation.

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

adoptChildExpression, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, display, doPromotion, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getColumnNumber, getContainingProcedure, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getItemType, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, optimize, process, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, typeCheck

Methods inherited from class java.lang.Object

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

Constructor Detail

Assignation

public Assignation()

Method Detail

setVariableDeclaration

public void setVariableDeclaration(RangeVariableDeclaration decl)

Set the reference to the variable declaration

getVariableDeclaration

public RangeVariableDeclaration getVariableDeclaration()

Get the variable declaration

setAction

public void setAction(Expression action)

Add the "return" or "satisfies" expression, and fix up all references to the range variable that occur within that expression

Parameters:

action - the expression that occurs after the "return" keyword of a "for" expression, the "satisfies" keyword of "some/every", or the ":=" operator of a "let" expression.

This method must be called after calling setVariableDeclaration()

isGlobal

public final boolean isGlobal()

Indicate whether the binding is local or global. A global binding is one that has a fixed value for the life of a query or transformation; any other binding is local.

Specified by:

isGlobal in interface Binding

isAssignable

public final boolean isAssignable()

Test whether it is permitted to assign to the variable using the saxon:assign extension element. This will only be for an XSLT global variable where the extra attribute saxon:assignable="yes" is present.

Specified by:

isAssignable in interface Binding

getLocalSlotNumber

public int getLocalSlotNumber()

If this is a local variable held on the local stack frame, return the corresponding slot number. In other cases, return -1.

Specified by:

getLocalSlotNumber in interface Binding

getAction

public Expression getAction()

Get the action expression

setSequence

public void setSequence(Expression sequence)

Set the "sequence" expression - the one to which the variable is bound

getSequence

public Expression getSequence()

Get the "sequence" expression - the one to which the variable is bound

setSlotNumber

public void setSlotNumber(int nr)

Set the slot number for the range variable

getRequiredSlots

public int getRequiredSlots()

Get the number of slots required. Normally 1, except for a FOR expression with an AT clause, where it is 2.

simplify

public Expression simplify(StaticContext env)
                    throws XPathException

Simplify the expression

Overrides:

simplify in class Expression

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

promote

public Expression promote(PromotionOffer offer)
                   throws XPathException

Promote this expression if possible

Overrides:

promote in class Expression

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

suppressValidation

public void suppressValidation(int validationMode)

Suppress validation on contained element constructors, on the grounds that the parent element is already performing validation. The default implementation does nothing.

Overrides:

suppressValidation in class Expression

iterateSubExpressions

public Iterator iterateSubExpressions()

Get the immediate subexpressions of this expression

Overrides:

iterateSubExpressions in class Expression

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

Specified by:

replaceSubExpression in interface Container

Overrides:

replaceSubExpression in class Expression

Parameters:

original - the original subexpression

replacement - the replacement subexpression

Returns:

true if the original subexpression is found

getVariableNameCode

public int getVariableNameCode()

getVariableFingerprint

public int getVariableFingerprint()

getVariableName

public String getVariableName()

Get the display name of the range variable, for diagnostics only

evaluateVariable

public ValueRepresentation evaluateVariable(XPathContext context)
                                     throws XPathException

Get the value of the range variable

Specified by:

evaluateVariable in interface Binding

Throws:

XPathException