Package net.sf.saxon.expr

Class GlobalVariableReference.GlobalVariableReferenceElaborator

java.lang.Object

net.sf.saxon.expr.elab.Elaborator

net.sf.saxon.expr.elab.PullElaborator

net.sf.saxon.expr.GlobalVariableReference.GlobalVariableReferenceElaborator

All Implemented Interfaces:

SequenceEvaluator

Enclosing class:

GlobalVariableReference

public static class GlobalVariableReference.GlobalVariableReferenceElaborator
extends PullElaborator
implements SequenceEvaluator

Elaborator for a global variable reference, for example $globalVar.

Constructor Summary

Constructors

Constructor	Description
GlobalVariableReferenceElaborator()

Method Summary

Modifier and Type	Method	Description
SequenceEvaluator	eagerly()	Get a function that evaluates the underlying expression eagerly
ItemEvaluator	elaborateForItem()	Get a function that evaluates the underlying expression in the form of a Item.
PullEvaluator	elaborateForPull()	Get a function that evaluates the underlying expression in the form of a SequenceIterator
PushEvaluator	elaborateForPush()	Get a function that evaluates the underlying expression in push mode, by writing events to an Outputter
Sequence	evaluate(XPathContext context)	Evaluate a construct to produce a value (which might be a lazily evaluated Sequence)
SequenceEvaluator	lazily(boolean repeatable, boolean lazyEvaluationRequired)	Get a function that evaluates the underlying expression lazily

Methods inherited from class net.sf.saxon.expr.elab.PullElaborator

elaborateForBoolean, elaborateForUnicodeString

Methods inherited from class net.sf.saxon.expr.elab.Elaborator

elaborateForString, elaborateForUpdate, getConfiguration, getExpression, handleNullString, handleNullUnicodeString, handlePossiblyNullString, handlePossiblyNullUnicodeString, setExpression

Methods inherited from class java.lang.Object

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

Constructor Detail

GlobalVariableReferenceElaborator

public GlobalVariableReferenceElaborator()

Method Detail

evaluate

public Sequence evaluate(XPathContext context)
                  throws XPathException

Evaluate a construct to produce a value (which might be a lazily evaluated Sequence)

Specified by:

evaluate in interface SequenceEvaluator

Parameters:

context - the evaluation context

Returns:

a Sequence (not necessarily grounded)

Throws:

XPathException - if a dynamic error occurs during the evaluation.

eagerly

public SequenceEvaluator eagerly()

Description copied from class: Elaborator

Get a function that evaluates the underlying expression eagerly

Overrides:

eagerly in class PullElaborator

Returns:

an evaluator for the expression that returns a GroundedValue. The class SequenceEvaluator is declared to return a Sequence not a GroundedValue; we can't specialize it because it's a limitation of C# delegates, but the result can safely be cast to GroundedValue.

lazily

public SequenceEvaluator lazily(boolean repeatable,
                                boolean lazyEvaluationRequired)

Description copied from class: Elaborator

Get a function that evaluates the underlying expression lazily

Overrides:

lazily in class Elaborator

Parameters:

repeatable - true if the resulting Sequence must be usable repeatedly; false if it only needs to be used once

lazyEvaluationRequired - true if the expression MUST be evaluated lazily, for example to prevent spurious errors or side-effects if it has been lifted out of a loop

Returns:

an evaluator for the expression that returns a Sequence (which may be a lazy sequence)

elaborateForPull

public PullEvaluator elaborateForPull()

Description copied from class: Elaborator

Get a function that evaluates the underlying expression in the form of a SequenceIterator

Specified by:

elaborateForPull in class PullElaborator

Returns:

an evaluator for the expression that returns a SequenceIterator

elaborateForPush

public PushEvaluator elaborateForPush()

Description copied from class: Elaborator

Get a function that evaluates the underlying expression in push mode, by writing events to an Outputter

Overrides:

elaborateForPush in class PullElaborator

Returns:

an evaluator for the expression in push mode

elaborateForItem

public ItemEvaluator elaborateForItem()

Description copied from class: Elaborator

Get a function that evaluates the underlying expression in the form of a Item. This must only be called for expressions whose result has cardinality zero or one.

Overrides:

elaborateForItem in class PullElaborator

Returns:

an evaluator for the expression that returns an Item, or null to represent an empty sequence.