Package net.sf.saxon.expr.elab

Class SharedAppendEvaluator

java.lang.Object

net.sf.saxon.expr.elab.SharedAppendEvaluator

All Implemented Interfaces:

SequenceEvaluator

public class SharedAppendEvaluator
extends Object
implements SequenceEvaluator

Evaluator for expressions that are evaluated in "shared append" mode. This mode is used when the optimizer establishes that a sequence is being built incrementally, typically via a sequence of recursive function calls. The sequence itself is implemented as a ZenoSequence to make incremental append (at either end) efficient, without copying the entirety of the existing sequence.

Constructor Summary

Constructors

Constructor	Description
SharedAppendEvaluator(Block expr)

Method Summary

Modifier and Type	Method	Description
Sequence	evaluate(XPathContext context)	Evaluate a construct to produce a value (which might be a lazily evaluated Sequence)

Methods inherited from class java.lang.Object

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

Constructor Details

SharedAppendEvaluator

public SharedAppendEvaluator(Block expr)

Method Details

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.