net.sf.saxon.expr.parser

Class Evaluator.LazySequence

java.lang.Object

net.sf.saxon.expr.parser.Evaluator

net.sf.saxon.expr.parser.Evaluator.LazySequence

Enclosing class:

Evaluator

public static final class Evaluator.LazySequence
extends Evaluator

An evaluator for arguments that in general return a sequence, where the sequence is evaluated lazily on first use. This is appropriate when calling a function which might not use the value, or might not use all of it. It returns a LazySequence, which can only be read once, so this is only suitable for use when calling a function that can be trusted to read the argument once only.

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.saxon.expr.parser.Evaluator

Evaluator.EagerSequence, Evaluator.EmptySequenceEvaluator, Evaluator.LazySequence, Evaluator.LazyTail, Evaluator.Literal, Evaluator.MakeIndexedVariable, Evaluator.MemoClosureEvaluator, Evaluator.OptionalItem, Evaluator.Process, Evaluator.SharedAppend, Evaluator.SingleItem, Evaluator.SingletonClosure, Evaluator.StreamingArgument, Evaluator.SuppliedParameter, Evaluator.Variable

Field Summary

Fields

Modifier and Type	Field and Description
static Evaluator.LazySequence	INSTANCE

Constructor Summary

Constructors

Constructor and Description
LazySequence()

Method Summary

Modifier and Type	Method and Description
Sequence	evaluate(Expression expr, XPathContext context) Evaluate an expression to return a sequence
int	getCode() Get the integer code for the evaluator

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final Evaluator.LazySequence INSTANCE

Constructor Detail

LazySequence

public LazySequence()

Method Detail

getCode

public int getCode()

Description copied from class: Evaluator

Get the integer code for the evaluator

Specified by:

getCode in class Evaluator

Returns:

the integer code for the evaluator

evaluate

public Sequence evaluate(Expression expr,
                         XPathContext context)
                  throws XPathException

Description copied from class: Evaluator

Evaluate an expression to return a sequence

Specified by:

evaluate in class Evaluator

Parameters:

expr - the expression to be evaluated

context - the dynamic context for evaluation

Returns:

the result of the evaluation

Throws:

XPathException - if any dynamic error occurs during the evaluation