net.sf.saxon.expr.parser

Class Evaluator

java.lang.Object

net.sf.saxon.expr.parser.Evaluator

Direct Known Subclasses:

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

public abstract class Evaluator
extends java.lang.Object

An Evaluator evaluates an expression to return a sequence

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Evaluator.EagerSequence An evaluator for arguments that in general return a sequence, where the sequence is evaluated eagerly.
static class	Evaluator.EmptySequenceEvaluator An evaluator that always returns the empty sequence
static class	Evaluator.LazySequence An evaluator for arguments that in general return a sequence, where the sequence is evaluated lazily on first use.
static class	Evaluator.LazyTail An evaluator for arguments that in general return a sequence, where the sequence is evaluated lazily on first use.
static class	Evaluator.Literal An evaluator for arguments supplied as a literal
static class	Evaluator.MakeIndexedVariable An evaluator for an expression that makes use of an indexed variable
static class	Evaluator.MemoClosureEvaluator An evaluator for arguments that in general return a sequence, where the sequence is evaluated lazily on first use, and where the value might be needed more than once.
static class	Evaluator.OptionalItem A (default) evaluator for arguments supplied as an expression that will return either a singleton item, or an empty sequence
static class	Evaluator.Process A push-mode evaluator for an expression
static class	Evaluator.SharedAppend An evaluator for "shared append" expressions: used when the argument to a function is a block potentially containing a recursive call.
static class	Evaluator.SingleItem A (default) evaluator for arguments supplied as an expression that will always return a singleton item
static class	Evaluator.SingletonClosure An evaluator for arguments that in general return a sequence, where the sequence is evaluated lazily on first use, and where the value might be needed more than once.
static class	Evaluator.StreamingArgument An evaluator for the first (streamed) argument of a streamable function call.
static class	Evaluator.SuppliedParameter An evaluator for a reference to an external parameter value
static class	Evaluator.Variable An evaluator for arguments supplied as a variable reference

Constructor Summary

Constructors

Constructor and Description
Evaluator()

Method Summary

Modifier and Type	Method and Description
abstract Sequence	evaluate(Expression expr, XPathContext context) Evaluate an expression to return a sequence
abstract 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

Constructor Detail

Evaluator

public Evaluator()

Method Detail

getCode

public abstract int getCode()

Get the integer code for the evaluator

Returns:

the integer code for the evaluator

evaluate

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

Evaluate an expression to return a sequence

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