Evaluator.OptionalItem

java.lang.Object
- net.sf.saxon.expr.parser.Evaluator
- - net.sf.saxon.expr.parser.Evaluator.OptionalItem

Enclosing class:

Evaluator
```
public static final class Evaluator.OptionalItem
extends Evaluator
```
A (default) evaluator for arguments supplied as an expression that will return either a singleton item, or an empty sequence

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 Description

static Evaluator.OptionalItem INSTANCE

Constructor Summary

Constructors
Constructor Description

OptionalItem()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	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.OptionalItem INSTANCE
```
- Constructor Detail
  - OptionalItem
```
public OptionalItem()
```
- 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