FirstItemExpression.FirstItemExprElaborator

java.lang.Object
- net.sf.saxon.expr.elab.Elaborator
- - net.sf.saxon.expr.elab.ItemElaborator
  - - net.sf.saxon.expr.FirstItemExpression.FirstItemExprElaborator

Enclosing class:

FirstItemExpression
```
public static class FirstItemExpression.FirstItemExprElaborator
extends ItemElaborator
```
An elaborator for a "first-item" expression, typically written as X[1] or as head(X).

Constructor Summary

Constructors
Constructor Description

FirstItemExprElaborator()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`ItemEvaluator`	`elaborateForItem()`	Get a function that evaluates the underlying expression in the form of a `Item`.

Methods inherited from class net.sf.saxon.expr.elab.ItemElaborator
eagerly, elaborateForBoolean, elaborateForPull, elaborateForPush, elaborateForUnicodeString

Methods inherited from class net.sf.saxon.expr.elab.Elaborator
elaborateForString, elaborateForUpdate, getConfiguration, getExpression, handleNullString, handleNullUnicodeString, handlePossiblyNullString, handlePossiblyNullUnicodeString, lazily, setExpression

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - FirstItemExprElaborator
```
public FirstItemExprElaborator()
```
- Method Detail
  - 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.
    
    Specified by:
    
    elaborateForItem in class ItemElaborator
    
    Returns:
    
    an evaluator for the expression that returns an Item, or null to represent an empty sequence.