Characteristic

java.lang.Object
- com.saxonica.ee.trans.Characteristic<T>

Direct Known Subclasses:

AncestorCharacteristic, GeneralComparisonOperand, NumericComparisonOperand, TokenMatchOperand
```
public abstract class Characteristic<T>
extends java.lang.Object
```
A Characteristic represents a distinguishing feature of an item that may be used by several patterns in a rule chain, and which can usefully be evaluated once for all rules in the rule chain. Characteristics are evaluated in the course of evaluating preconditions, and their values may be used again when evaluating a different precondition. For example (a classic DITA use case), the tokenized value of an element's @class attribute is a characteristic that may be used by several preconditions that test for the presence of particular tokens in the value.

Constructor Summary

Constructors
Constructor Description

Characteristic()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`abstract T`	`evaluate(XPathContext context)`	Evaluate the value of this characteristic for the context item
`int`	`getSlotNumber()`	Get the slot number allocated to the value of this characteristic in the `RuleSearchState`
`void`	`setSlotNumber(int slotNumber)`	Allocate a slot number to this characteristic in the `RuleSearchState`

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

- Constructor Detail
  - Characteristic
```
public Characteristic()
```
- Method Detail
  - getSlotNumber
```
public final int getSlotNumber()
```
    Get the slot number allocated to the value of this characteristic in the RuleSearchState
    
    Returns:
    
    the allocated slot number
  - setSlotNumber
```
public final void setSlotNumber(int slotNumber)
```
    Allocate a slot number to this characteristic in the RuleSearchState
    
    Parameters:
    
    slotNumber - the slot number to be allocated
  - evaluate
```
public abstract T evaluate(XPathContext context)
                    throws XPathException
```
    Evaluate the value of this characteristic for the context item
    
    Parameters:
    
    context - the dynamic evaluation context; the context item is the item being matched
    
    Returns:
    
    the value of the characteristic
    
    Throws:
    
    XPathException - if evaluation of the characteristic fails