IKeyField (Metaschema Core API 1.0.0-M1 API)

All Known Implementing Classes:

DefaultKeyField
```
public interface IKeyField
```
Represents a component of a key used in a key-based index.
A key field is targeted at a Metaschema field or flag data object's value. An optional pattern can be used to extract a portion of the value for use in generating an index key.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`Pattern`	`getPattern()`	A pattern to use to retrieve the value.
`MarkupMultiline`	`getRemarks()`	Any remarks about the key field as markup text.
`MetapathExpression`	`getTarget()`

- Method Detail
  - getTarget
```
@NonNull
MetapathExpression getTarget()
```
  - getPattern
```
@Nullable
Pattern getPattern()
```
    A pattern to use to retrieve the value. If non-null, the first capturing group is used to retrieve the value.
    
    Returns:
    
    a pattern to use to get the value or null if the full value is to be used
  - getRemarks
```
@Nullable
MarkupMultiline getRemarks()
```
    Any remarks about the key field as markup text.
    
    Returns:
    
    markup text or null if no text is provided