> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom field

> Configuration reference for `CustomFieldDescription` and `AnonymousCustomFieldDescription`, Java objects that define a named or anonymous column calculator for use in a Channel.

<Note>
  A Custom Field cannot be defined via configuration properties but can be referenced by name.
</Note>

### Java configuration

`CustomFieldDescription` or `AnonymousCustomFieldDescription` Java object can be used for configuration in Java. The Object is used in the configuration of a [Channel](/configuration/channel).

Additionally,
a `CustomFieldDescription` Spring Bean can be resolved in configuration properties of a channel by name under
`custom-fields` as well as used in Java by name using the `NamedEntityResolverService`.

##### CustomFieldDescription

| Parameter               | Required | Type                       | Description                                                        |
| ----------------------- | :------: | -------------------------- | ------------------------------------------------------------------ |
| name                    |     Y    | `String`                   | Name of the Column Calculator.                                     |
| columnCalculatorFactory |     Y    | `IColumnCalculatorFactory` | Function which accepts DlcScope and produces an IColumnCalculator. |

##### AnonymousCustomFieldDescription

| Parameter               | Required | Type                       | Description                                                        |
| ----------------------- | :------: | -------------------------- | ------------------------------------------------------------------ |
| columnCalculatorFactory |     Y    | `IColumnCalculatorFactory` | Function which accepts DlcScope and produces an IColumnCalculator. |