# Jmix Create Enum

> Create a Jmix enum for entity attributes with stable database ids and localization.

- Skill: `jmix-framework/jmix-create-enum` (Agent Skill)
- Install (CLI): `npx skillmds@latest add jmix-framework/jmix-create-enum`
- Raw SKILL.md: https://api.skillmd.com/api/skills/jmix-framework/jmix-create-enum/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: jmix-framework (https://skillmd.com/u/jmix-framework)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/jmix-framework/jmix-create-enum

---


# Create Jmix Enum

Use this skill when an entity attribute has a fixed set of values.

## Steps

0. **Look for an existing enum convention in the project first.** Many codebases
   have a shared base interface that every enum implements, often with a default
   `getId()` — see "Joining an existing enum family" below. Match it instead of
   introducing a second scheme.
1. Create the enum in the `entity` package.
2. Implement `io.jmix.core.metamodel.datatype.EnumClass<T>`.
3. Use stable database ids, not display labels.
4. Add a typed `fromId()` method annotated with `@Nullable` from `org.jspecify.annotations`.
5. Store the enum id type in the entity field.
6. Add getter/setter conversion in the entity.
7. Add Liquibase column matching the id type.
8. Add enum message keys in all locale files — see `jmix-add-i18n-keys` for the `<package>/<EnumClass>.<CONSTANT>` key shape (e.g. `com.company.app.entity/TransactionType.INCOME`), NOT an all-dots `FQCN.CONSTANT` form.

## Enum Template

```java
import io.jmix.core.metamodel.datatype.EnumClass;
import org.jspecify.annotations.Nullable;

public enum TransactionType implements EnumClass<String> {
    INCOME("INCOME"),
    OUTCOME("OUTCOME");

    private final String id;

    TransactionType(String id) {
        this.id = id;
    }

    @Override
    public String getId() {
        return id;
    }

    @Nullable
    public static TransactionType fromId(String id) {
        for (TransactionType value : TransactionType.values()) {
            if (value.getId().equals(id)) {
                return value;
            }
        }
        return null;
    }
}
```

A constant may carry further constructor arguments and accessors beside the stable id. They are invisible to the
metamodel, so extra state needs no message key and appears in no fetch plan. Only the **stable id** is ever persisted —
never a second field, however convenient its value looks as a column.

## Entity Mapping

```java
@Column(name = "TYPE", nullable = false, length = 50)
private String type;

public TransactionType getType() {
    return type == null ? null : TransactionType.fromId(type);
}

public void setType(TransactionType type) {
    this.type = type == null ? null : type.getId();
}
```

## Stable-id type-chain

Keep one consistent id type across `EnumClass<T>`, `getId()`/`fromId()`, the entity field, and the Liquibase column (e.g. all `String`/`VARCHAR`). A mismatch compiles cleanly but silently corrupts load/save. Each literal id must be a hardcoded stable value, never a display label or `ordinal()`/`name()`.

When binding an enum attribute in a view, use `<comboBox>` (its `Range` is an enumeration) — not `entityComboBox`, which is for entity associations.

## Joining an existing enum family

Before writing the template below, grep for a base interface the project's enums
already implement:

```bash
grep -rn "implements .*EnumClass" src/main/java --include='*.java' | head
```

If one exists and its `getId()` returns `name()`, **match it**. The `.name()`
prohibition below is about not introducing that scheme into a project that has no
id convention yet — it is not a reason to make one new enum the only member of a
family with a different id scheme.

## Forbidden

- `io.jmix.core.EnumClass`.
- Raw `EnumClass` without a type parameter.
- Storing display labels as ids.
- `ordinal()` persistence, or introducing `.name()` ids into a project that has no enum id convention yet (an established project-wide convention is matched, not split — see above).
- Missing enum message keys.