# Triggering Stop Actions

This guide shows how a feature can request a controlled stop or restart through OMS.

The example extends `HelloWorldFeature` with a command that triggers a stop request.

***

### Overview

Features do not stop the server directly.

Instead, they emit an OMS action event describing:

* the requested operation
* the reason for the request

OMS then processes the request and executes the appropriate stop flow.

***

### 1. Define a stop reason

A stop request must include a `StopReason`.

Minimal example:

```kotlin
object HelloWorldStopReason : StopReason {
    override val addonId: String = HelloWorldMod.MOD_ID
    override val name: String = "manual"
}
```

***

### Recommended pattern

To avoid repeating `addonId`, define a base type:

```kotlin
interface HelloWorldStopReason : StopReason {
    override val addonId: String
        get() = HelloWorldMod.MOD_ID
}
```

Then define reasons:

```kotlin
object HelloWorldManualStop : HelloWorldStopReason {
    override val name: String = "manual"
}
```

***

### Localization

Each stop reason automatically generates a localization key:

```json
<addonId>.stop_reason.<name>
```

Example:

```json
hello_world.stop_reason.manual
```

You can define messages in your language file:

```json
{
  "hello_world.stop_reason.manual": "Server stopped by HelloWorld feature"
}
```

***

### 2. Trigger the stop request

To request a stop, emit an OMS action event:

```kotlin
class HelloWorldStopCommand(
    private val feature: HelloWorldFeature
) : OMSCommandEntry() {

    override fun init(): ArgumentBuilder<CommandSourceStack, *> {
        return Commands.literal("stop")
            .executes { ctx ->
                val server = ctx.source.server

                MinecraftForge.EVENT_BUS.post(
                    OMSActions.StopRequestedEvent(
                        server = server,
                        reason = HelloWorldManualStop
                    )
                )
                1
            }
    }
}
```

***

### 3. Attach the command to the feature

```kotlin
class HelloWorldFeature(
    configProvider: ConfigProvider<CHelloWorldFeature>
) : OmsFeature<CHelloWorldFeature>(configProvider) {

    override val additionalCommands = listOf(
        // ...
        HelloWorldStopCommand(this)
    )

}
```

***

### 4. Use the command

After startup:

```
/oms feature hello_world stop
```

This sends a stop request to OMS.

***

### 5. Example from OMS

OMS itself defines stop reasons using the same pattern:

```kotlin
object ScheduledStop : OmsStopReason {
    override val name: String = "scheduled"
}
```

With localization:

```json
{
  "oms.stop_reason.scheduled": "Server stopping as scheduled"
}
```

***

### Notes

* Features must not stop the server directly
* All stop requests go through OMS action events
* Stop reasons are stable identifiers
* Localization is based on `messageId`
* OMS controls the actual shutdown flow


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