GraphQLHandler 7.0.0 API

All Implemented Interfaces:
```
public final class GraphQLHandler

                    
```
Serves GraphQL subscriptions over the graphql-transport-ws protocol (https://github.com/enisdenjo/graphql-ws/blob/master/PROTOCOL.md).
The message types come from graphql-kotlin, but they are annotated for Jackson 3 and fastjson2, so incoming frames are dispatched on the type field by hand rather than deserialized into the sealed GraphQLSubscriptionMessage. That keeps the plugin working with whatever JsonMapper the application has configured.
Note on subprotocol negotiation: Javalin exposes no API for it, and the Jetty handshake underneath echoes back whichever subprotocol the client requested first, without checking it. A graphql-transport-ws client therefore connects correctly, but a client asking for something this handler does not speak — the legacy graphql-ws subprotocol, say — is told yes and then receives messages it cannot understand. Rejecting those needs a Javalin change.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description

Field Summary

Fields
Modifier and Type	Field	Description

Constructor Summary

Constructors
Constructor	Description
`GraphQLHandler(GraphQLPluginBuilder graphQLBuilder)`

Enum Constant Summary

Enum Constants
Enum Constant	Description

Method Summary

Modifier and Type	Method	Description
`final Unit`	`onMessage(WsMessageContext ctx)`
`final Unit`	`onClose(WsCloseContext ctx)`	Cancels everything still running for a connection that went away.
`final Unit`	`shutdown()`	Cancels every subscription still running and releases the scope.

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

- Constructor Detail
  - GraphQLHandler
```
GraphQLHandler(GraphQLPluginBuilder graphQLBuilder)
```
- Method Detail
  - onMessage
```
 final Unit onMessage(WsMessageContext ctx)
```
  - onClose
```
 final Unit onClose(WsCloseContext ctx)
```
    Cancels everything still running for a connection that went away.
  - shutdown
```
 final Unit shutdown()
```
    Cancels every subscription still running and releases the scope. Called once, when the server is stopping. The scope is not reusable afterwards, which is fine: a Javalin instance cannot be restarted.