Parameter injection

[lilearnhardt]

Is your feature request related to a problem?

When writing commands, you have to acquire context about your sender (for example, plugin User object, player's team, or current minigame). By default, you have to write code in your command executors, and that may produce many boilerplate.

Describe the solution you'd like.

Implement a parameter injection feature: for a specific type of arguments in your command methods, you register a provider that will get required value and pass it to the executor, or null if not present. May also add a way to cancel command execution (similar to requirements), for example when required value is absent.

Describe alternatives you've considered.

None

Other

No response

[Strokkur424]

Example usage (discussed in #general on PaperMC):

void execute(CommandSender sender,
             @CustomArg(GamePlayerArg.class) GamePlayer player) {
    /* ... */ 
}

@ArgumentConstructor
private void GamePlayerArg gamePlayerArg() {
    return new GamePlayerArg(this.manager, this.plugin);
}