Creating a `Context`

Plugins Plugin Development
1

I was busy implementing the Economy API when I noticed Set<Context>, but how do I create a global context?

What is the point of REMOTE_IP_KEY, LOCAL_HOST_KEY, LOCAL_IP_KEY and LOCAL_PORT_KEY?
Contexts are poorly explained in the Javadocs.

2

A global context is just an empty Set<Context>.

A word on the different keys: You don’t have to implement all existing keys, and you can also add your own custom keys.

For example a context key “time” with possible values “day” and “night” (people can not access their bank account at night, something like that).

To do that, just implement a TimeContextCalculator:

public class TimeContextCalculator extends ContextCalculator<Player> {

    public void accumulateContexts(Player subject, Set<Context> accumulator) {
        Context timeContext = new Context("time", isInDaytimeDimension(subject) ? "day" : "night");
        accumulator.add(timeContext);
    }

    public boolean matches(Context context, Player subject) {
        if(context.getKey().equals("time")) {
            return (isInDaytimeDimension(subject) == context.getValue().equals("day"));
        }
        return false;
    }

    private boolean isInDaytimeDimension(Player player) {
        return ...;
    }
}

That’s also how you would implement the default context keys.

3

That cleared things up.

When you know what contexts are for, they sound very powerful for imposing any given condition.

4

Economies can also exploit these for per world or per region economies.