merryKingmas.rst

List Values

Unlike basic values, obtaining values from lists is slightly more involved, as multiple values are present. The main accessors for lists are

• getList(Function<Object, T>):List<T>
• getList(Function<Object, T>, List<T>):List<T>
• getList(TypeToken<T>):List<T>
• getList(TypeToken<T>, List<T>):List<T>.

For the purposes of this example, the following sample will be used be used:

{
    "modules" : {
        "blockCheats" : {
            "enabled" : true,
            "counters" : [1,2,3,4, "hello", 1.22]
        }
    }
}

Whereas for basic values you can simply do:

root.getNode("modules", "blockCheats", "enabled").getBoolean(false);

This is not possible for a list. Instead you can do something like this:

root.getNode("modules", "counters").getList(new Function<Object, Integer>(
    @Override
    public Integer apply(Object input) {
        if (input instanceof Integer) {
            return (Integer) input;
        }
        return null;
    }
)

The above code will return a list containing [1,2,3,4]. This can also shortened down using lambda expression:

root.getNode("modules").getList(input -> return input instanceof Integer ? (Integer) input : null);

However you may notice that running the same checks again and again may be inefficient and can potentially cause errors. Configurate provides a handy utility to handle that for you. The above example can be replaced by:

import ninja.leaping.configurate.Types;
root.getNode("modules","counters").getList(new Function<Object, Integer> {
    @Override
    public Integer apply(Object input) {
        return Types.asInt(input)
    }
}

Or simply:

import ninja.leaping.configurate.Types;
root.getNode("modules", "counters").getList(Types::asInt);