CODEWITHSUNDEEP
javareactive-programmingproject-reactor
Christof Hullaert
Christof Hullaert

Reputation: 311

Reduce GroupedFlux in reactor

I have one flux with distinct object types inside it that I want group elements by type and then reduce each group.

here is a trivial code to do this.

    Flux<Item> item=Flux.just(new Item("item1"), new Item("item2"));
    Flux<Item2> item2=Flux.just(new Item2(4.0f), new Item2(2.0f));

    Flux<Object> objects=Mono.empty().concatWith(item).concatWith(item2);       
    Flux<GroupedFlux<Object>> groups=objects.groupBy(value -> value.getClass());

How can I reduce each flow by type?enter code here

Upvotes: 1

Views: 3466

Answers (1)

Christof Hullaert
Christof Hullaert

Reputation: 311

I found the solution on the gitter. Thanks to @simonbasle and @osi for reactiviy.

https://gitter.im/reactor/reactor

The key was the method flatMap and use the key to discrimine values.

groups.flatMap(gf -> {
        if(gf.key()==Item.class) {
            return gf.reduce(new Item(""), (a, b) -> {
                return new Item(a.getValue()+((Item)b).getValue());
            });
        }
        else if(gf.key()==Item2.class) {
            return gf.reduce(new Item2(0.0f), (a, b) -> {
                return new Item2(a.getValueF()+((Item2)b).getValueF());
            });
        }
        throw new IllegalArgumentException("unknown key: "+gf.key());
    });

Upvotes: 4

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