Kafka流，将输出分支到多个主题

Question

In my DSL based transformation, I have a stream-->branch, where in I want branched output redirected to multiple topics. Current branch.to() method accepts only a String . Is there any simple option with stream.branch where I can route the result to multiple topics. With a consumer, I can subscribe to multiple topics by providing an array of string as topics.

My problem requires me to take multiple actions if particular predicate satisfies a query.

I tried with stream.branch[index].to(string) , but this is not sufficient for my requirement. I am looking for something like stream.branch[index].to(string array of topics) or stream.branch[index].to(string) .

I expect the branch.to method with multiple topics or is there any alternate way to achieve the same with streams?

adding sample code.Removed actual variable names.

My Predicates

    Predicate <String, MyDomainObject> Predicate1 = new Predicate<String, MyDomainObject>() {
        @Override
        public boolean test(String key, MyDomainObject domObj) {
            boolean result = false;
    if condition on domObj
            return result;
        }
    };
    Predicate <String, MyDomainObject> Predicate2 = new Predicate<String, MyDomainObject>() {
        @Override
        public boolean test(String key, MyDomainObject domObj) {
            boolean result = false;
    if condition on domObj
            return result;
        }
    };

    KStream <String, MyDomainObject>[] branches= myStream.branch(
            Predicate1, Predicate2
    );


// here I need your suggestions.

// this is my current implementation
branches[0].to(singleTopic),
            Produced.with(Serdes.String(), Serdes.serdeFrom(inSer, deSer)));

// I want to send notification to multiple topics. something like below

branches[0].to(topicList),
            Produced.with(Serdes.String(), Serdes.serdeFrom(inSer, deSer)));

Answer 1

If you know to which topics you want to send the data, you can do the following:

branches[0].to("first-topic");
branches[0].to("second-topic");
// etc.