java - Field Groping in Apache Storm - Looking for Motivational Examples

Question

To understand the field-grouping of Apache Storm, I thought of creating a single spout which will emit few fixed lines to a bolt. The bolt (let's call it emitter) in turn will emit words along with a tag (in Storm's parlance a Field) say "WORD". In the next layer, I wanted to set up three bolts (call them counters) - expecting each of the counters to receive same words whenever the spout produce them. But I have never expected that the same words would be given to all of the counters- which is surprisingly what is happening with below topology.

TopologyBuilder builder = new TopologyBuilder();
builder.setSpout("reader",new ReaderSpout());
builder.setBolt("emitter", new EmitterBolt()).shuffleGrouping("reader");
        
builder.setBolt("counter1", new CounterBolt(),1)
            .fieldsGrouping("emitter", new Fields("WORD"));
builder.setBolt("counter2", new CounterBolt(),1)
        .fieldsGrouping("emitter", new Fields("WORD"));
builder.setBolt("counter3", new CounterBolt(),1)
        .fieldsGrouping("emitter", new Fields("WORD"));

Any help will be much appreciated. My primary objective to understand the usefulness of 'fieldsGrouping', and soft objective is to have a two counter-bolts one receiving words staring with vowel and other bolts receiving words starting with consonants.

question from:https://stackoverflow.com/questions/65944382/field-groping-in-apache-storm-looking-for-motivational-examples

Answer 1

Waitting for answers