Anchoring and acking

We have talked about DAG that is created for the execution of a Storm topology. Now when you are designing your topologies to cater to reliability, there are two items that needs to be added to Storm:

• Whenever a new link, that is, a new stream is being added to the DAG, it is called anchoring
• When the tuple is processed in entirety, it is called acking

When Storm knows these preceding facts, then during the processing of tuples it can gauge them and accordingly fail or acknowledge the tuples depending upon whether they are completely processed or not.

Let's take a look at the following WordCount topology bolts to understand the Storm API anchoring and acking better:

• SplitSentenceBolt: The purpose of this bolt was to split the sentence into different words and emit it. Now let's examine the output declarer and the execute methods of this bolt in detail (specially the highlighted sections) as shown in the following code:

    public void execute(Tuple tuple) {
       ...