Processor

The Processor is something of a chameleon in Flow; it may act as both a Subscriber and a Publisher.

There are several different reasons for adding an interface such as the Processor. One reason may be that you have a stream of data that you do not fully trust. Imagine an asynchronous flow of data from a server, where data is delivered over a UDP connection that lacks promises of delivery; this data will eventually be corrupted and you need to handle that. A simple way would be to inject a filter of some kind between the publisher and subscriber. This is where a Processor excels.

Another reason for using a Processor could be to separate a polymorphic data stream between different subscribers so that alternative actions may be taken based on the data type.

Exercise 2: Using a Processor to Convert a Stream of Strings to Numbers

In this exercise, we will first build a Publisher that periodically publishes a string from a text file. Then, we will use a scheduler to...