You have seen so far that in Cascading, we can create building blocks of different sizes, functionality, and granularity, and we can reuse and rearrange these blocks to build very agile, customized applications.

You have seen operations, subassemblies, and flows—each of them are a building block of sorts that we define in large grains to create our application. We can go further now and arrange flows into cascades. You may recall we defined cascades in Chapter 2, Cascading Basics in Detail, and have been intermittently referring to them throughout this book.

Let's revisit the definition of a cascade. A cascade is a collection of flows. Separate and individual flows can be placed together in a defined sequence and execution graph, and they are executed as a single process that is referred to as cascade. A cascade has an additional feature, that if one flow depends on the output of another (that is, the source of one pipe is the sink of another), the dependent flow will not be...