Understanding orMap

• Look at the first two variants of the orMap method (the recursively defined variant and the variant that uses the while loop. Identify the four parts (BASE-VALUE, Termination/Continuation PREDICATE, UPDATE, and ADVANCE) in each of them.

  Look also at the tests in the Examples class.

• After you understand how the while loop works, design two variants of the method that produces a new ArrayList that contains all elements of the original list that satisfy the given Predicate predicate.

  Test the methods by producing all red balloons or all small balloons.

• Design and test two variants of the andMap method that determines whether all elements of a given list satisfy the given Predicate predicate.

  Test the methods by checking whether a list contains all red balloons or all small balloons.

Converting while loops into for loops

Repeat all the parts of the previous task with the remaining two variants of the orMap — namely the one that uses the for loop with the Traversal and the one that uses counted for loop.

For Each

Optionally, you may look at the ultimate abstraction of these traversals shown in the ForEach class.

1. Read the tests for the ’for’ variant of the compute method of the ForEach class shown in the Examples class. Make sure you understand how they work. Design additional tests for each of the three compute methods.