Implement the DiskScanner class, including the amendments you considered to this class in exercise 2 of the last chapter.

Exercise 2

In exercise 1 of the last chapter you considered the specification of a composite Sensor type. Implement this as a class in Java, then write a tester program to initialize and display a set of sensors as described in the same question.

Exercise 1

Why did the implementation of the Block class in section 10.2 include an invariant, when no invariant was associated with the composite Block type in the VDM specification?