Interfaces and Inner Classes - Absolute Java - page 755

the InventoryItem class—your code does not have to ensure that they are
unique. Next, modify the class so that it implements the Comparable inter-
face. The compareTo() method should compare the uniqueItemID 's; e.g., the
InventoryItem with item ID 5 is less than the InventoryItem with ID 10.
Test your class by creating an array of sample InventoryItem 's and sort them
using a sorting method that takes as input an array of type Comparable .
3. Listed next is a code skeleton for an interface called Enumeration and a class
called NameCollection . Enumeration provides an interface to sequentially iter-
ate through some type of collection. In this case, the collection will be the class
NameCollection that simply stores a collection of names using an array of strings.
interface Enumeration
{
// Returns true if another element in the collection exists
public boolean hasNext();
// Returns the next element in the collection as an Object
public Object getNext();
}
/**
* NameCollection implements a collection of names using
* a simple array.
*/
class NameCollection
{
String[] names;
/**
* The list of names is initialized from outside
* and passed in as an array of strings
*/
NameCollection(String[] names)
{
this.names = names;
}
/**
* getEnumeration should return an instance of a class that
implements
* the Enumeration interface where hasNext() and getNext()
* correspond to data stored within the names array.
*/
Enumeration getEnumeration ()
{
// Complete code here using an inner class
}
}