Exploring Advanced Language Features - Beginning Java 7 - page 266

Note Javaallowsrawtypestobeintermixedwithgenerictypestosupportthevast
amount of legacy code that was written prior to the arrival of generics. However, the
compileroutputsawarningmessagewheneveritencountersarawtypeinsourcecode.
Declaring and Using Your Own Generic Types
It is not difficult to declare your own generic types. In addition to specifying a formal
typeparameterlist,yourgenerictypespecifiesitstypeparameter(s)throughoutitsim-
plementation. For example, Listing 3-52 declares a Queue<E> generic type.
Listing 3-52. Declaring and using a Queue<E> generic type
class Queue<E>
{
private E[] elements;
private int head, tail;
@SuppressWarnings("unchecked")
Queue(int size)
{
if (size < 2)
throw new IllegalArgumentException(""+size);
elements = (E[]) new Object[size];
head = 0;
tail = 0;
}
void insert(E element) throws QueueFullException
{
if (isFull())
throw new QueueFullException();
elements[tail] = element;
tail = (tail+1)%elements.length;
}
E remove() throws QueueEmptyException
{
if (isEmpty())
throw new QueueEmptyException();
E element = elements[head];