Beginning Java Data Structures and Algorithms

Safe Enqueuing in an Array

We need to write a safe enqueue() method that will fail when the queue is full. 

Steps for completion:

1. Modify the enqueue and dequeue methods shown in the preceding code so that the enqueue returns a Boolean value which is false when the queue is full and cannot accept further elements.
2. Implement the method signatures as follows:

public boolean enqueueSafe(V item)public Optional<V> dequeueSafe()  

3. The following Snippet 2.26 provides an implementation of the enqueueSafe() method, returning a Boolean value when the queue is full:

private boolean full = false;public boolean enqueueSafe(V item) {  if (!full) {    array[tailPtr] = item;    tailPtr = (tailPtr + 1) % array.length;    this.full = tailPtr == headPtr; return true; ...