ann.util.Queue

Queue.java presents a Queue of linked nodes built "from scratch" whose integrity cannot be violated (unlike Java's Queue class). Uses ann.util.SinglyLinkedNode to store its values.

public Queue()

Default constructor

Postcondition: Empty stack is constructed.

public boolean isEmpty()

Check if queue is empty

Return: true if queue is empty, and false otherwise

public Object first()

First operation

Return: Object at the front of the queue; null if queue is empty

public void add(Object obj)

Add operation

Receive: Object value

Postcondition: value has been added at the back of the queue

public Object remove()

Remove operation

Return: Object at the front of the queue; null if queue is empty

Postcondition: Value at the front of the queue has been removed.

public int getSize()

Size accessor

Return: number of elements in the queue

public void clear()

Clear mutator

Postcondition: All values have been removed from the queue.

public String toString()

String conversion for output purposes

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