JAVA PROGRAMMING 3

Write a method mergeQueue to be outside ArrayQueue class and accepts three parameters q1,q2 and q3 of type ArrayQueue. The method merges q1 and q2 into q3 by copying one element from q1 then q2 and so on. The method returns false, if any of q1 or q2 is empty, otherwise, it returns true.

Before Run:

front rear

q1: 3 7 9 5

q2: 4 8 2

q3:

After Run:

Front rear

q1: 3 7 9 5

front rear

q2: 4 8 2

q3: 3 4 7 8 9 2 5

public static boolean mergeQueue(ArrayQueue q1, ArrayQueue q2, ArrayQueue q3)

{ } Please ONLY DO THE METHOD I WILL GIVE U THE QUEUE IMPLEMENTATION

class ArrayQueue

{

// Data Fields

private E[] theData; // Array to hold the data.

private int front; // Index of the front of the queue.

private int rear; // Index of the rear of the queue.

private int size; // Current size (actual number of elements)

// of the queue.

private int capacity; // Current capacity of the queue.

private static final int DEFAULT_CAPACITY = 10;

// Default capacity of the queue.

// Constructors

/**

* Construct a queue with the default initial capacity.

*/

public ArrayQueue()

{

this(DEFAULT_CAPACITY);

}

/**

* Construct a queue with the specified initial capacity.

* @param initCapacity The initial capacity

*/

@SuppressWarnings("unchecked")

public ArrayQueue(int initCapacity)

{ if(initCapacity <= 0)

capacity = DEFAULT_CAPACITY;

else

capacity = initCapacity;

theData = (E[]) new Object[capacity];

front = 0;

rear = capacity - 1;

size = 0;

}

/** Copy constructor: Construct a new queue as copy of the existing

* queue passed as parameter.

* @param other The original queue

* copy is made in this object

*/

public ArrayQueue(ArrayQueue other)

{

capacity = other.capacity;

size = other.size;

front = other.front;

rear = other.rear;

theData = (E[]) new Object[capacity];

int index = front;

for (int i = 0; i < size; i++) {

theData[index]= other.theData[index];

index = (index + 1) % capacity;

}

}

// Public Methods

/**

* Return true, if the queue is empty

* @return True if the queue is empty

*/

public boolean isEmpty()

{

return (size == 0);

}

/**

* Inserts an item at the rear of the queue.

* @post item is added to the rear of the queue.

* @param item The element to add

* @return true (always successful)

*/

public boolean offer(E item)

{

if (size == capacity) {

reallocate();

}

size++;

rear = (rear + 1) % capacity;

theData[rear] = item;

return true;

}

/**

* Returns the item at the front of the queue without removing it.

* @return The item at the front of the queue, if successful;

* return null if the queue is empty

*/

public E peek()

{

if (size == 0) {

return null;

}

else {

return theData[front];

}

}

/**

* Removes the entry at the front of the queue and returns it,

* if the queue is not empty.

* @return The item removed if queue is not empty, else return null.

*/

public E poll()

{

if (size == 0) {

return null;

}

E result = theData[front];

front = (front + 1) % capacity;

size--;

return result;

}

/**

* Returns an iterator to the elements in the queue

* @return an iterator to the elements in the queue

*/

public Iterator iterator()

{

return new Iter();

}

// Private Method

/**

* Double the capacity and reallocate the data.

* @pre The array is filled to capacity.

* @post The capacity is doubled and the first half of the

* expanded array is filled with data.

*/

@SuppressWarnings("unchecked")

private void reallocate()

{

int newCapacity = 2 * capacity;

E[] newData = (E[]) new Object[newCapacity];

int j = front;

for (int i = 0; i < size; i++) {

newData[i] = theData[j];

j = (j + 1) % capacity;

}

front = 0;

rear = size - 1;

capacity = newCapacity;

theData = newData;

}

public int size() { return size;}

/** Inner class to implement the Iterator interface. */

private class Iter implements Iterator

{

// Data Fields

private int index; // Index of next element

private int count; // Count of elements accessed so far

// Methods

// Constructor

/**

* Initializes the Iter object to reference the first queue element.

*/

public Iter()

{

index = front;

count = 0;

}

/**

* @return true, if there are more elements in the queue to access.

*/

public boolean hasNext()

{

return (count < size);

}

/**

* Returns the next element in the queue.

* @pre index references the next element to access.

* @post index and count are incremented.

* @return The element with subscript index

*/

public E next()

{

if (!hasNext()) {

throw new NoSuchElementException();

}

E returnValue = theData[index];

index = (index + 1) % capacity;

count++;

return returnValue;

}

public void remove()

{

throw new UnsupportedOperationException();

}

} // end inner class Iter

}