-java: queue

CircularQueue.java

package com.hackerrank.challenges;

import java.util.Arrays;

/**
 * @author Alexander Krasniansky
 */
@SuppressWarnings("unchecked")
public class CircularQueue<T> implements Queue<T> {

    private Object[] queue;

    private int head;
    private int tail;
    private int size;

    public CircularQueue(int size) {
        this.size = size;
        this.queue = new Object[size];
    }

    public void put(T element) {
        queue[tail % size] = element;
        tail = (tail + 1) % size;
    }

    public T take() {
        try {
            if (isEmpty()) throw new RuntimeException("The queue is empty");
            return (T) queue[head];
        } finally {
            queue[head] = null;
            head = (head + 1) % size;
        }
    }

    public boolean isEmpty() {
        return tail - head == 0;
    }

    @Override
    public String toString() {
        return "CircularQueue=" + Arrays.toString(queue);
    }
}

Queue.java

package com.hackerrank.challenges;

/**
 * @author Alexander Krasniansky
 */
public interface Queue<T> {

    void put(T element);

    T take();

    boolean isEmpty();

}