queueImpl.java

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package queue;

import java.util.Arrays;

/**
 *
 * @author User
 * @param <T>
 */
public class Queue<T> implements QueueInterface {
    
    private T[] queueLine;
    private final int maxSize = 10;
    
    //queue pointers
    private int queueStart = 0;
    private int queueEnd = 0;
    
    //queue management
    private int totalEnqueued = 0;
    private int totalDeququed = 0;
    
    

    public Queue() {
        this.queueLine = (T[]) new Object[maxSize];
    }
    
        
//    /**
//     * @param args the command line arguments
//     */
//    public static void main(String[] args) {
//        // TODO code application logic here
//    }
    
    
    @Override
    public void enqueue(Object o) {
        if(!isFull()){
            if(queueEnd <= queueLine.length){
                //add element to the position of the questartValue
                //add the queueStart value by 1
                this.queueLine[queueEnd] = (T) o;  
                this.queueEnd++;
            } else if(queueEnd > queueLine.length) {
                this.queueStart = 0;
                this.queueLine[queueEnd] = (T) o;
                this.queueEnd++;
            }       
        } else { //the queue is full 
            expand();
            enqueue(o);
        }
        this.totalEnqueued++;        
    }

    @Override
    public void dequeue() {
        //remove the first element in the queue
        queueLine[this.queueStart] = null;
        if (queueStart <= queueLine.length){
            this.queueStart++;
        } else {
            this.queueStart = 0;
        }
    }

    @Override
    public void clear() {
        Arrays.fill(queueLine, null);
    }

    @Override
    public boolean contains(Object o) {
        for(int i = 0; i<=queueLine.length; i++){
            if(queueLine[i] == o){
                return true;
            }
        }
        return false;
    }

    @Override
    public Object Peek() {
        return queueLine[this.queueStart];
    }

    @Override
    public boolean empty() {
        return false;
    }

    @Override
    public boolean isFull() {
        return queueStart == queueEnd;
    }

    private void expand() {
        //create a new array with double the size
        T[] tempQueue = (T[]) new Object[maxSize * 2];
        //copy the old array to the new array 
        System.arraycopy( queueLine, this.queueEnd, tempQueue, this.queueEnd, (queueLine.length-queueEnd) );
    }

}