Queue Dynamic Array

Queue Dynamic Array

1.  QueueDynamicArrayImpl.java

 package com.nrs.ds.basic;  
 import java.util.Arrays;  
 public class QueueDynamicArrayImpl<T> {  
      Object[] ArrayQueue;  
      int Rear;  
      int Front;  
      int size;  
      public QueueDynamicArrayImpl(int size){  
           this.size = size;  
           ArrayQueue = new Object[this.size];  
           Front = -1;  
           Rear = -1;  
      }  
      /*never full */  
   public Boolean isEmpty(){  
        return (Rear == -1 || Front > Rear);  
   }  
   public void queue(Object newItem){  
        ensureCapacity(Rear +2 );  
        Rear = Rear +1;  
        ArrayQueue[Rear] = newItem;  
        if(Front == -1){  
             Front = 0;  
        }  
   }  
   public T deQueue(){  
        if(isEmpty()){  
             System.out.println("D Queue is Empty");  
             return null;  
        }  
        T ObejctOut = (T) ArrayQueue[Front];  
        Front = Front + 1;  
        return ObejctOut;  
   }  
   public int getSize(){  
        return ArrayQueue.length;  
   }  
   public void ensureCapacity(int minCapacity){  
           int oldCapacity = getSize();  
           if(minCapacity > oldCapacity){  
                int newCapacity = oldCapacity * 2;  
                if(newCapacity < minCapacity){  
                     newCapacity = minCapacity;  
                }  
                ArrayQueue = Arrays.copyOf(ArrayQueue, newCapacity);  
           }  
      }  
 }
2.Test 

 package com.nrs.ds.basic;  
 public class QueueDynamicArrayTest {  
      public static void main(String[] args) {  
           QueueDynamicArrayImpl<Integer> qa = new QueueDynamicArrayImpl<Integer>(2);  
           qa.queue(11);  
           qa.queue(12);  
           System.out.println("Size :"+qa.getSize());  
           qa.queue(3);  
           System.out.println("Size :"+qa.getSize());  
           System.out.println("Dequeu :"+qa.deQueue());  
           System.out.println("Size :"+qa.getSize());  
      }  
 }
Output:

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