java数据结构与算法之双向循环队列的数组实现方法

package source;
public class Deque {
 private int maxSize;
 private int left;
 private int right;
 private int nItems;
 private long[] myDeque;
 //constructor
 public Deque(int maxSize){
 this.maxSize = maxSize;
 this.myDeque = new long[this.maxSize];
 this.nItems = 0;
 this.left = this.maxSize;
 this.right = -1;
 }
 //insert a number into left side
 public void insertLeft(long n){
 if(this.left==0) this.left = this.maxSize;
 this.myDeque[--this.left] = n;
 this.nItems++;
 }
 //insert a number into right side
 public void insertRight(long n){
 if(this.right==this.maxSize-1) this.right = -1;
 this.myDeque[++this.right] = n;
 this.nItems++;
 }
 //remove from left
 public long removeLeft(){
 long temp = this.myDeque[this.left++];
 if(this.left==this.maxSize) this.left = 0;
 this.nItems--;
 return temp;
 }
 //remove from right
 public long removeRight(){
 long temp = this.myDeque[this.right--];
 if(this.left==-1) this.left = this.maxSize-1;
 this.nItems--;
 return temp;
 }
 //return true if deQue is empty
 public boolean isEmpty(){
 return (this.nItems==0);
 }
 //return size of the deQue
 public int size(){
 return this.nItems;
 }
}