链队列的结构示意图：
先进先出。
QueueInterface.java//操作方法接口
package 队列的实现;
public interface QueueInterface {
public void enQueue(Object t);
public Object delQueue();
public int size();
public boolean isEmpty();
public Object head();
public void clear();
}
Node.java//节点类
package 队列的实现;
public class Node<T> {
T data;
Node next;
}
Queue.java//队列的定义和接口实现
package 队列的实现;
public class Queue<T> implements QueueInterface{
Node<T> front,rear;//对头指针，队尾指针
//构造一个空的链队列
public Queue(){
front = new Node<T>();
rear = new Node<T>();
rear = front;
}
//实现接口里的操作
public boolean isEmpty(){
if(front == rear)
return true;
else
return false;
}
public int size(){
int i = 0;
Node<T> p = front.next;
while(p != null){
p = p.next;
i++;
}
return i;
}
public Object head(){
if(this.isEmpty() == false)
return front.next.data;
System.out.println("队列为空，不存在队头元素！");
return 0;
}
public void enQueue(Object obj){
Node<T> p = new Node<T>();
p.data = (T)obj;
rear.next = p;
p.next = null;
rear = p;
}
public Object delQueue(){
T t;
Node<T> p = new Node<T>();
if(this.isEmpty() == true){
System.out.println("队列为空，不能进行删除操作！");
return 0;
}
else{
p = front.next;
front.next = p.next;
if(p.next == null)//出队后队列为空
rear = front;
t = p.data;
p = null;
return t;
}
}
public void clear(){
front = rear;
}
}
TestQueue.java//测试类
package 队列的实现;
public class TestQueue {
public static void main(String[] args) {
Queue<Integer> queue = new Queue<Integer>();
for(int i=1; i<=10; i++){
queue.enQueue(i);
}
System.out.println(queue.size());
System.out.println(queue.isEmpty());
for(int i=1; i<=10; i++){
System.out.print(queue.delQueue() + " ");
}
System.out.println();
System.out.println(queue.isEmpty());
for(int i=1; i<=10; i++){
queue.enQueue(i);
}
System.out.println(queue.isEmpty());
queue.clear();
System.out.println(queue.isEmpty());
}
}
实现结果：
10
false
1 2 3 4 5 6 7 8 9 10
true
false
true