链队列
实际上就是单链表，只是规定了删除在队头进行，添加在队尾进行。
链队列代码结构
package list.queue;
public interface Queuable<T>;
public class QueueNode<T>;
public class LinkedQueue<T>;
package list;
public class TestLinkedQueue;
链队列公共接口
package list.queue;
public interface Queuable<T> {
public int length();
public boolean destroyQueue();
public void clear();
public boolean isEmpty();
public T getHead();
public boolean add(T element);
public T remove();
}
链队列节点类
package list.queue;
public class QueueNode<T> {
private T data;
private QueueNode next;
QueueNode() {
this(null);
}
QueueNode(T data) {
this(data,null);
}
QueueNode(T data, QueueNode<T> next) {
this.data = data;
this.next = next;
}
public QueueNode<T> getNext() {
return this.next;
}
public T getData() {
return this.data;
}
public void setNext(QueueNode<T> next) {
this.next = next;
}
public void setData(T data) {
this.data = data;
}
public String toString() {
return getData().toString();
}
}
链队列实现类
//**************************************************************************
//*队列之链式存储结构链队列-JAVA实现
//*@author Nora-Xie
//*@time 2013-10-07PM22:00
//************************************************************************** package list.queue; import list.queue.QueueNode;
import list.queue.Queuable; //链队列实际就是单链表，只不过是限定了其删除在队头，插入在队尾而已
public class LinkedQueue<T> implements Queuable<T> {
private QueueNode<T> front,rear; public LinkedQueue() {
this(null);
} public LinkedQueue(T element) {
if(element == null) {
front = new QueueNode<T>(null);
rear = front;
}else {
rear = new QueueNode<T>(element);
front = new QueueNode<T>(null,rear);
}
} public int length(){
if(isEmpty()) return 0;
int k = 1;
QueueNode<T> temp = front.getNext();
while(temp != rear) {
k++;
temp = temp.getNext();
}
return k;
} public boolean destroyQueue() {
return false;
} public void clear() {
if(isEmpty()) return;
while(front.getNext() != rear) {
remove();
}
remove();
} public boolean isEmpty() {
return front == rear;
} public T getHead() {
if(isEmpty()) return null;
return front.getNext().getData();
} public boolean add(T element) {
if(element == null) return false;
QueueNode<T> temp = front;
rear.setNext(new QueueNode<T>(element));
rear = rear.getNext();
return true;
} public T remove() {
if(isEmpty()) return null;
T element = front.getNext().getData();
if(length() == 1)
rear = front;
else{
front.setNext(front.getNext().getNext());
}
return element;
} public String toString() {
if(isEmpty()) return "[ ]";
StringBuffer sb = new StringBuffer("[ ");
QueueNode<T> temp = front.getNext();
while(temp != rear) {
sb.append(temp+" ");
temp = temp.getNext();
}
sb.append(temp+" ");
sb.append("]");
return sb.toString();
} }
链队列测试类
package list; import list.queue.LinkedQueue;
import list.queue.Queuable;
import list.queue.QueueNode; public class TestLinkedQueue {
public static void main(String[] args) {
Queuable<String> queue = new LinkedQueue<String>("A");
System.out.println("queue="+queue+" queue.length="+queue.length());
queue.add("B");
System.out.println("queue="+queue+" queue.length="+queue.length());
System.out.println("the removint element="+queue.remove());
System.out.println("queue="+queue+" queue.length="+queue.length());
queue.add("C");
queue.add("D");
System.out.println("queue="+queue+" queue.length="+queue.length());
queue.clear();
System.out.println("queue="+queue+" queue.length="+queue.length());
System.out.println("queue is empty? "+queue.isEmpty());
queue = new LinkedQueue<String>("a");
System.out.println("queue="+queue+" queue.length="+queue.length());
queue.add("b");
queue.add("c");
queue.add("d");
queue.add("e");
queue.add("f");
queue.add("g");
System.out.println("queue="+queue+" queue.length="+queue.length());
System.out.println("queue's head is ["+queue.getHead()+"]");
queue.remove();
System.out.println("queue="+queue+" queue.length="+queue.length());
System.out.println("queue's head is ["+queue.getHead()+"]");
}
}