java 优先级队列

优先级队列，队列头部存放的是优先级最高的元素。
package prioritydemo1;

import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.Queue;

public class prioritylist {

private String name;
private int num;

//定义属性（名字和优先级）
public prioritylist(String name, int num) {

this.name = name;
this.num = num;
}
//构造函数
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getNum() {
return num;
}
public void setNum(int num) {
this.num = num;
}

@Override
public String toString() {
return  getName() + "-" + getNum();
}

public static void main(String args[]) {
Comparator<prioritylist> demo1 = new Comparator<prioritylist>() {

public int compare(prioritylist o1, prioritylist o2) {
// TODO Auto-generated method stub
int num1 = o1.getNum();
int num2 = o2.getNum();
if(num1 > num2){
return 1;
}
else if(num1 < num2) {
return -1;
}
else return 0;
}
};
//定义比较容器，compare函数中定义的是优先级顺序，num1>num2时返回正数，所以0的优先级比1大。小的数优先级高。

Queue<prioritylist> demo2 = new PriorityQueue<prioritylist>(11,demo1);
//定义优先级队列（定义容量和比较容器）
 prioritylist t1 = new prioritylist("t1",2);
prioritylist t3 = new prioritylist("t3",3);
prioritylist t2 = new prioritylist("t2",6);
prioritylist t4 = new prioritylist("t4",0);
demo2.add(t1);
demo2.add(t3);
demo2.add(t2);
demo2.add(t4);
System.out.println(demo2.poll().toString());
//输出队列头部元素。

}
}