Java PriorityQueue Comparator – 如何/何时排序?
我正在初始化一个优先级队列,如:
strategy = new FuelPriority(); incoming = new PriorityQueue(1, strategy);
我的Comparator类的代码是:
public class FuelPriority implements Comparator { public int compare(Object o1, Object o2) { Vehicle a1 = (Vehicle) o1; Vehicle a2 = (Vheicle) o2; return Integer.compare(a1.getFuelLevel(), a2.getFuelLevel()); } }
运行模拟后,元素根本没有排序 – 它们是随机的; 我在FuelPriority
类的compare方法中设置了一个断点,但根本没有调用它。 我在这里错过了什么吗?
除了你的代码上的拼写错误,它对我有用。
import java.util.Comparator; import java.util.PriorityQueue; public class StackOverflow { public static void main(String[] args) { FuelPriority strategy = new FuelPriority(); PriorityQueue incoming = new PriorityQueue (4, strategy); incoming.add(new Vehicle("car1", 10)); incoming.add(new Vehicle("car2", 20)); incoming.add(new Vehicle("car3", 15)); incoming.add(new Vehicle("car4", 1)); // to retrieve the elements in order while (!incoming.isEmpty()) { System.out.println(incoming.poll()); } } } class FuelPriority implements Comparator
API表示不保证PriorityQueue迭代器以任何特定顺序遍历优先级队列的元素。 它只能保证轮询,删除,查看和元素访问队列头部的元素(最少元素)