我制作了一个使用 JGraphT 的界面。我的预期用途是Comparable，因为实现Comparable允许对象与某些数据结构一起使用。同样，我有一个 JGraphT 函数，我想使用它来处理任何Distanceable.
public interface Distanceable<E> {
/**
* A representation of the distance between these two objects.
* If the distance between a0 and a1 is undefined, <code>a0.hasEdge(a1)</code> should return false;
* @param o
* @return
*/
public int distance(E o);
/**
* Are these two objects connected?
* @param o
* @return True if the two objects are connected in some way, false if their distance is undefined
*/
public boolean hasEdge(E o);
}
这是我在 JGraphtUtilities 中的 JGraphT 函数。它不是为 定义的Animal，而是为Distanceable：
public static <E extends Distanceable> WeightedGraph<E, DefaultWeightedEdge> graphOfDistances(Set<E> nodes) {
WeightedGraph<E, DefaultWeightedEdge> g = new SimpleWeightedGraph<E, DefaultWeightedEdge>(DefaultWeightedEdge.class);
for (E a : nodes) {
g.addVertex(a);
}
for (E a : nodes) {
for (E a1 : nodes) {
if (a.hasEdge(a1)) {
g.addEdge(a, a1);
g.setEdgeWeight(g.getEdge(a, a1), a.distance(a1));
}
}
}
return g;
}
但它不起作用。编译器在调用此方法的另一个类中的这一行上产生错误：
WeightedGraph<Animal, DefaultWeightedEdge> graphOfAnimals = JGraphtUtilities.graphOfAnimals(zoo);
错误是：
The method graphOfAnimals(Set<Animal>) is undefined for the type JGraphtUtilities
然而，
public class Animal implements Distanceable<Animal> {
我在这里做错了什么？
另一个问题：编译器给出了这个警告：
Distanceable is a raw type. References to generic type Distanceable<E> should be parameterized.
Distanceable如果我想让这个函数适用于所有对象，我想给它什么类型？