java - 祖先列表作为流

Question

如何在 Java 8 中将此 while 循环转换为流？

    Location toTest = originalLocation;
    while(true){
        toTest = toTest.getParentLocation();
        if (toTest==null) {
            break;
        }
        parents.add(toTest);
    }

假设 Location 沿着 :

@Data
public class Location{
    private String name;
    private Location parentLocation;
}

看起来应该是:

Stream.iterate(location, l -> l.getParentLocation()).collect(Collectors.toList());

但是这给了我一个 NullPointerException。我假设是 getParentLocation() 返回 null...

有人能帮忙吗？

Answer 1

JDK9解决方案:

Stream.iterate(location, Objects::nonNull, Location::getParentLocation)
      .collect(Collectors.toList());