我写了这个谓词,声纳正在抱怨它。我不知道如何修复此违规行为。请帮忙:
import com.google.common.base.Predicate;
import java.util.Map;
public final class FooPredicate {
private FooPredicate(){}
public static Predicate<Map.Entry<Long,Long>> isFirstElement(final Long o) {
return new Predicate<Map.Entry<Long,Long>>() {
@Override
public boolean apply(Map.Entry<Long,Long> foo) {
return foo.getKey().equals(o);
}
};
}
}
它正在抱怨apply方法的Foo参数。
Dodgy - Parameter must be nonnull but is marked as nullable foo must be nonnull but is marked as nullable
apply方法被定义为可以为空,我对此无能为力。声纳和番石榴在这里战斗不是吗?
> boolean apply(@Nullable
> T input)
>
> Returns the result of applying this predicate to input. This method is
> generally expected, but not absolutely required, to have the following
> properties:
>
> Its execution does not cause any observable side effects.
> The computation is consistent with equals; that is, Objects.equal(a, b) implies that predicate.apply(a) ==
> predicate.apply(b)).
>
> Throws:
> NullPointerException - if input is null and this predicate does not accept null arguments
答案 0 :(得分:4)
你在做foo.getKey()
。如果foo
为null将抛出NullPointerException,但您没有声明foo
不能为空。
使用前请先检查foo
。
if (foo != null) {
return foo.getKey().equals(o);
} else {
return null;
}