清洁番石榴方式来处理可能为空的集合 [英] Clean Guava way to handle possibly-null collection
问题描述
我有一个方法,它接受一个参数 Collection< Foo> foos
,可能为NULL。我想以 ImmutableSet
结尾输入本地副本。现在我的代码如下所示:
I have a method which takes an argument Collection<Foo> foos
, which could be NULL. I want to end up with a local copy of the input as an ImmutableSet
. Right now my code looks like this:
if (foos == null)
{
this.foos = ImmutableSet.of();
}
else
{
this.foos = ImmutableSet.copyOf(foos);
}
有更简洁的方法吗?如果 foos
是一个简单的参数,我可以做一些像 Objects.firstNonNull(foos,Optional.of())
但是我不确定是否有类似处理集合的东西。
Is there a cleaner way to do this? If foos
was a simple parameter I could do something like Objects.firstNonNull(foos, Optional.of())
but I'm not sure if there is something similar to handle collections.
推荐答案
我不明白为什么你不能使用 Objects.firstNonNull
:
I don't see why you couldn't use Objects.firstNonNull
:
this.foos = ImmutableSet.copyOf(Objects.firstNonNull(foos, ImmutableSet.of()));
你可以用静态导入保存一些输入,如果这是你的事情:
You can save some typing with static imports, if that's your thing:
import static com.google.common.collect.ImmutableSet.copyOf;
import static com.google.common.collect.ImmutableSet.of;
// snip...
this.foos = copyOf(Objects.firstNonNull(foos, of()));
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