Re: Let "for" loop treat "null" as empty List ?

From:

Mayeul <mayeul.marguet@free.fr>

Newsgroups:

comp.lang.java.help

Date:

Tue, 25 Jan 2011 11:35:39 +0100

Message-ID:

<4d3ea6a4$0$13574$426a34cc@news.free.fr>

On 25/01/2011 11:07, Robin Wenger wrote:

I have the following code:

public void myiteration(List<MyObject> mylist) {

   if (mylist != null) {
      for ( MyObject mo : mylist) {
          ... }
      }

As you can see I have to check at first whether the passed list is null or not.
If the is null and have no "if" check on the null value then the prog would crash at the "for" loop.

Ok, it works as shown before.

However I would appreciate to be able to treat an null value as an empty list.
I want to omit the leading, wrapping "if" check.

Is this possible somehow?

Maybe with a workaround like:

for (MyObject mo : mylist; (mylist = NOT(null)))

Well you /can/ make something like

if(mylist == null) {
mylist = Collections.emptyList();
}

before the loop. Same difference really.

I think you should really make a best effort of not sending null Lists
as parameter of the method in the first place, though. That way, the
method can correctly throw a NullPointerException when that happens, as
it must not happen.

--
Mayeul