Re: Collection Issue

From:
Eric Sosman <Eric.Sosman@sun.com>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 25 Sep 2008 16:30:41 -0400
Message-ID:
<1222374521.352127@news1nwk>
adrian.bartholomew@gmail.com wrote:

[...]
    public void removeAll(List<T> l, List<T> c) {
        Iterator<T> e = l.iterator();
        while (e.hasNext()) {
            if (contains(l, e.next())) {//when it reaches the element,
it throws a null exception
                e.remove(); // even though it DOES contain
it.
            }
        }
    }
[...]
    public boolean contains(List<T> c, T l) {
        for (T e: c) {
            if (e == l) return true;
        }
        return false;
    }


     What do you mean by "when it reaches the element?" What is
"the" element you're referring to? Unless I've missed something,

     - The loop examines every element of List `l' in turn.

     - It tests whether each element of `l' is contained in `l',
       which seems like nothing more than a slow way to write `true'.

     - Having determined that an element found in `l' is in fact
       contained in `l', it then removes the element via the Iterator.

     - When the loop finishes, `l' should be empty.

     - The List `c' plays no role, and I don't see why it's there at
       all.

     Are you sure this is your actual code?

--
Eric.Sosman@sun.com

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