Iterator itr = dkItems1.iterator();
while (itr.hasNext()){
DKWorkQueue dk = (DKWorkQueue) itr.next();
if (!dkItems2.contains(dk)){
sb.append(dk.toString() + lineSeparator);
// out.write(dk.toString());out.newLine();
count++;
}
}
any way to do this better?
Let me first rephrase your code into this
equivalent Java5 form (The compiler will actually
generate identical code):
for(DKWorkQueue dk: dkItems1) {if (!dkItems2.contains(dk)) {
sb.append(dk.toString() + lineSeparator);
count++;
}
}
Now, first problem is the "+" operator.
It will construct a separate StringBuilder on the side,
use it, then discard it.
So you should first rewrite it as this:
for(DKWorkQueue dk: dkItems1) {if (!dkItems2.contains(dk)) {
sb.append(dk.toString());
sb.append(lineSeparator);
count++;
}
}
Now, you cannot improve it further unless
you do something special about dkItems1 and dkItems2.
If they are just arbitrary collections, then no, you
have to do item-by-item comparison.
But otherwise, you can use a clever combination
of HashSet/HashMap to speed up the lookup,
as well as possibly avoid the duplication in the first place.
KathyMcDonnella at 2007-7-10 14:28:58 >