How to test
InventorySet.iterator(), where we don't know the order...
+ Create a local HashSet<Video> and an InventorySet.
+ Put some videos in the InventorySet.
+ Put corresponding Videos in the HashSet. Use Video, not Record,
since you cannot create records directly. You could also use
strings such as "Title1 (2000) : Director1 [10,0,0]"
+ Now call InventorySet.iterator() and go through the elements.
For each record returned do the following:
++ Make sure an equivalent video is in the local HashSet
++ Remove the equivalent video from the HashSet
+ Once you're done with the iterator, make sure the local HashSet is
empty.
To test InventorySet.iterator(), where we do know the order ...
+ Create class that implements Comparator. When called, the
arguments will be Records. For example, the following class will
compare Records based on the number owned:
Class NumOwnedComparator implements java.util.Comparator {
public int compare (Object o1, Object o2) {
Record r1 = (Record)o1;
Record r2 = (Record)o2;
return r2.numOwned() - r1.numOwned();
}
}
or use the following in Java 1.5 to get rid of "unchecked
conversion" warnings:
class NumOwnedComparator implements java.util.Comparator<Record> {
public int compare (Record r1, Record r2) {
return r2.numOwned() - r1.numOwned();
}
}
+ Continue as before, but this time use a List to keep the videos in
expected order.
If you want some more reading about Comparators/Comparable see:
Making Java Objects Comparable
by Budi Kurniawan
http://www.onjava.com/pub/a/onjava/2003/03/12/java_comp.html
