Spark Shen 写道:
> Hi :
> Following is the discussion about JIRA 1492, shall we discuss it here?
>
> public class SubMapTest extends TestCase {
> public void testSubclass() {
> HashMap map = new HashMap();
> map.put("a", "a");
> SubMap map2 = new SubMap(map); // Harmony will throw an unexpected
> exception here.
> }
> }
>
> class SubMap<K, V> extends HashMap<K, V> {
>
> public V put(K key, V value) {
> throw new RuntimeException();
> }
> }
>
>
> >Nathan Beyer
> >Harmony's behavior may be different in this case, but I'm not sure I
> would consider this a valid issue. What's a real use case for this
> type of sub-classing?
> [ Show » <http://issues.apache.org/jira/browse/HARMONY-1492> ]
> Nathan Beyer
> <http://issues.apache.org/jira/secure/ViewProfile.jspa?name=nbeyer>
> [18/Sep/06 08:41 PM] Harmony's behavior may be different in this case,
> but I'm not sure I would consider this a valid issue. What's a real
> use case for this type of sub-classing?
>
>
<http://issues.apache.org/jira/secure/ViewProfile.jspa?name=spark+shen>>Spark
> Shen
> >What if change the RuntimeException to UnsupportedOperationException?
> [ Show » <http://issues.apache.org/jira/browse/HARMONY-1492> ]
> spark shen
>
<http://issues.apache.org/jira/secure/ViewProfile.jspa?name=spark+shen>
> [18/Sep/06 08:48 PM] What if change the RuntimeException to
> UnsupportedOperationException?
>
> >Alexey Petrenko
> >I'm not sure that this is a valid issue to.
> >As far as I understood the issue is that Harmony calls put method in
> constructor while RI does not. Right?
>
> >If so I do not see any issue here.
>
I can not figure out what RI does. And please refer to JIRA 839, it
reports similar use case.
My point here is
1. we may not be able to predict how users will use our library.
2. Users could guess our implementation w/o difficulty, which
contradicts the encapulation priciple.
So I prefer to follow RI on this behavior.
When changing to UnsupportedOperationException, the use case is more
practical, since it is highly like that put operation is not supported.
But it seems not so practical that this sub-hashMap can not be
instantiated. May be one more assertion can convince you that this is
bug.
public class SubMapTest extends TestCase {
public void testSubclass() {
HashMap map = new HashMap();
map.put("a", "a");
SubMap map2 = new SubMap(map);
assertEquals(1, map2.size());
}
}
class SubMap<K, V> extends HashMap<K, V> {
public SubMap(Map<? extends K, ? extends V> m) {
super(m);
}
public V put(K key, V value) {
throw new RuntimeException();
}
}
Best regards
--
Spark Shen
China Software Development Lab, IBM
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