One comment about the collection comparison...
For any collection that actually implements List, equality should *include*
order, not attempt to ignore it, right? The contract of a list is that the
order is consistent, and two lists with the same items in different order,
should not be considered equal.
e.g for List:
Best case scenario - The lengths are different and you dont have to check
any equalities
Worst case scenario - every item is equal and you have to iterate both
lists completely
Remaining Cases - Item [i] is different and you dont have to check
anything past that
(For pretty much any collection I think the best case is the same)
For sets, maybe it could be optimized by creating a new collection and
removing items as you find them, so each step necessarily gets smaller? Not
sure about this though.
On Thu, Mar 7, 2024 at 8:55 AM Gary D. Gregory <ggreg...@apache.org> wrote:
> On 2024/03/07 06:58:30 Mark Struberg wrote:
> > The question to me is how we can make it more robust.
> > In a Collection (but actually also in most lists) the order in which you
> get the values (Iterator or get(i)) is not deterministic. It can be
> different in one list than in another - even if they contain the exact same
> items.
>
> Hm, so to iterate through Lists in parallel would work but not with Sets.
>
> >
> > Not yet sure how to work around this. We can probably try to sort it
> first, but then again, if they do not implement Comparable it won't help
> much. Or do a containsElement based on reflection as well - but that would
> be rather slow.
>
> This is one of those: If you want support for the feature, it'll work, but
> it'll be slow because there is no other way to do it (for now if ever).
>
> Gary
>
> >
> > Same with Maps. There is a good reason why the key at least should
> implement equals/hashCode. If this is not the case, then we are not able to
> implement this properly I fear.
> >
> > Any ideas?
> >
> > LieGrue,
> > strub
> >
> > > Am 06.03.2024 um 15:53 schrieb Gary Gregory <garydgreg...@gmail.com>:
> > >
> > > Ah, right, custom "non-equalable" _inside_ Collections and Maps...
> > >
> > > For the diff, I'd suggest you test and iterable over a Collection
> > > instead of a List.
> > >
> > > Then you'd need a separate test and traversal for Map instances.
> > >
> > > (Still no common super-interface in Java 21 for Collections and
> Maps...)
> > >
> > > Gary
> > >
> > > On Wed, Mar 6, 2024 at 7:40 AM Mark Struberg <strub...@yahoo.de.invalid>
> wrote:
> > >>
> > >> Hi Gregory!
> > >>
> > >> I did try this out and figured that I didn't think it though. Maybe I
> need to go a few steps back and explain the problem:
> > >>
> > >> I have the following constellation
> > >>
> > >> public class SomeInnerDTO {int field..} // NOT implements equals!
> > >> public class TheOuterDTO{ List<SomeInnerDTO> innerList;..}
> > >>
> > >> My problem is that reflectionEquals (which I use in a unit test)
> tries to introspect fields even in java.util.classes. And for getting the
> values of those classes it tries to call a setAccessible(true);
> > >> And obviously here it fails. There is a ticket already open [1] which
> sugggests to use trySetAccessible. But I fear that will still do nothing
> and you won't get access to those inner knowledge inside
> java.util.LinkedList etc.
> > >>
> > >> And using equals() on the List sadly won't help either, as the
> SomeInnerDTO would also get compared with equals(), but that will obviously
> use identity comparison only :(
> > >>
> > >>
> > >> What I did for now (running all tests with a few projects right now,
> but looks promising):
> > >>
> > >> diff --git
> a/src/main/java/org/apache/commons/lang3/builder/EqualsBuilder.java
> b/src/main/java/org/apache/commons/lang3/builder/EqualsBuilder.java
> > >> index ff5276b04..cf878da40 100644
> > >> ---
> a/src/main/java/org/apache/commons/lang3/builder/EqualsBuilder.java
> > >> +++
> b/src/main/java/org/apache/commons/lang3/builder/EqualsBuilder.java
> > >> @@ -978,6 +978,16 @@ public EqualsBuilder reflectionAppend(final
> Object lhs, final Object rhs) {
> > >> if (bypassReflectionClasses != null
> > >> && (bypassReflectionClasses.contains(lhsClass) ||
> bypassReflectionClasses.contains(rhsClass))) {
> > >> isEquals = lhs.equals(rhs);
> > >> + } else if (testClass.isAssignableFrom(List.class)) {
> > >> + List lList = (List) lhs;
> > >> + List rList = (List) rhs;
> > >> + if (lList.size() != rList.size()) {
> > >> + isEquals = false;
> > >> + return this;
> > >> + }
> > >> + for (int i = 0; i < lList.size(); i++) {
> > >> + reflectionAppend(lList.get(i), rList.get(i));
> > >> + }
> > >> } else {
> > >>
> > >> I'm rather sure this is still not enough and there are plenty other
> cases to consider. Like e.g. handling Maps etc.
> > >> But at least that's the direction I try to approach it right now. And
> of course this new part should potentially also be enabled by a flag...
> > >>
> > >> Will keep you updated.
> > >>
> > >> txs and LieGrue,
> > >> strub
> > >>
> > >>
> > >> [1] https://issues.apache.org/jira/browse/LANG-1711
> > >>
> > >>> Am 06.03.2024 um 13:18 schrieb Gary Gregory <garydgreg...@gmail.com
> >:
> > >>>
> > >>> This sounds like a good idea to try. I would call the option
> something else
> > >>> though. We would not skip calling equals if it is defined right? How
> about
> > >>> "useEqualsIfPresent".
> > >>>
> > >>> Gary
> > >>>
> > >>> On Wed, Mar 6, 2024, 5:03 AM Mark Struberg <strub...@yahoo.de.invalid
> >
> > >>> wrote:
> > >>>
> > >>>> Hi!
> > >>>>
> > >>>> I have a question about EqualsBuilder#reflectionEquals. From Java9
> onwards
> > >>>> we get more and more nasty module problems. Mainly because the code
> tries
> > >>>> to recurse into java.util.* classes as well.
> > >>>> I know that I can use setBypassReflectionClasses for those. But
> wouldn't
> > >>>> it be fine to have an additional switch to 'skipOnCustomEquals' or
> similar?
> > >>>>
> > >>>> The idea is to only use reflection on classes which do not provide
> their
> > >>>> own equals method. One can test this imo rather easily by checking
> whether
> > >>>> classInQuestion.getMethod("equals",
> Object.class).getDeclaringClass() !=
> > >>>> Object.class
> > >>>> Do that for lhs and rhs and if both fit the criteria -> invoke
> equals
> > >>>>
> > >>>> Wdyt of that idea? Worth trying or is there already a better
> solution?
> > >>>> With the new flag we can make sure that we do not change the current
> > >>>> behaviour for existing use cases.
> > >>>>
> > >>>> LieGrue,
> > >>>> strub
> > >>>>
> > >>>>
> > >>>>
> ---------------------------------------------------------------------
> > >>>> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
> > >>>> For additional commands, e-mail: dev-h...@commons.apache.org
> > >>>>
> > >>>>
> > >>
> > >>
> > >> ---------------------------------------------------------------------
> > >> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
> > >> For additional commands, e-mail: dev-h...@commons.apache.org
> > >>
> > >
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
> > > For additional commands, e-mail: dev-h...@commons.apache.org
> > >
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
> > For additional commands, e-mail: dev-h...@commons.apache.org
> >
> >
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org
> For additional commands, e-mail: dev-h...@commons.apache.org
>
>
