Could one calculate the hashes for each entry, sort them, and then
generate the hash for the collection?
On Thu, 7 Mar 2024 at 06:59, Mark Struberg <strub...@yahoo.de.invalid> 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.
>
> 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.
>
> 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
> >>>>
> >>>>
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> >>>>
> >>>>
> >>
> >>
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