[ovirt-devel] Implementing equals & hashCode methods

[Yair Zaslavsky]

----- Original Message -----
> From: "Yevgeny Zaspitsky" <yzaspits at redhat.com>
> To: devel at ovirt.org
> Sent: Sunday, May 25, 2014 3:33:31 PM
> Subject: [ovirt-devel] Implementing equals & hashCode methods
> 
> Hi All,
> 
> Recently I reviewed a patch that adds a new business entity to the engine.
> The entity class has the following members:
> 
>     * id
>     * data center id
>     * name
>     * type
>     * some other properties that do not belong to the entity key
> 
> The equals & hashCode methods were implemented in a way that include all
> members.
> I asked the patch author to change that, so it'll include only business key
> (data center id, name and type), which define the entity uniqueness.
> Also I found that many other business entities are implemented in a similar
> way (include all class members in equals & hashCode).
> 
> I'm a new to oVirt, so I'd like to ask your opinion on the issue.
> 
> 
>     1. Do you agree with my approach on equals & hashCode.
>     2. If you agree with my approach in general, should we implement it in
>     the new introduced code or should we adhere to the old convention even
>     we do not agree with it?
>     3. Should we re-factor the old code (it might be dangerous as we do have
>     enough unit test coverage)?
> 
> Thanks in advance,
> Yevgeny

I assume your idea came (at least from ) the way identify is defined at Hibernate.
The advantages are obvious - 
a. shorter code
b. let's time to compute

However, I fear this is may lead to some bugs if identities are not defined well.

Regarding 3 - might be dangerous as we don't have enough unit test coverage, probably.
Actually, IMHO the situation with DAO tests which uses equals is quite good.
For hashCode - I assume you have a point



> 
> _______________________________________________
> Devel mailing list
> Devel at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/devel