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From: Pavel Tupitsyn <ptupitsyn@apache.org>
Date: Fri, 27 Jan 2017 15:38:54 +0300
Message-ID: <CAK2_iMM+gLiUCmXqvgeLL0=iyhVZnM4PY9W7JRZh+v8VY=jVfg@mail.gmail.com>
Subject: Re: Binary object hash code resolution in Apache Ignite 2.0
To: dev@ignite.apache.org
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archived-at: Fri, 27 Jan 2017 12:39:27 -0000

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Makes sense to me.

Ticket for reference: https://issues.apache.org/jira/browse/IGNITE-4558

On Fri, Jan 27, 2017 at 1:37 PM, Vladimir Ozerov <vozerov@gridgain.com>
wrote:

> Folks,
>
> Historically we have fundamental flaw in how we deal with hashCode/equals
> for BinaryObjects:
> 1) hashCode() is taken from original deserialized object.
> 2) But equals() is performed through binary array comparison.
>
> We recently introduced BinaryIdentityResolver [1] as a part of DML feature,
> but we didn't change any existing semantics, because it might broke
> applications running AI 1.x.
>
> Now I am thinking on how it should be designed properly in AI 2.0, and here
> is my idea:
> 1) Every type will use BinaryArrayIdentityResolver [2] unless it is
> overridden in config
> 2) Hash code is calculated only using resolver
> 3) Equality is determined only using resolver
> 4) Never ever use Object.hashCode().
>
> This way we will have clean and consistent hashCode/equals semantics.
>
> Any objections or comments?
>
> Vladimir.
>
> [1]
> https://github.com/apache/ignite/blob/master/modules/
> core/src/main/java/org/apache/ignite/binary/BinaryIdentityResolver.java
> [2]
> https://github.com/apache/ignite/blob/master/modules/
> core/src/main/java/org/apache/ignite/binary/BinaryArrayIdentityResolver.
> java
>

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