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From "Vincenzo Vitale (JIRA)" <j...@apache.org>
Subject [jira] Commented: (BEANUTILS-320) Implement equals, hashCode and toString replacement
Date Wed, 09 Jul 2008 10:25:32 GMT

    [ https://issues.apache.org/jira/browse/BEANUTILS-320?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12611973#action_12611973
] 

Vincenzo Vitale commented on BEANUTILS-320:
-------------------------------------------

Hi Niall,

thanks for the comment.

I think you are right, commons lang will be more appropriate... I will new improvement file
there.

BTW, I also created yesterday a project in GoogleCode for this http://code.google.com/p/simplestuff/
, just to beginning the "coming out" :-)


Thanks,
V.

> Implement equals, hashCode and toString replacement
> ---------------------------------------------------
>
>                 Key: BEANUTILS-320
>                 URL: https://issues.apache.org/jira/browse/BEANUTILS-320
>             Project: Commons BeanUtils
>          Issue Type: New Feature
>          Components: Bean / Property Utils
>            Reporter: Vincenzo Vitale
>            Priority: Minor
>
> In my company (TomTom), we have internally developed a replacement of the equals, hashcode
and toString methods.
> The base idea is to use the annotation @BusinessObject at the class level and @BusinessField
at field level. Then what developers normally do is to override the three methods delegating
to the tomtom.BeanUtils methods:
>       @Override
>         public boolean equals(Object obj) {
>             return BeanUtils.equals(this, obj);
>         }
>         @Override
>         public int hashCode() {
>             return BeanUtils.hashCode(this);
>         }
>         @Override
>         public String toString() {
>             return BeanUtils.toString(this);
>         }
> And i.e. the method signature of equals is:
>     /**
>      * Compare two @BusinessObject beans comparing only the {@link BusinessField}
>      * annotated fields.
>      * 
>      * @param firstBean First bean to compare.
>      * @param secondBean Second bean to compare.
>      * @return The equals result.
>      * @throws IllegalArgumentException If one of the beans compared is not an
>      *         instance of a {@link BusinessObject} annotated class.
>      */
>     public static boolean equals(Object firstBean, Object secondBean);
> In the last versions of EqualsBuilder now there is the new method reflectionEquals...
but there is no a way to specify what to include in the comparison. With our two annotations
we are able to let developers exactly define what need to be included in a Business comparison,
as i.e. normally required by persistence framework like hibernate. 
> The current implementation can also handle more complex case, comparing correctly totally
different kind of objects.
> For example if all my business logic cares only about the color, I can define:
> @BusinessObject
> public class Cat{
> }
> public class ColouredCat extends Cat{
> @BusinessField
> private String color;
> getter/setter
> }
> @BusinessObject
> public class SunSet{
> @BusinessField
> private String color="red";
> getter/setter
> }
> and then compare any instance of ColouredCat with a Sunset instance, finding out that
the redColouredCat is (for my business logic) equal to a default instance of a Sunset. And
also more tricky cases are handled (different BusinessFields, no BusinessObject annotation
and so on).
> We intensively use Hibernate and the utility demonstrated to work fine with CGLIB proxies

> We always thought about the possibility to create a new Open Source project but then
it was decided it would be better adding the feature to an already well know open source project...
> If you are interested I can send you more details. How can we (me more one other developer)
eventually became committers?
> Thanks in advance,
> Vicio.
> P.s.: an utility method to automatically populate the BusinessFields of a BusinessObject
is also implemented.

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