[jira] [Comment Edited] (LANG-780) Add HashCodeBuilder.append(Enum value)

["Duncan Jones (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/LANG-780?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13168966#comment-13168966 ] 

Duncan Jones edited comment on LANG-780 at 10/10/14 6:49 AM:
-------------------------------------------------------------

{quote}
Using Enum#name() means that the same hashCode will be used for different Enum instances that happen to have the same name.

That seems like quite a disadvantage to me.
{quote}

Proposed method is just an example and to avoid your concent we can use something like following

{code:java}
private static int hashCodeForEnum(Enum enumItem)
{ return (enumItem.getClass().getName()+enumItem.name()).hashCode(); }
{code}

But again this is just proposal. I think initial point is valid. I want to see the same hashCode for enum using HashCodeBuilder. This would be great.


was (Author: jakop):
"Using Enum#name() means that the same hashCode will be used for different Enum instances that happen to have the same name.

That seems like quite a disadvantage to me."(c)
Proposed method is just an example and to avoid your concent we can use something like following

private static int hashCodeForEnum(Enum enumItem)
{ return (enumItem.getClass().getName()+enumItem.name()).hashCode(); }

But again this is just proposal. I think initial point is valid. I want to see the same hashCode for enum using HashCodeBuilder. This would be great.

> Add HashCodeBuilder.append(Enum value)
> --------------------------------------
>
>                 Key: LANG-780
>                 URL: https://issues.apache.org/jira/browse/LANG-780
>             Project: Commons Lang
>          Issue Type: New Feature
>          Components: lang.builder.*
>    Affects Versions: 2.5
>            Reporter: Alex Pokotilo
>             Fix For: Review Patch
>
>         Attachments: LANG-780.patch
>
>   Original Estimate: 2h
>  Remaining Estimate: 2h
>
> Since Enum's hashCode return different values between calls this can cause different values if enum appended to HashCodeBuilder 
> IMHO adding append for enum would be enough to solve this entirely
> {code:java}
> public org.apache.commons.lang.builder.HashCodeBuilder append(Enum value)
> {
>  append(value.name().hashCode());
>  return this;
> }
> {code}



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