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https://issues.apache.org/jira/browse/SANDBOX-404?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13221645#comment-13221645
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Claudio Squarcella edited comment on SANDBOX-404 at 3/3/12 5:13 PM:
--------------------------------------------------------------------
Hi Simo,
good that you moved discussion here so that we can focus.
I don't know if I got your question correctly, but I have answers for both
interpretations :)
* _what if our class has to implement two different kinds of Monoid (e.g.
Addition and Multiplication)?_ I propose to convert our current {{Monoid}} to
{{Addition}} to represent the sum operation (which indeed is how we use it
right know). Then we can add {{Multiplication}} as a completely separate
interface, without the need to be backed by the same "abstract monoid"
(although, of course, theory tells us that they are both monoids):
{code}
public class DoubleOperations
implements Addition, Comparator, Multiplication
{
...
}
{code}
* _what if our class has to be not just a Monoid, but also something else?_
Then we simply add a new interface. I am already thinking of clearly separating
{{Monoid}}/{{Addition}} from {{Comparator}} (see code snippet above).
Algorithms can still enumerate all properties/operations they need, for example:
{code}
public <WO extends Addition<W> & Comparator<W>> HeuristicBuilder<V, WE, W, G,
WO> applyingAStar( WO weightOperations )
{
...
}
{code}
Ciao
Claudio
was (Author: claudio.squarcella):
Hi Simo,
good that you moved discussion here so we can focus.
I don't know if I got your question correctly, but I have answers for both
interpretations :)
* _what if our class has to implement two different kinds of Monoid (e.g.
Addition and Multiplication)?_ I propose to convert our current {{Monoid}} to
{{Addition}} to represent the sum operation (which indeed is how we use it
right know). Then we can add {{Multiplication}} as a completely separate
interface, without the need to be backed by the same "abstract monoid"
(although, of course, theory tells us that they are both monoids):
* _what if our class has to be not just a Monoid, but also something else?_
Then we simply add a new interface. I am already thinking of clearly separating
{{Monoid}}/{{Addition}} from {{Comparator}}
> Simplify weight model
> ---------------------
>
> Key: SANDBOX-404
> URL: https://issues.apache.org/jira/browse/SANDBOX-404
> Project: Commons Sandbox
> Issue Type: Improvement
> Components: Graph
> Reporter: Simone Tripodi
> Attachments: SANDBOX-404.patch
>
>
> As discussed on {{dev@}}, {{Zero}}, {{Semigroup}} and {{Monoid}} can be
> merged directly in one single interface
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