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Posted to user@giraph.apache.org by Nick West <ni...@benchmarksolutions.com> on 2012/08/01 16:48:10 UTC

package-private methods in Vertex/BasicVertex

Hi,

There are several methods in Vertex/BasicVertex that are declared as abstract but without any access modifier specified.  They are:

    abstract void putMessages(Iterable<M> messages);
    abstract void releaseResources();

This has the effect that they both have the access modifier package-private.  The effect of this is that only classes in the giraph package that extend Vertex can override the method.  Specifically, any Vertex implementation not in the giraph package cannot override these methods.

Is this the intended behavior?  I think an easy fix would to be to explicitly declare them as protected, which would allow classes outside of the package to override these methods.

I've looked into using several of the other predefined vertex types (EdgeListVertex, HashMapVertex, etc), which override these methods. However, in these classes the write and readFields methods are declared final, limiting the amount of customization one can make to these classes.

If you have any alternative suggestions, I'd be happy to hear them.

Thanks,
Nick West

Benchmark Solutions
101 Park Avenue - 7th Floor
New York, NY 10178
Tel +1.212.220.4739 | Mobile +1.646.267.4324
www.benchmarksolutions.com <http://www.benchmarksolutions.com/>
[cid:image001.png@01CCA50E.43B4A860]

Re: package-private methods in Vertex/BasicVertex

Posted by Nick West <ni...@benchmarksolutions.com>.

Thanks for the replay; I had failed to see that post yesterday when searching about this.

Reading the discussion brought up a related question:

If a vertex is to have "state", is it better to store this in an extended vertex value object or as member variables of the class and override the readFields and write methods for the vertex?

(Note that the second option isn't possible at the moment, since the only extendable vertex types have those methods finalized.)  And a related question:

In the life a vertex, is it ever instantiate without either using the readFields (which can restore the member variables) or the vertex reader class provided by the user (where the user can set the member variables)?

If there are other ways in which a vertex is instantiated, it would be good to know about, for the above reason.

Thanks,
Nick

On Aug 1, 2012, at 11:07 AM, Alessandro Presta wrote:

Hi Nick,

Thanks for pointing this out.
Here's a relevant discussion that was just recently started: https://issues.apache.org/jira/browse/GIRAPH-272.
Hopefully we get this sorted out soon.

Alessandro

From: Nick West <ni...@benchmarksolutions.com>>
Reply-To: "user@giraph.apache.org<ma...@giraph.apache.org>" <us...@giraph.apache.org>>
Date: Wednesday, August 1, 2012 3:48 PM
To: "user@giraph.apache.org<ma...@giraph.apache.org>" <us...@giraph.apache.org>>
Subject: package-private methods in Vertex/BasicVertex

Hi,

There are several methods in Vertex/BasicVertex that are declared as abstract but without any access modifier specified.  They are:

    abstract void putMessages(Iterable<M> messages);
    abstract void releaseResources();

This has the effect that they both have the access modifier package-private.  The effect of this is that only classes in the giraph package that extend Vertex can override the method.  Specifically, any Vertex implementation not in the giraph package cannot override these methods.

Is this the intended behavior?  I think an easy fix would to be to explicitly declare them as protected, which would allow classes outside of the package to override these methods.

I've looked into using several of the other predefined vertex types (EdgeListVertex, HashMapVertex, etc), which override these methods. However, in these classes the write and readFields methods are declared final, limiting the amount of customization one can make to these classes.

If you have any alternative suggestions, I'd be happy to hear them.

Thanks,
Nick West

Benchmark Solutions
101 Park Avenue - 7th Floor
New York, NY 10178
Tel +1.212.220.4739 | Mobile +1.646.267.4324
www.benchmarksolutions.com <http://www.benchmarksolutions.com/>
<image001.png>





<image001.png>


Nick West

Benchmark Solutions
101 Park Avenue - 7th Floor
New York, NY 10178
Tel +1.212.220.4739 | Mobile +1.646.267.4324
www.benchmarksolutions.com <http://www.benchmarksolutions.com/>
[cid:image001.png@01CCA50E.43B4A860]

Re: package-private methods in Vertex/BasicVertex

Posted by Alessandro Presta <al...@fb.com>.

Hi Nick,

Thanks for pointing this out.
Here's a relevant discussion that was just recently started: https://issues.apache.org/jira/browse/GIRAPH-272.
Hopefully we get this sorted out soon.

Alessandro

From: Nick West <ni...@benchmarksolutions.com>>
Reply-To: "user@giraph.apache.org<ma...@giraph.apache.org>" <us...@giraph.apache.org>>
Date: Wednesday, August 1, 2012 3:48 PM
To: "user@giraph.apache.org<ma...@giraph.apache.org>" <us...@giraph.apache.org>>
Subject: package-private methods in Vertex/BasicVertex

Hi,

There are several methods in Vertex/BasicVertex that are declared as abstract but without any access modifier specified.  They are:

    abstract void putMessages(Iterable<M> messages);
    abstract void releaseResources();

This has the effect that they both have the access modifier package-private.  The effect of this is that only classes in the giraph package that extend Vertex can override the method.  Specifically, any Vertex implementation not in the giraph package cannot override these methods.

Is this the intended behavior?  I think an easy fix would to be to explicitly declare them as protected, which would allow classes outside of the package to override these methods.

I've looked into using several of the other predefined vertex types (EdgeListVertex, HashMapVertex, etc), which override these methods. However, in these classes the write and readFields methods are declared final, limiting the amount of customization one can make to these classes.

If you have any alternative suggestions, I'd be happy to hear them.

Thanks,
Nick West

Benchmark Solutions
101 Park Avenue - 7th Floor
New York, NY 10178
Tel +1.212.220.4739 | Mobile +1.646.267.4324
www.benchmarksolutions.com <http://www.benchmarksolutions.com/>
[cid:image001.png@01CCA50E.43B4A860]