[infinispan-dev] Preliminary implementation for ISPN-244 and improvement suggestions.

Thu Dec 9 07:31:05 EST 2010

On Dec 8, 2010, at 10:05 PM, Mircea Markus wrote:

> 
> On 8 Dec 2010, at 08:49, Galder Zamarreño wrote:
> 
>> 
>> On Dec 7, 2010, at 7:16 PM, Sanne Grinovero wrote:
>> 
>>> Hi,
>>> Is the Clazz going to be matched with some degree of polymorphism?
>> 
>> No, it'll be matched on equality, so no polymorphism there.
>> 
>>> Or will I be able to use the same externaliser for multiple types, so
>>> effectively having something like
>>> 
>>> marshallable.setTypeClasses(Class... types)
>>> 
>>> and
>>> @Marshalls(typeClasses={Person.class}, id=768)
>> 
>> That could certainly be handy. Good suggestion Sanne :). It's not uncommon to see the same Externalizer type being used for different classes. For example, within Infinispan you have:
>> 
>>     JDK_EXTERNALIZERS.put(HashMap.class.getName(), MapExternalizer.class.getName());
>>     JDK_EXTERNALIZERS.put(TreeMap.class.getName(), MapExternalizer.class.getName());
> Isn't this possible even now through XML?
> <marshallable id="456" typeClass="com.acme.Person"  externalizerClass="com.acme.SameExternalizer"/>
> <marshallable id="457" typeClass="com.acme.HotPerson"  externalizerClass="com.acme.SameExternalizer"/>

Yeah, that was already possible. I was just saying that his suggestions for setTypeClasses() API and @Marshalls annotation would be useful.

>> 
>> Where MapExternalizer externalizes both HashMap and TreeMap.
>> 
>>> 
>>> Cheers,
>>> Sanne
>>> 
>>> 2010/12/7 Manik Surtani <manik at jboss.org>:
>>>> All looks great.  +1 to annotating externalizers rather than the class being externalized, but how would you match them up?  When the marshalling framework sees Class clazz, would it try and match the classes using clazz.equals()?  We'd need to consider class loader implications...
>>>> 
>>>> +1 to making the config easier too.
>>>> 
>>>> 
>>>> On 7 Dec 2010, at 09:49, Galder Zamarreño wrote:
>>>> 
>>>>> Hi all,
>>>>> 
>>>>> Re: https://jira.jboss.org/browse/ISPN-244
>>>>> 
>>>>> This is trunk now and I've written preliminary documentation for it in http://community.jboss.org/docs/DOC-16198. Have a read through it and let me know what you think.
>>>>> 
>>>>> Now, there's a couple of improvements I'm considering doing even for alpha1:
>>>>> 
>>>>> 1. Internally, Infinispan has been mapping Externalizer classes and the types they marshall via @Marshallable interface. I don't think this annotation is really usable as it is for users cos there can be situations where users might not be able to modify the class that they wanna serialize. However, they for sure should be able to modify the Externalizer implementation classes, so I was wondering of converting this annotation into an annotation that an Externalizer class takes and that specifies the type of class that it externalizes and its id. Example:
>>>>> 
>>>>> class Person {
>>>>> ...
>>>>> }
>>>>> 
>>>>> @Marshalls(typeClass=Person.class, id=768)
>>>>> class PersonExternalizer Implements Externalizer<Person> {
>>>>> ...
>>>>> }
>>>>> 
>>>>> This could be a mechanism that could be used in equal manner by both internal and user defined externalizers. We don't wanna be doing annotation scanning, so in the same fashion that for internal externalizers we list the type classes that can be extermalized, this could lead to a user configuration simplification, i.e:
>>>>> 
>>>>> <global>
>>>>> <serialization>
>>>>>  <externalizers>
>>>>>    <externalizer class="PersonExternalizer" />
>>>>>  </externalizers>
>>>>> </serialization>
>>>>> </global>
>>>>> 
>>>>> On startup we'd load the externalizers defined in configuration and search for the @Marshalls annotation which would give us the rest of info which is: typeClass and id. Thoughts?? I think this would make internal and user defined externalizers more homogeneous when it comes to their definition and would simplify configuration.
>>>>> 
>>>>> Chaging @Marshallable to @Marshalls should be easy to do particularly cos this annotation was only used for internal purpouses.
>>>>> 
>>>>> 2. The second improvement I had in mind is around programmatic configuration. As you can see in the docu, configuring programmatically user defined externalizers requires quite a bit of code. I was thinking of adding a helper method in global configuration that would hide all of that away. If you take in account my recommendations for the previous point, that would be limited to something along the lines of:
>>>>> 
>>>>> globalCfg.addExternalizer(PersonExternalizer.class);
>>>>> 
>>>>> Where the method would have a signature like: public void addExternalizer(Class<? externds Externalizer> externalizerClass);
>>>>> 
>>>>> We could also have an alternative that uses reflection to load the class and add it: public void addExternalizer(String externalizerClassName);
>>>>> 
>>>>> Cheers,
>>>>> --
>>>>> Galder Zamarreño
>>>>> Sr. Software Engineer
>>>>> Infinispan, JBoss Cache
>>>>> 
>>>>> 
>>>>> _______________________________________________
>>>>> infinispan-dev mailing list
>>>>> infinispan-dev at lists.jboss.org
>>>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>>> 
>>>> --
>>>> Manik Surtani
>>>> manik at jboss.org
>>>> Lead, Infinispan
>>>> Lead, JBoss Cache
>>>> http://www.infinispan.org
>>>> http://www.jbosscache.org
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
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>>>> 
>>> 
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>> 
>> --
>> Galder Zamarreño
>> Sr. Software Engineer
>> Infinispan, JBoss Cache
>> 
>> 
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--
Galder Zamarreño
Sr. Software Engineer
Infinispan, JBoss Cache