Re: [Simple-support] Beginner Question

[Graham S. <gr...@mo...>]

Thanks for the quick reply Niall.

Unfortunately it seems that the class attribute is not ignored by the
deserializer.

This works fine:

TaskInterface o = serializer.read(TaskInterface.class, "<task1
class=\"com.company.om.tasks.Task1\" a=\"14\" b=\"13\"/>");

But if I omit the class attribute then this:

TaskInterface o = serializer.read(TaskInterface.class, "<task1
a=\"14\" b=\"13\"/>");

will fail with

Exception in thread "main"
org.simpleframework.xml.load.InstantiationException: Cannot
instantiate interface com.company.om.tasks.TaskInterface
	at org.simpleframework.xml.load.ObjectFactory.getInstance(ObjectFactory.java:67)
	at org.simpleframework.xml.load.Composite.read(Composite.java:112)
	at org.simpleframework.xml.load.Traverser.read(Traverser.java:71)
	at org.simpleframework.xml.load.Persister.read(Persister.java:392)
	at org.simpleframework.xml.load.Persister.read(Persister.java:374)
	at org.simpleframework.xml.load.Persister.read(Persister.java:355)
	at org.simpleframework.xml.load.Persister.read(Persister.java:337)
	at org.simpleframework.xml.load.Persister.read(Persister.java:258)
	at com.somispo.processor.main.Main.main(Main.java:69)


I think that makes sense. If i've got a number of concrete classes
that implement the same interface, how would the deserializer know
which one to use without a fully qualified class name in the xml?

In any event the real problem I have is getting the serializer to
include the classname when i persist the object

regards,
Graham



On Tue, Jun 10, 2008 at 3:01 PM, Niall Gallagher
<gal...@ya...> wrote:
> Hi,
>
> The class attribute is a special attribute that is ignored by the deserialization. Can you use object.getClass().getName() ?
>
> Also you dont need to cast, the following.
>
> TaskInterface o = (TaskInterface) serializer.read(TaskInterface.class,
> serializedText);
>
> works as:
>
> TaskInterface o = serializer.read(TaskInterface.class,
> serializedText);
>
> Its casted by the class type TaskInterface.class, the return type is autocasted at compile time.
>
> Hope this helps,
> Niall
>
>
> --- On Tue, 6/10/08, Graham Stewart <gr...@mo...> wrote:
>
>> From: Graham Stewart <gr...@mo...>
>> Subject: [Simple-support] Beginner Question
>> To: sim...@li...
>> Date: Tuesday, June 10, 2008, 12:36 PM
>> First let me say that simple looks great - it's
>> refreshing to find a
>> java serialization tool that works without 5 megs of
>> dependencies!
>>
>>
>> I'm trying to use Simple in a situation very similar to
>> this tutorial example
>>
>> http://simple.sourceforge.net/download/stream/doc/tutorial/tutorial.php#override
>>
>> I have two classes that implement TaskInterface, Task1 and
>> Task2 and
>> i'd like to be able to serialize the TaskInterface and
>> get usable XML.
>>
>> Putting the class name in the xml seems to work and both of
>> these
>> deserialize fine:
>>
>> <task1 class="com.somispo.om.tasks.Task1"
>> a="14" b="13"/>
>> <task2 class="com.somispo.om.tasks.Task2"
>> c="15" d="16"/>
>>
>> TaskInterface o = (TaskInterface)
>> serializer.read(TaskInterface.class,
>> serializedText);
>>
>>
>> What I can't figure out is how to get that class
>> attribute in the xml
>> output from the Persister? It seems like it should be
>> straightforward,
>> but I can't get it to show when I try to persist a
>> TaskInterface.
>>
>> thanks,
>> Graham
>>
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>
>
>
>