Hi folks
> On 15. Dec 2018, at 13:41, Nicolas Paris <[email protected]> wrote:
>
> On Sat, Dec 15, 2018 at 07:20:33AM -0500, Alain Désilets wrote:
>> Is it possible to create dynamically typed annotations in UIMA? In other
>> words, would it be possible for users of my system to create a new type of
>> annotation without having to recompile the Java code?
My take on the problem is to redefine the CAS in-place. The following
code is used by the WebAnno annotation editor to handle the case where
the user modifies the type system:
---
/**
* Load the contents from the source CAS, upgrade it to the target type
system and write the
* results to the target CAS. An in-place upgrade can be achieved by using
the same CAS as
* source and target.
*/
private void upgradeCas(CAS aSourceCas, CAS aTargetCas,
TypeSystemDescription aTargetTypeSystem)
throws UIMAException, IOException
{
// Save source CAS type system (do this early since we might do an
in-place upgrade)
TypeSystem sourceTypeSystem = aSourceCas.getTypeSystem();
// Save source CAS contents
ByteArrayOutputStream serializedCasContents = new
ByteArrayOutputStream();
Serialization.serializeWithCompression(aSourceCas,
serializedCasContents, sourceTypeSystem);
// Re-initialize the target CAS with new type system
CAS tempCas = JCasFactory.createJCas(aTargetTypeSystem).getCas();
CASCompleteSerializer serializer =
Serialization.serializeCASComplete((CASImpl) tempCas);
Serialization.deserializeCASComplete(serializer, (CASImpl) aTargetCas);
// Leniently load the source CAS contents into the target CAS
CasIOUtils.load(new
ByteArrayInputStream(serializedCasContents.toByteArray()), aTargetCas,
sourceTypeSystem);
// Make sure JCas is properly initialized too
aTargetCas.getJCas();
}
---
This procedure takes a bit so it shouldn't be done often and also it discards
any non-reachable
feature structures - but it works. It also discards any information that is not
compatible with
the target type system - within any limits that lenient CAS loading may impose.
Basically you call it with
upgradeCas(aCas, aCas, aTargetTypeSystem);
in order to perform an in-place upgrade of a singla CAS to the given type
system.
Cheers,
-- Richard
