On 5/1/2012 10:19 PM, Eddie Epstein wrote:
Shahim,
That reference shows user code implementing the multithreaded wrapper around
core uima. Given that it would be [your] application code, you could stop after
instantiating one analysis engine, inspect the typesystem and update the
database schema before instantiating more AE. In this case it is all under
the control of the application code.
Note that UIMA-AS and the CPE do not synchronize access to an annotator
from different threads; they run multiple instances of an annotator in
different threads,
assuming that the user specifies that the annotator is thread safe by declaring
in the annotator's descriptor "MultipleInstancesAllowed=true".
Note that thread safe here means that it's OK to run multiple threads, each on
its own instance of the Annotator class. In practice this means that you have
to think about and insure thread safety only for "static" fields. Normal
instance fields will each have separate threads, and no thread safety issues
should arise for those.
Typically, the MultipleInstancesAllowed might be set to false in the case that
you wanted an annotator not to be replicated because in the flow, you wanted all
CASes to flow through it (it might be counting the CASes or accumulating some
other statistics over all the CASes).
-Marshall
Eddie
On Tue, May 1, 2012 at 3:03 PM, Shahim Essaid<[email protected]> wrote:
Hi Eddie,
I am new to UIMA so I might have to reread the documentation. I was
under the impression that I can use multiple threads as long as I use
a cas pool and a multi threaded AE. This is described here:
http://uima.apache.org/d/uimaj-2.4.0/tutorials_and_users_guides.html#ugr.tug.applications.multi_threaded
Did I misunderstand this part of the documentation? In my case I am
running Core UIMA and I would benefit from multitasking. (many of my
annotators have a lot of idle time waiting for responses from remote
servers)
This is my first time using UIMA and I have spent too much time trying
to persist the annotations in a database because I am frequently
changing my type system and experimenting with various analysis
approaches. Keeping the schema and INSERT statements in synch with the
type system was time consuming and error prone. I would like to
automate the persistence of the annotations based on the current type
system if possible. I was looking at Liquibase as an API that could be
used during the initialization of my pipelines to update the database
schema and then write a generic JDBC based annotator to write/insert
the cas to the database. Any thoughts?
Best,
Shahim
On Tue, May 1, 2012 at 10:54 AM, Eddie Epstein<[email protected]> wrote:
Core UIMA is a single-threaded framework. There are two multi-threaded
deployment wrappers, UIMA-AS and the older CPE. Are you using one of
these wrappers?
Eddie
On Mon, Apr 30, 2012 at 2:01 PM, Shahim Essaid<[email protected]> wrote:
Hi All,
I am trying to write a primitive analysis engine that checks, and
creates or updates a database schema based on the type system. I need
to synchronize the initialization of this component so that only one
instance of the component will do this task when there are multiple
instances being instantiated.
What is the correct object to synchronize on? Is the type system
object the correct one and does it maintain its identity throughout a
JVM run? Is it a different object in the other aggregates even though
they use the same type system description?
I need to block all other threads in the other instances of the
current component until the database is updated. I also need this
object to be specific to the current aggregate so that other
aggregates running in the same JVM can have their own synchronization
objects and database updates independent of each other. In other
words, I can't use a JVM wide object.
Thank you,
Shahim
