Re: ObjectSelect to select uncommitted objects

There isn't anything built-in. I use this method in my own DataContext
subclass to do it. Use at your own risk, etc.

*public* <T *extends* Persistent> List<T>
selectIncludingPendingChanges(ObjectSelect<T> query) {

Set<Object> newAndModified = *new* HashSet<>(newObjects());

newAndModified.addAll(modifiedObjects());

Set<T> inMemoryResults = newAndModified.stream()

.filter(o -> o.getClass().equals(query.getEntityType()))

.filter(o -> query.getWhere().match(o))

.map(o -> (T)o)

.collect(Collectors.*toSet*());

List<T> dbResults = select(query);

dbResults.removeAll(newAndModified); // these have already been checked

dbResults.removeAll(deletedObjects());

*if* (inMemoryResults.isEmpty()) {

*return* dbResults; // performance optimization

}

inMemoryResults.addAll(dbResults); // combines and removes duplicates

List<T> results = *new* ArrayList<>(inMemoryResults);

*if* (query.getOrderings() != *null* && !query.getOrderings().isEmpty()) {

Ordering.*orderList*(results, *new* ArrayList<>(query.getOrderings()));

}

*if* (query.getLimit() > 0) {

results = results.subList(0, query.getLimit());

}

*return* (List<T>) results;

}


*public* *static* *class* Factory *extends* DataContextFactory {

@Override

*protected* MyDataContext newInstance(DataChannel parent, ObjectStore
objectStore) {

*return* *new* MyDataContext(parent, objectStore);

}

}


*public* *static* *final* Module *MODULE* = binder ->

binder.bind(ObjectContextFactory.*class*).to(MyDataContext.Factory.*class*);



On Sat, Nov 14, 2020 at 10:20 AM [email protected] <
[email protected]> wrote:

> Hello,
>
> I have multiple places where I have to search data either on the current
> ObjectStore (newly inserted or modified objects) or directly in the DB.
>
> At the moment I have two distinct blocks of code, one expressed as a
> Predicate (used inside a stream filter) and the other with an ObjectSelect
> (on which I call its select method).
>
> As both structure encode the same "logic" criteria, it would be nice to be
> able to derive one from the other.
>
> One way to solve this would be to be able to transform on ObjectSelect
> instance into a Predicate instance.
> Or, the ability to run an ObjectSelect not only on the DB, but also into
> the uncommitted objects in the ObjectContext.
>
> Is there anything I am missing that could help me dealing with this need?
>
> Cheers,
>
> Giulio Cesare
>