FilterablePageableDataProvider does not work in Vaadin Bakery demo

[jcgueriaud1]

If you try to filter the combobox in the order editor in the Bakery Demo. The combobox is not filtered.

If you add a breakpoint in FilterablePageableDataProvider in fetch(Query<T, F> query).

The query filter is set but it's ignored.

 private Query<T, F> getFilterQuery(Query<T, F> t) {
        return new Query(t.getOffset(), t.getLimit(), t.getSortOrders(), t.getInMemorySorting(), this.filter);
    }

See the forum post here: https://vaadin.com/forum/thread/18354860/combo-boxes-not-filtering-as-expected

[jcoleman-scott]

In my use case the filter is empty. It appears the ComboBox doesn't pass it at all; I assume this is because the ComboBox has been set up to do client-side filtering based on how it was constructed?

[jcgueriaud1]

The combobox never called setFilter of the FilterablePageableDataProvider and FilterablePageableDataProvider does not use the query filter given by the combobox.
If you change the FilterablePageableDataProvider to this:

package org.vaadin.artur.spring.dataprovider;

import com.vaadin.flow.data.provider.Query;
import java.util.Optional;
import java.util.stream.Stream;

public abstract class FilterablePageableDataProvider<T, F> extends PageableDataProvider<T, F> {
    private F filter = null;

    public FilterablePageableDataProvider() {
    }

    public void setFilter(F filter) {
        if (filter == null) {
            throw new IllegalArgumentException("Filter cannot be null");
        } else {
            this.filter = filter;
            this.refreshAll();
        }
    }

    public int size(Query<T, F> query) {
        return super.size(this.getFilterQuery(query));
    }

    public Stream<T> fetch(Query<T, F> query) {
        return super.fetch(this.getFilterQuery(query));
    }

    private Query<T, F> getFilterQuery(Query<T, F> t) {
       /// Use the query filter if it exists else use the external filter
        F filter = t.getFilter().orElse(this.filter);
        return new Query(t.getOffset(), t.getLimit(), t.getSortOrders(), t.getInMemorySorting(), filter);
    }

    protected Optional<F> getOptionalFilter() {
        return this.filter == null ? Optional.empty() : Optional.of(this.filter);
    }
}

The filtering is working.

I'm not sure if my fix is the right one, but I think the problem is not related to the combobox.