Examples with ExpressionNaming org.immutables.criteria.backend.ExpressionNaming used on opensource projects

Example 1 with ExpressionNaming

use of org.immutables.criteria.backend.ExpressionNaming in project immutables by immutables.

the class MongoSession method query.

private Publisher<?> query(StandardOperations.Select select) {
    final Query query = select.query();
    final boolean hasProjections = query.hasProjections();
    boolean useAggregationPipeline = query.hasAggregations() || query.distinct() || query.count() && query.limit().isPresent();
    ExpressionNaming expressionNaming = useAggregationPipeline ? ExpressionNaming.from(UniqueCachedNaming.of(query.projections())) : expression -> pathNaming.name((Path) expression);
    MongoCollection<?> collection = this.collection;
    if (hasProjections) {
        // add special TupleCodecProvider for projections
        CodecRegistry newRegistry = CodecRegistries.fromRegistries(this.collection.getCodecRegistry(), CodecRegistries.fromProviders(new TupleCodecProvider(query, expressionNaming)));
        collection = this.collection.withDocumentClass(ProjectedTuple.class).withCodecRegistry(newRegistry);
    }
    if (useAggregationPipeline) {
        // aggregations
        AggregationQuery agg = new AggregationQuery(query, pathNaming);
        if (query.count()) {
            // also for empty result-set mongo does not return single(0) but empty publisher
            return Flowable.fromPublisher(collection.aggregate(agg.toPipeline(), BsonDocument.class)).map(d -> d.get("count").asNumber().longValue()).defaultIfEmpty(// return Single.just(0) for empty publisher
            0L);
        }
        return collection.aggregate(agg.toPipeline(), ProjectedTuple.class);
    }
    Bson filter = toBsonFilter(query);
    if (query.count()) {
        // simple form of count all (without distinct, aggregations etc.) : count(*)
        return Flowable.fromPublisher(collection.countDocuments(filter));
    }
    final FindPublisher<?> find = collection.find(filter);
    if (!query.collations().isEmpty()) {
        // add sorting
        final Function<Collation, Bson> toSortFn = col -> {
            final String path = col.path().toStringPath();
            return col.direction().isAscending() ? Sorts.ascending(path) : Sorts.descending(path);
        };
        final List<Bson> sorts = query.collations().stream().map(toSortFn).collect(Collectors.toList());
        find.sort(Sorts.orderBy(sorts));
    }
    query.limit().ifPresent(limit -> find.limit((int) limit));
    query.offset().ifPresent(offset -> find.skip((int) offset));
    if (hasProjections) {
        List<String> fields = query.projections().stream().map(p -> pathNaming.name((Path) p)).collect(Collectors.toList());
        find.projection(Projections.include(fields));
        return find;
    }
    // post-process result with projections
    return find;
}