@Override
    public <T> List<T> list(QueryMetadata metadata, Map<Expression<?>, Iterable<?>> iterables,
            Expression<T> projection) {
        if (metadata.getJoins().size() == 1) {
            return evaluateSingleSource(metadata, iterables, false);
        } else {
            return evaluateMultipleSources(metadata, iterables, false);
        }
    }
Default implementation of the {@link QueryEngine} interface

@author tiwe
querydsl-collections/src/main/java/com/querydsl/collections/DefaultQueryEngine.java