refactor: more direct access to VIATRA result set

Accessing VIATRA result sets through IQueryResultProvider requires a lot
of indirection, allocations, and locking.

We use reflection instead to have direct access to the underlying
Indexer instead.

Unfortunately, projection to arbitrary tuple masks (with wildcard
entries in a tuple) is completely broken in VIATRA when RETE update
propagation is delayed. While a new, ad-hoc projection indexer gets
added to the RETE net immediately, it is not populated with the
projection results until updates are flushed in the query engine.
Therefore, when encountering an ad-hoc projection for the first time,
the projection results will always be empty (thus usually out of date).

While declaring the desired projections ahead of time would be a
possible solution, for now, we completely remove ad-hoc projection
support. If projections are needed on the ModelQuery level, we should
create an API for declaring projections for each registered Dnf.

2 files changed, 5 insertions, 40 deletions

diff --git a/subprojects/store-query/src/main/java/tools/refinery/store/query/EmptyResultSet.java b/subprojects/store-query/src/main/java/tools/refinery/store/query/EmptyResultSet.java
index a01a5a2f..0c2e07d6 100644
--- a/subprojects/store-query/src/main/java/tools/refinery/store/query/EmptyResultSet.java
+++ b/subprojects/store-query/src/main/java/tools/refinery/store/query/EmptyResultSet.java
@@ -1,49 +1,22 @@
 package tools.refinery.store.query;
 
-import tools.refinery.store.tuple.Tuple;
 import tools.refinery.store.tuple.TupleLike;
 
-import java.util.Optional;
 import java.util.stream.Stream;
 
 public class EmptyResultSet implements ResultSet {
         @Override
-        public boolean hasResult() {
+        public boolean hasResult(TupleLike parameters) {
                 return false;
         }
 
         @Override
-        public boolean hasResult(Tuple parameters) {
-                return false;
-        }
-
-        @Override
-        public Optional<TupleLike> oneResult() {
-                return Optional.empty();
-        }
-
-        @Override
-        public Optional<TupleLike> oneResult(Tuple parameters) {
-                return Optional.empty();
-        }
-
-        @Override
         public Stream<TupleLike> allResults() {
                 return Stream.of();
         }
 
         @Override
-        public Stream<TupleLike> allResults(Tuple parameters) {
-                return Stream.of();
-        }
-
-        @Override
         public int countResults() {
                 return 0;
         }
-
-        @Override
-        public int countResults(Tuple parameters) {
-                return 0;
-        }
 }
diff --git a/subprojects/store-query/src/main/java/tools/refinery/store/query/ResultSet.java b/subprojects/store-query/src/main/java/tools/refinery/store/query/ResultSet.java
index 3542e252..407cf075 100644
--- a/subprojects/store-query/src/main/java/tools/refinery/store/query/ResultSet.java
+++ b/subprojects/store-query/src/main/java/tools/refinery/store/query/ResultSet.java
@@ -1,25 +1,17 @@
 package tools.refinery.store.query;
 
-import tools.refinery.store.tuple.Tuple;
 import tools.refinery.store.tuple.TupleLike;
 
-import java.util.Optional;
 import java.util.stream.Stream;
 
 public interface ResultSet {
-        boolean hasResult();
+        default boolean hasResult() {
+                return countResults() > 0;
+        }
 
-        boolean hasResult(Tuple parameters);
-
-        Optional<TupleLike> oneResult();
-
-        Optional<TupleLike> oneResult(Tuple parameters);
+        boolean hasResult(TupleLike parameters);
 
         Stream<TupleLike> allResults();
 
-        Stream<TupleLike> allResults(Tuple parameters);
-
         int countResults();
-
-        int countResults(Tuple parameters);
 }