add support for facets

Author: agourlay

src/main/java/io/qdrant/client/QdrantClient.java

@@ -2805,6 +2805,37 @@ public ListenableFuture<List<PointGroup>> queryGroupsAsync(
         future, response -> response.getResult().getGroupsList(), MoreExecutors.directExecutor());
   }
 
+  /**
+   * Perform facet counts. For each value in the field, count the number of points that have this
+   * value and match the conditions.
+   *
+   * @param request the facet counts request
+   * @return a new instance of {@link ListenableFuture}
+   */
+  public ListenableFuture<List<Points.FacetHit>> facetAsync(Points.FacetCounts request) {
+    return facetAsync(request, null);
+  }
+
+  /**
+   * Perform facet counts. For each value in the field, count the number of points that have this
+   * value and match the conditions.
+   *
+   * @param request the facet counts request
+   * @param timeout the timeout for the call.
+   * @return a new instance of {@link ListenableFuture}
+   */
+  public ListenableFuture<List<Points.FacetHit>> facetAsync(
+      Points.FacetCounts request, @Nullable Duration timeout) {
+    Preconditions.checkArgument(
+        !request.getCollectionName().isEmpty(), "Collection name must not be empty");
+
+    logger.debug("Facet on '{}'", request.getCollectionName());
+    ListenableFuture<Points.FacetResponse> future = getPoints(timeout).facet(request);
+    addLogFailureCallback(future, "Facet");
+    return Futures.transform(
+        future, Points.FacetResponse::getHitsList, MoreExecutors.directExecutor());
+  }
+
   // region distance matrix
 
   /**

src/test/java/io/qdrant/client/PointsTest.java

@@ -849,6 +849,44 @@ public void searchMatrixPairs() throws ExecutionException, InterruptedException
     assertEquals(2, pairs.getPairsCount());
   }
 
+  @Test
+  public void facets() throws ExecutionException, InterruptedException {
+    createAndSeedCollection(testName);
+
+    // create payload index for "foo" field
+    UpdateResult result =
+        client
+            .createPayloadIndexAsync(
+                testName, "foo", PayloadSchemaType.Keyword, null, null, null, null)
+            .get();
+
+    assertEquals(UpdateStatus.Completed, result.getStatus());
+
+    List<Points.FacetHit> facets =
+        client
+            .facetAsync(
+                Points.FacetCounts.newBuilder()
+                    .setCollectionName(testName)
+                    .setKey("foo")
+                    .setLimit(2)
+                    .build())
+            .get();
+
+    // Number of facets matches the limit
+    assertEquals(2, facets.size());
+    // validate hits
+    assertEquals(
+        1,
+        facets.stream()
+            .filter(f -> f.getValue().getStringValue().equals("hello") && f.getCount() == 1)
+            .count());
+    assertEquals(
+        1,
+        facets.stream()
+            .filter(f -> f.getValue().getStringValue().equals("goodbye") && f.getCount() == 1)
+            .count());
+  }
+
   private void createAndSeedCollection(String collectionName)
       throws ExecutionException, InterruptedException {
     CreateCollection request =