feat: add new findRelationships interface and unit test placeholder (#…

…389)

* feat: add new findRelationships interface and unit test placeholder

* fix & nullable

dao-impl/ebean-dao/src/main/java/com/linkedin/metadata/dao/EbeanLocalRelationshipQueryDAO.java

@@ -164,6 +164,29 @@ public <SRC_SNAPSHOT extends RecordTemplate, DEST_SNAPSHOT extends RecordTemplat
         .collect(Collectors.toList());
   }
 
+  /**
+   * Finds a list of relationships of a specific type based on the given filters if applicable.
+   *
+   * @param sourceEntityUrn urn of the source entity to query
+   * @param sourceEntityFilter the filter to apply to the source entity when querying (not applicable to non-MG entities)
+   * @param destinationEntityUrn urn of the destination entity to query. If relationship is OwnedBy, this is crew/ldap.
+   * @param destinationEntityFilter the filter to apply to the destination entity when querying (not applicable to non-MG entities)
+   * @param relationshipType the type of relationship to query
+   * @param relationshipFilter the filter to apply to relationship when querying
+   * @param offset the offset query should start at. Ignored if set to a negative value.
+   * @param count the maximum number of entities to return. Ignored if set to a non-positive value.   * @return A list of relationship records.
+   */
+  @Nonnull
+  public <RELATIONSHIP extends RecordTemplate> List<RELATIONSHIP> findRelationships(
+      @Nullable String sourceEntityUrn, @Nullable LocalRelationshipFilter sourceEntityFilter,
+      @Nullable String destinationEntityUrn, @Nullable LocalRelationshipFilter destinationEntityFilter,
+      @Nonnull Class<RELATIONSHIP> relationshipType, @Nonnull LocalRelationshipFilter relationshipFilter,
+      int offset, int count) {
+    // NOTE: additional validation for sourceEntityUrn and sourceEntityUrn first.
+    // for non-MG entities, filters need to be null or ignored.
+    throw new RuntimeException("findRelationships is not implemented.");
+  }
+
   /**
    * Validate:
    * 1. The entity filter only contains supported condition.

dao-impl/ebean-dao/src/test/java/com/linkedin/metadata/dao/localrelationship/EbeanLocalRelationshipQueryDAOTest.java

@@ -271,6 +271,27 @@ public void testFindOneRelationshipWithFilter() throws Exception {
     assertEquals(consumeFromSamzaInNearline.size(), 1); // Because Samza only consumes kafka in NEARLINE.
   }
 
+  @Test
+  public void testFindOneRelationshipWithEntityUrn() {
+    // TODO: implement
+  }
+
+  @Test
+  public void testFindOneRelationshipWithFilterWithEntityUrn() {
+    // TODO: implement
+  }
+
+  @Test
+  public void testFindOneRelationshipWithNonMgEntityUrn() {
+    // TODO: implement
+  }
+
+  @Test
+  public void testFindOneRelationshipWithFilterWithNonMgEntityUrn() {
+    // TODO: implement
+    // non-MG entities should not support filter
+  }
+
   @Test
   public void testFindEntitiesOneHopAwayIncomingDirection() throws Exception {
     FooUrn alice = new FooUrn(1);