Added filter conversion and unit test

Author: rutvij-menavlikar

config-service-impl/src/main/java/org/hypertrace/config/service/store/FilterBuilder.java

@@ -92,6 +92,14 @@ private Filter evaluateLeafExpression(RelationalFilter relationalFilter) {
       case RELATIONAL_OPERATOR_GTE:
         return new Filter(
             Filter.Op.GTE, buildConfigFieldPath(relationalFilter.getConfigJsonPath()), value);
+      case RELATIONAL_OPERATOR_EXISTS:
+        return new Filter(
+            Filter.Op.EXISTS, buildConfigFieldPath(relationalFilter.getConfigJsonPath()), value);
+      case RELATIONAL_OPERATOR_NOT_EXISTS:
+        return new Filter(
+            Filter.Op.NOT_EXISTS,
+            buildConfigFieldPath(relationalFilter.getConfigJsonPath()),
+            value);
       case UNRECOGNIZED:
       default:
         throw Status.INVALID_ARGUMENT

config-service-impl/src/test/java/org/hypertrace/config/service/store/FilterBuilderTest.java

@@ -83,6 +83,41 @@ void buildDocStoreFilter2() {
     assertEquals(docFilter.toString(), filterBuilder.buildDocStoreFilter(filter).toString());
   }
 
+  @Test
+  void testExistsAndNotExistsOperators() {
+    // Test EXISTS operator
+    Filter existsFilter =
+        Filter.newBuilder()
+            .setRelationalFilter(
+                RelationalFilter.newBuilder()
+                    .setConfigJsonPath("testField")
+                    .setOperator(RelationalOperator.RELATIONAL_OPERATOR_EXISTS))
+            .build();
+
+    org.hypertrace.core.documentstore.Filter expectedExistsFilter =
+        new org.hypertrace.core.documentstore.Filter(
+            org.hypertrace.core.documentstore.Filter.Op.EXISTS, "config.testField", null);
+    assertEquals(
+        expectedExistsFilter.toString(),
+        filterBuilder.buildDocStoreFilter(existsFilter).toString());
+
+    // Test NOT_EXISTS operator
+    Filter notExistsFilter =
+        Filter.newBuilder()
+            .setRelationalFilter(
+                RelationalFilter.newBuilder()
+                    .setConfigJsonPath("anotherField")
+                    .setOperator(RelationalOperator.RELATIONAL_OPERATOR_NOT_EXISTS))
+            .build();
+
+    org.hypertrace.core.documentstore.Filter expectedNotExistsFilter =
+        new org.hypertrace.core.documentstore.Filter(
+            org.hypertrace.core.documentstore.Filter.Op.NOT_EXISTS, "config.anotherField", null);
+    assertEquals(
+        expectedNotExistsFilter.toString(),
+        filterBuilder.buildDocStoreFilter(notExistsFilter).toString());
+  }
+
   @Test
   void buildDocStoreFilter3() {
     Filter filter =