adding order by

gateway-service-impl/src/main/java/org/hypertrace/gateway/service/common/converters/EntityServiceAndGatewayServiceConverter.java

@@ -11,6 +11,7 @@
 import org.hypertrace.entity.query.service.v1.ColumnMetadata;
 import org.hypertrace.entity.query.service.v1.EntityQueryRequest;
 import org.hypertrace.entity.query.service.v1.Expression;
+import org.hypertrace.entity.query.service.v1.Expression.Builder;
 import org.hypertrace.entity.query.service.v1.Filter;
 import org.hypertrace.entity.query.service.v1.Function;
 import org.hypertrace.entity.query.service.v1.LiteralConstant;
@@ -133,6 +134,19 @@ public static Operator convertOperator(
     return Operator.valueOf(operator.name());
   }
 
+  public static OrderByExpression.Builder convertToEntityServiceOrderByExpression(
+      org.hypertrace.gateway.service.v1.common.OrderByExpression orderByExpression) {
+    Builder expressionBuilder = convertToEntityServiceExpression(orderByExpression.getExpression());
+    return OrderByExpression.newBuilder()
+        .setExpression(expressionBuilder)
+        .setOrder(convertToEntityServiceSortOrder(orderByExpression.getOrder()));
+  }
+
+  public static SortOrder convertToEntityServiceSortOrder(
+      org.hypertrace.gateway.service.v1.common.SortOrder sortOrder) {
+    return SortOrder.valueOf(sortOrder.name());
+  }
+
   public static Expression.Builder convertToEntityServiceExpression(
       org.hypertrace.gateway.service.v1.common.Expression expression) {
     Expression.Builder builder = Expression.newBuilder();

gateway-service-impl/src/main/java/org/hypertrace/gateway/service/explore/entity/EntityServiceEntityFetcher.java

@@ -167,12 +167,24 @@ private EntityQueryRequest buildRequest(
             .setFilter(buildFilter(exploreRequest, entityIdAttributeIds, entityIds));
 
     addGroupBys(exploreRequest, builder);
+    addSortBy(exploreRequest, builder);
     addSelections(requestContext, exploreRequest, builder);
     builder.setLimit(exploreRequest.getLimit());
     builder.setOffset(exploreRequest.getOffset());
     return builder.build();
   }
 
+  private void addSortBy(ExploreRequest exploreRequest, EntityQueryRequest.Builder builder) {
+    List<org.hypertrace.gateway.service.v1.common.OrderByExpression> orderBys =
+        exploreRequest.getOrderByList();
+    orderBys.forEach(
+        orderBy ->
+            builder.addOrderBy(
+                EntityServiceAndGatewayServiceConverter.convertToEntityServiceOrderByExpression(
+                        orderBy)
+                    .build()));
+  }
+
   private void addGroupBys(ExploreRequest exploreRequest, EntityQueryRequest.Builder builder) {
     List<org.hypertrace.gateway.service.v1.common.Expression> groupBys =
         ExpressionReader.getAttributeExpressions(exploreRequest.getGroupByList());