Delete call type from service relation. (#6)

* Add sum indicator operator and fixed a service relation columns factory bug.

* Delete call type from service relation.
diff --git a/oal-parser/src/main/java/org/apache/skywalking/oal/tool/parser/SourceColumnsFactory.java b/oal-parser/src/main/java/org/apache/skywalking/oal/tool/parser/SourceColumnsFactory.java
index c171290..6b2fce3 100644
--- a/oal-parser/src/main/java/org/apache/skywalking/oal/tool/parser/SourceColumnsFactory.java
+++ b/oal-parser/src/main/java/org/apache/skywalking/oal/tool/parser/SourceColumnsFactory.java
@@ -18,8 +18,7 @@
 
 package org.apache.skywalking.oal.tool.parser;
 
-import java.util.LinkedList;
-import java.util.List;
+import java.util.*;
 
 public class SourceColumnsFactory {
     public static List<SourceColumn> getColumns(String source) {
@@ -67,8 +66,6 @@
                 columnList.add(sourceService);
                 SourceColumn destService = new SourceColumn("destServiceId", "dest_service_id", int.class, true);
                 columnList.add(destService);
-                SourceColumn callType = new SourceColumn("callType", "call_type", int.class, true);
-                columnList.add(callType);
                 return columnList;
             case "ServiceInstanceRelation":
                 columnList = new LinkedList<>();
@@ -85,7 +82,7 @@
                 columnList = new LinkedList<>();
                 SourceColumn sourceEndpointColumn = new SourceColumn("endpointId", "endpoint_id", int.class, true);
                 columnList.add(sourceEndpointColumn);
-                SourceColumn childEndpointColumne  = new SourceColumn("childEndpointId", "child_endpoint_id", int.class, true);
+                SourceColumn childEndpointColumne = new SourceColumn("childEndpointId", "child_endpoint_id", int.class, true);
                 columnList.add(childEndpointColumne);
                 sourceService = new SourceColumn("serviceId", "service_id", int.class, false);
                 columnList.add(sourceService);
diff --git a/oal-parser/src/test/resources/oal_test.oal b/oal-parser/src/test/resources/oal_test.oal
index bbd1893..8a8ec03 100644
--- a/oal-parser/src/test/resources/oal_test.oal
+++ b/oal-parser/src/test/resources/oal_test.oal
@@ -22,7 +22,9 @@
 
 Service_Calls_Sum = from(Service.*).sum();
 
-Service_Relation_Calls_Sum = from(ServiceRelation.*).sum();
+Service_Relation_Client_Calls_Sum = from(ServiceRelation.*).filter(detectPoint == DetectPoint.CLIENT).sum();
+
+Service_Relation_Server_Calls_Sum = from(ServiceRelation.*).filter(detectPoint == DetectPoint.SERVER).sum();
 
 endpoint_Avg = from(Endpoint.latency).longAvg();