remove uneccessary casts

Author: mspruc

wayang-api/wayang-api-sql/src/main/java/org/apache/wayang/api/sql/calcite/converter/WayangAggregateVisitor.java

@@ -20,16 +20,15 @@
 
 import java.util.HashSet;
 import java.util.List;
-import java.util.Set;
 
-import org.apache.calcite.rel.core.Aggregate;
 import org.apache.calcite.rel.core.AggregateCall;
 
 import org.apache.wayang.api.sql.calcite.converter.functions.AggregateAddCols;
 import org.apache.wayang.api.sql.calcite.converter.functions.AggregateFunction;
 import org.apache.wayang.api.sql.calcite.converter.functions.AggregateKeyExtractor;
 import org.apache.wayang.api.sql.calcite.converter.functions.AggregateGetResult;
 import org.apache.wayang.api.sql.calcite.rel.WayangAggregate;
+
 import org.apache.wayang.basic.data.Record;
 import org.apache.wayang.basic.operators.GlobalReduceOperator;
 import org.apache.wayang.basic.operators.MapOperator;
@@ -49,7 +48,7 @@ public class WayangAggregateVisitor extends WayangRelNodeVisitor<WayangAggregate
     Operator visit(final WayangAggregate wayangRelNode) {
         final Operator childOp = wayangRelConverter.convert(wayangRelNode.getInput(0));
 
-        final List<AggregateCall> aggregateCalls = ((Aggregate) wayangRelNode).getAggCallList();
+        final List<AggregateCall> aggregateCalls = wayangRelNode.getAggCallList();
         final HashSet<Integer> groupingFields = new HashSet<>(wayangRelNode.getGroupSet().asSet());
 
         final MapOperator<Record, Record> mapOperator = new MapOperator<>(
@@ -76,6 +75,5 @@ Operator visit(final WayangAggregate wayangRelNode) {
                 Record.class);
         aggregateOperator.connectTo(0, mapOperator2, 0);
         return mapOperator2;
-
     }
 }

wayang-api/wayang-api-sql/src/main/java/org/apache/wayang/api/sql/calcite/converter/WayangFilterVisitor.java

@@ -38,8 +38,7 @@ public class WayangFilterVisitor extends WayangRelNodeVisitor<WayangFilter> {
     @Override
     Operator visit(final WayangFilter wayangRelNode) {
         final Operator childOp = wayangRelConverter.convert(wayangRelNode.getInput(0));
-
-        final RexNode condition = ((Filter) wayangRelNode).getCondition();
+        final RexNode condition = wayangRelNode.getCondition();
 
         final FilterOperator<Record> filter = new FilterOperator<>(
                 new FilterPredicateImpl(condition),