[CALCITE-4838] Add RoundingMode in RelDataTypeSystem to specify the r…

…ounding behavior

core/src/main/java/org/apache/calcite/adapter/enumerable/RexToLixTranslator.java

@@ -456,45 +456,51 @@ private Expression getConvertExpression(
           && scale != RelDataType.SCALE_NOT_SPECIFIED) {
         if (sourceType.getFamily() == SqlTypeFamily.CHARACTER) {
           return Expressions.call(
-              BuiltInMethod.CHAR_DECIMAL_CAST.method,
+              BuiltInMethod.CHAR_DECIMAL_CAST_ROUNDING_MODE.method,
               operand,
               Expressions.constant(precision),
-              Expressions.constant(scale));
+              Expressions.constant(scale),
+              Expressions.constant(typeFactory.getTypeSystem().roundingMode()));
         } else if (sourceType.getFamily() == SqlTypeFamily.INTERVAL_DAY_TIME) {
           return Expressions.call(
-              BuiltInMethod.SHORT_INTERVAL_DECIMAL_CAST.method,
+              BuiltInMethod.SHORT_INTERVAL_DECIMAL_CAST_ROUNDING_MODE.method,
               operand,
               Expressions.constant(precision),
               Expressions.constant(scale),
-              Expressions.constant(sourceType.getSqlTypeName().getEndUnit().multiplier));
+              Expressions.constant(sourceType.getSqlTypeName().getEndUnit().multiplier),
+              Expressions.constant(typeFactory.getTypeSystem().roundingMode()));
         } else if (sourceType.getFamily() == SqlTypeFamily.INTERVAL_YEAR_MONTH) {
           return Expressions.call(
-              BuiltInMethod.LONG_INTERVAL_DECIMAL_CAST.method,
+              BuiltInMethod.LONG_INTERVAL_DECIMAL_CAST_ROUNDING_MODE.method,
               operand,
               Expressions.constant(precision),
               Expressions.constant(scale),
-              Expressions.constant(sourceType.getSqlTypeName().getEndUnit().multiplier));
+              Expressions.constant(sourceType.getSqlTypeName().getEndUnit().multiplier),
+              Expressions.constant(typeFactory.getTypeSystem().roundingMode()));
         } else if (sourceType.getSqlTypeName() == SqlTypeName.DECIMAL) {
           // Cast from DECIMAL to DECIMAL, may adjust scale and precision.
           return Expressions.call(
-              BuiltInMethod.DECIMAL_DECIMAL_CAST.method,
+              BuiltInMethod.DECIMAL_DECIMAL_CAST_ROUNDING_MODE.method,
               operand,
               Expressions.constant(precision),
-              Expressions.constant(scale));
+              Expressions.constant(scale),
+              Expressions.constant(typeFactory.getTypeSystem().roundingMode()));
         } else if (SqlTypeName.INT_TYPES.contains(sourceType.getSqlTypeName())) {
           // Cast from INTEGER to DECIMAL, check for overflow
           return Expressions.call(
-              BuiltInMethod.INTEGER_DECIMAL_CAST.method,
+              BuiltInMethod.INTEGER_DECIMAL_CAST_ROUNDING_MODE.method,
               operand,
               Expressions.constant(precision),
-              Expressions.constant(scale));
+              Expressions.constant(scale),
+              Expressions.constant(typeFactory.getTypeSystem().roundingMode()));
         }  else if (SqlTypeName.APPROX_TYPES.contains(sourceType.getSqlTypeName())) {
           // Cast from FLOAT/DOUBLE to DECIMAL
           return Expressions.call(
-              BuiltInMethod.FP_DECIMAL_CAST.method,
+              BuiltInMethod.FP_DECIMAL_CAST_ROUNDING_MODE.method,
               operand,
               Expressions.constant(precision),
-              Expressions.constant(scale));
+              Expressions.constant(scale),
+              Expressions.constant(typeFactory.getTypeSystem().roundingMode()));
         }
       }
       return defaultExpression.get();
@@ -505,9 +511,9 @@ private Expression getConvertExpression(
     case SMALLINT: {
       if (SqlTypeName.NUMERIC_TYPES.contains(sourceType.getSqlTypeName())) {
         return Expressions.call(
-            BuiltInMethod.INTEGER_CAST.method,
+            BuiltInMethod.INTEGER_CAST_ROUNDING_MODE.method,
             Expressions.constant(Primitive.of(typeFactory.getJavaClass(targetType))),
-            operand);
+            operand, Expressions.constant(typeFactory.getTypeSystem().roundingMode()));
       }
       return defaultExpression.get();
     }

core/src/main/java/org/apache/calcite/rel/type/DelegatingTypeSystem.java

@@ -20,6 +20,8 @@
 
 import org.checkerframework.checker.nullness.qual.Nullable;
 
+import java.math.RoundingMode;
+
 /** Implementation of {@link org.apache.calcite.rel.type.RelDataTypeSystem}
  * that sends all methods to an underlying object. */
 public class DelegatingTypeSystem implements RelDataTypeSystem {
@@ -50,6 +52,10 @@ protected DelegatingTypeSystem(RelDataTypeSystem typeSystem) {
     return typeSystem.getMaxNumericPrecision();
   }
 
+  @Override public RoundingMode roundingMode() {
+    return typeSystem.roundingMode();
+  }
+
   @Override public @Nullable String getLiteral(SqlTypeName typeName, boolean isPrefix) {
     return typeSystem.getLiteral(typeName, isPrefix);
   }

core/src/main/java/org/apache/calcite/rel/type/RelDataTypeSystem.java

@@ -22,6 +22,8 @@
 
 import org.checkerframework.checker.nullness.qual.Nullable;
 
+import java.math.RoundingMode;
+
 /**
  * Type system.
  *
@@ -60,6 +62,9 @@ public interface RelDataTypeSystem {
   /** Returns the maximum precision of a NUMERIC or DECIMAL type. */
   int getMaxNumericPrecision();
 
+  /** Returns the rounding behavior for numerical operations capable of discarding precision. */
+  RoundingMode roundingMode();
+
   /** Returns the LITERAL string for the type, either PREFIX/SUFFIX. */
   @Nullable String getLiteral(SqlTypeName typeName, boolean isPrefix);
 

core/src/main/java/org/apache/calcite/rel/type/RelDataTypeSystemImpl.java

@@ -22,6 +22,8 @@
 
 import org.checkerframework.checker.nullness.qual.Nullable;
 
+import java.math.RoundingMode;
+
 /** Default implementation of
  * {@link org.apache.calcite.rel.type.RelDataTypeSystem},
  * providing parameters from the SQL standard.
@@ -160,6 +162,10 @@ public abstract class RelDataTypeSystemImpl implements RelDataTypeSystem {
     return 19;
   }
 
+  @Override public RoundingMode roundingMode() {
+    return RoundingMode.DOWN;
+  }
+
   @Override public @Nullable String getLiteral(SqlTypeName typeName, boolean isPrefix) {
     switch (typeName) {
     case VARBINARY:

core/src/main/java/org/apache/calcite/util/BuiltInMethod.java

@@ -125,6 +125,7 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.math.BigDecimal;
+import java.math.RoundingMode;
 import java.nio.charset.Charset;
 import java.sql.ResultSet;
 import java.sql.Time;
@@ -159,10 +160,16 @@ public enum BuiltInMethod {
   AS_QUERYABLE(Enumerable.class, "asQueryable"),
   ABSTRACT_ENUMERABLE_CTOR(AbstractEnumerable.class),
   CHAR_DECIMAL_CAST(Primitive.class, "charToDecimalCast", String.class, int.class, int.class),
+  CHAR_DECIMAL_CAST_ROUNDING_MODE(Primitive.class, "charToDecimalCast",
+      String.class, int.class, int.class, RoundingMode.class),
   SHORT_INTERVAL_DECIMAL_CAST(Primitive.class, "shortIntervalToDecimalCast",
       Long.class, int.class, int.class, BigDecimal.class),
+  SHORT_INTERVAL_DECIMAL_CAST_ROUNDING_MODE(Primitive.class, "shortIntervalToDecimalCast",
+      Long.class, int.class, int.class, BigDecimal.class, RoundingMode.class),
   LONG_INTERVAL_DECIMAL_CAST(Primitive.class, "longIntervalToDecimalCast",
       Integer.class, int.class, int.class, BigDecimal.class),
+  LONG_INTERVAL_DECIMAL_CAST_ROUNDING_MODE(Primitive.class, "longIntervalToDecimalCast",
+      Integer.class, int.class, int.class, BigDecimal.class, RoundingMode.class),
   INTO(ExtendedEnumerable.class, "into", Collection.class),
   REMOVE_ALL(ExtendedEnumerable.class, "removeAll", Collection.class),
   SCHEMA_GET_SUB_SCHEMA(Schema.class, "getSubSchema", String.class),
@@ -310,11 +317,17 @@ public enum BuiltInMethod {
   AS_LIST(Primitive.class, "asList", Object.class),
   DECIMAL_DECIMAL_CAST(Primitive.class, "decimalDecimalCast",
       BigDecimal.class, int.class, int.class),
-  INTEGER_DECIMAL_CAST(Primitive.class, "integerDecimalCast",
-      Number.class, int.class, int.class),
-  FP_DECIMAL_CAST(Primitive.class, "fpDecimalCast",
-      Number.class, int.class, int.class),
+  DECIMAL_DECIMAL_CAST_ROUNDING_MODE(Primitive.class, "decimalDecimalCast",
+      BigDecimal.class, int.class, int.class, RoundingMode.class),
+  INTEGER_DECIMAL_CAST(Primitive.class, "integerDecimalCast", Number.class, int.class, int.class),
+  INTEGER_DECIMAL_CAST_ROUNDING_MODE(Primitive.class, "integerDecimalCast",
+      Number.class, int.class, int.class, RoundingMode.class),
+  FP_DECIMAL_CAST(Primitive.class, "fpDecimalCast", Number.class, int.class, int.class),
+  FP_DECIMAL_CAST_ROUNDING_MODE(Primitive.class, "fpDecimalCast",
+      Number.class, int.class, int.class, RoundingMode.class),
   INTEGER_CAST(Primitive.class, "integerCast", Primitive.class, Object.class),
+  INTEGER_CAST_ROUNDING_MODE(Primitive.class, "integerCast",
+      Primitive.class, Object.class, RoundingMode.class),
   MEMORY_GET0(MemoryFactory.Memory.class, "get"),
   MEMORY_GET1(MemoryFactory.Memory.class, "get", int.class),
   ENUMERATOR_CURRENT(Enumerator.class, "current"),

core/src/test/java/org/apache/calcite/test/CoreQuidemTest.java

@@ -68,6 +68,15 @@ public static void main(String[] args) throws Exception {
               .with(CalciteConnectionProperty.FUN, SqlLibrary.CALCITE.fun)
               .with(CalciteAssert.Config.SCOTT)
               .connect();
+        case "scott-rounding-half-up":
+          return CalciteAssert.that()
+              .with(CalciteConnectionProperty.PARSER_FACTORY,
+                  ExtensionDdlExecutor.class.getName() + "#PARSER_FACTORY")
+              .with(CalciteConnectionProperty.FUN, SqlLibrary.CALCITE.fun)
+              .with(CalciteConnectionProperty.TYPE_SYSTEM,
+                  CustomRelDataTypeSystem.class.getName() + "#ROUNDING_MODE_HALF_UP")
+              .with(CalciteAssert.Config.SCOTT)
+              .connect();
         case "scott-lenient":
           // Same as "scott", but uses LENIENT conformance.
           // TODO: add a way to change conformance without defining a new

core/src/test/java/org/apache/calcite/test/CustomRelDataTypeSystem.java

@@ -0,0 +1,40 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.calcite.test;
+
+import org.apache.calcite.rel.type.RelDataTypeSystem;
+import org.apache.calcite.rel.type.RelDataTypeSystemImpl;
+
+import java.math.RoundingMode;
+
+/**
+ * Custom type system only for Quidem test.
+ *
+ * <p> Specify the rounding behaviour. In the default implementation,
+ * the rounding mode is {@link RoundingMode#DOWN}, but here is  {@link RoundingMode#HALF_UP}
+ *
+ * <p>The default implementation is {@link #DEFAULT}.
+ */
+
+public class CustomRelDataTypeSystem extends RelDataTypeSystemImpl {
+
+  public static final RelDataTypeSystem ROUNDING_MODE_HALF_UP = new CustomRelDataTypeSystem();
+
+  @Override public RoundingMode roundingMode() {
+    return RoundingMode.HALF_UP;
+  }
+}