content: /*
   * 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.plan.hep.HepPlanner;
  import org.apache.calcite.plan.hep.HepProgram;
  import org.apache.calcite.plan.hep.HepProgramBuilder;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.logical.LogicalCalc;
  import org.apache.calcite.rel.rules.CoreRules;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rex.RexCall;
  import org.apache.calcite.rex.RexInputRef;
  import org.apache.calcite.rex.RexLocalRef;
  import org.apache.calcite.rex.RexNode;
  import org.apache.calcite.rex.RexShuttle;
  import org.apache.calcite.sql.fun.SqlStdOperatorTable;
  import org.apache.calcite.sql.type.SqlTypeName;
  import org.apache.calcite.tools.RelBuilder;
  
  import org.junit.jupiter.api.Test;
  
  import static org.hamcrest.CoreMatchers.is;
  import static org.hamcrest.MatcherAssert.assertThat;
  
  /**
   * Unit tests for {@link RexShuttle}.
   */
  class RexShuttleTest {
  
    /** Test case for
     * <a href="https://issues.apache.org/jira/browse/CALCITE-3165">[CALCITE-3165]
     * Project#accept(RexShuttle shuttle) does not update rowType</a>. */
    @Test void testProjectUpdatesRowType() {
      final RelBuilder builder = RelBuilder.create(RelBuilderTest.config().build());
  
      // Equivalent SQL: SELECT deptno, sal FROM emp
      final RelNode root =
          builder
              .scan("EMP")
              .project(
                  builder.field("DEPTNO"),
                  builder.field("SAL"))
              .build();
  
      // Equivalent SQL: SELECT CAST(deptno AS VARCHAR), CAST(sal AS VARCHAR) FROM emp
      final RelNode rootWithCast =
          builder
              .scan("EMP")
              .project(
                  builder.cast(builder.field("DEPTNO"), SqlTypeName.VARCHAR),
                  builder.cast(builder.field("SAL"), SqlTypeName.VARCHAR))
              .build();
      final RelDataType type = rootWithCast.getRowType();
  
      // Transform the first expression into the second one, by using a RexShuttle
      // that converts every RexInputRef into a 'CAST(RexInputRef AS VARCHAR)'
      final RelNode rootWithCastViaRexShuttle = root.accept(new RexShuttle() {
        @Override public RexNode visitInputRef(RexInputRef inputRef) {
          return  builder.cast(inputRef, SqlTypeName.VARCHAR);
        }
      });
      final RelDataType type2 = rootWithCastViaRexShuttle.getRowType();
  
      assertThat(type, is(type2));
    }
  
    @Test void testCalcUpdatesRowType() {
      final RelBuilder builder = RelBuilder.create(RelBuilderTest.config().build());
  
      // Equivalent SQL: SELECT deptno, sal, sal + 20 FROM emp
      final RelNode root =
          builder
              .scan("EMP")
              .project(
                  builder.field("DEPTNO"),
                  builder.field("SAL"),
                  builder.call(SqlStdOperatorTable.PLUS,
                      builder.field("SAL"), builder.literal(20)))
              .build();
  
      HepProgram program = new HepProgramBuilder()
          .addRuleInstance(CoreRules.PROJECT_TO_CALC)
          .build();
      HepPlanner planner = new HepPlanner(program);
      planner.setRoot(root);
      LogicalCalc calc = (LogicalCalc) planner.findBestExp();
  
      final RelNode calcWithCastViaRexShuttle = calc.accept(new RexShuttle() {
        @Override public RexNode visitCall(RexCall call) {
          return builder.cast(call, SqlTypeName.VARCHAR);
        }
  
        @Override public RexNode visitLocalRef(RexLocalRef localRef) {
          if (calc.getProgram().getExprList().get(localRef.getIndex())
              instanceof RexCall) {
            return new RexLocalRef(localRef.getIndex(),
                builder.getTypeFactory().createSqlType(SqlTypeName.VARCHAR));
          } else {
            return localRef;
          }
        }
      });
  
      // Equivalent SQL: SELECT deptno, sal, CAST(sal + 20 AS VARCHAR) FROM emp
      final RelNode rootWithCast =
          builder
              .scan("EMP")
              .project(
                  builder.field("DEPTNO"),
                  builder.field("SAL"),
                  builder.cast(
                      builder.call(SqlStdOperatorTable.PLUS,
                          builder.field("SAL"), builder.literal(20)), SqlTypeName.VARCHAR))
              .build();
      assertThat(calcWithCastViaRexShuttle.getRowType(), is(rootWithCast.getRowType()));
    }
  }
  