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.sql;
  
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.sql.type.SqlOperandTypeChecker;
  import org.apache.calcite.sql.type.SqlOperandTypeInference;
  import org.apache.calcite.sql.type.SqlReturnTypeInference;
  import org.apache.calcite.sql.type.SqlTypeUtil;
  import org.apache.calcite.sql.validate.SqlValidator;
  import org.apache.calcite.util.Litmus;
  import org.apache.calcite.util.Util;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import static org.apache.calcite.linq4j.Nullness.castNonNull;
  
  /**
   * A postfix unary operator.
   */
  public class SqlPostfixOperator extends SqlOperator {
    //~ Constructors -----------------------------------------------------------
  
    public SqlPostfixOperator(
        String name,
        SqlKind kind,
        int prec,
        @Nullable SqlReturnTypeInference returnTypeInference,
        @Nullable SqlOperandTypeInference operandTypeInference,
        @Nullable SqlOperandTypeChecker operandTypeChecker) {
      super(
          name,
          kind,
          leftPrec(prec, true),
          rightPrec(prec, true),
          returnTypeInference,
          operandTypeInference,
          operandTypeChecker);
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public SqlSyntax getSyntax() {
      return SqlSyntax.POSTFIX;
    }
  
    @Override public @Nullable String getSignatureTemplate(final int operandsCount) {
      Util.discard(operandsCount);
      return "{1} {0}";
    }
  
    @Override protected RelDataType adjustType(
        SqlValidator validator,
        SqlCall call,
        RelDataType type) {
      if (SqlTypeUtil.inCharFamily(type)) {
        // Determine coercibility and resulting collation name of
        // unary operator if needed.
        RelDataType operandType =
            validator.getValidatedNodeType(call.operand(0));
        if (null == operandType) {
          throw new AssertionError("operand's type should have been derived");
        }
        if (SqlTypeUtil.inCharFamily(operandType)) {
          SqlCollation collation = operandType.getCollation();
          assert null != collation
              : "An implicit or explicit collation should have been set";
          type =
              validator.getTypeFactory()
                  .createTypeWithCharsetAndCollation(
                      type,
                      castNonNull(type.getCharset()),
                      collation);
        }
      }
      return type;
    }
  
    @Override public boolean validRexOperands(int count, Litmus litmus) {
      if (count != 1) {
        return litmus.fail("wrong operand count {} for {}", count, this);
      }
      return litmus.succeed();
    }
  }
  