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.fun;
  
  import org.apache.calcite.sql.SqlCall;
  import org.apache.calcite.sql.SqlInternalOperator;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlWriter;
  import org.apache.calcite.sql.type.OperandTypes;
  import org.apache.calcite.sql.type.ReturnTypes;
  import org.apache.calcite.sql.type.SqlTypeName;
  import org.apache.calcite.sql.type.SqlTypeTransforms;
  
  /** Operator that indicates that the result is a json string. */
  class SqlJsonTypeOperator extends SqlInternalOperator {
    SqlJsonTypeOperator() {
      super("JSON_TYPE", SqlKind.JSON_TYPE, MDX_PRECEDENCE, true,
          ReturnTypes.explicit(SqlTypeName.ANY).andThen(SqlTypeTransforms.TO_NULLABLE),
          null, OperandTypes.CHARACTER);
    }
  
    // This is an internal operator, which should not be unparsed to sql.
    @Override public void unparse(SqlWriter writer, SqlCall call, int leftPrec, int rightPrec) {
      call.operand(0).unparse(writer, leftPrec, rightPrec);
    }
  }
  