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.runtime.variant;
  
  import org.apache.calcite.runtime.rtti.RuntimeTypeInformation;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /** Base class for the runtime support for values of the VARIANT SQL type. */
  public abstract class VariantValue {
    // We made this an abstract class rather than an interface,
    // because Janino does not like static methods in interfaces.
    public static @Nullable String getTypeString(Object object) {
      if (object instanceof VariantValue) {
        return ((VariantValue) object).getTypeString();
      }
      return null;
    }
  
    /** A string describing the runtime type information of this value. */
    public abstract String getTypeString();
  
    /** Cast this value to the specified type.  Currently, the rule is:
     * if the value has the specified type, the value field is returned, otherwise a SQL
     * NULL is returned. */
    public abstract @Nullable Object cast(RuntimeTypeInformation type);
  
    // Implementation of the array index operator for VARIANT values
    public abstract @Nullable Object item(Object index);
  }
  