content: /*
   * Copyright 2023 Aiven Oy
   *
   * Licensed 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 io.aiven.kafka.tieredstorage.config.validators;
  
  import org.apache.kafka.common.config.ConfigDef;
  
  /**
   * {@link org.apache.kafka.common.config.ConfigDef.Validator} implementation that is used to combine another validator
   * with allowing null as a valid value. Useful for cases like
   * <pre>
   * {@code Null.or(ConfigDef.Range.between(1, Long.MAX_VALUE))}
   * </pre>
   * where existing validator that does not allow null values con be used but null is still a default value.
   */
  public class Null implements ConfigDef.Validator {
  
      private final ConfigDef.Validator validator;
  
      public static ConfigDef.Validator or(final ConfigDef.Validator validator) {
          return new Null(validator);
      }
  
      private Null(final ConfigDef.Validator validator) {
          this.validator = validator;
      }
  
      @Override
      public void ensureValid(final String name, final Object value) {
          if (value != null) {
              validator.ensureValid(name, value);
          }
      }
  
      @Override
      public String toString() {
          return "null or " + validator.toString();
      }
  }
  
  