content: /*
   * Inkless
   * Copyright (C) 2024 - 2025 Aiven OY
   *
   * This program is free software: you can redistribute it and/or modify
   * it under the terms of the GNU Affero General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU Affero General Public License for more details.
   *
   * You should have received a copy of the GNU Affero General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  package io.aiven.inkless.common.config.validators;
  
  import org.apache.kafka.common.config.ConfigDef;
  
  /**
   * {@link 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();
      }
  }
  