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.kafka.connect.util;
  
  import org.apache.kafka.common.config.ConfigDef;
  import org.apache.kafka.common.config.ConfigException;
  import org.apache.kafka.common.utils.Utils;
  
  public class InstantiableClassValidator implements ConfigDef.Validator {
  
      @Override
      public void ensureValid(String name, Object value) {
          if (value == null) {
              // The value will be null if the class couldn't be found; no point in performing follow-up validation
              return;
          }
  
          Class<?> cls = (Class<?>) value;
          try {
              Object o = cls.getDeclaredConstructor().newInstance();
              Utils.maybeCloseQuietly(o, o + " (instantiated for preflight validation");
          } catch (NoSuchMethodException | IllegalAccessException e) {
              throw new ConfigException(name, cls.getName(), "Could not find a public no-argument constructor for class" + (e.getMessage() != null ? ": " + e.getMessage() : ""));
          } catch (ReflectiveOperationException | LinkageError | RuntimeException e) {
              throw new ConfigException(name, cls.getName(), "Could not instantiate class" + (e.getMessage() != null ? ": " + e.getMessage() : ""));
          }
      }
  
      @Override
      public String toString() {
          return "A class with a public, no-argument constructor";
      }
  }
  