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/*
 * Copyright 2014 the original author or authors.
 *
 * 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 net.kuujo.copycat.util;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

/**
 * Base interface for configurable objects.
 *
 * @author Jordan Halterman
 */
public interface Configurable extends Copyable {

  /**
   * Loads a configuration object from the given configuration map.
   *
   * @param config The configuration map from which to load the configuration object.
   * @param  The configuration object type.
   * @return The loaded configuration object.
   * @throws ConfigurationException If the configuration class is missing or invalid
   */
  @SuppressWarnings("unchecked")
  static  T load(Map config) {
    String className = (String) config.get("class");
    if (className == null) {
      throw new ConfigurationException("Cannot load configuration. No configuration class specified");
    }
    try {
      T instance = (T) Class.forName(className).newInstance();
      instance.configure(config);
    } catch (ClassNotFoundException e) {
      throw new ConfigurationException("Invalid configuration class", e);
    } catch (InstantiationException | IllegalAccessException | ClassCastException e) {
      throw new ConfigurationException("Failed to instantiate configuration object", e);
    }

    try {
      Class clazz = Class.forName(className);
      Constructor constructor = clazz.getConstructor(Map.class);
      return (T) constructor.newInstance(config);
    } catch (ClassNotFoundException | NoSuchMethodException e) {
      throw new ConfigurationException("Invalid configuration class", e);
    } catch (InstantiationException | IllegalAccessException | InvocationTargetException | ClassCastException e) {
      throw new ConfigurationException("Failed to instantiate configuration object", e);
    }
  }

  /**
   * Configures the configurable.
   *
   * @param config The configuration.
   */
  void configure(Map config);

  /**
   * Returns the configuration as a map.
   *
   * @return The configuration map.
   */
  Map toMap();

}