/*
 * Copyright 2021 Apollo 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 com.ctrip.framework.apollo.internals;

import com.ctrip.framework.apollo.enums.ConfigSourceType;
import java.util.Properties;

/**
 * @author Jason Song(song_s@ctrip.com)
 */
public interface ConfigRepository {
  /**
   * Get the config from this repository.
   * @return config
   */
  Properties getConfig();

  /**
   * Set the fallback repo for this repository.
   * @param upstreamConfigRepository the upstream repo
   */
  void setUpstreamRepository(ConfigRepository upstreamConfigRepository);

  /**
   * Add change listener.
   * @param listener the listener to observe the changes
   */
  void addChangeListener(RepositoryChangeListener listener);

  /**
   * Remove change listener.
   * @param listener the listener to remove
   */
  void removeChangeListener(RepositoryChangeListener listener);

  /**
   * Return the config's source type, i.e. where is the config loaded from
   *
   * @return the config's source type
   */
  ConfigSourceType getSourceType();
}
