content: package com.ctrip.framework.apollo.biz.service;
  
  import com.google.common.base.Strings;
  import com.google.common.collect.Maps;
  
  import com.ctrip.framework.apollo.biz.entity.ServerConfig;
  import com.ctrip.framework.apollo.biz.repository.ServerConfigRepository;
  import com.ctrip.framework.apollo.common.config.RefreshablePropertySource;
  import com.ctrip.framework.apollo.core.ConfigConsts;
  import com.ctrip.framework.foundation.Foundation;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.stereotype.Component;
  
  import java.util.Map;
  import java.util.Objects;
  
  /**
   * @author Jason Song(song_s@ctrip.com)
   */
  @Component
  public class BizDBPropertySource extends RefreshablePropertySource {
  
    private static final Logger logger = LoggerFactory.getLogger(BizDBPropertySource.class);
  
    @Autowired
    private ServerConfigRepository serverConfigRepository;
  
    public BizDBPropertySource(String name, Map<String, Object> source) {
      super(name, source);
    }
  
    public BizDBPropertySource() {
      super("DBConfig", Maps.newConcurrentMap());
    }
  
    String getCurrentDataCenter() {
      return Foundation.server().getDataCenter();
    }
  
    @Override
    protected void refresh() {
      Iterable<ServerConfig> dbConfigs = serverConfigRepository.findAll();
  
      Map<String, Object> newConfigs = Maps.newHashMap();
      //default cluster's configs
      for (ServerConfig config : dbConfigs) {
        if (Objects.equals(ConfigConsts.CLUSTER_NAME_DEFAULT, config.getCluster())) {
          newConfigs.put(config.getKey(), config.getValue());
        }
      }
  
      //data center's configs
      String dataCenter = getCurrentDataCenter();
      for (ServerConfig config : dbConfigs) {
        if (Objects.equals(dataCenter, config.getCluster())) {
          newConfigs.put(config.getKey(), config.getValue());
        }
      }
  
      //cluster's config
      if (!Strings.isNullOrEmpty(System.getProperty(ConfigConsts.APOLLO_CLUSTER_KEY))) {
        String cluster = System.getProperty(ConfigConsts.APOLLO_CLUSTER_KEY);
        for (ServerConfig config : dbConfigs) {
          if (Objects.equals(cluster, config.getCluster())) {
            newConfigs.put(config.getKey(), config.getValue());
          }
        }
      }
  
      //put to environment
      for (Map.Entry<String, Object> config: newConfigs.entrySet()){
        String key = config.getKey();
        Object value = config.getValue();
  
        if (this.source.get(key) == null) {
          logger.info("Load config from DB : {} = {}", key, value);
        } else if (!Objects.equals(this.source.get(key), value)) {
          logger.info("Load config from DB : {} = {}. Old value = {}", key,
                      value, this.source.get(key));
        }
  
        this.source.put(key, value);
  
      }
  
    }
  
  }
  