带你读《2022技术人的百宝黑皮书》——一个搞定责任链的注解（10）

/**
* 消息限流代理
  */
@Slf4j
public class MessageThrottlerProxy { 
@Autowired
private AcquireThrottlerHandler acquireThrottlerHandler;
private MessageThrottler messageThrottler; 
@PostConstruct
public void init() {
messageThrottler = new MessageThrottlerPipeline()
.addLast(new ClassificationThrottlerHandler())
.addLast(new DuplicateThrottlerHandler())
.addLast(acquireThrottlerHandler); 
}
  /**
  * 限流单个消息
  *
* @param messageThrottlerToken 单个消息令牌
* @return 是否限流成功24  */
public boolean throttle(MessageThrottlerToken messageThrottlerToken) {
if (!SendSwitch.ENABLE_API_THROTTLER) {
return false;
  }
try {
boolean throttled = messageThrottler.throttle(messageThrottlerToken);
return SendSwitch.THROTTLER_ONLY_WATCH ? false : throttled;
} catch (Exception e) {
log.error("Failed to throttle messageSendDTO:" + messageThrottlerToken, e);
// throttle内部异常不应该影响正常请求，遇到此情况直接降级限流通过
return false;
  }
  }
  /**
  * 限流多个消息, 合并策略可通过 {@link SendSwitch#THROTTLER_MERGE_STRATEGY} 开关控制
  *
* @param messageThrottlerTokens 多个消息令牌
* @return 是否限流成功44  */
public boolean throttle(List<MessageThrottlerToken> messageThrottlerTokens) {
if (!SendSwitch.ENABLE_API_THROTTLER) {
return false;
  }
if (CollectionUtils.isEmpty(messageThrottlerTokens)) {
return false;
  }
  MergeStrategy mergeStrategy = MergeStrategy.getByName(SendSwitch.THROT- TLER_MERGE_STRATEGY);
if (mergeStrategy == null) {
log.error("illegal throttler mergeStrategy:" + SendSwitch.THROTTLER_MERGE_STRATEGY);
return false;
  }
try {
boolean throttled = mergeStrategy.throttle(messageThrottler, messageThrottlerTokens);
return SendSwitch.THROTTLER_ONLY_WATCH ? false : throttled;
} catch (Exception e) {
log.error("Failed to throttle messageSendDTO:" + messageThrottlerTokens, e);
// throttle内部异常不应该影响正常请求，遇到此情况直接降级限流通过
return false;
  }
  }
public enum MergeStrategy {
ALL {
@Override
  public boolean throttle(MessageThrottler messageThrottler, List<MessageThrottlerToken> messageThrottlerTokens) {
return messageThrottler.allThrottle(messageThrottlerTokens); 
}
  },
ANY {
@Override
  public boolean throttle(MessageThrottler messageThrottler, List<MessageThrottlerToken> messageThrottlerTokens) {
return messageThrottler.anyThrottle(messageThrottlerTokens);
}
}
public static MergeStrategy getByName(String name) { MergeStrategy[] values = values();
for (MergeStrategy value : values) {
if (value.name().equalsIgnoreCase(name)) { return value;
}
}
return null;
}
public abstract boolean throttle(MessageThrottler messageThrottler, List<MessageThrottlerToken> messageThrottlerTokens);
}
}