cqc
Service代表一个对象的可运行状态和提供的启动和关闭方法。这是一个管理服务生命周期的框架对象
如何使用
Service的生命周期
Service提供的其他方法
- addListener()用于监听服务状态变化
- awaitRunning()阻塞直到服务的状态变为Running
- awaitTerminated()阻塞直到服务的状态变为Terminated或Failed
Guava不建议直接实现Service接口，其提供了其他的一些基类：
- AbstractIdleService
- AbstractExecutionThreadService
- AbstractScheduledService
- AbstractService
ServiceManager
当有多个Service需要统一管理时，可以使用ServiceManager。其提供的方法有：
- startAsync() will start all the services under management. Much like Service#startAsync() you can only call this method once, if all services are NEW.
- stopAsync() will stop all the services under management.
- addListener() will add a ServiceManager.Listener that will be called on major state transitions.
- awaitHealthy() will wait for all services to reach the RUNNING state.
- awaitStopped() will wait for all services to reach a terminal state.
- isHealthy() returns true if all services are RUNNING.
- servicesByState() returns a consistent snapshot of all the services indexed by their state.
- startupTimes() returns a map from Service under management to how long it took for that service to start in milliseconds. The returned map is guaranteed to be ordered by startup time.