Lifecycle / LifecycleManager

Hi everyone! Just going to give a recap on the last backend sharing session.
We are going to move from the previous Startable / Shutdownable system to the new Lifecycle system for classes that need a setup / teardown code when the app starts / shuts down. We are planning to remove Startable and Shutdownable in the future.

Why?

It's hard to order the start / shutdown calls correctly since there might be some dependencies between the started components.
Majority of start()/shutdown() code only passes down the call to the components below it.

What's the replacement?

Lifecycle and LifecycleManager simplifies this. Lifecycle objects registers itself to the LifecycleManager when they are constructed, and LifecycleManager.start() will start all Lifecycle objects when the app is started.

How to use them?

Make your class implement Lifecycle
Add LifecycleManager.registerLifecycle(this) to the end of each constructor
Override the onStart() and onShutdown() methods

How to migrate Startable / Shutdownable components?

Make your class implement Lifecycle
Add LifecycleManager.registerLifecycle(this) to the end of each constructor
Rename the start() method to onStart() and the shutdown() method into onShutdown()
Remove all calls to the old start() and shutdown() methods

For more information about the technical details and reasoning, please refer to the references below.

References

Lifecycle - https://29022131.atlassian.net/wiki/display/BEI/Lifecycle
Migrating from Startable / Shutdownable to Lifecycle -
https://29022131.atlassian.net/wiki/pages/viewpage.action?pageId=191585673 (