Programming Concurrency on the JVM

Typed Actors and Murmurs

The typed actor version of the EnergySource allowed us to invoke methods but ran them as asynchronous messages in sequence under the covers, providing us with thread safety without the need for synchronization. That was easy to create, but our EnergySource is half-baked at this point, missing a key feature—the energy level needs to be replenished automatically.

In the versions we implemented in the previous chapters, the replenish action did not require any user intervention; it was done automatically in the background. As soon as we started the energy source, a timer took care of appropriately increasing the energy level one unit per second.

Implementing that feature in the typed actor version is going to take some ...