Question

I have four different processes (diferent methods) that run separately and are scheduled to start in diferent times. This proccesses can also be started manually, and have to run one at the time. Is there any queue implementation that handle this kind of concurrency? Im trying to avoid the same process being in the queue twice, or two proccesses running at the same time.

Answer 1

It seems you’re looking for Executors.newSingleThreadScheduledExecutor():

Creates a single-threaded executor that can schedule commands to run after a given delay, or to execute periodically. (Note however that if this single thread terminates due to a failure during execution prior to shutdown, a new one will take its place if needed to execute subsequent tasks.) Tasks are guaranteed to execute sequentially, and no more than one task will be active at any given time.