[jboss-jira] [JBoss JIRA] (JGRP-1881) TimeService: provide time on request

TimeService: provide time on request ------------------------------------ Key: JGRP-1881 URL: https://issues.jboss.org/browse/JGRP-1881 Project: JGroups Issue Type: Enhancement Reporter: Bela Ban Assignee: Bela Ban Fix For: 3.6 Currently the TimeService registers a task that runs every (say) 500 ms. It gets the current time and updates a field. Threads which get the time from the TimeService get the value of that field, so {{System.currentTimeMillis()}} is not called too much. However, when no thread needs to get the time for a period of time, the TimeService nevertheless calls {{System.currentTimeMillis()}} every 500 ms, and we have an additional task in the timer. h5. SOLUTION * Remove that task which periodically gets the current time * Add a {{timestamp}} field ({{System.nanoTime()}}) which gets set when {{System.currentTimeMillis()}} is called * Add a field {{current_time}} which is set by {{System.currentTimeMillis()}} * When a thread wants to get the current time from the TimeService, it compares the current time with the timestamp and, if 500 ms have elapsed, calls {{System.currentTimeMillis()}}, sets the timestamp and current_time fields and returns the time * If the time elapsed since the last update is less than 500 ms, it returns {{current_time}} There has to be synchronization around getting the current time ({{System.currentTimeMillis()}}), but this could be done with a CAS and a busy loop.