Hi, instead of subclassing Announcement, i would add the limiting logic to the one receiving the announcements. To keep everything but the view agnostic of this "optimization" detail. Because all you need is to prevent the UI from rendering in intervals less then 100ms. The announcement doesn't care wether the UI should redraw or not.
Fernando On Sun, Jan 20, 2013 at 11:16 AM, Stéphane Ducasse < [email protected]> wrote: > > On Jan 20, 2013, at 10:27 AM, Ben Coman wrote: > > > > > I am considering a use case where a complex UI rendering loop is linked > to an Announcement, which is being fired rapidly (eg < 1ms), and overall > system performance suffers. However the UI rendering loop really only needs > to execute every 100ms since that is sufficient for a user to perceive an > immediate response to their action. So I have rolled-my-own way to achieve > this for which I was looking for some feedback... > > > > 1. Is there any existing feature in Pharo I have missed that can limit > the firing rate of an announcement ? > > not that I know :) > > > 2. Would this be useful to others as a feature to ship with Pharo ? (so > I don't have to roll-my-own, and it gets more experienced eyes to ensure > its right :) ) > > > 3. General comments on my approach, improvements, alternatives. > > > > By way of a use case using Workspace, execute... > > ------------- > > | announcer mainCount uiCount | > > announcer := Announcer new. "RateLimitingAnnouncer new." > > mainCount := uiCount := 0. > > Transcript crShow: 'ui' ; tab; show: 'main' . > > announcer subscribe: AnnouncementMockA do: > > [ uiCount := uiCount + 1. > > "Imagine a longer duration UI rendering loop here" > > Transcript crShow: uiCount asString , ' ' , mainCount asString. > > ]. > > [ 10000 timesRepeat: > > [ mainCount := mainCount + 1. > > "(Delay forMilliseconds: 1 ) wait." > > announcer announce: AnnouncementMockA new. ] > > ] timeToRun . > > ------------- > > With 'Announcer' this takes 10 seconds to execute with the last lines > being... > > 9999 9999 > > 10000 10000 > > > > Replacing 'Announcer' with my own 'RateLimitingAnnouncer' listed below, > this takes 20 milliseconds with the last lines being... > > ui main > > 1 1 > > 2 10000 > > > > Uncommenting the "Delay" takes 30 seconds for Announcer - and 15 seconds > for RateLimitingAnnouncer with last lines of... > > 289 9935 > > 290 10000 > > > > > > Here is my code wrapping #announce: and #initialize... > > ----- > > Announcer subclass: #RateLimitingAnnouncer > > instanceVariableNames: 'maxRateMilliSeconds queuedCounts' > > classVariableNames: '' > > poolDictionaries: '' > > category: 'LEKtrek-Core' > > ----- > > RateLimitingAnnouncer >>initialize > > super initialize . > > maxRateMilliSeconds := 100. > > queuedCounts := Dictionary new. > > ----- > > RateLimitingAnnouncer >>announce: anAnnouncement > > | announcementClass | > > > > "Track how many announcements fired since reset at end of forked Delay" > > announcementClass := anAnnouncement class. > > queuedCounts at: announcementClass > > ifPresent: [ :count | queuedCounts at: announcementClass put: > count + 1 ] > > ifAbsent: [ queuedCounts at: announcementClass put: 1 ]. > > > > "At first announcement since Delay'ed reset, forward this one and set > up Delay to condense subsequent ones. " ( (queuedCounts at: > announcementClass) = 1 ) ifTrue: > > [ [ "fire one announcement only for any announcement > arriving within delay period." > > (Delay forMilliseconds: maxRateMilliSeconds) wait. > [ (queuedCounts at: announcementClass) > 1 ] whileTrue: [ > "At least one announcement arrived before end of Delay. Forward one > announcement only and repeat" queuedCounts at: > announcementClass put: 1. > > super announce: anAnnouncement. > > (Delay forMilliseconds: maxRateMilliSeconds) wait. > ]. > > queuedCounts at: announcementClass put: 0. > > ] fork. ^ super announce: anAnnouncement. ]. > > ----- > > > > cheers -ben > > > > > > >
