Lunchforce is an employee networking app built on the Salesforce Platform. Using Apex Triggers on CollaborationGroupMember (new as of Spring '13), it matches people in a Chatter Group who have never met before, so they can meet to have lunch and network. Join us to see how you can combine Apex Triggers, Scheduled Apex, and Junction Objects to analyze Chatter connections, adding intelligence to any Chatter Group.

1. Coding Apex Triggers on Chatter
Group Members
A case study in coding for collaboration
Carolyn Grabill
Salesforce.com
Software Development Engineer
@CarolynCodes

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3. Lunchforce Technologies
▪ Using custom junction objects
▪ Triggering on Chatter Group Members
▪ Implementing an interface in Apex
• Schedulable
• Comparable
▪ Posting to Chatter from Apex

4. Lunchforce brings the power
of Chatter to the real world.
Get the source: http://bit.ly/DF13Lunch

5. Lunchforce’s moving parts
User joins Lunchforce
Chatter group
Chatter Group
Member Trigger fires
Luncher__c record is
created for that User
Admin schedules
LunchMatch Apex
Scheduled Apex runs
matching algorithm,
posts results to
Chatter
Users see Chatter
posts, meet up for
lunch together

6. Lunchforce Technologies
▪ Using custom junction objects
▪ Triggering on Chatter Group Members
▪ Implementing an interface in Apex
• Schedulable
• Comparable
▪ Posting to Chatter from Apex

7. Lunchforce’s Custom Objects
Junction Object
Junction Object

8. Records created by matching process
Luncher__c
Location Picker
Luncher__c
Time Picker
Lookup
Lunch_Match__c
Match Record
Lookup

9. Lunchforce Technologies
▪ Using custom junction objects
▪ Triggering on Chatter Group Members
▪ Implementing an interface in Apex
• Schedulable
• Comparable
▪ Posting to Chatter from Apex

10. Chatter Group Member Trigger

11. CollaborationGroupMember fields
▪ CollaborationGroupId
• The Id of the Chatter group joined
▪ CollaborationRole
• Whether the User is Standard or Admin group member
▪ MemberId
• Id of the User joining the group
▪ NotificationFrequency
• Picklist – Daily, Weekly, Never, Post

12. Demo
▪ Example CollaborationGroupMember Trigger
• AddNewLunchers
▪ Trigger in action

13. Lunchforce Technologies
▪ Using custom junction objects
▪ Triggering on Chatter Group Members
▪ Implementing an interface in Apex
• Schedulable
• Comparable
▪ Posting to Chatter from Apex

14. Lunchforce’s moving parts
User joins Lunchforce
Chatter group
Collaboration Group
Member Trigger fires
Luncher__c record is
created for that User
Admin schedules
LunchMatch Apex
Scheduled Apex runs
matching algorithm,
posts results to
Chatter
Users see Chatter
posts, meet up for
lunch together

15. Interfaces
▪ A template that defines methods, but does not implement them
▪ Apex class implements an interface by implementing its methods
▪ Schedulable is an interface built in to Apex
▪ Example:
global class scheduledLunchMatch implements
Schedulable {
global void execute(SchedulableContext ctx) {
goMatchGo();
}
}

17. Demo
▪ Example Schedulable Class
• ScheduledLunchMatch
▪ Scheduling a job in setup

18. Lunchforce Technologies
▪ Using custom junction objects
▪ Triggering on Chatter Group Members
▪ Implementing an interface in Apex
• Schedulable
• Comparable
▪ Posting to Chatter from Apex

19. Problem: how do you maximize
new matches in a group of people,
when some of them have already
met?

20. Solution: sort the lunchers by how
many lunches they’ve already had.

21. Demo
▪ Example Comparable Class
• LuncherWithHistory
▪ Sorting a list of LuncherWithHistory records
• LunchMatcher

22. Lunchforce Technologies
▪ Using custom junction objects
▪ Triggering on Chatter Group Members
▪ Implementing an interface in Apex
• Schedulable
• Comparable
▪ Posting to Chatter from Apex

23. Posting to Chatter from Apex using FeedItem
▪ Represents an entry in the feed, such as changes in a record feed,
including text posts, link posts, and content posts.
▪ Example:
FeedItem fi = new FeedItem();
fi.ParentId = [object id]; //user, account, etc.
fi.Body = “Body of the post”;
insert fi;

24. Demo
▪ Example FeedItem creation
• LuncherWithHistory
▪ Example weekly lunch matchup
▪ Mobile lunch match results

25. Go meet someone new.

26. Carolyn Grabill
Salesforce.com
Software Development Engineer
@CarolynCodes
Get the source: http://bit.ly/DF13Lunch

28. Trigger on CollaborationGroupMember
trigger addNewLunchers on CollaborationGroupMember
(after insert, after delete)
{
if (Trigger.isInsert) {
// When a user joins the group, create a
// Luncher__c record for them
LunchChatter.newLuncherOnGroupJoin(Trigger.new);
} else if (Trigger.isDelete) {
// When a user leaves the group, mark the
// Luncher__c record inactive
LunchChatter.makeLuncherInactiveOnGroupLeave(Trigger.old);
}
}

29. //create a new luncher when someone joins the lunch chatter group
public static void newLuncherOnGroupJoin(List<CollaborationGroupMember> allNewMembers) {
//get the members that joined the lunch match chatter group
List<CollaborationGroupMember> members = new List<CollaborationGroupMember>();
for (CollaborationGroupMember cgm : allNewMembers) {
if (cgm.CollaborationGroupId == LunchChatter.lunchGroupId) {
members.add(cgm);
}
}
if (!members.isEmpty()) {
//for each member, figure out if we need to create a new luncher or update an existing one
for (CollaborationGroupMember cgm : members) {
if (keySet.contains(cgm.MemberId)) {
userIdsForLunchersToActivate.add(cgm.MemberId);
} else {
userIdsForNewLunchers.add(cgm.MemberId);
}
}

30. //create new lunchers and add them to the upsert list
if (!userIdsForNewLunchers.isEmpty()) {
for (User u : [SELECT Id, Name FROM User WHERE Id IN :userIdsForNewLunchers]) {
Luncher__c newLuncher = new Luncher__c(
Name = u.Name,
Status__c = 'Active',
User__c = u.Id);
lunchersToUpsert.add(newLuncher);
}
}
//get existing lunchers to update and add them to the upsert list
if (!userIdsForLunchersToActivate.isEmpty()) {
for (Luncher__c l : [SELECT Id, Status__c, User__c FROM Luncher__c where User__c
IN :userIdsForLunchersToActivate]) {
l.Status__c = 'Active';
lunchersToUpsert.add(l);
}
}
//insert new lunchers, if any were created
if (!lunchersToUpsert.isEmpty()) {
upsert lunchersToUpsert;
}
}
}

31. //mark a luncher inactive when someone leaves the lunch chatter group
public static void makeLuncherInactiveOnGroupLeave(List<CollaborationGroupMember> allDeleted) {
//get the members that are part of the chatter group you actually care about
List<Id> delUserIds = new List<Id>();
for (CollaborationGroupMember cgm : allDeleted) {
if (cgm.CollaborationGroupId == LunchChatter.lunchGroupId) {
delUserIds.add(cgm.MemberId);
}
}
//set status inactive for lunchers with delUserIds
if (!delUserIds.isEmpty()) {
List<Luncher__c> lunchersToUpdate = new List<Luncher__c>();
for (Luncher__c l : [SELECT Id, Status__c, User__c FROM Luncher__c WHERE User__c
IN :delUserIds]) {
l.Status__c = 'Inactive';
lunchersToUpdate.add(l);
}
if (!lunchersToUpdate.isEmpty()) {
update lunchersToUpdate;
}
}
}

32. global class scheduledLunchMatch implements Schedulable {
global void execute(SchedulableContext ctx) {
goMatchGo();
}
//shortcut for demos, to perform a match on command
public void goMatchGo() {
datetime lunchTime = datetime.now();
LunchMatcher lm = new LunchMatcher();
boolean matchSucceeded = lm.performScheduledMatch(lunchTime);
System.assertEquals(true, matchSucceeded);
}
}

33. public boolean performScheduledMatch(DateTime lunchDate) {
//get all the active lunchers
List<Luncher__c> activeLunchers = [SELECT Id, Name from Luncher__c WHERE Status__c = 'Active'];
Map<Id, Luncher__c> luncherMap = new Map<Id, Luncher__c>();
//get all the inactive lunchers
List<Luncher__c> inactiveLunchers = [SELECT Id FROM Luncher__c WHERE Status__c = 'Inactive'];
//get all the previous matches
List<Lunch_Match__c> prevMatches = [SELECT Id, Location_Picker__c, Time_Picker__c from
Lunch_Match__c];
//construct a list of lunchers with history that holds all the previous matches and lunchers
// with no matches
Map<Id, Set<Id>> prevMatchMap = getPrevMatchMap(prevMatches, activeLunchers, inactiveLunchers);
List<LuncherWithHistory> lunchersWithHistory = LuncherWithHistory.convertFromMap(prevMatchMap);
//do the matching
List<Id> thirdWheelIds = new List<Id>(); //holds any unmatched lunchers
List<Lunch_Match__c> newLunchMatches = matchup(lunchersWithHistory, lunchDate, thirdWheelIds);
insert newLunchMatches;
//handle the thirdwheels
handleThirdWheels(thirdWheelids, newLunchMatches);
}

34. /**
* A container class for convenience, representing a single Luncher__c,
* and the set of other Luncher__c's that they have already been matched with,
* based on existing Lunch_Match__c records.
*/
global class LuncherWithHistory implements Comparable {
public Id luncherId;
//id of this luncher
private Set<Id> historySet; //set of ids of other lunchers this luncher has already
//been matched with
//constructor for luncher that does have match history
public LuncherWithHistory(Id luncherId, Set<Id> historySet) {
this.luncherId = luncherId;
this.historySet = historySet;
}
// CompareTo() will return 0 if ids are equal, else, will return 1 if this
// LuncherWithHistory's group size is larger
global Integer compareTo(Object compareTo) {
LuncherWithHistory compareToLuncher = (LuncherWithHistory)compareTo;
if (luncherId == compareToLuncher.luncherId) return 0;
if (historySet.size() > compareToLuncher.historySet.size()) return 1;
return -1;
}
}

35. //given a list of new Lunch Matches, post to each picker's chatter wall
public static void notifyLunchers(List<Lunch_Match__c> matches) {
//construct maps of match to time picker and match to loc picker
for (Lunch_Match__c lm : matches) {
matchToLuncherLoc.put(lm.Id, lm.Location_Picker__c);
matchToLuncherTime.put(lm.Id, lm.Time_Picker__c);
}
//construct a map of luncher id to user id
Map<Id, Luncher__c> luncherIdToLuncherMap = getLunchersFromMatches(matches);
//build the chatter messages
List<FeedItem> feedItems = new List<FeedItem>();
for (Lunch_Match__c match : matches) {
Luncher__c locPicker = luncherIdToLuncherMap.get(matchToLuncherLoc.get(match.Id));
if (locPicker.Receive_Chatter_Notifications__c) {
FeedItem locFeedItem = buildFeedItem(locPicker);
feedItems.add(locFeedItem);
}
//repeat for time picker
}
insert feedItems;
}