Find parent of (multiple) specific children?

Android
1

So I’m working on implementing chat functionality for an app that has the following data object:

class Conversation {

 String objectId;
 List<BackendlessUser> participants;
 List<ChatMessage> messages;
 
 // getters & setters down here
}

Now, I need to Find conversations that have exactly specific participants so I can load the messages from them, but using a where clause like 'participants.objectid = ‘xxxxxxx’ AND participants.objectid = ‘xxxxxxx’ doesn’t seem to work for me. Any idea what I’m doing wrong? Suggestions are appreciated. Thanks.

2

Hello, Omar!

Try to use the following syntax: participants.objectId IN (‘abc’, ‘def’, …)
Hope it helps.
Alex

3

Thanks for the reply Alexandr!

The syntax you suggested seems to return Conversations that include one participant OR others. I need to retrieve Conversations that include both.

For example, let’s say that Bob and John start messaging each other, so I create a Conversation object like so:

Conversation conversation = new Conversation();
conversation.getParticipants().add(/* BackendlessUser bob goes here */);
conversation.getParticipants().add(/* BackendlessUser John goes here */);
 
Backendless.Persistence.of(Conversation.class).save(conversation, .... ); // etc

Later, I want to find the Conversation in which Bob AND John where participants.

4

Ok, I’ve got your case. Unfortunately, there is not direct way to implement it now. As a workaround I can suggest you to implement your case in hosted service.
Anyway, I’ve created an internal ticket for this task. It’s ID is BKNDLSS-12975.
We shall discuss it and inform you about estimations.