Skip to content

# FAQ

## What is the error `Failed to load class "org.slf4j.impl.StaticLoggerBinder"`?

    SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
    SLF4J: Defaulting to no-operation (NOP) logger implementation
    SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

This error is just a warning about the absence of slf4j setup. You may fix this error by following to stackoverflow answer

## How to filter updates in some part of `BehaviourBuilder`?

You may create subcontext with `BehaviourBuilder.``createSubContextAndDoWithUpdatesFilter` and pass there `updatesUpstreamFlow` parameter with any operations over parent behaviour builder:

    buildBehaviourWithLongPolling {
        createSubContextAndDoWithUpdatesFilter(
            updatesUpstreamFlow = filter { /* some condition */ },
            stopOnCompletion = false // disable stopping of sub context after setup
        ) {
            onCommand() //...
        }
    }

### Additional info

- Flows docs
- BehaviourBuilder

### Cases

- Filtering of chats and users:

          updatesUpstreamFlow = filter { it.sourceChat() ?.id == requiredChatId || it.sourceUser() ?.id == requiredUserId }

  - See:
    - Update.sourceChat
    - Update.sourceUser