MutableProSharedFlow – Enhanced SharedFlow with Initial Value in Kotlin

An open-source Kotlin class that combines the features of MutableSharedFlow and StateFlow

MutableProSharedFlow Kotlin Android Example
Introduction

This is a Kotlin class implementation of [MutableSharedFlow] with an initial value. Shared flows are a type of flow that allows multiple collectors to receive the same stream of data. This implementation is called MutableProSharedFlow and extends the MutableSharedFlow class. It allows the user to set an initial value when creating the flow. Actually this class is mixer of MutableSharedFlow and StateFlow.

Features

Initial Value Support – Provides an initial value to collectors, similar to StateFlow.

Multiple Collectors – Allows multiple collectors to receive the same data stream simultaneously.

Configurable Parameters – Offers customization of replay count, extra buffer capacity, and buffer overflow strategy.

Lightweight and Efficient – Designed for optimal performance with minimal overhead.

How to use
            // Create an instance of MutableProSharedFlow with an initial value
val sharedFlow = MutableProSharedFlow<Int>(initialValue = 0)

// Collector 1
launch {
    sharedFlow.collect { value ->
        println("Collector 1 received: $value")
    }
}

// Collector 2
launch {
    sharedFlow.collect { value ->
        println("Collector 2 received: $value")
    }
}

// Emit new values
sharedFlow.emit(1)
sharedFlow.emit(2)

// In this example, both collectors receive the initial value 0 upon 
// subscription and subsequently receive the emitted values 1 and 2.
Parameters

The class takes in the following parameters:

  • initialValue: the initial value of the flow
  • replay: the number of values that will be buffered and replayed to new collectors when they start collecting
  • extraBufferCapacity: additional buffer capacity for buffering values that can be collected later
  • onBufferOverflow: the strategy to use when the buffer overflows, the default strategy is to suspend

The class has the following functions:

  • collect: accepts a FlowCollector and emits values to it. If the replay cache is empty, the initial value is emitted first.
  • emit: emits a value to the shared flow and updates the initial value
  • resetReplayCache: resets the replay cache to an empty state
  • tryEmit: tries to emit a value to the shared flow without suspending. If it succeeds, it updates the initial value
  • subscriptionCount: returns the number of subscribers to the shared flow
  • replayCache: returns a snapshot of the replay cache The collect, emit, resetReplayCache, and tryEmit functions are overridden from the MutableSharedFlow class. The subscriptionCount and replayCache functions are deprecated in the MutableSharedFlow class and are therefore overridden in this implementation.
Benefits
  • Value will be collect even if new value is same as last value. [Property of SharedFlow]
  • Flow has initial value [Property of StateFlow]. By use of getValue() method.
Crafted In
Repository

https://github.com/thesarangal/MutableProSharedFlow

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