search-repository

Repository Layer

Repository Overview

Repository Locations

Singleton Pattern

Heavy repositories use double-checked locking singletons:

// Location: FileSearchRepository.kt

class FileSearchRepository private constructor(context: Context) {
    
    companion object {
        @Volatile 
        private var INSTANCE: FileSearchRepository? = null
        
        fun getInstance(context: Context): FileSearchRepository =
            INSTANCE ?: synchronized(this) {
                INSTANCE ?: FileSearchRepository(context.applicationContext)
                    .also { INSTANCE = it }
            }
    }
    
    // Repository implementation...
}

// Usage in Activity
val fileSearchRepository = remember { 
    FileSearchRepository.getInstance(applicationContext) 
}

StateFlow Pattern for Reactive Settings

// Location: ProviderSettingsRepository.kt

class ProviderSettingsRepository(context: Context, scope: CoroutineScope) {
    
    // Private mutable state
    private val _webSearchSettings = MutableStateFlow(loadWebSearchSettings())
    
    // Public immutable exposure
    val webSearchSettings: StateFlow<WebSearchSettings> = _webSearchSettings.asStateFlow()
    
    // Update triggers StateFlow emission
    fun updateWebSearchSettings(settings: WebSearchSettings) {
        saveToPrefs(settings)
        _webSearchSettings.value = settings  // UI recomposes automatically
    }
}

// Usage in Composable
@Composable
fun WebSearchSettingsScreen(repository: ProviderSettingsRepository) {
    val settings by repository.webSearchSettings.collectAsState()
    
    // UI automatically updates when settings change
}

Adding a New Repository

1. Create repository class with singleton pattern (if heavy):

   class NewRepository private constructor(context: Context) {
       companion object {
           @Volatile private var INSTANCE: NewRepository? = null
           fun getInstance(context: Context) = INSTANCE ?: synchronized(this) {
               INSTANCE ?: NewRepository(context.applicationContext).also { INSTANCE = it }
           }
       }
   }
   

2. Add StateFlow for reactive data:

   private val _data = MutableStateFlow(loadData())
   val data: StateFlow<DataType> = _data.asStateFlow()
   

3. Use in Activity/Composable:

   val repository = remember { NewRepository.getInstance(context) }
   val data by repository.data.collectAsState()
   

Related Skills

• search-dataflow - How repositories fit into data flow
• search-guides - Adding settings to repositories