Skip to content

Database Adapters

A database adapter wraps KacheController's internal read-through / write-through logic and exposes a typed API bound to a specific database client.

Adapter Class Database
MongoDB MongoKacheController MongoDB (via the official Kotlin coroutines driver)
Exposed ExposedKacheController Any Exposed-compatible DB (PostgreSQL, MySQL, H2, SQLite, …)

Constructing an adapter

Both adapters share the same constructor parameters:

MongoKacheController(
    cacheEnabled: () -> Boolean = { true },
    cache: CacheClient,
    asyncWriteScope: CoroutineScope? = null,     // required for setAsync / setAllAsync
    onAsyncWriteError: (Throwable) -> Unit = {},  // optional error handler for write-behind
)

cacheEnabled is evaluated on every call, so you can toggle caching at runtime (e.g. from a feature flag or environment variable) without recreating the controller.

Cache key derivation

Each adapter derives the cache key from its native schema object:

  • MongoDB — "<databaseName>:<collectionName>" from MongoCollection.namespace
  • Exposed — "<schemaName>:<tableName>" from Table.schemaName and Table.tableName (schema prefix omitted when null)

Volatile query results are stored under "<cacheKey>:volatile".