A deliberately simple persistent key-value store for Android. It uses SQLite databases to store its data and Kryo binary serialization to (de)serialize objects.
Each entry has a string key and a value object. Typically, values are simple data containers, i.e., POJO or Kotlin data classes. Each May datastore stores its data in a single table inside its corresponding SQLite database. It uses key's hash code as the table primary key to optimise SQLite look-up performance. It uses thread local Kryo instances to (de)serialize values and store them as blobs in the SQLite database.
Grab the latest version from Maven Central at
io.github.ashutoshgngwr:may.
implementation 'io.github.ashutoshgngwr:may:1.0.0'Usually, the clients should not create more than one instance of May per datastore. SQLite can only handle write operations from one thread at a time. Opening multiple May instances on the same datastore may lead to its corruption.
val may = May.openOrCreateDatastore("path/to/my.may.db")
// or May.openOrCreateDatastore(context, "my.may.db", Context.MODE_PRIVATE)
// persist value
may.put("key", "value")
// check if key exists in the store
may.contains("key")
// retrieve value
val value: String? = may.getAs<String>("key")
// remove value
val wasRemoved = may.remove("key")
// list 10 keys by prefix in ascending order skipping the first 5 that match.
val keys = may.keys("prefix/", offset = 5, limit = 10)
// close datastore
may.close()May supports matching keys using a prefix for find-keys, get-all and remove-all operations. These operations use a SQLite index on the key column to optimise lookups.
Under the hood, May uses reentrant read-write locks to synchronize all of its operations, allowing multiple concurrent reads and at most one write at any given instant.
Use
May.enableWriteAheadLogging()
and
May.disableWriteAheadLogging()
to configure WAL on the underlying SQLite database.