JarCastingDataCache
An adaptable cache that allows query-like operations.
class Person(val id: Int, val age: Int, val name: String)
/**
* Generates an object that tells caches how to handle this type.
* Here we indicated that instances of MyType should be indexed on their `id` field.
*/
val description = description(Person::id)
val cache = MapDataCache() //A `DataCache` that's backed by a ConcurrentMap. Every `DataCache` can support an arbitrary number of types.
cache.register(description) //Types need to be registered before a cache can use them, this provides an initial setup.
cache.put(Person(500, 24, "Test Dummy"))
val entry = cache.find<Person> { Person::id eq 500 }.single()
cache.find<Person>().update { it.copy(age = it.age + 1) }
cache.find<Person>().remove()
Cascading
DataCache supports cascading of entities linked by properties.
class User(val id: Int, val name: String)
class Message(val id: Int, val userId: Int, val content: String)
val userDescription = description(User::id) {
link(User::id to Message::userId) //will remove messages with the same userId as the removed User's id.
}
val messageDescription = description(Message::id)
val cache = MapDataCache {
forType<Message> { lruHashMap(100) } //only keep the latest 100 messages
}
cache.register(userDescription, messageDescription)
cache.put(User(500, "Test Dummy"))
cache.put(Message(400, 500, "Hello world"))
cache.find<User> { User::id eq 500 }.remove()
val messages = cache.find<Message>().count()
assert(messages == 0)
Annotation processor
DataDescriptions can be automatically generated with the annotation-processor module.
//creates `userDescription` and `messageDescription`
class User(
@Identity
@Link(Message::class, "userId")
val id: Int,
val name: String
)
class Message(
@Identity
val id: Int,
val userId: Int,
val content: String
)
Note that there is currently an issue with kapt relating to repeatable annotations. Because of that entities with multiple @Link annotations on the same property will not generate those links.
