The reactor-pool project aims at providing a generic object pool to reactive application that:
- exposes a reactive API (
Publisherinput types,Monoreturn types) - is non-blocking (never blocking a user that makes an attempt to
acquire()a resource) - has lazy acquire behavior
For use-cases where granular control of the release() is needed, the classic path of acquire() is offered, which exposes a PooledRef wrapper to the resource. This also allows access to statistics about the resource lifecycle in the pool.
// given Pool<T> pool Mono<PooledRef<T>> grabResource = pool.acquire(); //no resource is actually requested yet at this point grabResouce.subscribe(); //now one resource is requested from the pool asynchronously //Another example, this time synchronously acquiring, immediately followed up by a release: PooledRef<T> ref = grabResource.block(); //second subscription requests a second resource ref.release().block(); //release() is also asynchronous and lazy
For use-cases where the resource itself can be consumed reactively (exposes a reactive API), a scoped mode of acquisition is offered. withPoolable:
- let the consumer declaratively use the resource
- provides a scope / closure in which the resource is acquired, used as instructed and released automatically
- avoids dealing with an indirection (the resource is directly exposed)
//given at DbConnection type and a Pool<DbConnection> pool pool.withPoolable(resource -> resource //we declare using the connection to create a Statement... .createStatement() //...then performing a SELECT query... .flatMapMany(st -> st.query("SELECT * FROM foo")) //...then marshalling the rows to JSON .map(row -> rowToJson(row)) //(all of which need the live resource) ) //at this point the rest of the steps are outside the scope //so the resource can be released .map(json -> sanitize(json));
Licensed under Apache Software License 2.0