com.websudos.phantom.reactivestreams.package.scala Maven / Gradle / Ivy
/*
* Copyright 2013-2015 Websudos, Limited.
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Explicit consent must be obtained from the copyright owner, Outworkers Limited before any redistribution is made.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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package com.websudos.phantom
import akka.actor.ActorSystem
import com.datastax.driver.core.Session
import com.websudos.phantom.batch.BatchType
import com.websudos.phantom.builder.LimitBound
import com.websudos.phantom.builder.query.{ExecutableQuery, RootSelectBlock}
import com.websudos.phantom.connectors.KeySpace
import com.websudos.phantom.dsl.{context => _, _}
import com.websudos.phantom.reactivestreams.iteratee.{Enumerator, Iteratee => PhantomIteratee}
import org.reactivestreams.Publisher
import play.api.libs.iteratee.{Enumeratee, Enumerator => PlayEnumerator}
import play.api.libs.streams.Streams
import scala.concurrent.{ExecutionContext, ExecutionContextExecutor}
import scala.concurrent.duration.FiniteDuration
/**
* Just a wrapper module for enhancing phantom [[CassandraTable]]
* with reactive streams features.
*
* In order to be used, please be sured to import the implicits
* into the scope.
*
* {{{
* import ReactiveCassandra._
* val subscriber = CassandraTableInstance.subscriber()
* }}}
*
* @see [[http://www.reactive-streams.org/]]
* @see [[https://github.com/websudos/phantom]]
*/
package object reactivestreams {
private[this] final val DEFAULT_CONCURRENT_REQUESTS = 5
private[this] final val DEFAULT_BATCH_SIZE = 100
/**
* @tparam CT the concrete type inheriting from [[CassandraTable]]
* @tparam T the type of the streamed element
*/
implicit class StreamedCassandraTable[CT <: CassandraTable[CT, T], T](val ct: CassandraTable[CT, T]) extends AnyVal {
/**
* Gets a reactive streams [[org.reactivestreams.Subscriber]] with
* batching capabilities for some phantom [[CassandraTable]]. This
* subscriber is able to work for both finite short-lived streams
* and never-ending long-lived streams. For the latter, a flushInterval
* parameter can be used.
*
* @param batchSize the number of elements to include in the Cassandra batch
* @param concurrentRequests the number of concurrent batch operations
* @param batchType the type of the batch.
* @see See [[http://docs.datastax.com/en/cql/3.1/cql/cql_reference/batch_r.html]] for further
* explanation.
* @param flushInterval used to schedule periodic batch execution even though the number of statements hasn't
* been reached yet. Useful in never-ending streams that will never been completed.
* @param completionFn a function that will be invoked when the stream is completed
* @param errorFn a function that will be invoked when an error occurs
* @param builder an implicitly resolved [[RequestBuilder]] that wraps a phantom [[com.websudos.phantom.builder.query.ExecutableStatement]].
* Every T element that gets into the stream from the upstream is turned into a ExecutableStatement
* by means of this builder.
* @param system the underlying [[ActorSystem]]. This [[org.reactivestreams.Subscriber]] implementation uses Akka
* actors, but is not restricted to be used in the context of Akka Streams.
* @param session the Cassandra [[com.datastax.driver.core.Session]]
* @param space the Cassandra [[KeySpace]]
* @param ev an evidence to get the T type removed by erasure
* @return the [[org.reactivestreams.Subscriber]] to be connected to a reactive stream typically initiated by
* a [[org.reactivestreams.Publisher]]
*/
def subscriber(
batchSize: Int = DEFAULT_BATCH_SIZE,
concurrentRequests: Int = DEFAULT_CONCURRENT_REQUESTS,
batchType: BatchType = BatchType.Unlogged,
flushInterval: Option[FiniteDuration] = None,
completionFn: () => Unit = () => (),
errorFn: Throwable => Unit = _ => ()
)(implicit
builder: RequestBuilder[CT, T],
system: ActorSystem,
session: Session,
space: KeySpace,
ev: Manifest[T]
): BatchSubscriber[CT, T] = {
new BatchSubscriber[CT, T](
ct.asInstanceOf[CT],
builder,
batchSize,
concurrentRequests,
batchType,
flushInterval,
completionFn,
errorFn
)
}
/**
* Creates a stream publisher based on the default ReactiveStreams implementation.
* This will use the underlying Play enumerator model to convert.
*
* @param session The Cassandra session to execute the enumeration within.
* @param keySpace The target keyspace.
* @return A publisher of records, publishing one record at a time.
*/
def publisher()(
implicit session: Session,
keySpace: KeySpace,
ctx: ExecutionContextExecutor
): Publisher[T] = {
Streams.enumeratorToPublisher(ct.select.all().fetchEnumerator())
}
}
implicit class PublisherConverter[T](val enumerator: PlayEnumerator[T]) extends AnyVal {
def publisher: Publisher[T] = {
Streams.enumeratorToPublisher(enumerator)
}
}
/**
* Returns the product of the arguments,
* throwing an exception if the result overflows a {@code long}.
*
* @param x the first value
* @param y the second value
* @return the result
* @throws ArithmeticException if the result overflows a long
* @since 1.8
*/
def multiplyExact(x: Long, y: Long): Long = {
val r: Long = x * y
val ax: Long = Math.abs(x)
val ay: Long = Math.abs(y)
if (((ax | ay) >> 31) != 0) {
if (((y != 0) && (r / y != x)) || (x == Long.MinValue && y == -1)) {
return Long.MaxValue
}
}
r
}
final val Iteratee = PhantomIteratee
implicit class RootSelectBlockEnumerator[
T <: CassandraTable[T, _],
R
](val block: RootSelectBlock[T, R]) extends AnyVal {
/**
* Produces an Enumerator for [R]ows
* This enumerator can be consumed afterwards with an Iteratee
*
* @param session The Cassandra session in use.
* @param keySpace The keyspace object in use.
* @param ctx The Execution Context.
* @return
*/
def fetchEnumerator()(
implicit session: Session,
keySpace: KeySpace,
ctx: ExecutionContextExecutor
): PlayEnumerator[R] = {
val eventualEnum = block.all().future() map {
resultSet => Enumerator.enumerator(resultSet) through Enumeratee.map(block.fromRow)
}
PlayEnumerator.flatten(eventualEnum)
}
}
// trait ExecutableQuery[T <: CassandraTable[T, _], R, Limit <: LimitBound]
implicit class ExecutableQueryStreamsAugmenter[
T <: CassandraTable[T, _],
R,
Limit <: LimitBound
](val query: ExecutableQuery[T, R, Limit]) extends AnyVal {
/**
* Produces an Enumerator for [R]ows
* This enumerator can be consumed afterwards with an Iteratee
*
* @param session The Cassandra session in use.
* @param keySpace The keyspace object in use.
* @param ctx The Execution Context.
* @return
*/
def fetchEnumerator()(
implicit session: Session,
keySpace: KeySpace,
ctx: ExecutionContextExecutor
): PlayEnumerator[R] = {
val eventualEnum = query.future() map {
resultSet => Enumerator.enumerator(resultSet) through Enumeratee.map(query.fromRow)
}
PlayEnumerator.flatten(eventualEnum)
}
}
}
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