wvlet.airframe.control.Control.scala Maven / Gradle / Ivy
/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package wvlet.airframe.control
import scala.util.control.NonFatal
import scala.concurrent.{ExecutionContext, Future}
import scala.util.{Failure, Success, Try}
/**
*/
object Control {
def withResource[R <: AutoCloseable, U](resource: R)(body: R => U): U = {
try {
body(resource)
} finally {
if (resource != null) {
resource.close()
}
}
}
def withResources[R1 <: AutoCloseable, R2 <: AutoCloseable, U](resource1: R1, resource2: R2)(
body: (R1, R2) => U
): U = {
try {
body(resource1, resource2)
} finally {
closeResources(resource1, resource2)
}
}
/**
* A loan pattern for Future[U].
*
* TODO: Test this after async test is available in 22.5.0
*/
def withResourceAsync[R <: AutoCloseable, U](
resource: R
)(body: R => Future[U])(implicit sc: ExecutionContext): Future[U] = {
Future
.apply(resource)
.flatMap(r => body(r))
.transform { case any =>
closeSafely(any, () => resource.close())
}
}
/**
* Safely close the resource. If the resource is closed successfully, return the preceding result, if closing the
* resource is failed, combine the previous exception (if exists) and the resource closing exception together.
*/
private[control] def closeSafely[U](preceding: Try[U], close: () => Unit): Try[U] = {
Try(close()) match {
case Success(_) =>
preceding
case Failure(e) =>
// If closing the resource failed, report the error in the Future
preceding match {
case Success(x) =>
Failure(e)
case Failure(ex) =>
Failure(MultipleExceptions(List(e, ex)))
}
}
}
def closeResources[R <: AutoCloseable](resources: R*): Unit = {
if (resources != null) {
var exceptionList = List.empty[Throwable]
resources.map { x =>
try {
if (x != null) {
x.close()
}
} catch {
case NonFatal(e) =>
exceptionList = e :: exceptionList
}
}
if (exceptionList.nonEmpty) {
throw MultipleExceptions(exceptionList)
}
}
}
}