merge: Increase minimum Java version to 17 (#115)

This pull request increases the minimum version of Java required by OpenDC to 17.
This new version of Java introduces several new features compared to our old minimum 
version (11), which we attempt to apply in this conversion.

## Implementation Notes :hammer_and_pick:

* Increase minimum Java version to Java 17 
* Use RandomGenerator as randomness source 
* Add common dispatcher interface 
* Add compatibility with Kotlin coroutines
* Use InstantSource as time source
* Re-implement SimulationScheduler as Dispatcher 
* Replace use of CoroutineContext by Dispatcher 

## External Dependencies :four_leaf_clover:

* Java 17

## Breaking API Changes :warning:

* The use of `CoroutineContext` and `Clock` as parameters of classes has been replaced 
  by the `Dispatcher` interface.
* The use of `Clock` has been replaced by `InstantSource` which does not carry time
   zone info.
* The use of `Random` and `SplittableRandom` as parameter type has been replaced 
   by `RandomGenerator`

2 files changed, 10 insertions, 18 deletions

diff --git a/opendc-experiments/opendc-experiments-base/src/main/kotlin/org/opendc/experiments/provisioner/Provisioner.kt b/opendc-experiments/opendc-experiments-base/src/main/kotlin/org/opendc/experiments/provisioner/Provisioner.kt
index 7fe3a2eb..eae5806e 100644
--- a/opendc-experiments/opendc-experiments-base/src/main/kotlin/org/opendc/experiments/provisioner/Provisioner.kt
+++ b/opendc-experiments/opendc-experiments-base/src/main/kotlin/org/opendc/experiments/provisioner/Provisioner.kt
@@ -22,13 +22,12 @@
 
 package org.opendc.experiments.provisioner
 
+import org.opendc.common.Dispatcher
 import org.opendc.experiments.MutableServiceRegistry
 import org.opendc.experiments.ServiceRegistry
 import org.opendc.experiments.internal.ServiceRegistryImpl
-import java.time.Clock
 import java.util.ArrayDeque
 import java.util.SplittableRandom
-import kotlin.coroutines.CoroutineContext
 
 /**
  * A helper class to set up the experimental environment in a reproducible manner.
@@ -37,17 +36,15 @@ import kotlin.coroutines.CoroutineContext
  * [ProvisioningStep]s are executed sequentially and ensure that the necessary infrastructure is configured and teared
  * down after the simulation completes.
  *
- * @param coroutineContext The [CoroutineContext] in which the environment is set up.
- * @param clock The simulation [Clock].
+ * @param dispatcher The [Dispatcher] implementation for scheduling future tasks.
  * @param seed A seed for initializing the randomness of the environment.
  */
-public class Provisioner(coroutineContext: CoroutineContext, clock: Clock, seed: Long) : AutoCloseable {
+public class Provisioner(dispatcher: Dispatcher, seed: Long) : AutoCloseable {
     /**
      * Implementation of [ProvisioningContext].
      */
     private val context = object : ProvisioningContext {
-        override val clock: Clock = clock
-        override val coroutineContext: CoroutineContext = coroutineContext
+        override val dispatcher: Dispatcher = dispatcher
         override val seeder: SplittableRandom = SplittableRandom(seed)
         override val registry: MutableServiceRegistry = ServiceRegistryImpl()
 
diff --git a/opendc-experiments/opendc-experiments-base/src/main/kotlin/org/opendc/experiments/provisioner/ProvisioningContext.kt b/opendc-experiments/opendc-experiments-base/src/main/kotlin/org/opendc/experiments/provisioner/ProvisioningContext.kt
index 73897315..e53044ce 100644
--- a/opendc-experiments/opendc-experiments-base/src/main/kotlin/org/opendc/experiments/provisioner/ProvisioningContext.kt
+++ b/opendc-experiments/opendc-experiments-base/src/main/kotlin/org/opendc/experiments/provisioner/ProvisioningContext.kt
@@ -22,31 +22,26 @@
 
 package org.opendc.experiments.provisioner
 
+import org.opendc.common.Dispatcher
 import org.opendc.experiments.MutableServiceRegistry
-import java.time.Clock
 import java.util.SplittableRandom
-import kotlin.coroutines.CoroutineContext
+import java.util.random.RandomGenerator
 
 /**
  * The [ProvisioningContext] class provides access to shared state between subsequent [ProvisioningStep]s, as well as
- * access to the simulation dispatcher (via [CoroutineContext]), the virtual clock, and a randomness seeder to allow
+ * access to the simulation dispatcher, the virtual clock, and a randomness seeder to allow
  * the provisioning steps to initialize the (simulated) resources.
  */
 public interface ProvisioningContext {
     /**
-     * The [CoroutineContext] in which the provisioner runs.
+     * The [Dispatcher] provided by the provisioner to schedule future events during the simulation.
      */
-    public val coroutineContext: CoroutineContext
-
-    /**
-     * The [Clock] tracking the virtual simulation time.
-     */
-    public val clock: Clock
+    public val dispatcher: Dispatcher
 
     /**
      * A [SplittableRandom] instance used to seed the provisioners.
      */
-    public val seeder: SplittableRandom
+    public val seeder: RandomGenerator
 
     /**
      * A [MutableServiceRegistry] where the provisioned services are registered.