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* The use of `CoroutineContext` and `Clock` as parameters of classes has been replaced 
  by the `Dispatcher` interface.
* The use of `Clock` has been replaced by `InstantSource` which does not carry time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* The use of `Random` and `SplittableRandom` as parameter type has been replaced 
   by `RandomGenerator`

3 files changed, 86 insertions, 32 deletions

diff --git a/opendc-common/src/test/kotlin/org/opendc/common/DispatcherCoroutineDispatcherTest.kt b/opendc-common/src/test/kotlin/org/opendc/common/DispatcherCoroutineDispatcherTest.kt
new file mode 100644
index 00000000..af8a7857
--- /dev/null
+++ b/opendc-common/src/test/kotlin/org/opendc/common/DispatcherCoroutineDispatcherTest.kt
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2022 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.common
+
+import kotlinx.coroutines.TimeoutCancellationException
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.withContext
+import kotlinx.coroutines.withTimeout
+import kotlinx.coroutines.yield
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
+import org.opendc.simulator.kotlin.runSimulation
+
+/**
+ * Test suite for [DispatcherCoroutineDispatcher].
+ */
+class DispatcherCoroutineDispatcherTest {
+    @Test
+    fun testYield() = runSimulation {
+        withContext(dispatcher.asCoroutineDispatcher()) {
+            val startTime = dispatcher.currentTime
+            yield()
+            assertEquals(startTime, dispatcher.currentTime)
+        }
+    }
+
+    @Test
+    fun testDelay() = runSimulation {
+        withContext(dispatcher.asCoroutineDispatcher()) {
+            val startTime = dispatcher.currentTime
+            delay(10)
+            assertEquals(startTime + 10, dispatcher.currentTime)
+        }
+    }
+
+    @Test
+    fun testTimeout() = runSimulation {
+        withContext(dispatcher.asCoroutineDispatcher()) {
+            assertThrows<TimeoutCancellationException> {
+                withTimeout(10) {
+                    delay(1000)
+                }
+            }
+
+            assertEquals(10, dispatcher.currentTime)
+        }
+    }
+}
diff --git a/opendc-common/src/test/kotlin/org/opendc/common/util/PacerTest.kt b/opendc-common/src/test/kotlin/org/opendc/common/util/PacerTest.kt
index 3fae2ebc..3235b046 100644
--- a/opendc-common/src/test/kotlin/org/opendc/common/util/PacerTest.kt
+++ b/opendc-common/src/test/kotlin/org/opendc/common/util/PacerTest.kt
@@ -28,26 +28,18 @@ import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertFalse
 import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.assertThrows
 import org.opendc.simulator.kotlin.runSimulation
-import java.time.Clock
-import kotlin.coroutines.EmptyCoroutineContext
 
 /**
  * Test suite for the [Pacer] class.
  */
 class PacerTest {
     @Test
-    fun testEmptyContext() {
-        assertThrows<IllegalArgumentException> { Pacer(EmptyCoroutineContext, Clock.systemUTC(), 100) {} }
-    }
-
-    @Test
     fun testSingleEnqueue() {
         var count = 0
 
         runSimulation {
-            val pacer = Pacer(coroutineContext, clock, quantum = 100) {
+            val pacer = Pacer(dispatcher, /*quantum*/ 100) {
                 count++
             }
 
@@ -62,7 +54,7 @@ class PacerTest {
         var count = 0
 
         runSimulation {
-            val pacer = Pacer(coroutineContext, clock, quantum = 100) {
+            val pacer = Pacer(dispatcher, /*quantum*/ 100) {
                 count++
             }
 
@@ -80,7 +72,7 @@ class PacerTest {
         var count = 0
 
         runSimulation {
-            val pacer = Pacer(coroutineContext, clock, quantum = 100) {
+            val pacer = Pacer(dispatcher, /*quantum*/ 100) {
                 count++
             }
 
@@ -98,7 +90,7 @@ class PacerTest {
         var count = 0
 
         runSimulation {
-            val pacer = Pacer(coroutineContext, clock, quantum = 100) {
+            val pacer = Pacer(dispatcher, /*quantum*/ 100) {
                 count++
             }
 
@@ -116,7 +108,7 @@ class PacerTest {
         var count = 0
 
         runSimulation {
-            val pacer = Pacer(coroutineContext, clock, quantum = 100) {
+            val pacer = Pacer(dispatcher, /*quantum*/ 100) {
                 count++
             }
 
diff --git a/opendc-common/src/test/kotlin/org/opendc/common/util/TimerSchedulerTest.kt b/opendc-common/src/test/kotlin/org/opendc/common/util/TimerSchedulerTest.kt
index 22a26111..3947fa2e 100644
--- a/opendc-common/src/test/kotlin/org/opendc/common/util/TimerSchedulerTest.kt
+++ b/opendc-common/src/test/kotlin/org/opendc/common/util/TimerSchedulerTest.kt
@@ -29,25 +29,18 @@ import org.junit.jupiter.api.Assertions.fail
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.assertThrows
 import org.opendc.simulator.kotlin.runSimulation
-import java.time.Clock
-import kotlin.coroutines.EmptyCoroutineContext
 
 /**
  * A test suite for the [TimerScheduler] class.
  */
-internal class TimerSchedulerTest {
-    @Test
-    fun testEmptyContext() {
-        assertThrows<IllegalArgumentException> { TimerScheduler<Unit>(EmptyCoroutineContext, Clock.systemUTC()) }
-    }
-
+class TimerSchedulerTest {
     @Test
     fun testBasicTimer() {
         runSimulation {
-            val scheduler = TimerScheduler<Int>(coroutineContext, clock)
+            val scheduler = TimerScheduler<Int>(dispatcher)
 
             scheduler.startSingleTimer(0, 1000) {
-                assertEquals(1000, clock.millis())
+                assertEquals(1000, timeSource.millis())
             }
 
             assertTrue(scheduler.isTimerActive(0))
@@ -58,7 +51,7 @@ internal class TimerSchedulerTest {
     @Test
     fun testCancelNonExisting() {
         runSimulation {
-            val scheduler = TimerScheduler<Int>(coroutineContext, clock)
+            val scheduler = TimerScheduler<Int>(dispatcher)
 
             scheduler.cancel(1)
         }
@@ -67,7 +60,7 @@ internal class TimerSchedulerTest {
     @Test
     fun testCancelExisting() {
         runSimulation {
-            val scheduler = TimerScheduler<Int>(coroutineContext, clock)
+            val scheduler = TimerScheduler<Int>(dispatcher)
 
             scheduler.startSingleTimer(0, 1000) {
                 fail()
@@ -76,7 +69,7 @@ internal class TimerSchedulerTest {
             scheduler.startSingleTimer(1, 100) {
                 scheduler.cancel(0)
 
-                assertEquals(100, clock.millis())
+                assertEquals(100, timeSource.millis())
             }
         }
     }
@@ -84,7 +77,7 @@ internal class TimerSchedulerTest {
     @Test
     fun testCancelAll() {
         runSimulation {
-            val scheduler = TimerScheduler<Int>(coroutineContext, clock)
+            val scheduler = TimerScheduler<Int>(dispatcher)
 
             scheduler.startSingleTimer(0, 1000) { fail() }
             scheduler.startSingleTimer(1, 100) { fail() }
@@ -95,12 +88,12 @@ internal class TimerSchedulerTest {
     @Test
     fun testOverride() {
         runSimulation {
-            val scheduler = TimerScheduler<Int>(coroutineContext, clock)
+            val scheduler = TimerScheduler<Int>(dispatcher)
 
             scheduler.startSingleTimer(0, 1000) { fail() }
 
             scheduler.startSingleTimer(0, 200) {
-                assertEquals(200, clock.millis())
+                assertEquals(200, timeSource.millis())
             }
         }
     }
@@ -108,12 +101,12 @@ internal class TimerSchedulerTest {
     @Test
     fun testOverrideBlock() {
         runSimulation {
-            val scheduler = TimerScheduler<Int>(coroutineContext, clock)
+            val scheduler = TimerScheduler<Int>(dispatcher)
 
             scheduler.startSingleTimer(0, 1000) { fail() }
 
             scheduler.startSingleTimer(0, 1000) {
-                assertEquals(1000, clock.millis())
+                assertEquals(1000, timeSource.millis())
             }
         }
     }
@@ -121,7 +114,7 @@ internal class TimerSchedulerTest {
     @Test
     fun testNegativeDelay() {
         runSimulation {
-            val scheduler = TimerScheduler<Int>(coroutineContext, clock)
+            val scheduler = TimerScheduler<Int>(dispatcher)
 
             assertThrows<IllegalArgumentException> {
                 scheduler.startSingleTimer(1, -1) {