merge: Extract scheduler from simulation coroutine dispatcher (#106)

This pull request extracts the scheduler from the `SimulationCoroutineDispatcher` into 
a separate `SimulationScheduler` class which allows users to re-use the scheduler 
between different coroutine dispatchers.

We implement the `SimulationScheduler` in Java, removing the explicit dependency on 
Kotlin or `kotlinx-coroutines`. The scheduler uses a separate specialized priority queue 
implementation that eliminates allocation in the hot path of the simulator.

## Implementation Notes :hammer_and_pick:

* Add Java-based simulator core
* Use SimulationScheduler in coroutine dispatcher
* Rename runBlockingSimulation to runSimulation

## External Dependencies :four_leaf_clover:

* N/A 

## Breaking API Changes :warning:

* The Kotlin API for simulation has been moved to `org.opendc.simulator.kotlin`.
* `runBlockingSImulation` renamed to `runSimulation`

2 files changed, 11 insertions, 11 deletions

diff --git a/opendc-simulator/opendc-simulator-network/src/test/kotlin/org/opendc/simulator/network/SimNetworkSinkTest.kt b/opendc-simulator/opendc-simulator-network/src/test/kotlin/org/opendc/simulator/network/SimNetworkSinkTest.kt
index 2e6983c8..944c4d6a 100644
--- a/opendc-simulator/opendc-simulator-network/src/test/kotlin/org/opendc/simulator/network/SimNetworkSinkTest.kt
+++ b/opendc-simulator/opendc-simulator-network/src/test/kotlin/org/opendc/simulator/network/SimNetworkSinkTest.kt
@@ -30,16 +30,16 @@ import org.junit.jupiter.api.Assertions.*
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.assertDoesNotThrow
 import org.junit.jupiter.api.assertThrows
-import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.*
 import org.opendc.simulator.flow.source.FixedFlowSource
+import org.opendc.simulator.kotlin.runSimulation
 
 /**
  * Test suite for the [SimNetworkSink] class.
  */
 class SimNetworkSinkTest {
     @Test
-    fun testInitialState() = runBlockingSimulation {
+    fun testInitialState() = runSimulation {
         val engine = FlowEngine(coroutineContext, clock)
         val sink = SimNetworkSink(engine, capacity = 100.0)
 
@@ -49,7 +49,7 @@ class SimNetworkSinkTest {
     }
 
     @Test
-    fun testDisconnectIdempotent() = runBlockingSimulation {
+    fun testDisconnectIdempotent() = runSimulation {
         val engine = FlowEngine(coroutineContext, clock)
         val sink = SimNetworkSink(engine, capacity = 100.0)
 
@@ -58,7 +58,7 @@ class SimNetworkSinkTest {
     }
 
     @Test
-    fun testConnectCircular() = runBlockingSimulation {
+    fun testConnectCircular() = runSimulation {
         val engine = FlowEngine(coroutineContext, clock)
         val sink = SimNetworkSink(engine, capacity = 100.0)
 
@@ -68,7 +68,7 @@ class SimNetworkSinkTest {
     }
 
     @Test
-    fun testConnectAlreadyConnectedTarget() = runBlockingSimulation {
+    fun testConnectAlreadyConnectedTarget() = runSimulation {
         val engine = FlowEngine(coroutineContext, clock)
         val sink = SimNetworkSink(engine, capacity = 100.0)
         val source = mockk<SimNetworkPort>(relaxUnitFun = true)
@@ -80,7 +80,7 @@ class SimNetworkSinkTest {
     }
 
     @Test
-    fun testConnectAlreadyConnected() = runBlockingSimulation {
+    fun testConnectAlreadyConnected() = runSimulation {
         val engine = FlowEngine(coroutineContext, clock)
         val sink = SimNetworkSink(engine, capacity = 100.0)
         val source1 = Source(engine)
@@ -96,7 +96,7 @@ class SimNetworkSinkTest {
     }
 
     @Test
-    fun testConnect() = runBlockingSimulation {
+    fun testConnect() = runSimulation {
         val engine = FlowEngine(coroutineContext, clock)
         val sink = SimNetworkSink(engine, capacity = 100.0)
         val source = spyk(Source(engine))
@@ -112,7 +112,7 @@ class SimNetworkSinkTest {
     }
 
     @Test
-    fun testDisconnect() = runBlockingSimulation {
+    fun testDisconnect() = runSimulation {
         val engine = FlowEngine(coroutineContext, clock)
         val sink = SimNetworkSink(engine, capacity = 100.0)
         val source = spyk(Source(engine))
diff --git a/opendc-simulator/opendc-simulator-network/src/test/kotlin/org/opendc/simulator/network/SimNetworkSwitchVirtualTest.kt b/opendc-simulator/opendc-simulator-network/src/test/kotlin/org/opendc/simulator/network/SimNetworkSwitchVirtualTest.kt
index 62e54ffb..ff6cb66e 100644
--- a/opendc-simulator/opendc-simulator-network/src/test/kotlin/org/opendc/simulator/network/SimNetworkSwitchVirtualTest.kt
+++ b/opendc-simulator/opendc-simulator-network/src/test/kotlin/org/opendc/simulator/network/SimNetworkSwitchVirtualTest.kt
@@ -27,16 +27,16 @@ import io.mockk.verify
 import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.assertThrows
-import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.*
 import org.opendc.simulator.flow.source.FixedFlowSource
+import org.opendc.simulator.kotlin.runSimulation
 
 /**
  * Test suite for the [SimNetworkSwitchVirtual] class.
  */
 class SimNetworkSwitchVirtualTest {
     @Test
-    fun testConnect() = runBlockingSimulation {
+    fun testConnect() = runSimulation {
         val engine = FlowEngine(coroutineContext, clock)
         val sink = SimNetworkSink(engine, capacity = 100.0)
         val source = spyk(Source(engine))
@@ -54,7 +54,7 @@ class SimNetworkSwitchVirtualTest {
     }
 
     @Test
-    fun testConnectClosedPort() = runBlockingSimulation {
+    fun testConnectClosedPort() = runSimulation {
         val engine = FlowEngine(coroutineContext, clock)
         val sink = SimNetworkSink(engine, capacity = 100.0)
         val switch = SimNetworkSwitchVirtual(engine)