refactor: Use InstantSource as time source

This change updates the modules of OpenDC to always accept
the `InstantSource` interface as source of time. Previously we used
`java.time.Clock`, but this class is bound to a time zone which does not
make sense for our use-cases.

Since `java.time.Clock` implements `java.time.InstantSource`, it can be
used in places that require an `InstantSource` as parameter. Conversion
from `InstantSource` to `Clock` is also possible by invoking
`InstantSource#withZone`.

4 files changed, 12 insertions, 11 deletions

diff --git a/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/FlowEngine.java b/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/FlowEngine.java
index 0ebb0da9..cfa5a48f 100644
--- a/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/FlowEngine.java
+++ b/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/FlowEngine.java
@@ -23,6 +23,7 @@
 package org.opendc.simulator.flow2;
 
 import java.time.Clock;
+import java.time.InstantSource;
 import java.util.ArrayList;
 import java.util.List;
 import kotlin.coroutines.ContinuationInterceptor;
@@ -57,17 +58,17 @@ public final class FlowEngine implements Runnable {
     private boolean active;
 
     private final CoroutineContext coroutineContext;
-    private final Clock clock;
+    private final InstantSource clock;
     private final Delay delay;
 
     /**
-     * Create a new {@link FlowEngine} instance using the specified {@link CoroutineContext} and {@link Clock}.
+     * Create a new {@link FlowEngine} instance using the specified {@link CoroutineContext} and {@link InstantSource}.
      */
-    public static FlowEngine create(CoroutineContext coroutineContext, Clock clock) {
+    public static FlowEngine create(CoroutineContext coroutineContext, InstantSource clock) {
         return new FlowEngine(coroutineContext, clock);
     }
 
-    FlowEngine(CoroutineContext coroutineContext, Clock clock) {
+    FlowEngine(CoroutineContext coroutineContext, InstantSource clock) {
         this.coroutineContext = coroutineContext;
         this.clock = clock;
 
@@ -78,7 +79,7 @@ public final class FlowEngine implements Runnable {
     /**
      * Obtain the (virtual) {@link Clock} driving the simulation.
      */
-    public Clock getClock() {
+    public InstantSource getClock() {
         return clock;
     }
 
diff --git a/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/FlowStage.java b/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/FlowStage.java
index ed5579ea..25f87e04 100644
--- a/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/FlowStage.java
+++ b/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/FlowStage.java
@@ -22,7 +22,7 @@
 
 package org.opendc.simulator.flow2;
 
-import java.time.Clock;
+import java.time.InstantSource;
 import java.util.HashMap;
 import java.util.Map;
 import org.slf4j.Logger;
@@ -67,7 +67,7 @@ public final class FlowStage {
      */
     int timerIndex = -1;
 
-    final Clock clock;
+    final InstantSource clock;
     private final FlowStageLogic logic;
     final FlowGraphInternal parentGraph;
     private final FlowEngine engine;
diff --git a/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/InPort.java b/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/InPort.java
index fba12aaf..16fed4eb 100644
--- a/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/InPort.java
+++ b/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/InPort.java
@@ -22,7 +22,7 @@
 
 package org.opendc.simulator.flow2;
 
-import java.time.Clock;
+import java.time.InstantSource;
 import java.util.Objects;
 
 /**
@@ -40,7 +40,7 @@ public final class InPort implements Inlet {
 
     OutPort output;
     private InHandler handler = InHandlers.noop();
-    private final Clock clock;
+    private final InstantSource clock;
     private final String name;
     private final FlowStage stage;
 
diff --git a/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/OutPort.java b/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/OutPort.java
index 332296a0..1f7ed4ee 100644
--- a/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/OutPort.java
+++ b/opendc-simulator/opendc-simulator-flow/src/main/java/org/opendc/simulator/flow2/OutPort.java
@@ -22,7 +22,7 @@
 
 package org.opendc.simulator.flow2;
 
-import java.time.Clock;
+import java.time.InstantSource;
 import java.util.Objects;
 
 /**
@@ -42,7 +42,7 @@ public final class OutPort implements Outlet {
     private OutHandler handler = OutHandlers.noop();
     private final String name;
     private final FlowStage stage;
-    private final Clock clock;
+    private final InstantSource clock;
 
     OutPort(FlowStage stage, String name, int id) {
         this.name = name;