Refactoring

- better connection between name of class and logic
- fixed bugs

src/main/java/net/berack/upo/valpre/EndCriteria.java

@@ -7,10 +7,10 @@ public interface EndCriteria {
     /**
      * Determines if the simulation should end based on the statistics of the nodes.
      * 
-     * @param stats The statistics of the nodes in the network.
+     * @param run The current run of the network.
      * @return True if the simulation should end, false otherwise.
      */
-    public boolean shouldEnd(NetStatistics.SingleRun stats);
+    public boolean shouldEnd(NetSimulation.SimulationRun run);
 
     /**
      * Ends the simulation when the given node has reached the specified number of
@@ -33,8 +33,8 @@ public interface EndCriteria {
         }
 
         @Override
-        public boolean shouldEnd(NetStatistics.SingleRun stats) {
+        public boolean shouldEnd(NetSimulation.SimulationRun run) {
-            return stats.nodes.get(nodeName).numArrivals >= this.maxArrivals;
+            return run.getNode(nodeName).stats.numArrivals >= this.maxArrivals;
         }
     }
 
@@ -59,8 +59,8 @@ public interface EndCriteria {
         }
 
         @Override
-        public boolean shouldEnd(NetStatistics.SingleRun stats) {
+        public boolean shouldEnd(NetSimulation.SimulationRun run) {
-            return stats.nodes.get(nodeName).numDepartures >= this.maxDepartures;
+            return run.getNode(nodeName).stats.numDepartures >= this.maxDepartures;
         }
     }
 
@@ -82,8 +82,8 @@ public interface EndCriteria {
         }
 
         @Override
-        public boolean shouldEnd(NetStatistics.SingleRun stats) {
+        public boolean shouldEnd(NetSimulation.SimulationRun run) {
-            return stats.simulationTime >= this.maxTime;
+            return run.getTime() >= this.maxTime;
         }
     }
 }

src/main/java/net/berack/upo/valpre/NetSimulation.java

@@ -1,13 +1,16 @@
 package net.berack.upo.valpre;
 
+import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.PriorityQueue;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
-
+import net.berack.upo.valpre.NetStatistics.RunResult;
-import net.berack.upo.valpre.NetStatistics.SingleRun;
+import net.berack.upo.valpre.NetStatistics.Statistics;
 import net.berack.upo.valpre.rand.Rng;
 import net.berack.upo.valpre.rand.Rngs;
 
@@ -27,19 +30,6 @@ public class NetSimulation {
         this.servers.add(node);
     }
 
-    /**
-     * Runs the simulation with the given seed until a given criteria is met.
-     * 
-     * @param seed      The seed to use for the random number generator.
-     * @param criterias The criteria to determine when to end the simulation. If
-     *                  null then the simulation will run until there are no more
-     *                  events.
-     * @return The statistics the network.
-     */
-    public NetStatistics.SingleRun run(long seed, EndCriteria... criterias) {
-        return this.run(new Rng(seed), criterias);
-    }
-
     /**
      * Run the simualtion multiple times with the given seed and number of runs.
      * The runs are calculated one after the other. For a parallel run see
@@ -54,7 +44,7 @@ public class NetSimulation {
      */
     public NetStatistics run(long seed, int runs, EndCriteria... criterias) {
         var rng = new Rng(seed);
-        var stats = new SingleRun[runs];
+        var stats = new RunResult[runs];
 
         for (int i = 0; i < runs; i++) {
             stats[i] = this.run(rng, criterias);
@@ -65,10 +55,11 @@ public class NetSimulation {
     /**
      * Runs the simulation multiple times with the given seed and number of runs.
      * The runs are calculated in parallel using the given number of threads.
+     * The maximum number of threads are determined by the available processors
+     * and the number of runs.
      * 
      * @param seed      The seed to use for the random number generator.
      * @param runs      The number of runs to perform.
-     * @param numThreads The number of threads to use for the simulation.
      * @param criterias The criteria to determine when to end the simulation. If
      *                  null then the simulation will run until there are no more
      *                  events.
@@ -79,16 +70,15 @@ public class NetSimulation {
     public NetStatistics runParallel(long seed, int runs, EndCriteria... criterias)
             throws InterruptedException, ExecutionException {
         var rngs = new Rngs(seed);
-        var stats = new NetStatistics.SingleRun[runs];
+        var results = new NetStatistics.RunResult[runs];
         var futures = new Future[runs];
 
         var numThreads = Math.min(runs, Runtime.getRuntime().availableProcessors());
-        var threads = Executors.newFixedThreadPool(numThreads);
+        try (var threads = Executors.newFixedThreadPool(numThreads)) {
-
             for (int i = 0; i < runs; i++) {
                 final var id = i;
                 futures[i] = threads.submit(() -> {
-                stats[id] = this.run(rngs.getRng(id), criterias);
+                    results[id] = this.run(rngs.getRng(id), criterias);
                 });
             }
 
@@ -96,8 +86,8 @@ public class NetSimulation {
                 futures[i].get();
             }
 
-        threads.shutdownNow();
+            return new NetStatistics(results);
-        return new NetStatistics(stats);
+        }
     }
 
     /**
@@ -109,22 +99,24 @@ public class NetSimulation {
      *                  events.
      * @return The statistics the network.
      */
-    public NetStatistics.SingleRun run(Rng rng, EndCriteria... criterias) {
+    public NetStatistics.RunResult run(Rng rng, EndCriteria... criterias) {
-        var run = new SimpleRun(this.servers, rng, criterias);
+        var run = new SimulationRun(this.servers, rng, criterias);
-        while (!run.hasEnded()) {
+        while (!run.hasEnded())
             run.processNextEvent();
-        }
         return run.endSimulation();
     }
 
     /**
      * Process an entire run of the simulation.
      */
-    public static class SimpleRun {
+    public static class SimulationRun {
-
+        private final Map<String, NodeBehavior> nodes;
-        private final NetStatistics.SingleRun stats;
         private final PriorityQueue<Event> fel;
         private final EndCriteria[] criterias;
+        private final long timeStartedNano;
+        private final long seed;
+        private final Rng rng;
+        private double time;
 
         /**
          * Creates a new run of the simulation with the given nodes and random number
@@ -132,14 +124,20 @@ public class NetSimulation {
          * 
          * @param nodes     The nodes in the network.
          * @param rng       The random number generator to use.
+         * @param criterias when the simulation has to end.
          */
-        private SimpleRun(Collection<ServerNode> nodes, Rng rng, EndCriteria... criterias) {
+        private SimulationRun(Collection<ServerNode> nodes, Rng rng, EndCriteria... criterias) {
+            this.nodes = new HashMap<>();
             this.fel = new PriorityQueue<>();
-            this.stats = new NetStatistics.SingleRun(nodes, rng);
             this.criterias = criterias;
+            this.timeStartedNano = System.nanoTime();
+            this.seed = rng.getSeed();
+            this.rng = rng;
+            this.time = 0.0d;
 
             // Initial arrivals (if spawned)
             for (var node : nodes) {
+                this.nodes.put(node.name, new NodeBehavior());
                 if (node.shouldSpawnArrival(0))
                     this.addEvent(node, Event.Type.ARRIVAL);
             }
@@ -154,11 +152,27 @@ public class NetSimulation {
          */
         public void processNextEvent() {
             var event = fel.poll();
-            stats.simulationTime = event.time;
+            var node = this.nodes.get(event.node.name);
+            this.time = event.time;
 
             switch (event.type) {
-                case ARRIVAL -> this.processArrival(event);
+                case ARRIVAL -> {
-                case DEPARTURE -> this.processDeparture(event);
+                    if (node.updateArrival(event.time, event.node.maxServers))
+                        this.addEvent(event.node, Event.Type.DEPARTURE);
+
+                    if (event.node.shouldSpawnArrival(node.stats.numArrivals)) {
+                        this.addEvent(event.node, Event.Type.ARRIVAL);
+                    }
+                }
+                case DEPARTURE -> {
+                    if (node.updateDeparture(event.time))
+                        this.addEvent(event.node, Event.Type.DEPARTURE);
+
+                    if (!event.node.shouldSinkDeparture(node.stats.numDepartures)) {
+                        var next = event.node.getChild(this.rng);
+                        this.addEvent(next, Event.Type.ARRIVAL);
+                    }
+                }
             }
         }
 
@@ -167,72 +181,32 @@ public class NetSimulation {
          * 
          * @return The statistics of the network.
          */
-        public NetStatistics.SingleRun endSimulation() {
+        private NetStatistics.RunResult endSimulation() {
-            this.stats.endSimulation();
+            var elapsed = System.nanoTime() - this.timeStartedNano;
-            return this.stats;
+            var nodes = new HashMap<String, Statistics>();
+            for (var entry : this.nodes.entrySet())
+                nodes.put(entry.getKey(), entry.getValue().stats);
+
+            return new RunResult(this.seed, this.time, elapsed, nodes);
         }
 
         /**
-         * Processes an arrival event for the given node at the given time.
+         * Get the current time.
-         * The event is processed by adding the arrival time to the queue, updating the
-         * maximum queue length, and checking if a server is available to process the
-         * arrival. If a server is available, a departure event is created and added to
-         * the future event list.
          * 
-         * @param stats The statistics of the network.
+         * @return a double representing the current time of the simulation.
-         * @param event The arrival event to process.
-         * @param fel   The future event list to add new events to.
          */
-        private void processArrival(Event event) {
+        public double getTime() {
-            var nodeStats = stats.nodes.get(event.node.name);
+            return this.time;
-
-            nodeStats.numArrivals++;
-            nodeStats.enqueue(event.time);
-            if (event.node.maxServers > nodeStats.numServerBusy) {
-                nodeStats.numServerBusy++;
-                this.addEvent(event.node, Event.Type.DEPARTURE);
-            } else {
-                nodeStats.busyTime += stats.simulationTime - nodeStats.lastEventTime;
-            }
-
-            nodeStats.lastEventTime = stats.simulationTime;
-            if (event.node.shouldSpawnArrival(nodeStats.numArrivals)) {
-                this.addEvent(event.node, Event.Type.ARRIVAL);
-            }
         }
 
         /**
-         * Processes a departure event for the given node at the given time.
+         * Get the node requested by the name passed as a string.
-         * The event is processed by removing the departure time from the queue,
-         * updating the busy time, and checking if there are any arrivals in the queue.
-         * If there are, a new departure event is created and added to the fel.
-         * At the end it will add an arrival to the next node if the current node has a
-         * child.
          * 
-         * @param stats The statistics of the network.
+         * @param node the name of the node
-         * @param event The departure event to process.
+         * @return the node
-         * @param fel   The future event list to add new events to.
          */
-        private void processDeparture(Event event) {
+        public NodeBehavior getNode(String node) {
-            var nodeStats = stats.nodes.get(event.node.name);
+            return this.getNode(node);
-            var startService = nodeStats.dequeue();
-            var response = stats.simulationTime - startService;
-
-            if (nodeStats.getQueueSize() < nodeStats.numServerBusy) {
-                nodeStats.numServerBusy--;
-            } else {
-                this.addEvent(event.node, Event.Type.DEPARTURE);
-            }
-
-            nodeStats.numDepartures++;
-            nodeStats.responseTime += response;
-            nodeStats.busyTime += stats.simulationTime - nodeStats.lastEventTime;
-            nodeStats.lastEventTime = stats.simulationTime;
-
-            if (!event.node.shouldSinkDeparture(nodeStats.numDepartures)) {
-                var next = event.node.getChild(stats.rng);
-                this.addEvent(next, Event.Type.ARRIVAL);
-            }
         }
 
         /**
@@ -245,8 +219,8 @@ public class NetSimulation {
          */
         public void addEvent(ServerNode node, Event.Type type) {
             if (node != null) {
-                var delay = node.getPositiveSample(stats.rng);
+                var delay = node.getPositiveSample(this.rng);
-                var event = Event.newType(node, stats.simulationTime + delay, type);
+                var event = Event.newType(node, this.time + delay, type);
                 fel.add(event);
             }
         }
@@ -261,11 +235,68 @@ public class NetSimulation {
                 return true;
             }
             for (var c : this.criterias) {
-                if (c.shouldEnd(stats)) {
+                if (c.shouldEnd(this)) {
                     return true;
                 }
             }
             return false;
         }
     }
+
+    /**
+     * Represents a summary of the behavior of a server node in the network.
+     * It is used by the simulation to track the number of arrivals and departures,
+     * the maximum queue length, the busy time, and the response time.
+     */
+    public static class NodeBehavior {
+        public int numServerBusy = 0;
+        public final Statistics stats = new Statistics();
+        private final ArrayDeque<Double> queue = new ArrayDeque<>();
+
+        /**
+         * TODO
+         * @param time
+         * @param maxServers
+         * @return
+         */
+        public boolean updateArrival(double time, int maxServers) {
+            var total = this.stats.averageQueueLength * this.stats.numArrivals;
+
+            this.queue.add(time);
+            this.stats.numArrivals++;
+            this.stats.averageQueueLength = (total + this.queue.size()) / this.stats.numArrivals;
+            this.stats.maxQueueLength = Math.max(this.stats.maxQueueLength, this.queue.size());
+
+            var startDeparture = maxServers > this.numServerBusy;
+            if (startDeparture) {
+                this.numServerBusy++;
+            } else {
+                this.stats.busyTime += time - this.stats.lastEventTime;
+            }
+
+            this.stats.lastEventTime = time;
+            return startDeparture;
+        }
+
+        /**
+         * TODO
+         * @param time
+         * @return
+         */
+        public boolean updateDeparture(double time) {
+            var startService = this.queue.poll();
+            var response = time - startService;
+
+            var startDeparture = this.queue.size() >= this.numServerBusy;
+            if (!startDeparture) {
+                this.numServerBusy--;
+            }
+
+            this.stats.numDepartures++;
+            this.stats.responseTime += response;
+            this.stats.busyTime += time - this.stats.lastEventTime;
+            this.stats.lastEventTime = time;
+            return startDeparture;
+        }
+    }
 }

src/main/java/net/berack/upo/valpre/NetStatistics.java

@@ -1,16 +1,21 @@
 package net.berack.upo.valpre;
 
-import java.util.ArrayDeque;
-import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 
-import net.berack.upo.valpre.rand.Rng;
+/**
-
+ * TODO
+ */
 public class NetStatistics {
-    public final SingleRun[] runs;
+    public final RunResult[] runs;
+    // public final Run average;
+    // public final Run variance;
 
-    public NetStatistics(SingleRun... runs) {
+    /**
+     * TODO
+     * @param runs
+     */
+    public NetStatistics(RunResult... runs) {
         this.runs = runs;
     }
 
@@ -20,12 +25,11 @@ public class NetStatistics {
      * nodes, including the number of arrivals and departures, the maximum queue
      * length, the busy time, and the response time.
      */
-    public static class SingleRun {
+    public static class RunResult {
-        public final Map<String, Node> nodes;
+        public final Map<String, Statistics> nodes;
         public final long seed;
-        public final Rng rng;
+        public final double simulationTime;
-        public double simulationTime;
+        public final long timeElapsedNano;
-        public long timeElapsedNano;
 
         /**
          * Creates a new statistics object for the given collection of server nodes and
@@ -34,25 +38,11 @@ public class NetStatistics {
          * @param nodes The collection of server nodes to track.
          * @param rng   The random number generator to use.
          */
-        public SingleRun(Collection<ServerNode> nodes, Rng rng) {
+        public RunResult(long seed, double time, long elapsed, HashMap<String, Statistics> nodes) {
-            this.rng = rng;
+            this.seed = seed;
-            this.seed = rng.getSeed();
+            this.simulationTime = time;
-
+            this.timeElapsedNano = elapsed;
-            this.simulationTime = 0.0d;
+            this.nodes = nodes;
-            this.timeElapsedNano = System.nanoTime();
-            this.nodes = new HashMap<String, Node>();
-            for (var node : nodes) {
-                var s = new Node();
-                this.nodes.put(node.name, s);
-            }
-
-        }
-
-        /**
-         * Ends the simulation and calculates the elapsed time.
-         */
-        public void endSimulation() {
-            this.timeElapsedNano = System.nanoTime() - this.timeElapsedNano;
         }
 
         /**
@@ -72,7 +62,7 @@ public class NetStatistics {
             for (var entry : this.nodes.entrySet()) {
                 var stats = entry.getValue();
                 var entrySize = (int) Math.max(size, (int) Math.ceil((Math.log10(stats.numArrivals))));
-                var iFormat = "%" + entrySize + "d";
+                var iFormat = "%" + entrySize + ".0f";
                 var fFormat = "%" + (entrySize + 4) + ".3f";
 
                 System.out.println("===== " + entry.getKey() + " =====");
@@ -87,23 +77,17 @@ public class NetStatistics {
     }
 
     /**
-     * Represents a statistical summary of the behavior of a server node in the
+     * TODO
-     * network.
-     * It is used by the simulation to track the number of arrivals and departures,
-     * the maximum queue length, the busy time, and the response time.
      */
-    public static class Node {
+    public static class Statistics {
-        public int numArrivals = 0;
+        public double numArrivals = 0;
-        public int numDepartures = 0;
+        public double numDepartures = 0;
-        public int maxQueueLength = 0;
+        public double maxQueueLength = 0;
         public double averageQueueLength = 0.0d;
         public double busyTime = 0.0d;
         public double responseTime = 0.0d;
         public double lastEventTime = 0.0d;
 
-        public int numServerBusy = 0;
-        private ArrayDeque<Double> queue = new ArrayDeque<>();
-
         /**
          * Resets the statistics to their initial values.
          */
@@ -111,29 +95,10 @@ public class NetStatistics {
             this.numArrivals = 0;
             this.numDepartures = 0;
             this.maxQueueLength = 0;
-            this.averageQueueLength = 0.0;
+            this.averageQueueLength = 0.0d;
-            this.busyTime = 0.0;
+            this.busyTime = 0.0d;
-            this.responseTime = 0.0;
+            this.responseTime = 0.0d;
-            this.lastEventTime = 0.0;
+            this.lastEventTime = 0.0d;
-            this.numServerBusy = 0;
-            this.queue.clear();
-        }
-
-        public double dequeue() {
-            return this.queue.poll();
-        }
-
-        public void enqueue(double time) {
-            var total = this.averageQueueLength * (this.numArrivals - 1);
-
-            this.queue.add(time);
-            this.averageQueueLength = (total + this.queue.size()) / this.numArrivals;
-            this.maxQueueLength = Math.max(this.maxQueueLength, this.queue.size());
-        }
-
-        public int getQueueSize() {
-            return this.queue.size();
         }
     }
-
 }

src/main/java/net/berack/upo/valpre/ServerNode.java

@@ -125,7 +125,7 @@ public class ServerNode {
      * @param numArrivals The number of arrivals to check against.
      * @return True if the node should spawn an arrival, false otherwise.
      */
-    public boolean shouldSpawnArrival(int numArrivals) {
+    public boolean shouldSpawnArrival(double numArrivals) {
         return this.spawnArrivals > numArrivals;
     }
 
@@ -136,7 +136,7 @@ public class ServerNode {
      * @param numDepartures The number of departures to check against.
      * @return True if the node should sink a departure, false otherwise.
      */
-    public boolean shouldSinkDeparture(int numDepartures) {
+    public boolean shouldSinkDeparture(double numDepartures) {
         return this.sinkDepartures > numDepartures;
     }