yet more wip

agents/src/main/java/uk/ac/ox/poseidon/agents/behaviours/SteppableGridAction.java

@@ -21,13 +21,15 @@
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import lombok.Getter;
+import lombok.ToString;
 import sim.util.Int2D;
 import uk.ac.ox.poseidon.agents.vessels.Vessel;
 
 import java.time.Duration;
 import java.time.LocalDateTime;
 
 @Getter
+@ToString(callSuper = true)
 public abstract class SteppableGridAction extends SteppableAction implements GridAction {
 
     private final Int2D cell;

agents/src/main/java/uk/ac/ox/poseidon/agents/behaviours/destination/ChoosingDestination.java

@@ -20,6 +20,7 @@
 package uk.ac.ox.poseidon.agents.behaviours.destination;
 
 import lombok.RequiredArgsConstructor;
+import lombok.ToString;
 import uk.ac.ox.poseidon.agents.behaviours.Behaviour;
 import uk.ac.ox.poseidon.agents.behaviours.SteppableAction;
 import uk.ac.ox.poseidon.agents.vessels.Vessel;
@@ -47,6 +48,7 @@ public SteppableAction nextAction(
         );
     }
 
+    @ToString(callSuper = true)
     private class Action extends SteppableAction {
 
         private Action(

agents/src/main/java/uk/ac/ox/poseidon/agents/behaviours/strategy/ThereAndBack.java

@@ -26,30 +26,37 @@
 
 import java.time.LocalDateTime;
 
+import static uk.ac.ox.poseidon.agents.behaviours.strategy.ThereAndBack.Status.*;
+
 @RequiredArgsConstructor
 public class ThereAndBack extends BranchingBehaviour {
 
     private final Behaviour fishingDestinationBehaviour;
     private final Behaviour fishingBehaviour;
     private final Behaviour travellingBehaviour;
-
-    private boolean done = false;
+    private Status status = READY;
 
     @Override
     protected Behaviour nextBehaviour(
         final Vessel vessel,
         final LocalDateTime dateTime
     ) {
-        if (done) {
+        if (status == DONE) {
+            status = READY;
             return null;
-        } else if (vessel.isAtPort()) {
+        } else if (status == READY) {
+            status = ACTIVE;
             return fishingDestinationBehaviour;
         } else if (vessel.isAtCurrentDestination()) {
-            done = true;
+            status = DONE;
             return fishingBehaviour;
         } else {
             return travellingBehaviour;
         }
     }
 
+    enum Status {
+        READY, ACTIVE, DONE
+    }
+
 }

agents/src/main/java/uk/ac/ox/poseidon/agents/vessels/Vessel.java

@@ -111,7 +111,8 @@ public Int2D getCurrentCell() {
     }
 
     public boolean isAtCurrentDestination() {
-        return getCurrentCell().equals(getCurrentDestination());
+        final Int2D currentDestination = getCurrentDestination();
+        return currentDestination != null && getCurrentCell().equals(currentDestination);
     }
 
     public boolean isAtPort() {
@@ -139,4 +140,9 @@ public void scheduleNextAction(final TemporalSchedule schedule) {
                 schedule.scheduleOnceIn(action.getDuration(), action);
             });
     }
+
+    @Override
+    public String toString() {
+        return id;
+    }
 }

agents/src/main/java/uk/ac/ox/poseidon/agents/vessels/VesselFactory.java

@@ -28,6 +28,7 @@
 import uk.ac.ox.poseidon.core.Factory;
 import uk.ac.ox.poseidon.core.Simulation;
 import uk.ac.ox.poseidon.core.events.ForwardingEventManager;
+import uk.ac.ox.poseidon.core.schedule.TemporalSchedule;
 import uk.ac.ox.poseidon.core.utils.IdSupplier;
 import uk.ac.ox.poseidon.geography.ports.Port;
 import uk.ac.ox.poseidon.geography.ports.PortGrid;
@@ -58,12 +59,15 @@ public final Vessel get(final Simulation simulation) {
             vesselField,
             new ForwardingEventManager(simulation.getEventManager())
         );
+        final TemporalSchedule temporalSchedule = simulation.getTemporalSchedule();
         vessel.setCurrentCell(
             portGrid.get(simulation).getLocation(vessel.getHomePort()),
-            simulation.getTemporalSchedule().getDateTime()
+            temporalSchedule.getDateTime()
         );
         vessel.pushBehaviour(initialBehaviour.get(simulation, vessel));
-        vessel.scheduleNextAction(simulation.getTemporalSchedule());
+        temporalSchedule.scheduleOnce(__ ->
+            vessel.scheduleNextAction(temporalSchedule)
+        );
         return vessel;
     }
 

core/src/main/java/uk/ac/ox/poseidon/core/suppliers/RandomBooleanSupplier.java

@@ -0,0 +1,37 @@
+/*
+ * POSEIDON: an agent-based model of fisheries
+ * Copyright (c) 2025 CoHESyS Lab [email protected]
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package uk.ac.ox.poseidon.core.suppliers;
+
+import ec.util.MersenneTwisterFast;
+import lombok.RequiredArgsConstructor;
+
+import java.util.function.BooleanSupplier;
+
+@RequiredArgsConstructor
+public class RandomBooleanSupplier implements BooleanSupplier {
+
+    private final double probability;
+    private final MersenneTwisterFast rng;
+
+    @Override
+    public boolean getAsBoolean() {
+        return rng.nextBoolean(probability);
+    }
+}

core/src/main/java/uk/ac/ox/poseidon/core/suppliers/RandomBooleanSupplierFactory.java

@@ -0,0 +1,43 @@
+/*
+ * POSEIDON: an agent-based model of fisheries
+ * Copyright (c) 2025 CoHESyS Lab [email protected]
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package uk.ac.ox.poseidon.core.suppliers;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import uk.ac.ox.poseidon.core.Simulation;
+import uk.ac.ox.poseidon.core.SimulationScopeFactory;
+
+import java.util.function.BooleanSupplier;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class RandomBooleanSupplierFactory extends SimulationScopeFactory<BooleanSupplier> {
+
+    private double probability;
+
+    @Override
+    protected BooleanSupplier newInstance(final Simulation simulation) {
+        return new RandomBooleanSupplier(probability, simulation.random);
+    }
+}

examples/src/main/java/uk/ac/ox/poseidon/examples/BasicScenario.java

@@ -42,8 +42,8 @@
 import uk.ac.ox.poseidon.agents.registers.Register;
 import uk.ac.ox.poseidon.agents.registers.RegisterFactory;
 import uk.ac.ox.poseidon.agents.registers.RegisteringFactory;
+import uk.ac.ox.poseidon.agents.regulations.AlwaysPermittedFactory;
 import uk.ac.ox.poseidon.agents.regulations.FishingLocationCheckerFactory;
-import uk.ac.ox.poseidon.agents.regulations.NeverPermittedFactory;
 import uk.ac.ox.poseidon.agents.tables.FishingActionListenerTableFactory;
 import uk.ac.ox.poseidon.agents.vessels.RandomHomePortFactory;
 import uk.ac.ox.poseidon.agents.vessels.VesselFactory;
@@ -59,6 +59,7 @@
 import uk.ac.ox.poseidon.core.schedule.ScheduledRepeatingFactory;
 import uk.ac.ox.poseidon.core.schedule.SteppableSequenceFactory;
 import uk.ac.ox.poseidon.core.suppliers.PoissonIntSupplierFactory;
+import uk.ac.ox.poseidon.core.suppliers.RandomBooleanSupplierFactory;
 import uk.ac.ox.poseidon.core.suppliers.ShiftedIntSupplierFactory;
 import uk.ac.ox.poseidon.core.time.DateFactory;
 import uk.ac.ox.poseidon.core.time.DateTimeAfterFactory;
@@ -87,7 +88,6 @@
 import java.util.List;
 import java.util.function.Predicate;
 
-import static uk.ac.ox.poseidon.core.suppliers.ConstantBooleanSupplierFactory.ALWAYS_TRUE;
 import static uk.ac.ox.poseidon.core.suppliers.ConstantDurationSuppliers.ONE_DAY_DURATION_SUPPLIER;
 import static uk.ac.ox.poseidon.core.suppliers.ConstantDurationSuppliers.ONE_HOUR_DURATION_SUPPLIER;
 import static uk.ac.ox.poseidon.core.time.PeriodFactory.DAILY;
@@ -154,7 +154,7 @@ public class BasicScenario extends Scenario {
         );
     private VesselScopeFactory<? extends Predicate<Int2D>> fishingLocationChecker =
         new FishingLocationCheckerFactory(
-            new NeverPermittedFactory(),
+            new AlwaysPermittedFactory(),
             pathFinder,
             distance
         );
@@ -237,7 +237,7 @@ public class BasicScenario extends Scenario {
                 new HomeBehaviourFactory(
                     portGrid,
                     hold,
-                    new VesselScopeFactoryDecorator<>(ALWAYS_TRUE),
+                    new VesselScopeFactoryDecorator<>(new RandomBooleanSupplierFactory(0.1)),
                     travellingBehaviour,
                     new LandingBehaviourFactory<>(hold, ONE_HOUR_DURATION_SUPPLIER),
                     new ThereAndBackBehaviourFactory(