Add a simple path following goal

src/main/java/net/citizensnpcs/api/ai/goals/FollowPathGoal.java

@@ -0,0 +1,67 @@
+package net.citizensnpcs.api.ai.goals;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.bukkit.Location;
+
+import net.citizensnpcs.api.ai.Goal;
+import net.citizensnpcs.api.ai.tree.Behavior;
+import net.citizensnpcs.api.ai.tree.BehaviorGoalAdapter;
+import net.citizensnpcs.api.ai.tree.BehaviorStatus;
+import net.citizensnpcs.api.npc.NPC;
+
+/**
+ * A sample {@link Goal}/{@link Behavior} that simply moves an {@link NPC} through a list of {@link Location}s.
+ */
+public class FollowPathGoal extends BehaviorGoalAdapter {
+    private int idx;
+    private final NPC npc;
+    private final List<MoveToGoal> path;
+
+    public FollowPathGoal(NPC npc, List<MoveToGoal> path) {
+        this.npc = npc;
+        this.path = path;
+    }
+
+    @Override
+    public void reset() {
+        npc.getNavigator().cancelNavigation();
+        idx = 0;
+    }
+
+    @Override
+    public BehaviorStatus run() {
+        if (idx >= path.size()) {
+            return BehaviorStatus.SUCCESS;
+        }
+        if (!npc.getNavigator().isNavigating()) {
+            setPath();
+        }
+        BehaviorStatus status = path.get(idx).run();
+        if (status == BehaviorStatus.SUCCESS) {
+            idx++;
+            setPath();
+        }
+        return status;
+    }
+
+    private void setPath() {
+        if (idx >= path.size())
+            return;
+        path.get(idx).shouldExecute();
+    }
+
+    @Override
+    public boolean shouldExecute() {
+        return !npc.getNavigator().isNavigating() && path != null;
+    }
+
+    public static FollowPathGoal create(NPC npc, List<MoveToGoal> path) {
+        return new FollowPathGoal(npc, path);
+    }
+
+    public static FollowPathGoal createFromLocations(NPC npc, List<Location> path) {
+        return new FollowPathGoal(npc, path.stream().map(loc -> new MoveToGoal(npc, loc)).collect(Collectors.toList()));
+    }
+}

src/main/java/net/citizensnpcs/api/ai/goals/MoveToGoal.java

@@ -4,7 +4,6 @@
 
 import net.citizensnpcs.api.ai.Goal;
 import net.citizensnpcs.api.ai.event.CancelReason;
-import net.citizensnpcs.api.ai.event.NavigatorCallback;
 import net.citizensnpcs.api.ai.tree.Behavior;
 import net.citizensnpcs.api.ai.tree.BehaviorGoalAdapter;
 import net.citizensnpcs.api.ai.tree.BehaviorStatus;
@@ -44,12 +43,9 @@ public boolean shouldExecute() {
         boolean executing = !npc.getNavigator().isNavigating() && target != null;
         if (executing) {
             npc.getNavigator().setTarget(target);
-            npc.getNavigator().getLocalParameters().addSingleUseCallback(new NavigatorCallback() {
-                @Override
-                public void onCompletion(CancelReason cancelReason) {
-                    finished = true;
-                    reason = cancelReason;
-                }
+            npc.getNavigator().getLocalParameters().addSingleUseCallback(cancelReason -> {
+                finished = true;
+                reason = cancelReason;
             });
         }
         return executing;