fix error edit task list

refactor: Made Task::id nullable/Optional for semantic reasons

src/main/java/ch/zhaw/gartenverwaltung/TaskFormularController.java

@@ -1,7 +1,6 @@
 package ch.zhaw.gartenverwaltung;
 
 import ch.zhaw.gartenverwaltung.types.Crop;
-import ch.zhaw.gartenverwaltung.types.GrowthPhaseType;
 import ch.zhaw.gartenverwaltung.types.Task;
 import javafx.fxml.FXML;
 import javafx.fxml.Initializable;
@@ -49,8 +48,12 @@ public class TaskFormularController implements Initializable {
         taskName_field.setText(task.getName());
         description_area.setText(task.getDescription());
         start_datePicker.setValue(task.getStartDate());
-        end_datePicker.setValue(task.getEndDate().get());
+        end_datePicker.setValue(task.getEndDate().orElse(null));
+        if(task.getInterval().orElse(null)!=null) {
             interval_field.setText(task.getInterval().get().toString());
+        } else {
+            interval_field.setText(null);
+        }
     }
 
     private Callback<DatePicker, DateCell> getDayCellFactory() {

src/main/java/ch/zhaw/gartenverwaltung/io/JsonTaskList.java

@@ -103,10 +103,9 @@ public class JsonTaskList implements TaskList {
         if(taskMap.isEmpty()) {
             loadTaskListFromFile();
         }
-        if(task.getId() == 0) {
-            task.withId(idProvider.incrementAndGet());
-        }
-        taskMap.put(task.getId(), task);
+        long id = task.getId().orElse(idProvider.incrementAndGet());
+
+        taskMap.put(id, task.withId(id));
         writeTaskListToFile();
     }
 
@@ -122,8 +121,9 @@ public class JsonTaskList implements TaskList {
         if(taskMap.isEmpty()) {
             loadTaskListFromFile();
         }
-        if(taskMap.containsKey(task.getId())){
-            taskMap.remove(task.getId());
+        Long taskId = task.getId().orElseThrow(IOException::new);
+        if(taskMap.containsKey(taskId)){
+            taskMap.remove(taskId);
             writeTaskListToFile();
         }
     }
@@ -163,7 +163,7 @@ public class JsonTaskList implements TaskList {
 
             taskMap = result.stream()
                     .collect(HashMap::new,
-                        (res, task) -> res.put(task.getId(), task),
+                        (res, task) -> res.put(task.getId().orElse(0L), task),
                         (existing, replacement) -> {});
         }
 

src/main/java/ch/zhaw/gartenverwaltung/types/Task.java

@@ -9,7 +9,7 @@ import java.util.Optional;
  * May be created using the builder pattern.
  */
 public class Task {
-    private long id;
+    private Long id;
     private final String name;
     private final String description;
     private final LocalDate startDate;
@@ -62,7 +62,7 @@ public class Task {
     }
 
     // Getters
-    public long getId() { return id; }
+    public Optional<Long> getId() { return Optional.ofNullable(id); }
     public String getName() { return name; }
     public String getDescription() { return description; }
     public LocalDate getStartDate() { return startDate; }

src/main/java/ch/zhaw/gartenverwaltung/types/TaskTemplate.java

@@ -34,6 +34,7 @@ public class TaskTemplate {
     public void setRelativeEndDate(Integer relativeEndDate) {
         this.relativeEndDate = relativeEndDate;
     }
+
     public void setInterval(Integer interval) {
         this.interval = interval;
     }
@@ -45,13 +46,10 @@ public class TaskTemplate {
     }
 
     public Task generateTask(LocalDate realStartDate, long cropId) {
-        Task task = new Task(name, description, realStartDate.plusDays(relativeStartDate), cropId);
-        if (relativeEndDate != null) {
-            task.withEndDate(realStartDate.plusDays(relativeEndDate));
-        }
-        if (interval != null) {
-            task.withInterval(interval);
-        }
-        return task;
+        LocalDate endDate = relativeEndDate != null ? realStartDate.plusDays(relativeEndDate) : null;
+
+        return new Task(name, description, realStartDate.plusDays(relativeStartDate), cropId)
+                .withInterval(interval)
+                .withEndDate(endDate);
     }
 }

src/test/java/ch/zhaw/gartenverwaltung/io/JsonTaskListTest.java

@@ -72,7 +72,8 @@ public class JsonTaskListTest {
     @Test
     @DisplayName("Remove task.")
     void removeTask() {
-        Task task = new Task("Dummy", "Dummy", LocalDate.parse("2022-05-31", formatter), 1).withId(2);
+        Task task = new Task("Dummy", "Dummy", LocalDate.parse("2022-05-31", formatter), 1)
+                .withId(2);
         try {
             testDatabase.removeTask(task);
             List<Task> taskList;

src/test/java/ch/zhaw/gartenverwaltung/models/GardenPlanModelTest.java

@@ -55,8 +55,8 @@ public class GardenPlanModelTest {
                         new GrowthPhase(MonthDay.of(2, 8), MonthDay.of(12, 4), 0, new WateringCycle(0, 0, null), GrowthPhaseType.PLANT, HardinessZone.ZONE_8A, new ArrayList<>()),
                         new GrowthPhase(MonthDay.of(10, 2), MonthDay.of(12, 4), 0, new WateringCycle(0, 0, null), GrowthPhaseType.PLANT, HardinessZone.ZONE_8A, new ArrayList<>())));
 
-        exampleCropOnion = new Crop(examplePlantOnion.id(),  LocalDate.of(2023,3,1));
-        exampleCropOnion.withId(3);
+        exampleCropOnion = new Crop(examplePlantOnion.id(), LocalDate.of(2023, 3, 1))
+                .withId(3);
         examplePlantCarrot = new Plant(
                 1,
                 "Early Carrot",
@@ -67,18 +67,18 @@ public class GardenPlanModelTest {
                 "sandy to loamy, loose soil, free of stones",
                 new ArrayList<>(),
                 List.of(new GrowthPhase(MonthDay.of(4, 4), MonthDay.of(12, 4), 0, new WateringCycle(0, 0, null), GrowthPhaseType.PLANT, HardinessZone.ZONE_8A, new ArrayList<>())));
-        exampleCropCarrot = new Crop(examplePlantCarrot.id(), LocalDate.now());
-        exampleCropCarrot.withId(5);
+        exampleCropCarrot = new Crop(examplePlantCarrot.id(), LocalDate.now())
+                .withId(5);
 
-        exampleCrop1 = new Crop(1, LocalDate.of(2023,2,25));
-        exampleCrop1.withId(0);
-        exampleCrop1.withArea(0.5);
-        exampleCrop2 = new Crop(1,LocalDate.of(2023,3,1));
-        exampleCrop2.withId(1);
-        exampleCrop2.withArea(0.5);
-        exampleCrop3 = new Crop(0,LocalDate.of(2023,3,1));
-        exampleCrop3.withId(2);
-        exampleCrop3.withArea(1.0);
+        exampleCrop1 = new Crop(1, LocalDate.of(2023, 2, 25))
+                .withId(0)
+                .withArea(0.5);
+        exampleCrop2 = new Crop(1, LocalDate.of(2023, 3, 1))
+                .withId(1)
+                .withArea(0.5);
+        exampleCrop3 = new Crop(0, LocalDate.of(2023, 3, 1))
+                .withId(2)
+                .withArea(1.0);
 
         exampleCrops = new ArrayList<>();
         exampleCrops.add(exampleCrop1);