JPA in a JavaFX Context - jpa

Question

So far I used JPA in a managed container but currently I'm working on a desktop application with JavaFX and JPA and I have to manage the transactions. I have an application that has multiple javafx windows:
First window: It shows some projects in a list (entry)
When you click on an entry it shows some details of that project (details view)
In the details view you can add some information about that project (details form)
First of all I create a project that will be listed in the entry view. Then I enter the details view of that project. In the details view I add a new entry by filling out the third view. I click enter and the details view gets updated with that information. Then I leave the details view and I have a kind of summary in the entry page about the whole project. This all works fine. Then I enter the details view again and edit some stuff in the form (step 3). When I click ok the details view gets updated. Then I leave the details view to return to the entry page but the summary is not updated.
So my problem actually is that the entry page is not updated when the details are updated (the very first time when I create the details the entry page is updated correctly)
Some code...
The entry page [1] opens the details page like this:
protected void showActivities(Project project, Window window) {
try {
FXMLLoader loader = new FXMLLoader(getClass().getResource("ProjectActivities.fxml"));
Stage stage = ModalDialogHelper.createNewModal("Project Activity Log", loader, window);
ProjectActivityController pac = loader.getController();
project = projectDataService.detach(project);
pac.setProject(project);
pac.onPostLoad();
stage.showAndWait();
projectDataService.merge(project);
onReload();
} catch (Exception e) {
e.printStackTrace();
}
}
The details page (ProjectActivities.fxml [2]) opens a the form [3]e in a new window like this (triggered by a button on the window):
#FXML
private void openActivityEditor(ActionEvent event) {
createActivityEditor(((Node) event.getSource()).getScene().getWindow(), null);
}
protected void createActivityEditor(Window window, Activity activity) {
try {
FXMLLoader loader = new FXMLLoader(getClass().getResource("ActivityLogForm.fxml"));
Stage stage = ModalDialogHelper.createNewModal("Create A New Activity...", loader, window);
ActivityLogController controller = loader.getController();
controller.setProject(project);
controller.setActivity((activity != null) ? activityDataService.detach(activity) : activity);
controller.onPostLoad();
stage.showAndWait();
if (activity != null) {
activity = activityDataService.merge(activity);
}
onReload();
} catch (IOException e) {
e.printStackTrace();
}
}
I submit the form [3] (ActivityLogForm.fxml) with this piece of code:
#FXML
private void saveActivity(ActionEvent event) {
if (activity == null) {
activity = new Activity();
activity.setProject(project);
project.getActivities().add(activity);
} else {
activityDataService.merge(activity);
}
activity.setBegin(getBegin());
activity.setStop(getStop());
if (activity.getLog() == null) {
Log log = new Log();
activity.setLog(log);
}
if (details != null) {
activity.getLog().setDetails(details.getText());
}
if (activity.getId() > 0) {
activity = activityDataService.merge(activity);
} else {
activityDataService.persist(activity);
}
activityDataService.detach(activity);
ModalDialogHelper.close(((Node) event.getSource()).getScene().getWindow());
}
Some more infos...
The entry view [1] shows a list of projects inside a VBox. When I click on a project a new window will be opened (details view [2]) and the clicked project will be passed to the details view controller to that view. In the details view one can open a new form (window [3]) to enter the details. By committing the form the details get updated as wanted in the details view [2]. Then I exit the details view and the main view [1] is updated as expected. Then I go back into the details of the very same project and want to change some stuff in the details form [3] (it's the same form as for creating new details as before). I submit the changes and the details view [2] gets updated correctly but then I exit the details view and get back to the main view [1]. But now in this view I don't see the changes I just made but they are written to the datastore.
Update
I forgot to say that i'm using EclipseLink and here's my generic dataservice:
public abstract class AbstractDataService<T> {
protected EntityManager entityManager;
protected int pageSize;
protected Class<T> type;
public AbstractDataService(Class<T> clazz) {
this.type = clazz;
init();
}
protected void init() {
EntityManagerFactory factory = Persistence.createEntityManagerFactory("ttUnit");
entityManager = factory.createEntityManager();
setPageSize(Integer.parseInt(Resources.getString("settings.pagination.default"), 10));
}
public T find(Object o) {
return entityManager.find(type, o);
}
public List<T> findAll() {
CriteriaBuilder builder = entityManager.getCriteriaBuilder();
CriteriaQuery<T> query = builder.createQuery(type);
Root<T> entities = query.from(type);
return entityManager.createQuery(query.select(entities)).getResultList();
}
public List<T> getPage(int page) {
if (isPageOutOfBounds(page)) {
page = correctPage(page);
}
CriteriaBuilder builder = entityManager.getCriteriaBuilder();
CriteriaQuery<T> query = builder.createQuery(type);
Root<T> entities = query.from(type);
return entityManager.createQuery(query.select(entities)).setFirstResult(getFirstResult(page))
.setMaxResults(pageSize).getResultList();
}
private boolean isPageOutOfBounds(int page) {
int pageCount = getPages();
return page < 0 || (pageCount > 0 && page > pageCount);
}
private int correctPage(int page) {
int pageCount = getPages();
if (page < 0) {
page = 1;
}
if (pageCount > 0) {
while (page > pageCount) {
page--;
}
} else {
// reset to the first page
page = 1;
}
return page;
}
public int getPages() {
CriteriaBuilder builder = entityManager.getCriteriaBuilder();
CriteriaQuery<Long> query = builder.createQuery(Long.class);
Expression<Long> entities = builder.count(query.from(type));
long count = entityManager.createQuery(query.select(entities)).getSingleResult();
int pageCount = (int) Math.ceil((double) count / (double) pageSize);
return pageCount;
}
public int getFirstResult(int page) {
return (page - 1) * pageSize;
}
public T merge(T obj) {
try {
entityManager.getTransaction().begin();
return entityManager.merge(obj);
} finally {
entityManager.getTransaction().commit();
}
}
public void persist(T obj) {
try {
entityManager.getTransaction().begin();
entityManager.persist(obj);
} finally {
entityManager.getTransaction().commit();
}
}
public void remove(T obj) {
try {
entityManager.getTransaction().begin();
entityManager.remove(obj);
} finally {
entityManager.getTransaction().commit();
}
}
public void flush() {
try {
entityManager.getTransaction().begin();
entityManager.flush();
} finally {
entityManager.getTransaction().commit();
}
}
public T detach(T obj) {
entityManager.detach(obj);
return obj;
}
public void clear() {
entityManager.clear();
}
/**
* #return the pageSize
*/
public int getPageSize() {
return pageSize;
}
/**
* #param pageSize
* the pageSize to set
*/
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
}
Here's the data model that I'm using:
Project
| 1 (- activities (Cascade: ALL))
|
| 0..n
Activity
- project (Cascade: MERGE, DETACH)

Answer 1

I've found the solution for it. The problem was that when I created a new activity, the activity passed to the ActivityLogController in createActivityEditor was null. Which means that I only merge the entity when it has been edited but I did not merge the project if a new activity is created:
protected void createActivityEditor(Window window, Activity activity) {
try {
FXMLLoader loader = new FXMLLoader(getClass().getResource("ActivityLogForm.fxml"));
Stage stage = ModalDialogHelper.createNewModal("Create A New Activity...", loader, window);
ActivityLogController controller = loader.getController();
controller.setProject(project);
controller.setActivity((activity != null) ? activityDataService.detach(activity) : activity);
controller.onPostLoad();
stage.showAndWait();
if (activity != null) {
// re-attach the existing activity
activity = activityDataService.merge(activity);
} else {
// the activity did not yet exist but the project needs to be
// merged with the new activity
project = projectDataService.merge(project);
}
onReload();
} catch (IOException e) {
e.printStackTrace();
}
}
Like that the project is synchronized with the underlying database and is aware of that new activity. So further changes will be merged because the activity is not null and the project property in the Activity Entity is marked as cascade = MERGE.
Maybe it helps someone with similar issues and thanks for your help