I am trying to write a function that gets a list of games and use a callback to load the results. This is what i have right now:
public void getAllGames(OrderedRealmCollectionChangeListener<RealmResults<Game>> callback) {
realm.where(Game.class).findAllSortedAsync("startTime").addChangeListener(callback);
}
I want to make decouple Realm(OrderedRealmCollectionChangeListener and RealmResults) from this function, but I don't know how. I tried creating a listener that extends the OrderedRealmCollectionChangeListener but I am still stuck with the RealmResults, and when I try to extend that it said BaseRealm is private so it is impossible for me to create a constructor for that. How can I make it look like this:
public void getAllGames(SomeListener<SomeList<Game>> callback) {
realm.where(Game.class).findAllSortedAsync("startTime").addChangeListener(callback);
}
Derp, all I should have done is write the callback behaviour inside the getAllGames function:
public void getAllGames(SomeListener<List<Game>> callback) {
realm.where(Game.class).findAllSortedAsync("startTime").addChangeListener(new OrderedRealmCollectionChangeListener<RealmResults<Game>>() {
#Override
public void onChange(RealmResults<Game> collection, OrderedCollectionChangeSet changeSet) {
callback.callback(collection);
}
});
}
Related
So I'm learning JavaFX programming and MVC. The control is also its own class and isn't integrated into the view (Which I've heard is one way to go at it). I want it to be separated from the view but because I'm trying to encapsulate everything and leave everything private with limited access to the controls/nodes, I find myself using methods to do almost anything inside of my object almost entirely when using event handlers in the control.
Example (Not an actual program, just wrote it here because I have no short examples.):
View:
public class SamplePane extends BorderPane {
private TextField tfScoreOne;
private Button btnScore, btnPenalty;
private int scoreOne;
public SamplePane() {
// Some constructor
}
public void giveScore() {
scoreOne++;
tfScoreOne.textProperty().setValue("Score: " + Integer.toString(scoreOne);
}
public void takeScore() {
scoreOne--;
tfScoreOne.textProperty().setValue("Score: " + Integer.toString(scoreOne);
}
}
public void btnScoreAddHandler(EventHandler<ActionEvent> handler) {
btnOneAdd.setOnAction(handler);
}
public void btnPenaltyAddHandler(EventHandler<ActionEvent> handler) {
btnOneAdd.setOnAction(handler);
}
Control:
public class SampleController {
public ModuleSelectionController() {
// Some contorller stuff again
samplePaneObj.btnScoreAddHandler(btnScoreHandler);
samplePaneObj.btnPenaltyAddHandler(btnScoreHandler);
}
private class btnScoreHandler implements EventHandler<ActionEvent> {
public void handle(ActionEvent arg0) {
samplePaneObj.giveScore();
}
}
private class btnPenaltyHandler implements EventHandler<ActionEvent> {
public void handle(ActionEvent arg0) {
samplePaneObj.takeScore();
}
}
}
This is mostly pseudocode so forgive me if there are any errors but do you get the point? It seems very arbitrary to just be calling methods but without passing the TextField in the example its hard to not do everything without a method doing all the work.
But is that decoupled enough for MVC? I don't really wanna break encapsulation is the main issue so I can't make the controls public and operate on them directly in the controller.
Is this all just normal? I want to make sure I'm grasping it right.
There is too much that could be said about this here. I'd advise you to have a look at a JavaFX application framework and read its documentation. I learned a lot from it. E.g., have a look here: https://github.com/sialcasa/mvvmFX
Don't make the mistake and try to derive some implementation patterns yourself from all the hello world examples out there on the internet. They all don't teach you how things should be done so that they scale well for real-world projects.
I would like to know
Am I doing things (the following) too complicated?
Is there a better way to update the main content of an activity that allows me to bookmark the event calendar of a store via URL like #MainPlace:eventCalendar?storeId=<id>?
I'm having this ActivityMapper here
public class AppActivityMapper implements ActivityMapper {
private ClientFactory clientFactory;
private MainActivity mainActivity;
// ..
#Override
public Activity getActivity(Place place) {
if (place instanceof LoginPlace) {
return new LoginActivity((LoginPlace) place, clientFactory);
} else if (place instanceof MainPlace) {
if(this.mainActivity == null) {
this.mainActivity = new MainActivity((MainPlace) place, clientFactory);
} else {
this.mainActivity.updateMainContent(((MainPlace) place).getMainContentToken());
}
return this.mainActivity;
}
return null;
}
}
and a MainActivity that controls my MainView that is just a menu ond the left side and the main content on the right side.
I want to decouple my views like in Best Practices for Architecting GWT App which is why I'm trying to control the main content by using events that get fired as something gets clicked in my MenuView.
Therefore I am initializing some event handlers in my MainActivity that react to clicks on the buttons in my menu to delegate the update to the MainView.
public class MainActivity extends AbstractActivity implements MainView.MainPresenter {
#Override
public void start(AcceptsOneWidget panel, EventBus eventBus) {
this.mainView = this.clientFactory.getMainView();
this.mainView.setPresenter(this);
this.mainView.initialize();
this.eventBus = eventBus;
this.eventBus.addHandler(HomeClickedEvent.TYPE, new HomeClickedHandler() {
#Override
public void onHomeClicked(HomeClickedEvent event) {
goTo(new MainPlace("home"));
}
});
this.eventBus.addHandler(EventCalendarClickedEvent.TYPE, new EventCalendarClickedHandler() {
#Override
public void onEventCalendarClicked(EventCalendarClickedEvent eventCalendarClickedEvent) {
goTo(new MainPlace("eventCalendar?storeId=" + eventCalendarClickedEvent.getStoreId()));
}
});
panel.setWidget(this.mainView.asWidget());
}
#Override
public void goTo(Place place) {
this.clientFactory.getPlaceController().goTo(place);
}
#Override
public void updateMainContent(String currentMainContentToken) {
this.mainView.updateMainContent(currentMainContentToken);
}
}
this event gets fired by MenuPresenter.clickedEventCalendar() that reacts to a click on the corresponding menu entry of the MenuView:
public class MenuPresenter implements MenuView.MenuPresenter {
// ..
#Override
public void clickedEventCalendar(Long storeId) {
this.eventBus.fireEvent(new EventCalendarClickedEvent(storeId));
}
}
One of the things I really don't like is this where I append parameters to the token e.g. to display the event calendar of a store given by storeId:
#Override
public void onEventCalendarClicked(EventCalendarClickedEvent eventCalendarClickedEvent) {
goTo(new MainPlace("eventCalendar?storeId=" + eventCalendarClickedEvent.getStoreId()));
}
is there a cleaner solution for a problem like this in GWT? I don't like the fact that I'd have to parse that string in my actual event calendar. Am I using the ActivityMapper wrong or is there simply no other way to do this?
This question should really be split into several separate ones, but that's maybe something to keep in mind for the future. If you're asking one thing then it's easier to answer thoroughly and others can find the answer easier too.
Anyway, I can see a few improvements:
use EventBinder to get rid a bit of the cruft when handling and creating new events.
if you just want to let the presenter know that a button was pressed on in the view (associated with that presenter) sending a custom event over the event bus is a bit of an overkill. Depending on your needs you can expose the button in your view's interface:
public interface Display {
HasClickHandlers getButton();
}
And then just register the ClickHandler in your presenter.
Or, if you need to do something view- and presenter- related on the click, register the ClickHandler in your view and call the presenter:
// In MainView:
#UiHandler("button")
void handleClick(ClickEvent event) {
// Do some stuff with view,
// like hide a panel or change colour
panel.setVisible(false);
// Let the presenter know that a click event has been fired
presenter.onEventCalendarClicked();
}
you're right - creating MainPlace like you are proposing is wrong. You are creating the token too soon - that's what the tokenizer associated with the place is for. You should create MainPlace by passing just the storeId to the constructor - why should MainPresenter (or any other class using this place) should know how to create the token? MainPlace should look more like this:
public class MainPlace extends Place {
private final Long storeId;
public MainPlace(Long storeId) {
this.storeId = storeId;
}
public Long getStoreId() {
return storeId;
}
public static class Tokenizer implements PlaceTokenizer<MainPlace> {
#Override
public MainPlace getPlace(String token) {
return new MainPlace(Long.valueOf(token));
}
#Override
public String getToken(MainPlace place) {
return "eventCalendar?storeId=" + place.getStoreId();
}
}
}
Now, it's the Tokenizer's responisibily to create and parse the token. Just remember to register it on your PlaceHistoryMapper.
After a whole night spent in test (without any luck) I need some support with my interface.
I'm working directly on the Android frameworks and I created a class that works as a Binder with a WeakHashMap to control the callbacks.
Here is the code:
MyCallback:
public interface MyCallback {
public void fire();
}
MyBinder:
public static WeakHashMap<String, MyCallback> mCallbacks =
new WeakHashMap<String, MyCallback>();
public static void setup(MyCallback callback) {
if(mCallbacks.get(callback.getClass().getName()) == null) {
mCallbacks.put(callback.getClass().getName(), callback);
}
}
public static void letsgo() {
Log.d("size", " " + mCallbacks.size()); // IMPORTANT
for (MyCallback cb : mCallbacks.values()) {
cb.fire();
}
}
These 2 classes are written into frameworks so I created 2 test applications with a simple class that implements my interface:
public class FirstApp implements MyCallback {
public FirstApp() {
MyBinder.setup(this);
}
#Override
public void fire() {
Log.d("app1", "fired");
}
}
public class SecondApp implements MyCallback {
public SecondApp() {
MyBinder.setup(this);
}
#Override
public void fire() {
Log.d("app2", "fired");
}
}
Ok at this point I made another class (all these 3 classes, so the 2 that implements the interface and the following one are written into different packages)
In this third class i just call: MyBinder.letsgo();
The issue I'm facing, and that I'm trying to solve since... 8/9 hours is that: If i run letsgo() on the third pack the logs shown 0 for the callbacks WeakHashMap size. if i run letsgo() on the second package it works but it only fires the callback in the same package. the same if i run it on the first package.
I tried also with HashMap instead of WeakHashMap since i red that objects must be referenced but without any luck. I wonder if someone can help me and let me go sleep :D Thanks!
Currently, the below code gives compile erorr, because the listener don't know whats smsTask. I would need a instance of the smsTask in the listener. Is it possible to do this without passing it in the contruntor? It seems redunant if I do:
.createTask(smsTask,new TaskCompleteListener(smsTask){...}
current code:
public void doStuff(){
SmartPhoneTask smsTask=createSmsTask();
super.getSystem().createTask(smsTask,new TaskCompleteListener(){
#Override
public void onTaskComplete() {
releaseResources(smsTask);//error.
}});
}
private SmartPhoneTask createSmsTask() {
return new SmartPhoneTask();
}
createTask:
void createTask(SmartPhoneTask task, TaskCompleteListener listener);
You can declare the variable final :
final SmartPhoneTask smsTask=createSmsTask();
If TaskCompleteListener is under your control you can add a Task parameter to the onTaskComplete() method:
public void onTaskComplete(Task task) {
releaseResources(task);
}
Now the System has to pass the corresponding task to the listener when the onTaskComplete() method is called.
With this way you can also add the same TaskListener to multiple tasks.
I have a simple application and want to make it testable. I m new in this area.
Here is a simple Presenter, taking in mind this code ,could you advice or give me some example how to test it.
public class SomePresenter extends Presenter<MainPanelPresenter.Display>
{
public interface Display extends WidgetDisplay
{
HasClickHandlers getAddButton();
HasClickHandlers getDeleteButton();
void setData(ArrayList<Person> data);
ArrayList<String> getSelectedRows();
Widget asWidget();
}
private final DispatchAsync dispatcher;
public static final Place PLACE = new Place("main");
#Inject
public SomePresenter(DispatchAsync dispatcher, EventBus eventBus, Display display)
{
super(display, eventBus);
this.dispatcher = dispatcher;
bind();
}
protected void onBind()
{
display.getAddButton().addClickHandler(new ClickHandler()
{
public void onClick(ClickEvent event)
{
eventBus.fireEvent(new AddButtonEvent());
}
});
display.getDeleteButton().addClickHandler(new ClickHandler()
{
public void onClick(ClickEvent event)
{
ArrayList<String> list = display.getSelectedRows();
deletePerson(list);
}
});
}
....
private void loadDbData()
{
..........
}
private void deletePerson(ArrayList<String> ids)
{
..........
}
}
Edit:
What does the Presenter is, load initial data from db, have 2 buttons add and delete.
When add is press then a new form is load and user is able to input data and save to the db,
delete button just delete person from db.
Thanks
The general idea of unit testing such a class would be, like for any other class :
create Mock version of the dependencies (Display, EventBus, etc...)
set expectations on what the depdencies should do when the Presenter works
exercice the Presenter and check the expectations
However there are a couple of issues with your version of the Presenter :
The loadDbData() method is not showed, but I assumed it means the Presenter also has access to some other component that does the fetching. Can this component be abtracted in a dependency, and mocked liked the rest ?
Then there is the testing of bind(). The only responsibility of your Presenter in this method is to set up callbacks on some buttons provided by the Display. What you want to test is both :
That the callbacks are set
That the set callbacks do the expected things
A few ideas to help with the later :
You can reduce the coupling between Presenter and Button. If possible, change the Display interface from :
Button getAddButton();
to
addAddButtonClickedHandler(ClickHandler);
This means your Presenter does not have to use a Display object that returns actual BUtton
You can reduce the callbacks content to calling a single method, that you can then test in isolation
protected void bind() {
display.addAddButtonClickHandler(new ClickHandler() {
public void onClick(ClickEvent) {
fireAdded();
}
});
}
// The fireAdded function can be tested independenty of the Display, potentially with
// a mock EventBus
protected void fireAdded() {
event.fireEvent(....)
}
If you really want to check that the callbacks are properly set, than you can use a 'Dummy' implementation of the Display class, that provides you a list of all the callbacks, and let you call them
private class DummyDisplay implements Display {
private List<ClickHandler> addButtonClickHandlers;
public void addAddButtonClickHandler(ClickHandler handler) {
addButtonClickHandlers.add(handler);
}
public void fireAddButtonClick() {
for (ClickHandler h in addButtonClickHandlers) {
h.onClick(new ClickEvent());
}
}
// ....
}
Then your test would :
create a presenter with such a dummy display
use bind to set the callbacks
use display.fireAddButtonClick() to simulate a user clicking
check that has the result of the click, the effects of fireAdded are seen
This type of class (that mostly glue other classes together) can tend to be hard to test ; at some point, it the other classes are thoroughly tested it can become slightly counter productive to concentrate on the gluers, rather than the glued.
Hoping this helps.