com.gwtplatform.mvp.client

Class Presenter<V extends View,Proxy_ extends Proxy<?>>

java.lang.Object

com.gwtplatform.mvp.client.HandlerContainerImpl

com.gwtplatform.mvp.client.PresenterWidget<V>

com.gwtplatform.mvp.client.Presenter<V,Proxy_>

Type Parameters:

V - The View type.

Proxy_ - The Proxy type.

All Implemented Interfaces:

HasHandlers, IsWidget, HandlerContainer, HasPopupSlot, HasSlots

Direct Known Subclasses:

TabContainerPresenter

public abstract class Presenter<V extends View,Proxy_ extends Proxy<?>>
extends PresenterWidget<V>

A singleton presenter, the basic building block of the model-view-presenter architecture. Each logical page of your application will usually correspond to a singleton Presenter. If you need to separate logic from view in a simple graphical component, you might consider using a PresenterWidget.

For more details on the hierarchical organization of presenters, see PresenterWidget.

Each presenter is associated to a Proxy which is responsible for listening to the various events of interest for this presenter. This makes it possible to lazily instantiate the presenter and use GWT code splitting. Proxies are automatically generated for you based on the information contained in the presenter. For this purpose, your presenter has to define an embedded interface extending Proxy or ProxyPlace. Then you should apply various annotations to that interface in order to specify the characteristics of your presenter. For example, the following code indicates that the presenter will use GWT code splitting and will be reachable at url http://mydomain.com#main:

 public class MainPagePresenter extends
     Presenter<MainPagePresenter.MyView, MainPagePresenter.MyProxy> {

   public interface MyView extends View {}

  @ProxyCodeSplit
  @NameToken("main")
   public interface MyProxy extends ProxyPlace<MainPagePresenter> {}

  @Inject
   public MainPagePresenter(EventBus eventBus, MyView view, MyProxy proxy) {
     super(eventBus, view, proxy, Presenter.RevealType.Root);
   }
 }
 

One of ProxyStandard, ProxyCodeSplit or ProxyCodeSplitBundle must always annotate the Proxy interface.

To reveal a presenter associated to a ProxyPlace you can simply navigate to an hyperlink corresponding to this place's name token. The PlaceManager offers a number of method for building such hyperlinks. If you want to reveal it programatically, you should build a PlaceRequest and call one of the following method:

• PlaceManager.revealPlace(PlaceRequest)
• PlaceManager.revealRelativePlace(PlaceRequest)
• PlaceManager.revealRelativePlace(PlaceRequest, int)

If the presenter is associated to a regular Proxy and does not have a name token then you should call the forceReveal() method. For such presenters, it is customary to define an event responsible of revealing them in order to enforce loose coupling. This event is then handled by the presenter using the ProxyEvent mechanism.

If the presenter is revealed and is not currently visible, then its revealInParent() method will be called.

To hide a presenter, you can reveal another one in the same slot or you can use one of the methods described in PresenterWidget.

A presenter has a number of lifecycle methods that you can hook on to:

• HandlerContainerImpl.onBind()
• PresenterWidget.onReveal()
• PresenterWidget.onReset()
• PresenterWidget.onHide()
• HandlerContainerImpl.onUnbind()

Revealing or hiding a PresenterWidget triggers an internal chain of events that result in these lifecycle methods being called. For an example, here is what happens when a presenter is revealed (either via forceReveal(), or through a PlaceManager method):

• The presenter's revealInParent() is call and it asks to be set in one of its parent slot by firing a RevealContentEvent
• If a presenter already occupies this slot it is removed.
• If the presenter owning the slot is currently visible then PresenterWidget.onHide() is called on the removed presenter and, recursively, on its children (bottom-up: first the children, then the parent)
• If the parent is not visible, it asks to be set in one of its parent slot by firing a RevealContentEvent too, this continues recursively until a visible presenter is reached, or until a presenter fires RevealRootContentEvent or RevealRootLayoutContentEvent
• When the above chain stops, PresenterWidget.onReveal() is called on all the presenters that were traversed. (top down: first the parent, then the children);
• Finally PresenterWidget.onReset() is called on all the currently visible presenters (top-down: first the parent, then the children).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Presenter.RevealType The RevealType define which event will be fired in the default revealInParent().

Constructor Summary

Constructors

Constructor and Description
Presenter(boolean autoBind, EventBus eventBus, V view, Proxy_ proxy) Creates a Presenter that is not necessarily using automatic binding.
Presenter(EventBus eventBus, V view, Proxy_ proxy) Creates a Presenter that uses automatic binding.
Presenter(EventBus eventBus, V view, Proxy_ proxy, GwtEvent.Type<RevealContentHandler<?>> slot) Creates a Presenter that uses automatic binding.
Presenter(EventBus eventBus, V view, Proxy_ proxy, Presenter.RevealType revealType) Creates a Presenter that uses automatic binding.
Presenter(EventBus eventBus, V view, Proxy_ proxy, Presenter.RevealType revealType, GwtEvent.Type<RevealContentHandler<?>> slot) Creates a Presenter that uses automatic binding.

Method Summary

Methods

Modifier and Type	Method and Description
void	bind() Call this method after the object is constructed in order to bind all its handlers.
void	forceReveal() Reveals the presenter, bypassing any service offered by the PlaceManager.
Proxy_	getProxy() Returns the Proxy attached to this presenter.
protected Presenter.RevealType	getRevealType() Returns the Presenter.RevealType of this presenter.
protected GwtEvent.Type<RevealContentHandler<?>>	getSlot() Returns the slot where this presenter is to be revealed.
void	prepareFromRequest(PlaceRequest request) Prepare the state of the presenter given the information contained in the PlaceRequest.
protected void	revealInParent() Requests that the presenter reveal itself in its parent presenter.
protected void	setRevealType(Presenter.RevealType revealType) Set the Presenter.RevealType of this presenter.
protected void	setSlot(GwtEvent.Type<RevealContentHandler<?>> slot) Set the slot where this presenter is to be revealed.
void	unbind() Call this method when you want to release the object and its handlers are not needed anymore.
boolean	useManualReveal() Verifies if this presenter can be revealed automatically or if it is meant to be revealed manually.

Methods inherited from class com.gwtplatform.mvp.client.PresenterWidget

addHandler, addRegisteredHandler, addToPopupSlot, addToPopupSlot, addToSlot, addVisibleHandler, asWidget, clearSlot, fireEvent, getEventBus, getView, getWidget, isVisible, onHide, onReset, onReveal, removeFromPopupSlot, removeFromSlot, setInSlot, setInSlot

Methods inherited from class com.gwtplatform.mvp.client.HandlerContainerImpl

isBound, onBind, onUnbind, registerHandler

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Presenter

public Presenter(boolean autoBind,
         EventBus eventBus,
         V view,
         Proxy_ proxy)

Creates a Presenter that is not necessarily using automatic binding. Automatic binding will only work when instantiating this object using Guice/GIN dependency injection. See HandlerContainerImpl.HandlerContainerImpl(boolean) for more details on automatic binding.

Parameters:

autoBind - true to request automatic binding, false otherwise.

eventBus - The EventBus.

view - The View.

proxy - The Proxy.

Presenter

public Presenter(EventBus eventBus,
         V view,
         Proxy_ proxy)

Creates a Presenter that uses automatic binding. This will only work when instantiating this object using Guice/GIN dependency injection. See HandlerContainerImpl.HandlerContainerImpl() for more details on automatic binding.

Parameters:

eventBus - The EventBus.

view - The View.

proxy - The Proxy.

Presenter

public Presenter(EventBus eventBus,
         V view,
         Proxy_ proxy,
         Presenter.RevealType revealType)

Creates a Presenter that uses automatic binding. This will only work when instantiating this object using Guice/GIN dependency injection. See HandlerContainerImpl.HandlerContainerImpl() for more details on automatic binding.

Parameters:

eventBus - The EventBus.

view - The View.

proxy - The Proxy.

revealType - The Presenter.RevealType.

Presenter

public Presenter(EventBus eventBus,
         V view,
         Proxy_ proxy,
         GwtEvent.Type<RevealContentHandler<?>> slot)

Creates a Presenter that uses automatic binding. This will only work when instantiating this object using Guice/GIN dependency injection. See HandlerContainerImpl.HandlerContainerImpl() for more details on automatic binding.

Parameters:

eventBus - The EventBus.

view - The View.

proxy - The Proxy.

slot - The slot where to reveal this presenter see GwtEvent.Type and RevealContentHandler.

Presenter

public Presenter(EventBus eventBus,
         V view,
         Proxy_ proxy,
         Presenter.RevealType revealType,
         GwtEvent.Type<RevealContentHandler<?>> slot)

Creates a Presenter that uses automatic binding. This will only work when instantiating this object using Guice/GIN dependency injection. See HandlerContainerImpl.HandlerContainerImpl() for more details on automatic binding.

Parameters:

eventBus - The EventBus.

view - The View.

proxy - The Proxy.

revealType - The Presenter.RevealType.

slot - The slot where to reveal this presenter see GwtEvent.Type and RevealContentHandler.

Method Detail

bind

public final void bind()

Description copied from interface: HandlerContainer

Call this method after the object is constructed in order to bind all its handlers. You should never call HandlerContainer.bind() from the constructor of a non-leaf class since it is meant to be called after the object has been entirely constructed.

When automatic binding is used (see HandlerContainerImpl), this will be called immediately after the object is constructed through Guice/GIN dependency injection mechanism.

If you are not using automatic binding, or if you later call HandlerContainer.unbind() on this object, you will have to call HandlerContainer.bind() manually.

Multiple call to bind will not fail, the class will be bound once.

Specified by:

bind in interface HandlerContainer

Overrides:

bind in class HandlerContainerImpl

unbind

public final void unbind()

Description copied from interface: HandlerContainer

Call this method when you want to release the object and its handlers are not needed anymore. You will have to call HandlerContainer.bind() again manually if you ever want to reuse the object.

Specified by:

unbind in interface HandlerContainer

Overrides:

unbind in class HandlerContainerImpl

forceReveal

public final void forceReveal()

Reveals the presenter, bypassing any service offered by the PlaceManager. Since this method bypasses the PlaceManager it will not:

• Update the browser history
• Check accessibility via the Gatekeeper
• Setup the presenter via prepareFromRequest(PlaceRequest)
• Uses the leave confirmation mechanism (see .PlaceManager#setOnLeaveConfirmation(String) PlaceManager.setOnLeaveConfirmation)

Therefore, to reveal a presenter associated to a ProxyPlace use one of the method provided by the PlaceManager. For more details see Presenter.

getProxy

public final Proxy_ getProxy()

Returns the Proxy attached to this presenter.

Returns:

The Proxy.

useManualReveal

public boolean useManualReveal()

Verifies if this presenter can be revealed automatically or if it is meant to be revealed manually. Normally, the user wants to reveal a presenter manually when it cannot be used until some data is received from the server. For example, a form to edit client details is unusable until all the data for this user has been received. Fetching this data should be done in the prepareFromRequest(PlaceRequest) method.

In order to use manual reveal, override this method to return true. Then, in your prepareFromRequest(com.gwtplatform.mvp.shared.proxy.PlaceRequest), you can either:

• Fetch the data using a ManualRevealCallback, which will automatically reveal the presenter upon success.
• Fetch the data by any other mean and call ProxyPlace.manualReveal(Presenter) when your data is available. In this case you also have to call ProxyPlace.manualRevealFailed() if loading fails, otherwise your application will become unusable.

The default implementation uses automatic reveal, and therefore returns false.

Returns:

true if you want to use manual reveal, or false to use automatic reveal.

prepareFromRequest

public void prepareFromRequest(PlaceRequest request)

Prepare the state of the presenter given the information contained in the PlaceRequest. This method is called when the PlaceManager navigates to this Presenter. You should override the method to extract any parameters you need from the request. Make sure you call your parent's prepareFromRequest(com.gwtplatform.mvp.shared.proxy.PlaceRequest) method.

If your presenter needs to fetch some information from the server while preparing itself, consider using manual reveal. See useManualReveal().

If your presenter does not handle any parameter and does not want to fetch extra information, then there is no need to override this method.

Parameters:

request - The PlaceRequest.

getRevealType

protected Presenter.RevealType getRevealType()

Returns the Presenter.RevealType of this presenter.

Returns:

The Presenter.RevealType.

setRevealType

protected void setRevealType(Presenter.RevealType revealType)

Set the Presenter.RevealType of this presenter. If the parent type is not null, the slot will be ignored in revealInParent().

Parameters:

revealType - The Presenter.RevealType.

getSlot

protected GwtEvent.Type<RevealContentHandler<?>> getSlot()

Returns the slot where this presenter is to be revealed.

Returns:

The slot where to reveal this presenter see GwtEvent.Type and RevealContentHandler.

setSlot

protected void setSlot(GwtEvent.Type<RevealContentHandler<?>> slot)

Set the slot where this presenter is to be revealed. The slot is ignored in revealInParent() if the parent type is not null.

Parameters:

slot - The slot where to reveal this presenter see GwtEvent.Type and RevealContentHandler.

revealInParent

protected void revealInParent()

Requests that the presenter reveal itself in its parent presenter. You can override this method to either fire a RevealContentEvent, a RevealRootContentEvent or a RevealRootLayoutContentEvent.