Eclipse RAP Development Guide (Galileo) - AbstractWidgetLCA (Eclipse Rich Ajax Platform API Specification)

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Eclipse Rich Ajax Platform
Release 1.2

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org.eclipse.rwt.lifecycle
Class AbstractWidgetLCA


java.lang.Object
  
org.eclipse.rwt.lifecycle.AbstractWidgetLCA

All Implemented Interfaces:: ILifeCycleAdapter, IWidgetLifeCycleAdapter

public abstract class AbstractWidgetLCA
extends Object
implements IWidgetLifeCycleAdapter

Abstract implementation of a widget life cycle adapter. All widget LCAs should inherit from this class.

Since:: 1.0

Constructor Summary

AbstractWidgetLCA ()


Method Summary

Rectangle adjustCoordinates ( Widget widget, Rectangle bounds)
          Translates the bounds of a widget that is enclosed in the widget handled by this LCA.

void createResetHandlerCalls ( String typePoolId)
           Writes JavaScript code to the response that resets the client-side state of a disposed widget in order to make it ready for later reuse.

void doRedrawFake ( Control control)
           As a side effect to redraw calls some native widgets trigger events like resize for example.

String getTypePoolId ( Widget widget)
          Returns an id that is used to identify the type of a widget in the client-side widget pool.

abstract void preserveValues ( Widget widget)
          Preserves the current state of the widget in order to be able to keep track of changes.

void render ( Widget widget)
          Writes JavaScript code to the response that renders the changes that has been made to the widget.

abstract void renderChanges ( Widget widget)
          Writes JavaScript code to the response that applies the state changes of the widget to the client.

abstract void renderDispose ( Widget widget)
          Writes JavaScript code to the response that renders the disposal of the widget.

abstract void renderInitialization ( Widget widget)
          Writes JavaScript code to the response that creates a new widget instance and initializes it.

Methods inherited from class java.lang. Object

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

Methods inherited from interface org.eclipse.rwt.lifecycle. IWidgetLifeCycleAdapter

readData

Constructor Detail

AbstractWidgetLCA

public AbstractWidgetLCA()

Method Detail

render

public final void render(
Widget widget)
                  throws 
IOException

Description copied from interface: IWidgetLifeCycleAdapter

Writes JavaScript code to the response that renders the changes that has been made to the widget.

Specified by:: render in interface IWidgetLifeCycleAdapter

Parameters:: widget - the widget to render changes for
Throws:: IOException

adjustCoordinates

public 
Rectangle adjustCoordinates(
Widget widget,
                                   
Rectangle bounds)

Translates the bounds of a widget that is enclosed in the widget handled by this LCA. The default implementation does not modify the given bounds. Subclasses may override.

Parameters:: widget - the enclosed widget whose bounds to adjust; bounds - the actual bounds of the enclosed widget
Returns:: the adjusted bounds

preserveValues

public abstract void preserveValues(
Widget widget)

Description copied from interface: IWidgetLifeCycleAdapter

Preserves the current state of the widget in order to be able to keep track of changes. This method is called after the Read Data phase but before the Process Action phase of the request life cycle. Thus, the client and server state is in sync. By preserving the current state of the widget, it is later possible to identify the properties that have been modified during the processing of the request.

Implementors can use the method IWidgetAdapter.preserve(String, Object). As a rule of thumb, every property that is written in render must be preserved in this method.

Specified by:: preserveValues in interface IWidgetLifeCycleAdapter

Parameters:: widget - the widget, the properties of which are preserved

renderInitialization

public abstract void renderInitialization(
Widget widget)
                                   throws 
IOException

Writes JavaScript code to the response that creates a new widget instance and initializes it. This method is called only once for every widget, before renderChanges is called for the first time.

Parameters:: widget - the widget to initialize
Throws:: IOException

renderChanges

public abstract void renderChanges(
Widget widget)
                            throws 
IOException

Writes JavaScript code to the response that applies the state changes of the widget to the client. Implementations must only render those properties that have been changed during the processing of the current request.

Parameters:: widget - the widget to render changes for
Throws:: IOException

renderDispose

public abstract void renderDispose(
Widget widget)
                            throws 
IOException

Writes JavaScript code to the response that renders the disposal of the widget.

Parameters:: widget - the widget to dispose
Throws:: IOException

createResetHandlerCalls

public void createResetHandlerCalls(
String typePoolId)
                             throws 
IOException

Writes JavaScript code to the response that resets the client-side state of a disposed widget in order to make it ready for later reuse. After this code has been processed the client-side widget should be in a state that is equivalent to a newly created widget.

Subclasses should override this method if pooling is supported by the widget type this LCA belongs to. To activate pooling override getTypePoolId(Widget).

Parameters:: typePoolId - the type pool id of the widget to reset
Throws:: IOException
See Also:: getTypePoolId(Widget)

getTypePoolId

public 
String getTypePoolId(
Widget widget)

Returns an id that is used to identify the type of a widget in the client-side widget pool.

The widget pool is used to store disposed widget instances on the client for later reuse. This is necessary to improve performance and to save client memory. Only widgets with the same type pool id can be reused.

Usually, the fully qualified class name is a suitable return value. In case different sub-types of widget instances should be distinguished, this method must return a different string for every type, e.g. by appending a suffix. If this method returns null, the widget will not be stored in the widget pool and cannot be reused.

Subclasses may override to activate pooling. In case pooling is activated the method createResetHandlerCalls(String) should also be overridden.

Parameters:: widget - the widget to store in the pool
Returns:: the type pool id or null if the widget should not be pooled
See Also:: createResetHandlerCalls(String)

doRedrawFake

public void doRedrawFake(
Control control)

As a side effect to redraw calls some native widgets trigger events like resize for example. To simulate this behaviour subclasses may override this method. The method takes as parameter type Control, since the redraw methods are only available at the Control subclasses of Widgets.

Note that the redraw fake takes place between the process action and the render phase.

Parameters:: control - the control on which redraw was called.