org.metawidget.layout.iface.AdvancedLayout Maven / Gradle / Ivy
// Metawidget
//
// This file is dual licensed under both the LGPL
// (http://www.gnu.org/licenses/lgpl-2.1.html) and the EPL
// (http://www.eclipse.org/org/documents/epl-v10.php). As a
// recipient of Metawidget, you may choose to receive it under either
// the LGPL or the EPL.
//
// Commercial licenses are also available. See http://metawidget.org
// for details.
package org.metawidget.layout.iface;
/**
* Common interface implemented by all AdvancedLayouts. AdvancedLayouts can hook into additional
* lifecycle events.
*
* There are advantages to keeping the vanilla Layout interface as a single-method
* interface: First, it alleviates the need for a BaseLayout or
* LayoutAdapter class (to provide default implementations for subclasses who don't
* override all the methods); second, it makes Layout an example of the Strategy
* pattern; third, it makes Layout amenable to automatic function objects (part of
* closures in Java 7). This latter point is more of a concession to consistency with
* WidgetProcessor and the other interfaces in the pipeline, but may still prove
* useful.
*
* @author Richard Kennard
*/
public interface AdvancedLayout
extends Layout {
//
// Methods
//
/**
* Event called at the start of the widget building process, before the
* WidgetBuilder is called. Layouts may wish to act on this event to
* initialize themselves ready for processing, or to perform 'outermost-container-only'
* processing, such as adding facets. This event is only called once per inspection, not once
* per widget built.
*
* @param metawidget
* the parent Metawidget. Never null
*/
void onStartBuild( M metawidget );
/**
* Initialise the given container, using the given Metawidget to access additional services if
* needed (such as state saving).
*
* @param container
* the container to layout. This is often the same as the given Metawidget
* @param metawidget
* the parent Metawidget. Never null
*/
void startContainerLayout( C container, M metawidget );
/**
* Finish the given container, using the given Metawidget to access additional services if
* needed (such as state saving).
*
* @param container
* the container to layout. This is often the same as the given Metawidget
* @param metawidget
* the Metawidget to use to access additional services. Never null
*/
void endContainerLayout( C container, M metawidget );
/**
* Event called at the end of widget building, after all widgets have been built and added to
* the Layout. Layouts may wish to act on this event to clean
* themselves up after processing, or to perform 'outermost-container-only' processing, such as
* adding facets. This event is only called once per inspection, not once per widget built.
*
* @param metawidget
* the parent Metawidget. Never null
*/
void onEndBuild( M metawidget );
}