org.eclipse.gef4.layout.listeners

Interface IContextListener

All Known Implementing Classes:

IContextListener.Stub

public interface IContextListener

An IContextListener is notified about changes to context attributes such as the LayoutProperties.BOUNDS_PROPERTY which limits the area where nodes can be placed by layout algorithms, the LayoutProperties.PRUNING_ENABLED_PROPERTY which defines whether nodes can be pruned, and the LayoutProperties.DYNAMIC_LAYOUT_ENABLED_PROPERTY which defines whether layout algorithms are allowed to perform a layout pass in reaction to layout context events.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	IContextListener.Stub A stub implementation of the IContextListener which contains empty implementations of the specified methods.

Method Summary

Modifier and Type	Method and Description
void	backgroundEnableChanged(ILayoutContext context) This method is called whenever background layout is enabled or disabled in a layout context.
boolean	boundsChanged(ILayoutContext context) This method is called whenever the bounds available in a layout context change.
boolean	pruningEnablementChanged(ILayoutContext context) This method is called whenever graph pruning is enabled or disabled in a layout context.

Method Detail

boundsChanged

boolean boundsChanged(ILayoutContext context)

This method is called whenever the bounds available in a layout context change. If true is returned, no dynamic layout will be applied after notifying all listeners, i.e. a dynamic layout pass will only be applied when all registered IContextListeners return false.

Parameters:

context - the layout context that fired the event

Returns:

true if no dynamic layout should be applied afterwards.

pruningEnablementChanged

boolean pruningEnablementChanged(ILayoutContext context)

This method is called whenever graph pruning is enabled or disabled in a layout context. If true is returned, no dynamic layout will be applied after notifying all listeners, i.e. a dynamic layout pass will only be applied when all registered IContextListeners return false.

Parameters:

context - the layout context that fired the event

Returns:

true if no dynamic layout should be applied afterwards.

backgroundEnableChanged

void backgroundEnableChanged(ILayoutContext context)

This method is called whenever background layout is enabled or disabled in a layout context. If the receiving listener is related to a layout algorithm that performs layout in reaction to events, it should turn automatic flush of changes on or off. Also, eventual additional threads responsible for layout should be stopped or started accordingly.

Parameters:

context - the layout context that fired the event