org.eclipse.gef4.layout.listeners

Interface IGraphStructureListener

All Known Implementing Classes:

IGraphStructureListener.Stub

public interface IGraphStructureListener

An IGraphStructureListener is notified about structural changes, i.e. the addition/removal of INodeLayouts and IConnectionLayouts.

Nested Class Summary

Nested Classes

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

Method Summary

Modifier and Type	Method and Description
boolean	connectionAdded(ILayoutContext context, IConnectionLayout connection) This method is called whenever a connection is added to a context.
boolean	connectionRemoved(ILayoutContext context, IConnectionLayout connection) This method is called whenever a connection is removed from a context.
boolean	nodeAdded(ILayoutContext context, INodeLayout node) This method is called whenever a node is added to a context.
boolean	nodeRemoved(ILayoutContext context, INodeLayout node) This method is called whenever a node is removed from a context.

Method Detail

nodeAdded

boolean nodeAdded(ILayoutContext context,
                  INodeLayout node)

This method is called whenever a node is added to a context. No separate events will be fired for eventual connections adjacent to the added node. If true is returned, it means that the receiving listener has intercepted this event. Intercepted events will not be passed to the rest of the listeners. If the event is not intercepted by any listener, ILayoutAlgorithm.applyLayout(boolean) will be called on the context's main algorithm.

Parameters:

context - the layout context that fired the event

node - the added node

Returns:

true if no dynamic layout should be applied afterwards.

nodeRemoved

boolean nodeRemoved(ILayoutContext context,
                    INodeLayout node)

This method is called whenever a node is removed from a context. No separate events will be fired for eventual connections adjacent to the removed node. 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 IGraphStructureListeners return false.

Parameters:

context - the context that fired the event

node - the removed node

Returns:

true if no dynamic layout should be applied afterwards.

connectionAdded

boolean connectionAdded(ILayoutContext context,
                        IConnectionLayout connection)

This method is called whenever a connection is added to a context. It can be assumed that both source and target nodes of the added connection already exist in the context.

This method will be called only if both nodes connected by added connection lay directly in the node container owned by the notifying 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 IGraphStructureListeners return false.

Parameters:

context - the context that fired the event

connection - the added connection

Returns:

true if no dynamic layout should be applied afterwards.

connectionRemoved

boolean connectionRemoved(ILayoutContext context,
                          IConnectionLayout connection)

This method is called whenever a connection is removed from a context. It can be assumed that both source and target nodes of the removed connection still exist in the context and will not be removed along with it.

This method will be called only if both nodes connected by removed connection lay directly in the node container owned by the notifying 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 IGraphStructureListeners return false.

Parameters:

context - the context that fired the event

connection - the added connection

Returns:

true if no dynamic layout should be applied afterwards.