Interface EditPart

All Superinterfaces:
IAdaptable
All Known Subinterfaces:
ConnectionEditPart, GraphicalEditPart, IScrollableEditPart, NodeEditPart, RootEditPart, TreeEditPart
All Known Implementing Classes:
AbstractConnectionEditPart, AbstractEditPart, AbstractGraphicalEditPart, AbstractTreeEditPart, FreeformGraphicalRootEditPart, GraphicalRootEditPart, RootTreeEditPart, ScalableFreeformRootEditPart, ScalableRootEditPart, SimpleRootEditPart

public interface EditPart extends IAdaptable
EditParts are the building blocks of GEF Viewers. As the Controller, an EditPart ties the application's model to a visual representation. EditParts are responsible for making changes to the model. EditParts typically control a single model object or a coupled set of object. Visual representations include Figures and TreeItems. Model objects are often composed of other objects that the User will interact with. Similarly, EditParts can be composed of or have references to other EditParts.

The creator of an EditPart should call only setModel(Object). The remaining API is used mostly by Tools, EditPolicies, and other EditParts. CHANGES are made to the model, not the EditPart.

Most interaction with EditParts is achieved using Requests. A Request specifies the type of interaction. Requests are used in targeting, filtering the selection (using understandsRequest(Request)), graphical showSourceFeedback(Request) feedback, and most importantly, obtaining commands. Only Commands should change the model.

IMPORTANT: This interface is not intended to be implemented by clients. Clients should inherit from AbstractEditPart. New methods may be added in the future.

  • Field Details

    • SELECTED_NONE

      static final int SELECTED_NONE
      Used to indicate no selection
      See Also:
    • SELECTED

      static final int SELECTED
      Used to indicate non-primary selection
      See Also:
    • SELECTED_PRIMARY

      static final int SELECTED_PRIMARY
      Used to indicate primary selection, or "Anchor" selection. Primary selection is defined as the last object selected.
      See Also:
  • Method Details

    • activate

      void activate()
      Activates the EditPart. EditParts that observe a dynamic model or support editing must be active. Called by the managing EditPart, or the Viewer in the case of the RootEditPart. This method may be called again once deactivate() has been called.

      During activation the receiver should:

      • begin to observe its model if appropriate, and should continue the observation until deactivate() is called.
      • activate all of its EditPolicies. EditPolicies may also observe the model, although this is rare. But it is common for EditPolicies to contribute additional visuals, such as selection handles or feedback during interactions. Therefore it is necessary to tell the EditPolicies when to start doing this, and when to stop.
      • call activate() on the EditParts it manages. This includes its children, and for GraphicalEditParts, its source connections.
    • addEditPartListener

      void addEditPartListener(EditPartListener listener)
      Adds a listener to the EditPart. Duplicate calls result in duplicate notification.
      Parameters:
      listener - the Listener
    • addNotify

      void addNotify()
      Called after the EditPart has been added to its parent. This is used to indicate to the EditPart that it should refresh itself for the first time.
    • deactivate

      void deactivate()
      Deactivates the EditPart. EditParts that observe a dynamic model or support editing must be active. deactivate() is guaranteed to be called when an EditPart will no longer be used. Called by the managing EditPart, or the Viewer in the case of the RootEditPart. This method may be called multiple times.

      During deactivation the receiver should:

      • remove all listeners that were added in activate()
      • deactivate all of its EditPolicies. EditPolicies may be contributing additional visuals, such as selection handles or feedback during interactions. Therefore it is necessary to tell the EditPolicies when to start doing this, and when to stop.
      • call deactivate() on the EditParts it manages. This includes its children, and for GraphicalEditParts, its source connections.
    • eraseSourceFeedback

      void eraseSourceFeedback(Request request)
      Erases source feedback for the specified Request. A Request is used to describe the type of source feedback that should be erased. This method should only be called once to erase feedback. It should only be called in conjunction with a prior call to showSourceFeedback(Request).
      Parameters:
      request - the type of feedback that is being erased
    • eraseTargetFeedback

      void eraseTargetFeedback(Request request)
      Erases target feedback for the specified Request. A Request is used to describe the type of target feedback that should be erased. This method should only be called once to erase feedback. It should only be called in conjunction with a prior call to showTargetFeedback(Request).
      Parameters:
      request - the type of feedback that is being erased
    • getChildren

      List getChildren()
      Returns the List of children EditParts. This method should rarely be called, and is only made public so that helper objects of this EditPart, such as EditPolicies, can obtain the children. The returned List may be by reference, and should never be modified.
      Returns:
      a List of children
    • getCommand

      Command getCommand(Request request)
      Returns the Command to perform the specified Request or null.
      Parameters:
      request - describes the Command being requested
      Returns:
      null or a Command
    • getDragTracker

      DragTracker getDragTracker(Request request)
      Returns a DragTracker for dragging this EditPart. The SelectionTool is the only Tool by default that calls this method. The SelectionTool will use a SelectionRequest to provide information such as which mouse button is down, and what modifier keys are pressed.
      Parameters:
      request - a Request indicating the context of the drag
      Returns:
      null or a DragTracker
    • getEditPolicy

      EditPolicy getEditPolicy(Object key)
      Parameters:
      key - the key identifying the EditPolicy
      Returns:
      null or the EditPolicy installed with the given key
    • getModel

      Object getModel()
      Returns the primary model object that this EditPart represents. EditParts may correspond to more than one model object, or even no model object. In practice, the Object returned is used by other EditParts to identify this EditPart. In addition, EditPolicies probably rely on this method to build Commands that operate on the model.
      Returns:
      null or the primary model object
    • getParent

      EditPart getParent()
      Returns the parent EditPart. This method should only be called internally or by helpers such as EditPolicies.
      Returns:
      null or the parent EditPart
    • getRoot

      RootEditPart getRoot()
      Returns the RootEditPart. This method should only be called internally or by helpers such as edit policies. The root can be used to get the viewer.
      Returns:
      null or the RootEditPart
    • getSelected

      int getSelected()
      Returns the selected state of this EditPart. This method should only be called internally or by helpers such as EditPolicies.
      Returns:
      one of:
    • getTargetEditPart

      EditPart getTargetEditPart(Request request)
      Return the EditPart that should be used as the target for the specified Request. Tools will generally call this method with the mouse location so that the receiver can implement drop targeting. Typically, if this EditPart is not the requested target (for example, this EditPart is not a composite), it will forward the call to its parent.
      Parameters:
      request - the type of target being requested
      Returns:
      null or the target
    • getViewer

      EditPartViewer getViewer()
      Convenience method for returning the EditPartViewer for this part.
      Returns:
      the EditPartViewer or null
    • hasFocus

      boolean hasFocus()
      Returns true if this EditPart has focus. The focus EditPart is a property of the EditPartViewer. The Viewer keeps this property in sync with its focus.
      Returns:
      true if the EditPart has focus
      See Also:
    • installEditPolicy

      void installEditPolicy(Object role, EditPolicy editPolicy)
      Installs an EditPolicy for a specified role. A role is is simply an Object used to identify the EditPolicy. An example of a role is layout. EditPolicy.LAYOUT_ROLE is generally used as the key for this EditPolicy. null is a valid value for reserving a location.
      Parameters:
      role - an identifier used to key the EditPolicy
      editPolicy - the EditPolicy
    • isActive

      boolean isActive()
      returns true if the EditPart is active. Editparts are active after activate() is called, and until deactivate() is called.
      Returns:
      true when active
    • isSelectable

      boolean isSelectable()
      Returns true if the EditPart is selectable. A selectable EditPart may be selected as a result of the SelectionTool receiving a mouse down, or as a result of the User pressing a key to change selection.
      Returns:
      true if the receiver can be selected
    • performRequest

      void performRequest(Request request)
      Performs the specified Request. This method can be used to send a generic message to an EditPart. If the EditPart interprets this request to mean make a change in the model, it should still use Commands and the CommandStack so that the change is undoable. The CommandStack is available from the EditDomain.
      Parameters:
      request - the request to be performed
    • refresh

      void refresh()
      Called to force a refresh of this EditPart. All visuals properties will be updated, as well as structural features like children.
    • removeEditPartListener

      void removeEditPartListener(EditPartListener listener)
      Removes the first occurance of the specified listener from the list of listeners. Does nothing if the listener was not present.
      Parameters:
      listener - the listener being removed
    • removeEditPolicy

      void removeEditPolicy(Object role)
      Removes the EditPolicy for the given role. The EditPolicy is deactivated if it is active. The position for that role is maintained with null in the place of the old EditPolicy.
      Parameters:
      role - the key identifying the EditPolicy to be removed
      See Also:
    • removeNotify

      void removeNotify()
      Called when the EditPart is being permanently removed from its EditPartViewer. This indicates that the EditPart will no longer be in the Viewer, and therefore should remove itself from the Viewer. This method is not called when a Viewer is disposed. It is only called when the EditPart is removed from its parent. This method is the inverse of addNotify()
    • setFocus

      void setFocus(boolean hasFocus)
      Set the focus property to reflect the value in the EditPartViewer. Focus is determined by the EditPartViewer.

      Focus is considered to be part of the selected state, changing this value will fire EditPartListener.selectedStateChanged(EditPart).

      IMPORTANT: This method should only be called by the EditPartViewer.

      Parameters:
      hasFocus - boolean indicating if this part has focus
    • setModel

      void setModel(Object model)
      Sets the model. This method is made public to facilitate the use of EditPartFactories .

      IMPORTANT: This method should only be called once.

      Parameters:
      model - the Model
    • setParent

      void setParent(EditPart parent)
      Sets the parent. This should only be called by the parent EditPart.
      Parameters:
      parent - the parent EditPart
    • setSelected

      void setSelected(int value)
      Sets the selected state property to reflect the selection in the EditPartViewer. Fires selectedStateChanged(EditPart) to any EditPartListeners. Selection is maintained by the EditPartViewer.

      IMPORTANT: This method should only be called by the EditPartViewer.

      Parameters:
      value - an enum indicating the selected state
      See Also:
    • showSourceFeedback

      void showSourceFeedback(Request request)
      Shows or updates source feedback for the given request. This method may be called multiple times so that the feedback can be updated for changes in the request, such as the mouse location changing.
      Parameters:
      request - request describing the type of feedback
    • showTargetFeedback

      void showTargetFeedback(Request request)
      Shows or updates target feedback for the given request. This method can be called multiple times so that the feedback can be updated for changes in the request, such as the mouse location changing.
      Parameters:
      request - request describing the type of feedback
    • understandsRequest

      boolean understandsRequest(Request request)
      Used to filter EditParts out of the current selection. If an operation is going to be performed on the current selection, the selection can first be culled to remove EditParts that do not participate in the operation. For example, when aligning the left edges of GraphicalEditParts, it makes sense to ignore any selected ConnectionEditParts, as they cannot be aligned.
      Parameters:
      request - a Request describing an operation of some type
      Returns:
      true if Request is understood