Class BaseSelectionListenerAction

All Implemented Interfaces:
IAction, ISelectionChangedListener
Direct Known Subclasses:
ExportResourcesAction, ImportResourcesAction, ModelParticipantAction, SelectionListenerAction, SynchronizeModelAction

public abstract class BaseSelectionListenerAction extends Action implements ISelectionChangedListener
The abstract superclass for actions that listen to selection change events. This implementation tracks the current selection (see getStructuredSelection) and provides a convenient place to monitor selection changes that could affect the availability of the action.

Subclasses must implement the following IAction method:

  • run - to do the action's work

Subclasses may extend the updateSelection method to update the action determine its availability based on the current selection.

The object instantiating the subclass is responsible for registering the instance with a selection provider. Alternatively, the object can notify the subclass instance directly of a selection change using the methods:

  • selectionChanged(IStructuredSelection) - passing the selection
  • selectionChanged(ISelectionChangedEvent) - passing the selection change event
  • Constructor Details

    • BaseSelectionListenerAction

      protected BaseSelectionListenerAction(String text)
      Creates a new action with the given text.
      text - the string used as the text for the action, or null if there is no text
  • Method Details

    • clearCache

      protected void clearCache()
      Clears any cached state associated with the selection. Called when the selection changes.

      The BaseSelectionListenerAction implementation of this method does nothing. Subclasses may override.

    • getStructuredSelection

      public IStructuredSelection getStructuredSelection()
      Returns the current structured selection in the workbench, or an empty selection if nothing is selected or if selection does not include objects (for example, raw text).
      the current structured selection in the workbench
    • selectionChanged

      public final void selectionChanged(IStructuredSelection selection)
      Notifies this action that the given structured selection has changed.

      The BaseSelectionListenerAction implementation of this method records the given selection for future reference and calls updateSelection, updating the enable state of this action based on the outcome. Subclasses should override updateSelection to react to selection changes.

      selection - the new selection
    • selectionChanged

      public final void selectionChanged(SelectionChangedEvent event)
      The BaseSelectionListenerAction implementation of this ISelectionChangedListener method calls selectionChanged(IStructuredSelection) assuming the selection is a structured one. Subclasses should override the updateSelection method to react to selection changes.
      Specified by:
      selectionChanged in interface ISelectionChangedListener
      event - event object describing the change
    • updateSelection

      protected boolean updateSelection(IStructuredSelection selection)
      Updates this action in response to the given selection.

      The BaseSelectionListenerAction implementation of this method returns true. Subclasses may extend to react to selection changes; however, if the super method returns false, the overriding method must also return false.

      selection - the new selection
      true if the action should be enabled for this selection, and false otherwise
    • runWithEvent

      public void runWithEvent(Event event)
      Description copied from class: Action
      The default implementation of this IAction method ignores the event argument, and simply calls run(). Subclasses should override this method if they need information from the triggering event, or override run() if not.
      Specified by:
      runWithEvent in interface IAction
      runWithEvent in class Action
      event - the SWT event which triggered this action being run
      See Also: