Package org.eclipse.ui.actions

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
    Since:
    3.0

    • Constructor Detail

      • BaseSelectionListenerAction

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

    • Method Detail

      • 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).
        Returns:
        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.

        Parameters:
        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
        Parameters:
        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.

        Parameters:
        selection - the new selection
        Returns:
        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
        Overrides:
        runWithEvent in class Action
        Parameters:
        event - the SWT event which triggered this action being run
        See Also:
        How radio buttons are handled, How check boxes are handled