Package edu.cnu.mdi.view

Class InfoDialogHelper

java.lang.Object
edu.cnu.mdi.view.InfoDialogHelper
public class InfoDialogHelper extends Object
Utility for displaying AbstractViewInfo content in a lightweight, non-modal, non-stealing info dialog.

Deduplication

Only one info dialog per owner window is kept open at a time. Calling showInfoDialog(java.awt.Component, edu.cnu.mdi.view.AbstractViewInfo) while a dialog is already open for the same owner brings the existing dialog to the front and replaces its content with the new AbstractViewInfo. This prevents multiple identical dialogs accumulating when the user clicks an info button repeatedly, and allows the same dialog shell to serve different views as the user navigates.

Ownership and memory management

The owner-to-dialog mapping uses a WeakHashMap keyed on the Window ancestor of the parent component. When an owner window is garbage-collected its entry is removed automatically, so the map never prevents window cleanup. A WindowAdapter on each dialog also removes its entry when the dialog is explicitly closed, so that the next call creates a fresh dialog rather than reusing a disposed one.

Caller contract

  • Must be called on the Swing EDT.
  • Callers that hold a reference to the returned JDialog and wish to close it programmatically should call Window.dispose() on it; the helper will detect the disposal and remove the entry from its tracking map so that a fresh dialog can be shown later.

  • Method Details

    • showInfoDialog

      public static JDialog showInfoDialog(Component parent, AbstractViewInfo info)
      Show an info dialog for the given AbstractViewInfo, reusing any existing dialog that belongs to the same owner window.

      If a dialog for this owner is already open and has not been disposed, it is brought to the front and its HTML content is updated to info. The scroll position is reset to the top. This allows the same dialog to be reused when the user opens info for different views without closing the panel in between.

      When no reusable dialog exists for this owner, a new one is created. It is configured as:

      • Modeless (Dialog.ModalityType.MODELESS) — does not block the parent window.
      • Non-focus-stealing (autoRequestFocus = false, focusableWindowState = false) — clicking the info button does not shift keyboard focus away from the main window.
      • Window.Type.UTILITY — suppresses the taskbar entry on platforms that honour this type.

      Must be called on the Swing EDT.

      Parameters:
      parent - the component relative to which the dialog is positioned; must not be null
      info - the view-info object whose HTML to display; must not be null
      Returns:
      the shown (possibly pre-existing) dialog; never null