actioncontributionitem.java

jfa2ce 源码帮助开发人员更好的理解运用

        return action;
    }

    /**
     * Returns the listener for SWT button widget events.
     * 
     * @return a listener for button events
     */
    private Listener getButtonListener() {
        if (buttonListener == null) {
            buttonListener = new Listener() {
                public void handleEvent(Event event) {
                    switch (event.type) {
                    case SWT.Dispose:
                        handleWidgetDispose(event);
                        break;
                    case SWT.Selection:
                        Widget ew = event.widget;
                        if (ew != null) {
                            handleWidgetSelection(event, ((Button) ew)
                                    .getSelection());
                        }
                        break;
                    }
                }
            };
        }
        return buttonListener;
    }

    /**
     * Returns the listener for SWT menu item widget events.
     * 
     * @return a listener for menu item events
     */
    private Listener getMenuItemListener() {
        if (menuItemListener == null) {
            menuItemListener = new Listener() {
                public void handleEvent(Event event) {
                    switch (event.type) {
                    case SWT.Dispose:
                        handleWidgetDispose(event);
                        break;
                    case SWT.Selection:
                        Widget ew = event.widget;
                        if (ew != null) {
                            handleWidgetSelection(event, ((MenuItem) ew)
                                    .getSelection());
                        }
                        break;
                    }
                }
            };
        }
        return menuItemListener;
    }

    /**
     * Returns the presentation mode, which is the bitwise-or of the 
     * <code>MODE_*</code> constants.  The default mode setting is 0, meaning
     * that for menu items, both text and image are shown (if present), but for
     * tool items, the text is shown only if there is no image.
     * 
     * @return the presentation mode settings
     * 
     * @since 3.0
     */
    public int getMode() {
        return mode;
    }

    /**
     * Returns the listener for SWT tool item widget events.
     * 
     * @return a listener for tool item events
     */
    private Listener getToolItemListener() {
        if (toolItemListener == null) {
            toolItemListener = new Listener() {
                public void handleEvent(Event event) {
                    switch (event.type) {
                    case SWT.Dispose:
                        handleWidgetDispose(event);
                        break;
                    case SWT.Selection:
                        Widget ew = event.widget;
                        if (ew != null) {
                            handleWidgetSelection(event, ((ToolItem) ew)
                                    .getSelection());
                        }
                        break;
                    }
                }
            };
        }
        return toolItemListener;
    }

    /**
     * Handles a widget dispose event for the widget corresponding to this item.
     */
    private void handleWidgetDispose(Event e) {
        // Check if our widget is the one being disposed.
        if (e.widget == widget) {
            // Dispose of the menu creator.
            if (action.getStyle() == IAction.AS_DROP_DOWN_MENU) {
                IMenuCreator mc = action.getMenuCreator();
                if (mc != null) {
                    mc.dispose();
                }
            }

            // Unhook all of the listeners.
            action.removePropertyChangeListener(propertyListener);
            if (action != null) {
                String commandId = action.getActionDefinitionId();
                ExternalActionManager.ICallback callback = ExternalActionManager
                        .getInstance().getCallback();

                if ((callback != null) && (commandId != null)) {
                    callback.removePropertyChangeListener(commandId,
                            actionTextListener);
                }
            }

            // Clear the widget field.
            widget = null;
            
            disposeOldImages();
        }
    }

    /**
     * Handles a widget selection event.
     */
    private void handleWidgetSelection(Event e, boolean selection) {

        Widget item = e.widget;
        if (item != null) {
            int style = item.getStyle();

            if ((style & (SWT.TOGGLE | SWT.CHECK)) != 0) {
                if (action.getStyle() == IAction.AS_CHECK_BOX) {
                    action.setChecked(selection);
                }
            } else if ((style & SWT.RADIO) != 0) {
                if (action.getStyle() == IAction.AS_RADIO_BUTTON) {
                    action.setChecked(selection);
                }
            } else if ((style & SWT.DROP_DOWN) != 0) {
                if (e.detail == 4) { // on drop-down button
                    if (action.getStyle() == IAction.AS_DROP_DOWN_MENU) {
                        IMenuCreator mc = action.getMenuCreator();
                        ToolItem ti = (ToolItem) item;
                        // we create the menu as a sub-menu of "dummy" so that we can use
                        // it in a cascading menu too.
                        // If created on a SWT control we would get an SWT error...
                        //Menu dummy= new Menu(ti.getParent());
                        //Menu m= mc.getMenu(dummy);
                        //dummy.dispose();
                        if (mc != null) {
                            Menu m = mc.getMenu(ti.getParent());
                            if (m != null) {
                                // position the menu below the drop down item
                                Rectangle b = ti.getBounds();
                                Point p = ti.getParent().toDisplay(
                                        new Point(b.x, b.y + b.height));
                                m.setLocation(p.x, p.y); // waiting for SWT 0.42
                                m.setVisible(true);
                                return; // we don't fire the action
                            }
                        }
                    }
                }
            }

            // Ensure action is enabled first.
            // See 1GAN3M6: ITPUI:WINNT - Any IAction in the workbench can be executed while disabled.
            if (action.isEnabled()) {
                boolean trace = Policy.TRACE_ACTIONS;

                long ms = System.currentTimeMillis();
                if (trace) {
					System.out.println("Running action: " + action.getText()); //$NON-NLS-1$
				}

                action.runWithEvent(e);

                if (trace) {
					System.out.println((System.currentTimeMillis() - ms)
                            + " ms to run action: " + action.getText()); //$NON-NLS-1$
				}
            }
        }
    }

    /* (non-Javadoc)
     * Method declared on Object.
     */
    public int hashCode() {
        return action.hashCode();
    }

    /**
     * Returns whether the given action has any images.
     * 
     * @param actionToCheck the action
     * @return <code>true</code> if the action has any images, <code>false</code> if not
     */
    private boolean hasImages(IAction actionToCheck) {
        return actionToCheck.getImageDescriptor() != null
                || actionToCheck.getHoverImageDescriptor() != null
                || actionToCheck.getDisabledImageDescriptor() != null;
    }

    /**
     * Returns whether the command corresponding to this action
     * is active.
     */
    private boolean isCommandActive() {
        IAction actionToCheck = getAction();

        if (actionToCheck != null) {
            String commandId = actionToCheck.getActionDefinitionId();
            ExternalActionManager.ICallback callback = ExternalActionManager
                    .getInstance().getCallback();

            if (callback != null) {
				return callback.isActive(commandId);
			}
        }
        return true;
    }

    /**
     * The action item implementation of this <code>IContributionItem</code>
     * method returns <code>true</code> for menu items and <code>false</code>
     * for everything else.
     */
    public boolean isDynamic() {
        if (widget instanceof MenuItem) {
            //Optimization. Only recreate the item is the check or radio style has changed. 
            boolean itemIsCheck = (widget.getStyle() & SWT.CHECK) != 0;
            boolean actionIsCheck = getAction() != null
                    && getAction().getStyle() == IAction.AS_CHECK_BOX;
            boolean itemIsRadio = (widget.getStyle() & SWT.RADIO) != 0;
            boolean actionIsRadio = getAction() != null
                    && getAction().getStyle() == IAction.AS_RADIO_BUTTON;
            return (itemIsCheck != actionIsCheck)
                    || (itemIsRadio != actionIsRadio);
        }
        return false;
    }

    /* (non-Javadoc)
     * Method declared on IContributionItem.
     */
    public boolean isEnabled() {
        return action != null && action.isEnabled();
    }

    /**
     * Returns <code>true</code> if this item is allowed to enable,
     * <code>false</code> otherwise.
     * 
     * @return if this item is allowed to be enabled
     * @since 2.0
     */
    protected boolean isEnabledAllowed() {
        if (getParent() == null) {
			return true;
		}
        Boolean value = getParent().getOverrides().getEnabled(this);
        return (value == null) ? true : value.booleanValue();
    }

    /**
     * The <code>ActionContributionItem</code> implementation of this 
     * <code>ContributionItem</code> method extends the super implementation
     * by also checking whether the command corresponding to this action is active.
     */
    public boolean isVisible() {
        return super.isVisible() && isCommandActive();
    }

    /**
     * Sets the presentation mode, which is the bitwise-or of the 
     * <code>MODE_*</code> constants.
     * 
     * @param mode the presentation mode settings
     * 
     * @since 3.0
     */
    public void setMode(int mode) {
        this.mode = mode;
        update();
    }

    /**
     * The action item implementation of this <code>IContributionItem</code>
     * method calls <code>update(null)</code>.
     */
    public final void update() {
        update(null);
    }

    /**
     * Synchronizes the UI with the given property.
     *
     * @param propertyName the name of the property, or <code>null</code> meaning all applicable
     *   properties 
     */
    public void update(String propertyName) {
        if (widget != null) {
            // determine what to do			
            boolean textChanged = propertyName == null
                    || propertyName.equals(IAction.TEXT);
            boolean imageChanged = propertyName == null
                    || propertyName.equals(IAction.IMAGE);
            boolean tooltipTextChanged = propertyName == null
                    || propertyName.equals(IAction.TOOL_TIP_TEXT);
            boolean enableStateChanged = propertyName == null
                    || propertyName.equals(IAction.ENABLED)
                    || propertyName
                            .equals(IContributionManagerOverrides.P_ENABLED);
            boolean checkChanged = (action.getStyle() == IAction.AS_CHECK_BOX || action
                    .getStyle() == IAction.AS_RADIO_BUTTON)
                    && (propertyName == null || propertyName
                            .equals(IAction.CHECKED));

            if (widget instanceof ToolItem) {
                ToolItem ti = (ToolItem) widget;
                String text = action.getText();
                // the set text is shown only if there is no image or if forced by MODE_FORCE_TEXT
                boolean showText = text != null
                        && ((getMode() & MODE_FORCE_TEXT) != 0 || !hasImages(action));

                // only do the trimming if the text will be used
                if (showText && text != null) {
                    text = Action.removeAcceleratorText(text);
                    text = Action.removeMnemonics(text);
                }

                if (textChanged) {
                    String textToSet = showText ? text : ""; //$NON-NLS-1$
                    boolean rightStyle = (ti.getParent().getStyle() & SWT.RIGHT) != 0;
                    if (rightStyle || !ti.getText().equals(textToSet)) {
                        // In addition to being required to update the text if it
                        // gets nulled out in the action, this is also a workaround 
                        // for bug 50151: Using SWT.RIGHT on a ToolBar leaves blank space
                        ti.setText(textToSet);
                    }