org.eclipse.jface.action.ActionContributionItem.java Source code

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/*******************************************************************************
 * Copyright (c) 2000, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Jan-Ove Weichel <janove.weichel@vogella.com> - Bug 475879
 *******************************************************************************/
package org.eclipse.jface.action;

import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.commands.NotEnabledException;
import org.eclipse.jface.action.ExternalActionManager.IBindingManagerCallback;
import org.eclipse.jface.bindings.Trigger;
import org.eclipse.jface.bindings.TriggerSequence;
import org.eclipse.jface.bindings.keys.IKeyLookup;
import org.eclipse.jface.bindings.keys.KeyLookupFactory;
import org.eclipse.jface.bindings.keys.KeyStroke;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.resource.LocalResourceManager;
import org.eclipse.jface.resource.ResourceManager;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.Policy;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.jface.util.Util;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Item;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;
import org.eclipse.swt.widgets.ToolBar;
import org.eclipse.swt.widgets.ToolItem;
import org.eclipse.swt.widgets.Widget;

/**
 * A contribution item which delegates to an action.
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 * @noextend This class is not intended to be subclassed by clients.
 */
public class ActionContributionItem extends ContributionItem {

    /**
     * Mode bit: Show text on tool items or buttons, even if an image is
     * present. If this mode bit is not set, text is only shown on tool items if
     * there is no image present.
     *
     * @since 3.0
     */
    public static int MODE_FORCE_TEXT = 1;

    /** a string inserted in the middle of text that has been shortened */
    private static final String ellipsis = "..."; //$NON-NLS-1$

    /**
     * Stores the result of the action. False when the action returned failure.
     */
    private Boolean result = null;

    private static boolean USE_COLOR_ICONS = true;

    /**
     * Returns whether color icons should be used in toolbars.
     *
     * @return <code>true</code> if color icons should be used in toolbars,
     *         <code>false</code> otherwise
     */
    public static boolean getUseColorIconsInToolbars() {
        return USE_COLOR_ICONS;
    }

    /**
     * Sets whether color icons should be used in toolbars.
     *
     * @param useColorIcons
     *            <code>true</code> if color icons should be used in toolbars,
     *            <code>false</code> otherwise
     */
    public static void setUseColorIconsInToolbars(boolean useColorIcons) {
        USE_COLOR_ICONS = useColorIcons;
    }

    /**
     * The presentation mode.
     */
    private int mode = 0;

    /**
     * The action.
     */
    private IAction action;

    /**
     * The listener for changes to the text of the action contributed by an
     * external source.
     */
    private final IPropertyChangeListener actionTextListener = event -> update(event.getProperty());

    /**
     * Remembers all images in use by this contribution item
     */
    private LocalResourceManager imageManager;

    /**
     * Listener for SWT button widget events.
     */
    private Listener buttonListener;

    /**
     * Listener for SWT menu item widget events.
     */
    private Listener menuItemListener;

    /**
     * Listener for action property change notifications.
     */
    private final IPropertyChangeListener propertyListener = event -> actionPropertyChange(event);

    /**
     * Listener for SWT tool item widget events.
     */
    private Listener toolItemListener;

    /**
     * The widget created for this item; <code>null</code> before creation and
     * after disposal.
     */
    private Widget widget = null;

    private Listener menuCreatorListener;

    /**
     * Creates a new contribution item from the given action. The id of the
     * action is used as the id of the item.
     *
     * @param action
     *            the action
     */
    public ActionContributionItem(IAction action) {
        super(action.getId());
        this.action = action;
    }

    /**
     * Handles a property change event on the action (forwarded by nested
     * listener).
     */
    private void actionPropertyChange(final PropertyChangeEvent e) {
        // This code should be removed. Avoid using free asyncExec

        if (isVisible() && widget != null) {
            Display display = widget.getDisplay();
            if (display.getThread() == Thread.currentThread()) {
                update(e.getProperty());
            } else {
                display.asyncExec(() -> update(e.getProperty()));
            }

        }
    }

    /**
     * Compares this action contribution item with another object. Two action
     * contribution items are equal if they refer to the identical Action.
     */
    @Override
    public boolean equals(Object o) {
        if (!(o instanceof ActionContributionItem)) {
            return false;
        }
        return action.equals(((ActionContributionItem) o).action);
    }

    /**
     * The <code>ActionContributionItem</code> implementation of this
     * <code>IContributionItem</code> method creates an SWT
     * <code>Button</code> for the action using the action's style. If the
     * action's checked property has been set, the button is created and primed
     * to the value of the checked property.
     */
    @Override
    public void fill(Composite parent) {
        if (widget != null || parent == null) {
            return;
        }

        int flags = SWT.PUSH;
        if (action != null) {
            if (action.getStyle() == IAction.AS_CHECK_BOX) {
                flags = SWT.TOGGLE;
            }
            if (action.getStyle() == IAction.AS_RADIO_BUTTON) {
                flags = SWT.RADIO;
            }
        }

        Button b = new Button(parent, flags);
        b.setData(this);
        b.addListener(SWT.Dispose, getButtonListener());
        // Don't hook a dispose listener on the parent
        b.addListener(SWT.Selection, getButtonListener());
        if (action.getHelpListener() != null) {
            b.addHelpListener(action.getHelpListener());
        }
        widget = b;

        update(null);

        // Attach some extra listeners.
        action.addPropertyChangeListener(propertyListener);
        if (action != null) {
            String commandId = action.getActionDefinitionId();
            ExternalActionManager.ICallback callback = ExternalActionManager.getInstance().getCallback();

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

    /**
     * The <code>ActionContributionItem</code> implementation of this
     * <code>IContributionItem</code> method creates an SWT
     * <code>MenuItem</code> for the action using the action's style. If the
     * action's checked property has been set, a button is created and primed to
     * the value of the checked property. If the action's menu creator property
     * has been set, a cascading submenu is created.
     */
    @Override
    public void fill(Menu parent, int index) {
        if (widget != null || parent == null) {
            return;
        }

        int flags = SWT.PUSH;
        if (action != null) {
            int style = action.getStyle();
            switch (style) {
            case IAction.AS_CHECK_BOX:
                flags = SWT.CHECK;
                break;
            case IAction.AS_RADIO_BUTTON:
                flags = SWT.RADIO;
                break;
            case IAction.AS_DROP_DOWN_MENU:
                flags = SWT.CASCADE;
                break;
            default:
                break;
            }
        }

        MenuItem mi = null;
        if (index >= 0) {
            mi = new MenuItem(parent, flags, index);
        } else {
            mi = new MenuItem(parent, flags);
        }
        widget = mi;

        mi.setData(this);
        mi.addListener(SWT.Dispose, getMenuItemListener());
        mi.addListener(SWT.Selection, getMenuItemListener());
        if (action.getHelpListener() != null) {
            mi.addHelpListener(action.getHelpListener());
        }

        if (flags == SWT.CASCADE) {
            // just create a proxy for now, if the user shows it then
            // fill it in
            Menu subMenu = new Menu(parent);
            subMenu.addListener(SWT.Show, getMenuCreatorListener());
            subMenu.addListener(SWT.Hide, getMenuCreatorListener());
            mi.setMenu(subMenu);
        }

        update(null);

        // Attach some extra listeners.
        action.addPropertyChangeListener(propertyListener);
        if (action != null) {
            String commandId = action.getActionDefinitionId();
            ExternalActionManager.ICallback callback = ExternalActionManager.getInstance().getCallback();

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

    /**
     * The <code>ActionContributionItem</code> implementation of this ,
     * <code>IContributionItem</code> method creates an SWT
     * <code>ToolItem</code> for the action using the action's style. If the
     * action's checked property has been set, a button is created and primed to
     * the value of the checked property. If the action's menu creator property
     * has been set, a drop-down tool item is created.
     */
    @Override
    public void fill(ToolBar parent, int index) {
        if (widget != null || parent == null) {
            return;
        }

        int flags = SWT.PUSH;
        if (action != null) {
            int style = action.getStyle();
            switch (style) {
            case IAction.AS_CHECK_BOX:
                flags = SWT.CHECK;
                break;
            case IAction.AS_RADIO_BUTTON:
                flags = SWT.RADIO;
                break;
            case IAction.AS_DROP_DOWN_MENU:
                flags = SWT.DROP_DOWN;
                break;
            default:
                break;
            }
        }

        ToolItem ti = null;
        if (index >= 0) {
            ti = new ToolItem(parent, flags, index);
        } else {
            ti = new ToolItem(parent, flags);
        }
        ti.setData(this);
        ti.addListener(SWT.Selection, getToolItemListener());
        ti.addListener(SWT.Dispose, getToolItemListener());

        widget = ti;

        update(null);

        // Attach some extra listeners.
        action.addPropertyChangeListener(propertyListener);
        if (action != null) {
            String commandId = action.getActionDefinitionId();
            ExternalActionManager.ICallback callback = ExternalActionManager.getInstance().getCallback();

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

    /**
     * Returns the action associated with this contribution item.
     *
     * @return the action
     */
    public IAction getAction() {
        return action;
    }

    /**
     * Returns the listener for SWT button widget events.
     *
     * @return a listener for button events
     */
    private Listener getButtonListener() {
        if (buttonListener == null) {
            buttonListener = 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 = 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 = 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) {
            return; // Not for us.
        }
        // Dispose of the menu creator.
        if (action.getStyle() == IAction.AS_DROP_DOWN_MENU && menuCreatorCalled) {
            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 || item != widget) {
            return; // Not for us
        }
        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 == SWT.ARROW) { // on drop-down button
                if (action.getStyle() == IAction.AS_DROP_DOWN_MENU) {
                    IMenuCreator mc = action.getMenuCreator();
                    menuCreatorCalled = true;
                    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
                            Point point = ti.getParent().toDisplay(new Point(e.x, e.y));
                            m.setLocation(point.x, point.y); // waiting
                            // for SWT
                            // 0.42
                            m.setVisible(true);
                            return; // we don't fire the action
                        }
                    }
                }
            }
        }

        ExternalActionManager.IExecuteCallback callback = null;
        String actionDefinitionId = action.getActionDefinitionId();
        if (actionDefinitionId != null) {
            Object obj = ExternalActionManager.getInstance().getCallback();
            if (obj instanceof ExternalActionManager.IExecuteCallback) {
                callback = (ExternalActionManager.IExecuteCallback) obj;
            }
        }

        // 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 = 0L;
            if (trace) {
                ms = System.currentTimeMillis();
                System.out.println("Running action: " + action.getText()); //$NON-NLS-1$
            }

            IPropertyChangeListener resultListener = null;
            if (callback != null) {
                resultListener = event -> {
                    // Check on result
                    if (event.getProperty().equals(IAction.RESULT)) {
                        if (event.getNewValue() instanceof Boolean) {
                            result = (Boolean) event.getNewValue();
                        }
                    }
                };
                action.addPropertyChangeListener(resultListener);
                callback.preExecute(action, e);
            }

            action.runWithEvent(e);

            if (callback != null) {
                if (result == null || result.equals(Boolean.TRUE)) {
                    callback.postExecuteSuccess(action, Boolean.TRUE);
                } else {
                    callback.postExecuteFailure(action,
                            new ExecutionException(action.getText() + " returned failure.")); //$NON-NLS-1$
                }
            }

            if (resultListener != null) {
                result = null;
                action.removePropertyChangeListener(resultListener);
            }
            if (trace) {
                System.out.println((System.currentTimeMillis() - ms) + " ms to run action: " + action.getText()); //$NON-NLS-1$
            }
        } else {
            if (callback != null) {
                callback.notEnabled(action, new NotEnabledException(action.getText() + " is not enabled.")); //$NON-NLS-1$
            }
        }
    }

    @Override
    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.
     */
    @Override
    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;
    }

    @Override
    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.
     */
    @Override
    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>.
     */
    @Override
    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
     */
    @Override
    public void update(String propertyName) {
        if (widget == null) {
            return;
        }

        // 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) {
            updateToolItem((ToolItem) widget, textChanged, imageChanged, tooltipTextChanged, enableStateChanged,
                    checkChanged);
        } else if (widget instanceof MenuItem) {
            updateMenuItem((MenuItem) widget, textChanged, imageChanged, tooltipTextChanged, enableStateChanged,
                    checkChanged);
        } else if (widget instanceof Button) {
            updateButton((Button) widget, textChanged, imageChanged, tooltipTextChanged, enableStateChanged,
                    checkChanged);
        }
    }

    private void updateToolItem(ToolItem ti, boolean textChanged, boolean imageChanged, boolean tooltipTextChanged,
            boolean enableStateChanged, boolean checkChanged) {
        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);
            }
        }

        if (imageChanged) {
            // Only substitute a missing image if it has no text.
            updateImages(!showText);
        }

        if (tooltipTextChanged || textChanged) {
            String toolTip = action.getToolTipText();
            if ((toolTip == null) || (toolTip.length() == 0)) {
                toolTip = text;
            }

            ExternalActionManager.ICallback callback = ExternalActionManager.getInstance().getCallback();
            String commandId = action.getActionDefinitionId();
            if ((callback != null) && (commandId != null) && (toolTip != null)) {
                String acceleratorText = callback.getAcceleratorText(commandId);
                if (acceleratorText != null && acceleratorText.length() != 0) {
                    toolTip = JFaceResources.format("Toolbar_Tooltip_Accelerator", //$NON-NLS-1$
                            toolTip, acceleratorText);
                }
            }

            // If the text is showing, then only set the tooltip if different.
            if (!showText || toolTip != null && !toolTip.equals(text)) {
                ti.setToolTipText(toolTip);
            } else {
                ti.setToolTipText(null);
            }
        }

        if (enableStateChanged) {
            boolean shouldBeEnabled = action.isEnabled() && isEnabledAllowed();

            if (ti.getEnabled() != shouldBeEnabled) {
                ti.setEnabled(shouldBeEnabled);
            }
        }

        if (checkChanged) {
            boolean bv = action.isChecked();

            if (ti.getSelection() != bv) {
                ti.setSelection(bv);
            }
        }
    }

    private void updateMenuItemText(MenuItem mi) {
        int accelerator = 0;
        String acceleratorText = null;
        IAction updatedAction = getAction();
        String text = null;
        accelerator = updatedAction.getAccelerator();
        ExternalActionManager.ICallback callback = ExternalActionManager.getInstance().getCallback();

        // Block accelerators that are already in use.
        if ((accelerator != 0) && (callback != null) && (callback.isAcceleratorInUse(accelerator))) {
            accelerator = 0;
        }

        /*
         * Process accelerators on GTK in a special way to avoid Bug 42009. We will
         * override the native input method by allowing these reserved accelerators to
         * be placed on the menu. We will only do this for "Ctrl+Shift+[0-9A-FU]".
         */
        final String commandId = updatedAction.getActionDefinitionId();
        if ((Util.isGtk()) && (callback instanceof IBindingManagerCallback) && (commandId != null)) {
            final IBindingManagerCallback bindingManagerCallback = (IBindingManagerCallback) callback;
            final IKeyLookup lookup = KeyLookupFactory.getDefault();
            final TriggerSequence[] triggerSequences = bindingManagerCallback.getActiveBindingsFor(commandId);
            for (final TriggerSequence triggerSequence : triggerSequences) {
                final Trigger[] triggers = triggerSequence.getTriggers();
                if (triggers.length == 1) {
                    final Trigger trigger = triggers[0];
                    if (trigger instanceof KeyStroke) {
                        final KeyStroke currentKeyStroke = (KeyStroke) trigger;
                        final int currentNaturalKey = currentKeyStroke.getNaturalKey();
                        if ((currentKeyStroke.getModifierKeys() == (lookup.getCtrl() | lookup.getShift()))
                                && ((currentNaturalKey >= '0' && currentNaturalKey <= '9')
                                        || (currentNaturalKey >= 'A' && currentNaturalKey <= 'F')
                                        || (currentNaturalKey == 'U'))) {
                            accelerator = currentKeyStroke.getModifierKeys() | currentNaturalKey;
                            acceleratorText = triggerSequence.format();
                            break;
                        }
                    }
                }
            }
        }

        if (accelerator == 0) {
            if ((callback != null) && (commandId != null)) {
                acceleratorText = callback.getAcceleratorText(commandId);
            }
        }

        IContributionManagerOverrides overrides = null;

        if (getParent() != null) {
            overrides = getParent().getOverrides();
        }

        if (overrides != null) {
            text = getParent().getOverrides().getText(this);
        }

        mi.setAccelerator(accelerator);

        if (text == null) {
            text = updatedAction.getText();
        }

        if (text != null && acceleratorText == null) {
            // Use extracted accelerator text in case accelerator cannot be fully
            // represented in one int (e.g. multi-stroke keys).
            acceleratorText = LegacyActionTools.extractAcceleratorText(text);
            if (acceleratorText == null && accelerator != 0) {
                acceleratorText = Action.convertAccelerator(accelerator);
            }
        }

        if (text == null) {
            text = ""; //$NON-NLS-1$
        } else {
            text = Action.removeAcceleratorText(text);
        }

        if (acceleratorText == null) {
            mi.setText(text);
        } else {
            mi.setText(text + '\t' + acceleratorText);
        }
    }

    private void updateMenuItem(MenuItem mi, boolean textChanged, boolean imageChanged, boolean tooltipTextChanged,
            boolean enableStateChanged, boolean checkChanged) {
        if (textChanged) {
            updateMenuItemText(mi);
        }

        if (tooltipTextChanged) {
            mi.setToolTipText(action.getToolTipText());
        }

        if (imageChanged) {
            updateImages(false);
        }

        if (enableStateChanged) {
            boolean shouldBeEnabled = action.isEnabled() && isEnabledAllowed();

            if (mi.getEnabled() != shouldBeEnabled) {
                mi.setEnabled(shouldBeEnabled);
            }
        }

        if (checkChanged) {
            boolean bv = action.isChecked();

            if (mi.getSelection() != bv) {
                mi.setSelection(bv);
            }
        }
    }

    private void updateButton(Button button, boolean textChanged, boolean imageChanged, boolean tooltipTextChanged,
            boolean enableStateChanged, boolean checkChanged) {
        if (imageChanged) {
            updateImages(false);
        }

        if (textChanged) {
            String text = action.getText();
            boolean showText = text != null && ((getMode() & MODE_FORCE_TEXT) != 0 || !hasImages(action));
            // Only do the trimming if the text will be used.
            if (showText) {
                text = Action.removeAcceleratorText(text);
            }
            String textToSet = showText ? text : ""; //$NON-NLS-1$
            button.setText(textToSet);
        }

        if (tooltipTextChanged) {
            button.setToolTipText(action.getToolTipText());
        }

        if (enableStateChanged) {
            boolean shouldBeEnabled = action.isEnabled() && isEnabledAllowed();

            if (button.getEnabled() != shouldBeEnabled) {
                button.setEnabled(shouldBeEnabled);
            }
        }

        if (checkChanged) {
            boolean bv = action.isChecked();

            if (button.getSelection() != bv) {
                button.setSelection(bv);
            }
        }
    }

    /**
     * Updates the images for this action.
     *
     * @param forceImage
     *            <code>true</code> if some form of image is compulsory, and
     *            <code>false</code> if it is acceptable for this item to have
     *            no image
     * @return <code>true</code> if there are images for this action,
     *         <code>false</code> if not
     */
    private boolean updateImages(boolean forceImage) {

        ResourceManager parentResourceManager = JFaceResources.getResources();

        if (widget instanceof ToolItem) {
            if (USE_COLOR_ICONS) {
                ImageDescriptor image = action.getHoverImageDescriptor();
                if (image == null) {
                    image = action.getImageDescriptor();
                }
                ImageDescriptor disabledImage = action.getDisabledImageDescriptor();

                // Make sure there is a valid image.
                if (image == null && forceImage) {
                    image = ImageDescriptor.getMissingImageDescriptor();
                }

                LocalResourceManager localManager = new LocalResourceManager(parentResourceManager);

                // performance: more efficient in SWT to set disabled and hot
                // image before regular image
                ((ToolItem) widget).setDisabledImage(
                        disabledImage == null ? null : localManager.createImageWithDefault(disabledImage));
                ((ToolItem) widget).setImage(image == null ? null : localManager.createImageWithDefault(image));

                disposeOldImages();
                imageManager = localManager;

                return image != null;
            }
            ImageDescriptor image = action.getImageDescriptor();
            ImageDescriptor hoverImage = action.getHoverImageDescriptor();
            ImageDescriptor disabledImage = action.getDisabledImageDescriptor();

            // If there is no regular image, but there is a hover image,
            // convert the hover image to gray and use it as the regular image.
            if (image == null && hoverImage != null) {
                image = ImageDescriptor.createWithFlags(action.getHoverImageDescriptor(), SWT.IMAGE_GRAY);
            } else {
                // If there is no hover image, use the regular image as the
                // hover image,
                // and convert the regular image to gray
                if (hoverImage == null && image != null) {
                    hoverImage = image;
                    image = ImageDescriptor.createWithFlags(action.getImageDescriptor(), SWT.IMAGE_GRAY);
                }
            }

            // Make sure there is a valid image.
            if (hoverImage == null && image == null && forceImage) {
                image = ImageDescriptor.getMissingImageDescriptor();
            }

            // Create a local resource manager to remember the images we've
            // allocated for this tool item
            LocalResourceManager localManager = new LocalResourceManager(parentResourceManager);

            // performance: more efficient in SWT to set disabled and hot image
            // before regular image
            ((ToolItem) widget).setDisabledImage(
                    disabledImage == null ? null : localManager.createImageWithDefault(disabledImage));
            ((ToolItem) widget)
                    .setHotImage(hoverImage == null ? null : localManager.createImageWithDefault(hoverImage));
            ((ToolItem) widget).setImage(image == null ? null : localManager.createImageWithDefault(image));

            // Now that we're no longer referencing the old images, clear them
            // out.
            disposeOldImages();
            imageManager = localManager;

            return image != null;
        } else if (widget instanceof Item || widget instanceof Button) {

            // Use hover image if there is one, otherwise use regular image.
            ImageDescriptor image = action.getHoverImageDescriptor();
            if (image == null) {
                image = action.getImageDescriptor();
            }
            // Make sure there is a valid image.
            if (image == null && forceImage) {
                image = ImageDescriptor.getMissingImageDescriptor();
            }

            // Create a local resource manager to remember the images we've
            // allocated for this widget
            LocalResourceManager localManager = new LocalResourceManager(parentResourceManager);

            if (widget instanceof Item) {
                ((Item) widget).setImage(image == null ? null : localManager.createImageWithDefault(image));
            } else if (widget instanceof Button) {
                ((Button) widget).setImage(image == null ? null : localManager.createImageWithDefault(image));
            }

            // Now that we're no longer referencing the old images, clear them
            // out.
            disposeOldImages();
            imageManager = localManager;

            return image != null;
        }
        return false;
    }

    /**
     * Dispose any images allocated for this contribution item
     */
    private void disposeOldImages() {
        if (imageManager != null) {
            imageManager.dispose();
            imageManager = null;
        }
    }

    /**
     * Shorten the given text <code>t</code> so that its length doesn't exceed
     * the width of the given ToolItem.The default implementation replaces
     * characters in the center of the original string with an ellipsis ("...").
     * Override if you need a different strategy.
     *
     * @param textValue
     *            the text to shorten
     * @param item
     *            the tool item the text belongs to
     * @return the shortened string
     *
     */
    protected String shortenText(String textValue, ToolItem item) {
        if (textValue == null) {
            return null;
        }

        GC gc = new GC(item.getParent());

        int maxWidth = item.getImage().getBounds().width * 4;

        if (gc.textExtent(textValue).x < maxWidth) {
            gc.dispose();
            return textValue;
        }

        for (int i = textValue.length(); i > 0; i--) {
            String test = textValue.substring(0, i);
            test = test + ellipsis;
            if (gc.textExtent(test).x < maxWidth) {
                gc.dispose();
                return test;
            }

        }
        gc.dispose();
        // If for some reason we fall through abort
        return textValue;
    }

    @Override
    public void dispose() {
        if (widget != null) {
            widget.dispose();
            widget = null;
        }
        holdMenu = null;
    }

    /**
     * Handle show and hide on the proxy menu for IAction.AS_DROP_DOWN_MENU
     * actions.
     *
     * @return the appropriate listener
     * @since 3.4
     */
    private Listener getMenuCreatorListener() {
        if (menuCreatorListener == null) {
            menuCreatorListener = event -> {
                switch (event.type) {
                case SWT.Show:
                    handleShowProxy((Menu) event.widget);
                    break;
                case SWT.Hide:
                    handleHideProxy((Menu) event.widget);
                    break;
                }
            };
        }
        return menuCreatorListener;
    }

    /**
     * This is the easiest way to hold the menu until we can swap it in to the
     * proxy.
     */
    private Menu holdMenu = null;

    private boolean menuCreatorCalled = false;

    /**
     * The proxy menu is being shown, we better get the real menu.
     *
     * @param proxy
     *            the proxy menu
     * @since 3.4
     */
    private void handleShowProxy(Menu proxy) {
        proxy.removeListener(SWT.Show, getMenuCreatorListener());
        IMenuCreator mc = action.getMenuCreator();
        menuCreatorCalled = true;
        if (mc == null) {
            return;
        }
        holdMenu = mc.getMenu(proxy.getParentMenu());
        if (holdMenu == null) {
            return;
        }
        copyMenu(holdMenu, proxy);
    }

    /**
     * Create MenuItems in the proxy menu that can execute the real menu items
     * if selected. Create proxy menus for any real item submenus.
     *
     * @param realMenu
     *            the real menu to copy from
     * @param proxy
     *            the proxy menu to populate
     * @since 3.4
     */
    private void copyMenu(Menu realMenu, Menu proxy) {
        if (realMenu.isDisposed() || proxy.isDisposed()) {
            return;
        }

        // we notify the real menu so it can populate itself if it was
        // listening for SWT.Show
        realMenu.notifyListeners(SWT.Show, null);

        final Listener passThrough = event -> {
            if (!event.widget.isDisposed()) {
                Widget realItem = (Widget) event.widget.getData();
                if (!realItem.isDisposed()) {
                    int style = event.widget.getStyle();
                    if (event.type == SWT.Selection && ((style & (SWT.TOGGLE | SWT.CHECK | SWT.RADIO)) != 0)
                            && realItem instanceof MenuItem) {
                        ((MenuItem) realItem).setSelection(((MenuItem) event.widget).getSelection());
                    }
                    event.widget = realItem;
                    realItem.notifyListeners(event.type, event);
                }
            }
        };

        MenuItem[] items = realMenu.getItems();
        for (final MenuItem realItem : items) {
            final MenuItem proxyItem = new MenuItem(proxy, realItem.getStyle());
            proxyItem.setData(realItem);
            proxyItem.setAccelerator(realItem.getAccelerator());
            proxyItem.setEnabled(realItem.getEnabled());
            proxyItem.setImage(realItem.getImage());
            proxyItem.setSelection(realItem.getSelection());
            proxyItem.setText(realItem.getText());

            // pass through any events
            proxyItem.addListener(SWT.Selection, passThrough);
            proxyItem.addListener(SWT.Arm, passThrough);
            proxyItem.addListener(SWT.Help, passThrough);

            final Menu itemMenu = realItem.getMenu();
            if (itemMenu != null) {
                // create a proxy for any sub menu items
                final Menu subMenu = new Menu(proxy);
                subMenu.setData(itemMenu);
                proxyItem.setMenu(subMenu);
                subMenu.addListener(SWT.Show, new Listener() {
                    @Override
                    public void handleEvent(Event event) {
                        event.widget.removeListener(SWT.Show, this);
                        if (event.type == SWT.Show) {
                            copyMenu(itemMenu, subMenu);
                        }
                    }
                });
                subMenu.addListener(SWT.Help, passThrough);
                subMenu.addListener(SWT.Hide, passThrough);
            }
        }
    }

    /**
     * The proxy menu is being hidden, so we need to make it go away.
     *
     * @param proxy
     *            the proxy menu
     * @since 3.4
     */
    private void handleHideProxy(final Menu proxy) {
        proxy.removeListener(SWT.Hide, getMenuCreatorListener());
        proxy.getDisplay().asyncExec(() -> {
            if (!proxy.isDisposed()) {
                MenuItem parentItem = proxy.getParentItem();
                proxy.dispose();
                parentItem.setMenu(holdMenu);
            }
            if (holdMenu != null && !holdMenu.isDisposed()) {
                holdMenu.notifyListeners(SWT.Hide, null);
            }
            holdMenu = null;
        });
    }

    /**
     * Return the widget associated with this contribution item. It should not
     * be cached, as it can be disposed and re-created by its containing
     * ContributionManager, which controls all of the widgets lifecycle methods.
     * <p>
     * This can be used to set layout data on the widget if appropriate. The
     * actual type of the widget can be any valid control for this
     * ContributionItem's current ContributionManager.
     * </p>
     *
     * @return the widget, or <code>null</code> depending on the lifecycle.
     * @since 3.4
     */
    public Widget getWidget() {
        return widget;
    }
}