bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/handlers/WidgetMethodHandler.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2018 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
  *     Bruno Haible haible@ilog.fr - bug 228890
  *******************************************************************************/
 package org.eclipse.ui.internal.handlers;

 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import org.eclipse.core.commands.AbstractHandler;
 import org.eclipse.core.commands.ExecutionEvent;
 import org.eclipse.core.commands.ExecutionException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExecutableExtension;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Listener;
 import org.eclipse.ui.internal.ExceptionHandler;

 /**
  * Handles the cut command in both dialogs and windows. This handler is enabled
  * if the focus control supports the "cut", "copy" or "paste" methods.
  *
  * @since 3.0
  */
 public class WidgetMethodHandler extends AbstractHandler implements IExecutableExtension {

 	/**
 	 * The parameters to pass to the method this handler invokes. This handler
 	 * always passes no parameters.
 	 */
 	public WidgetMethodHandler() {
 		display = Display.getCurrent();
 		if (display != null) {
 			focusListener = event -> updateEnablement();
 			display.addFilter(SWT.FocusIn, focusListener);
 		}
 	}

 	void updateEnablement() {
 		boolean rc = isHandled();
 		if (rc != isEnabled()) {
 			setBaseEnabled(rc);
 		}
 	}

 	/**
 	 * The name of the method to be invoked by this handler. This value should never
 	 * be <code>null</code>.
 	 */
 	protected String methodName;
 	private Listener focusListener;
 	private Display display;

 	@Override
 	public Object execute(final ExecutionEvent event) throws ExecutionException {
 		final Method methodToExecute = getMethodToExecute();
 		if (methodToExecute != null) {
 			try {
 				final Control focusControl = Display.getCurrent().getFocusControl();
 				if ((focusControl instanceof Composite)
 						&& ((((Composite) focusControl).getStyle() & SWT.EMBEDDED) != 0)) {
 					/*
 					 * Okay. Have a seat. Relax a while. This is going to be a bumpy ride. If it is
 					 * an embedded widget, then it *might* be a Swing widget. At the point where
 					 * this handler is executing, the key event is already bound to be swallowed. If
 					 * I don't do something, then the key will be gone for good. So, I will try to
 					 * forward the event to the Swing widget. Unfortunately, we can't even count on
 					 * the Swing libraries existing, so I need to use reflection everywhere. And, to
 					 * top it off, I need to dispatch the event on the Swing event queue, which
 					 * means that it will be carried out asynchronously to the SWT event queue.
 					 */
 					try {
 						final Object focusComponent = getFocusComponent();
 						if (focusComponent != null) {
 							Runnable methodRunnable = () -> {
 								try {
 									methodToExecute.invoke(focusComponent);
 								} catch (final IllegalAccessException e1) {
 									// The method is protected, so do
 									// nothing.
 								} catch (final InvocationTargetException e2) {
 									/*
 									 * I would like to log this exception -- and possibly show a dialog to the user
 									 * -- but I have to go back to the SWT event loop to do this. So, back we go....
 									 */
 									focusControl.getDisplay()
 											.asyncExec(() -> ExceptionHandler.getInstance()
 													.handleException(new ExecutionException(
 															"An exception occurred while executing " //$NON-NLS-1$
 																	+ methodToExecute.getName(),
 															e2.getTargetException())));
 								}
 							};

 							swingInvokeLater(methodRunnable);
 						}
 					} catch (final ClassNotFoundException e) {
 						// There is no Swing support, so do nothing.

 					} catch (final NoSuchMethodException e) {
 						// The API has changed, which seems amazingly unlikely.
 						throw new Error("Something is seriously wrong here"); //$NON-NLS-1$
 					}

 				} else {

 					methodToExecute.invoke(focusControl);
 				}

 			} catch (IllegalAccessException e) {
 				// The method is protected, so do nothing.

 			} catch (InvocationTargetException e) {
 				throw new ExecutionException("An exception occurred while executing " //$NON-NLS-1$
 						+ methodToExecute.getName(), e.getTargetException());

 			}
 		}

 		return null;
 	}

 	/**
 	 * Invoke a runnable on the swing EDT.
 	 *
 	 * @param methodRunnable
 	 * @throws ClassNotFoundException
 	 * @throws NoSuchMethodException
 	 * @throws IllegalAccessException
 	 * @throws InvocationTargetException
 	 */
 	protected void swingInvokeLater(Runnable methodRunnable)
 			throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {
 		final Class<?> swingUtilitiesClass = Class.forName("javax.swing.SwingUtilities"); //$NON-NLS-1$
 		final Method swingUtilitiesInvokeLaterMethod = swingUtilitiesClass.getMethod("invokeLater", //$NON-NLS-1$
 				Runnable.class);
 		swingUtilitiesInvokeLaterMethod.invoke(swingUtilitiesClass, methodRunnable);
 	}

 	/**
 	 * Find the swing focus component, if it is available.
 	 *
 	 * @return Hopefully, the swing focus component, but it can return
 	 *         <code>null</code>.
 	 * @throws ClassNotFoundException
 	 * @throws NoSuchMethodException
 	 * @throws IllegalAccessException
 	 * @throws InvocationTargetException
 	 */
 	protected Object getFocusComponent()
 			throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {
 		/*
 		 * Before JRE 1.4, one has to use
 		 * javax.swing.FocusManager.getCurrentManager().getFocusOwner(). Since JRE 1.4,
 		 * one has to use java.awt.KeyboardFocusManager.getCurrentKeyboardFocusManager
 		 * ().getFocusOwner(); the use of the older API would install a
 		 * LegacyGlueFocusTraversalPolicy which causes endless recursions in some
 		 * situations.
 		 */
 		Class<?> keyboardFocusManagerClass = null;
 		try {
 			keyboardFocusManagerClass = Class.forName("java.awt.KeyboardFocusManager"); //$NON-NLS-1$
 		} catch (ClassNotFoundException e) {
 			// switch to the old guy
 		}
 		if (keyboardFocusManagerClass != null) {
 			// Use JRE 1.4 API
 			final Method keyboardFocusManagerGetCurrentKeyboardFocusManagerMethod = keyboardFocusManagerClass
 					.getMethod("getCurrentKeyboardFocusManager"); //$NON-NLS-1$
 			final Object keyboardFocusManager = keyboardFocusManagerGetCurrentKeyboardFocusManagerMethod
 					.invoke(keyboardFocusManagerClass);
 			final Method keyboardFocusManagerGetFocusOwner = keyboardFocusManagerClass.getMethod("getFocusOwner"); //$NON-NLS-1$
 			return keyboardFocusManagerGetFocusOwner.invoke(keyboardFocusManager);
 		}
 		// Use JRE 1.3 API
 		final Class<?> focusManagerClass = Class.forName("javax.swing.FocusManager"); //$NON-NLS-1$
 		final Method focusManagerGetCurrentManagerMethod = focusManagerClass.getMethod("getCurrentManager"); //$NON-NLS-1$
 		final Object focusManager = focusManagerGetCurrentManagerMethod.invoke(focusManagerClass);
 		final Method focusManagerGetFocusOwner = focusManagerClass.getMethod("getFocusOwner"); //$NON-NLS-1$
 		return focusManagerGetFocusOwner.invoke(focusManager);

 	}

 	@Override
 	public final boolean isHandled() {
 		return getMethodToExecute() != null;
 	}

 	/**
 	 * Looks up the method on the focus control.
 	 *
 	 * @return The method on the focus control; <code>null</code> if none.
 	 */
 	protected Method getMethodToExecute() {
 		Display display = Display.getCurrent();
 		if (display == null)
 			return null;
 		final Control focusControl = display.getFocusControl();
 		Method method = null;

 		if (focusControl != null) {
 			final Class<?> clazz = focusControl.getClass();
 			try {
 				method = clazz.getMethod(methodName);
 			} catch (NoSuchMethodException e) {
 				// Fall through...
 			}
 		}

 		if ((method == null) && (focusControl instanceof Composite)
 				&& ((((Composite) focusControl).getStyle() & SWT.EMBEDDED) != 0)) {
 			/*
 			 * We couldn't find the appropriate method on the current focus control. It is
 			 * possible that the current focus control is an embedded SWT composite, which
 			 * could be containing some Swing components. If this is the case, then we
 			 * should try to pass through to the underlying Swing component hierarchy.
 			 * Insha'allah, this will work.
 			 */
 			try {
 				final Object focusComponent = getFocusComponent();
 				if (focusComponent != null) {
 					final Class<?> clazz = focusComponent.getClass();

 					try {
 						method = clazz.getMethod(methodName);
 					} catch (NoSuchMethodException e) {
 						// Do nothing.
 					}
 				}
 			} catch (final ClassNotFoundException e) {
 				// There is no Swing support, so do nothing.

 			} catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
 				// The API has changed, which seems amazingly unlikely.
 				throw new Error("Something is seriously wrong here"); //$NON-NLS-1$
 			}
 		}

 		return method;
 	}

 	@Override
 	public void setInitializationData(IConfigurationElement config, String propertyName, Object data) {
 		// The data is really just a string (i.e., the method name).
 		methodName = data.toString();
 	}

 	@Override
 	public void dispose() {
 		if (display != null && !display.isDisposed()) {
 			display.removeFilter(SWT.FocusIn, focusListener);
 		}
 		display = null;
 		focusListener = null;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2018 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
	* Bruno Haible haible@ilog.fr - bug 228890
	*******************************************************************************/
	package org.eclipse.ui.internal.handlers;

	import java.lang.reflect.InvocationTargetException;
	import java.lang.reflect.Method;
	import org.eclipse.core.commands.AbstractHandler;
	import org.eclipse.core.commands.ExecutionEvent;
	import org.eclipse.core.commands.ExecutionException;
	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.core.runtime.IExecutableExtension;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.swt.widgets.Listener;
	import org.eclipse.ui.internal.ExceptionHandler;

	/**
	* Handles the cut command in both dialogs and windows. This handler is enabled
	* if the focus control supports the "cut", "copy" or "paste" methods.
	*
	* @since 3.0
	*/
	public class WidgetMethodHandler extends AbstractHandler implements IExecutableExtension {

	/**
	* The parameters to pass to the method this handler invokes. This handler
	* always passes no parameters.
	*/
	public WidgetMethodHandler() {
	display = Display.getCurrent();
	if (display != null) {
	focusListener = event -> updateEnablement();
	display.addFilter(SWT.FocusIn, focusListener);
	}
	}

	void updateEnablement() {
	boolean rc = isHandled();
	if (rc != isEnabled()) {
	setBaseEnabled(rc);
	}
	}

	/**
	* The name of the method to be invoked by this handler. This value should never
	* be <code>null</code>.
	*/
	protected String methodName;
	private Listener focusListener;
	private Display display;

	@Override
	public Object execute(final ExecutionEvent event) throws ExecutionException {
	final Method methodToExecute = getMethodToExecute();
	if (methodToExecute != null) {
	try {
	final Control focusControl = Display.getCurrent().getFocusControl();
	if ((focusControl instanceof Composite)
	&& ((((Composite) focusControl).getStyle() & SWT.EMBEDDED) != 0)) {
	/*
	* Okay. Have a seat. Relax a while. This is going to be a bumpy ride. If it is
	* an embedded widget, then it might be a Swing widget. At the point where
	* this handler is executing, the key event is already bound to be swallowed. If
	* I don't do something, then the key will be gone for good. So, I will try to
	* forward the event to the Swing widget. Unfortunately, we can't even count on
	* the Swing libraries existing, so I need to use reflection everywhere. And, to
	* top it off, I need to dispatch the event on the Swing event queue, which
	* means that it will be carried out asynchronously to the SWT event queue.
	*/
	try {
	final Object focusComponent = getFocusComponent();
	if (focusComponent != null) {
	Runnable methodRunnable = () -> {
	try {
	methodToExecute.invoke(focusComponent);
	} catch (final IllegalAccessException e1) {
	// The method is protected, so do
	// nothing.
	} catch (final InvocationTargetException e2) {
	/*
	* I would like to log this exception -- and possibly show a dialog to the user
	* -- but I have to go back to the SWT event loop to do this. So, back we go....
	*/
	focusControl.getDisplay()
	.asyncExec(() -> ExceptionHandler.getInstance()
	.handleException(new ExecutionException(
	"An exception occurred while executing " //$NON-NLS-1$
	+ methodToExecute.getName(),
	e2.getTargetException())));
	}
	};

	swingInvokeLater(methodRunnable);
	}
	} catch (final ClassNotFoundException e) {
	// There is no Swing support, so do nothing.

	} catch (final NoSuchMethodException e) {
	// The API has changed, which seems amazingly unlikely.
	throw new Error("Something is seriously wrong here"); //$NON-NLS-1$
	}

	} else {

	methodToExecute.invoke(focusControl);
	}

	} catch (IllegalAccessException e) {
	// The method is protected, so do nothing.

	} catch (InvocationTargetException e) {
	throw new ExecutionException("An exception occurred while executing " //$NON-NLS-1$
	+ methodToExecute.getName(), e.getTargetException());

	}
	}

	return null;
	}

	/**
	* Invoke a runnable on the swing EDT.
	*
	* @param methodRunnable
	* @throws ClassNotFoundException
	* @throws NoSuchMethodException
	* @throws IllegalAccessException
	* @throws InvocationTargetException
	*/
	protected void swingInvokeLater(Runnable methodRunnable)
	throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {
	final Class<?> swingUtilitiesClass = Class.forName("javax.swing.SwingUtilities"); //$NON-NLS-1$
	final Method swingUtilitiesInvokeLaterMethod = swingUtilitiesClass.getMethod("invokeLater", //$NON-NLS-1$
	Runnable.class);
	swingUtilitiesInvokeLaterMethod.invoke(swingUtilitiesClass, methodRunnable);
	}

	/**
	* Find the swing focus component, if it is available.
	*
	* @return Hopefully, the swing focus component, but it can return
	* <code>null</code>.
	* @throws ClassNotFoundException
	* @throws NoSuchMethodException
	* @throws IllegalAccessException
	* @throws InvocationTargetException
	*/
	protected Object getFocusComponent()
	throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {
	/*
	* Before JRE 1.4, one has to use
	* javax.swing.FocusManager.getCurrentManager().getFocusOwner(). Since JRE 1.4,
	* one has to use java.awt.KeyboardFocusManager.getCurrentKeyboardFocusManager
	* ().getFocusOwner(); the use of the older API would install a
	* LegacyGlueFocusTraversalPolicy which causes endless recursions in some
	* situations.
	*/
	Class<?> keyboardFocusManagerClass = null;
	try {
	keyboardFocusManagerClass = Class.forName("java.awt.KeyboardFocusManager"); //$NON-NLS-1$
	} catch (ClassNotFoundException e) {
	// switch to the old guy
	}
	if (keyboardFocusManagerClass != null) {
	// Use JRE 1.4 API
	final Method keyboardFocusManagerGetCurrentKeyboardFocusManagerMethod = keyboardFocusManagerClass
	.getMethod("getCurrentKeyboardFocusManager"); //$NON-NLS-1$
	final Object keyboardFocusManager = keyboardFocusManagerGetCurrentKeyboardFocusManagerMethod
	.invoke(keyboardFocusManagerClass);
	final Method keyboardFocusManagerGetFocusOwner = keyboardFocusManagerClass.getMethod("getFocusOwner"); //$NON-NLS-1$
	return keyboardFocusManagerGetFocusOwner.invoke(keyboardFocusManager);
	}
	// Use JRE 1.3 API
	final Class<?> focusManagerClass = Class.forName("javax.swing.FocusManager"); //$NON-NLS-1$
	final Method focusManagerGetCurrentManagerMethod = focusManagerClass.getMethod("getCurrentManager"); //$NON-NLS-1$
	final Object focusManager = focusManagerGetCurrentManagerMethod.invoke(focusManagerClass);
	final Method focusManagerGetFocusOwner = focusManagerClass.getMethod("getFocusOwner"); //$NON-NLS-1$
	return focusManagerGetFocusOwner.invoke(focusManager);

	}

	@Override
	public final boolean isHandled() {
	return getMethodToExecute() != null;
	}

	/**
	* Looks up the method on the focus control.
	*
	* @return The method on the focus control; <code>null</code> if none.
	*/
	protected Method getMethodToExecute() {
	Display display = Display.getCurrent();
	if (display == null)
	return null;
	final Control focusControl = display.getFocusControl();
	Method method = null;

	if (focusControl != null) {
	final Class<?> clazz = focusControl.getClass();
	try {
	method = clazz.getMethod(methodName);
	} catch (NoSuchMethodException e) {
	// Fall through...
	}
	}

	if ((method == null) && (focusControl instanceof Composite)
	&& ((((Composite) focusControl).getStyle() & SWT.EMBEDDED) != 0)) {
	/*
	* We couldn't find the appropriate method on the current focus control. It is
	* possible that the current focus control is an embedded SWT composite, which
	* could be containing some Swing components. If this is the case, then we
	* should try to pass through to the underlying Swing component hierarchy.
	* Insha'allah, this will work.
	*/
	try {
	final Object focusComponent = getFocusComponent();
	if (focusComponent != null) {
	final Class<?> clazz = focusComponent.getClass();

	try {
	method = clazz.getMethod(methodName);
	} catch (NoSuchMethodException e) {
	// Do nothing.
	}
	}
	} catch (final ClassNotFoundException e) {
	// There is no Swing support, so do nothing.

	} catch (NoSuchMethodException \| IllegalAccessException \| InvocationTargetException e) {
	// The API has changed, which seems amazingly unlikely.
	throw new Error("Something is seriously wrong here"); //$NON-NLS-1$
	}
	}

	return method;
	}

	@Override
	public void setInitializationData(IConfigurationElement config, String propertyName, Object data) {
	// The data is really just a string (i.e., the method name).
	methodName = data.toString();
	}

	@Override
	public void dispose() {
	if (display != null && !display.isDisposed()) {
	display.removeFilter(SWT.FocusIn, focusListener);
	}
	display = null;
	focusListener = null;
	}
	}