| /* |
| * Copyright (c) 2013 Eike Stepper (Berlin, Germany) and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * Eike Stepper - initial API and implementation |
| * Christian W. Damus (CEA LIST) - bug 399306 - adapted from SafeActionDelegate |
| */ |
| package org.eclipse.net4j.util.ui.handlers; |
| |
| import org.eclipse.net4j.util.internal.ui.bundle.OM; |
| import org.eclipse.net4j.util.internal.ui.messages.Messages; |
| |
| import org.eclipse.core.commands.AbstractHandler; |
| import org.eclipse.core.commands.Command; |
| import org.eclipse.core.commands.ExecutionEvent; |
| import org.eclipse.core.commands.ExecutionException; |
| import org.eclipse.core.commands.common.NotDefinedException; |
| import org.eclipse.jface.dialogs.MessageDialog; |
| import org.eclipse.jface.viewers.ISelection; |
| import org.eclipse.jface.viewers.StructuredSelection; |
| import org.eclipse.ui.ISources; |
| import org.eclipse.ui.handlers.HandlerUtil; |
| |
| /** |
| * @author Eike Stepper |
| * @author Christian W. Damus (CEA LIST) |
| * |
| * @since 3.4 |
| */ |
| public abstract class SafeHandler extends AbstractHandler |
| { |
| private Command command; |
| |
| private ISelection selection; |
| |
| public SafeHandler() |
| { |
| } |
| |
| public Command getCommand() |
| { |
| return command; |
| } |
| |
| public ISelection getSelection() |
| { |
| return selection; |
| } |
| |
| public Object execute(ExecutionEvent event) throws ExecutionException |
| { |
| Object result = null; |
| |
| try |
| { |
| extractEventDetails(event); |
| |
| result = safeExecute(event); |
| } |
| catch (ExecutionException ex) |
| { |
| throw ex; |
| } |
| catch (Exception ex) |
| { |
| OM.LOG.error(ex); |
| MessageDialog.openError(null, getText(), |
| ex.getLocalizedMessage() + "\n" + Messages.getString("SafeActionDelegate_0")); //$NON-NLS-1$ //$NON-NLS-2$ |
| } |
| |
| return result; |
| } |
| |
| @Override |
| public void setEnabled(Object evaluationContext) |
| { |
| try |
| { |
| Object variable = HandlerUtil.getVariable(evaluationContext, ISources.ACTIVE_CURRENT_SELECTION_NAME); |
| selection = variable instanceof ISelection ? (ISelection)variable : StructuredSelection.EMPTY; |
| setBaseEnabled(updateSelection(selection)); |
| } |
| catch (Exception ex) |
| { |
| OM.LOG.error(ex); |
| } |
| } |
| |
| /** |
| * Extracts details from the {@code event} that we may need later, |
| * for example on a background thread when the original execution |
| * context is no longer valid. |
| */ |
| protected void extractEventDetails(ExecutionEvent event) |
| { |
| setEnabled(event.getApplicationContext()); |
| command = event.getCommand(); |
| } |
| |
| protected abstract Object safeExecute(ExecutionEvent event) throws Exception; |
| |
| protected String getText() |
| { |
| try |
| { |
| return command == null ? Messages.getString("SafeActionDelegate_1") : command.getName(); //$NON-NLS-1$ |
| } |
| catch (NotDefinedException e) |
| { |
| return Messages.getString("SafeActionDelegate_1"); //$NON-NLS-1$ |
| } |
| } |
| |
| protected boolean updateSelection(ISelection selection) |
| { |
| return true; |
| } |
| } |