| /****************************************************************************** |
| * Copyright (c) 2005 IBM Corporation 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: |
| * IBM Corporation - initial API and implementation |
| ****************************************************************************/ |
| |
| package org.eclipse.gmf.examples.runtime.common.service.application; |
| |
| import java.util.List; |
| |
| import org.eclipse.core.runtime.IConfigurationElement; |
| import org.eclipse.gmf.examples.runtime.common.service.ServicePlugin; |
| import org.eclipse.gmf.runtime.common.core.service.ExecutionStrategy; |
| import org.eclipse.gmf.runtime.common.core.service.IOperation; |
| import org.eclipse.gmf.runtime.common.core.service.Service; |
| |
| /** |
| * Widget Service class. Service which provides the creation of Widgets. |
| * |
| * @see org.eclipse.gmf.runtime.common.core.service |
| */ |
| public class WidgetService |
| extends Service |
| implements IWidgetProvider { |
| |
| /** |
| * The singleton instance of the WidgetService. |
| */ |
| private final static WidgetService service = new WidgetService(); |
| |
| static { |
| service.configureProviders(ServicePlugin.getPluginId(), "widgetProviders"); //$NON-NLS-1$ |
| } |
| |
| /** |
| * Retrieves the singleton instance of the WidgetService. |
| * |
| * @return The WidgetService service singleton. |
| */ |
| public static WidgetService getInstance() { |
| return service; |
| } |
| |
| /** |
| * Returns a <code>List</code> containing the Widgets requested or null if no Widget |
| * providers are found that can create orderSize Widgets. |
| * @see org.eclipse.gmf.examples.runtime.common.service.application.IWidgetProvider#createWidget(int) |
| */ |
| public Object createWidget(int orderSize) { |
| return execute(new CreateWidgetOperation(orderSize)); |
| } |
| |
| /** |
| * Executes the operation using a <code>ExecutingStrategy.FIRST</code> |
| * @param operation the operation to execute |
| * @return the results of the operation |
| */ |
| public Object execute(IOperation operation) { |
| List results = execute(ExecutionStrategy.FIRST, operation); |
| return results.isEmpty() ? null : results; |
| } |
| |
| /** |
| * Creates a new ProvderDescriptor based on the <code>IConfigurationElement</code>. |
| * @see org.eclipse.gmf.runtime.common.core.service.Service#newProviderDescriptor(org.eclipse.core.runtime.IConfigurationElement) |
| */ |
| protected Service.ProviderDescriptor newProviderDescriptor(IConfigurationElement element) { |
| return new WidgetProviderDescriptor(element); |
| } |
| |
| /** |
| * WidgetProviderDescriptor. Provides convenient access to |
| * WidgetProvider configuration information. |
| * |
| */ |
| protected static class WidgetProviderDescriptor |
| extends Service.ProviderDescriptor { |
| |
| /** the provider configuration parsed from XML */ |
| private WidgetServiceProviderConfiguration providerConfiguration; |
| |
| /** |
| * Constructs a <code>IWidgetProvider</code> descriptor for |
| * the specified configuration element. |
| * |
| * @param element The configuration element describing the provider. |
| */ |
| public WidgetProviderDescriptor(IConfigurationElement element) { |
| super(element); |
| |
| this.providerConfiguration = |
| WidgetServiceProviderConfiguration.parse(element); |
| assert null != element : "NULL configuration element"; //$NON-NLS-1$ |
| } |
| |
| /** |
| * Returns <code>true</code> if the given ProviderDescriptor |
| * @see org.eclipse.gmf.runtime.common.core.service.IProvider#provides(org.eclipse.gmf.runtime.common.core.service.IOperation) |
| */ |
| public boolean provides(IOperation operation) { |
| if (getPolicy() != null) |
| return getPolicy().provides(operation); |
| if (provider == null) { |
| if (isSupportedInExtention(operation)) { |
| providerConfiguration = null; |
| return getProvider().provides(operation); |
| } |
| return false; |
| } |
| return getProvider().provides(operation); |
| } |
| |
| /** |
| * Checks if the operation is supported by the XML extension |
| * @param operation |
| * @return |
| */ |
| private boolean isSupportedInExtention(IOperation operation) { |
| if (operation instanceof CreateWidgetOperation) { |
| return providerConfiguration.supports(((CreateWidgetOperation)operation).getOrderSize()); |
| } |
| return false; |
| } |
| } |
| } |