| /****************************************************************************** |
| * Copyright (c) 2002, 2003 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.runtime.common.ui.services.internal.icon; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.eclipse.core.runtime.IAdaptable; |
| import org.eclipse.core.runtime.IConfigurationElement; |
| |
| import org.eclipse.gmf.runtime.common.core.service.AbstractProviderConfiguration; |
| |
| /** |
| * A provider configuration for the <code>IconService</code>. It helps in filtering out |
| * and delay loading unrelated providers. |
| * |
| * @author chmahone |
| */ |
| public class IconServiceProviderConfiguration extends AbstractProviderConfiguration { |
| |
| /** constants corresponding to different symbols in the extention schema */ |
| private static final String CONTEXT = "context"; //$NON-NLS-1$ |
| private static final String ELEMENTS = "elements"; //$NON-NLS-1$ |
| |
| /** a map of requests supported by this provider to their target contexts*/ |
| private List requests = new ArrayList(); |
| |
| /** |
| * Builds a new provider contribution descriptor by parsing its configuration element |
| * |
| * @param configElement A provider configuration element |
| * @return A provider XML contribution descriptor |
| */ |
| public static IconServiceProviderConfiguration parse(IConfigurationElement configElement) { |
| assert null != configElement : "null provider configuration element"; //$NON-NLS-1$ |
| return new IconServiceProviderConfiguration(configElement); |
| } |
| |
| /** |
| * Creates a new <code>ProviderContributionDescriptor</code> instance |
| * given a provider configuration element |
| * |
| * @param configElement The provider XML configuration element |
| */ |
| private IconServiceProviderConfiguration(IConfigurationElement configElement) { |
| IConfigurationElement configChildren[]; |
| |
| // read the object descriptors |
| Map objects = new HashMap(); |
| configChildren = configElement.getChildren(OBJECT); |
| for (int i = 0; i < configChildren.length; i++) { |
| String id = configChildren[i].getAttribute(ID); |
| if (id != null) |
| objects.put(id, new ObjectDescriptor(configChildren[i])); |
| } |
| |
| // read the context descriptors |
| configChildren = configElement.getChildren(CONTEXT); |
| for (int i = 0; i < configChildren.length; i++) { |
| List elements = |
| getObjectList( |
| configChildren[i].getAttribute(ELEMENTS), |
| objects, |
| configElement); |
| if (elements != null) |
| requests.add( |
| new ContextDescriptor(elements)); |
| } |
| } |
| |
| /** |
| * Determines if the provider understands the given context |
| * The provider understands the request if: |
| * 1- There are no listed provider contexts |
| * 2- The context matches one of the provider contexts |
| * |
| * @param elementAdapter adaptable to <code>IElement</code> |
| * @return boolean <code>true</code> if it supports; <code>false</code> otherwise |
| */ |
| public boolean supports(IAdaptable elementAdapter) { |
| if (requests.isEmpty()) |
| return true; |
| |
| Iterator iter = requests.iterator(); |
| while (iter.hasNext()) { |
| ContextDescriptor request = (ContextDescriptor) iter.next(); |
| if (request.matches(elementAdapter)) |
| return true; |
| } |
| return false; |
| } |
| |
| /** |
| * A descriptor for a provider context |
| */ |
| private static class ContextDescriptor { |
| /** the element adapters */ |
| private final List elementAdapters; |
| |
| /** |
| * creates a new context descriptor from its context info |
| * |
| * @param elementAdapters The element adapters |
| */ |
| public ContextDescriptor(List elementAdapters) { |
| this.elementAdapters = elementAdapters; |
| } |
| |
| /** |
| * Determines if the context descriptor matches the given context |
| * |
| * @param elementAdapter adaptable to <code>IElement</code> |
| * @return boolean |
| */ |
| public boolean matches(IAdaptable elementAdapter) { |
| return objectMatches(elementAdapter, elementAdapters); |
| } |
| } |
| |
| } |