1 files changed, 159 insertions, 0 deletions
diff --git a/plugins/org.eclipse.emf.compare.rcp.ui/src/org/eclipse/emf/compare/rcp/ui/internal/contentmergeviewer/customization/ContentMergeViewerCustomizationRegistry.java b/plugins/org.eclipse.emf.compare.rcp.ui/src/org/eclipse/emf/compare/rcp/ui/internal/contentmergeviewer/customization/ContentMergeViewerCustomizationRegistry.java
new file mode 100644
index 000000000..1ae18bbf0
--- /dev/null
+++ b/plugins/org.eclipse.emf.compare.rcp.ui/src/org/eclipse/emf/compare/rcp/ui/internal/contentmergeviewer/customization/ContentMergeViewerCustomizationRegistry.java
@@ -0,0 +1,159 @@
+/*******************************************************************************
+ * Copyright (c) 2016 EclipseSource Muenchen GmbH 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:
+ *     Stefan Dirix - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.emf.compare.rcp.ui.internal.contentmergeviewer.customization;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.eclipse.emf.compare.Comparison;
+import org.eclipse.emf.compare.adapterfactory.context.IContextTester;
+import org.eclipse.emf.compare.rcp.ui.mergeviewer.item.provider.IMergeViewerItemContentProvider;
+import org.eclipse.emf.compare.rcp.ui.mergeviewer.item.provider.IMergeViewerItemProvider;
+import org.eclipse.emf.compare.rcp.ui.mergeviewer.item.provider.IOptionalProvider;
+
+/**
+ * The registry responsible for managing the content merge viewer customizations.
+ * 
+ * @author Stefan Dirix <sdirix@eclipsesource.com>
+ */
+public class ContentMergeViewerCustomizationRegistry {
+	/** Keeps track of the extensions providing {@link IMergeViewerItemProvider}s. */
+	private final Map<String, ContentMergeViewerCustomizationDescriptor<IMergeViewerItemProvider>> registeredDescriptors;
+
+	/** Keeps track of the extensions providing {@link IMergeViewerItemContentProvider}s. */
+	private final Map<String, ContentMergeViewerCustomizationDescriptor<IMergeViewerItemContentProvider>> registeredTreeDescriptors;
+
+	/**
+	 * Constructs and initialized this registry.
+	 */
+	public ContentMergeViewerCustomizationRegistry() {
+		registeredDescriptors = new LinkedHashMap<String, ContentMergeViewerCustomizationDescriptor<IMergeViewerItemProvider>>();
+		registeredTreeDescriptors = new LinkedHashMap<String, ContentMergeViewerCustomizationDescriptor<IMergeViewerItemContentProvider>>();
+	}
+
+	/**
+	 * Adds the given {@link ContentMergeViewerCustomizationDescriptor} to this registry, using the given
+	 * {@code className} as the identifier.
+	 * 
+	 * @param className
+	 *            The identifier for the given {@link ContentMergeViewerCustomizationDescriptor}.
+	 * @param descriptor
+	 *            The {@link ContentMergeViewerCustomizationDescriptor} which is to be added to this registry.
+	 */
+	public void addCustomization(String className,
+			ContentMergeViewerCustomizationDescriptor<IMergeViewerItemProvider> descriptor) {
+		registeredDescriptors.put(className, descriptor);
+	}
+
+	/**
+	 * Adds the given {@link ContentMergeViewerCustomizationDescriptor} to this registry, using the given
+	 * {@code className} as the identifier.
+	 * 
+	 * @param className
+	 *            The identifier for the given {@link ContentMergeViewerCustomizationDescriptor}.
+	 * @param descriptor
+	 *            The {@link ContentMergeViewerCustomizationDescriptor} which is to be added to this registry.
+	 */
+	public void addTreeCustomization(String className,
+			ContentMergeViewerCustomizationDescriptor<IMergeViewerItemContentProvider> descriptor) {
+		registeredTreeDescriptors.put(className, descriptor);
+	}
+
+	/**
+	 * Removes the {@link ContentMergeViewerCustomizationDescriptor} and its managed
+	 * {@link IDependencyProvider} identified by the given {@code className} from this registry.
+	 * 
+	 * @param className
+	 *            Identifier of the provider we are to remove from this registry.
+	 */
+	public void removeDescriptor(String className) {
+		registeredDescriptors.remove(className);
+		registeredTreeDescriptors.remove(className);
+	}
+
+	/** Clears out all registered listeners from this registry. */
+	public void clear() {
+		registeredDescriptors.clear();
+		registeredTreeDescriptors.clear();
+	}
+
+	private <T extends IOptionalProvider> T getBestFittingProvider(
+			Collection<ContentMergeViewerCustomizationDescriptor<T>> descriptors, Comparison comparison,
+			Object object) {
+		ContentMergeViewerCustomizationDescriptor<T> bestDescriptor = null;
+		final Map<Object, Object> context = createContext(comparison);
+
+		for (ContentMergeViewerCustomizationDescriptor<T> descriptor : descriptors) {
+			IContextTester contextTester = descriptor.getContextTester();
+			// check context
+			if (contextTester != null && !contextTester.apply(context)) {
+				continue;
+			}
+			// check ranking
+			if (bestDescriptor != null && bestDescriptor.getRanking() > descriptor.getRanking()) {
+				continue;
+			}
+			// check provider
+			if (descriptor.getProvider().canHandle(object)) {
+				bestDescriptor = descriptor;
+			}
+		}
+
+		if (bestDescriptor != null) {
+			return bestDescriptor.getProvider();
+		}
+
+		return null;
+	}
+
+	/**
+	 * Creates the context for the {@link IContextTester}s.
+	 * 
+	 * @param comparison
+	 *            the {@link Comparison}.
+	 * @return the created context.
+	 */
+	private Map<Object, Object> createContext(Comparison comparison) {
+		final Map<Object, Object> context = new HashMap<Object, Object>();
+		context.put(IContextTester.CTX_COMPARISON, comparison);
+		return context;
+	}
+
+	/**
+	 * Returns the best fitting {@link IMergeViewerItemProvider}.
+	 * 
+	 * @param comparison
+	 *            the {@link Comparison} is used to check the context.
+	 * @param object
+	 *            the {@link Object} for which the {@link IMergeViewerItemProvider} is responsible.
+	 * @return the determined {@link IMergeViewerItemProvider} if one exists, {@code null} otherwise.
+	 */
+	public IMergeViewerItemProvider getBestFittingMergeViewerItemProvider(Comparison comparison,
+			Object object) {
+		return getBestFittingProvider(registeredDescriptors.values(), comparison, object);
+	}
+
+	/**
+	 * Returns the best fitting {@link IMergeViewerItemContentProvider}.
+	 * 
+	 * @param comparison
+	 *            the {@link Comparison} is used to check the context.
+	 * @param object
+	 *            the {@link Object} for which the {@link IMergeViewerItemContentProvider} is responsible.
+	 * @return the determined {@link IMergeViewerItemContentProvider} if one exists, {@code null} otherwise.
+	 */
+	public IMergeViewerItemContentProvider getBestFittingMergeViewerItemContentProvider(Comparison comparison,
+			Object object) {
+		return getBestFittingProvider(registeredTreeDescriptors.values(), comparison, object);
+	}
+}