1 files changed, 140 insertions, 0 deletions
diff --git a/plugins/toolsmiths/validation/org.eclipse.papyrus.toolsmiths.validation.common/src/org/eclipse/papyrus/toolsmiths/validation/common/DelegatingURIConverterService.java b/plugins/toolsmiths/validation/org.eclipse.papyrus.toolsmiths.validation.common/src/org/eclipse/papyrus/toolsmiths/validation/common/DelegatingURIConverterService.java
new file mode 100644
index 00000000000..b45b1b21a35
--- /dev/null
+++ b/plugins/toolsmiths/validation/org.eclipse.papyrus.toolsmiths.validation.common/src/org/eclipse/papyrus/toolsmiths/validation/common/DelegatingURIConverterService.java
@@ -0,0 +1,140 @@
+/*****************************************************************************
+ * Copyright (c) 2021 Christian W. Damus, CEA LIST, and others.
+ *
+ * All rights reserved. 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
+ * http://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *   Christian W. Damus - Initial API and implementation
+ *
+ *****************************************************************************/
+
+package org.eclipse.papyrus.toolsmiths.validation.common;
+
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.function.Predicate;
+
+import org.eclipse.emf.common.util.URI;
+import org.eclipse.emf.ecore.resource.ResourceSet;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.ServiceReference;
+import org.osgi.util.tracker.ServiceTracker;
+import org.osgi.util.tracker.ServiceTrackerCustomizer;
+
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.Multimap;
+import com.google.common.collect.Multimaps;
+
+/**
+ * The delegating URI converter service implementation.
+ */
+class DelegatingURIConverterService implements URIConverterService {
+
+	private final Multimap<String, URIConverterService> delegates = Multimaps.synchronizedMultimap(ArrayListMultimap.create());
+	private ServiceTracker<URIConverterService, URIConverterService> delegatesTracker;
+
+	DelegatingURIConverterService() {
+		super();
+
+		BundleContext context = Activator.getDefault().getBundle().getBundleContext();
+		delegatesTracker = new ServiceTracker<>(context, URIConverterService.class, new Customizer(context));
+		delegatesTracker.open();
+	}
+
+	@Override
+	public URI normalize(URI uri, ResourceSet context) {
+		URI result = context.getURIConverter().normalize(uri);
+
+		Collection<URIConverterService> delegates = this.delegates.get(uri.scheme());
+		if (!delegates.isEmpty()) {
+			result = normalize(uri, context, delegates);
+		}
+
+		return result;
+	}
+
+	private URI normalize(URI uri, ResourceSet context, Collection<URIConverterService> delegates) {
+		URI result = uri;
+
+		for (Iterator<URIConverterService> iter = delegates.iterator(); iter.hasNext() && uri.equals(result);) {
+			result = iter.next().normalize(uri, context);
+		}
+
+		return result;
+	}
+
+	//
+	// Nested types
+	//
+
+	private final class Customizer implements ServiceTrackerCustomizer<URIConverterService, URIConverterService> {
+
+		private final BundleContext context;
+
+		Customizer(BundleContext context) {
+			super();
+
+			this.context = context;
+		}
+
+		@Override
+		public URIConverterService addingService(ServiceReference<URIConverterService> reference) {
+			return register(reference, context.getService(reference));
+		}
+
+		private URIConverterService register(ServiceReference<URIConverterService> reference, URIConverterService service) {
+			URIConverterService result = service;
+
+			Object schemes = reference.getProperty(SCHEME_PROPERTY);
+			if (schemes instanceof String) {
+				register((String) schemes, result);
+			} else if (schemes instanceof String[]) {
+				String[] schemeArray = (String[]) schemes;
+				if (schemeArray.length == 0) {
+					result = null;
+				} else {
+					for (String scheme : schemeArray) {
+						register(scheme, result);
+					}
+				}
+			}
+
+			if (result == null) {
+				context.ungetService(reference);
+			}
+
+			return result;
+		}
+
+		private void register(String scheme, URIConverterService service) {
+			if (service instanceof DelegatingURIConverterService) {
+				throw new IllegalArgumentException("attempt to register the delegating service to itself"); //$NON-NLS-1$
+			}
+
+			delegates.put(scheme, service);
+		}
+
+		private void unregister(URIConverterService service) {
+			delegates.values().removeIf(Predicate.isEqual(service));
+		}
+
+		@Override
+		public void modifiedService(ServiceReference<URIConverterService> reference, URIConverterService service) {
+			unregister(service);
+			register(reference, service);
+		}
+
+		@Override
+		public void removedService(ServiceReference<URIConverterService> reference, URIConverterService service) {
+			unregister(service);
+			context.ungetService(reference);
+		}
+
+	}
+
+}