1 files changed, 88 insertions, 0 deletions
diff --git a/plugins/infra/properties/org.eclipse.papyrus.infra.properties.edit/src/org/eclipse/papyrus/infra/properties/contexts/command/ContextDeleteCommand.java b/plugins/infra/properties/org.eclipse.papyrus.infra.properties.edit/src/org/eclipse/papyrus/infra/properties/contexts/command/ContextDeleteCommand.java
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index 00000000000..57ca90b97cf
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+++ b/plugins/infra/properties/org.eclipse.papyrus.infra.properties.edit/src/org/eclipse/papyrus/infra/properties/contexts/command/ContextDeleteCommand.java
@@ -0,0 +1,88 @@
+/*****************************************************************************
+ * 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.infra.properties.contexts.command;
+
+import java.util.Collection;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import org.eclipse.emf.common.command.Command;
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.emf.ecore.EStructuralFeature;
+import org.eclipse.emf.ecore.resource.Resource;
+import org.eclipse.emf.edit.command.DeleteCommand;
+import org.eclipse.emf.edit.domain.EditingDomain;
+import org.eclipse.papyrus.infra.properties.contexts.Context;
+import org.eclipse.papyrus.infra.properties.contexts.util.ContextUsageCrossReferencer;
+
+/**
+ * A specialized deletion command that restricts the scan for incoming references to only
+ * within loaded context resources.
+ *
+ * @since 4.1
+ */
+public class ContextDeleteCommand extends DeleteCommand {
+
+	/**
+	 * Initializes me with my contextual editing {@code domain} and a {@code collection} of objects to delete.
+	 *
+	 * @param domain
+	 *            the editing domain
+	 * @param collection
+	 *            objects to delete
+	 */
+	public ContextDeleteCommand(EditingDomain domain, Collection<?> collection) {
+		super(domain, collection);
+	}
+
+	@Override
+	protected Map<EObject, Collection<EStructuralFeature.Setting>> findReferences(Collection<EObject> eObjects) {
+		// Scope the search for cross-references to just the context resources, and excluding the XWT sections
+		Set<Resource> scope = domain.getResourceSet().getResources().stream()
+				.filter(this::isContextResource)
+				.collect(Collectors.toSet());
+
+		return new ContextUsageCrossReferencer(scope).findAllUsage(eObjects);
+	}
+
+	/**
+	 * Query whether a {@code resource} contains a Properties {@link Context}.
+	 *
+	 * @param resource
+	 *            a resource
+	 * @return whether it contains a context
+	 */
+	boolean isContextResource(Resource resource) {
+		return resource.isLoaded() && !resource.getContents().isEmpty()
+				&& resource.getContents().stream().anyMatch(Context.class::isInstance);
+	}
+
+	/**
+	 * Create a command to delete an {@code object}.
+	 */
+	public static Command create(EditingDomain domain, Object object) {
+		return create(domain, Set.of(object));
+	}
+
+	/**
+	 * Create a command to delete an {@code collection} of objects.
+	 */
+	public static Command create(EditingDomain domain, final Collection<?> collection) {
+		return new ContextDeleteCommand(domain, collection);
+	}
+
+}