1 files changed, 91 insertions, 0 deletions
diff --git a/plugins/infra/widget/org.eclipse.papyrus.infra.widgets/src/org/eclipse/papyrus/infra/widgets/creation/IAtomicOperationExecutor.java b/plugins/infra/widget/org.eclipse.papyrus.infra.widgets/src/org/eclipse/papyrus/infra/widgets/creation/IAtomicOperationExecutor.java
new file mode 100644
index 00000000000..dc69d248b2b
--- /dev/null
+++ b/plugins/infra/widget/org.eclipse.papyrus.infra.widgets/src/org/eclipse/papyrus/infra/widgets/creation/IAtomicOperationExecutor.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2014 CEA 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:
+ *   Christian W. Damus (CEA) - Initial API and implementation
+ *
+ */
+package org.eclipse.papyrus.infra.widgets.creation;
+
+import java.util.concurrent.Callable;
+
+import org.eclipse.core.runtime.OperationCanceledException;
+import org.eclipse.papyrus.infra.widgets.Activator;
+
+
+/**
+ * An interface that ensures execution of model changes as an atomic unit that is potentially undoable and redoable, such as on a "command stack"
+ * (whatever form it may take).
+ */
+public interface IAtomicOperationExecutor {
+
+	IAtomicOperationExecutor DEFAULT = new Default();
+
+	/**
+	 * Execute a runnable (an operation returning no result).
+	 * 
+	 * @param operation
+	 *        the operation to execute
+	 * @param label
+	 *        an optional label to associate with the operation for presentation in, for example, the Edit menu's Undo/Redo operations
+	 */
+	void execute(Runnable operation, String label);
+
+	/**
+	 * Execute a callable (an operation returning a result).
+	 * 
+	 * @param operation
+	 *        the operation to execute
+	 * @param label
+	 *        an optional label to associate with the operation for presentation in, for example, the Edit menu's Undo/Redo operations
+	 * @return the {@code operation}'s result
+	 */
+	<V> V execute(Callable<V> operation, String label);
+
+	//
+	// Nested types
+	//
+
+	class Default implements IAtomicOperationExecutor {
+
+		public void execute(final Runnable operation, String label) {
+			try {
+				operation.run();
+			} catch (OperationCanceledException e) {
+				// We cannot really implement cancel because there is not command/transaction to roll back
+			}
+		}
+
+		public <V> V execute(final Callable<V> operation, String label) {
+			class CallableWrapper implements Runnable {
+
+				V result;
+
+				@Override
+				public void run() {
+					try {
+						result = operation.call();
+					} catch (OperationCanceledException e) {
+						// Don't trap this one
+						throw e;
+					} catch (Exception e) {
+						Activator.log.error("Callable operation failed.", e); //$NON-NLS-1$
+						throw new OperationCanceledException(); // roll back
+					}
+				}
+			}
+
+			CallableWrapper wrapper = new CallableWrapper();
+
+			execute(wrapper, label);
+
+			return wrapper.result;
+		}
+
+	}
+}