1 files changed, 64 insertions, 0 deletions
diff --git a/plugins/uml/properties/org.eclipse.papyrus.uml.properties/src/org/eclipse/papyrus/uml/properties/databinding/UnsettableStringObservableValue.java b/plugins/uml/properties/org.eclipse.papyrus.uml.properties/src/org/eclipse/papyrus/uml/properties/databinding/UnsettableStringObservableValue.java
new file mode 100755
index 00000000000..4259e3eaf9b
--- /dev/null
+++ b/plugins/uml/properties/org.eclipse.papyrus.uml.properties/src/org/eclipse/papyrus/uml/properties/databinding/UnsettableStringObservableValue.java
@@ -0,0 +1,64 @@
+/*****************************************************************************
+ * Copyright (c) 2014 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
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *   CEA LIST - Initial API and implementation
+ *   Gabriel Pascual (ALL4TEC) gabriel.pascual@all4tec.net - bug 447698
+ *
+ *****************************************************************************/
+
+package org.eclipse.papyrus.uml.properties.databinding;
+
+import org.eclipse.core.databinding.observable.Realm;
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.emf.ecore.EStructuralFeature;
+import org.eclipse.emf.edit.domain.EditingDomain;
+import org.eclipse.emf.transaction.TransactionalEditingDomain;
+import org.eclipse.gmf.runtime.emf.type.core.requests.IEditCommandRequest;
+import org.eclipse.papyrus.infra.emf.requests.UnsetRequest;
+import org.eclipse.papyrus.infra.gmfdiag.common.databinding.GMFObservableValue;
+
+
+/**
+ * A specialized observable for string-valued attributes that are "unsettable" in the EMF sense, having a distinct unset state.
+ * For string features that have a {@code null} default, instead of accepting the empty string, the feature is simply unset so
+ * that it will be {@code null}.
+ *
+ * @since 3.3
+ */
+public class UnsettableStringObservableValue extends GMFObservableValue {
+
+	public UnsettableStringObservableValue(EObject eObject, EStructuralFeature eStructuralFeature, EditingDomain domain) {
+		super(eObject, eStructuralFeature, domain);
+	}
+
+	public UnsettableStringObservableValue(Realm realm, EObject eObject, EStructuralFeature eStructuralFeature, EditingDomain domain) {
+		super(realm, eObject, eStructuralFeature, domain);
+	}
+
+
+	@Override
+	protected IEditCommandRequest createSetRequest(TransactionalEditingDomain domain, EObject owner, EStructuralFeature feature, Object value) {
+
+		// Bug 447698 : It doesn't necessary to create UnsetRequest if the value is already null
+		if ("".equals(value)) {//$NON-NLS-1$
+
+			if ((feature.getDefaultValue() == null) && owner.eGet(eStructuralFeature) != null) {
+				// Unset the string attribute instead of making it an empty string
+				return new UnsetRequest(owner, feature);
+			}
+
+		} else {
+			return super.createSetRequest(domain, owner, feature, value);
+		}
+
+		return null;
+	}
+}