1 files changed, 64 insertions, 0 deletions
diff --git a/plugins/infra/org.eclipse.papyrus.infra.ui/src/org/eclipse/papyrus/infra/ui/editor/reload/TreeViewerContext.java b/plugins/infra/org.eclipse.papyrus.infra.ui/src/org/eclipse/papyrus/infra/ui/editor/reload/TreeViewerContext.java
new file mode 100644
index 00000000000..6d70788326c
--- /dev/null
+++ b/plugins/infra/org.eclipse.papyrus.infra.ui/src/org/eclipse/papyrus/infra/ui/editor/reload/TreeViewerContext.java
@@ -0,0 +1,64 @@
+/*
+ * 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.ui.editor.reload;
+
+import java.util.Collection;
+import java.util.List;
+
+import org.eclipse.jface.viewers.AbstractTreeViewer;
+import org.eclipse.jface.viewers.StructuredSelection;
+
+import com.google.common.collect.Lists;
+
+/**
+ * A convenient context object for {@link IEditorReloadListener}s to store in an {@link EditorReloadEvent} to capture and restore
+ * the expansion and selection state of nodes in a tree viewer.
+ */
+public abstract class TreeViewerContext<T> extends SelectionContext<AbstractTreeViewer, T> {
+
+	private List<T> expandedNodes = Lists.newArrayList();
+
+	public TreeViewerContext(AbstractTreeViewer viewer) {
+		super(viewer);
+
+		for (Object next : viewer.getExpandedElements()) {
+			T token = token(next);
+			if (token != null) {
+				expandedNodes.add(token);
+			}
+		}
+	}
+
+	@Override
+	public void restore(AbstractTreeViewer viewer) {
+		List<Object> expand = Lists.newArrayListWithCapacity(expandedNodes.size());
+		for (T next : expandedNodes) {
+			Object resolved = resolve(next);
+			if (resolved != null) {
+				expand.add(resolved);
+			}
+		}
+		setExpandedElements(viewer, expand);
+
+		super.restore(viewer);
+	}
+
+	@Override
+	protected void setSelection(AbstractTreeViewer viewer, List<?> selection) {
+		viewer.setSelection(new StructuredSelection(selection), true);
+	}
+
+	protected void setExpandedElements(AbstractTreeViewer viewer, Collection<?> toExpand) {
+		viewer.setExpandedElements(toExpand.toArray());
+	}
+}