getReferenceAsString, getReferenceAsQN - from FaceQNP -> UddlQNP

com.epistimis.uddl/src/com/epistimis/uddl/UddlQNP.java

@@ -5,6 +5,7 @@
 import java.lang.invoke.MethodHandles;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.apache.log4j.Logger;
@@ -19,6 +20,8 @@
 import org.eclipse.xtext.naming.DefaultDeclarativeQualifiedNameProvider;
 import org.eclipse.xtext.naming.IQualifiedNameConverter;
 import org.eclipse.xtext.naming.QualifiedName;
+import org.eclipse.xtext.nodemodel.INode;
+import org.eclipse.xtext.nodemodel.util.NodeModelUtils;
 //import org.eclipse.xtext.xbase.scoping.XbaseQualifiedNameProvider;
 import org.eclipse.emf.ecore.util.EContentsEList;
 
@@ -135,6 +138,37 @@ public QualifiedName minimalQualifiedName(EObject obj, String qnPrefix) {
 
 	}
 
+	/**
+	 * Per this (https://www.eclipse.org/forums/index.php?t=msg&th=1084491&goto=1776641&)
+	 * we can't use cross references in a QNP. Instead, we can grab the actual text
+	 * of the cross reference using NodeModelUtils (https://archive.eclipse.org/modeling/tmf/xtext/javadoc/2.3/org/eclipse/xtext/nodemodel/util/NodeModelUtils.html)
+	 * (which is what we want anyway).
+	 * 
+	 * Note this is likely to be a QN - and we need the entire thing to make sure we don't have name
+	 * collisions.
+	 * 
+	 * NOTE also: When using a QN as a node in a larger qualified name, we can't use it in its default
+	 * format because it will include '.' separators that would make it look like multiple segments.
+	 * That means we need to convert the entire thing into a string that uses a different separator.
+	 * Ideally, the replacement separator should not be something that would otherwise be used in 
+	 * a single node (e.g. '_') because that could result in name collisions.
+	 */
+	public static String getReferenceAsString(EObject obj, String featureName) {
+		EStructuralFeature refFeature = obj.eClass().getEStructuralFeature(featureName);
+		// Should only be 1 node
+		List<INode> nodes = NodeModelUtils.findNodesForFeature(obj, refFeature);
+		INode node = nodes.get(0);
+		return node.getText().trim();
+	}
+
+	public QualifiedName getReferenceAsQN(EObject obj, String featureName) {
+		String qnString = getReferenceAsString(obj,featureName);
+
+		// Since the string may itself be a qualified name, we need to parse it into segments
+		QualifiedName refQN = converter.toQualifiedName(qnString);
+		return refQN;
+	}
+
 	/**
 	 * Return the shortest QN that will work as a valid reference, taking
 	 * into account all the imported namespaces in the resource where the reference