+ /**
+ * Adds a random {@link GUID} as a value for <code>L0.identifier</code>
+ *
+ * @param graph
+ * @param component
+ * for which the identifier is added
+ * @param add
+ * <code>true</code> to invoke addLiteral, <code>false</code> to
+ * invoke claimLiteral
+ * @throws DatabaseException
+ */
+ public static void claimNewIdentifier(WriteGraph graph, Resource component, boolean add) throws DatabaseException {
+ Layer0 L0 = Layer0.getInstance(graph);
+ GUID guid = GUID.random();
+ if (add)
+ graph.addLiteral(component, L0.identifier, L0.identifier_Inverse, L0.GUID, guid, GUID.BINDING);
+ else
+ graph.claimLiteral(component, L0.identifier, L0.identifier_Inverse, L0.GUID, guid, GUID.BINDING);
+ }
+
+ /**
+ * Sets a new random unique identifier for the specified entity if it already
+ * has an identifier. If the entity does not have a previous identifier, nothing
+ * is done.
+ *
+ * @param graph
+ * @param entity
+ * for which the identifier is added
+ * @return <code>true</code> if the identifier was renewed, <code>false</code>
+ * otherwise
+ * @throws DatabaseException
+ * @see {@link #claimNewIdentifier(WriteGraph, Resource, boolean)}
+ */
+ public static boolean renewIdentifier(WriteGraph graph, Resource entity) throws DatabaseException {
+ Layer0 L0 = Layer0.getInstance(graph);
+ Statement stm = graph.getPossibleStatement(entity, L0.identifier);
+ if (stm != null) {
+ graph.claimValue(stm.getObject(), GUID.random(), GUID.BINDING);
+ return true;
+ }
+ return false;
+ }
+