cache the "tree"

src/main/java/com/commafeed/backend/model/Models.java

@@ -0,0 +1,29 @@
+package com.commafeed.backend.model;
+
+import org.hibernate.Hibernate;
+import org.hibernate.HibernateException;
+import org.hibernate.proxy.HibernateProxy;
+import org.hibernate.proxy.LazyInitializer;
+
+public class Models {
+
+	/**
+	 * initialize a proxy
+	 */
+	public static void initialize(Object proxy) throws HibernateException {
+		Hibernate.initialize(proxy);
+	}
+
+	/**
+	 * extract the id from the proxy without initializing it
+	 */
+	public static Long getId(AbstractModel model) {
+		if (model instanceof HibernateProxy) {
+			LazyInitializer lazyInitializer = ((HibernateProxy) model).getHibernateLazyInitializer();
+			if (lazyInitializer.isUninitialized()) {
+				return (Long) lazyInitializer.getIdentifier();
+			}
+		}
+		return model.getId();
+	}
+}