+ * The following conditions must be met in order for the configuration to be
+ * considered valid:
+ *
+ *
Exactly one of {@link #randomId()} or {@link #withId(String)} must
+ * have been called.
+ *
The {@link #from(String) sender} must not be {@code null}.
+ *
Exactly one of {@link #currentTime()} or {@link #withTime(long)} must
+ * have been called.
+ *
The {@link #withText(String) text} must not be {@code null} and must
+ * contain something other than whitespace.
+ *
The {@link #to(String) post} have been set.
+ *
+ *
+ * @return The created post reply
+ * @throws IllegalStateException
+ * if this builderâs configuration is not valid
+ */
+ public PostReply build() throws IllegalStateException;
+
+}