import info.magnolia.ui.framework.message.MessagesManager;
import info.magnolia.ui.api.message.Message;
 
def clearNotificationsForUser(userName) {
    archived= 0
    messagesManager = info.magnolia.objectfactory.Components.getComponent(info.magnolia.ui.framework.message.MessagesManager);

    session = ctx.getJCRSession("messages")
    qm = session.getWorkspace().getQueryManager()
    query="select * from [mgnl:systemMessage] where ISDESCENDANTNODE('/superuser')";
 
    q = qm.createQuery(query, "JCR-SQL2")
    results = q.execute()
    messages = NodeUtil.asList(NodeUtil.asIterable(results.getNodes()))
 
    for (message in messages) {
       ++archived
       String id = message.getProperty("id").getValue().getString();
       messagesManager.clearMessage(userName, id);
 
    }
    println("archived "+archived+" notifications")
    session.save();
 
}
 
clearNotificationsForUser('superuser');