public synchronized void disconnectionNotification(String eventName,
						     Object source) {

    if (eventName.compareTo("trainingSet") == 0) {
      if (m_trainingProvider == source) {
	m_trainingProvider = null;
      }
    }
    if (eventName.compareTo("testSet") == 0) {
      if (m_testProvider == source) {
	m_testProvider = null;
      }
    }
    if (eventName.compareTo("dataSet") == 0) {
      if (m_dataProvider == source) {
	m_dataProvider = null;
      }
    }

    if (eventName.compareTo("instance") == 0) {
      if (m_instanceProvider == source) {
	m_instanceProvider = null;
      }
    }
  }