Transfer of the settings from the NodeModel to the NodeDialog is realized by implementing the validateSettings, loadValidatedSettings and saveSettings methods. All this methods can be safely delegated to the SettingsModels. In the validateSettings method a check is made to see if the values are present and valid (for example in a valid range, etc.).
@Override
protected void validateSettings(final NodeSettingsRO settings)
throws InvalidSettingsException {
m_numberOfBins.validateSettings(settings);
m_column.validateSettings(settings);
}