/** Update the attributes´ value based on the associated components. */
 public void applyValues() {
   MarvinPluginWindowComponent filterComp;
   enumComponents = hashComponents.elements();
   while (enumComponents.hasMoreElements()) {
     filterComp = enumComponents.nextElement();
     if (filterComp.getAttributes() != null) {
       filterComp.getAttributes().set(filterComp.getAttributeID(), getValue(filterComp));
     }
   }
 }
  /**
   * @param plgComp - graphical component;
   * @return the value associated with the specified component
   */
  public Object getValue(MarvinPluginWindowComponent plgComp) {
    String l_id = plgComp.getAttributeID();
    MarvinAttributes attr = plgComp.getAttributes();
    JComponent comp = plgComp.getComponent();

    switch (plgComp.getType()) {
      case COMPONENT_TEXTFIELD:
        return stringToType(((JTextField) comp).getText(), attr.get(l_id));
      case COMPONENT_COMBOBOX:
        return (((JComboBox) comp).getSelectedItem());
      case COMPONENT_SLIDER:
        return (((JSlider) comp).getValue());
      case COMPONENT_TEXTAREA:
        return (((JTextArea) comp).getText());
      case COMPONENT_CHECKBOX:
        return (((JCheckBox) comp).isSelected());
      case COMPONENT_MATRIX_PANEL:
        return (((MarvinMatrixPanel) comp).getValue());
    }
    return null;
  }