/*
    * Metis: Java Data Framework
    * Copyright 2012-2026. Tony Washer
    *
    * Licensed under the Apache License, Version 2.0 (the "License"); you may not
    * use this file except in compliance with the License.  You may obtain a copy
    * of the License at
    *
    *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations under
   * the License.
   */
  package io.github.tonywasher.joceanus.metis.ui;
  
  import io.github.tonywasher.joceanus.oceanus.base.OceanusException;
  import io.github.tonywasher.joceanus.oceanus.event.OceanusEventManager;
  import io.github.tonywasher.joceanus.oceanus.event.OceanusEventRegistrar;
  import io.github.tonywasher.joceanus.oceanus.event.OceanusEventRegistrar.OceanusEventProvider;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceEvent;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceResource;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceSet;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceSet.MetisBooleanPreference;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceSet.MetisDatePreference;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceSet.MetisEnumPreference;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceSet.MetisIntegerPreference;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceSet.MetisPreferenceId;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceSet.MetisPreferenceItem;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceSet.MetisStringPreference;
  import io.github.tonywasher.joceanus.metis.preference.MetisPreferenceType;
  import io.github.tonywasher.joceanus.tethys.api.base.TethysUIAlignment;
  import io.github.tonywasher.joceanus.tethys.api.base.TethysUIComponent;
  import io.github.tonywasher.joceanus.tethys.api.base.TethysUIConstant;
  import io.github.tonywasher.joceanus.tethys.api.base.TethysUIEvent;
  import io.github.tonywasher.joceanus.tethys.api.base.TethysUIGenericWrapper;
  import io.github.tonywasher.joceanus.tethys.api.button.TethysUIButton;
  import io.github.tonywasher.joceanus.tethys.api.control.TethysUICheckBox;
  import io.github.tonywasher.joceanus.tethys.api.control.TethysUIControlFactory;
  import io.github.tonywasher.joceanus.tethys.api.control.TethysUILabel;
  import io.github.tonywasher.joceanus.tethys.api.dialog.TethysUIDirectorySelector;
  import io.github.tonywasher.joceanus.tethys.api.dialog.TethysUIFileSelector;
  import io.github.tonywasher.joceanus.tethys.api.factory.TethysUIFactory;
  import io.github.tonywasher.joceanus.tethys.api.field.TethysUIDataEditField.TethysUIColorButtonField;
  import io.github.tonywasher.joceanus.tethys.api.field.TethysUIDataEditField.TethysUIDateButtonField;
  import io.github.tonywasher.joceanus.tethys.api.field.TethysUIDataEditField.TethysUIIntegerEditField;
  import io.github.tonywasher.joceanus.tethys.api.field.TethysUIDataEditField.TethysUIScrollButtonField;
  import io.github.tonywasher.joceanus.tethys.api.field.TethysUIDataEditField.TethysUIStringEditField;
  import io.github.tonywasher.joceanus.tethys.api.field.TethysUIFieldAttribute;
  import io.github.tonywasher.joceanus.tethys.api.field.TethysUIFieldType;
  import io.github.tonywasher.joceanus.tethys.api.menu.TethysUIScrollMenu;
  import io.github.tonywasher.joceanus.tethys.api.pane.TethysUIBorderPaneManager;
  import io.github.tonywasher.joceanus.tethys.api.pane.TethysUIFlowPaneManager;
  import io.github.tonywasher.joceanus.tethys.api.pane.TethysUIGridPaneManager;
  import io.github.tonywasher.joceanus.tethys.api.pane.TethysUIPaneFactory;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.function.Predicate;
  
  /**
   * Panel for editing a preference Set.
   */
  public class MetisPreferenceSetView
          implements OceanusEventProvider<MetisPreferenceEvent>, TethysUIComponent {
      /**
       * Colon String.
       */
      protected static final String STR_COLON = TethysUIConstant.STR_COLON;
  
      /**
       * Text for Preferences Title.
       */
      private static final String NLS_PREFERENCES = MetisPreferenceResource.UI_TITLE_PREFERENCES.getValue();
  
      /**
       * Text for Options Title.
       */
      private static final String NLS_OPTIONS = MetisPreferenceResource.UI_TITLE_OPTIONS.getValue();
  
      /**
       * The Event Manager.
       */
      private final OceanusEventManager<MetisPreferenceEvent> theEventManager;
  
      /**
       * The PreferenceSet for this panel.
       */
      private final MetisPreferenceSet thePreferences;
  
      /**
       * The Border Pane.
       */
      private final TethysUIBorderPaneManager thePane;
  
      /**
      * The Grid Pane.
      */
     private final TethysUIGridPaneManager theGrid;
 
     /**
      * The GUI factory.
      */
     private final TethysUIFactory<?> theGuiFactory;
 
     /**
      * The Element list.
      */
     private final List<PreferenceElement> theElements;
 
     /**
      * The Options Pane.
      */
     private TethysUIFlowPaneManager theOptions;
 
     /**
      * Constructor.
      *
      * @param pFactory       the GUI factory
      * @param pPreferenceSet the preference set
      */
     protected MetisPreferenceSetView(final TethysUIFactory<?> pFactory,
                                      final MetisPreferenceSet pPreferenceSet) {
         /* Store parameters */
         theGuiFactory = pFactory;
         thePreferences = pPreferenceSet;
 
         /* Create the event manager */
         theEventManager = new OceanusEventManager<>();
 
         /* Create the list */
         theElements = new ArrayList<>();
 
         /* Create the Grid Pane */
         final TethysUIPaneFactory myPanes = theGuiFactory.paneFactory();
         theGrid = myPanes.newGridPane();
 
         /* Loop through the preferences */
         for (MetisPreferenceItem myPref : thePreferences.getPreferences()) {
             /* Create element and add it to the list */
             final PreferenceElement myElement = allocatePreferenceElement(myPref);
             if (myElement != null) {
                 theElements.add(myElement);
             }
         }
 
         /* Create the border pane */
         thePane = myPanes.newBorderPane();
         thePane.setBorderTitle(NLS_PREFERENCES);
         thePane.setCentre(theGrid);
 
         /* If we have an options pane */
         if (theOptions != null) {
             /* Add to the end */
             thePane.setSouth(theOptions);
         }
 
         /* initialise the fields */
         updateFields();
     }
 
     /**
      * Obtain the GUI factory.
      *
      * @return the factory
      */
     protected TethysUIFactory<?> getFactory() {
         return theGuiFactory;
     }
 
     /**
      * Obtain the grid.
      *
      * @return the grid
      */
     protected TethysUIGridPaneManager getGrid() {
         return theGrid;
     }
 
     @Override
     public String toString() {
         return thePreferences.getName();
     }
 
     @Override
     public TethysUIComponent getUnderlying() {
         return thePane;
     }
 
     @Override
     public OceanusEventRegistrar<MetisPreferenceEvent> getEventRegistrar() {
         return theEventManager.getEventRegistrar();
     }
 
     /**
      * Does the Preference Set have changes.
      *
      * @return does the set have changes
      */
     boolean hasChanges() {
         return thePreferences.hasChanges();
     }
 
     /**
      * Reset changes.
      */
     void resetChanges() {
         /* Reset changes and clear flag */
         thePreferences.resetChanges();
 
         /* Update the fields */
         updateFields();
     }
 
     /**
      * Store changes.
      *
      * @throws OceanusException on error
      */
     void storeChanges() throws OceanusException {
         /* Reset changes and clear flag */
         thePreferences.storeChanges();
 
         /* Update the fields */
         updateFields();
     }
 
     /**
      * Update fields.
      */
     private void updateFields() {
         /* Update the viewer entry */
         thePreferences.updateViewerEntry();
 
         /* Loop through the fields */
         for (PreferenceElement myItem : theElements) {
             /* Update the field */
             myItem.updateField();
         }
     }
 
     /**
      * Notify changes.
      */
     protected void notifyChanges() {
         /* AutoCorrect the preferences */
         thePreferences.autoCorrectPreferences();
 
         /* Update the fields */
         updateFields();
 
         /* Notify listeners */
         theEventManager.fireEvent(MetisPreferenceEvent.PREFCHANGED);
     }
 
     /**
      * Allocate element.
      *
      * @param pItem the preference item
      * @return the element
      */
     protected PreferenceElement allocatePreferenceElement(final MetisPreferenceItem pItem) {
         if (pItem instanceof MetisEnumPreference<?> myEnum) {
             return new EnumPreferenceElement<>(myEnum);
         } else if (pItem instanceof MetisIntegerPreference myInt) {
             return new IntegerPreferenceElement(myInt);
         } else if (pItem instanceof MetisDatePreference myDate) {
             return new DatePreferenceElement(myDate);
         } else if (pItem instanceof MetisBooleanPreference myBool) {
             return new BooleanPreferenceElement(myBool);
         } else if (pItem instanceof MetisStringPreference myString) {
             final MetisPreferenceId myId = myString.getType();
             if (myId.equals(MetisPreferenceType.DIRECTORY)) {
                 return new DirectoryPreferenceElement(myString);
             } else if (myId.equals(MetisPreferenceType.FILE)) {
                 return new FilePreferenceElement(myString);
             } else if (myId.equals(MetisPreferenceType.COLOR)) {
                 return new ColorPreferenceElement(myString);
             } else {
                 return new StringPreferenceElement(myString);
             }
         } else {
             throw new IllegalArgumentException("Bad Preference Type: " + pItem.getType());
         }
     }
 
     /**
      * Determine Focus.
      */
     protected void determineFocus() {
         thePreferences.setFocus();
     }
 
     /**
      * PreferenceElement.
      */
     @FunctionalInterface
     protected interface PreferenceElement {
         /**
          * Update the field.
          */
         void updateField();
     }
 
     /**
      * String preference element.
      */
     private final class StringPreferenceElement
             implements PreferenceElement {
         /**
          * The Preference item.
          */
         private final MetisStringPreference theItem;
 
         /**
          * The Field item.
          */
         private final TethysUIStringEditField theField;
 
         /**
          * Constructor.
          *
          * @param pItem the item
          */
         StringPreferenceElement(final MetisStringPreference pItem) {
             /* Store parameters */
             theItem = pItem;
             theField = theGuiFactory.fieldFactory().newStringField();
             theField.setEditable(true);
 
             /* Create the label */
             final TethysUILabel myLabel = theGuiFactory.controlFactory().newLabel(pItem.getDisplay() + STR_COLON);
             myLabel.setAlignment(TethysUIAlignment.EAST);
 
             /* Add to the Grid Pane */
             theGrid.addCell(myLabel);
             theGrid.setCellAlignment(myLabel, TethysUIAlignment.EAST);
             theGrid.addCell(theField);
             theGrid.setCellColumnSpan(theField, 2);
             theGrid.allowCellGrowth(theField);
             theGrid.newRow();
 
             /* Create listener */
             theField.getEventRegistrar().addEventListener(e -> {
                 pItem.setValue(theField.getValue());
                 notifyChanges();
             });
         }
 
         @Override
         public void updateField() {
             /* Update the field */
             theField.setValue(theItem.getValue());
 
             /* Set changed indication */
             theField.setTheAttributeState(TethysUIFieldAttribute.CHANGED, theItem.isChanged());
             theField.adjustField();
 
             /* Handle hidden state */
             theField.setEnabled(!theItem.isHidden());
         }
     }
 
     /**
      * Integer preference element.
      */
     private final class IntegerPreferenceElement
             implements PreferenceElement {
         /**
          * The Preference item.
          */
         private final MetisIntegerPreference theItem;
 
         /**
          * The Field item.
          */
         private final TethysUIIntegerEditField theField;
 
         /**
          * The Label item.
          */
         private final TethysUILabel theRangeLabel;
 
         /**
          * Constructor.
          *
          * @param pItem the item
          */
         IntegerPreferenceElement(final MetisIntegerPreference pItem) {
             /* Store parameters */
             theItem = pItem;
             theField = theGuiFactory.fieldFactory().newIntegerField();
             theField.setEditable(true);
             theField.setPreferredWidth(TethysUIFieldType.INTEGER.getDefaultWidth());
 
             /* Create the label */
             final TethysUIControlFactory myControls = theGuiFactory.controlFactory();
             final TethysUILabel myLabel = myControls.newLabel(pItem.getDisplay() + STR_COLON);
             myLabel.setAlignment(TethysUIAlignment.EAST);
 
             /* Create the range label */
             theRangeLabel = myControls.newLabel();
 
             /* Add to the Grid Pane */
             theGrid.addCell(myLabel);
             theGrid.setCellAlignment(myLabel, TethysUIAlignment.EAST);
             theGrid.addCell(theField);
             theGrid.addCell(theRangeLabel);
             theGrid.allowCellGrowth(theRangeLabel);
             theGrid.newRow();
 
             /* Create listener */
             theField.getEventRegistrar().addEventListener(e -> {
                 pItem.setValue(theField.getValue());
                 notifyChanges();
             });
         }
 
         @Override
         public void updateField() {
             /* Update the field */
             theField.setValue(theItem.getValue());
 
             /* handle the range */
             handleRange();
 
             /* Set changed indication */
             theField.setTheAttributeState(TethysUIFieldAttribute.CHANGED, theItem.isChanged());
             theField.adjustField();
 
             /* Handle hidden state */
             theField.setEnabled(!theItem.isHidden());
         }
 
         /**
          * handle range.
          */
         private void handleRange() {
             /* Access the minimum/maximum */
             final Integer myMin = theItem.getMinimum();
             final Integer myMax = theItem.getMaximum();
             final boolean hasMin = myMin != null;
             final boolean hasMax = myMax != null;
 
             /* Set the valid range */
             theField.setValidator(p -> (hasMin && p < myMin) || (hasMax && p > myMax)
                     ? MetisPreferenceResource.UI_RANGE_ERROR.getValue()
                     : null);
             theRangeLabel.setText(null);
 
             /* If we have a minimum or maximum */
             if (hasMin || hasMax) {
                 /* Format the details */
                 final StringBuilder myBuilder = new StringBuilder();
 
                 /* Handle minimum */
                 if (hasMin) {
                     myBuilder.append(MetisPreferenceResource.UI_RANGE_MIN.getValue());
                     myBuilder.append(' ');
                     myBuilder.append(myMin);
                     if (hasMax) {
                         myBuilder.append(", ");
                     }
                 }
 
                 /* Handle maximum */
                 if (hasMax) {
                     myBuilder.append(MetisPreferenceResource.UI_RANGE_MAX.getValue());
                     myBuilder.append(' ');
                     myBuilder.append(myMax);
                 }
 
                 /* Format the field */
                 theRangeLabel.setText(myBuilder.toString());
             }
         }
     }
 
     /**
      * Boolean preference element.
      */
     private final class BooleanPreferenceElement
             implements PreferenceElement {
         /**
          * The Preference item.
          */
         private final MetisBooleanPreference theItem;
 
         /**
          * The CheckBox item.
          */
         private final TethysUICheckBox theCheckBox;
 
         /**
          * Constructor.
          *
          * @param pItem the item
          */
         BooleanPreferenceElement(final MetisBooleanPreference pItem) {
             /* Store parameters */
             theItem = pItem;
             theCheckBox = theGuiFactory.controlFactory().newCheckBox(pItem.getDisplay());
 
             /* Ensure the options pane */
             ensureOptionsPane();
 
             /* Add to the Options Pane */
             theOptions.addNode(theCheckBox);
 
             /* Create listener */
             theCheckBox.getEventRegistrar().addEventListener(TethysUIEvent.NEWVALUE, e -> {
                 pItem.setValue(theCheckBox.isSelected());
                 notifyChanges();
             });
         }
 
         @Override
         public void updateField() {
             /* Update the field */
             theCheckBox.setSelected(theItem.getValue());
 
             /* Set changed indication */
             theCheckBox.setChanged(theItem.isChanged());
 
             /* Handle hidden state */
             theCheckBox.setEnabled(!theItem.isHidden());
         }
 
         /**
          * ensure the options pane.
          */
         private void ensureOptionsPane() {
             /* If we haven't created the options yet */
             if (theOptions == null) {
                 /* create the options panel */
                 theOptions = theGuiFactory.paneFactory().newFlowPane();
                 theOptions.setBorderTitle(NLS_OPTIONS);
             }
         }
     }
 
     /**
      * Date preference element.
      */
     private final class DatePreferenceElement
             implements PreferenceElement {
         /**
          * The Preference item.
          */
         private final MetisDatePreference theItem;
 
         /**
          * The Field item.
          */
         private final TethysUIDateButtonField theField;
 
         /**
          * Constructor.
          *
          * @param pItem the item
          */
         DatePreferenceElement(final MetisDatePreference pItem) {
             /* Store parameters */
             theItem = pItem;
             theField = theGuiFactory.fieldFactory().newDateField();
             theField.setEditable(true);
 
             /* Create the label */
             final TethysUIControlFactory myControls = theGuiFactory.controlFactory();
             final TethysUILabel myLabel = myControls.newLabel(pItem.getDisplay() + STR_COLON);
             myLabel.setAlignment(TethysUIAlignment.EAST);
 
             /* Create the place-holder */
             final TethysUILabel myStub = myControls.newLabel();
 
             /* Add to the Grid Pane */
             theGrid.addCell(myLabel);
             theGrid.setCellAlignment(myLabel, TethysUIAlignment.EAST);
             theGrid.addCell(theField);
             theGrid.addCell(myStub);
             theGrid.allowCellGrowth(myStub);
             theGrid.newRow();
 
             /* Create listener */
             theField.getEventRegistrar().addEventListener(TethysUIEvent.NEWVALUE, e -> {
                 pItem.setValue(theField.getValue());
                 notifyChanges();
             });
         }
 
         @Override
         public void updateField() {
             /* Update the field */
             theField.setValue(theItem.getValue());
 
             /* Set changed indication */
             theField.setTheAttributeState(TethysUIFieldAttribute.CHANGED, theItem.isChanged());
             theField.adjustField();
 
             /* Handle hidden state */
             theField.setEnabled(!theItem.isHidden());
         }
     }
 
     /**
      * Enum preference element.
      *
      * @param <E> the enum type
      */
     private final class EnumPreferenceElement<E extends Enum<E>>
             implements PreferenceElement {
         /**
          * The Preference item.
          */
         private final MetisEnumPreference<E> theItem;
 
         /**
          * The Field item.
          */
         private final TethysUIScrollButtonField<TethysUIGenericWrapper> theField;
 
         /**
          * Constructor.
          *
          * @param pItem the item
          */
         @SuppressWarnings("unchecked")
         EnumPreferenceElement(final MetisEnumPreference<E> pItem) {
             /* Store parameters */
             theItem = pItem;
             theField = theGuiFactory.fieldFactory().newScrollField(TethysUIGenericWrapper.class);
             theField.setEditable(true);
 
             /* Create the label */
             final TethysUIControlFactory myControls = theGuiFactory.controlFactory();
             final TethysUILabel myLabel = myControls.newLabel(pItem.getDisplay() + STR_COLON);
             myLabel.setAlignment(TethysUIAlignment.EAST);
 
             /* Create the place-holder */
             final TethysUILabel myStub = myControls.newLabel();
 
             /* Add to the Grid Pane */
             theGrid.addCell(myLabel);
             theGrid.setCellAlignment(myLabel, TethysUIAlignment.EAST);
             theGrid.addCell(theField);
             theGrid.addCell(myStub);
             theGrid.allowCellGrowth(myStub);
             theGrid.newRow();
 
             /* Create listeners */
             theField.setMenuConfigurator(this::buildMenu);
             final OceanusEventRegistrar<TethysUIEvent> myRegistrar = theField.getEventRegistrar();
             myRegistrar.addEventListener(TethysUIEvent.NEWVALUE, e -> {
                 pItem.setValue((E) theField.getValue().getData());
                 notifyChanges();
             });
         }
 
         /**
          * Build menu.
          *
          * @param pMenu the menu
          */
         private void buildMenu(final TethysUIScrollMenu<TethysUIGenericWrapper> pMenu) {
             /* reset the menu */
             pMenu.removeAllItems();
 
             /* Obtain the filter */
             final Predicate<E> myFilter = theItem.getFilter();
 
             /* For all values */
             for (E myEnum : theItem.getValues()) {
                 /* If the element is not filtered */
                 if (myFilter.test(myEnum)) {
                     /* Create a new MenuItem and add it to the popUp */
                     pMenu.addItem(new TethysUIGenericWrapper(myEnum));
                 }
             }
         }
 
         @Override
         public void updateField() {
             /* Update the field */
             theField.setValue(new TethysUIGenericWrapper(theItem.getValue()));
 
             /* Set changed indication */
             theField.setTheAttributeState(TethysUIFieldAttribute.CHANGED, theItem.isChanged());
             theField.adjustField();
 
             /* Handle hidden state */
             theField.setEnabled(!theItem.isHidden());
         }
     }
 
     /**
      * Colour preference element.
      */
     private final class ColorPreferenceElement
             implements PreferenceElement {
         /**
          * The Preference item.
          */
         private final MetisStringPreference theItem;
 
         /**
          * The Field item.
          */
         private final TethysUIColorButtonField theField;
 
         /**
          * Constructor.
          *
          * @param pItem the item
          */
         ColorPreferenceElement(final MetisStringPreference pItem) {
             /* Store parameters */
             theItem = pItem;
             theField = theGuiFactory.fieldFactory().newColorField();
             theField.setEditable(true);
 
             /* Create the label */
             final TethysUIControlFactory myControls = theGuiFactory.controlFactory();
             final TethysUILabel myLabel = myControls.newLabel(pItem.getDisplay() + STR_COLON);
             myLabel.setAlignment(TethysUIAlignment.EAST);
 
             /* Create the place-holder */
             final TethysUILabel myStub = myControls.newLabel();
 
             /* Add to the Grid Pane */
             theGrid.addCell(myLabel);
             theGrid.setCellAlignment(myLabel, TethysUIAlignment.EAST);
             theGrid.addCell(theField);
             theGrid.addCell(myStub);
             theGrid.allowCellGrowth(myStub);
             theGrid.newRow();
 
             /* Create listener */
             theField.getEventRegistrar().addEventListener(e -> {
                 pItem.setValue(theField.getValue());
                 notifyChanges();
             });
         }
 
         @Override
         public void updateField() {
             /* Update the field */
             theField.setValue(theItem.getValue());
 
             /* Set changed indication */
             theField.setTheAttributeState(TethysUIFieldAttribute.CHANGED, theItem.isChanged());
             theField.adjustField();
 
             /* Handle hidden state */
             theField.setEnabled(!theItem.isHidden());
         }
     }
 
     /**
      * File preference element.
      */
     private final class FilePreferenceElement
             implements PreferenceElement {
         /**
          * The Preference item.
          */
         private final MetisStringPreference theItem;
 
         /**
          * The Field item.
          */
         private final TethysUIStringEditField theField;
 
         /**
          * The Button.
          */
         private final TethysUIButton theButton;
 
         /**
          * The File Selector.
          */
         private TethysUIFileSelector theSelector;
 
         /**
          * Constructor.
          *
          * @param pItem the item
          */
         FilePreferenceElement(final MetisStringPreference pItem) {
             /* Store parameters */
             theItem = pItem;
             theField = theGuiFactory.fieldFactory().newStringField();
             theField.setEditable(true);
 
             /* Create the button */
             theButton = theGuiFactory.buttonFactory().newButton();
             theButton.setTextOnly();
             theButton.setText(pItem.getDisplay());
 
             /* Add to the Grid Pane */
             theGrid.addCell(theButton);
             theGrid.addCell(theField);
             theGrid.setCellColumnSpan(theField, 2);
             theGrid.allowCellGrowth(theField);
             theGrid.newRow();
 
             /* Create listeners */
             theButton.getEventRegistrar().addEventListener(e -> handleDialog());
             theField.getEventRegistrar().addEventListener(e -> {
                 pItem.setValue(theField.getValue());
                 notifyChanges();
             });
         }
 
         @Override
         public void updateField() {
             /* Update the field */
             theField.setValue(theItem.getValue());
 
             /* Set changed indication */
             theField.setTheAttributeState(TethysUIFieldAttribute.CHANGED, theItem.isChanged());
             theField.adjustField();
 
             /* Handle hidden state */
             final boolean isEnabled = !theItem.isHidden();
             theField.setEnabled(isEnabled);
             theButton.setEnabled(isEnabled);
         }
 
         /**
          * Handle Dialog.
          */
         private void handleDialog() {
             ensureSelector();
             theSelector.setInitialFile(new File(theItem.getValue()));
             final File myFile = theSelector.selectFile();
             if (myFile != null) {
                 theItem.setValue(myFile.getAbsolutePath());
                 notifyChanges();
             }
         }
 
         /**
          * Ensure that selector is created.
          */
         private void ensureSelector() {
             if (theSelector == null) {
                 theSelector = theGuiFactory.dialogFactory().newFileSelector();
                 theSelector.setTitle(theItem.getDisplay());
             }
         }
     }
 
     /**
      * Directory preference element.
      */
     private final class DirectoryPreferenceElement
             implements PreferenceElement {
         /**
          * The Preference item.
          */
         private final MetisStringPreference theItem;
 
         /**
          * The Field item.
          */
         private final TethysUIStringEditField theField;
 
         /**
          * The Button.
          */
         private final TethysUIButton theButton;
 
         /**
          * The Directory Selector.
          */
         private TethysUIDirectorySelector theSelector;
 
         /**
          * Constructor.
          *
          * @param pItem the item
          */
         DirectoryPreferenceElement(final MetisStringPreference pItem) {
             /* Store parameters */
             theItem = pItem;
             theField = theGuiFactory.fieldFactory().newStringField();
             theField.setEditable(true);
 
             /* Create the button */
             theButton = theGuiFactory.buttonFactory().newButton();
             theButton.setTextOnly();
             theButton.setText(pItem.getDisplay());
 
             /* Add to the Grid Pane */
             theGrid.addCell(theButton);
             theGrid.addCell(theField);
             theGrid.setCellColumnSpan(theField, 2);
             theGrid.allowCellGrowth(theField);
             theGrid.newRow();
 
             /* Create listeners */
             theButton.getEventRegistrar().addEventListener(e -> handleDialog());
             theField.getEventRegistrar().addEventListener(e -> {
                 pItem.setValue(theField.getValue());
                 notifyChanges();
             });
         }
 
         @Override
         public void updateField() {
             /* Update the field */
             theField.setValue(theItem.getValue());
 
             /* Set changed indication */
             theField.setTheAttributeState(TethysUIFieldAttribute.CHANGED, theItem.isChanged());
             theField.adjustField();
 
             /* Handle hidden state */
             final boolean isEnabled = !theItem.isHidden();
             theField.setEnabled(isEnabled);
             theButton.setEnabled(isEnabled);
         }
 
         /**
          * Handle Dialog.
          */
         private void handleDialog() {
             ensureSelector();
             theSelector.setInitialDirectory(new File(theItem.getValue()));
             final File myDir = theSelector.selectDirectory();
             if (myDir != null) {
                 theItem.setValue(myDir.getAbsolutePath());
                 notifyChanges();
             }
         }
 
         /**
          * Ensure that selector is created.
          */
         private void ensureSelector() {
             if (theSelector == null) {
                 theSelector = theGuiFactory.dialogFactory().newDirectorySelector();
                 theSelector.setTitle(theItem.getDisplay());
             }
         }
     }
 }