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   *   Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you 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
   *
   *    https://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
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  package org.apache.cayenne.swing;
  
  import java.awt.Color;
  import java.awt.Component;
  import java.awt.event.ActionEvent;
  import java.awt.event.ActionListener;
  import java.awt.event.ItemListener;
  
  import javax.swing.JComboBox;
  import javax.swing.JComponent;
  
  import org.apache.cayenne.modeler.dialog.validator.ValidatorDialog;
  import org.apache.cayenne.modeler.undo.JComboBoxUndoListener;
  import org.apache.cayenne.validation.ValidationException;
  
  /**
   */
  public class ComboSelectionBinding extends BindingBase {
  
      protected JComboBox comboBox;
  
      protected Color defaultBGColor;
      protected Color errorColor;
      protected String defaultToolTip;
      protected String noSelectionValue;
  
      /**
       * Binds to update model for a combo box selection events. For editable combo boxes
       * model is updated whenever a new value is entered.
       */
      public ComboSelectionBinding(JComboBox comboBox, String expression,
              String noSelectionValue) {
          super(expression);
          this.comboBox = comboBox;
          this.noSelectionValue = noSelectionValue;
  
          // insert no selection value as first item in the combobox if it is not there
          if (noSelectionValue != null
                  && (comboBox.getItemCount() == 0 || comboBox.getItemAt(0) != noSelectionValue)) {
  
              comboBox.insertItemAt(noSelectionValue, 0);
          }
  
          comboBox.addActionListener(new ActionListener() {
  
              public void actionPerformed(ActionEvent e) {
                  if (!modelUpdateDisabled) {
                      updateModel();
                  }
              }
          });
  
          // init error colors
          initComponentDefaults();
      }
  
      protected void initComponentDefaults() {
          this.errorColor = ValidatorDialog.WARNING_COLOR;
  
          if (comboBox.getEditor() != null) {
  
              Component editor = comboBox.getEditor().getEditorComponent();
              if (editor instanceof JComponent) {
                  JComponent jEditor = (JComponent) editor;
                  this.defaultBGColor = jEditor.getBackground();
                  this.defaultToolTip = jEditor.getToolTipText();
              }
          }
      }
  
      public void updateView() {
          Object value = getValue();
          modelUpdateDisabled = true;
          try {
              clear();
              ItemListener[] listeners = comboBox.getItemListeners();
              for (ItemListener itemListener : listeners) {
                  if (itemListener instanceof JComboBoxUndoListener) {
                      //in order not to add event to undo list
                      ((JComboBoxUndoListener) itemListener).setIsUserAction(false);
                  }
              }
              if (value != null) {
                  this.comboBox.setSelectedItem(value.toString());
              }
              else if (noSelectionValue != null) {
                  this.comboBox.setSelectedItem(noSelectionValue);
              }
              else {
                  this.comboBox.setSelectedIndex(-1);
              }
          }
          finally {
              modelUpdateDisabled = false;
          }
      }
  
      protected void updateModel() {
          try {
              Object value = comboBox.getSelectedItem();
              if (noSelectionValue != null && noSelectionValue.equals(value)) {
                  value = null;
              }
              setValue(value);
              clear();
          }
          catch (ValidationException vex) {
              initWarning(vex.getLocalizedMessage());
          }
      }
  
      public Component getView() {
          return comboBox;
      }
  
      protected void clear() {
          if (comboBox.getEditor() != null) {
  
              Component editor = comboBox.getEditor().getEditorComponent();
              if (editor instanceof JComponent) {
                  JComponent jEditor = (JComponent) editor;
                  jEditor.setBackground(defaultBGColor);
                  jEditor.setToolTipText(defaultToolTip);
              }
          }
      }
  
      protected void initWarning(String message) {
          if (comboBox.getEditor() != null) {
  
              Component editor = comboBox.getEditor().getEditorComponent();
              if (editor instanceof JComponent) {
                  JComponent jEditor = (JComponent) editor;
                  jEditor.setBackground(errorColor);
                  jEditor.setToolTipText(message);
              }
          }
      }
  }
  