content: /*
   * Created on Nov 12, 2008
   * 
   * 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.
   * 
   * Copyright @2008-2013 the original author or authors.
   */
  package org.fest.swing.driver;
  
  import static org.fest.swing.edt.GuiActionRunner.execute;
  import static org.fest.util.Preconditions.checkNotNull;
  
  import javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  import javax.swing.JComboBox;
  
  import org.fest.swing.annotation.RunsInEDT;
  import org.fest.swing.cell.JComboBoxCellReader;
  import org.fest.swing.edt.GuiQuery;
  import org.fest.swing.util.Pair;
  
  /**
   * Returns the selected value of a {@code JComboBox} as plain text. This query is executed in the event dispatch thread
   * (EDT.)
   * 
   * @author Alex Ruiz
   */
  final class JComboBoxSelectionValueQuery {
    private static final Pair<Boolean, String> NO_SELECTION = Pair.of(false, null);
  
    @RunsInEDT
    static @Nonnull Pair<Boolean, String> selection(final @Nonnull JComboBox comboBox,
        final @Nonnull JComboBoxCellReader cellReader) {
      Pair<Boolean, String> result = execute(new GuiQuery<Pair<Boolean, String>>() {
        @Override
        protected @Nullable Pair<Boolean, String> executeInEDT() {
          int selectedIndex = comboBox.getSelectedIndex();
          if (selectedIndex == -1) {
            return valueForNoSelection(comboBox);
          }
          return selection(cellReader.valueAt(comboBox, selectedIndex));
        }
      });
      return checkNotNull(result);
    }
  
    private static @Nonnull Pair<Boolean, String> valueForNoSelection(@Nonnull JComboBox comboBox) {
      if (!comboBox.isEditable()) {
        return NO_SELECTION;
      }
      Object selectedItem = comboBox.getSelectedItem();
      if (selectedItem instanceof String) {
        return selection((String) selectedItem);
      }
      if (selectedItem != null) {
        return selection(selectedItem.toString());
      }
      return NO_SELECTION;
    }
  
    private static @Nonnull Pair<Boolean, String> selection(@Nullable String selection) {
      return Pair.of(true, selection);
    }
  
    private JComboBoxSelectionValueQuery() {}
  }
  