package edu.jiangxin.apktoolbox.swing.extend.autocomplete;
   
   import org.apache.commons.lang3.StringUtils;
   import org.apache.commons.lang3.Strings;
   
   import javax.swing.*;
   import java.awt.*;
   import java.awt.event.KeyEvent;
   import java.awt.event.KeyListener;
  import java.util.Vector;
  
  class AutoCompleter<E> implements KeyListener {
      private JComboBox<E> comboBox;
      private JTextField textField;
      private ComboBoxModel<E> comboBoxModel;
  
      public AutoCompleter(JComboBox<E> comboBox) {
          if (comboBox == null) {
              throw new AutoCompleterInitException("comboBox is null");
          }
          this.comboBox = comboBox;
          ComboBoxEditor comboBoxEditor = comboBox.getEditor();
          if (comboBoxEditor == null) {
              throw new AutoCompleterInitException("comboBoxEditor is null");
          }
          Component component = comboBoxEditor.getEditorComponent();
          if (!(component instanceof JTextField)) {
              throw new AutoCompleterInitException("component is invalid");
          }
          this.textField = (JTextField) component;
          this.textField.addKeyListener(this);
          this.comboBoxModel = comboBox.getModel();
      }
  
      @Override
      public void keyTyped(KeyEvent e) {
          // do nothing
      }
  
      @Override
      public void keyPressed(KeyEvent e) {
          // do nothing
      }
  
      @Override
      public void keyReleased(KeyEvent e) {
          char keyChar = e.getKeyChar();
          if (Character.isAlphabetic(keyChar) || Character.isDigit(keyChar) || Character.isWhitespace(keyChar)
                  || keyChar == KeyEvent.VK_BACK_SPACE) {
              String text = textField.getText();
              autoComplete(text);
              textField.setText(text);
          }
      }
  
      protected void autoComplete(String text) {
          Vector<E> opts = getMatchingOptions(text);
          comboBox.setModel(new DefaultComboBoxModel<>(opts));
          if (comboBox.getItemCount() > 0) {
              comboBox.showPopup();
          }
      }
  
      private Vector<E> getMatchingOptions(String text) {
          Vector<E> vector = new Vector<>();
          ComboBoxModel<E> tmp = this.comboBoxModel;
          for (int i = 0; i < tmp.getSize(); i++) {
              E itemObj = tmp.getElementAt(i);
              if (StringUtils.isEmpty(text) || Strings.CI.contains(itemObj.toString(), text)) {
                  vector.add(itemObj);
              }
          }
          return vector;
      }
  
  }