/*
File: JiraS16MaximumMatch.java ; This file is part of Twister.
Version: 2.001
Copyright (C) 2012-2013 , Luxoft
Authors: Andrei Costachi <acostachi@luxoft.com>
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.
*/
import javax.swing.*;
import javax.swing.text.*;
import java.awt.event.*;
public class JiraS16MaximumMatch extends PlainDocument {
JComboBox comboBox;
ComboBoxModel model;
JTextComponent editor;
// flag to indicate if setSelectedItem has been called
// subsequent calls to remove/insertString should be ignored
boolean selecting=false;
boolean hidePopupOnFocusLoss;
boolean hitBackspace=false;
boolean hitBackspaceOnSelection;
public JiraS16MaximumMatch(final JComboBox comboBox) {
this.comboBox = comboBox;
model = comboBox.getModel();
editor = (JTextComponent) comboBox.getEditor().getEditorComponent();
editor.setDocument(this);
comboBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (!selecting) highlightCompletedText(0);
}
});
editor.addKeyListener(new KeyAdapter() {
public void keyPressed(KeyEvent e) {
if (comboBox.isDisplayable()) comboBox.setPopupVisible(true);
hitBackspace=false;
switch (e.getKeyCode()) {
// determine if the pressed key is backspace (needed by the remove method)
case KeyEvent.VK_BACK_SPACE : hitBackspace=true;
hitBackspaceOnSelection=editor.getSelectionStart()!=editor.getSelectionEnd();
break;
// ignore delete key
case KeyEvent.VK_DELETE : e.consume();
comboBox.getToolkit().beep();
break;
}
}
});
// Bug 5100422 on Java 1.5: Editable JComboBox won't hide popup when tabbing out
hidePopupOnFocusLoss=System.getProperty("java.version").startsWith("1.5");
// Highlight whole text when gaining focus
editor.addFocusListener(new FocusAdapter() {
public void focusGained(FocusEvent e) {
highlightCompletedText(0);
}
public void focusLost(FocusEvent e) {
// Workaround for Bug 5100422 - Hide Popup on focus loss
if (hidePopupOnFocusLoss) comboBox.setPopupVisible(false);
}
});
// Handle initially selected object
Object selected = comboBox.getSelectedItem();
if (selected!=null) setText(selected.toString());
highlightCompletedText(0);
}
public void remove(int offs, int len) throws BadLocationException {
// return immediately when selecting an item
if (selecting) return;
if (hitBackspace) {
// user hit backspace => move the selection backwards
// old item keeps being selected
if (offs>0) {
if (hitBackspaceOnSelection) offs--;
} else {
// User hit backspace with the cursor positioned on the start => beep
comboBox.getToolkit().beep(); // when available use: UIManager.getLookAndFeel().provideErrorFeedback(comboBox);
}
highlightCompletedText(offs);
} else {
super.remove(offs, len);
}
}
public void insertString(int offs, String str, AttributeSet a) throws BadLocationException {
// return immediately when selecting an item
if (selecting) return;
// insert the string into the document
super.insertString(offs, str, a);
// lookup and select a matching item
boolean match=false;
Object item = lookupItem(getText(0, getLength()));
if (item != null) {
match=true;
setSelectedItem(item);
} else {
// keep old item selected if there is no match
item = comboBox.getSelectedItem();
// imitate no insert (later on offs will be incremented by str.length(): selection won't move forward)
offs = offs-str.length();
// provide feedback to the user that his input has been received but can not be accepted
comboBox.getToolkit().beep(); // when available use: UIManager.getLookAndFeel().provideErrorFeedback(comboBox);
}
if (match) offs = getMaximumMatchingOffset(getText(0, getLength()), item);
else offs+=str.length();
setText(item.toString());
// select the completed part
highlightCompletedText(offs);
}
private void setText(String text) {
try {
// remove all text and insert the completed string
super.remove(0, getLength());
super.insertString(0, text, null);
} catch (BadLocationException e) {
throw new RuntimeException(e.toString());
}
}
private void highlightCompletedText(int start) {
editor.setCaretPosition(getLength());
editor.moveCaretPosition(start);
}
private void setSelectedItem(Object item) {
selecting = true;
model.setSelectedItem(item);
selecting = false;
}
private Object lookupItem(String pattern) {
Object selectedItem = model.getSelectedItem();
// only search for a different item if the currently selected does not match
if (selectedItem != null && startsWithIgnoreCase(selectedItem.toString(), pattern)) {
return selectedItem;
} else {
// iterate over all items
for (int i=0, n=model.getSize(); i < n; i++) {
Object currentItem = model.getElementAt(i);
// current item starts with the pattern?
if (startsWithIgnoreCase(currentItem.toString(), pattern)) {
return currentItem;
}
}
}
// no item starts with the pattern => return null
return null;
}
// checks if str1 starts with str2 - ignores case
private boolean startsWithIgnoreCase(String str1, String str2) {
return str1.toUpperCase().startsWith(str2.toUpperCase());
}
// calculates how many characters are predetermined by the given pattern.
private int getMaximumMatchingOffset(String pattern, Object selectedItem) {
String selectedAsString=selectedItem.toString();
int match=selectedAsString.length();
// look for items that match the given pattern
for (int i=0, n=model.getSize(); i < n; i++) {
String itemAsString = model.getElementAt(i).toString();
if (startsWithIgnoreCase(itemAsString, pattern)) {
// current item matches the pattern
// how many leading characters have the selected and the current item in common?
int tmpMatch=equalStartLength(itemAsString, selectedAsString);
if (tmpMatch < match) match=tmpMatch;
}
}
return match;
}
// returns how many leading characters two strings have in common?
private static int equalStartLength(String str1, String str2) {
char[] ch1 = str1.toUpperCase().toCharArray();
char[] ch2 = str2.toUpperCase().toCharArray();
int n = ch1.length>ch2.length?ch2.length:ch1.length;
for (int i=0; i<n; i++) {
if (ch1[i]!=ch2[i]) return i;
}
return n;
}
}