source: osm/applications/editors/josm/plugins/imagery-xml-bounds/src/net/boplicity/xmleditor/XmlTextPane.java

/*
 * Copyright 2006-2008 Kees de Kooter
 *
 * 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 net.boplicity.xmleditor;

import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.swing.JTextPane;
import javax.swing.text.BadLocationException;

/**
 * JTextPane implementation that can handle xml text. The IndentKeyListener
 * implements smart indenting.
 *
 * @author kees
 */
public class XmlTextPane extends JTextPane {

    private static final Logger LOGGER = Logger.getLogger(XmlTextPane.class.getName());
    private static final Character NEW_LINE = '\n';

    /**
     * Constructs a new {@code XmlTextPane}.
     */
    public XmlTextPane() {

        // Set editor kit
        this.setEditorKitForContentType("text/xml", new XmlEditorKit());
        this.setContentType("text/xml");

        addKeyListener(new IndentKeyListener());
    }

    private class IndentKeyListener implements KeyListener {

        private boolean enterFlag;

        @Override
        public void keyPressed(KeyEvent event) {
            enterFlag = false;
            if ((event.getKeyCode() == KeyEvent.VK_ENTER)
                && (event.getModifiers() == 0)
                && getSelectionStart() == getSelectionEnd()) {
                enterFlag = true;
                event.consume();
            }
        }

        @Override
        public void keyReleased(KeyEvent event) {
            if ((event.getKeyCode() == KeyEvent.VK_ENTER)
                && (event.getModifiers() == 0) && enterFlag) {
                event.consume();

                int start, end;
                String text = getText();

                int caretPosition = getCaretPosition();
                try {
                    if (text.charAt(caretPosition) == NEW_LINE) {
                        caretPosition--;
                    }
                } catch (IndexOutOfBoundsException e) {
                    LOGGER.log(Level.FINE, e.toString());
                }

                start = text.lastIndexOf(NEW_LINE, caretPosition) + 1;
                end = start;
                try {
                    if (text.charAt(start) != NEW_LINE) {
                        while (end < text.length()
                                && Character.isWhitespace(text.charAt(end))
                                && text.charAt(end) != NEW_LINE) {
                            end++;
                        }
                        if (end > start) {
                            getDocument()
                                    .insertString(
                                            getCaretPosition(),
                                            NEW_LINE
                                                    + text.substring(start,
                                                            end), null);
                        } else {
                            getDocument().insertString(getCaretPosition(),
                                    NEW_LINE.toString(), null);
                        }
                    } else {
                        getDocument().insertString(getCaretPosition(),
                                NEW_LINE.toString(), null);
                    }
                } catch (IndexOutOfBoundsException e) {
                    try {
                        getDocument().insertString(getCaretPosition(),
                                NEW_LINE.toString(), null);
                    } catch (BadLocationException e1) {
                        LOGGER.log(Level.WARNING, e1.toString());
                    }
                } catch (BadLocationException e) {
                    LOGGER.log(Level.WARNING, e.toString());
                }
            }
        }

        @Override
        public void keyTyped(KeyEvent e) {
            // Do nothing
        }
    }
}