EditorPaneExample9.java Source code

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Here is the source code for EditorPaneExample9.java

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/*
Core SWING Advanced Programming 
By Kim Topley
ISBN: 0 13 083292 8       
Publisher: Prentice Hall  
*/

import java.awt.Color;
import java.awt.Cursor;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.net.URLConnection;
import java.util.StringTokenizer;

import javax.swing.JCheckBox;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.text.BadLocationException;
import javax.swing.text.ChangedCharSetException;
import javax.swing.text.Document;
import javax.swing.text.html.HTMLDocument;
import javax.swing.text.html.HTMLEditorKit;

public class EditorPaneExample9 extends JFrame {
    public EditorPaneExample9() {
        super("JEditorPane Example 9");
        pane = new JEditorPane();
        pane.setEditable(false); // Read-only
        getContentPane().add(new JScrollPane(pane), "Center");

        // Build the panel of controls
        JPanel panel = new JPanel();

        panel.setLayout(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();
        c.gridwidth = 1;
        c.gridheight = 1;
        c.anchor = GridBagConstraints.EAST;
        c.fill = GridBagConstraints.NONE;
        c.weightx = 0.0;
        c.weighty = 0.0;

        JLabel urlLabel = new JLabel("URL: ", JLabel.RIGHT);
        panel.add(urlLabel, c);
        JLabel loadingLabel = new JLabel("State: ", JLabel.RIGHT);
        c.gridy = 1;
        panel.add(loadingLabel, c);
        JLabel typeLabel = new JLabel("Type: ", JLabel.RIGHT);
        c.gridy = 2;
        panel.add(typeLabel, c);
        c.gridy = 3;
        panel.add(new JLabel(LOAD_TIME), c);

        c.gridy = 4;
        c.gridwidth = 2;
        c.weightx = 1.0;
        c.anchor = GridBagConstraints.WEST;
        onlineLoad = new JCheckBox("Online Load");
        panel.add(onlineLoad, c);
        onlineLoad.setSelected(true);
        onlineLoad.setForeground(typeLabel.getForeground());

        c.gridx = 1;
        c.gridy = 0;
        c.anchor = GridBagConstraints.EAST;
        c.fill = GridBagConstraints.HORIZONTAL;

        textField = new JTextField(32);
        panel.add(textField, c);
        loadingState = new JLabel(spaces, JLabel.LEFT);
        loadingState.setForeground(Color.black);
        c.gridy = 1;
        panel.add(loadingState, c);
        loadedType = new JLabel(spaces, JLabel.LEFT);
        loadedType.setForeground(Color.black);
        c.gridy = 2;
        panel.add(loadedType, c);
        timeLabel = new JLabel("");
        c.gridy = 3;
        panel.add(timeLabel, c);

        getContentPane().add(panel, "South");

        // Change page based on text field
        textField.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                String url = textField.getText();

                try {
                    // Check if the new page and the old
                    // page are the same.
                    URL newURL = new URL(url);
                    URL loadedURL = pane.getPage();
                    if (loadedURL != null && loadedURL.sameFile(newURL)) {
                        return;
                    }

                    // Try to display the page
                    textField.setEnabled(false); // Disable input
                    textField.paintImmediately(0, 0, textField.getSize().width, textField.getSize().height);
                    setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
                    // Busy cursor
                    loadingState.setText("Loading...");
                    loadingState.paintImmediately(0, 0, loadingState.getSize().width,
                            loadingState.getSize().height);
                    loadedType.setText("");
                    loadedType.paintImmediately(0, 0, loadedType.getSize().width, loadedType.getSize().height);

                    timeLabel.setText("");
                    timeLabel.paintImmediately(0, 0, timeLabel.getSize().width, timeLabel.getSize().height);

                    startTime = System.currentTimeMillis();

                    // Choose the loading method
                    if (onlineLoad.isSelected()) {
                        // Usual load via setPage
                        pane.setPage(url);
                        loadedType.setText(pane.getContentType());
                    } else {
                        pane.setContentType("text/html");
                        loadedType.setText(pane.getContentType());
                        if (loader == null) {
                            loader = new HTMLDocumentLoader();
                        }
                        HTMLDocument doc = loader.loadDocument(new URL(url));
                        loadComplete();
                        pane.setDocument(doc);
                        displayLoadTime();
                    }
                } catch (Exception e) {
                    System.out.println(e);
                    JOptionPane.showMessageDialog(pane, new String[] { "Unable to open file", url },
                            "File Open Error", JOptionPane.ERROR_MESSAGE);
                    loadingState.setText("Failed");
                    textField.setEnabled(true);
                    setCursor(Cursor.getDefaultCursor());
                }
            }
        });

        // Listen for page load to complete
        pane.addPropertyChangeListener(new PropertyChangeListener() {
            public void propertyChange(PropertyChangeEvent evt) {
                if (evt.getPropertyName().equals("page")) {
                    loadComplete();
                    displayLoadTime();
                }
            }
        });
    }

    public void loadComplete() {
        loadingState.setText("Page loaded.");
        textField.setEnabled(true); // Allow entry of new URL
        setCursor(Cursor.getDefaultCursor());
    }

    public void displayLoadTime() {
        double loadingTime = ((double) (System.currentTimeMillis() - startTime)) / 1000d;
        timeLabel.setText(loadingTime + " seconds");
    }

    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
        } catch (Exception evt) {
        }

        JFrame f = new EditorPaneExample9();
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent evt) {
                System.exit(0);
            }
        });
        f.setSize(500, 400);
        f.setVisible(true);
    }

    static final String spaces = "                    ";

    static final String LOAD_TIME = "Load time: ";

    private JCheckBox onlineLoad;

    private HTMLDocumentLoader loader;

    private JLabel loadingState;

    private JLabel timeLabel;

    private JLabel loadedType;

    private JTextField textField;

    private JEditorPane pane;

    private long startTime;
}

class HTMLDocumentLoader {
    public HTMLDocument loadDocument(HTMLDocument doc, URL url, String charSet) throws IOException {
        doc.putProperty(Document.StreamDescriptionProperty, url);

        /*
         * This loop allows the document read to be retried if the character
         * encoding changes during processing.
         */
        InputStream in = null;
        boolean ignoreCharSet = false;

        for (;;) {
            try {
                // Remove any document content
                doc.remove(0, doc.getLength());

                URLConnection urlc = url.openConnection();
                in = urlc.getInputStream();
                Reader reader = (charSet == null) ? new InputStreamReader(in) : new InputStreamReader(in, charSet);

                HTMLEditorKit.Parser parser = getParser();
                HTMLEditorKit.ParserCallback htmlReader = getParserCallback(doc);
                parser.parse(reader, htmlReader, ignoreCharSet);
                htmlReader.flush();

                // All done
                break;
            } catch (BadLocationException ex) {
                // Should not happen - throw an IOException
                throw new IOException(ex.getMessage());
            } catch (ChangedCharSetException e) {
                // The character set has changed - restart
                charSet = getNewCharSet(e);

                // Prevent recursion by suppressing further exceptions
                ignoreCharSet = true;

                // Close original input stream
                in.close();

                // Continue the loop to read with the correct encoding
            }
        }

        return doc;
    }

    public HTMLDocument loadDocument(URL url, String charSet) throws IOException {
        return loadDocument((HTMLDocument) kit.createDefaultDocument(), url, charSet);
    }

    public HTMLDocument loadDocument(URL url) throws IOException {
        return loadDocument(url, null);
    }

    // Methods that allow customization of the parser and the callback
    public synchronized HTMLEditorKit.Parser getParser() {
        if (parser == null) {
            try {
                Class c = Class.forName("javax.swing.text.html.parser.ParserDelegator");
                parser = (HTMLEditorKit.Parser) c.newInstance();
            } catch (Throwable e) {
            }
        }
        return parser;
    }

    public synchronized HTMLEditorKit.ParserCallback getParserCallback(HTMLDocument doc) {
        return doc.getReader(0);
    }

    protected String getNewCharSet(ChangedCharSetException e) {
        String spec = e.getCharSetSpec();
        if (e.keyEqualsCharSet()) {
            // The event contains the new CharSet
            return spec;
        }

        // The event contains the content type
        // plus ";" plus qualifiers which may
        // contain a "charset" directive. First
        // remove the content type.
        int index = spec.indexOf(";");
        if (index != -1) {
            spec = spec.substring(index + 1);
        }

        // Force the string to lower case
        spec = spec.toLowerCase();

        StringTokenizer st = new StringTokenizer(spec, " \t=", true);
        boolean foundCharSet = false;
        boolean foundEquals = false;
        while (st.hasMoreTokens()) {
            String token = st.nextToken();
            if (token.equals(" ") || token.equals("\t")) {
                continue;
            }
            if (foundCharSet == false && foundEquals == false && token.equals("charset")) {
                foundCharSet = true;
                continue;
            } else if (foundEquals == false && token.equals("=")) {
                foundEquals = true;
                continue;
            } else if (foundEquals == true && foundCharSet == true) {
                return token;
            }

            // Not recognized
            foundCharSet = false;
            foundEquals = false;
        }

        // No charset found - return a guess
        return "8859_1";
    }

    protected static HTMLEditorKit kit;

    protected static HTMLEditorKit.Parser parser;

    static {
        kit = new HTMLEditorKit();
    }
}