JEditorPane Example 14 : Text EditorPane « Swing JFC « Java






JEditorPane Example 14

JEditorPane Example 14
    
/*
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.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Rectangle;
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.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.StringTokenizer;
import java.util.Vector;

import javax.swing.DefaultComboBoxModel;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
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.JTree;
import javax.swing.UIManager;
import javax.swing.event.HyperlinkEvent;
import javax.swing.event.HyperlinkListener;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.ChangedCharSetException;
import javax.swing.text.Document;
import javax.swing.text.Element;
import javax.swing.text.ElementIterator;
import javax.swing.text.StyleConstants;
import javax.swing.text.html.HTML;
import javax.swing.text.html.HTMLDocument;
import javax.swing.text.html.HTMLEditorKit;
import javax.swing.text.html.HTMLFrameHyperlinkEvent;
import javax.swing.text.html.StyleSheet;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;

public class EditorPaneExample14 extends JFrame {
  public EditorPaneExample14() {
    super("JEditorPane Example 14");

    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;

    urlCombo = new JComboBox();
    panel.add(urlCombo, c);
    urlCombo.setEditable(true);
    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");

    // Modify the default style sheet
    InputStream is = EditorPaneExample14.class
        .getResourceAsStream("changedDefault.css");
    if (is != null) {
      try {
        addToStyleSheet(editorKit.getStyleSheet(), is);
      } catch (IOException e) {
        System.out.println("Failed to modify default style sheet");
      }
    }

    // Allocate the empty tree model
    DefaultMutableTreeNode emptyRootNode = new DefaultMutableTreeNode(
        "Empty");
    emptyModel = new DefaultTreeModel(emptyRootNode);

    // Create and place the heading tree
    tree = new JTree(emptyModel);
    tree.setPreferredSize(new Dimension(200, 200));
    getContentPane().add(new JScrollPane(tree), "East");

    // Change page based on combo selection
    urlCombo.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent evt) {
        if (populatingCombo == true) {
          return;
        }
        Object selection = urlCombo.getSelectedItem();
        loadNewPage(selection);
      }
    });

    // Listen for page load to complete
    pane.addPropertyChangeListener(new PropertyChangeListener() {
      public void propertyChange(PropertyChangeEvent evt) {
        if (evt.getPropertyName().equals("page")) {
          loadComplete();
          displayLoadTime();
          populateCombo(findLinks(pane.getDocument(), null));
          TreeNode node = buildHeadingTree(pane.getDocument());
          tree.setModel(new DefaultTreeModel(node));
          enableInput();
          loadingPage = false;
        }
      }
    });

    // Listener for tree selection
    tree.addTreeSelectionListener(new TreeSelectionListener() {
      public void valueChanged(TreeSelectionEvent evt) {
        TreePath path = evt.getNewLeadSelectionPath();
        if (path != null) {
          DefaultMutableTreeNode node = (DefaultMutableTreeNode) path
              .getLastPathComponent();
          Object userObject = node.getUserObject();
          if (userObject instanceof Heading) {
            Heading heading = (Heading) userObject;
            try {
              Rectangle textRect = pane.modelToView(heading
                  .getOffset());
              textRect.y += 3 * textRect.height;
              pane.scrollRectToVisible(textRect);
            } catch (BadLocationException e) {
            }
          }
        }
      }
    });

    // Listener for hypertext events
    pane.addHyperlinkListener(new HyperlinkListener() {
      public void hyperlinkUpdate(HyperlinkEvent evt) {
        // Ignore hyperlink events if the frame is busy
        if (loadingPage == true) {
          return;
        }
        if (evt.getEventType() == HyperlinkEvent.EventType.ACTIVATED) {
          JEditorPane sp = (JEditorPane) evt.getSource();
          if (evt instanceof HTMLFrameHyperlinkEvent) {
            HTMLDocument doc = (HTMLDocument) sp.getDocument();
            doc
                .processHTMLFrameHyperlinkEvent((HTMLFrameHyperlinkEvent) evt);
          } else {
            loadNewPage(evt.getURL());
          }
        } else if (evt.getEventType() == HyperlinkEvent.EventType.ENTERED) {
          pane.setCursor(handCursor);
        } else if (evt.getEventType() == HyperlinkEvent.EventType.EXITED) {
          pane.setCursor(defaultCursor);
        }
      }
    });
  }

  public void loadNewPage(Object page) {
    try {
      loadingPage = true;

      // Check if the new page and the old
      // page are the same.
      URL url;
      if (page instanceof URL) {
        url = (URL) page;
      } else {
        url = new URL((String) page);
      }

      urlCombo.setSelectedItem(page);

      URL loadedURL = pane.getPage();
      if (loadedURL != null && loadedURL.sameFile(url)) {
        return;
      }

      // Try to display the page
      urlCombo.setEnabled(false); // Disable input
      urlCombo.paintImmediately(0, 0, urlCombo.getSize().width, urlCombo
          .getSize().height);
      setCursor(waitCursor); // 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);

      // Display an empty tree while loading
      tree.setModel(emptyModel);
      tree.paintImmediately(0, 0, tree.getSize().width,
          tree.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(url);
        loadComplete();
        pane.setDocument(doc);
        displayLoadTime();
        populateCombo(findLinks(doc, null));
        TreeNode node = buildHeadingTree(doc);
        tree.setModel(new DefaultTreeModel(node));
        enableInput();
        loadingPage = false;
      }
    } catch (Exception e) {
      System.out.println(e);
      JOptionPane.showMessageDialog(pane, new String[] {
          "Unable to open file", page.toString() },
          "File Open Error", JOptionPane.ERROR_MESSAGE);
      loadingState.setText("Failed");
      enableInput();
      loadingPage = false;
    }
  }

  public void loadComplete() {
    loadingState.setText("Page loaded.");
  }

  public void enableInput() {
    urlCombo.setEnabled(true); // Allow entry of new URL
    setCursor(defaultCursor);
    pane.setCursor(defaultCursor);
  }

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

  public void populateCombo(URL[] urls) {
    // Save existing selection
    Object o = urlCombo.getSelectedItem();
    populatingCombo = true;
    urlCombo.setModel(new DefaultComboBoxModel(urls));
    // Restore original selection
    urlCombo.setSelectedItem(o);
    populatingCombo = false;
  }

  public StyleSheet loadStyleSheet(InputStream is) throws IOException {
    StyleSheet s = new StyleSheet();
    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    s.loadRules(reader, null);
    reader.close();

    return s;
  }

  public void addToStyleSheet(StyleSheet s, InputStream is)
      throws IOException {
    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    s.loadRules(reader, null);
    reader.close();
  }

  public URL[] findLinks(Document doc, String protocol) {
    Vector links = new Vector();
    Vector urlNames = new Vector();
    URL baseURL = (URL) doc.getProperty(Document.StreamDescriptionProperty);

    if (doc instanceof HTMLDocument) {
      Element elem = doc.getDefaultRootElement();
      ElementIterator iterator = new ElementIterator(elem);

      while ((elem = iterator.next()) != null) {
        AttributeSet attrs = elem.getAttributes();
        Object link = attrs.getAttribute(HTML.Tag.A);
        if (link instanceof AttributeSet) {
          Object linkAttr = ((AttributeSet) link)
              .getAttribute(HTML.Attribute.HREF);
          if (linkAttr instanceof String) {
            try {
              URL linkURL = new URL(baseURL, (String) linkAttr);
              if (protocol == null
                  || protocol.equalsIgnoreCase(linkURL
                      .getProtocol())) {
                String linkURLName = linkURL.toString();
                if (urlNames.contains(linkURLName) == false) {
                  urlNames.addElement(linkURLName);
                  links.addElement(linkURL);
                }
              }
            } catch (MalformedURLException e) {
              // Ignore invalid links
            }
          }
        }
      }
    }

    URL[] urls = new URL[links.size()];
    links.copyInto(urls);
    links.removeAllElements();
    urlNames.removeAllElements();

    return urls;
  }

  public TreeNode buildHeadingTree(Document doc) {
    String title = (String) doc.getProperty(Document.TitleProperty);
    if (title == null) {
      title = "[No title]";
    }
    Heading rootHeading = new Heading(title, 0, 0);
    DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode(
        rootHeading);

    DefaultMutableTreeNode lastNode[] = new DefaultMutableTreeNode[7];
    int lastLevel = 0;
    lastNode[lastLevel] = rootNode;

    if (doc instanceof HTMLDocument) {
      Element elem = doc.getDefaultRootElement();
      ElementIterator iterator = new ElementIterator(elem);
      Heading heading;

      while ((heading = getNextHeading(doc, iterator)) != null) {
        // Add the node to the tree
        DefaultMutableTreeNode hNode = new DefaultMutableTreeNode(
            heading);
        int level = heading.getLevel();

        if (level > lastLevel) {
          for (int i = lastLevel + 1; i < level; i++) {
            lastNode[i] = null;
          }
          lastNode[lastLevel].add(hNode);
        } else {
          int prevLevel = level - 1;
          while (prevLevel >= 0) {
            if (lastNode[prevLevel] != null) {
              break;
            }
            lastNode[prevLevel] = null;
            prevLevel--;
          }
          lastNode[prevLevel].add(hNode);
        }
        lastNode[level] = hNode;
        lastLevel = level;
      }
    }
    return rootNode;
  }

  public Heading getNextHeading(Document doc, ElementIterator iter) {
    Element elem;

    while ((elem = iter.next()) != null) {
      AttributeSet attrs = elem.getAttributes();
      Object type = attrs.getAttribute(StyleConstants.NameAttribute);
      int level = getHeadingLevel(type);
      if (level > 0) {
        // It is a heading - get the text
        String headingText = "";
        int count = elem.getElementCount();
        for (int i = 0; i < count; i++) {
          Element child = elem.getElement(i);
          AttributeSet cattrs = child.getAttributes();
          if (cattrs.getAttribute(StyleConstants.NameAttribute) == HTML.Tag.CONTENT) {
            try {
              int offset = child.getStartOffset();
              headingText += doc.getText(offset, child
                  .getEndOffset()
                  - offset);
            } catch (BadLocationException e) {
            }
          }
        }
        headingText = headingText.trim();
        return new Heading(headingText, level, elem.getStartOffset());
      }
    }
    return null;
  }

  public int getHeadingLevel(Object type) {
    if (type instanceof HTML.Tag) {
      if (type == HTML.Tag.H1) {
        return 1;
      }
      if (type == HTML.Tag.H2) {
        return 2;
      }
      if (type == HTML.Tag.H3) {
        return 3;
      }
      if (type == HTML.Tag.H4) {
        return 4;
      }
      if (type == HTML.Tag.H5) {
        return 5;
      }
      if (type == HTML.Tag.H6) {
        return 6;
      }
    }

    return -1;
  }

  static class Heading {
    public Heading(String text, int level, int offset) {
      this.text = text;
      this.level = level;
      this.offset = offset;
    }

    public String getText() {
      return text;
    }

    public int getOffset() {
      return offset;
    }

    public int getLevel() {
      return level;
    }

    public String toString() {
      return text;
    }

    protected String text;

    protected int level;

    protected int offset;
  }

  public static void main(String[] args) {
    try {
        UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
    } catch (Exception evt) {}
  
    JFrame f = new EditorPaneExample14();

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

  private static final String spaces = "                    ";

  private static final String LOAD_TIME = "Load time: ";

  private HTMLDocumentLoader loader;

  private JEditorPane pane;

  private JLabel loadingState;

  private JLabel loadedType;

  private JLabel timeLabel;

  private JComboBox urlCombo;

  private JCheckBox onlineLoad;

  private JTree tree;

  private TreeModel emptyModel;

  private long startTime;

  private boolean populatingCombo;

  private boolean loadingPage;

  private final Cursor waitCursor = Cursor
      .getPredefinedCursor(Cursor.WAIT_CURSOR);

  private static final Cursor defaultCursor = Cursor
      .getPredefinedCursor(Cursor.DEFAULT_CURSOR);

  private static final Cursor handCursor = Cursor
      .getPredefinedCursor(Cursor.HAND_CURSOR);

  private static final HTMLEditorKit editorKit = new HTMLEditorKit();
}

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();
  }
}

           
         
    
    
    
  








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