Java clipboard is not shared with system

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I have an JEditorPane field formatted as HTML and when I’m copying it to clipboard the system is losing all the line breaks.

Text inside JEditorPane :

 <html>
  <head>
  </head>
  <body>
    <p>
      Bonjour,<br><br>Merci de faire les actions ci-dessous:<br><br>1- 
      Sauvegarder le fichier AAAA<br>2- Remplacer le contenu du 
      fichier AAAA par le contenu fichier 
      BBBBB <br>3- Relancer au step plant&#233;<br><br>Cordialement,<br>
    </p>
  </body>
</html>

When copying with Ctrl + C and paste it in Notepad++ the text is:

Bonjour,  Merci de faire les actions ci-dessous:  1- Sauvegarder le fichier AAAA 2- Remplacer le contenu du fichier AAAA par le contenu fichier BBBB 3- Relancer au step planté  Cordialement, 

So, I’ve intercepted the Ctrl+C:

public void keyPressed(KeyEvent e) {
//Modify clipboard Ctrl+C
if ((e.getKeyCode() == KeyEvent.VK_C) && ((e.getModifiers() & KeyEvent.CTRL_MASK) != 0)) {
super.keyPressed(e);
genericFunctions.setClipboardText(edSolution.getText());//see function bellow
}

And I’ve tried do modify it:

static void setClipboardText(String s) {
  Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
  StringSelection stringSelection = new StringSelection(s);
  clipboard.setContents(stringSelection, stringSelection);
}

but the text inside clipboard is not changing.

The strange thing is that if I’m using this function bellow:

 static void setClipboardText(String s) {
    Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
    Clipboard selection = Toolkit.getDefaultToolkit().getSystemSelection();
    StringSelection stringSelection = new StringSelection(s);
    StringSelection stringS = new StringSelection(s);
    clipboard.setContents(stringSelection, stringSelection);
    selection.setContents(stringS, stringS);//error AWT-EventQueue-0" java.lang.NullPointerException"
}

even though I’m getting a NullPointerException, the clipboard is well modified with the new value.

Can someone tell me why the clipboard is only refreshed after the error and not before ? How can I announce the System that the clipboard was changed and should read it ?

JDK8 v1.8.0_251

Answer

I going to surmise that the “default” copy operation only copies the text from the editor as “plain text” – or at least, that is one of the options available to the receiver and it’s taking it as a preference (I don’t have easy access to the Java Source to go digging into the default implementation)

As outlined in Copy JTextArea as “text/html” DataFlavor and Copy jTable row with its grid lines into excel/word documents you can override the default “copy” action and insert your own workflow/formatting.

This is a VERY simple example of the concept. When I copy and paste text using this, I get the complete HTML text.

If you’d prefer not simply get the text with line breaks, you’d have to interpret the content yourself and generate a suitable output String, you could then use DataFlavor.stringFlavor as the primary data flavour, but is getting beyond the scope.

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.event.ActionEvent;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringBufferInputStream;
import java.io.StringReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import javax.swing.AbstractAction;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private JEditorPane editorPane;

        public TestPane() {

            URL url = getClass().getResource("Text.html");
            editorPane = new JEditorPane();
            editorPane.setContentType("html/text");
            try {
                editorPane.setPage(url);
            } catch (IOException ex) {
                ex.printStackTrace();
            }
            editorPane.getActionMap().put("copy", new AbstractAction() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    String text = editorPane.getText();
                    Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
                    clipboard.setContents(new HtmlSelection(text), null);
                }
            });
            setLayout(new BorderLayout());
            add(new JScrollPane(editorPane));
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }
    }

    private static class HtmlSelection implements Transferable {

        private static List<DataFlavor> htmlFlavors = new ArrayList<>(3);

        static {

            try {
                htmlFlavors.add(new DataFlavor("text/html;class=java.lang.String"));
                htmlFlavors.add(new DataFlavor("text/html;class=java.io.Reader"));
                htmlFlavors.add(new DataFlavor("text/html;charset=unicode;class=java.io.InputStream"));
            } catch (ClassNotFoundException ex) {
                ex.printStackTrace();
            }

        }

        private String html;

        public HtmlSelection(String html) {
            this.html = html;
        }

        public DataFlavor[] getTransferDataFlavors() {
            return (DataFlavor[]) htmlFlavors.toArray(new DataFlavor[htmlFlavors.size()]);
        }

        public boolean isDataFlavorSupported(DataFlavor flavor) {
            return htmlFlavors.contains(flavor);
        }

        public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException {
            if (String.class.equals(flavor.getRepresentationClass())) {
                return html;
            } else if (Reader.class.equals(flavor.getRepresentationClass())) {
                return new StringReader(html);
            } else if (InputStream.class.equals(flavor.getRepresentationClass())) {
                return new StringBufferInputStream(html);
            }
            throw new UnsupportedFlavorException(flavor);
        }
    }
}

Updated

Okay, so after some digging around, I found the JEditorPane is using the default functionality from JTextComponent to copy the contents of the Document to the clipboard…

public void exportToClipboard(JComponent comp, Clipboard clipboard,
                              int action) throws IllegalStateException {
    if (comp instanceof JTextComponent) {
        JTextComponent text = (JTextComponent)comp;
        int p0 = text.getSelectionStart();
        int p1 = text.getSelectionEnd();
        if (p0 != p1) {
            try {
                Document doc = text.getDocument();
                String srcData = doc.getText(p0, p1 - p0);
                StringSelection contents =new StringSelection(srcData);

                // this may throw an IllegalStateException,
                // but it will be caught and handled in the
                // action that invoked this method
                clipboard.setContents(contents, null);

                if (action == TransferHandler.MOVE) {
                    doc.remove(p0, p1 - p0);
                }
            } catch (BadLocationException ble) {}
        }
    }
}

The problem with this is, it’s not taking into account, the styled markup. Joy.

So, after a bit more reading, I came across – Copying to the clipboard in Java

So, I modified the original code to make use of the same concept to this…

editorPane.getActionMap().put("copy", new AbstractAction() {
    @Override
    public void actionPerformed(ActionEvent e) {
        String text = editorPane.getText();
        text = formattedPlainText(text);
        StringSelection selection = new StringSelection(text);
        Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
        clipboard.setContents(selection, selection);
    }

    protected String formattedPlainText(String text) {
        final StringBuilder sb = new StringBuilder();
        HTMLEditorKit.ParserCallback parserCallback = new HTMLEditorKit.ParserCallback() {
            public boolean readyForNewline;

            @Override
            public void handleText(final char[] data, final int pos) {
                String s = new String(data);
                sb.append(s.trim());
                readyForNewline = true;
            }

            @Override
            public void handleStartTag(final HTML.Tag t, final MutableAttributeSet a, final int pos) {
                if (readyForNewline && (t == HTML.Tag.DIV || t == HTML.Tag.BR || t == HTML.Tag.P)) {
                    sb.append("n");
                    readyForNewline = false;
                }
            }

            @Override
            public void handleSimpleTag(final HTML.Tag t, final MutableAttributeSet a, final int pos) {
                handleStartTag(t, a, pos);
            }
        };
        try {
            new ParserDelegator().parse(new StringReader(text), parserCallback, false);
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        
        return sb.toString();
    }
});

And I can now when I copy the text I get this…

Bonjour,
Merci de faire les actions ci-dessous:
1- Sauvegarder le fichier AAAA
2- Remplacer le contenu du fichier AAAA par le contenu fichier BBBBB
3- Relancer au step planté
Cordialement,

Cavet

Both examples will ignore the selection and will copy the whole text – this is a limitation of my time. If required, it would take more effort to extract the styled markup from the StyledDocument and make determinations about how best to format the text



Source: stackoverflow