java.lang.IllegalStateException while using Document Listener in TextArea, Java
DocumentListener dl = new MessageDocumentListener();
((AbstractDocument) nboxArea.getDocument()).setDocumentFilter(new DocumentFilter() {
public void insertString(FilterBypass fb, int offset, String string, AttributeSet attr) throws BadLocationException {
string = string.replaceAll("\t", "");
super.insertString(fb, offset, string,(javax.swing.text.AttributeSet) attr);
}
public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {
text = text.replaceAll("\t", 开发者_开发问答"");
//TODO must do something here
super.replace(fb, offset, length, text,(javax.swing.text.AttributeSet) attrs);
}
});
JTextArea evArea = (JTextArea) c;
evArea.getDocument().removeDocumentListener(dl);
evArea.setText(originalMessage);
In this case I found the following error during set text in textarea. I do not know how to resolve.
Exception in thread "AWT-EventQueue-0"
java.lang.IllegalStateException: Attempt to mutate in notification
I think the problem is to set text in document or setting document in document listener. But I do not know how to solve this. Please help me to solve this issue.
You cannot modify the document inside the DocumentListener. Write a custom Document instead, which overrides the insertString() or remove() methods.
From Java Tutorials: How to write a DocumentListener
Document listeners should not modify the contents of the document; The change is already complete by the time the listener is notified of the change. Instead, write a custom document that overrides the insertString or remove methods, or both. See Listening for Changes on a Document for details.
If you want to mutate in the listener you can launch a separate thread to do it later with SwingUtilities.invokeLater. Be careful because the modifications from the separate thread will call the listener again, so set a boolean before launching the thread, return immediately from the listener if it is set and reset it after the modifications have been done in the separate thread.
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