public  void actionPerformed(ActionEvent e) 
{
            if (width == 0 || height == 0) {
                // setVisible(true) will cause a scroll, only do this if the
                // new location is really valid.
                if (component != null) {
                    TextUI mapper = component.getUI();
                    try {
                        Rectangle r = mapper.modelToView(component, dot,
                                                         dotBias);
                        if (r != null && r.width != 0 && r.height != 0) {
                            damage(r);
                        }
                    } catch (BadLocationException ble) {
                    }
                }
            }
            visible = !visible;
            repaint();
}

Invoked when the blink timer fires. This is called asynchronously. The simply changes the visibility and repaints the rectangle that last bounded the caret.

 public  void changedUpdate(DocumentEvent e) 
{
            if (getUpdatePolicy() == NEVER_UPDATE ||
                    (getUpdatePolicy() == UPDATE_WHEN_ON_EDT &&
                    !SwingUtilities.isEventDispatchThread())) {
                return;
            }
            if(e instanceof AbstractDocument.UndoRedoDocumentEvent) {
                setDot(e.getOffset() + e.getLength());
            }
}

Gives notification that an attribute or set of attributes changed.

 public  void insertUpdate(DocumentEvent e) 
{
            if (getUpdatePolicy() == NEVER_UPDATE ||
                    (getUpdatePolicy() == UPDATE_WHEN_ON_EDT &&
                    !SwingUtilities.isEventDispatchThread())) {
                if ((e.getOffset() < = dot || e.getOffset() < = mark)
                        && selectionTag != null) {
                    try {
                        component.getHighlighter().changeHighlight(selectionTag,
                                Math.min(dot, mark), Math.max(dot, mark));
                    } catch (BadLocationException e1) {
                        e1.printStackTrace();
                    }
                }
                return;
            }
            int adjust = 0;
            int offset = e.getOffset();
            int length = e.getLength();
            int newDot = dot;
            short changed = 0;
            if (e instanceof AbstractDocument.UndoRedoDocumentEvent) {
                setDot(offset + length);
                return;
            }
            if (newDot  >= offset) {
                newDot += length;
                changed |= 1;
            }
            int newMark = mark;
            if (newMark  >= offset) {
                newMark += length;
                changed |= 2;
            }
            if (changed != 0) {
                Position.Bias dotBias = DefaultCaret.this.dotBias;
                if (dot == offset) {
                    Document doc = component.getDocument();
                    boolean isNewline;
                    try {
                        Segment s = new Segment();
                        doc.getText(newDot - 1, 1, s);
                        isNewline = (s.count  > 0 &&
                                s.array[s.offset] == '\n");
                    } catch (BadLocationException ble) {
                        isNewline = false;
                    }
                    if (isNewline) {
                        dotBias = Position.Bias.Forward;
                    } else {
                        dotBias = Position.Bias.Backward;
                    }
                }
                if (newMark == newDot) {
                    setDot(newDot, dotBias);
                    ensureValidPosition();
                }
                else {
                    setDot(newMark, markBias);
                    if (getDot() == newMark) {
                        // Due this test in case the filter vetoed the
                        // change in which case this probably won't be
                        // valid either.
                        moveDot(newDot, dotBias);
                    }
                    ensureValidPosition();
                }
            }
}

Updates the dot and mark if they were changed by the insertion.

 public  void lostOwnership(Clipboard clipboard,
    Transferable contents) 
{
            if (ownsSelection) {
                ownsSelection = false;
                if (component != null && !component.hasFocus()) {
                    setSelectionVisible(false);
                }
            }
}

Toggles the visibility of the selection when ownership is lost.

 public  void propertyChange(PropertyChangeEvent evt) 
{
            Object oldValue = evt.getOldValue();
            Object newValue = evt.getNewValue();
            if ((oldValue instanceof Document) || (newValue instanceof Document)) {
                setDot(0);
                if (oldValue != null) {
                    ((Document)oldValue).removeDocumentListener(this);
                }
                if (newValue != null) {
                    ((Document)newValue).addDocumentListener(this);
                }
            } else if("enabled".equals(evt.getPropertyName())) {
                Boolean enabled = (Boolean) evt.getNewValue();
                if(component.isFocusOwner()) {
                    if(enabled == Boolean.TRUE) {
                        if(component.isEditable()) {
                            setVisible(true);
                        }
                        setSelectionVisible(true);
                    } else {
                        setVisible(false);
                        setSelectionVisible(false);
                    }
                }
            } else if("caretWidth".equals(evt.getPropertyName())) {
                Integer newWidth = (Integer) evt.getNewValue();
                if (newWidth != null) {
                    caretWidth = newWidth.intValue();
                } else {
                    caretWidth = -1;
                }
                repaint();
            } else if("caretAspectRatio".equals(evt.getPropertyName())) {
                Number newRatio = (Number) evt.getNewValue();
                if (newRatio != null) {
                    aspectRatio = newRatio.floatValue();
                } else {
                    aspectRatio = -1;
                }
                repaint();
            }
}

This method gets called when a bound property is changed. We are looking for document changes on the editor.

 public  void removeUpdate(DocumentEvent e) 
{
            if (getUpdatePolicy() == NEVER_UPDATE ||
                    (getUpdatePolicy() == UPDATE_WHEN_ON_EDT &&
                    !SwingUtilities.isEventDispatchThread())) {
                int length = component.getDocument().getLength();
                dot = Math.min(dot, length);
                mark = Math.min(mark, length);
                if ((e.getOffset() <  dot || e.getOffset() <  mark)
                        && selectionTag != null) {
                    try {
                        component.getHighlighter().changeHighlight(selectionTag,
                                Math.min(dot, mark), Math.max(dot, mark));
                    } catch (BadLocationException e1) {
                        e1.printStackTrace();
                    }
                }
                return;
            }
            int offs0 = e.getOffset();
            int offs1 = offs0 + e.getLength();
            int adjust = 0;
            int newDot = dot;
            boolean adjustDotBias = false;
            int newMark = mark;
            boolean adjustMarkBias = false;
            if(e instanceof AbstractDocument.UndoRedoDocumentEvent) {
                setDot(offs0);
                return;
            }
            if (newDot  >= offs1) {
                newDot -= (offs1 - offs0);
                if(newDot == offs1) {
                    adjustDotBias = true;
                }
            } else if (newDot  >= offs0) {
                newDot = offs0;
                adjustDotBias = true;
            }
            if (newMark  >= offs1) {
                newMark -= (offs1 - offs0);
                if(newMark == offs1) {
                    adjustMarkBias = true;
                }
            } else if (newMark  >= offs0) {
                newMark = offs0;
                adjustMarkBias = true;
            }
            if (newMark == newDot) {
                forceCaretPositionChange = true;
                try {
                    setDot(newDot, guessBiasForOffset(newDot, dotBias,
                            dotLTR));
                } finally {
                    forceCaretPositionChange = false;
                }
                ensureValidPosition();
            } else {
                Position.Bias dotBias = DefaultCaret.this.dotBias;
                Position.Bias markBias = DefaultCaret.this.markBias;
                if(adjustDotBias) {
                    dotBias = guessBiasForOffset(newDot, dotBias, dotLTR);
                }
                if(adjustMarkBias) {
                    markBias = guessBiasForOffset(mark, markBias, markLTR);
                }
                setDot(newMark, markBias);
                if (getDot() == newMark) {
                    // Due this test in case the filter vetoed the change
                    // in which case this probably won't be valid either.
                    moveDot(newDot, dotBias);
                }
                ensureValidPosition();
            }
}

Updates the dot and mark if they were changed by the removal.