/**
* Накат истории вперед
*
* @param target Запись истории
* @param textPane Текст для которого применяется историческое изменение
*/
public static void applyForward(UndoTextAction target, JTextComponent textPane) {
if (target == null) throw new IllegalArgumentException("target==null");
if (textPane == null) throw new IllegalArgumentException("textPane==null");
try {
javax.swing.text.Document doc = textPane.getDocument();
int offset = target.getOffset();
String changes = target.getChangedText();
if (UndoTextAction.Action.Added.equals(target.getAction())) {
doc.insertString(offset, changes, null);
int L = doc.getLength();
int P = offset + changes.length();
if (P > L) P = L;
textPane.setCaretPosition(P);
} else if (UndoTextAction.Action.Deleted.equals(target.getAction())) {
doc.remove(offset, changes.length());
textPane.setCaretPosition(offset);
}
} catch (BadLocationException ex) {
Logger.getLogger(UndoTextAction.class.getName()).log(Level.SEVERE, null, ex);
}
}
/**
* Откат истории назад
*
* @param target Запись истории
* @param snapshot Текст для которого применяется историческое изменение
* @return Текст модифицированный записью
*/
public static String applyBack(UndoTextAction target, String snapshot) {
if (target == null) throw new IllegalArgumentException("target==null");
if (snapshot == null) throw new IllegalArgumentException("snapshot==null");
String text = snapshot;
int offset = target.getOffset();
int textLen = text.length();
String changes = target.getChangedText();
String before = null;
String after = null;
String res = null;
if (UndoTextAction.Action.Added.equals(target.getAction())) {
StringBuilder sb = new StringBuilder();
before = (offset > 0 && offset <= textLen) ? text.substring(0, offset) : "";
int cutOffset = offset + changes.length();
after = (cutOffset > 0 && cutOffset <= textLen) ? text.substring(cutOffset) : "";
sb.append(before);
sb.append(after);
res = sb.toString();
} else if (UndoTextAction.Action.Deleted.equals(target.getAction())) {
StringBuilder sb = new StringBuilder();
before = (offset > 0 && offset <= textLen) ? text.substring(0, offset) : "";
after = (offset > 0 && offset <= textLen) ? text.substring(offset) : "";
sb.append(before);
sb.append(changes);
sb.append(after);
res = sb.toString();
}
return res;
}