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Class com.sun.java.swing.undo.UndoManager

java.lang.Object
  |
  +--com.sun.java.swing.undo.AbstractUndoableEdit
        |
        +--com.sun.java.swing.undo.CompoundEdit
              |
              +--com.sun.java.swing.undo.UndoManager

public class UndoManager

extends CompoundEdit

implements UndoableEditListener

Concrete subclass of CompoundEdit which can serve as an UndoableEditListener, consolidating the UndoableEditEvents from a variety of sources, and undoing or redoing them one at a time. Unlike AbstractUndoableEdit and CompoundEdit, the public methods of this class are synchronized, and should be safe to call from multiple threads. This should make UndoManager a convenient marshall for sets of undoable JavaBeans.

Warning: serialized objects of this class will not be compatible with future swing releases. The current serialization support is appropriate for short term storage or RMI between Swing1.0 applications. It will not be possible to load serialized Swing1.0 objects with future releases of Swing. The JDK1.2 release of Swing will be the compatibility baseline for the serialized form of Swing objects.

Fields inherited from class com.sun.java.swing.undo.CompoundEdit

edits

Fields inherited from class com.sun.java.swing.undo.AbstractUndoableEdit

RedoName, UndoName

Constructor Summary

UndoManager()

Method Summary

boolean	addEdit(UndoableEdit anEdit) If inProgress, inserts anEdit at indexOfNextAdd, and removes any old edits that were at indexOfNextAdd or later.
boolean	canRedo() Overridden to preserve usual semantics: returns true if a redo operation would be successful now, false otherwise
boolean	canUndoOrRedo() Return true if calling undoOrRedo will undo or redo.
boolean	canUndo() Overridden to preserve usual semantics: returns true if an undo operation would be successful now, false otherwise
void	discardAllEdits() Empty the undo manager, sending each edit a die message in the process.
UndoableEdit	editToBeRedone() Returns the the next significant edit to be redone if redo is called.
UndoableEdit	editToBeUndone() Returns the the next significant edit to be undone if undo is called.
int	getLimit() Returns the maximum number of edits this UndoManager will hold.
java.lang.String	getRedoPresentationName() If inProgress, returns getRedoPresentationName of the significant edit that will be redone when redo() is invoked.
java.lang.String	getUndoOrRedoPresentationName() Return the appropriate name for a command that toggles between undo and redo.
java.lang.String	getUndoPresentationName() If inProgress, returns getUndoPresentationName of the significant edit that will be undone when undo() is invoked.
void	redoTo(UndoableEdit edit) Redoes all changes from indexOfNextAdd to edit.
void	redo() If this UndoManager is inProgress, redoes the last significant UndoableEdit at indexOfNextAdd or after, and all insignificant edits up to it.
void	setLimit(int l) Set the maximum number of edits this UndoManager will hold.
java.lang.String	toString()
void	trimEdits(int from, int to) Tell the edits in the given range (inclusive) to die, and remove them from edits. from > to is a no-op.
void	trimForLimit() Reduce the number of queued edits to a range of size limit, centered on indexOfNextAdd.
void	undoableEditHappened(UndoableEditEvent e) Called by the UndoabledEdit sources this UndoManager listens to.
void	undoOrRedo() Undo or redo as appropriate.
void	undoTo(UndoableEdit edit) Undoes all changes from indexOfNextAdd to edit.
void	undo() If this UndoManager is inProgress, undo the last significant UndoableEdit before indexOfNextAdd, and all insignificant edits back to it.

Methods inherited from class com.sun.java.swing.undo.CompoundEdit

addEdit, canRedo, canUndo, die, end, getPresentationName, getRedoPresentationName, getUndoPresentationName, isInProgress, isSignificant, lastEdit, redo, toString, undo

Methods inherited from class com.sun.java.swing.undo.AbstractUndoableEdit

addEdit, canRedo, canUndo, die, getPresentationName, getRedoPresentationName, getUndoPresentationName, isSignificant, redo, replaceEdit, toString, undo

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notifyAll, notify, toString, wait, wait, wait

Constructor Detail

UndoManager

public UndoManager()

Method Detail

getLimit

public int getLimit()

Returns the maximum number of edits this UndoManager will hold. Default value is 100.

See Also:

addEdit, setLimit

discardAllEdits

public void discardAllEdits()

Empty the undo manager, sending each edit a die message in the process.

trimForLimit

protected void trimForLimit()

Reduce the number of queued edits to a range of size limit, centered on indexOfNextAdd.

trimEdits

protected void trimEdits(int from,
                         int to)

Tell the edits in the given range (inclusive) to die, and remove them from edits. from > to is a no-op.

setLimit

public void setLimit(int l)

Set the maximum number of edits this UndoManager will hold. If edits need to be discarded to shrink the limit, they will be told to die in the reverse of the order that they were added.

See Also:

addEdit, getLimit

editToBeUndone

protected UndoableEdit editToBeUndone()

Returns the the next significant edit to be undone if undo is called. May return null

editToBeRedone

protected UndoableEdit editToBeRedone()

Returns the the next significant edit to be redone if redo is called. May return null

undoTo

protected void undoTo(UndoableEdit edit)
              throws CannotUndoException

Undoes all changes from indexOfNextAdd to edit. Updates indexOfNextAdd accordingly.

redoTo

protected void redoTo(UndoableEdit edit)
              throws CannotRedoException

Redoes all changes from indexOfNextAdd to edit. Updates indexOfNextAdd accordingly.

undoOrRedo

public void undoOrRedo()
               throws CannotRedoException,
                      CannotUndoException

Undo or redo as appropriate. Suitable for binding to an action that toggles between these two functions. Only makes sense to send this if limit == 1.

See Also:

canUndoOrRedo, getUndoOrRedoPresentationName

canUndoOrRedo

public boolean canUndoOrRedo()

Return true if calling undoOrRedo will undo or redo. Suitable for deciding to enable a command that toggles between the two functions, which only makes sense to use if limit == 1.

See Also:

undoOrRedo

undo

public void undo()
         throws CannotUndoException

If this UndoManager is inProgress, undo the last significant UndoableEdit before indexOfNextAdd, and all insignificant edits back to it. Updates indexOfNextAdd accordingly.

If not inProgress, indexOfNextAdd is ignored and super's routine is called.

Overrides:

undo in class CompoundEdit

See Also:

end

canUndo

public boolean canUndo()

Overridden to preserve usual semantics: returns true if an undo operation would be successful now, false otherwise

Overrides:

canUndo in class CompoundEdit

redo

public void redo()
         throws CannotRedoException

If this UndoManager is inProgress, redoes the last significant UndoableEdit at indexOfNextAdd or after, and all insignificant edits up to it. Updates indexOfNextAdd accordingly.

If not inProgress, indexOfNextAdd is ignored and super's routine is called.

Overrides:

redo in class CompoundEdit

See Also:

end

canRedo

public boolean canRedo()

Overridden to preserve usual semantics: returns true if a redo operation would be successful now, false otherwise

Overrides:

canRedo in class CompoundEdit

addEdit

public boolean addEdit(UndoableEdit anEdit)

If inProgress, inserts anEdit at indexOfNextAdd, and removes any old edits that were at indexOfNextAdd or later. The die method is called on each edit that is removed is sent, in the reverse of the order the edits were added. Updates indexOfNextAdd.

If not inProgress, acts as a CompoundEdit

Overrides:

addEdit in class CompoundEdit

See Also:

end, addEdit

getUndoOrRedoPresentationName

public java.lang.String getUndoOrRedoPresentationName()

Return the appropriate name for a command that toggles between undo and redo. Only makes sense to use such a command if limit == 1 and we're not in progress.

getUndoPresentationName

public java.lang.String getUndoPresentationName()

If inProgress, returns getUndoPresentationName of the significant edit that will be undone when undo() is invoked. If there is none, returns AbstractUndoableEdit.UndoName

If not inProgress, acts as a CompoundEdit

Overrides:

getUndoPresentationName in class CompoundEdit

See Also:

undo, getUndoPresentationName

getRedoPresentationName

public java.lang.String getRedoPresentationName()

If inProgress, returns getRedoPresentationName of the significant edit that will be redone when redo() is invoked. If there is none, returns AbstractUndoableEdit.RedoName

If not inProgress, acts as a CompoundEdit

Overrides:

getRedoPresentationName in class CompoundEdit

See Also:

redo, getUndoPresentationName

undoableEditHappened

public void undoableEditHappened(UndoableEditEvent e)

Called by the UndoabledEdit sources this UndoManager listens to. Calls addEdit with e.getEdit().

Specified by:

undoableEditHappened in interface UndoableEditListener

See Also:

addEdit

toString

public java.lang.String toString()

Overrides:

toString in class CompoundEdit