javax.swing.undo

Class CompoundEdit

java.lang.Object

javax.swing.undo.AbstractUndoableEdit

javax.swing.undo.CompoundEdit

All Implemented Interfaces:

Serializable, UndoableEdit

Direct Known Subclasses:

AbstractDocument.DefaultDocumentEvent, UndoManager

public class CompoundEdit
extends AbstractUndoableEdit

An editing action that consists of multiple UndoableEdits.

The use of a CompoundEdit is divided in two separate phases.

1. In the first phase, the CompoundEdit is initialized. After a new instance of CompoundEdit has been created, addEdit(UndoableEdit) is called for each element of the compound. To terminate the initialization phase, call end().
2. In the second phase, the the CompoundEdit can be used, typically by invoking undo() and redo().

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected Vector<UndoableEdit>	edits The UndoableEdits being combined into a compound editing action.

Fields inherited from class javax.swing.undo.AbstractUndoableEdit

RedoName, UndoName

Constructor Summary

Constructors

Constructor and Description
CompoundEdit() Constructs a new CompoundEdit.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	addEdit(UndoableEdit edit) Incorporates another editing action into this one, thus forming a combined edit.
boolean	canRedo() Determines whether it would be possible to redo this editing action.
boolean	canUndo() Determines whether it would be possible to undo this editing action.
void	die() Informs this edit action, and all compound edits, that they will no longer be used.
void	end() Informs this CompoundEdit that its construction phase has been completed.
String	getPresentationName() Returns a human-readable, localized name that describes this editing action and can be displayed to the user.
String	getRedoPresentationName() Calculates a localized message text for presenting the redo action to the user.
String	getUndoPresentationName() Calculates a localized message text for presenting the undo action to the user.
boolean	isInProgress() Determines whether the initial construction phase of this CompoundEdit is still in progress.
boolean	isSignificant() Determines whether this editing action is significant enough for being seperately undoable by the user.
protected UndoableEdit	lastEdit() Returns the the UndoableEdit that was last added to this compound.
void	redo() Redoes all edits that are part of of this CompoundEdit.
String	toString() Calculates a string that may be useful for debugging.
void	undo() Undoes all edits that are part of of this CompoundEdit.

Methods inherited from class javax.swing.undo.AbstractUndoableEdit

replaceEdit

Methods inherited from class java.lang.Object

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

Field Detail

edits

protected Vector<UndoableEdit> edits

The UndoableEdits being combined into a compound editing action.

Constructor Detail

CompoundEdit

public CompoundEdit()

Constructs a new CompoundEdit.

Method Detail

undo

public void undo()
          throws CannotUndoException

Undoes all edits that are part of of this CompoundEdit. The compound elements will receive the undo message in the reverse order of addition.

Specified by:

undo in interface UndoableEdit

Overrides:

undo in class AbstractUndoableEdit

Throws:

CannotUndoException - if canUndo() returns false. This can happen if end() has not been called on this CompoundEdit, or if this edit has already been undone.

See Also:

canUndo(), redo()

redo

public void redo()
          throws CannotRedoException

Redoes all edits that are part of of this CompoundEdit. The compound elements will receive the undo message in the same order as they were added.

Specified by:

redo in interface UndoableEdit

Overrides:

redo in class AbstractUndoableEdit

Throws:

CannotRedoException - if canRedo() returns false. This can happen if end() has not been called on this CompoundEdit, or if this edit has already been redone.

See Also:

canRedo(), undo()

lastEdit

protected UndoableEdit lastEdit()

Returns the the UndoableEdit that was last added to this compound.

die

public void die()

Informs this edit action, and all compound edits, that they will no longer be used. Some actions might use this information to release resources such as open files. Called by UndoManager before this action is removed from the edit queue.

The compound elements will receive the die message in the reverse order of addition.

Specified by:

die in interface UndoableEdit

Overrides:

die in class AbstractUndoableEdit

addEdit

public boolean addEdit(UndoableEdit edit)

Incorporates another editing action into this one, thus forming a combined edit.

If this edit’s end() method has been called before, false is returned immediately. Otherwise, the last added edit is given the opportunity to incorporate edit. If this fails, edit is given the opportunity to replace the last added edit. If this fails as well, edit gets added as a new compound to edits.

Specified by:

addEdit in interface UndoableEdit

Overrides:

addEdit in class AbstractUndoableEdit

Parameters:

edit - the editing action being added.

Returns:

true if edit could somehow be incorporated; false if edit has not been incorporated because end() was called before.

end

public void end()

Informs this CompoundEdit that its construction phase has been completed. After this method has been called, undo() and redo() may be called, isInProgress() will return false, and all attempts to add further edits will fail.

canUndo

public boolean canUndo()

Determines whether it would be possible to undo this editing action. The result will be true if end() has been called on this CompoundEdit, die() has not yet been called, and the edit has not been undone already.

Specified by:

canUndo in interface UndoableEdit

Overrides:

canUndo in class AbstractUndoableEdit

Returns:

true to indicate that this action can be undone; false otherwise.

See Also:

undo(), canRedo()

canRedo

public boolean canRedo()

Determines whether it would be possible to redo this editing action. The result will be true if end() has been called on this CompoundEdit, die() has not yet been called, and the edit has not been redone already.

Specified by:

canRedo in interface UndoableEdit

Overrides:

canRedo in class AbstractUndoableEdit

Returns:

true to indicate that this action can be redone; false otherwise.

See Also:

redo(), canUndo()

isInProgress

public boolean isInProgress()

Determines whether the initial construction phase of this CompoundEdit is still in progress. During this phase, edits may be added. After initialization has been terminated by calling end(), undo() and redo() can be used.

Returns:

true if the initialization phase is still in progress; false if end() has been called.

See Also:

end()

isSignificant

public boolean isSignificant()

Determines whether this editing action is significant enough for being seperately undoable by the user. A typical significant action would be the resizing of an object. However, changing the selection in a text document would usually not be considered significant.

A CompoundEdit is significant if any of its elements are significant.

Specified by:

isSignificant in interface UndoableEdit

Overrides:

isSignificant in class AbstractUndoableEdit

Returns:

true to indicate that the action is significant enough for being separately undoable, or false otherwise.

getPresentationName

public String getPresentationName()

Returns a human-readable, localized name that describes this editing action and can be displayed to the user.

The implementation delegates the call to the last added edit action. If no edit has been added yet, the inherited implementation will be invoked, which always returns an empty string.

Specified by:

getPresentationName in interface UndoableEdit

Overrides:

getPresentationName in class AbstractUndoableEdit

Returns:

The presentation name.

getUndoPresentationName

public String getUndoPresentationName()

Calculates a localized message text for presenting the undo action to the user.

The implementation delegates the call to the last added edit action. If no edit has been added yet, the inherited implementation will be invoked.

Specified by:

getUndoPresentationName in interface UndoableEdit

Overrides:

getUndoPresentationName in class AbstractUndoableEdit

Returns:

The undo presentation name.

getRedoPresentationName

public String getRedoPresentationName()

Calculates a localized message text for presenting the redo action to the user.

The implementation delegates the call to the last added edit action. If no edit has been added yet, the inherited implementation will be invoked.

Specified by:

getRedoPresentationName in interface UndoableEdit

Overrides:

getRedoPresentationName in class AbstractUndoableEdit

Returns:

The redo presentation name.

toString

public String toString()

Calculates a string that may be useful for debugging.

Overrides:

toString in class AbstractUndoableEdit

Returns:

the String representing this Object, which may be null

See Also:

Object.getClass(), Object.hashCode(), Class.getName(), Integer.toHexString(int)