Class StateEdit

java.lang.Object
javax.swing.undo.AbstractUndoableEdit
javax.swing.undo.StateEdit
All Implemented Interfaces:
Serializable, UndoableEdit
public class StateEdit extends AbstractUndoableEdit

StateEdit is a general edit for objects that change state. Objects being edited must conform to the StateEditable interface.

This edit class works by asking an object to store it's state in Hashtables before and after editing occurs. Upon undo or redo the object is told to restore it's state from these Hashtables.

A state edit is used as follows: 
     // Create the edit during the "before" state of the object
     StateEdit newEdit = new StateEdit(myObject);
     // Modify the object
     myObject.someStateModifyingMethod();
     // "end" the edit when you are done modifying the object
     newEdit.end();

Note that when a StateEdit ends, it removes redundant state from the Hashtables - A state Hashtable is not guaranteed to contain all keys/values placed into it when the state is stored!

See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected StateEditable
    object
    The object being edited
    protected Hashtable<Object,Object>
    postState
    The state information after the edit
    protected Hashtable<Object,Object>
    preState
    The state information prior to the edit
    protected static final String
    RCSID
    Obsolete RCS version identity.
    protected String
    undoRedoName
    The undo/redo presentation name

    Fields declared in class AbstractUndoableEdit

    RedoName, UndoName
    Modifier and Type
    Field
    Description
    protected static final String
    RedoName
    String returned by getRedoPresentationName; as of Java 2 platform v1.3.1 this field is no longer used.
    protected static final String
    UndoName
    String returned by getUndoPresentationName; as of Java 2 platform v1.3.1 this field is no longer used.

  • Constructor Summary

    Constructors
    Constructor
    Description
    StateEdit(StateEditable anObject)
    Create and return a new StateEdit.
    StateEdit(StateEditable anObject, String name)
    Create and return a new StateEdit with a presentation name.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    end()
    Gets the post-edit state of the StateEditable object and ends the edit.
    String
    getPresentationName()
    Gets the presentation name for this edit
    protected void
    init(StateEditable anObject, String name)
    Initialize the state edit.
    void
    redo()
    Tells the edited object to apply the state after the edit
    protected void
    removeRedundantState()
    Remove redundant key/values in state hashtables.
    void
    undo()
    Tells the edited object to apply the state prior to the edit

    Methods declared in class AbstractUndoableEdit

    addEdit, canRedo, canUndo, die, getRedoPresentationName, getUndoPresentationName, isSignificant, replaceEdit, toString
    Modifier and Type
    Method
    Description
    boolean
    addEdit(UndoableEdit anEdit)
    This default implementation returns false.
    boolean
    canRedo()
    Returns true if this edit is alive and hasBeenDone is false.
    boolean
    canUndo()
    Returns true if this edit is alive and hasBeenDone is true.
    void
    die()
    Sets alive to false.
    String
    getRedoPresentationName()
    Retrieves the value from the defaults table with key AbstractUndoableEdit.redoText and returns that value followed by a space, followed by getPresentationName.
    String
    getUndoPresentationName()
    Retrieves the value from the defaults table with key AbstractUndoableEdit.undoText and returns that value followed by a space, followed by getPresentationName.
    boolean
    isSignificant()
    This default implementation returns true.
    boolean
    replaceEdit(UndoableEdit anEdit)
    This default implementation returns false.
    String
    toString()
    Returns a string that displays and identifies this object's properties.

    Methods declared in class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    Modifier and Type
    Method
    Description
    protected Object
    clone()
    Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
    boolean
    equals(Object o)
    Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
    protected void
    finalize()
    Deprecated, for removal: This API element is subject to removal in a future version.
    May cause performance issues, deadlocks and hangs.
    final Class<? extends Object>
    getClass()
    Answers the unique instance of java.lang.Class which represents the class of the receiver.
    int
    hashCode()
    Answers an integer hash code for the receiver.
    final void
    notify()
    Causes one thread which is waiting on the receiver to be made ready to run.
    final void
    notifyAll()
    Causes all threads which are waiting on the receiver to be made ready to run.
    final void
    wait()
    Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
    final void
    wait(long time)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
    final void
    wait(long time, int frac)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.