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Eclipse Platform
Release 3.5

org.eclipse.ltk.core.refactoring
Class CompositeChange

java.lang.Object
  extended by 

org.eclipse.ltk.core.refactoring.Change
      extended by 
org.eclipse.ltk.core.refactoring.CompositeChange
All Implemented Interfaces:
IAdaptable

public class CompositeChange
extends Change

Represents a composite change. Composite changes can be marked as synthetic. A synthetic composite changes might not be rendered in the refactoring preview tree to save display real-estate.

Clients may subclass this class.

Since:
3.0
See Also:
Change

Constructor Summary
CompositeChange ( String name)
          Creates a new composite change with the given name.
CompositeChange ( String name, Change[] children)
          Creates a new composite change with the given name and array of children.
 
Method Summary
 void add ( Change change)
          Adds the given change to the list of children.
 void addAll ( Change[] changes)
          Adds all changes in the given array to the list of children.
  Change[] clear ()
          Removes all changes from this composite change.
protected   Change createUndoChange ( Change[] childUndos)
          Hook to create an undo change.
 void dispose ()
          Disposes this change.
  Object[] getAffectedObjects ()
          Returns the elements affected by this change or null if the affected elements cannot be determined.
  Change[] getChildren ()
          Returns the children managed by this composite change.
  ChangeDescriptor getDescriptor ()
          Returns a descriptor of this change.
  Object getModifiedElement ()
          Returns the element modified by this Change.
  String getName ()
          Returns the human readable name of this change.
  Change getUndoUntilException ()
          Returns the undo object containing all undo changes of those children that got successfully executed while performing this change.
 void initializeValidationData ( IProgressMonitor pm)
          Hook method to initialize some internal state to provide an adequate answer for the isValid method.
protected  boolean internalContinueOnCancel ()
          Note: this is an internal method and should not be overridden outside of the refactoring framework.
protected  void internalHandleException ( Change change, Throwable t)
          Note: this is an internal method and should not be overridden outside of the refactoring framework.
protected  boolean internalProcessOnCancel ( Change change)
          Note: this is an internal method and should not be overridden outside of the refactoring framework.
 boolean isSynthetic ()
          Returns whether this change is synthetic or not.
  RefactoringStatus isValid ( IProgressMonitor pm)
          Verifies that this change object is still valid and can be executed by calling perform.
 void markAsSynthetic ()
          Marks this change as synthetic.
 void merge ( CompositeChange change)
          Merges the children of the given composite change into this change.
  Change perform ( IProgressMonitor pm)
          Performs this change.
 boolean remove ( Change change)
          Removes the given change from the list of children.
 void setEnabled (boolean enabled)
          Sets whether this change is enabled or not.
  String toString ()
           
 
Methods inherited from class org.eclipse.ltk.core.refactoring. Change
getAdapter, getParent, isEnabled, setEnabledShallow
 
Methods inherited from class java.lang. Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

CompositeChange

public CompositeChange(
String name)
Creates a new composite change with the given name.

Parameters:
name - the human readable name of the change. Will be used to display the change in the user interface

CompositeChange

public CompositeChange(
String name,
                       
Change[] children)
Creates a new composite change with the given name and array of children.

Parameters:
name - the human readable name of the change. Will be used to display the change in the user interface
children - the initial array of children
Method Detail

isSynthetic

public boolean isSynthetic()
Returns whether this change is synthetic or not.

Returns:
trueif this change is synthetic; otherwise false

markAsSynthetic

public void markAsSynthetic()
Marks this change as synthetic.


getName

public 
String getName()
Returns the human readable name of this change. The name MUST not be null.

Specified by:
getName in class Change
Returns:
the human readable name of this change

add

public void add(
Change change)
Adds the given change to the list of children. The change to be added can be null. Adding a "null" change does nothing.

Parameters:
change - the change to add

addAll

public void addAll(
Change[] changes)
Adds all changes in the given array to the list of children.

Parameters:
changes - the changes to add

merge

public void merge(
CompositeChange change)
Merges the children of the given composite change into this change. This means the changes are removed from the given composite change and added to this change.

Parameters:
change - the change to merge

remove

public boolean remove(
Change change)
Removes the given change from the list of children.

Parameters:
change - the change to remove
Returns:
true if the change contained the given child; otherwise false is returned

clear

public 
Change[] clear()
Removes all changes from this composite change.

Returns:
the list of changes removed from this composite change
Since:
3.1

getChildren

public 
Change[] getChildren()
Returns the children managed by this composite change.

Returns:
the children of this change or an empty array if no children exist

setEnabled

public void setEnabled(boolean enabled)
Sets whether this change is enabled or not.

The composite change sends setEnabled to all its children.

Client are allowed to extend this method.

Overrides:
setEnabled in class Change
Parameters:
enabled - true to enable this change; false otherwise

initializeValidationData

public void initializeValidationData(
IProgressMonitor pm)
Hook method to initialize some internal state to provide an adequate answer for the isValid method. This method gets called after a change or a whole change tree has been created.

Typically this method is implemented in one of the following ways:

  • the change hooks up a listener on some delta notification mechanism and marks itself as invalid if it receives a certain delta. Is this the case the implementor must take care of unhooking the listener in dispose.
  • the change remembers some information allowing to decide if a change object is still valid when isValid is called.

For example, a change object that manipulates the content of an IFile could either listen to resource changes and detect that the file got changed or it could remember some content stamp and compare it with the actual content stamp when isValid is called.

The composite change sends initializeValidationData to all its children.

Client are allowed to extend this method.

Specified by:
initializeValidationData in class Change
Parameters:
pm - a progress monitor

isValid

public 
RefactoringStatus isValid(
IProgressMonitor pm)
                          throws 
CoreException
Verifies that this change object is still valid and can be executed by calling perform. If a refactoring status with a severity of RefactoringStatus.FATAL is returned then the change has to be treated as invalid and can no longer be executed. Performing such a change produces an unspecified result and will very likely throw an exception.

This method is also called by the UndoManager to decide if an undo or redo change is still valid and therefore can be executed.

The composite change sends isValid to all its children until the first one returns a status with a severity of FATAL . If one of the children throws an exception the remaining children will not receive the isValid call.

Client are allowed to extend this method.

Specified by:
isValid in class Change
Parameters:
pm - a progress monitor.
Returns:
a refactoring status describing the outcome of the validation check
Throws:
CoreException - if an error occurred during validation check. The change is to be treated as invalid if an exception occurs

perform

public 
Change perform(
IProgressMonitor pm)
               throws 
CoreException
Performs this change. If this method is called on an invalid or disabled change object the result is unspecified. Changes should in general not respond to IProgressMonitor.isCanceled() since canceling a change tree in the middle of its execution leaves the workspace in a half changed state.

The composite change sends perform to all its enabled children. If one of the children throws an exception the remaining children will not receive the perform call. In this case the method getUndoUntilException can be used to get an undo object containing the undo objects of all executed children.

Client are allowed to extend this method.

Specified by:
perform in class Change
Parameters:
pm - a progress monitor
Returns:
the undo change for this change object or null if no undo is provided
Throws:
CoreException - if an error occurred during change execution

internalHandleException

protected void internalHandleException(
Change change,
                                       
Throwable t)
Note: this is an internal method and should not be overridden outside of the refactoring framework.

The method gets called if one of the changes managed by this composite change generates an exception when performed.

Parameters:
change - the change that caused the exception
t - the exception itself
Restriction:
This method is not intended to be referenced by clients.

internalContinueOnCancel

protected boolean internalContinueOnCancel()
Note: this is an internal method and should not be overridden outside of the refactoring framework.

The method gets called if one of the changes managed by this composite change generates an operation canceled exception when performed.

Returns:
true if performing the change should continue on cancel; otherwise false
Since:
3.1
Restriction:
This method is not intended to be referenced by clients.

internalProcessOnCancel

protected boolean internalProcessOnCancel(
Change change)
Note: this is an internal method and should not be overridden outside of the refactoring framework.

The method gets called if the execution of this change got canceled, but internalContinueOnCancel returned true.

Parameters:
change - the change to perform
Returns:
true if the given change should be performed although the execution got canceled; otherwise false
Since:
3.1
Restriction:
This method is not intended to be referenced by clients.

dispose

public void dispose()
Disposes this change. Subclasses that override this method typically unregister listeners which got registered during the call to initializeValidationState.

Subclasses may override this method.

The composite change sends dispose to all its children. It is guaranteed that all children receive the dispose call.

Overrides:
dispose in class Change

getUndoUntilException

public 
Change getUndoUntilException()
Returns the undo object containing all undo changes of those children that got successfully executed while performing this change. Returns null if all changes were executed successfully.

This method is not intended to be overridden or extended.

Returns:
the undo object containing all undo changes of those children that got successfully executed while performing this change

createUndoChange

protected 
Change createUndoChange(
Change[] childUndos)
Hook to create an undo change. The method should be overridden by clients which provide their own composite change to create a corresponding undo change.

Parameters:
childUndos - the child undo. The undo edits appear in the list in the reverse order of their execution. So the first change in the array is the undo change of the last change that got executed.
Returns:
the undo change

getAffectedObjects

public 
Object[] getAffectedObjects()
Returns the elements affected by this change or null if the affected elements cannot be determined. Returns an empty array if the change doesn't modify any elements.

This default implementation returns null to indicate that the affected elements are unknown. Subclasses should reimplement this method if they can compute the set of affected elements.

Overrides:
getAffectedObjects in class Change
Returns:
the elements affected by this change or null if the affected elements cannot be determined

getModifiedElement

public 
Object getModifiedElement()
Returns the element modified by this Change. The method may return null if the change isn't related to an element.

Specified by:
getModifiedElement in class Change
Returns:
the element modified by this change

getDescriptor

public 
ChangeDescriptor getDescriptor()
Returns a descriptor of this change.

Subclasses of changes created by Refactoring.createChange(IProgressMonitor) should override this method to return a RefactoringChangeDescriptor. A change tree created by a particular refactoring is supposed to contain at most one change which returns a refactoring descriptor. Refactorings usually return an instance of CompositeChange in their Refactoring.createChange(IProgressMonitor) method which implements this method. The refactoring framework searches the change tree top-down until a refactoring descriptor is found.

Overrides:
getDescriptor in class Change
Returns:
a descriptor of this change, or null if this change does not provide a change descriptor.
Since:
3.2

toString

public 
String toString()
Overrides:
toString in class Object

Eclipse Platform
Release 3.5

Guidelines for using Eclipse APIs.

Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.


 
 
  Published under the terms of the Eclipse Public License Version 1.0 ("EPL") Design by Interspire