org.eclipse.ltk.core.refactoring
Class NullChange
java.lang.Object
org.eclipse.ltk.core.refactoring.Change
org.eclipse.ltk.core.refactoring.NullChange
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All Implemented Interfaces:
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IAdaptable
-
public class NullChange
- extends
Change
A refactoring change that does nothing. The reverse change of a
NullChange is a NullChange.
Note: this class is not intended to be extended by clients.
-
Since:
- 3.0
-
Restriction:
- This class is not intended to be subclassed by clients.
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Constructor Summary
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NullChange
()
Creates a new NullChange with a default name. |
NullChange
(
String name)
Creates a new NullChange with the given name. |
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Methods inherited from class java.lang.
Object
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clone,
equals,
finalize,
getClass,
hashCode,
notify,
notifyAll,
toString,
wait,
wait,
wait
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NullChange
public NullChange()
- Creates a new
NullChange with a default name.
NullChange
public NullChange(
String name)
- Creates a new
NullChange with the given name.
-
Parameters:
-
name - the human readable name of this change
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
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.
-
-
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.
-
-
Specified by:
-
isValid
in class
Change
-
-
Parameters:
-
pm - a progress monitor.
-
Returns:
- a refactoring status describing the outcome of the validation check
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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.
-
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Specified by:
-
perform
in class
Change
-
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Parameters:
-
pm - a progress monitor
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Returns:
- the undo change for this change object or
null if no
undo is provided
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Throws:
-
CoreException
- if an error occurred during change execution
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
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Returns:
- the element modified by this change
Guidelines for using Eclipse APIs.
Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.
