Eclipse Plug-in Developer Guide (Galileo) - TextFileChange (Eclipse Platform API Specification)

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Eclipse Platform
Release 3.5

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org.eclipse.ltk.core.refactoring
Class TextFileChange


java.lang.Object
  

org.eclipse.ltk.core.refactoring.Change
      

org.eclipse.ltk.core.refactoring.TextEditBasedChange
          

org.eclipse.ltk.core.refactoring.TextChange
              
org.eclipse.ltk.core.refactoring.TextFileChange

All Implemented Interfaces:: IAdaptable

public class TextFileChange
extends TextChange
extends TextChange

A special TextChange that operates on a IFile.

As of 3.1 the content stamp managed by a text file change maps to the modification stamp of its underlying IFile. Undoing a text file change will roll back the modification stamp of a resource to its original value using the new API IResource.revertModificationStamp(long)

The class should be subclassed by clients which need to perform special operation when acquiring or releasing a document.

Since:: 3.0

Field Summary

static int FORCE_SAVE
          Flag (value 2) indicating that the file is to be saved after the change has been applied.

static int KEEP_SAVE_STATE
          Flag (value 1) indicating that the file's save state has to be kept.

static int LEAVE_DIRTY
          Flag (value 4) indicating that the file will not be saved after the change has been applied.

Constructor Summary

TextFileChange ( String name, IFile file)
          Creates a new TextFileChange for the given file.

Method Summary

protected IDocument acquireDocument ( IProgressMonitor pm)
          Acquires a reference to the document to be changed by this text change.

protected void commit ( IDocument document, IProgressMonitor pm)
          Commits the document acquired via a call to aquireDocument.

protected Change createUndoChange ( UndoEdit edit)
          Hook to create an undo change for the given undo edit.

protected Change createUndoChange ( UndoEdit edit, ContentStamp stampToRestore)
          Hook to create an undo change for the given undo edit and content stamp.

void dispose ()
          Disposes this change.

Object[] getAffectedObjects ()
          Returns the elements affected by this change or null if the affected elements cannot be determined.

IFile getFile ()
          Returns the IFile this change is working on.

Object getModifiedElement ()
          Returns the element modified by this Change.

int getSaveMode ()
          Returns the save state set via setSaveMode(int).

void initializeValidationData ( IProgressMonitor monitor)
          Hook method to initialize some internal state to provide an adequate answer for the isValid method.

protected boolean isDocumentAcquired ()
          Is the document currently acquired?

protected boolean isDocumentModified ()
          Has the document been modified since it has been first acquired by the change?

RefactoringStatus isValid ( IProgressMonitor monitor)
          Verifies that this change object is still valid and can be executed by calling perform.

protected boolean needsSaving ()
          Does the text file change need saving?

protected UndoEdit performEdits ( IDocument document)
          Executes the text edits on the given document.

protected void releaseDocument ( IDocument document, IProgressMonitor pm)
          Releases the document acquired via a call to aquireDocument.

void setSaveMode (int saveMode)
          Sets the save state.

Methods inherited from class org.eclipse.ltk.core.refactoring. TextChange

addEdit, addTextEditChangeGroup, addTextEditGroup, getCurrentContent, getCurrentContent, getCurrentDocument, getEdit, getPreviewContent, getPreviewContent, getPreviewContent, getPreviewDocument, getPreviewEdit, getPreviewEdits, getTextEditChangeGroups, perform, setEdit, setKeepPreviewEdits

Methods inherited from class org.eclipse.ltk.core.refactoring. TextEditBasedChange

addChangeGroup, getChangeGroups, getKeepPreviewEdits, getName, getTextType, hasOneGroupCategory, setEnabled, setTextType

Methods inherited from class org.eclipse.ltk.core.refactoring. Change

getAdapter, getDescriptor, getParent, isEnabled, setEnabledShallow

Methods inherited from class java.lang. Object

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

Field Detail

KEEP_SAVE_STATE

public static final int KEEP_SAVE_STATE

Flag (value 1) indicating that the file's save state has to be kept. This means an unsaved file is still unsaved after performing the change and a saved one will be saved.

See Also:: Constant Field Values

FORCE_SAVE

public static final int FORCE_SAVE

Flag (value 2) indicating that the file is to be saved after the change has been applied.

See Also:: Constant Field Values

LEAVE_DIRTY

public static final int LEAVE_DIRTY

Flag (value 4) indicating that the file will not be saved after the change has been applied.

See Also:: Constant Field Values

Constructor Detail

TextFileChange

public TextFileChange(
String name,
                      
IFile file)

Creates a new TextFileChange for the given file.

Parameters:: name - the change's name mainly used to render the change in the UI; file - the file this text change operates on

Method Detail

setSaveMode

public void setSaveMode(int saveMode)

Sets the save state. Must be one of KEEP_SAVE_STATE, FORCE_SAVE or LEAVE_DIRTY.

Parameters:: saveMode - indicating how save is handled when the document gets committed

getSaveMode

public int getSaveMode()

Returns the save state set via setSaveMode(int).

Returns:: the save state

getFile

public 
IFile getFile()

Returns the IFile this change is working on.

Returns:: the file this change is working on

createUndoChange

protected 
Change createUndoChange(
UndoEdit edit,
                                  
ContentStamp stampToRestore)

Hook to create an undo change for the given undo edit and content stamp. This hook gets called while performing the change to construct the corresponding undo change object.

Parameters:: edit - the UndoEdit to create an undo change for; stampToRestore - the content stamp to restore when the undo edit is executed.
Returns:: the undo change or null if no undo change can be created. Returning null results in the fact that the whole change tree can't be undone. So returning null is only recommended if an exception occurred during creating the undo change.

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

getAffectedObjects

public 
Object[] getAffectedObjects()

Description copied from class: Change

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

initializeValidationData

public void initializeValidationData(
IProgressMonitor monitor)

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:: monitor - a progress monitor

isValid

public 
RefactoringStatus isValid(
IProgressMonitor monitor)
                          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:: monitor - 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

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.

Overrides:: dispose in class Change

acquireDocument

protected 
IDocument acquireDocument(
IProgressMonitor pm)
                             throws 
CoreException

Acquires a reference to the document to be changed by this text change. A document acquired by this call MUST be released via a call to TextChange.releaseDocument(IDocument, IProgressMonitor).

The method releaseDocument must be called as many times as aquireDocument has been called.

Specified by:: acquireDocument in class TextChange

Parameters:: pm - a progress monitor
Returns:: a reference to the document to be changed
Throws:: CoreException - if the document can't be acquired

commit

protected void commit(
IDocument document,
                      
IProgressMonitor pm)
               throws 
CoreException

Commits the document acquired via a call to aquireDocument. It is up to the implementors of this method to decide what committing a document means. Typically, the content of the document is written back to the file system.

The implementation of this method only commits the underlying buffer if needsSaving() and isDocumentModified() returns true.

Specified by:: commit in class TextChange

Parameters:: document - the document to commit; pm - a progress monitor
Throws:: CoreException - if the document can't be committed

releaseDocument

protected void releaseDocument(
IDocument document,
                               
IProgressMonitor pm)
                        throws 
CoreException

Releases the document acquired via a call to aquireDocument.

Specified by:: releaseDocument in class TextChange

Parameters:: document - the document to release; pm - a progress monitor
Throws:: CoreException - if the document can't be released

createUndoChange

protected final 
Change createUndoChange(
UndoEdit edit)

Hook to create an undo change for the given undo edit. This hook gets called while performing the change to construct the corresponding undo change object.

Specified by:: createUndoChange in class TextChange

Parameters:: edit - the UndoEdit to create an undo change for
Returns:: the undo change or null if no undo change can be created. Returning null results in the fact that the whole change tree can't be undone. So returning null is only recommended if an exception occurred during the creation of the undo change.

performEdits

protected 
UndoEdit performEdits(
IDocument document)
                         throws 
BadLocationException,
                                
MalformedTreeException

Description copied from class: TextChange

Executes the text edits on the given document. Subclasses that override this method should call super.performEdits(document).

Overrides:: performEdits in class TextChange

Parameters:: document - the document
Returns:: an object representing the undo of the executed edits
Throws:: BadLocationException - is thrown if one of the edits in the tree can't be executed. The state of the document is undefined if this exception is thrown.; MalformedTreeException - is thrown if the edit tree isn't in a valid state. This exception is thrown before any edit is executed. So the document is still in its original state.

isDocumentAcquired

protected boolean isDocumentAcquired()

Is the document currently acquired?

Returns:: true if the document is currently acquired, false otherwise
Since:: 3.2

isDocumentModified

protected boolean isDocumentModified()

Has the document been modified since it has been first acquired by the change?

Returns:: Returns true if the document has been modified since it got acquired by the change. false is returned if the document has not been acquired yet, or has been released already.
Since:: 3.3

needsSaving

protected boolean needsSaving()

Does the text file change need saving?

The implementation of this method returns true if the FORCE_SAVE flag is enabled, or the underlying file is not dirty and KEEP_SAVE_STATE is enabled.

Returns:: true if it needs saving according to its dirty state and the save mode flags, false otherwise
Since:: 3.3

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Guidelines for using Eclipse APIs.

org.eclipse.ltk.core.refactoring Class TextFileChange

KEEP_SAVE_STATE

FORCE_SAVE

LEAVE_DIRTY

TextFileChange

setSaveMode

getSaveMode

getFile

createUndoChange

getModifiedElement

getAffectedObjects

initializeValidationData

isValid

dispose

acquireDocument

commit

releaseDocument

createUndoChange

performEdits

isDocumentAcquired

isDocumentModified

needsSaving

org.eclipse.ltk.core.refactoring
Class TextFileChange