Eclipse JDT
Release 3.0

org.eclipse.ltk.core.refactoring
Class TextChange

java.lang.Object
  extended byorg.eclipse.ltk.core.refactoring.Change
      extended byorg.eclipse.ltk.core.refactoring.TextChange
All Implemented Interfaces:
IAdaptable
Direct Known Subclasses:
DocumentChange, TextFileChange

public abstract class TextChange
extends Change

A text change is a special change object that applies a text edit tree to a document. The text change manages the text edit tree. Access to the document must be provided by concrete subclasses via the method aquireDocument, commitDocument, and releaseDocument.

A text change offers the ability to access the original content of the document as well as creating a preview of the change. The edit tree gets copied when creating any king of preview. Therefore no region updating on the original edit tree takes place when requesting a preview (for more information on region updating see class TextEdit. If region tracking is required for a preview it can be enabled via a call to the method setKeepPreviewEdits. If enabled the text change keeps the copied edit tree executed for the preview allowing clients to map an original edit to an executed edit. The executed edit can then be used to determine its position in the preview.

Note: this class is not intended to be subclassed outside the refactoring framework.

Since:
3.0

Constructor Summary
protected TextChange(String name)
          Creates a new text change with the specified name.
 
Method Summary
protected abstract  IDocument acquireDocument(IProgressMonitor pm)
          Acquires a reference to the document to be changed by this text change.
 void addTextEditChangeGroup(TextEditChangeGroup group)
          Adds a text edit change group.
 void addTextEditGroup(TextEditGroup group)
          Adds a text edit group.
protected abstract  void commit(IDocument document, IProgressMonitor pm)
          Commits the document acquired via a call to aquireDocument.
protected abstract  Change createUndoChange(UndoEdit edit)
          Hook to create an undo change for the given undo edit.
 String getCurrentContent(IProgressMonitor pm)
          Returns the current content of the document this text change is associated with.
 String getCurrentContent(IRegion region, boolean expandRegionToFullLine, int surroundingLines, IProgressMonitor pm)
          Returns the current content of the text change clipped to a specific region.
 IDocument getCurrentDocument(IProgressMonitor pm)
          Returns the document this text change is associated to.
 TextEdit getEdit()
          Returns the root text edit.
 boolean getKeepPreviewEdits()
          Returns whether preview edits are remembered for further region tracking or not.
 String getName()
          Returns the human readable name of this change. The name MUST not be null.
 String getPreviewContent(IProgressMonitor pm)
          Returns the preview content as a string.
 String getPreviewContent(TextEditChangeGroup[] changeGroups, IRegion region, boolean expandRegionToFullLine, int surroundingLines, IProgressMonitor pm)
          Returns a preview of the text change clipped to a specific region.
 IDocument getPreviewDocument(IProgressMonitor pm)
          Returns a document containing a preview of the text change.
 TextEdit getPreviewEdit(TextEdit original)
          Returns the edit that got executed during preview generation instead of the given original.
 TextEdit[] getPreviewEdits(TextEdit[] originals)
          Returns the edits that were executed during preview generation instead of the given array of original edits.
 TextEditChangeGroup[] getTextEditChangeGroups()
          Returns the text edit change groups managed by this text change.
 String getTextType()
          Returns the text change's text type.
 Change perform(IProgressMonitor pm)
          Performs this change. If this method is call 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.
protected abstract  void releaseDocument(IDocument document, IProgressMonitor pm)
          Releases the document acquired via a call to aquireDocument.
 void setEdit(TextEdit edit)
          Sets the root text edit that should be applied to the document represented by this text change.
 void setEnabled(boolean enabled)
          Sets whether this change is enabled or not.
 void setKeepPreviewEdits(boolean keep)
          Controls whether the text change should keep executed edits during preview generation.
 void setTextType(String type)
          Sets the text type.
 
Methods inherited from class org.eclipse.ltk.core.refactoring.Change
dispose, getAdapter, getModifiedElement, getParent, initializeValidationData, isEnabled, isValid
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

TextChange

protected TextChange(String name)
Creates a new text change with the specified name. The name is a human-readable value that is displayed to users. The name does not need to be unique, but it must not be null.

The text type of this text change is set to txt.

Parameters:
name - the name of the text change
See Also:
setTextType(String)
Method Detail

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

setEnabled

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

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

setTextType

public void setTextType(String type)
Sets the text type. The text type is used to determine the content merge viewer used to present the difference between the original and the preview content in the user interface. Content merge viewers are defined via the extension point org.eclipse.compare.contentMergeViewers.

The default text type is txt.

Parameters:
type - the text type. If null is passed the text type is reseted to the default text type txt.

getTextType

public String getTextType()
Returns the text change's text type.

Returns:
the text change's text type

setEdit

public void setEdit(TextEdit edit)
Sets the root text edit that should be applied to the document represented by this text change.

Parameters:
edit - the root text edit. The root text edit can only be set once.

getEdit

public TextEdit getEdit()
Returns the root text edit.

Returns:
the root text edit or null if no root edit has been set

addTextEditGroup

public void addTextEditGroup(TextEditGroup group)
Adds a text edit group. This method is a convenient method for calling change.addTextEditChangeGroup(new TextEditChangeGroup(change, group));.

Parameters:
group - the text edit group to add

addTextEditChangeGroup

public void addTextEditChangeGroup(TextEditChangeGroup group)
Adds a text edit change group. Calling the methods requires that a root edit has been set via the method setEdit. The edits managed by the given text edit change group must be part of the change's root edit.

Parameters:
group - the text edit change group to add

getTextEditChangeGroups

public TextEditChangeGroup[] getTextEditChangeGroups()
Returns the text edit change groups managed by this text change.

Returns:
the text edit change groups

acquireDocument

protected abstract 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 releaseDocument(IDocument, IProgressMonitor).

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

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 abstract 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.

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

releaseDocument

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

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

createUndoChange

protected abstract 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.

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 creating the undo change.

perform

public Change perform(IProgressMonitor pm)
               throws CoreException
Performs this change. If this method is call 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.

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

getCurrentDocument

public IDocument getCurrentDocument(IProgressMonitor pm)
                             throws CoreException
Returns the document this text change is associated to. The document returned is computed at the point in time when this method is called. So calling this method multiple times may return different document instances.

The returned document must not be modified by the client. Doing so will result in an unexpected behaviour when the change is performed.

Parameters:
pm - a progress monitor to report progress or null if no progress reporting is desired
Returns:
the document this change is working on
Throws:
CoreException - if the document can't be acquired

getCurrentContent

public String getCurrentContent(IProgressMonitor pm)
                         throws CoreException
Returns the current content of the document this text change is associated with.

Parameters:
pm - a progress monitor to report progress or null if no progress reporting is desired
Returns:
the current content of the text change
Throws:
CoreException - if the content can't be accessed

getCurrentContent

public String getCurrentContent(IRegion region,
                                boolean expandRegionToFullLine,
                                int surroundingLines,
                                IProgressMonitor pm)
                         throws CoreException
Returns the current content of the text change clipped to a specific region. The region is determined as follows:

Parameters:
region - the starting region for the text to be returned
expandRegionToFullLine - if true is passed the region is extended to cover full lines
surroundingLines - the number of surrounding lines to be added to the clipping region. Is only considered if expandRegionToFullLine is true
pm - a progress monitor to report progress or null if no progress reporting is desired
Returns:
the current content of the text change clipped to a region determined by the given parameters.
Throws:
CoreException - if an exception occurs while accessing the current content

setKeepPreviewEdits

public void setKeepPreviewEdits(boolean keep)
Controls whether the text change should keep executed edits during preview generation.

Parameters:
keep - if true executed preview edits are kept

getKeepPreviewEdits

public boolean getKeepPreviewEdits()
Returns whether preview edits are remembered for further region tracking or not.

Returns:
true if executed text edits are remembered during preview generation; otherwise false

getPreviewEdit

public TextEdit getPreviewEdit(TextEdit original)
Returns the edit that got executed during preview generation instead of the given original. The method requires that setKeepPreviewEdits is set to true and that a preview has been requested via one of the getPreview* methods.

The method returns null if the original isn't managed by this text change.

Parameters:
original - the original edit managed by this text change
Returns:
the edit executed during preview generation

getPreviewEdits

public TextEdit[] getPreviewEdits(TextEdit[] originals)
Returns the edits that were executed during preview generation instead of the given array of original edits. The method requires that setKeepPreviewEdits is set to true and that a preview has been requested via one of the getPreview* methods.

The method returns an empty array if none of the original edits is managed by this text change.

Parameters:
originals - an array of original edits managed by this text change
Returns:
an array of edits containing the corresponding edits executed during preview generation

getPreviewDocument

public IDocument getPreviewDocument(IProgressMonitor pm)
                             throws CoreException
Returns a document containing a preview of the text change. The preview is computed by executing the all managed text edits. The method considers the active state of the added text edit change groups.

Parameters:
pm - a progress monitor to report progress or null if no progress reporting is desired
Returns:
a document containing the preview of the text change
Throws:
CoreException - if the preview can't be created

getPreviewContent

public String getPreviewContent(IProgressMonitor pm)
                         throws CoreException
Returns the preview content as a string. This is a convenient method for calling getPreviewDocument(IProgressMonitor).get().

Parameters:
pm - a progress monitor to report progress or null if no progress reporting is desired
Returns:
the preview
Throws:
CoreException - if the preview can't be created

getPreviewContent

public String getPreviewContent(TextEditChangeGroup[] changeGroups,
                                IRegion region,
                                boolean expandRegionToFullLine,
                                int surroundingLines,
                                IProgressMonitor pm)
                         throws CoreException
Returns a preview of the text change clipped to a specific region. The preview is created by applying the text edits managed by the given array of text edit change groups. The region is determined as follows:

Parameters:
changeGroups - a set of change groups for which a preview is to be generated
region - the starting region for the clipping
expandRegionToFullLine - if true is passed the region is extended to cover full lines
surroundingLines - the number of surrounding lines to be added to the clipping region. Is only considered if expandRegionToFullLine is true
pm - a progress monitor to report progress or null if no progress reporting is desired
Returns:
the current content of the text change clipped to a region determined by the given parameters.
Throws:
CoreException - if an exception occurs while generating the preview
See Also:
getCurrentContent(IRegion, boolean, int, IProgressMonitor)

Eclipse JDT
Release 3.0

Copyright (c) IBM Corp. and others 2000, 2004. All Rights Reserved.