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

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Eclipse Platform
Release 3.5

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org.eclipse.ltk.core.refactoring
Class TextChange


java.lang.Object
  

org.eclipse.ltk.core.refactoring.Change
      

org.eclipse.ltk.core.refactoring.TextEditBasedChange
          
org.eclipse.ltk.core.refactoring.TextChange

All Implemented Interfaces:: IAdaptable

Direct Known Subclasses:: DocumentChange, TextFileChange

public abstract class TextChange
extends TextEditBasedChange
extends TextEditBasedChange

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 kind 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
Restriction:: This class is not intended to be subclassed by clients.

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 addEdit ( TextEdit edit)
          Adds the given edit to the edit tree.

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 edit 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.

String getPreviewContent ( IProgressMonitor pm)
          Returns the preview content as a string.

String getPreviewContent ( TextEditBasedChangeGroup[] changeGroups, IRegion region, boolean expandRegionToFullLine, int surroundingLines, IProgressMonitor pm)
          Returns a preview of the text change clipped to a specific region.

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.

Change perform ( IProgressMonitor pm)
          Performs this change.

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

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

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

dispose, getAdapter, getAffectedObjects, getDescriptor, getModifiedElement, getParent, initializeValidationData, isEnabled, isValid, setEnabledShallow

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:: TextEditBasedChange.setTextType(String)

Method Detail

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 convenience method for calling

change.addTextEditChangeGroup(new
TextEditChangeGroup(change, group));

Overrides:: addTextEditGroup in class TextEditBasedChange

Parameters:: group - the text edit group to add

addTextEditChangeGroup

public void addTextEditChangeGroup(
TextEditChangeGroup group)

Adds a text edit change group. Calling this method 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

addEdit

public void addEdit(
TextEdit edit)
             throws 
MalformedTreeException

Adds the given edit to the edit tree. The edit is added as a top level edit.

Parameters:: edit - the text edit to add
Throws:: MalformedTreeException - if the edit can't be added. Reason is that is overlaps with an already existing edit
Since:: 3.1

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 called 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 the creation of the undo change.

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.

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

performEdits

protected 
UndoEdit performEdits(
IDocument document)
                         throws 
BadLocationException,
                                
MalformedTreeException

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

Parameters:: document - the document
Returns:: an object representing the undo of the executed edits
Throws:: 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.; 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.
Since:: 3.5

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 behavior 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.

Specified by:: getCurrentContent in class TextEditBasedChange

Parameters:: pm - a progress monitor to report progress or null if no progress reporting is desired
Returns:: the current content of the text edit 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 edit change clipped to a specific region. The region is determined as follows:

if expandRegionToFullLine is false then the parameter region determines the clipping.
if expandRegionToFullLine is true then the region determined by the parameter region is extended to cover full lines.
if surroundingLines > 0 then the given number of surrounding lines is added. The value of surroundingLines is only considered if expandRegionToFullLine is true

Specified by:: getCurrentContent in class TextEditBasedChange

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 edit change clipped to a region determined by the given parameters.
Throws:: CoreException - if an exception occurs while accessing the current content

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.

Specified by:: getPreviewContent in class TextEditBasedChange

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:

if expandRegionToFullLine is false then the parameter region determines the clipping.
if expandRegionToFullLine is true then the region determined by the parameter region is extended to cover full lines.
if surroundingLines > 0 then the given number of surrounding lines is added. The value of surroundingLines is only considered if expandRegionToFullLine is true

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)

getPreviewContent

public 
String getPreviewContent(
TextEditBasedChangeGroup[] changeGroups,
                                
IRegion region,
                                boolean expandRegionToFullLine,
                                int surroundingLines,
                                
IProgressMonitor pm)
                         throws 
CoreException

if expandRegionToFullLine is false then the parameter region determines the clipping.
if expandRegionToFullLine is true then the region determined by the parameter region is extended to cover full lines.
if surroundingLines > 0 then the given number of surrounding lines is added. The value of surroundingLines is only considered if expandRegionToFullLine is true

Specified by:: getPreviewContent in class TextEditBasedChange

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
Since:: 3.2
See Also:: getCurrentContent(IRegion, boolean, int, IProgressMonitor)

setKeepPreviewEdits

public void setKeepPreviewEdits(boolean keep)

Controls whether the text edit change should keep executed edits during preview generation.

Overrides:: setKeepPreviewEdits in class TextEditBasedChange

Parameters:: keep - if true executed preview edits are kept

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Eclipse Platform
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Guidelines for using Eclipse APIs.

org.eclipse.ltk.core.refactoring Class TextChange

TextChange

setEdit

getEdit

addTextEditGroup

addTextEditChangeGroup

getTextEditChangeGroups

addEdit

acquireDocument

commit

releaseDocument

createUndoChange

perform

performEdits

getCurrentDocument

getCurrentContent

getCurrentContent

getPreviewEdit

getPreviewEdits

getPreviewDocument

getPreviewContent

getPreviewContent

getPreviewContent

setKeepPreviewEdits

org.eclipse.ltk.core.refactoring
Class TextChange