Package org.eclipse.ltk.core.refactoring

Class TextChange

  • All Implemented Interfaces:
    IAdaptable
    Direct Known Subclasses:
    DocumentChange, TextFileChange
    public abstract class TextChange
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 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

      • 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

      • 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
        Description copied from class: Change
        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​(IRegion region,
                                boolean expandRegionToFullLine,
                                int surroundingLines,
                                IProgressMonitor pm)
                         throws CoreException
        Description copied from class: TextEditBasedChange
        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​(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
        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
        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)
        Description copied from class: TextEditBasedChange
        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