Package org.eclipse.ltk.core.refactoring

Class DocumentChange

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.DocumentChange
All Implemented Interfaces:
IAdaptable
public class DocumentChange extends TextChange
A text change that operates directly on instances of IDocument. The document change uses a simple length compare to check if it is still valid. So as long as its length hasn't changed the text edits managed have a valid range and can be applied to the document. The same applies to the undo change returned from the perform method.

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.

  • Constructor Details

    • DocumentChange

      public DocumentChange(String name, IDocument document)
      Creates a new DocumentChange for the given IDocument.
      Parameters:
      name - the change's name. Has to be a human readable name.
      document - the document this change is working on

  • Method Details

    • getModifiedElement

      public Object getModifiedElement()
      Description copied from class: Change
      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

    • initializeValidationData

      public void initializeValidationData(IProgressMonitor pm)
      Description copied from class: Change
      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
      Description copied from class: Change
      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
      Throws:
      CoreException - if an error occurred during validation check. The change is to be treated as invalid if an exception occurs

    • acquireDocument

      protected IDocument acquireDocument(IProgressMonitor pm) throws CoreException
      Description copied from class: TextChange
      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
      Description copied from class: TextChange
      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.
      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
      Description copied from class: TextChange
      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

    • 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.

    • createUndoChange

      protected Change createUndoChange(UndoEdit edit)
      Description copied from class: TextChange
      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.