Class DefaultPositionUpdater

  • All Implemented Interfaces:
    IPositionUpdater
    Direct Known Subclasses:
    MultiPassContentFormatter.NonDeletingPositionUpdater

    public class DefaultPositionUpdater
    extends Object
    implements IPositionUpdater
    Default implementation of IPositionUpdater.

    A default position updater must be configured with the position category whose positions it will update. Other position categories are not affected by this updater.

    This implementation follows the specification below:

    • Inserting or deleting text before the position shifts the position accordingly.
    • Inserting text at the position offset shifts the position accordingly.
    • Inserting or deleting text strictly contained by the position shrinks or stretches the position.
    • Inserting or deleting text after a position does not affect the position.
    • Deleting text which strictly contains the position deletes the position. Note that the position is not deleted if its only shrunken to length zero. To delete a position, the modification must delete from strictly before to strictly after the position.
    • Replacing text contained by the position shrinks or expands the position (but does not shift it), such that the final position contains the original position and the replacing text.
    • Replacing text overlapping the position in other ways is considered as a sequence of first deleting the replaced text and afterwards inserting the new text. Thus, a position is shrunken and can then be shifted (if the replaced text overlaps the offset of the position).
    This class can be used as is or be adapted by subclasses. Fields are protected to allow subclasses direct access. Because of the frequency with which position updaters are used this is a performance decision.
    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected IDocument fDocument
      Caches the document
      protected int fLength
      Caches the length of the replaced text
      protected int fOffset
      Caches the offset of the replaced text
      protected Position fOriginalPosition
      Caches the original state of the investigated position
      protected Position fPosition
      Caches the currently investigated position
      protected int fReplaceLength
      Caches the length of the newly inserted text
    • Constructor Summary

      Constructors 
      Constructor Description
      DefaultPositionUpdater​(String category)
      Creates a new default position updater for the given category.
    • Field Detail

      • fPosition

        protected Position fPosition
        Caches the currently investigated position
      • fOriginalPosition

        protected Position fOriginalPosition
        Caches the original state of the investigated position
      • fOffset

        protected int fOffset
        Caches the offset of the replaced text
      • fLength

        protected int fLength
        Caches the length of the replaced text
      • fReplaceLength

        protected int fReplaceLength
        Caches the length of the newly inserted text
      • fDocument

        protected IDocument fDocument
        Caches the document
    • Constructor Detail

      • DefaultPositionUpdater

        public DefaultPositionUpdater​(String category)
        Creates a new default position updater for the given category.
        Parameters:
        category - the category the updater is responsible for
    • Method Detail

      • getCategory

        protected String getCategory()
        Returns the category this updater is responsible for.
        Returns:
        the category this updater is responsible for
      • isAffectingReplace

        protected boolean isAffectingReplace()
        Returns whether the current event describes a well formed replace by which the current position is directly affected.
        Returns:
        true the current position is directly affected
        Since:
        3.0
      • adaptToInsert

        protected void adaptToInsert()
        Adapts the currently investigated position to an insertion.
      • adaptToRemove

        protected void adaptToRemove()
        Adapts the currently investigated position to a deletion.
      • adaptToReplace

        protected void adaptToReplace()
        Adapts the currently investigated position to the replace operation. First it checks whether the change replaces only a non-zero range inside the range of the position (including the borders). If not, it performs first the deletion of the previous text and afterwards the insertion of the new text.
      • notDeleted

        protected boolean notDeleted()
        Determines whether the currently investigated position has been deleted by the replace operation specified in the current event. If so, it deletes the position and removes it from the document's position category.
        Returns:
        true if position has not been deleted
      • update

        public void update​(DocumentEvent event)
        Description copied from interface: IPositionUpdater
        Adapts positions to the change specified by the document event. It is ensured that the document's partitioning has been adapted to this document change and that all the position updaters which have a smaller index in the document's position updater list have been called.
        Specified by:
        update in interface IPositionUpdater
        Parameters:
        event - the document event describing the document change