public interface PositionRepresents a location within a document. It is intended to abstract away implementation details of the document and enable specification of positions within the document that are capable of tracking of change as the document is edited.
Positionobject points at a location between two characters. As the surrounding content is altered, the
Positionobject adjusts its offset automatically to reflect the changes. If content is inserted or removed before the
Positionobject's location, then the
Positionincrements or decrements its offset, respectively, so as to point to the same location. If a portion of the document is removed that contains a
Position's offset, then the
Position's offset becomes that of the beginning of the removed region. For example, if a
Positionhas an offset of 5 and the region 2-10 is removed, then the
Position's offset becomes 2.
Positionwith an offset of 0 is a special case. It never changes its offset while document content is altered.