| Represents 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.
A
Position object points at a location between two characters.
As the surrounding content is altered, the
Position object
adjusts its offset automatically to reflect the changes. If content is
inserted or removed before the
Position object's location, then the
Position increments 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
Position has an offset of 5 and the region 2-10 is removed, then
the
Position 's offset becomes 2.
Position with an offset of 0 is a special case. It never changes its
offset while document content is altered.
author:
Timothy Prinzing
version:
1.26 05/05/07 |