javax.swing.text.GapContent — clojure-interop/javax.swing 1.0.5

An implementation of the AbstractDocument.Content interface implemented using a gapped buffer similar to that used by emacs. The underlying storage is a array of unicode characters with a gap somewhere. The gap is moved to the location of changes to take advantage of common behavior where most changes are in the same location. Changes that occur at a gap boundary are generally cheap and moving the gap is generally cheaper than moving the array contents directly to accommodate the change.

The positions tracking change are also generally cheap to maintain. The Position implementations (marks) store the array index and can easily calculate the sequential position from the current gap location. Changes only require update to the the marks between the old and new gap boundaries when the gap is moved, so generally updating the marks is pretty cheap. The marks are stored sorted so they can be located quickly with a binary search. This increases the cost of adding a mark, and decreases the cost of keeping the mark updated.

->gap-content clj

(->gap-content)

(->gap-content initial-length)

Constructor.

Creates a new GapContent object, with the initial size specified. The initial size will not be allowed to go below 2, to give room for the implied break and the gap.

initial-length - the initial size - int

create-position clj

(create-position this offset)

Creates a position within the content that will track change as the content is mutated.

offset - the offset to track >= 0 - int

returns: the position - javax.swing.text.Position

throws: javax.swing.text.BadLocationException - if the specified position is invalid

get-chars clj

(get-chars this where len chars)

Retrieves a portion of the content. If the desired content spans the gap, we copy the content. If the desired content does not span the gap, the actual store is returned to avoid the copy since it is contiguous.

where - the starting position >= 0, where len <= length() - int len - the number of characters to retrieve >= 0 - int chars - the Segment object to return the characters in - javax.swing.text.Segment

throws: javax.swing.text.BadLocationException - if the specified position is invalid

get-string clj

(get-string this where len)

Retrieves a portion of the content.

where - the starting position >= 0 - int len - the length to retrieve >= 0 - int

returns: a string representing the content - java.lang.String

throws: javax.swing.text.BadLocationException - if the specified position is invalid

insert-string clj

(insert-string this where str)

Inserts a string into the content.

where - the starting position >= 0, < length() - int str - the non-null string to insert - java.lang.String

returns: an UndoableEdit object for undoing - javax.swing.undo.UndoableEdit

throws: javax.swing.text.BadLocationException - if the specified position is invalid

length clj

(length this)

Returns the length of the content.

returns: the length >= 1 - int

remove clj

(remove this where nitems)

Removes part of the content.

where - the starting position >= 0, where nitems < length() - int nitems - the number of characters to remove >= 0 - int

returns: an UndoableEdit object for undoing - javax.swing.undo.UndoableEdit

throws: javax.swing.text.BadLocationException - if the specified position is invalid