PEG creation_history--tjl: Object creation order RDF schema

Author: Tuomas Lukka
Date-Created:2003-07-28
Last-Modified:2003-08-04
Revision: 1.6
Status: Accepted
Stakeholders:benja, mudyc, humppake
Scope:Minor
Type:Architecture

Time isn't always linear. It can branch. Maybe we should keep track of the creation of objects as a tree based on versions.

Issues

System Message: ERROR/3 (../ffdoc/fenfire/pegboard/creation_history--tjl/peg.rst, line 20)

Section empty; must have contents.

Changes

Create a new namespace, http://fenfire.org/rdf-v/2003/07/treetime.

This namespace shall contain:

/** An time-like ordering between creation of objects.
 */
public class TREETIME {
    /** A type that declares a relation to be 
     * a time-like relation.
     * This namespace defines one time-like relation,
     * "follows" for common use, more may be defined
     * to avoid conflicts, using the TimeRelation class.
     */
    static public final Object TimeRelation;

    /** (A, follows, B) means that A was created after B.
     */
    static public final Object follows;

    /** (X, currentOf, follows) means that X is the latest
     * entity in a "follows" chain. This applies to other
     * relations, too.
     */
    static public final Object currentOf;

    /** (X, firstOf, follows) means that X is the root
     * of a "follows" chain. This applies to other relations,
     * too.
     */
    static public final Object firstOf;
}

These would be used to keep track of in what order canvases were created and PDF files imported in FenPDF.

When merging, all but one currentOf relations would be deleted.

The treeness arises from merging: merge does not have to artificially pack the sequences into one sequence but can just take all "follows" triples from all versions, hence the name.