Violet and VPL Database Manual

Don Batory
Department of Computer Science
The University of Texas at Austin
Austin, TX, USA

Violet is a free Java tool for drawing UML class diagrams. Familiarize yourself with Violet by installing MDELite and invoking it:

> java MDELite.Violet

and drawing the diagram below:

Draw your own diagrams. When you feel comfortable, proceed to the next section.

Violet Database Schema

Violet encodes a class diagram as an ugly XML file. The MDELite.ClassVioletParser tool translates Violet-XML documents into a database that conforms to the following schema:

% Violet (vpl) class database

dbase(vpl,[vBox,vAssociation]).

% type = c(class),i(nterface),n(ote).  packages are skipped
% abst : if type==c, is class abstract?
% abstract class names are prefaced by "Abs_"

table(vBox,[id,type,"name","fields","methods",abst:bool,x,y]).

% type* = c(lass) or i(nterface)
% lineStyle = ""(solid) or "DOTTED"
% arrow1,2 = V, TRIANGLE, DIAMOND, BLACK_DIAMOND
% bentStyle = "", HV, VH, HVH, VHV
% abst -- if type==c, is class abstract?

table(vAssociation,[id,cid1:vBox,type1,"role1","arrow1",cid2:vBox,type2,"role2","arrow2","bentStyle","lineStyle","middleLabel"]).

Some notes:

vBox is the name of a table with 6 columns.

id is the internal identifier of a vBox tuple (class, interface, or note)
type is "c" class or "i" interface or "n" for note
name, fields, methods are single-quoted strings which contain the name of the class, the string of fields and methods for that class.
x,y are coordinate positions at which this class is displayed.
abst : if type==c, is the class abstract? (Abstract class names are prefaced by "Abs_")

vAssociation is a table with 11 columns.

id is the internal identifier of an association.
cid1,cid2 are identifiers of classes or interfaces to be connected.
type1,type2 are enums with values "c" for class or "i" for interface to type cid1 and cid2.
role1,role2 -- is any text eg name and/or cardinality to be displayed.
arrow1,arrow2 -- only values {V, NONE, TRIANGLE, DIAMOND, BLACK_DIAMOND}, where NONE is ''.
linestyle -- only values {SOLID, DOTTED}.
bentStyle -- only values {STRAIGHT (or blank),HV,VH,HVH,VHV}.
middleLabel -- should be blank, but this is the middle label on a Violet association

Let SC.class.violet be the Violet-produced XML file for StudentCourse. The following MDELite command translates this file into a VPL database SC.vpl.pl:

> java MDELite.VioletClassParser SC.class.violet SC.vpl.pl

The database that is produced is:

dbase(vpl,[vBox,vAssociation]).

table(vBox,[id,type,"name","fields","methods",abst:bool,x,y]).
vBox(ClassNode0,c,'Student','name','',false,160.0,180.0).
vBox(ClassNode1,c,'Course','name','',false,411.0,177.0).
vBox(ClassNode2,c,'Student','name','',false,619.0,181.0).
vBox(ClassNode3,c,'Course','name','',false,870.0,178.0).
vBox(ClassNode4,c,'Student','name','',false,159.0,300.0).
vBox(ClassNode5,c,'Course','name','',false,410.0,297.0).
vBox(ClassNode6,c,'Course','name','',false,870.0,296.0).
vBox(ClassNode7,c,'Student','name','',false,619.0,299.0).
vBox(ClassNode8,c,'Course','name','',false,410.0,421.0).
vBox(ClassNode9,c,'Student','name','',false,162.0,424.0).
vBox(ClassNode10,c,'Course','name','',false,870.0,416.0).
vBox(ClassNode11,c,'Student','name','',false,614.0,419.0).
vBox(ClassNode12,c,'Course','name','',false,409.0,529.0).
vBox(ClassNode13,c,'Student','name','',false,153.0,531.0).
vBox(ClassNode14,c,'Course','name','',false,1275.0,184.0).
vBox(ClassNode15,c,'Student','name','',false,1035.0,179.0).
vBox(ClassNode16,c,'Student','name','',false,1038.0,290.0).
vBox(ClassNode17,c,'Course','name','',false,1289.0,287.0).
vBox(ClassNode18,c,'Course','name','',false,1291.0,406.0).
vBox(ClassNode19,c,'Student','name','',false,1040.0,409.0).
vBox(ClassNode20,c,'Person','name','',false,848.0,580.0).
vBox(ClassNode21,c,'Person','name','',false,646.0,567.0).
vBox(ClassNode22,c,'x','','',false,1139.0,566.0).
vBox(ClassNode23,c,'y','','',false,1339.0,575.0).

table(vAssociation,[id,cid1:vBox,type1,"role1","arrow1",cid2:vBox,type2,"role2","arrow2","bentStyle","lineStyle","middleLabel"]).
vAssociation(A0,ClassNode0,c,'has','',ClassNode1,c,'loves','','','','').
vAssociation(A1,ClassNode2,c,'','',ClassNode3,c,'','','','','enroll').
vAssociation(A2,ClassNode4,c,'','',ClassNode5,c,'takes','','','','').
vAssociation(A3,ClassNode7,c,'','',ClassNode6,c,'','BLACK_DIAMOND','','','takes').
vAssociation(A4,ClassNode9,c,'','',ClassNode8,c,'takes','','','','').
vAssociation(A5,ClassNode11,c,'','',ClassNode10,c,'','DIAMOND','','','takes').
vAssociation(A6,ClassNode13,c,'*','',ClassNode12,c,'*','','','','takes').
vAssociation(A7,ClassNode15,c,'5','',ClassNode14,c,'2','','','','enroll').
vAssociation(A8,ClassNode16,c,'4','',ClassNode17,c,'','BLACK_DIAMOND','','','takes').
vAssociation(A9,ClassNode19,c,'4','',ClassNode18,c,'','DIAMOND','','','takes').
vAssociation(A10,ClassNode20,c,'','',ClassNode20,c,'','','VHV','','parents,children').
vAssociation(A11,ClassNode21,c,'parents','',ClassNode21,c,'chlidren','','HVH','','').
vAssociation(A12,ClassNode22,c,'','',ClassNode22,c,'','V','HVH','','boo').
vAssociation(A13,ClassNode23,c,'','',ClassNode23,c,'','V','HVH','','foo').

VPL Constraints

There indeed are VPL constraints. I have not posted them, as they are good examples for homework assignments. They are similar to those for YPL (VPL's Yuml counterpart).