USOO6212672B1 (12) United States Patent (10) Patent No.: US 6,212,672 B1 Keller et al. (45) Date of Patent: *Apr. 3, 2001

(54) SOFTWARE DEVELOPMENT SYSTEM OTHER PUBLICATIONS WITH AN EXECUTABLE WORKING MODEL IN AN INTERPRETABLE INTERMEDIATE Compilers Principles, Techniques and Tools Aho et al. MODELING LANGUAGE Chapter 8 Intermediate Code Generation, pp. 463-465, Sep. 1985.* (75) Inventors: Steven Keller, Hampstead, NH (US); Teach Yourself Visual Basic for Applications in 21 Days, pp. Richard Gorzela, Lawrence, MA (US); 28-36, Dec. 1994.* Daniel Strom, North Andover, MA Object-Oriented Modeling and Design, James Rumbaugh et (US); David Hughes, Arlington, MA al. pp. 57-62, Nov. 14, 1990.* (US); James Holt, Needham, MA (US) Template Software Inc. “User's Guide to the SNAP Devel opment Environment” version 7.0, 1995.* (73) Assignee: Dynamics Research Corporation, Template Softweare Inc. “User’s Guide to the Development Wilmington, MA (US) Process' version 7.0, 1995.* Template Software, “Using the SNAP Development Envi (*) Notice: This patent issued on a continued pros- ronment SNAP Foundation Environment Chpts 1-3, ecution application filed under 37 CFR 1998.* 1.53(d), and is subject to the twenty year patent term provisions of 35 U.S.C. “Template Software Strenthens . . . ”, Newswire, Product 154(a)(2). release information for version 8.0, 1998.* - 0 (List continued on next page.) Subject to any disclaimer, the term of this patent is extended or adjusted under 35 Primary Examiner Mark R. Powell U.S.C. 154(b) by 0 days. Assistant Examiner Todd Ingberg (74) Attorney, Agent, or Firm Weingarten, Schurgin, (21) Appl. No.: 08/813,487 Gagnebin & Hayes LLP (57) ABSTRACT (22)22) FileFilled: Mar.ar, 7,f, 1997 A Software development tool utilizes an intermediate object 7 modeling language. The Structure of the desired program is (51) Int. Cl.? .… G06F 9/44 first described graphically by generating rule diagrams, State diagrams, and object diagrams Such as user interface (52) U.S. C. SL LSSLLSSLLSL LSSLLSSLLSSLLSSL LSLLSLLSL LSSLLSSLLSSL LSLLSLLSL LSSLLSSLLSSL LSLLSLLSL LSSLLSSLLSSLLSSL LSLLSLLSL LSSLLSSLLSSL LSLLSLLSL LSSLLSSLLSL LSSLLSSLLSSLLSSL LSLLSLLSL LSSLLSSLLSSL LSLLSLLSL LSSLLSSLLSSL LSLLSLLSL LSSLLSSLLSSLLSSL LSLLSLLSL LSSLLS 717/1 diagrams, eVent diagrams and other object diagrams. The development tool employs the diagrams to generate a work (58) Field of Sea???/703,704,705,706, }A. : ing model of the program expressed in the object modeling 717/1, 2 language. The working model of the program can be executed without lengthy compiling, and hence program (56) References Cited behavior can be quickly observed and tested. Further, the behavior of the working model can be quickly and easily U.S. PATENT DOCUMENTS changed by modifying the diagrams until the desired result

5,487,141 1/1996 Cain et al...... 395/135 is achieved. Source code is then generated from the object 5.537,630 7/1996 Berry et al...... 395/155 modeling language and compiled to create the final program. 5,720,018 * 2/1998 Muller et al. . ... 395/702 5,742,828 * 4/1998 Canady et al. ... 395/702 5,764,241 6/1998 Elliot et al...... 395/702 92 Claims, 36 Drawing Sheets

12 OBJECTDAGRAMS 16 14 18 UEDAGRAMS ? RULE STATE DIAGRAMS) 20-EVENTDAGRAMS--THEREENS DIAGRAMS

OMML -wa

31> | GENERATOR

SOURCE - DISPLAY? DAABASE 26 CODE 28 TERMINAL

FINAL PROGRAM N-10 US 6,212,672 B1 Page 2

OTHER PUBLICATIONS Computer Language "Smelling Like a Rose’ Tom Bragg, Mar. 1993. Template Software Product release version 6.0, Sep. 1994. * “Principles of Object-Oriented Analysis and Design” James Data Based Advisor “A Rose is a Rose’ D. Goddard, Mar. Martin Text Book, Oct. 1992.* 1995.* Visual Object Oriented Programming Concepts and Envi Rational Software Corporation-Using Rational Rose C++ roments: M. Burnett et al Text Book, Dec. 1994.* version 4.0, 1996. * Windows Tech Journal “The Seet Smell of C++” KWeeks, Sep.1994.* * cited by examiner U.S. Patent Apr. 3, 2001 Sheet 1 of 36 US 6,212,672 B1

OBJECT DIAGRAMS 16 12 14 UDAGRAMS RULE STATE EVENT DIAGRAMS DAGRAMS DIAGRAMS OTHERDAGRAMS

OML INTERPRETER

G

/ ENERATOR SOURCE DISPLAYI DATABASE CODE TERMINAL

FINAL PROGRAM

FIG. I. U.S. Patent Apr. 3, 2001 Sheet 2 of 36 US 6,212,672 B1

Z'OIH U.S. Patent Apr. 3, 2001 Sheet 3 of 36 US 6,212,672 B1

dA/pJBMJO

?IEMIOJ 08 9(9.I.H.

#"SOIAI U.S. Patent Apr. 3, 2001 Sheet 4 of 36 US 6,212,672 B1

EXIT 94 ??tr? 88 State A time-Out State B entrylcallhome do: time-out(2000) e?callhome 90 92 FIG. 6

90 An Event Diagram 90 FIG. 7

Purchase Requisitio SourceEntity ...Total/Cost Vice President largeCOst - aDDrOVal/ largeCostPrologue f . . . . " : large0COst ?TotalCOst

ARULE DAGRAM ENIG 8 U.S. Patent Apr. 3, 2001 Sheet 5 of 36 US 6,212,672 B1

?98 o TurnKey(Clutchy on FIG 9

NewCausePrologue NeWCause NewCause NewCauseEpilogue ASSOciation Arity ArgNo Satisfied AddtoMenu

----- 100 - 102 - 104 FIG 10A Object 440

Causename(object effect) Causename(object effect) Effectname{Object Rule Action,…) : 446 s 448 FIG. I (OB U.S. Patent Apr. 3, 2001 Sheet 6 of 36 US 6,212,672 B1

SomeCause ThirdEffect FOurthEffect ThirdEffect RuleAction? RuleACtion8 FourthEffect RuleAction.9 RuleAction 10

SeCOndEffect ThirdEffect FirstEffect RuleAction1 RuleAction3 RuleACtion5 SeCOndEffect RuleACtion2 RuleAction4 RuleAction6

SomeCauSe en ." >138 ArgNo y ?~134 Satisfied a. AdiroMenu (c.138 136 FIG. I2 FIG. 13 U.S. Patent Apr. 3, 2001 Sheet 7 of 36 US 6,212,672 B1

backackgroung d green A Planned ASSOCiation FIG. I.5

DoSomething - employs

Define ... I DefineFrOmReS DefineWithinh . Compare . Call o?somevariable Unit FIG. 20 U.S. Patent Apr. 3, 2001 Sheet 8 of 36 US 6,212,672 B1

178 182 180 Arguments (SomeUni184 I. 186 Load DeleteUnit . 188

. SomeUnit -N175 FIG 21

DoSomething Pop Push Push

FIG. 22

204

200 Somethi DoSomething 206 Rename H. <> ???" AnotherUnit ... I <> "" 08

. 210 202 `???mess??? FIG. 23 U.S. Patent Apr. 3, 2001 Sheet 9 of 36 US 6,212,672 B1

218 DoSomething " 1?? | | <><> * a 220

216 FIG. 24 * FIG. 25

230 234 228 || DoSomething -- SomeUnit SetLocation || C> ". ?csomepathunitfilefil236

240

"SomeUnit DoSomething [TRUE] SetOrdered || ...“ ASSert ... owns 258 ASSert "...... ASSert ?? "...... ASSert

. employs 246 244 FIG. 27 U.S. Patent Apr. 3, 2001 Sheet 10 Of 36 US 6,212,672 B1

DoSomething 268 DoSomething Unload || "Someunit - 270

266 FIG. 28 FIG. 29

DOSomething TimedCalCause - 4000 SideEffect || ". PayEmployee . 276

272 FIG. 30

280 282 . Color(Carred) 284 doit = (- Define . 286

FIG. 31 U.S. Patent Apr. 3, 2001 Sheet 11 of 36 US 6,212,672 B1

300

FIG. 32 . doit Define

302 "Color(Carred) 304 Term 306 TermArgNo

FIG. 33 Define '. 308

doit Arguments "| drives ASSert H.

Car FIG. 34 U.S. Patent Apr. 3, 2001 Sheet 12 of 36 US 6,212,672 B1

314 doit " PayEmployee Call 320 . 322

FIG. 35

314 312 320 doit - PayEmployee Cal|| || . || ||Cause ||||||| ". 322

316 324 FIG. 36

326 Cat (Via <> 328 KI> “. 330 FIG, 37 doit a ????? Define . U.S. Patent Apr. 3, 2001 Sheet 13 of 36 US 6,212,672 B1

XmPUShButton

338 - labelString 336

PlabelValue

Define FrOm ReSOUrce i. 340 Define 334 renas. FIG 38

348 ??emp]~36

FIG. 39

354 doit Function p??

SideEffect. ... Name<> - “... VisualMagic

FIG. 40 U.S. Patent Apr. 3, 2001 Sheet 14 Of 36 US 6,212,672 B1

358

360 362 "Button 364 IsSubclaSS Subclass … Coit |Superclass || -....XmPushButton Define *

FIG. 42

Color(car, red) 37

368

FIG. 43

U.S. Patent Apr. 3, 2001 Sheet 16 of 36 US 6,212,672 B1

390

doit

(Ptemp)- Y392 ... Bob FIG. 48

398 400

r4000 COit ?? PayEmployee Side Effect Interval . . . 402 ... Cause Object . 404 . 2temp FIG. 49

406

UnitLOCation

408? Unit ...... ??? 412 doit . . . Define .

LSL itemp}\to FIG. 504 U.S. Patent Apr. 3, 2001 Sheet 17 of 36 US 6,212,672 B1

414

416 <>

|5| FIG. 50B

702

704 706 FIG. 5IB

FIG 51A U.S. Patent Apr. 3, 2001 Sheet 18 of 36 US 6,212,672 B1

Translating Diagrams To OML Models 426?? 424 OWns Building Cashier Station Owns (Bank,CashierStation) Owns (Bank, Building) FIG. 52

isA (Station1,CashierStation) 430 isA (Station2,CashierStation)

428 FIG. 53

432 434 Supervises Employee

Supervises (Supervisor,Employee) Supervises (Fido,Buttons) isA (Fido,Dog) isA (Buttons,Cat) FIG. 54 U.S. Patent Apr. 3, 2001 Sheet 19 Of 36 US 6,212,672 B1

MAP Display 29 Disk Storage Event -drawing Map.dat rdb, dat 454?? 45 6 User Interface

Initial Incremental Loading Load/UnloadUnits sssr callback

0>DB 450 Or terms ?????????? Rule Action

OML Interpreter

Call Relational C++ Function Database 470 468

U.S. Patent Apr. 3, 2001 Sheet 21 of 36 US 6,212,672 B1

Active entrylightOn1 530 ????exitfightOff 532 change

entrylchange(3000)

SourceEntity 500 Object s 506 lightOnPrologue

504

lightOfPrologue

Define Define

Define Put

FIG. 62 U.S. Patent Apr. 3, 2001 Sheet 22 of 36 US 6,212,672 B1 U.S. Patent Apr. 3, 2001 Sheet 23 of 36 US 6,212,672 B1

909 U.S. Patent US 6,212,672 B1 U.S. Patent Apr. 3, 2001 Sheet 25 of 36 US 6,212,672 B1 U.S. Patent Apr. 3, 2001 Sheet 26 of 36 US 6,212,672 B1

|799(5)IAI U.S. Patent

189 U.S. Patent Apr. 3, 2001 Sheet 28 of 36 US 6,212,672 B1

999

799999

019 Z/9

)

789 U.S. Patent Apr. 3, 2001 Sheet 29 Of 36 US 6,212,672 B1

Z9%)IH

U.S. Patent Apr. 3, 2001 Sheet 31 of 36 US 6,212,672 B1

09/

$799(9IAI

89/99/

U.S. Patent Apr. 3, 2001 Sheet 32 of 36 US 6,212,672 B1

Generate

748 Generate Causes for each wiMHaS CauSe 750 756 752 G t 754 Generate GS8G CauSe Function Cause Prologue Generate CauSeS Epilogue -Call to Prologue -Call to iterator for(same prologue) as -Call to Epilogue

762 758 Generate Cause ??????????????????" Effects Alternatives Calls 9 764 for each Handles Calls to Alternative superclass functions 76C if this function fails Generate Cause Alternative Call

FIG. 68C U.S. Patent Apr. 3, 2001 Sheet 33 of 36 US 6,212,672 B1

758 Generate Effects

766 770 Generate 768 si Effect Prototype Generate Effect alternetS Definition 772 Generate For each Rule Action Rule Action generateAttributedefine Define generateSimpleDefine generateDefineFrmResource TranslateTermorruleACtion Put generatecodeForput Defi genCodeForAssertlsln eThe genCodeForAssertlsA genCodeForAssert

SetValue genCodeForSet

Retract translateCodeForSimpleRetract

PODUD generateCodeForpopup

POOdoWn generatecodeForpopdown

Call generateCodeForCall • o (other) FIG. 68D U.S. Patent Apr. 3, 2001 Sheet 34 of 36 US 6,212,672 B1

DetermineAttributeType: Determines type of Destination president TypesMatch: Destination See if AttributeType is compatible with the Destination Type FIG. 69

616 fourthColumn

622 WarChar(40 third Column 624 This diagram will generate the following SQL statements: CREATE TABLE"firstTable"("firstColumn"WarChar(40), 626 "secondColumn"WarChar(40),"thirdColumn"WarChar(40) and CREATE TABLE"secondTable"("fourthColumn"WarChar(40) FIG. 70 U.S. Patent Apr. 3, 2001 Sheet 35 0f 36 US 6,212,672 B1

OZ9

799

?? (~~~~~)GNW IZ(OICH U.S. Patent Apr. 3, 2001 Sheet 36 of 36 US 6,212,672 B1

firStColumn *SelectExample . -666 '•r . . . 2OperationResult theoDatabaseThings Store 3. statementreturn Select ..- ?668

Fetch " * - ... fetchreturn Retrieve Insert Update Delete Close CurSOr

ReSultTable . SQLInSert -"insertObject Object - ReSult ...... insertResult SQUpdate "*| DeleteObject i?cursorToClose . HSTMT ...... ?????? 2CUrSOrStatement s Result ...... ??? ?updateResult i SQLDeletel i . Object ? ... ."'" Update0bject HSTMT|.. Result ...... deleteResult

FIG. 72 US 6,212,672 B1 1 2 SOFTWARE DEVELOPMENT SYSTEM changes in the diagrams and can be directly executed WITH AN EXECUTABLE WORKING MODEL without lengthy compilation. As a result, program changes IN AN INTERPRETABLE INTERMEDIATE can be implemented and observed in a shorter amount of MODELING LANGUAGE time. BACKGROUND OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWING A recognized problem in the field of Software develop The invention will be more fully understood in view of the ment is error in translation from Specified requirements to a following Detailed Description of the Invention and working program. According to one Software development Drawing, of which: model, a written Specification which describes planned FIG. 1 is a block diagram illustrating operation of the behavior for the program is created prior to beginning Software development tool; development of any Software code. The Specification is FIG. 2 is an object diagram; meant to be used by Software engineers as a guide when FIG. 3 is a user interface diagram; Writing the code So that the program functions as planned. FIG. 4 is a palette of predefined objects; However, because the Specification may be inaccurate, 15 incomplete and describe a poor design, and because the FIG. 5 is a state diagram; Software engineers may fail to precisely follow the Specifi FIG. 6 is a state diagram which further illustrates actions; cation during development, the resulting program may differ FIG. 7 is an event diagram; from the planned program. If the differences are significant FIG. 8 is a rule diagram; enough, the program may have to be rewritten or otherwise FIG. 9 is a state diagram which illustrates interaction altered. As a result, development time and development between States and rules, costs are increased. FIG. 10A illustrates cause segments; BRIEF SUMMARY OF THE INVENTION FIG. 10B illustrates a rule; 25 FIG. 11 illustrates use and interaction of cause Segments, A Software development tool which utilizes an interme diate object modeling language is disclosed. The Structure of FIG. 12 further illustrates a cause Segment; the desired program is first described graphically by gener FIG. 13 illustrates an iterator; ating rule diagrams, State diagrams, and object diagrams FIG. 14 is an object diagram; Such as user interface diagrams, event diagrams and other FIG. 15 is a planned association; object diagrams. The development tool employs the dia FIGS. 16-30 illustrate rule actions; grams to generate a working model of the program FIGS. 31-51 illustrate expressions; expressed in the object modeling language. The working FIGS. 52-54 illustrate object diagrams and corresponding model of the program can be executed without lengthy modeling language code, compiling, and hence program behavior can be quickly 35 FIG. 55 illustrates operation of the interpreter and map; observed and tested. Further, the behavior of the working model can be quickly and easily changed by modifying the FIG. 56 illustrates operation of the assertion interpreter; diagrams until the desired result is achieved. Source code is FIG. 57 is an object diagram associated with a traffic light then generated from the object modeling language and example program; compiled to create the final program. FIG. 58 is an event diagram associated with the example 40 program, Classes and associations which inter-relate classes are employed as fundamental constructs in the diagrams and FIG. 59 is an object diagram associated with the example object modeling language. No distinction is drawn between program, classes and instances. This trait is desirable, for example, FIG. 60 is a state diagram associated with the example program, when an analyst discovers that an object classified as an 45 instance actually has Several occurrences, each possibly with FIGS. 61 and 62 are rule diagrams associated with the different characteristics. It is desirable in Such an event to example program; directly Subclass that object rather than create a new class FIGS. 63-65 illustrate object modeling language code that captures the characteristics of the object in general and asSociated with the example program; reclassify the object as an instance of that new class. 50 FIG. 66 is a flow diagram which illustrates processing of One advantage provided by the development tool is direct State diagrams; development and implementation of program Specifications. FIG. 67 illustrates special predicates which are employed The diagrams facilitate development of a program Specifi to accommodate typing requirements for Source code gen cation or “business model” for the program by visually eration; organizing and representing real world Systems in an intui 55 FIGS. 68A-68D illustrate source code generation; tive manner. Hence, the program Specification may be FIG. 69 illustrates type matching; directly developed diagrammatically. Further, Since the tool FIG.70 illustrates generation of a relational database table employs the diagrams to create Source code, human errors in using SQL Statements created from an object diagram; translating the Specification to code are eliminated. FIG. 71 illustrates generation of an SQL query from an Another advantage provided by the development tool is 60 object diagram; and Speedy implementation of modifications during develop FIG.72 illustrates database related rules for integration of ment. Known development environments typically require database functions with the program. implementing changes in Source code and then compiling the Source code to create a working program that can be DETAILED DESCRIPTION OF THE tested to determine whether the changes produce the desired 65 INVENTION result. By contrast, the modeling language of the present An operational Overview of the Software development development tool is automatically modified to reflect tool is illustrated in FIG. 1. The development tool provides US 6,212,672 B1 3 4 the user with a graphic environment for development of a tate creation of commonly used interface features Such as Software program 10. More particularly, the desired opera windows, buttons and fields, e.g., XmTextField 66. Further, tion of the program 10 is first represented diagrammatically user developed objects and Structures may be added to the using rule diagrams 12, State diagrams 14, and object palette. diagrams 16 including user interface diagrams 18, event diagrams 20 and other object diagrams 22. While such FIG. 5 illustrates a state diagram 14 (FIG. 1). The state diagrams are being formed, a representation 24 of the diagram includes labeled States which are interconnected by program is contemporaneously and automatically made in transitions. The illustrated States include an Active state 68, an object modeling language by employing an interpreter 25 a Requisitioning State 70, a Creating Requisition State 72, a and user interface 27 to determine meaning from the dia Manager reviewing state 74 and other states. The illustrated grams. The representation of the program in the modeling transitions include a Forward transition 76, a Forward/ language is operational and can utilize both a database 26 for Manager Approved transition 78, a Forward transition 80, a retrieval and Storage of information and a display/terminal Forward/VP Approved transition 82 and a Forward/ 29 for I/O functions. Because the modeling language rep Contracts Manager Approved transition 84. resentation of the program is operational, it may be The State diagram is associated with at least one object, employed to determine whether the final program 10, which 15 and defines different states of objects modeled in the state is expressed in another language, will function as planned. diagram and State Sequences caused by inputted events. If program changes are necessary, the diagrams are modified Transitions are labeled with the event which causes the by the user and the modeling language representation 24 is transition to occur. For example, the forward event 76 is automatically modified by the development tool to reflect required before transitioning from the Creating Requisition the diagram changes. Source code 28 in a Selected object state 72 to the Manager Reviewing state 74. States may be oriented language Such as C++ is created from the modeling nested within Superstates referred to as “contours.” For language representation 24 by a generator 31 when all example, Requisitioning 70 is a contour containing the desired changes have been made. The Source code 28 is then Substrates Creating Requisition 72 and Manager Reviewing compiled to generate the final program 10. 74. Entry points into contours and states are defined by solid FIG. 2 illustrates an object diagram. The object diagram 25 circles 86. includes a plurality of objects represented by rectangular Referring to FIG. 6 in which a portion of a state diagram blockS. Objects may be linked together by associations is illustrated, actions may be set to occur when an object which are represented by lines between objects. ASSocia reaches a chosen State. PoSSible types of actions include: an tions represent relationships between classes, and are gen entry action 88, a do action 90, an event action 92, and an erally described with text Strings. For example, a Manager exit action 94. Entry actions 88 are triggered immediately object 30 is connected to a Department object 32 by a upon entry of the associated State. Do actions 90 trigger after “manages' association 34. Hence, the manager manages a entry actions 88 complete and continue until completed or department. the occurrence of an event that causes a transition out of the ASSociations which represent many-to-one, one-to-many asSociated State. Event actions 92 are triggered when a and many-to-many relationships are indicated by multiplic 35 predetermined event occurs. However, Such an event does ity dots 36. In particular, a multiplicity dot is associated with not cause a transition to another State. Exit actions 94 trigger an object to indicate that the object can be “many” in the immediately before leaving the associated State. relationship defined by the association. For example, a The actions may be defined in various different ways. For requisitioner 38 may create 40 many purchase requisitions 40 example, if an action is defined as a “cause, the develop 42, and the purchase requisition 42 may list 44 many items ment tool will execute any rule cause having the same name 46. as the action. If the action is defined as an “event,” the Object inheritance may be established by connecting development tool causes that event to occur. The occurrence objects with an inheritance association 48 which is repre of Such an event may lead to the firing of a transition or the Sented by a line and triangle and indicates an “is a type 45 occurrence of an event action. If the action is defined as a relationship, Sometimes referred to using the terms “class, “timer,” a timer function is executed. The timer function has subclass and superclass.” For example, Manager 30 “is an” an integer argument. The timer generates the event after the Employee 49, and hence Manager is a subclass of the number of time units (milliseconds) indicated by the argu Superclass Employee. Further, a plurality of Subclasses may ment has elapsed. Actions may also take place on transitions. be connected with an inheritance association and collec 50 When the transition fires, the action is executed before tively connected to a Superclass. For example, Manager 30 entering the new State. is a Superclass of Comptroller 50, Chief Executive Officer FIG. 7 illustrates an event diagram 20 (FIG. 1). All events 52, Department Manager 54, Chief Financial Officer 56 and that affect transitions in the State diagram are defined in an Vice President 58. event diagram, which is a type of object diagram. In FIG.3 illustrates a user interface diagram 18 (FIG. 1) The 55 particular, the event diagram is an object diagram in which user interface diagram is a form of object diagram which is events 90 are defined as objects. For clarity, each of the employed to create a user interface for the program. Aggre event objectS is made a Subclass of a predefined Event object gation associations 60 which indicate that an object 62 is an 92. element of another object 64 are represented with a line and FIG. 8 illustrates a rule diagram 12 (FIG. 1). Rule a diamond. In particular, a line is drawn between the two 60 diagrams define activity in the program, and are employed objects with the diamond pointing towards the aggregate. If to extend object diagrams and State diagrams Such that the multiple objects share a Single aggregate, lines from all the program operates in the desired manner. The rules defined objects converge into a single line which is connected to the by the diagram includes causes 94 and effects 96, and may aggregate by another line. Aggregation associations 60 may be executed from other rules or a State diagram. When a rule be employed with any object diagram. 65 is executed, the development tool Searches for a cause Referring to FIG. 4, a palette of predefined objects and having a name matching the name of the rule and attempts Structures containing multiple objects are provided to facili to execute that cause. In particular, when the object associ US 6,212,672 B1 S 6 ated with the State diagram reaches the Specified State, the Cause alternatives 446 are executed in the order that they entry action is executed, and hence the cause is executed. occur, Stopping on the first alternative that Succeeds. A cause When the tool eXecutes a rule, it Searches for a cause that is alternative Succeeds when the corresponding effect Suc bound to a particular specified object 42. If Such a cause does ceeds. AS Stated above, effects are executed in order of not exist, then a cause that is bound to the immediate occurrence, until a conditional action fails or the last effect Superclass of that particular object is Sought. If Such a cause is completed. When the last effect is completed, the effect does not exist at the immediate Superclass, the tool continues Succeeds. If none of the cause alternatives Succeeds, then the Searching upwards in the inheritance hierarchy until a cause fails. matching cause is located. The rule applicable to a given object is bound at run-time, Referring to FIG. 9, a transition 98 may be conditionally 1O the applicable rule being the innermost rule in the generali fired based on a rule. In particular, the transition may be zation hierarchy. If that cause fails, a more general cause (the asSociated with a rule, and if a specified event, e.g., Clutch, innermost more general cause) is invoked and So on until a occurs then the rule is executed. If the rule completes then cause Succeeds or no more causes are found. the transition is fired. If the rule does not complete then the Referring to FIG. 11, each alternative 108 in a cause is transition is not fired. 15 asSociated with a corresponding effect, and each effect is Referring to FIG. 10A, there are four types of cause bound to one object. Each effect contains a list of rule segments 94 (FIG. 8): prologue 100, iterator 102, middle actions 110 which are predefined routines. When an alter 104 and epilogue 106. The causes are arranged in a hierarchy native 108 is executed, the tool searches for and attempts to that defines order of execution. In particular, prologues 100 execute an effect 96 of the same name that is bound to the occur first, followed respectively by iterators 102, middles same object as the cause. When an effect 96 is executed, 104 and epilogues 106. Each cause is bound to an object in execution of each associated rule action 110 is Sequentially a one-to-one relationship, and may contain a list of param attempted. If all of the rule actions 110 are successfully eters and alternatives. completed, the cause 116 that called the effect is also Referring to FIG. 10B, rules are employed to implement completed. If a rule action is not Successful, execution of methods in the object modeling language. Rules are com 25 that effect terminates and the next alternative 108 is prised of an object 440, a cause 442 and an effect 444. The attempted. Similarly, if an alternative Specifies execution of cause 442 and effect 444 are modeled as associations with a an effect that is not bound to the desired object, the tool Specific form. Searches upwards in the inheritance hierarchy until the The cause 442 is comprised of a set of cause alternatives appropriate effect is located. 446, each of which is an association. For example, a cause It should be noted that a cause and effect need not be PayS on object Company could take the form: Company bound to the same object. For example, given a State Pays (with alternative) PaysExempt and parameters (P1, P2 diagram attached to an object Maple 112 which is a Subclass through Pn), and Company Pays (with alternative) Pays of Tree 114, where Maple calls a rule named SomeCause Nonexempt and parameters (P1, P2 through Pn). The alter (not illustrated), the cause SomeCause 116 is executed. natives are related rules that can be invoked by a single 35 Since there is no effect which is named "SomeEffect” and name. First level rules take the form: bound to Maple, the effect bound to the superclass of Maple (