SLIDE 1 Asp ects
Building W eb Application Systems Using the MBASE Approac h Anca-Juliana Stoica 15th In t F
SCM/F
W
USC-CSE, Oct.2000
SLIDE 2 Con ten ts 1. In tro duction 2. W eb Application Systems 3. Arc hitecture 4. W eb T ec hnologies 5. Asp ects
Building W AS (a) The Pro cess (b) Requiremen ts and Use Cases 6. Additional Mo deling Issues Connected to W AS (a) W eb Application Extension
UML 7. Applying the MBASE Approac h to W AS Dev elopmen t 8. Cost Mo deling and Estimation (a) Mo deling and Estimation (b) An Algorithm for Estimation based
Use Cases 9. Conclusion
SLIDE 3 I. In tro duction W eb Application Systems W AS is a W eb System (WS) that allo ws its users to execute business logic with a bro wser. A W AS:
dynamic
collab
e con ten ts, and distributed comm unities
the w eb
with man y dieren t stak eholders
to b e arc hitected for con tin uous c hange
to cop e with p erio ds
p eak in teraction
sp ecic W eb tec hnologies suc h as: HTML, XML, EJB, SSL, CGI, TCIP/IP , ASP , JSP , ...
SLIDE 4 Mo del Based (System) Arc hitecting and Soft w are Engineering The MBASE approac h:
the most complete system
in terconnected mo dels for soft w are dev elopmen t to date
a sound theoretical foundation
supp
for analysing mo del clashes
exibilit y , adaptabilit y , ease
extension.
SLIDE 5 W e found that the MBASE approac h is v ery useful for represen tation
the success, pro duct, pro cess, and prop ert y asp ects
a W AS and that there is a synergy b et w een dev eloping W AS and dev eloping MBASE, in the sense that:
the framew
for analysing and mo delling W AS to meet the critical success factors for soft w are pro jects
AS
the information to enhance MBASE mo dels (or create new
for this sp ecic soft w are systems.
SLIDE 6 I I. W eb Application Systems W eb Application Systems are built b y w ebifying clien t/serv er systems and in tegrating legacy . T ypically these systems are asso ciated with:
infrastructure
W eb system
business logic
W eb application
arc hitecture for the W eb application
tec hnologies, dynamic clien ts, and distributed
jects. The most adv anced suc h systems reengineer and automate complete businesses pro viding highly p ersonalized, adaptiv e solutions. Some c haracteristics asso ciated with dev eloping W AS are:
imp
and complex rules and regulations
fo cus
terface with legacy data structures
concern for p erformance and reliabilit y .
SLIDE 7 I I I. Arc hitecture The most basic arc hitectural comp
ts are:
t bro wser
w
connection
eb serv er
serv er, whic h enables the system to manage business logic and state.
SLIDE 8
SLIDE 9 Figure 1: Generalized W AS arc hitecture.
SLIDE 10 The basic arc hitectural comp
ts are used in 3 arc hitectural patterns,
fundamen tal structural
sc hemas:
W eb Clien t
k W eb Clien t
eb Deliv ery System The dierence from traditional clien t/serv er systems is that W AS construct W eb-sp ecic comp
ts, namely W eb pages. These are arc hitecturally signican t comp
ts b ecause they exist b
in the mo del and in the executable system.
SLIDE 11 IV. W eb T ec hnologies Enabling T ec hnologies Pro vide the infrastructure for building W eb applications, in particular the mec hanism b y whic h W eb pages b ecome dynamic and resp
to user input. Examples include: CGI (Common Gatew a y In terface), Activ e Serv er P ages (ASP), Ja v a Serv er P ages (JSP), servlets, and W eb serv er APIs suc h as ISAPI (In ternet Serv er API), NSAPI (Netscap e Serv er API) Enabling tec hnologies are used as dev elopmen t en vironmen ts that lead to new business
New business
in turn, lead to c hanged business practices (see Fig.2).
SLIDE 12 Enabling Technologies. New Business Opportunities. Changed Business Practices.
Figure 2: The role
enabling tec hnologies.
SLIDE 13 Other W eb tec hnologies are used for:
co de from UML mo dels: ASP , VBScript
t-side scripting: HTML, XML, Ja v aScript, VBScript, Applets, Activ e X con trols, DOM
t-serv er proto cols: HTTP , DCOM, CORBA/I IOP , Ja v a RMI
the W AS: sc hemes to protect conden tial information
er the net suc h as SET (Secure Electronic T ransaction), SSL(Secure So c k et La y er)
SLIDE 14 V. Asp ects
Building W AS A. The Pro cess
customer
tation (\customer" here is dened as a user
a compan y)
role
use cases that: i) driv e the pro cess, ii) are a resource for nearly ev ery activit y in the pro cess, iii) help manage and attac k risks, and iv) ev ery w
er t ypically reviews the use cases to v alidate decisions made during w
activities
relationships with the business pro cess
stak eholders to consider for the Win-Win nego ciations
inuence
enabling tec hnologies, sp ecic arc hitectures, and new comp
ts (suc h as the W eb pages)
\dev eloping W eb-time" approac h
new approac h to W eb UI protot yping
artifacts
SLIDE 15 B. Requiremen ts and Use Cases
do cumen ts and mo dels to unam bigously describ e the soft w are to b e built
cases capture and express the system b eha vior
mo dels giv e input to the use case view and help to iden tify actors and use cases
eloping W eb-time solutions imply to unify creativ e design and soft w are engineering pro cesses.
SLIDE 16 VI. Additional Mo deling Issues Connected to W AS A. W eb Application Extension
UML
SLIDE 17
Icon Server Page Client Page Form Frameset Target
SLIDE 18 Examples
using the W eb Application Extension
UML
SLIDE 19
SLIDE 20 VI I. Applying the MBASE Approac h to W AS Dev elopmen t A.Mo del Systems
requirements Delivered software system Users MODEL SYSTEM
Figure 3: Mo del system.
SLIDE 21 B.The MBASE approac h applied to W AS.
SLIDE 22
Process Models * Major Milestones * LCO * LCA * IOC * Architectural * WAS artifacts. (web pages, forms, framesets, targets..) Product Models Property Models. * Robustness, Scalability, * Progress and Quality Entry / Exit V & V Evaluation and * Win−Win Spiral * RUP 2000e Success Models Patterns for WAs * UML and WAE * Enabling Technologies Analysis * Cost and Schedule * Use Case Metrics Feature Richness, Response Time, Usability * Sizing Metrics Metrics * Decision Framework * Business Model * Mission−Critical * Creative Design * User−Centered * Win−Win Criteria Criteria Product Development & Evolution Process * COTS and RAD
SLIDE 23 VI I I. Cost Mo deling and Estimation A. Mo deling and Estimation
Goal Definition. Choose a Model. (Data Dependence) Choose Model Structure. Parameter Estimation Validation. Collected Data. New Data. Use The Model. Yes. No.
SLIDE 24 An Algorithm for Estimating W
With Use Cases 1. T
actors T a = 3 P i=1 (na i )
a i ) i = S = A =C : Complexit y: Simple/Av erage/Complex : na =n um b er
a v erage actors; W a =W eigh t
an actor. Actors complexit y in terms
actor in teraction mec hanisms: API / Comm unication Proto cols / GUI. 2. T
Use Cases T uc = 3 P j =1 (nuc j )
uc j ) j = S = A =C : nu =n um b er
use cases; W uc =w eigh t
a use case. Use case's complexit y in terms
transactions p er U.C.
n um b er
analysis classes / U.C.
SLIDE 25 3. Unadjusted use case p
ts U U C P = T a + T uc 4. T ec hnical Complexit y
the Pro ject T C F = 0:6 + 0:01
P k =1 (V tf k )
tf k ) 13 =factors con tributing to complexit y (ho w dicult the system will b e to construct). TCF is similar to F unction P
ts. 5. Exp erience lev el
the p eople
the pro ject (The En vironmen tal F actor). E F = 1:4
P l =1 (V ef l )
ef l ) 8 =factors con tributing to eciency .
SLIDE 26 6. Use Case P
ts U C P = U U C P
C F
F 7. Pro ject Estimate E = U C P
R [MH] [MH]=man hour. E R
Rate [MH / UCP] 8. Dev elopmen t Time T D E V = E = N + T [W eeks] E
[MW]. MW=man w eeks. N
b er
p eople in the dev elopmen t team. T
time for w
an y team issues. Reference: Geri Sc hneider, Jason P . Win ters: \Applying Use Cases. A Practical Guide". Addison-W esley , 1998.
SLIDE 27 IX. Conclusion
eb Application Systems (W AS) reengineer and c hange business practices
eb sp ecic elemen ts
a mo deling tec hnique applicable for W AS are: W eb pages, h yp erlinks, their relationships to the bac k end elemen ts
the system
duct mo dels need to capture the execution
business logic in W eb pages
ts sp ecication and use cases use a series
translations to dene a design mo del used to directly driv e the co de implemen tation
decisions should b e based
scien tic metho ds instead
the ad-ho c
mo deling and estimation tec hniques and algorithms based
use cases can b e used b y adding fron t-ends to the b est existing cost mo dels
in terconnected mo dels for soft w are dev elopmen t are the b est approac hes for W AS.
SLIDE 28 References [1] R UP99: R ational Unie d Pr
ess. Rational Soft w are, 1999. [2] A.J.Stoica, F ac ets
the Softwar e Development R epr esente d by Mo del Systems: A nalysis and Enhanc ement. 14th In ternational F
COCOMO/SCM, 1999. [3] B.Bo ehm and D.P
Conc eptual Mo deling Chal lenges for Mo del-Base d A r chite cting and Softwar e Engine ering. USC Cen ter for Soft w are Engineering, 1998. [4] B.Bo ehm and D.P
Esc aping the Softwar e T ar Pit: Mo del Clashes and How to A void Them. A CM Soft w are Engineering Notes, Jan., 1999. [5] J. G.Sc hneider, Applying Use Cases. A Pr actic al Guide. Addison-W esley Ob ject T ec hnology Series, 1998. [6] H.Maruy ama, K.T am ura, and N.Uramoto, XML and Java. Developing Web Applic ations. Addison-W esley , 1999. [7] J.Conallen, Building Web Applic ations with UML. Addison-W esley Ob ject T ec hnology Series, 2000.
SLIDE 29 [8] R.Kalak
and M.Robinson, e-Business. Addison-W esley Information T ec hnology Series, 1999. [9] T.Quatrani, Visual Mo deling with R ational R
2000 and UML. Addison-W esley Ob ject T ec hnology Series, 2000.
