Model Driven Architecture

Transcription

1 IBM Software Group Model Driven Architecture The first (and last) step to an on demand business Geoff Hambrick Distinguished Engineer, ISSW Enablement Team

2 Model Driven Architecture Overview Four principles of MDA 3 : 1. Models expressed in a well-defined notation are key to understanding enterprise-scale systems 2. Transformations between models enable organization into a layered architectural framework 3. Metamodels facilitate meaningful integration and transformation, and are the basis for tooling 4. Standards provide openness to consumers and foster competition among vendors

3 OMG vision: Managing IT Complexity using Model Driven Architecture (MDA) TM An integration of best practices in Modeling, Middleware, Metadata, and Software Architecture Model Driven Platform Independent Models (PIM) Technology or (increasingly) Business Models Platform Specific Models (PSM) - J2EE,.Net, SQL Mappings : PIM<->PIM, PSM<->PSM, PIM<->PSM Applies across the software life cycle MDA is a framework, process and a set of standards Source: OMG Key Benefits Improved Productivity for Architects, Designers, Developers and Administrators Lower cost of Application Development and Management Enhanced Portability and Interoperability Business Models and Technologies evolve at their own pace on platform(s) of choice

4 Platform specific model UML Take a moment to assess this class diagram: 獺 ttpservlet Order Details Servlet 獷 JB Home Open Order Home 獷 JB Object Open Order + open ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( ) 獷 JB Session Bean Open Order Bean Customer - Open Order - Orders Order Key 0..1 Line Item - Items Order 獷 JB Entity Bean Order Bean 獷 JB Local Home Order Home 1 - Product Product + 獵 ustomer? getcustomer ( ) + 獵 ollection? getitems ( ) + 玈 tring? getstatus ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( )

5 Platform specific model UML Good: shows the classes you will need to build 獺 ttpservlet Order Details Servlet 獷 JB Home Open Order Home 獷 JB Object Open Order + open ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( ) 獷 JB Session Bean Open Order Bean Customer - Open Order - Orders Order Key 0..1 Line Item - Items Order 獷 JB Entity Bean Order Bean 獷 JB Local Home Order Home 1 - Product Product + 獵 ustomer? getcustomer ( ) + 獵 ollection? getitems ( ) + 玈 tring? getstatus ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( )

6 Platform specific model UML Good: implies use of best practices 獺 ttpservlet Order Details Servlet 獷 JB Home Open Order Home 獷 JB Object Open Order 獷 JB Session Bean Open Order Bean + open ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( ) Customer - Open Order - Orders Order Key 0..1 Line Item - Items Order 獷 JB Entity Bean Order Bean 獷 JB Local Home Order Home 1 - Product Product + 獵 ustomer? getcustomer ( ) + 獵 ollection? getitems ( ) + 玈 tring? getstatus ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( )

7 Platform specific model UML Bad: cannot tell the business purpose of this model 獺 ttpservlet Order Details Servlet 獷 JB Home Open Order Home 獷 JB Object Open Order + open ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( ) 獷 JB Session Bean Open Order Bean Customer - Open Order - Orders Order Key 0..1 Line Item - Items Order 獷 JB Entity Bean Order Bean 獷 JB Local Home Order Home 1 - Product Product + 獵 ustomer? getcustomer ( ) + 獵 ollection? getitems ( ) + 玈 tring? getstatus ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( )

8 Platform specific model UML Ugly: not enough information to implement methods 獺 ttpservlet Order Details Servlet 獷 JB Home Open Order Home 獷 JB Object Open Order + open ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( ) 獷 JB Session Bean Open Order Bean Customer - Open Order - Orders Order Key 0..1 Line Item - Items Order 獷 JB Entity Bean Order Bean 獷 JB Local Home Order Home 1 - Product Product + 獵 ustomer? getcustomer ( ) + 獵 ollection? getitems ( ) + 玈 tring? getstatus ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( )

9 Platform specific model UML Summary of my assessment: shows an end-to-end set of Java objects to build: 1 Servlet 1 Remote EJB Home, 1 EJB Remote Interface, 1 Session EJB 1 Local EJB Home, 1 Key, 1 Local EJB Interface, 1 Entity EJB implies use of some key best practices: separate the UI (Servlet) from the business logic (EJBs) use a session EJB as a façade in front of entity EJBs use CMRs with entity EJBs to enable container to optimize? no tie to the business process being implemented: the methods shown on the Open Order Bean (business logic) the doget() and dopost() methods on Order Details Servlet (UI) not enough information to code the business logic: how does the Order EJB get instantiated in the Session? under what conditions can the methods be invoked in the Entity?

10 Platform specific model Java code Take a moment to assess this code package com.mycompany.onlinemall.business.objects; public class OrderBean extends javax.ejb.entitybean { public abstract Customer getcustomer(); public abstract void setcustomer(customer value); public abstract Collection getitems(); public abstract void setitems(collection value); public abstract String getstatus(); public abstract void setstatus(string value); public void submit() throws OrderNotOpen, UserNotCustomer, NoLineItems { String userid = myentityctx.getcalleridentity().getname(); if (!getstatus.equals(order_status_open)) throw new OrderNotOpen(getPrimaryKey()); if (!getcustomer().getuserid().equals(userid)) throw new UserNotCustomer(user, getprimarykey()); if (getitems().getsize() == 0) throw new NoLineItems(getPrimaryKey()); setstatus(order_status_submitted); // Other methods will follow over time

11 Platform specific model Java code Good: this component is actually complete package com.mycompany.onlinemall.business.objects; public class OrderBean extends javax.ejb.entitybean { public abstract Customer getcustomer(); public abstract void setcustomer(customer value); public abstract Collection getitems(); public abstract void setitems(collection value); public abstract String getstatus(); public abstract void setstatus(string value); public void submit() throws OrderNotOpen, UserNotCustomer, NoLineItems { String userid = myentityctx.getcalleridentity().getname(); if (!getstatus.equals(order_status_open)) throw new OrderNotOpen(getPrimaryKey()); if (!getcustomer().getuserid().equals(userid)) throw new UserNotCustomer(user, getprimarykey()); if (getitems().getsize() == 0) throw new NoLineItems(getPrimaryKey()); setstatus(order_status_submitted); // Other methods will follow over time

12 Platform specific model Java code Good: dependencies are clearly shown package com.mycompany.onlinemall.business.objects; public class OrderBean extends javax.ejb.entitybean { public abstract Customer getcustomer(); public abstract void setcustomer(customer value); public abstract Collection getitems(); public abstract void setitems(collection value); public abstract String getstatus(); public abstract void setstatus(string value); public void submit() throws OrderNotOpen, UserNotCustomer, NoLineItems { String userid = myentityctx.getcalleridentity().getname(); if (!getstatus.equals(order_status_open)) throw new OrderNotOpen(getPrimaryKey()); if (!getcustomer().getuserid().equals(userid)) throw new UserNotCustomer(user, getprimarykey()); if (getitems().getsize() == 0) throw new NoLineItems(getPrimaryKey()); setstatus(order_status_submitted); // Other methods will follow over time

13 Platform specific model Java code Good: you can reverse engineer some of the process package com.mycompany.onlinemall.business.objects; public class OrderBean extends javax.ejb.entitybean { public abstract Customer getcustomer(); public abstract void setcustomer(customer value); public abstract Collection getitems(); public abstract void setitems(collection value); public abstract String getstatus(); public abstract void setstatus(string value); public void submit() throws OrderNotOpen, UserNotCustomer, NoLineItems { String userid = myentityctx.getcalleridentity().getname(); if (!getstatus.equals(order_status_open)) throw new OrderNotOpen(getPrimaryKey()); if (!getcustomer().getuserid().equals(userid)) throw new UserNotCustomer(user, getprimarykey()); if (getitems().getsize() == 0) throw new NoLineItems(getPrimaryKey()); setstatus(order_status_submitted); // Other methods will follow over time

14 Platform specific model Java code Bad: still don t know the business process context package com.mycompany.onlinemall.business.objects; public class OrderBean extends javax.ejb.entitybean { public abstract Customer getcustomer(); public abstract void setcustomer(customer value); public abstract Collection getitems(); public abstract void setitems(collection value); public abstract String getstatus(); public abstract void setstatus(string value); public void submit() throws OrderNotOpen, UserNotCustomer, NoLineItems { String userid = myentityctx.getcalleridentity().getname(); if (!getstatus.equals(order_status_open)) throw new OrderNotOpen(getPrimaryKey()); if (!getcustomer().getuserid().equals(userid)) throw new UserNotCustomer(user, getprimarykey()); if (getitems().getsize() == 0) throw new NoLineItems(getPrimaryKey()); setstatus(order_status_submitted); // Other methods will follow over time

15 Platform specific model Java code Ugly: forces use of a specific language and platform package com.mycompany.onlinemall.business.objects; public class OrderBean extends javax.ejb.entitybean { public abstract Customer getcustomer(); public abstract void setcustomer(customer value); public abstract Collection getitems(); public abstract void setitems(collection value); public abstract String getstatus(); public abstract void setstatus(string value); public void submit() throws OrderNotOpen, UserNotCustomer, NoLineItems { String userid = myentityctx.getcalleridentity().getname(); if (!getstatus.equals(order_status_open)) throw new OrderNotOpen(getPrimaryKey()); if (!getcustomer().getuserid().equals(userid)) throw new UserNotCustomer(user, getprimarykey()); if (getitems().getsize() == 0) throw new NoLineItems(getPrimaryKey()); setstatus(order_status_submitted); // Other methods will follow over time

16 Platform specific model Java code Summary of my assessment: this code is actually complete and follows best practices: order logic in a method to minimize resource utilizations use CMRs to enable container to optimize access defines other Java objects you need to build: 1 Local EJB Home, 1 Key, 1 Local EJB Interface can reverse engineer some of the business process: the Order Bean submit() method (with more to follow)? does not tell you the full business context: what is the process lifecycle being supported? what other methods are likely to get added over time? forces use of a specific platform, language and approach: Java/J2EE platform versus COBOL/CICS or VB/.NET it is OK to have logic in entity EJB versus all in a session EJB

17 Platform independent business model Example order lifecycle: open(customer):[customer has no open order] Customer assign(packer) Packer cancel() Open submit():[line items.has elements] add line item(product, quantity):[quantity.non zero] Cancelled Submitted pack item(inventory, quantity):[quantity.non zero && quantity.less or equal(inventory.on hand) && items(inventory.product).left] ship(shipper):[packed items.has elements && shipper specified] [> 0] [== 0] Completed line items.sum.left purge() Marketer

18 Platform independent business model Example pseudo code for add line item: status check of order not needed due to state in the lifecycle user id check of order customer is not needed due to owner of state product id check is not needed due to product reference being passed in quantity check for non zero not needed due to guard add line item (Product.ref product, Integer.val quantity) { Line Item.ref line item = line items.retrieve(product); if (line item exists) { Integer.val new quantity = line item.quantity + quantity; if (new quantity.less or equal(0)) line items.destroy(product); else line item.quantity = new quantity; else { line items.create(line Item.create(product, quantity));

19 Platform independent business model Example class diagram for objects needed in open state: only those required to support inputs, guards, actions, conditions and outputs of add Iine item(), submit(), and cancel() transitions assume that the open state in the order lifecycle has read only transitions that support access to any of this data for purposes of depth first design, assume that related objects support CRUD methods as needed (create, retrieve, update and destroy) Customer [Active] - open order 0..1 Order [Open] + name : String + «Key» id : Integer 1 + «Key» id : Integer + total : Integer = line items.sum.amount Product [Cataloged] + «Key» sku : Integer + description : String + price : Integer 1 -@product Line Item + quantity : Integer + amount : Integer = product.price quantity

20 Platform independent business model Example class diagram for open order submitted state: Customer [Active] + name : String + 獽 ey? id : Integer 1 Order [Submitted] + 獽 ey? id : Integer + total : Integer = line items.sum.amount 1.. Shipment + 獽 ey? id : Integer + tracking number : String 0..1 Shipper [Qualified] + name : String + 獽 ey? id : Integer Product [Cataloged] + 獽 ey? sku : Integer + description : String + price : Integer 1 1 Line Item + quantity : Integer [>0] + amount : Integer = product.price quantity + shipped : Integer = packed items.sum.quantity + left : Integer = quantity - shipped 1 Packed Item + quantity : Integer 1 Inventory + 獽 ey? aisle : String + 獽 ey? bin : Integer + on hand : Integer Packer [Active] + name : String + 獽 ey? id : Integer 0..1 Warehouse + 獽 ey? name : String Note the differences in cardinalities

21 Platform independent business model Example lifecycle model for a customer record: [not ok] Customer customer management [ok] {credit check /create (key) Registered activate(key) Active [last activity > 1 year] order management release Credit Hold Credit Manager reactivate Inactive Marketer Address Customer [Active] Credit Card + «String» street 1 + «String» street 2 + «String» city + «String» state + «String» postal 1..n + «Key» id + «String» name + «String» password + «String» challenge + «String» 1..n + «String» company + «String» number + «String» name on card + «Month-Year» expires + «String» comment - open order 0..1 Order

22 Building a solution using MDA step 1 Gather the high level requirements for the system Data stored on web farm with browser client open(customer):[customer has no open order] Customer Data stored on mainframe with fat client GUI assign(packer) Packer cancel() Open submit():[line items.has elements] add line item(product, quantity):[quantity.non zero] Cancelled Submitted pack item(inventory, quantity):[quantity.non zero && quantity.less or equal(inventory.on hand) && items(inventory.product).left] ship(shipper):[packed items.has elements && shipper specified] [> 0] [== 0] Completed Data stored offline with batch submit & browser read/print line items.sum.left purge() Marketer

23 Building a solution using MDA step 2a Synthesize the UI from Order and Web design models previous (customer, first):[!first] Customer Home next (customer, last):[!last] (customer) Product Catalog (customer) Order Management (customer) Order Status add line item (customer, product, qty):[qty!= 0]/{add item(customer, product, qty) (customer, order, product, qty) modify line item (customer, product, qty):[order.status='open' && qty >=0]/{customer.open order.lineitem( product).quantity = qty (customer, order, product, qty) (customer):[customer.openorder!= null] (customer, order):[order.customer=customer] add order (customer):[customer.open Order=null] cancel cancel:[customer.open Order.status='Open'] Order Details ok:/{create(customer) (customer, order) Confirm Add cancel cancel ok:/{submit(customer) Confirm Cancel ok:/{cancel(customer) submit:[customer.open Order.status='Open'] Confirm Submit

24 Building a solution using MDA step 2a Does this model completely specify the UI? previous (customer, first):[!first] Customer Home next (customer, last):[!last] (customer) Product Catalog (customer) Order Management (customer) Order Status add line item (customer, product, qty):[qty!= 0]/{add item(customer, product, qty) (customer, order, product, qty) modify line item (customer, product, qty):[order.status='open' && qty >=0]/{customer.open order.lineitem( product).quantity = qty (customer, order, product, qty) (customer):[customer.openorder!= null] (customer, order):[order.customer=customer] add order (customer):[customer.open Order=null] cancel cancel:[customer.open Order.status='Open'] Order Details ok:/{create(customer) (customer, order) Confirm Add cancel cancel ok:/{submit(customer) Confirm Cancel ok:/{cancel(customer) submit:[customer.open Order.status='Open'] Confirm Submit

25 Building a solution using MDA step 2b Specify the visible data for each state in the UI Customer Home Data + «int» id + «String» name + «int» order pending Product Catalog Data Order Management Data Order Status Data Product Data + «int» sku + «String» description + «int» price Order Details Data Detail Item Data + «int» product + «String» description + «int» quantity + «int» price + «int» amount Order Header Data + «int» id + «String» status + «int» total

26 Building a solution using MDA step 2b Where did this data come from? Customer Home Data + «int» id + «String» name + «int» order pending Product Catalog Data Order Management Data Order Status Data Product Data + «int» sku + «String» description + «int» price Order Details Data Detail Item Data + «int» product + «String» description + «int» quantity + «int» price + «int» amount Order Header Data + «int» id + «String» status + «int» total

27 Building a solution using MDA step 2b Visible data ultimately derives from the business objects Customer [Active] - open order 0..1 Order [Open] + name : String + «Key» id : Integer 1 + «Key» id : Integer + total : Integer = line items.sum.amount Product [Cataloged] + «Key» sku : Integer + description : String + price : Integer 1 -@product Line Item + quantity : Integer + amount : Integer = product.price quantity

28 Building a solution using MDA step 3a Synthesize Order-Web and J2EE design models 獺 ttpservlet Order Details Servlet 獷 JB Home Open Order Home 獷 JB Object Open Order 獷 JB Session Bean Open Order Bean + open ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( ) Customer - Open Order - Orders Order Key 0..1 Line Item - Items Order 獷 JB Entity Bean Order Bean 獷 JB Local Home Order Home 1 - Product Product + 獵 ustomer? getcustomer ( ) + 獵 ollection? getitems ( ) + 玈 tring? getstatus ( ) + submit ( ) + cancel ( ) + add line item ( ) + modify line item ( )

29 Building a solution using MDA step 3b Transform J2EE-Order-Web design model into code package com.mycompany.onlinemall.business.objects; public class OrderBean extends javax.ejb.entitybean { public abstract Customer getcustomer(); public abstract void setcustomer(customer value); public abstract Collection getitems(); public abstract void setitems(collection value); public abstract String getstatus(); public abstract void setstatus(string value); public void submit() throws OrderNotOpen, UserNotCustomer, NoLineItems { String userid = myentityctx.getcalleridentity().getname(); if (!getstatus.equals(order_status_open)) throw new OrderNotOpen(getPrimaryKey()); if (!getcustomer().getuserid().equals(userid)) throw new UserNotCustomer(user, getprimarykey()); if (getitems().getsize() == 0) throw new NoLineItems(getPrimaryKey()); setstatus(order_status_submitted); // Other method code follows

30 How does Model Driven Architecture help? A Rational Unified Process view: Phase Inception Elaboration Construction Role Pre MDA Artifact After MDA Architect Analyst Developer Deployer Candidate architecture Requirements specifications Executable application Transition Production application Transformations Model Schemas Templates Exemplars Building transforms should become an essential part of the end-to-end process

31 How does Model Driven Architecture help? Over time, the amount of manual coding decreases % 0 SRV JSP CT EJB MDB WS % Manual coding required WBI BPC RSA # Transforms developed

32 Questions?