E133 Moving PB Apps to a distributed platform

1
E133Moving PB Apps to a distributed platform

• Bill Green
• VP Emerging Technologies
• Power3
• wgreen_at_power3.com

2
Marketing

• Customized Training
• PowerBuilder, Internet, Software Quality
  Assurance
• Hands-On Classroom training
• On-Site Mentoring
• Component Development Practice
• Software Quality Practice

3
Objective for today

• Talk about what Sybase offers today in terms of
  distributed computing development
• Walkthrough a typical PFC-based PowerBuilder
  application transition from 2-tier client-server
  to n-tier client-server

4
Development Scenarios today
5
Whats needed today?

• We still need good 2-tier client-server tools
• We need good HTML and Java development tools
• We need a good web-server so that browser based
  applications can be conversational
• Most of all we need a good application server

6
Developing with PowerJ
Applets
Java Applications
JavaScript
JSP, Servlets, EJB
Java in the Database Exec Java Classes Col Java
Classes
7
Developing with PowerBuilder
HTML Pages
PB Applications
DynaScript
PowerBuilder NVOs
8
Distributed Computing Development

• Its an arduous task to scan through an
  application looking for business logic
• Try to use whatever automated tools possible to
  perform this analysis
• There are three approaches possible When youre
  faced with a non-partitioned application with the
  task of partitioning it, the most common reaction
  is

Who wrote this stuff?
9
Approaches

• You can reverse engineer the application
• You can scan for business logic and extract it to
  business objects
• Wait for business need to target an area of
  functionality

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Ideal Approach

• You can reverse engineer the application
• You can scan for business logic and extract it to
  business objects
• Wait for business need to target an area of
  functionality

11
Unfortunately

• Real World We need this done in 6 weeks
• The real world dictates what approach will be
  taken rather than a sense of what will work best

12
Reverse Engineering

• No tools available to do this automatically,
  but...
• Rational Rose/PB will reverse engineer
• HOW will reverse engineer
• PowerDesigner will reverse engineer
• These tools can only define classes based on your
  existing objects - Often not very useful as your
  design will change
• Useful as documentation of your existing
  application
• If application is well-partitioned already, these
  tools can reduce the amount of time needed

13
Application Scanning

• Time consuming
• Prone to error
• Very few tools available to assist
• Most probable route chosen in the real world - Do
  everything at once, and do it now!

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Wait for the business need

• Targeted application scanning
• Working only with the code affected by the
  business need
• Follows the same steps as scanning
• Best Approach for existing PB apps - Almost never
  the route chosen

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Directive from Marketing

• Get our Sales application to the web! Now!!

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The existing system

• A simple Sales Order system
• Based on the PFC
• Sales Order Entry w_sales_order
• Customer Maintenance w_Customer

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The Sales Order System
Place an Order
Evaluate Sales Order
Calculate Discount
Complete the Sale
Create the Order
18
Analyze the existing system

• Scan the existing code
• Remember, youre looking for Business Logic that
  should be partitioned
• Review
• Where do you look?

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What to look for

• Logic imbedded in datawindow objects
• Evaluation Rules
• Grouping rules
• Calculations
• Expressions
• Logic imbedded in datawindow controls
• Click, ItemChanged, EditChanged most prevalent
• Save cycle logic most important, location
  undetermined
• Logic imbedded in Windows and other objects
• Save Cycles most obvious point to look

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Review Findings
w_sales_order
dw_salesorder pfc_preupdate Discount
Logic pfc_preinsertrow New Cust ID
SOS-1
In DataWindow Code
dw_sales_order_items itemchanged Get Price
In DataWindow Object Expressions
d_sales_order_items (DataObject) Default Ship
Date Today
Also look in Window events, called service
objects etc
Behind Buttons
Discount Logic
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Analyze the existing system

• Discount Code Calculation is implemented in
  different areas and in different ways
• preupdate event
• Coded behind a button
• potentially, elsewhere
• Some business rules are implemented incorrectly
• Default Ship-date Today()
• Should be based on location
• We also note that several business rules arent
  implemented at all
• Order not checked for Order Items
• Diagnosis Unhealthy!

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What to do when you find logic

• Document the logic as close to a method or rule
  as possible
• Group and sub-group the methods and rules into
  logical groups
• Discount Code Calculation Sales Orders
• Ship-Date Calculation Sales Order Items
• Product Price Product
• Compare with the original function specs for the
  system and discuss with users
• Design and code new business objects

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Design the business objects

• Itemize the Use Cases that will apply
• If you are not familiar with Use Cases, think in
  terms of a business process
• Itemize the rules that will apply
• Determine which rules will apply locally
• What is affected by user entered data and is not
  dependent on other data
• Categorize the rules and Use Cases into groups
• These groups will become your Business Objects
• Build Class Definitions for your business objects

24
Design Techniques for components

• Remember youre designing ultimately to be
  distributable so keep in mind
• Create your NEW NVOs as Jaguar Components
• If you already have Business Logic coded in
  NVOs, check
• Add an Activate event (pbm_ComponentActivate) -
  Copy any constructor code here
• Same for Deactivate and copy Destructor code
• Replace any references to DataStore with a
  userobject version of a datastore

25
Review Partitioned Logic
w_sales_order
All Sales Order logic goes in the Sales Order
Object
n_bo_salesorder of_calculatediscount() of_get_next
OrderID()
All of this currently runs on the client...
26
Review Partitioned Logic
w_sales_order
n_bo_salesorder of_calc_discount() of_get_nextOrde
rID()
Sales Order Item logic goes in the Sales Order
Items object
n_bo_salesorderitems of_calc_shipdate()
All of this currently runs on the client...
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Review Partitioned Logic
w_sales_order
n_bo_salesorder of_calc_discount() of_get_nextOrde
rID()
n_bo_salesorderitems of_calc_shipdate()
Functions relating to Product go in the Product
object
n_bo_product of_get_productprice()
All of this currently runs on the client...
28
Review Partitioned Logic - Local Rules
w_sales_order
n_bo_salesorder of_calc_discount() of_get_nextOrde
rID()
n_bo_salesorderitems of_calc_shipdate()
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Unit Price gt
5.00
n_bo_product of_get_productprice()
All of this currently runs on the client...
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What are Local Rules?

• Local rules are those rules which apply to your
  data at the point of entry
• Examples
• Column Initialization (Local Only)
• Setup the initial value for a column (Initial
  Value)
• Column Validation (Local Only)
• Entered value is valid (Validation Rule)
• Notification (Local Only)
• Highlight cells for notification
• Data Validation (Local Remote)
• Data entered meets specified business
  requirements

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Column Initial Value setup

• dw_sales_order
• PostInsert event
• OrderDate set to today

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Column/Data Validation rule

• Sales Order Items
• Unit Price rule
• Unit price may not be less than 5.00

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When to Use Local Rules

• When rules need to be applied at point of entry
• When data required is contained within the cell
  or row being edited
• Local Rules should not require processing beyond
  the scope of the local object

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How do you create Local Rules

• Local Rules objects is an NVO just like any other
  service object
• example n_bo_lr_salesorderitems
• Implemented as a service in either the client or
  server object
• Rules are built through a function that is
  defined to do 2 things
• Generate a Modify() statement to implement the
  rule in a datawindow/datastore
• Create an Evaluation statement that can be
  executed by passing parameters

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Now we determine separation

• Decide what will run on the server and what will
  run on the client
• Anything that runs on the client is what would be
  needed to replicate the functionality in a
  different front-end (eg Internet)
• Remember that Local Rules should also be
  implemented on the Server for clients that do not
  have PBs client-side validation
  capabilities(HTML)

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Partitioning Logic - Location
w_sales_order
This should go on the server
n_bo_salesorder of_calculatediscount() of_get_next
OrderID()
n_bo_salesorderitems of_calc_shipdate()
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Unit Price gt
5.00
n_bo_product of_getproductprice()
PBL Sales_order_NVOs
All of this currently runs on the client...
36
Partitioning Logic - Location
w_sales_order
n_bo_salesorder of_calculatediscount() of_get_next
OrderID()
This should go on the server
n_bo_salesorderitems of_calc_shipdate()
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Unit Price gt
5.00
n_bo_product of_getproductprice()
PBL Sales_order_NVOs
All of this currently runs on the client...
37
Partitioning Logic - Location
w_sales_order
n_bo_salesorder of_calculatediscount() of_get_next
OrderID()
n_bo_salesorderitems of_calc_shipdate()
This should go on the server
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Unit Price gt
5.00
n_bo_product of_getproductprice()
PBL Sales_order_NVOs
All of this currently runs on the client...
38
Partitioning Logic - Location
w_sales_order
n_bo_salesorder of_calculatediscount() of_get_next
OrderID()
n_bo_salesorderitems of_calc_shipdate()
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Unit Price gt
5.00
n_bo_product of_getproductprice()
Where should Local Rules go?
All of this currently runs on the client...
39
Partitioning Logic - Location
w_sales_order
n_bo_salesorder of_calculatediscount() of_get_next
OrderID()
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Order Item
Quantity gt 0
n_bo_salesorderitems of_calc_shipdate()
n_bo_product of_getproductprice()
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Order Item
Quantity gt 0
On both sides Even better if stored on the server
and downloaded to the client
All of this currently runs on the client...
40
Partitioning Logic - Location
w_sales_order
n_bo_salesorder of_calculatediscount() of_get_next
OrderID()
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Order Item
Quantity gt 0
n_bo_salesorderitems of_calc_shipdate()
n_bo_product of_getproductprice()
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Order Item
Quantity gt 0
This should NOT go on the server. Why?
All of this currently runs on the client...
41
We separate the items accordingly
w_sales_order
n_bo_salesorder of_calculatediscount() of_get_next
OrderID()
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Order Item
Quantity gt 0
n_bo_salesorderitems of_calc_shipdate()
Local validation rules n_bo_lr_salesorders Order
Date Today n_bo_lr_salesorderitems Unit Price gt
5.00
n_bo_product of_getproductprice()
This runs on the client
This runs on the server
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What else would we separate?
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Data Access Components

• Get data from DB
• Pass data to client
• Monitor data changes
• Apply business rules
• Apply updates

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Distributed Data Access

• Wed like to insulate our data access for
  customer
• Create a Customer Business Object
• Provide Methods for retrieving customer(s)
• Provide Method for sending updates
• NoteThis object is being designed with
  state.It keeps customer information in memory
  while the client performs work

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Data Access and Synchronization

• GetFullState( blob, cookie )
• Grabs all info from one dw to be replicated
  elsewhere.
• SetFullState( blob )
• Puts info from a dw into another
• GetStateStatus( cookie )
• Used to create a changes cookie
• GetChanges( blob )
• use the GetStateStatus cookie to determine if
  changes are likely to succeed
• Generates a changeblob for use in SetChanges
• SetChanges
• Applies changes

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Passing Data
w_customer
n_bo_customer

of_GetCustomer()

This runs on the client
This runs on the server
47
Passing Data
w_customer
n_bo_customer

1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
of_GetCustomer()
Retrieve()

This runs on the client
This runs on the server
48
Passing Data (GetFullState)
w_customer
n_bo_customer
1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
of_GetCustomer()
Retrieve() GetFullState()

This runs on the client
This runs on the server
49
Passing Data (SetFullState)
w_customer
n_bo_customer
1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
of_GetCustomer()
Retrieve() GetFullState()

1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
SetFullState()
This runs on the client
This runs on the server
50
Passing Data (Data Changes)
w_customer
n_bo_customer
1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
of_GetCustomer()
Retrieve() GetFullState()

1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
1 ABC Co. IL 2 XYZ Inc. NJ 3 Jones Inc. NC
SetFullState()
This runs on the client
This runs on the server
51
Passing Data (GetChanges)
w_customer
n_bo_customer
1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
of_GetCustomer()
Retrieve() GetFullState()

1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
1 ABC Co. IL 2 XYZ Inc. NJ 3 Jones Inc. NC
SetFullState()
GetChanges()
This runs on the client
This runs on the server
52
Passing Data (SetChanges)
w_customer
n_bo_customer
1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
1 ABC Co. IL 2 XYZ Inc. NJ 3 Jones Inc. NC
of_GetCustomer()
Retrieve() GetFullState()

1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
1 ABC Co. IL 2 XYZ Inc. NJ 3 Jones Inc. NC
SetFullState()
of_UpdateCustomer()
SetChanges()
GetChanges()
This runs on the client
This runs on the server
53
Passing Data (SetChanges)
w_customer
n_bo_customer
1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
1 ABC Co. IL 2 XYZ Inc. NJ 3 Jones Inc. NC
of_GetCustomer()
Retrieve() GetFullState()

1 ABC Co. IL 2 XYZ Inc. GA 3 Jones Inc. NC
1 ABC Co. IL 2 XYZ Inc. NJ 3 Jones Inc. NC
SetFullState()
of_UpdateCustomer()
SetChanges() Update()
GetChanges()
Update Result returned to client
This runs on the client
This runs on the server
54
OK, so we have components. Now what?

• Deploy the component to Jaguar
• Change the Client Application to access the
  Jaguar Component instead of the local components

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Deploy the component to Jaguar

• Create a Jaguar Component Project using the
  Project Component Wizard

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Prepare the client - stage 1

• Create Proxies of the Jaguar Components
• Use the Jaguar Proxy Wizard
• Target the application library for the proxies
• Remove the actual component library from the
  search path

57
Prepare the client - Stage 2

• Connect the application to the Jaguar Server
• Use the wizard to create a customized connection
  object

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Prepare the client - Stage 3

• Connect to the Jag Server
• Create the component using CreateInstance()

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Prepare the client - Stage 4

• Access Component Methods

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Accessing from a client application
PB native NVOs residing in Jaguar
n_bo_customer of_GetCustomer() of_GetCustomers() o
f_UpdateCustomer()
PB Client
Connection ConnectToServer()
n_bo_salesorders of_getnextorderid() of_calcdiscou
nt() of_insertsalesorder()
Proxy CreateInstance() n_bo_customer of_GetCustome
r() of_GetCustomers() of_UpdateCustomer()
61
Accessing from the Web

• Natively via HTML
• Using PowerDynamo
• Using JSPs

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Hardware Structure
Typical
63
Needs Issues

• Servlet Class Library from www.servlets.com
  contains File Upload class
• Create a Servlet that will accept the HTML
  request, call the File Upload and then connect
  to, and call EAServer

• We need something that can accept Files from a
  browser
• We need a class that can call an EAServer
  Component

64
Direct Web Access

• What if we wanted to access our PowerBuilder
  component directly from an HTML page?
• Normally, you cant. But if you use a servlet as
  the intermediary.
• Introducing JAWS

65
Jaguar Agent for Web Servers

• JAWS can be downloaded from the Sybase Website.
  It is a Servlet that provides HTTP access to your
  PowerBuilder components

66
Java Server Pages (JSP)

• Java Server Pages are sort of a mutated
  combination of HTML and Servlets. A JSP page is
  an HTML page with some special tags that allow
  you to use data much the same way you would in a
  servlet. You can also call Java code directly.
• A JSP is compiled into a Servlet and is run on
  the server.
• So, a JSP Page is a server-side HTML page that
  can speak Java.

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Java Server Pages (JSP)

• When are JSPs useful?
• JSPs are HTML pages that imbed Java. This means
  you can use a language like Java to build
  structured HTML pages, reducing the amount of
  code dramatically.
• If you think about it, JSPs are the
  implementation of application partitioning.
  Presentation is done with HTML. Logic is done in
  Java.
• Because a significant portion of your code is in
  Java, it is reusable, improving maintenance.

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JSPs are HTML!!!!

• lthtmlgt
• ltheadgtlttitlegtCustomer List lt/titlegtlt/headgt
• ltbodygt

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Special Tags add new capabilities

• lt_at_ page import"org.omg.CORBA.ORB" gt
• lt_at_ page import"org.omg.CosNaming.NamingContext"
  gt
• lt_at_ page import"org.omg.CosNaming.NamingContextHe
  lper" gt
• lt_at_ page import"org.omg.CosNaming.NameComponent"
  gt
• lt_at_ page import"P3_Sales." gt

70
Some Java code sets things up

• lt
• String sz_action
• String sz_context
• String sz_browser
• sz_action (String)request.getParameter("obj_act
  ion")
• if ( sz_action null)
• sz_action ""
• sz_context (String)request.getParameter("obj_co
  ntext")
• if ( sz_context null)
• sz_context ""

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Then, prepare to connect and call

• bo_customer iCustomernull
• String sznew String("")
• java.util.Properties props new
  java.util.Properties()
• props.put("org.omg.CORBA.ORBClass",
  "com.sybase.CORBA.ORB")
• props.put("com.sybase.CORBA.NameServiceURL",
  "iiop//localhost9000")
• ORB orb ORB.init((String) null, props)

72
Try to Connect

• try
• NamingContext context NamingContextHelper.narr
  ow(orb.resolve_initial_references("NameService"))
  
• NameComponent name new NameComponent("P3_S
  ales/bo_customer", "")
• SessionManager.Factory factory
  SessionManager.FactoryHelper.narrow(context.resolv
  e(name))
• iCustomer bo_customerHelper.narrow(factory.cre
  ate("jagadmin",""))
• catch (org.omg.CosNaming.NamingContextPackage.Not
  Found aException)
• catch (org.omg.CosNaming.NamingContextPackage.Can
  notProceed aException)
• catch (org.omg.CosNaming.NamingContextPackage.Inv
  alidName aException)

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Execute your PB Function

• try
• sz iCustomer.of_getcustomers_html( )
• catch (Exception aException)

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Send the output back to the browser

• out.print( sz )

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End inline Java Code

• gt

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And, its still HTML

• lt/bodygt

77
Its a very small world

• lthtmlgt
• ltheadgtlttitlegtCustomer List lt/titlegtlt/headgt
• ltbodygt
• lt_at_ page import"org.omg.CORBA.ORB" gt
• lt_at_ page import"org.omg.CosNaming.NamingContext"
  gt
• lt_at_ page import"org.omg.CosNaming.NamingContextHe
  lper" gt
• lt_at_ page import"org.omg.CosNaming.NameComponent"
  gt
• lt_at_ page import"P3_Sales." gt
• lt
• String sz_action
• String sz_context
• String sz_browser
• sz_action (String)request.getParameter("obj_act
  ion")
• if ( sz_action null)
• sz_action ""

78
Third Party Software

• If you find software that performs a task for
  you, you can use it in EAServer, and you can
  interchange them
• EAServer supports Active-Xs and Java components
• Real World Example
• Image Processing solution used Active-X Single
  Threaded
• Changed over to multi-threaded Java class
• Changed Image Processing time from 6 minutes to
  12 seconds.
• Real World Example
• Needed Secure Socket connection to a TCP Server
• Active-Xs found did not give us the flexibility
  we wanted
• Wrote a Java class to perform SSL based
  communications
• Real World Example
• Needed access to MapQuest data from our
  application
• Used MapQuest Active-X control via OLE

79
EJBs

• PowerBuilder 8 can access EJBs directly
• PowerBuilder as a Client Application can access
  EJBs on non-Sybase Application Server (eg BEA
  WebLogic)
• Opens up a whole new world of software components
  that can be integrated together
• Is this really happening?
• Check out BEA Website for article on connecting
  PB Apps to WebLogic components. Apparently BEA
  thinks its happening.

80
Other

• There are some significant components already in
  EAServer that are written in Java. You can use
  these today and not learn a single Java
  instruction
• ThreadManager for Multi-Threaded components
• MessageService for Pub-Sub messaging
• Etc

81
Review

• We reviewed what J2EE was and where it was going
• We dug deeper into Servlets and JSPs and saw how
  they can be leveraged to provide Browser access
  to our components, be they Java or PB
• We reviewed that Java Stubs are necessary to talk
  to PowerBuilder from servlets or JSPs.

82
Conclusions

• Java is a little more difficult to learn than a
  lot of people are saying
• Java is not yet the programming worlds salvation
• Java does a lot of things in standard objects
  that PB doesnt have, especially in the world of
  the web
• PB does things that Java doesnt do, or do as
  well, such as client applications in general and
  Datawindows in particular
• A combination of the two makes for a Powerful cup
  o Joe

83
Sybase PowerBuilder and EA Server - A Real
Distributed Solution
Enterprise Application Server
84
Questions?

• More Info www.power3.com
• eMail Me wgreen_at_power3.com