Designing ServiceOriented Applications with CA Plex r6'1

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Designing Service-Oriented Applications with CA
Plex r6.1
Session Code ROB2
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Agenda

• Introducing Plex Services
• Why Service Connectors?
• Service Connector Modeling
• Implementing Service Connectors using WCF
• Windows Communication Foundation Defined
• Basic WCF Service Connector Implementation
• WCF Specific Service Connector Modeling
• Runtime
• WCF/Plex Runtime Architecture
• Plex Runtime Configuration
• N-tier Implementation
• Error Handling
• Client Coding
• An Introduction to Business Process Modeling
  (BPM)
• Best Practices
• Plex Application Development and Service Modeling
• Troubleshooting
• Summary
• Q A

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Why Service Connectors?

• Before SOA
• Monolithic Applications
• Ridged Business Processes
• Functional Duplication
• Proprietary Communications
• Maintenance Complexity
• Tight-coupling between application, services and
  platforms

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Why Service Connectors?

• After SOA
• Modularized Applications
• Flexible Business Processes
• Functional Reuse
• Standardized Communication
• Maintenance Simplification
• Loose-coupling between application, services and
  platforms

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Why Service Connectors?

• To expose Plex applications via reusable service
  interfaces that can be incorporated into business
  processes using industry standard distributed
  technologies.

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Service Connector Modeling

• Services
• Have explicit boundaries
• Are autonomous
• Share schema and contract
• Component-modeling, evolved

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Service Connector Modeling

• Reuse the existing Plex Object-model

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Service Connector Modeling

• New Service Connector Specific Triples
• PKG type SYS/ServiceConnector
• CDL service PKG
• Think of a Service Connector as The part of a
  Code Library you want to expose as a service
• Service Connectors created via Code Library
  Deployment Wizard Plug-ins
• First plug-in implemented WCF Service Generator

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Windows Communication Foundation Defined
.NET Remoting
ASMX
Interop with other platforms
Extensibility Location transparency
Attribute- Based Programming
Message- Oriented Programming
WS- Protocol Support
Enterprise Services
System.Messaging
WSE
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Windows Communication Foundation Defined

• A unified platform and programming model for
  building distributed systems, with a focus on
• Interoperability
• Can work with most existing .NET distributed
  technologies
• Good support for WS- protocols for
  cross-platform iiop
• Service-orientation
• Explicit boundaries
• Autonomous services
• Share only schema and contract

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Windows Communication Foundation Defined

• Endpoint consists of three parts
• Address Where is the service located
• Contract What does the service offer?
• Binding How do we communicate with the service?
• Combined they form the Service Contract

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Basic WCF Service Connector Implementation
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Basic WCF Service Connector Implementation

• Only one specific triple needed
• FNC language SYS/C
• All other options defined during generation

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Basic WCF Service Connector Implementation

• What do you end up with?
• Optional service host support files

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WCF Specific Service Connector Modeling

• Interface modeling for the Where and How of the
  endpoint (What is tied to Function)

MTOM (Message Transport Optimization Mechanism)
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WCF Specific Service Connector Modeling

• Use a new triple to set the hosting type
• PKG service host type SYS

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Runtime Architecture
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Runtime Configuration

• Use any .config file that contains Plex .NET
  configuration sections
• Edit directly from the WCF Services Plug-in
• Dont Forget to Save!

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N-tier Support

• Which Server?
• Configure via Plex .config file

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Error Handling

• If an exception occurs in the Plex .NET Runtime
• Exception specifics should not be passed back to
  clients Exception Shielding
• Any exceptions should be passed back to the
  client via a known interface Fault Contract
• The service should be left in a known state after
  the exception has occurred

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Error Handling Part 1In the Service Layer

• Plex implements a custom Fault Contract called
  PlexRuntimeException
• Message Error message from the Plex .NET Runtime
  (String)
• CallStatus Did the call work? (Boolean)
• ReturnedStatus Any programmatic Returning status
  set before the error occurred (String)
• Wrap all operation calls in a try/catch block to
  monitor for this error (more on this later)

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Error Handling Part 2In the Plex .NET Runtime

• WCF Services use standard Plex .NET Logging
• FlatText logs created in standard log folder

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Client Coding

• Clients use a proxy to access running WCF
  Service Client Stub
• Create stubs for .NET client applications using
• Service Model Metadata Utility Tool (Svcutil.exe)
• Visual Studio 2008 Add Service Reference

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Client Coding

• Create the client stub instance
• // Create an instance of the WCF Service via the
  client stub.
• OrderClient myOrderClient new OrderClient()
• You might have to specify the endpoint you want
  to use
• // Create an instance of the WCF Service via the
  client stub.
• OrderClient myOrderClient new
  OrderClient("OrderWebEndpoint")

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Client Coding

• Set Input Parameters
• // Create the Variable DataContracts classes
  contained within the
• // Input Variable Group.
• HeaderBlockFetch_Input._Control control new
  HeaderBlockFetch_Input._Control()
• HeaderBlockFetch_Input._Position position new
  HeaderBlockFetch_Input._Position()
• // Set up the input parameters for the call.
• control.Position "Y" // This is a FLD type
  SYS/Character
• position.ORDERNUMBER 1 // This is a FLD type
  SYS/Numeric
• // Create the Input Variable Group DataContract
  class.
• HeaderBlockFetch_Input input new
  HeaderBlockFetch_Input()
• // Assign the Variables to the Input Variable
  Group.
• input.Control control
• input.Position position

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Client Coding

• Call the operation (using try/catch block)
• try
• // Call the operation on the service stub.
• HeaderBlockFetch_Output output
• myOrderClient.GetOrderHeaders(input)
• catch (FaultExceptionltPlexRuntimeExceptiongt ex)
• // Use PlexRuntimeException to report the
  error.
• Console.WriteLine(ex.Detail.Message)

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Client Coding

• Deal with output
• Bind to controls
• // Bind FetchedData output variable to a
  DataGridView DataSource
• dgvOrders.DataSource output.FetchedData
• Process in code
• // Use a .NET iterator to read the FetchedData
  MOV
• foreach (HeaderBlockFetch_Output._FetchedData
  FetchedData in output.FetchedData)
• // Output each name in the FetchedData instance.
• Console.WriteLine(FetchedData.CUSTOMERNAME)

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Client Coding

• Dispose of your client (optional)
• // Call the dispose operation on the service
  stub.
• myOrderClient.Dispose()
• Removes Plex runtime connections for
• Databases
• Remote servers
• Threads
• You should see the following in the VS2008 Output
  window
• Removing Plex .NET Runtime 17654054

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Demos

• Both based on Plex r6.10 Training
• Demo 1
• Basic WCF Service Implementation
• N-Tier Platform Support
• Error Handling
• Demo 2
• A more practical example
• More on coding techniques

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An Introduction to Business Process Modeling

• Time to focus on the Business Process Layer

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An Introduction to BPMWhat and Why?

• BPM represents Processes within an Enterprise
• Generally involve human and automated steps
• Potentially long-running (esp. with Humans in the
  mix!)
• Could involve multiple applications
• Benefits
• Diagramming makes them easy to understand
• Theyre adaptable
• Better able to deal with long running Processes
• A Workflow is one way of modeling a BPM Process

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An Introduction to BPMWhy Workflows?

• Workflows can be Long-running and Stateful
• Provide transparency into a Business Process
• Can increase productivity because they match the
  process being modeled
• Can adapt to changing business needs without
  recoding

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An Introduction to BPMDefinition of a Workflow

• A set of Activities organized into a Business
  Process that organize people and software
• An Activity is a unit of execution within the
  workflow
• Encapsulated functionality
• Designed for reuse
• Calling a Service Operation is one example
• Can be user defined
• Two primary types of Workflow
• Sequential
• State-Machine

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An Introduction to BPMWindows Workflow Foundation

• Microsofts Workflow solution
• Part of .NET Framework 3.0
• Will underpin all of Microsofts future offerings
  that involve workflows
• Consists of
• A Base Activity Library
• A Runtime Engine
• Runtime Services
• Visual Design Tools

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Demo

• Based on Plex r6.10 Training (Lab 3)

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Best Practices Plex Application Development

• Dont add too many service operations
• 4-5 per service is normal
• Create composite units of functionality
• Reduces service complexity
• Avoids chatty interfaces
• Simplify input/output parameter interfaces
• These relate to the input, dual and output
  parameters in your function
• Use human-readable field implementation names
• Dont imbed server functionality in your clients!
• Avoid the need to send configuration data from
  your client applications that use your services.

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Best Practices Troubleshooting

• Always start with a running Plex client-server
  application!
• Adding Package triples to your application is A
  Good Thing.
• Use your Plex runtime .NET log files when WCF
  Services dont work.
• Review your AssemblyList and UDLFileName
  properties
• 9 times out of 10 thats where the problem lies.

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Summary

• Service Connectors are an Abstract representation
  of a service
• Use them to formally define interfaces between
  Plex and other applications
• WCF is only the first implementation
• others will follow!
• WCF Supports C, Java, RPG400 and RPGIV Plex
  Functions
• Services are the most convenient way for BPM
  tools to integrate applications into Business
  Processes

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QA

• Questions?