ARCH-07: Implementing the OpenEdge™ Reference Architecture – Part 2 John Sadd Progress Fellow and OpenEdge Evangelist

Modern Application Architecture OpenEdge Reference Architecture – a layered view Separated presentation and integration layers Users Enterprise Services Presentation Layer Integration Layer Common business logic with advanced models Business Servicing Layer Data access abstracted from storage Data Access Layer Managed Data Stores Unmanaged Data Stores

Agenda Introducing the Service Interface Layer Managing ProDataSet Instances Context Management Creating a WebSpeed® User Interface Additional Topics and Futures Conclusions

SOA – Service Interaction Model Bind Invoke Service Requestor Provider Broker/ Directory Find / Details Publish Enterprise Services Bus Task

Container-managed Support Services Security Transaction Control Session/Context Management Client Side Fn() Presentation Container Service Proxy Service Interface Service Container Order Mgmt Server Side …

The Service Interface Layer in the Architecture Users Enterprise Services Presentation Layer Integration Layer Service Interface Business Servicing Layer Data Access Layer Managed Data Stores Unmanaged Data Stores

Role of the Sample Service Interface Layer Manages server-side entities Keeps an in-memory catalog of running instances Provides standard one-call access to server-side procedures Provides a single simplified API from client to server

The Service Interface Layer Client Server UI Procedure Business Entity Data-Access Object DATASET dsOrder DATASET dsOrder DATASET dsOrder RUN fetchOrder IN hdsOrder (. . . , OUTPUT DATASET dsOrder BY-REFERENCE) RUN FetchWhere IN hEntity (. . ., OUTPUT DATASET phFetchDataSet BY-REFERENCE) fetchWhere: FILL ATTACH Client Proxy Server Gateway Service Interface

(call to server-side gateway) Client-side SI Proxy Client proxy procedure User interface procedure proSIproxy.p PROC fetchWhere: RUN proSIgateway.p ON hAppServer (INPUT “Order”, INPUT “fetchWhere”…) … dsOrderWinAdv.w {dsOrder.i} {proSIproxyStart.i} … RUN fetchWhere IN ghProxySIproc (INPUT “Order”, INPUT ttContextDSOrder, OUTPUT DataSet dsOrder). (call to server-side gateway)

Server-side SI Procedures (call from client session) Server service procedure Server gateway procedure proSIserver.p DEFINE T-T ttEntity… FN startEntity: FN getEntityHandle: /* entity temp-table lookup */ FN getDAOHandle: proSIgateway.p hEntity = getEntityHandle in hSI. RUN fetchWhere in hEntity … (call to Business Entity API)

Gateway Procedure API Five standard parameters Logical entity name Logical operation name Context/parameter temp-table for passing any related values back and forth OUTPUT or INPUT-OUTPUT ProDataSet Depending on whether ProDataSet definition or values need to be passed in OUTPUT status for exception handling Useful default for many operations Use custom APIs and custom gateway procedures for special operations

Agenda Introducing the Service Interface Layer Managing ProDataSet Instances Context Management Creating a WebSpeed® User Interface Additional Topics and Futures Conclusions

Management of ProDataSet Instances Which object “owns” the ProDataSet instance on server and client? ProDataSets can be passed BY-REFERENCE to avoid copying The caller’s instance is always used, even on OUTPUT This will be extended in 10.1 to support a “pull” model where the called procedure’s instance is used

ProDataSet Instances on OUTPUT Client Server UI Procedure Business Entity Data-Access Object DATASET- HANDLE DATASET dsOrder DATASET dsOrder DATASET dsOrder BY-REF HANDLE BY-REF RUN fetchOrder IN hdsOrder (. . . , OUTPUT DATASET dsOrder BY-REFERENCE) RUN FetchWhere IN hEntity (. . ., OUTPUT DATASET phFetchDataSet BY-REFERENCE) fetchWhere: FILL ATTACH Client Proxy Procedure Server Gateway Procedure

Agenda Introducing the Service Interface Layer Managing ProDataSet instances Context Management Creating a WebSpeed® User Interface Additional Topics and Futures Conclusions

Context Management Basics Target environment is client to state-less or state-free AppServer Each interaction is independent Maintain context between related interactions

Passing Context between Client and Server Context/Parameter temp-table passes context back and forth Name & Value fields allow flexibility Context is maintained on the client Useful for small amounts of data Also for context used on the client And for context modified on the client

Context Between Client and Server Business Entity UI Procedure DATASET dsOrder DATASET dsOrder context/parameter temp-table RUN FetchWhere IN hEntity (. . ., OUTPUT DATASET phFetchDataSet BY-REFERENCE) RUN fetchOrder IN hdsOrder (. . . , OUTPUT DATASET dsOrder BY-REFERENCE) Server Gateway Procedure Client Proxy Procedure WhereString = “…” NextRowid = 63524

Context Maintained on the Server Hold context in a shared server-side data store Typically a database table Useful for context not to pass back and forth Session context such as language, authorization that does not change Requires a Context ID passed from the client GUID support in sample and in 10.1

Context Stored on the Server Client Business Entity UI Procedure DATASET dsOrder DATASET dsOrder context/parameter temp-table RUN FetchWhere IN hEntity (. . ., OUTPUT DATASET phFetchDataSet BY-REFERENCE) RUN fetchOrder IN hdsOrder (. . . , OUTPUT DATASET dsOrder BY-REFERENCE) Server Gateway Procedure Client Proxy Procedure ContextID = 95847 95847 English Auth …

ProDataSet and Temp-table Context Store retrieved data in a context table For WebSpeed or other clients with no ProDataSet support RAW fields and BLOBS for generic storage Store successive updates before commit Allows partial validation on the server Final update ProDataSet rebuilt from context

ProDataSet or Temp-table Data as Context Server Client Business Entity UI Procedure DATASET dsOrder DATASET dsOrder ContextID = 95847 RUN FetchWhere IN hEntity (. . ., OUTPUT DATASET phFetchDataSet BY-REFERENCE) RUN fetchOrder IN hdsOrder (. . . , OUTPUT DATASET dsOrder BY-REFERENCE) “OrderNum = 1” Server Gateway Procedure Client Proxy Procedure 95847 Order 1 Line 1 95847 Order 1 Line 1 95847 Order 1 Line 2

Agenda Introducing the Service Interface Layer Managing ProDataSet Instances Context Management Creating a WebSpeed® User Interface Additional Topics and Futures Conclusions

Agenda Introducing the Service Interface Layer Managing ProDataSet Instances Context Management Creating a WebSpeed® User Interface Additional Topics and Futures Conclusions

White Paper: Using an Unmanaged Data Store Uses an XML document in place of the database Alternative Data-Source procedure identifies the document Custom code populates the ProDataSet Remaining Business Entity code runs unmodified

White Paper: Simple .NET Interface to Business Entities Code generator creates a XSD file with a DataSet description This in turn creates a C# class file for the DataSet C# version of the client proxy runs the same gateway procedure on the AppServer C# DataSet class file used to build the UI

White Paper: Advanced Business Logic The role of database trigger procedures One Business Entity accessing another One Data Access Object accessing another When to allow direct database access

The Sample Implementation and Future Releases Significant new language extensions planned for 10.1 and beyond Elements of an OO4GL such as classes Auditing and other built-in core services Materials to be revised and extended to describe 10.1 best practices

Agenda Introducing the Service Interface Layer Managing ProDataSet Instances Context Management Creating a WebSpeed User Interface Additional Topics and Futures Conclusions

In Summary Think about and plan for services in your application Think about which objects control the data Think about context and other aspects of a stateless application server

Questions?

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