Information Technology Reference
In-Depth Information
1. Introduction ........................................ 86
1.1.ProgrammingModelsforBusinessApplications ................. 86
1.2.BusinessApplicationsonDisconnectedDevices ................. 87
1.3.ProgrammingModelsforDisconnectedBusinessApplications ......... 88
1.4.RelatedWork .................................... 89
1.5.ChapterStructure .................................. 91
1.6.MotivatingApplication............................... 91
2.Life-CycleofaDisconnectedBusinessApplication .................. 93
3.SynchronizationTechniques............................... 96
3.1.DataReplication................................... 96
3.2.MethodReplay ................................... 98
4. Disconnected Programming Models: Service Data Objects and Enterprise JavaBeans 100
4.1.ServiceDataObjects:Concepts .......................... 101
4.2.EnterpriseJavaBeans:Concepts .......................... 105
4.3.ComparisonofSDOandEJBApplicationProgrammingModels ........ 108
4.4. Suitability of SDOs & EJBs for Disconnected Applications ........... 110
4.5.
EJBSync
:MiddlewareforDisconnectedEJBs .................. 113
5.EvaluatingDisconnectedProgrammingModels .................... 118
5.1.ExoticTransactionModels............................. 118
5.2.Message-BasedProgrammingModel ....................... 119
5.3.DataReplicationversusMethodReplay...................... 121
5.4.UsefulDisconnectableBusinessApplications................... 125
6.SummaryandConclusion ................................ 127
Acknowledgements.................................... 128
References......................................... 128
1.
Introduction
1 . 1
P r o g r a m m i n g M o d e l s f o r B u s i n e s s A p p l i c a t i o n s
A
business application
is characterized by the fact that the application (1) updates
state that is shared by multiple users; (2) must perform these updates transactionally
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to a shared database; and (3) must operate securely. Business applications there-
fore have requirements that other applications do not: chiefly, to access persistent
shared datastores securely and transactionally. Programming models can ease the
difficulty of developing complex business logic that meets these requirements. This
is typically done by abstracting business application requirements as generic services
or middleware that the developer can access in as unobtrusive a manner as possible.
Good programming models enable a “separation of concerns” through which the
application developer can concentrate on the application-specific logic, and assume
