The Component Dilemma Handicaps of Component Architectures in Commercial Information Systems Michael Löwe IDPT 2002

The Component Dilemma2 Contents Theoretical promises Practical handicaps to keep them Perspectives and Solutions Perfect Pragmatic

The Component Dilemma3 The Theoretical Promises Well-Structured Maintainable Applications Divide and Conquer Reusable Software Component Market Places Efficient Software Process

The Component Dilemma4 Maintainable Applications Marketing Customer/Partner ContractsClaims Provision Reassurance Consortia Finance Product/Process Sample Insurance Architecture Well-isolated Application Components Thin Interfaces Independent Development Application Level Component Models

The Component Dilemma5 Application Components Product Contract Model View Class Object Tariff PoliceBillingLiability Interests MarketingStatisticProcess Consortia Coverage Re.-Ass. Competence

The Component Dilemma6 Application Components Application Legacy Structure Application New Application Application New Component Application Interface Application Interface Application Interface Application Interface Migrating Component by Component Migrating Application by Application

The Component Dilemma7 Handicaps Branch-specific application domain architectures and components are not available, yet. Methods for migrating legacy systems into component structures are not sufficient. Integration of application level components is not easy and cost-intensive.

The Component Dilemma8 Divide and Conquer Global Requirements Requirements for Component 1 Requirements for Component 2 Requirements for Component n Analysis Interfaces 1 Interfaces 2 Interfaces... Interfaces n Construction plan Interfaces...

The Component Dilemma9 Divide and Conquer Requirements for Component n Team 2 Requirements for Component 1 Requirements for Component 2 Team 1 Realization Correct Component n Correct Component n Correct Component 1 Correct Component 1 Correct Component 2 Correct Component 2

The Component Dilemma10 Divide and Conquer Synthesis Interfaces 1 Interfaces 2 Interfaces... Interfaces n Interfaces... Correct Component 1 Correct Component 1 Correct Component 2 Correct Component 2 Correct Component n Correct Component n Correct System Correct System Component Architecture

The Component Dilemma11 Handicaps Analysis results cannot be proven correct. Component architectures do not like change. Methods for the evolution of component structures are not sufficient.

The Component Dilemma12 System 1System 3System 2 Infrastructure Object Model, Communication, Messaging, Transactions, Synchronization, Security, Safety, Authorization, Workflow, Dialogs, Persistence, Logging, Administration, Operating,..... Reusable Software Library Component Component

The Component Dilemma13 Reusable Software Dependent Classes Dependent Classes Class A Class B myA myB Decoupled by Observer Pattern Decoupled by Observer Pattern Subject Class A Observer Class B observers myA Not reusable class AProbably reusable class A

The Component Dilemma14 Handicaps Components need more infrastructure than function call. Function calls need some infrastructure themselves. There are several competing and incompatible component infrastructures. Methods and tools for migrating components into another infrastructure are not sufficient. Simply reusable components are not simple.

The Component Dilemma15 Suppliers Application (Client) Application (Client) Component Market Places Database System(s) Workflow Management System Office Components Transaction Monitor Internet Components Commercial Dependency GroupWare MiddleWare Operating System(s)

The Component Dilemma16 Handicaps Using components from a component market increases commercial dependencies. Consequent application of standard components leads to standard business.

The Component Dilemma17 Efficient Software Process Webshere Multi-Tier Framew orks EDI DCE 3-Tier Messaging Internet Intranet Extranet Active X Web-Server Internet-Browser XML Application Server Fat Clients Java Beans DCOM Thin Clients UML JDBC DAO Applets ODBC OLE DHTML HTML XSLT DTD XML-Schema ASP JSP COM+.Net C# RMI PGP SSL IIOP CORBA EJB Servlets Ultra Thin Clients

The Component Dilemma18 Efficient Software Process Machine or Byte-Code Language Standard Service Component Model Platform Services Inter Platform Services JVM Java Java-Classes Beans Enterprise Beans Corba-ORB Application Domain ServicesBranch Model Efficience, Security,... Algorithms, Patterns, Program Reuse,... GUI, Collections, Threads, DBM,... Object Reuse Technical Information Systems Infrastructure Application and Systems Integration Application Domain System Infrastructure

The Component Dilemma19 Handicaps There are not enough software engineers who are used ”to think in components”. Return on investments into component architectures cannot be expected within a short time.

The Component Dilemma20 Solutions (perfect) Technical Components Application Components Evolution Migration Componentization of Infrastructures Standardization of Interaction Inter-Infrastructure Techn. Components General Components Branch Components Branch Architectures General Architectures Prototype Frameworks Legacy Reengineering Infrastructure Migration Framework Migration

The Component Dilemma21 Solutions (pragmatic) Do not build for eternity! (20 years is eternity!) Design for today not for the future! Restrict maintenance! Bugs and errors Legal changes Rebuild often (5 - 8 years, complete systems)! Change platforms and tools if needed or wanted! Educate your people!

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