Building Extensible Composite Applications with SAP

Matthias Steiner is a Solution Architect for SAP Custom Development. Using the potential of SOA and composite applications, his role is to evaluate SAP's cutting-edge technologies and transform them into real solutions for SAP customers. He began his career with SAP in 2002 and has gathered significant experience in numerous enterprise-scaled development projects in both the ABAP and the Java world. He actively contributes to the SAP Community Network (SDN): https: //www.sdn.sap.com/irj/scn/weblogs?blog=/pub/u/5263.

* ... Introduction ... 9 * 1 ... Design Principles of Modern Java Applications ... 17 * 1.1 ... Application Architecture and Design ... 17 * 1.1.1 ... Application Layering ... 19 * 1.1.2 ... Data Layer (Backend Systems and Data Sources) ... 20 * 1.1.3 ... Connectivity Layer ... 21 * 1.1.4 ... Business Logic Layer ... 22 * 1.1.5 ... Presentation Layer ... 24 * 1.1.6 ... Process Layer ... 25 * 1.2 ... Summary ... 27 * 2 ... Fundamentals of Extensibility Concepts ... 29 * 2.1 ... Basic Concept ... 29 * 2.1.1 ... Field Extensibility and Process Extensibility ... 30 * 2.1.2 ... Explicit versus Implicit Extensibility ... 31 * 2.1.3 ... Basic Concept of Procedural Extensibility Techniques ... 34 * 2.2 ... Extensibility Implications and Non-Functional Prerequisites ... 35 * 2.2.1 ... Security ... 36 * 2.2.2 ... Performance ... 37 * 2.2.3 ... Data Integrity ... 39 * 2.2.4 ... Supportability ... 40 * 2.2.5 ... Flexibility ... 41 * 2.2.6 ... Configuration ... 42 * 2.2.7 ... Documentation ... 42 * 2.3 ... Application Componentization ... 43 * 2.4 ... Typical Use-Cases ... 44 * 2.4.1 ... Business Add-Ins (BAdIs) ... 44 * 2.4.2 ... Backend Abstraction Layer (BAL) ... 44 * 2.5 ... Exemplary Business Scenario ... 46 * 3 ... Extensibility Based on Java Class Loading ... 47 * 3.1 ... Use-Case Introduction ... 47 * 3.2 ... Creating the Example Application ... 49 * 3.2.1 ... Creating the Development Configuration ... 49 * 3.2.2 ... Creating the Development Components ... 52 * 3.2.3 ... Creating the Public Parts ... 55 * 3.2.4 ... Importing the Software Component Archive ... 58 * 3.2.5 ... Code Walkthrough ... 62 * 3.2.6 ... Specifying Dependencies Between Development Components ... 66 * 3.2.7 ... Testing the Application via the Web Services Navigator ... 70 * 3.3 ... Creating the Custom Implementation ... 72 * 3.3.1 ... Importing the Custom Implementation ... 72 * 3.3.2 ... Reviewing the Custom Implementation ... 77 * 3.3.3 ... Testing the Customer Implementation ... 78 * 4 ... Extensibility Based on Enterprise JavaBeans ... 81 * 4.1 ... Use-Case Introduction ... 81 * 4.2 ... Creating the Example Composite Application ... 82 * 4.2.1 ... Creating the Composite Application ... 82 * 4.2.2 ... Creating the Business Partner BO ... 85 * 4.2.3 ... Modeling the Business Object Attributes ... 86 * 4.2.4 ... Creating the Application Service ... 91 * 4.2.5 ... Exposing the Application Service as Web Service ... 95 * 4.2.6 ... Code Walkthrough ... 97 * 4.2.7 ... Running the Composite Application ... 100 * 4.3 ... Developing the Extension Points ... 102 * 4.3.1 ... Developing the Extension Point Interface and Standard Implementation ... 103 * 4.3.2 ... Integrating the Extension Points into the Process Flow ... 105 * 4.3.3 ... Exposing the Extension Points ... 106 * 4.4 ... Developing a Custom Implementation ... 109 * 4.4.1 ... Enterprise Application ... 111 * 4.4.2 ... Extension Points (EJB Module) ... 111 * 4.4.3 ... Mail Template (Web Module) ... 112 * 4.4.4 ... Defining DC Dependencies ... 112 * 4.4.5 ... Configuration ... 113 * 4.5 ... Summary ... 114 * 5 ... Extensibility Based on Web Services ... 115 * 5.1 ... Use-Case Introduction ... 116 * 5.2 ... Creating the Example Application ... 116 * 5.3 ... Introduction to Enterprise Services ... 118 * 5.4 ... Creating the Service Provider ... 122 * 5.4.1 ... Creating the Stateless Session Bean ... 122 * 5.4.2 ... Exposing the Session Bean as a Web Service ... 126 * 5.5 ... Creating the Service Consumer ... 130 * 5.5.1 ... Backend Abstraction in Action ... 130 * 5.5.2 ... Creating the Web Service Client ... 130 * 5.5.3 ... Creating the Consumer EJB Session Bean ... 135 * 5.6 ... Creating an Alternative Web Service Provider ... 138 * 5.7 ... Summary ... 141 * 6 ... Introducing an Extensibility Framework ... 143 * 6.1 ... Architecture and Capabilities ... 144 * 6.1.1 ... Support for Explicit and Implicit Extensions ... 146 * 6.1.2 ... ExtensionSpot Annotation ... 147 * 6.1.3 ... ExtensionPoint Interface ... 149 * 6.1.4 ... ExtensionPointInterceptor ... 150 * 6.1.5 ... ExtensibilityFactory ... 153 * 6.1.6 ... Prerequisites of the Extensibility Framework ... 155 * 6.1.7 ... Summary ... 156 * 6.2 ... Implementing the Extensibility Framework ... 157 * 6.3 ... Testing and Debugging the Extended Application ... 162 * 6.4 ... Summary ... 163 * 7 ... Summary ... 165 * 7.1 ... Extensibility Based on Java Class Loading ... 166 * 7.2 ... Extensibility Based on EJBs ... 167 * 7.3 ... Extensibility Based on Web Services ... 168 * 7.4 ... Implicit Extensibility Based on Interceptors ... 169 * 7.5 ... Comparison ... 170 * ... Appendices ... 175 * A ... Further Reading ... 175 * B ... The Author ... 177 * ... Index ... 179