6.2 Creating an Oracle Enterprise Service Bus Flow

You can create an Oracle Enterprise Service Bus flow using the tools in Oracle JDeveloper ESB Designer. Oracle JDeveloper ESB Designer tools provide a visual approach that simplifies application development and greatly reduce coding tasks.

The basic steps to create the Oracle Enterprise Service Bus flow are:

Create the Oracle JDeveloper ESB Designer applications and ESB projects. See Section 6.3, "Creating Oracle Enterprise Service Bus Projects".
Create ESB systems and, optionally, service groups. See Section 6.4, "Creating Oracle Enterprise Service Bus Systems or Service Groups".
Create the inbound and outbound services, or invoke external services. See Section 6.7, "Adding SOAP Services to Oracle Enterprise Service Bus" and Section 6.8, "Adding Adapter Services to Oracle Enterprise Service Bus".
Create routing services and configure the routing rules. See Section 6.9, "Adding Routing Services to Oracle Enterprise Service Bus" and Section 6.10, "Specifying Routing Rules".
Register services in the ESB projects with the ESB Server. See Section 6.12, "Registering ESB Projects and Services with the ESB Server".

To begin creating an Oracle Enterprise Service Bus flow, you must create an application and then an ESB project. An application contains one or more projects. An ESB project is a collection of related files, for example, all the Oracle Enterprise Service Bus systems, services, and associated files within a single Oracle Enterprise Service Bus flow.

ESB systems and service groups are units for organizing the services for the Oracle Enterprise Service Bus flow.

You create an Oracle Enterprise Service Bus flow by dragging and dropping services from the Oracle JDeveloper Components Palette to the Design tab. These services include adapter, SOAP, and routing services.

The message instance flow can be specified as asynchronous or synchronous execution. Synchronous provides an immediate response to a request; asynchronous does not. For more information, see Section 6.10.4, "How to Specify Synchronous or Asynchronous Execution".

Figure 6-1 is an example of a Design tab of an ESB system in Oracle JDeveloper ESB Designer, showing the service icons in the system.

Figure 6-1 Oracle JDeveloper ESB Designer

Description of "Figure 6-1 Oracle JDeveloper ESB Designer"

For additional information about developing an Oracle Enterprise Service Bus flow with Oracle JDeveloper ESB Designer, see "Developing the Enterprise Service Bus" in Oracle Enterprise Service Bus Developer's Guide.

6.2.1 What Happens When you Create an Oracle Enterprise Service Bus Flow

When the ESB project is registered with the ESB metadata server, ESB artifacts created in Oracle JDeveloper ESB Designer are registered in the design time metadata server.

The ESB service definition files are translated and captured in a relational form in the ORAESB schema in the database repository while the XSD, XSL, and WSDL files are written to the file system. The service definitions in the database repository have pointers to the XSD, XSL, and WSDL files on the file system.

At startup, an ESB runtime server automatically accesses the design metadata server to cache the complete information for the ESB runtime services. During runtime the server automatically listens on the control topic in the metadata server for updates to the information, and refreshes the cache from the database repository if changes are found.

At runtime, the ESB message flow is initiated by an inbound adapter polling or listening for an event, such as a file copied to the directory specified for an inbound file adapter. The ESB flow is also initiated when an external SOAP/HTTP client/process invokes the Web service associated with an ESB service.

ESB enables you to modify some metadata at design time with Oracle ESB Control. These updates are automatically sent to the design time metadata server.

Figure 6-2 is an example of Oracle Enterprise Service Bus architecture in a single instance environment.

Figure 6-2 Oracle Enterprise Service Bus Architecture - Single Instance Environment

Description of "Figure 6-2 Oracle Enterprise Service Bus Architecture - Single Instance Environment"

6.2.2 What You May Need to Know

When you create an ESB project and services in Oracle JDeveloper ESB Designer, files are generated for the ESB flow. Table 6-1 lists the types of ESB files generated, a brief description of the file, and whether the file is used at design time or runtime.

Table 6-1 ESB Files

Type of File	Description	Design Time	Runtime
Project (esb)	Project file created whenever an ESB project is created in Oracle JDeveloper ESB Designer	yes	no
System (esbsys)	System file created whenever an ESB system is created in Oracle JDeveloper ESB Designer	yes	no
Service group (esbgrp)	Service group file created whenever an ESB system is created in Oracle JDeveloper ESB Designer	yes	no
Service (esbsvc)	Service definition file created whenever an adapter, routing, or SOAP service is created in Oracle JDeveloper ESB Designer	yes	no
Service (wsdl)	Service WSDL file	yes	yes
Adapter header (wsdl)	Inbound and outbound adapter header files created whenever an adapter service is created in Oracle JDeveloper ESB Designer	yes	yes
Toplink_mappings (xml)	Mapping file for DB adapter	yes	yes
Schema (xsd)	Schema table file created when a DB adapter is created in Oracle JDeveloper ESB Designer	yes	yes
Data mapping (xsl)	Transformation file created when a data transformation map is generated in Oracle JDeveloper ESB Designer	yes	yes