System contracts
In this section we learn about the basic components of the JCA architecture. JCA defines a standard set of system-level contracts between the Java EE application server and a resource adapter. The application server and the resource adapter connect and interact with each other using the system contracts.
Seven types of system contracts are defined in the JCA specification:
| Connection management contract: Allows the application server to create a physical connection to the EIS. It also provides a mechanism for the application sever to manage connection pooling. |
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| Transaction management contract: Provides transactional support allowing the EIS to participate in a transaction. Transactions can be managed by the application server's transaction manager with multiple EISs and other resources as participants. |
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| Security contract: Allows application components in an application server to access the EIS securely. The security contract is an extension of the connection management contract implemented by adding Java Authentication and Authorization Service (JAAS) into connection management interfaces. |
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| Life cycle management contract: Allows the application server to manage the life cycle of the resource adapter. It provides a mechanism for the application server to start and shut down an instance of the resource adapter. |
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| Work management contract: Allows the resource adapter to submit work to the application server for execution. The application server dispatches a thread to handle the work. This contract is optional. |
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| Transaction inflow contract: Allows the EIS to propagate a transaction through the resource adapter to the application server. |
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| Message inflow contract: Allows the resource adapter to pass synchronous or asynchronous inbound messages to message endpoints on the application server. |
Figure | 0-2 shows the integration between EIS, application server, and application component. These components are bound together using JCA contracts.
Figure 20-2 System contract, application server, resource adapter integration
To find out more about JCA Specification, visit the JCA specification Web site at:
http://java.sun.com/j2ee/connector/download.html
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