Patterns: Implementing Self-Service in an SOA Environment

Chapter 7. Application and system design guidelines 187

7.4 Design guidelines for J2EE Connector Architecture

The J2EE Connector Architecture (JCA) defines a set of standards about how a

resource adapter provides connectivity to an enterprise system application (EIS)

and how the system contracts with an application server.

There are set of contracts between the resource adapter and the application

server which provides services to the resource adapter and maintains a

pluggable mechanism when running in the application server.

There are currently two versions of the JCA specification. The JCA 1.0

specification includes outbound communication and JCA 1.5 includes outbound

as well as inbound communication.

You can find these specifications here:

http://java.sun.com/j2ee/connector/

7.4.1 Components of J2EE Connector Architecture

Figure 7-20 J2EE Connector Architecture components

System Level Contracts

Life Cycle Management

Connection Management

Transaction Management

W ork Management

Message Inflow

Transaction Inflow

Security Management

E IS -S pecific

Interface

Common

Client

Interface

Application

Component

J2EE

Application Server

Resource

Adapter

Enterprise

Information System

188 Patterns: Implementing Self-Service in an SOA Environment

As shown in Figure 7-20 on page 187, Version 1.5 of the J2EE Connector

Architecture defines a number of components and interfaces that make up this

architecture to connect to any EIS. JCA main components include resource

adapter, system level contracts between application server and resource

adapter, and the Common Client Interface (CCI).

JCA 1.5 defines the following:

򐂰 Common Client Interface (CCI)

The CCI defines a common API for interacting with resource adapters. It is

independent of a specific EIS. A Java developer communicates to the

resource adapter using this API.

򐂰 System contracts

These contracts are a set of system-level contracts between an application

server and EIS. These extend the application server to provide:

–

Connection management enables an application server to pool

connections to the underlying EIS and enables application components to

connect to an EIS. This leads to a scalable application environment that

can support a large number of clients requiring access to an EIS.

–

Transaction management enables an application server to use a

transaction manager to manage transactions across multiple resource

managers. This contract also supports transactions that are managed

internal to an EIS resource manager without the necessity of involving an

external transaction manager.

–

Security management provides support for a secure application

environment that reduces security threats to the EIS and protects valuable

information resources managed by the EIS

–

Life cycle management (new in JCA 1.5) enables an application server to

manage the life cycle of a resource adapter. This contract provides a

mechanism for the application server to bootstrap a resource adapter

instance during its deployment or application server startup, and to notify

the resource adapter instance during its undeployment or during an

orderly shutdown of the application server.

–

Work management (new in JCA 1.5) enables a resource adapter to do

work (monitor network endpoints, call application components, and so on)

by submitting Work instances to an application server for execution. The

application server dispatches threads to execute submitted Work

instances. This allows a resource adapter to avoid creating or managing

threads directly, and allows an application server to efficiently pool threads

and have more control over its runtime environment. The resource adapter

can control the security context and transaction context with which Work

instances are executed.