Introduction to EIS Projects (ELUG)
For the latest EclipseLink documentation, please see http://www.eclipse.org/eclipselink/documentation/
This section provides an overview of EIS projects and their components.
For information on project concepts and features common to more than one type of EclipseLink projects, see Introduction to Projects.
EIS Project Concepts
Use an EIS project for transactional persistence of Java objects to a nonrelational data source accessed using a Java EE Connector Architecture (JCA) adapter and EIS records.
JCA provides a Common Client Interface (CCI) API to access nonrelational EIS. This provides a similar interface to nonrelational data sources as JDBC provides for relational data sources. This API defines several types of nonrelational record types including mapped and indexed. XML has emerged as the standard format to exchange data, and most leading JCA adapter providers have extended the CCI API to define XML data records.
To use a JCA adapter with EclipseLink EIS, the JCA adapter must support the JCA CCI interface. At run time, your JCA adapter and the Java connector.jar file (that contains the javax.resource.cci and javax.resource.spi interfaces that EclipseLink EIS uses) must be on your application or application server classpath.
If you are using Workbench, you must add your JCA adapter to the Workbench classpath. By default, Workbench updates its classpath to include the Java 1.5.n connector.jar file from <ECLIPSELINK_HOME>/utils/workbench/jlib. If this version of the connector.jar file is incompatible with your environment, edit the workbench.cmd or workbench.sh file in <ECLIPSELINK_HOME>/utils/workbench/bin to change the path to this file. For more information, see Configuring the Workbench Environment.
EIS includes legacy data sources, enterprise applications, legacy applications, and other information systems. These systems include such sources as Custormer Information Control System (CICS), Virtual Storage Access Method (VSAM), Information Management System (IMS), ADABASE database, and flat files.
We recommend using EIS projects to integrate EclipseLink with a legacy or nonrelational data source. Other methods of accessing EIS data sources include:
- Using a specialized JDBC driver that allows connecting to an EIS system as if it were a relational database. You could use an EclipseLink relational project with these drivers.
- Linking to or integrating with the EIS data from a relational database, such as Oracle Database.
- Using a proprietary API to access the EIS system. In this case it may be possible to wrap the API with a JCA CCI interface to allow usage with an EclipseLink EIS project.
EclipseLink provides support for mapping Java objects to EIS mapped, indexed, and XML records, through JCA, using the EclipseLink EIS mappings.
You configure an EclipseLink EIS descriptor to use a particular EIS record format. EclipseLink EIS mappings use their EIS descriptor's record format configuration to determine how to map their Java objects to EIS records.
If you use XML records, the EclipseLink runtime performs XML data conversion based on one or more XML schemas. In an EIS project that uses XML records, Workbench directly references schemas in the deployment XML, and exports mappings configured with respect to the schemas you specify. For information on how to use Workbench with XML schemas, see Using XML Schemas. For information on how EclipseLink supports XML namespaces, see XML Namespaces Overview.
This table describes the components of an EIS project.
EIS Project Components
You can create an EIS project with Workbench for use with EIS XML records or you can build an EIS project in Java for use with any supported EIS record type.
In an EIS project, your EIS interactions can make full use of EclipseLink queries . However, you cannot use EclipseLink expressions with EIS: in an EIS project, interactions replace expressions.