Persisting Java Objects with InterSystems XEP
XEP is a lightweight API that provides high-performance Java technology for persisting simple to moderately complex object hierarchies. XEP projects the data in Java objects as persistent events (database objects that store a persistent copy of the data fields) in an InterSystems IRIS™ database. XEP is optimized for applications that must acquire and persist data at the highest possible speed.
InterSystems IRIS™ provides Java APIs for easy database access via SQL tables and objects. This book discusses the API for object access. See Using Java JDBC with InterSystems IRIS
for SQL table access.
This section specifies requirements and provides instructions for installing InterSystems IRIS and configuring your environment to use XEP.
A 64–bit Java JDK supported by this release of InterSystems IRIS (see “Supported Java Technologies” in the online InterSystems Supported Platforms
document for this release).
Computers that run your Java client applications do not require InterSystems IRIS, but they must have a connection to the InterSystems IRIS Server and must be running a supported version of the Java JDK.
When installing InterSystems IRIS, select the Development environment:
If InterSystems IRIS has been installed with security level 2, open the Management Portal and go to System Administration > Security > Services, select %Service_CallIn, and make sure the Service Enabled box is checked.
If you installed InterSystems IRIS with security level 1 (minimal) it should already be checked.
All XEP applications require JAR files intersystems-jdbc-3.0.0.jar
(see “The InterSystems IRIS Java Class Packages
” in Using Java JDBC with InterSystems IRIS
for file location and other details). Your CLASSPATH
environment variable must include the full paths to these files. Alternately, they can be specified in the Java command line classpath
In order to run XEP applications, the following requirements must be met on all platforms:
The InterSystems IRIS User namespace must exist and must be writable.
Your Path must include dynamic library load path <install-dir>/bin:
In Windows, add it to your PATH environment variable.
In UNIX® and related operating systems, add it to your LD_LIBRARY_PATH environment variable.
In Mac OS X, add it to your DYLD_LIBRARY_PATH environment variable.
If your Path variable includes more than one <install-dir>/bin path (for example, if you have installed more than one instance of InterSystems IRIS) only the first one will be used, and any others will be ignored.
The default stack size of the Java Virtual Machine on Windows is too small for running XEP applications (running them with the default stack size causes Java to report EXCEPTION_STACK_OVERFLOW). To optimize performance, heap size should also be increased. To temporarily modify the stack size and heap size when running an XEP application, add the following command line arguments:
Content Date/Time: 2019-10-14 06:33:38