New and Changed Features in Oracle CEP 3.0

You can now configure multiple servers in an Oracle CEP domain, and cluster them together to achieve high availability.

Caching

Oracle CEP applications can optionally publish or consume events to and from a cache to increase the availability of the events and increase the performance of their applications. A cache is a temporary storage area for events, created exclusively to improve the overall performance of your application; it is not necessary for the application to function correctly.

Record and Playback of Events

The event repository feature of Oracle CEP allows you to record events flowing through an event processing network (EPN) and store them so you can later play back the events. The event repository is configured per stage, such as a processor or stream.

Visualizer Administration Console

Oracle CEP Visualizer, henceforth called Visualizer for simplicity, is a Web 2.0 application that consumes data from Oracle CEP, displays it in a useful and intuitive way to system administrators and operators, and, for specificied tasks, accepts data that is then passed back to Oracle CEP so as to change it configuration.

HTTP Publish-Subscribe Adapter

An HTTP Publish-Subscribe Server is a mechanism whereby Web clients, such as browser-based clients, subscribe to channels, receive messages as they become available, and publish messages to these channels, all using asynchronous messages over HTTP. Every instance of Oracle CEP includes a pub-sub server that programmers can use to implement HTTP publish-subscribe functionality in their applications.

JMS Adapter

Oracle CEP provides both inbound and outbound JMS adapters that you can use in your event applications to send and receive messages to and from a JMS queue, respectively, without writing any Java code.

Configuration Wizard for Creating Domains

Event Processing Language (EPL) New Features

Parameterized Queries—Parameterized queries allow you to put placeholders inside of an EPL query in the form of a question mark. At runtime you bind these placeholders with values and they are then compiled into regular statements. The process is much like the PreparedStatement in JDBC.

See Parameterized Queries.

Subqueries—EPL supports both simple subqueries as well as correlated subqueries. In a simple subquery, the inner query is not correlated to the outer query. Correlated subqueries allow SELECT clauses to be embedded within another SELECT or WHERE clause. Both IN and EXISTS keywords are available when subqueries are used in the WHERE clause. Previously they were available only in the FROM clause and without the ability to correlate the inner and outer query.

See Simple and Correlated Subqueries.

Dynamic Event Properties—Dynamic (unchecked) properties are event properties that need not be known at statement compilation time. Such properties are resolved during runtime. The idea behind dynamic properties is that for a given underlying event representation, the properties are not always known in advance. An underlying event may have additional properties that are not known at statement compilation time, but these properties might still be required in an EPL query. The concept is especially useful for events that represent rich, object-oriented domain models or when generic container events are used.

In conjunction with dynamic event properties, the following functions have also been added to this release: INSTANCEOF, CAST, and EXISTS.

See Dynamic Event Properties.

Output Window Events—Allows you to output the entire contents of the retain window.

No documentation available for Beta.

Security New Features

Changed and Deprecated Features in Oracle CEP 3.0

Version 3.0 of Oracle CEP includes the following changed and deprecated features:

Simpler Helloworld Example

Programming Model

Domain Directory Structure Changes

So as to support clustering and a multi-server environment, the directory structure of the out-of-the-box and sample domains has changed.

Previously, all domain files were located directly under the domain directory, such as BEA_HOME/wlevs30/samples/domains/helloworld_domain, where BEA_HOME refers to the top-level installation directory of Oracle CEP.

In the 3.0 release, the domain directory contains one or more sub-directories that correspond to a single server; this directory contains all the configuration files for that server. For example, the HelloWorld domain contains a single server whose configuration files are located in the following directory: BEA_HOME/wlevs30/samples/domains/helloworld_domain/defaultserver.

The new Configuration Wizard for creating domains follows this updated directory structure.

New and Deprecated Options in the Deployer Tool

When using the -install command to install an application, Oracle CEP automatically starts it after all internal initialization tasks have completed. Subsequently, if you stop and start the Oracle CEP server instance, the application is automatically stopped and started, respectively.

The Deployer tool has two new options: -suspend and -resume. Users should use -suspend to suspend a currently running application, and -resume for it to resume running.

Changes in Management, Monitoring, and JMX

Changes in Logging

Upgrading a 2.0 Application to run on Version 3.0 of Oracle CEP

This section describes the steps you must take to upgrade an application that you developed in Version 2.0 of Oracle CEP (previously called WebLogic Event Server) so that it runs on Version 3.0.

Update the MANIFEST.MF file to import new versions of Spring framework and Oracle CEP packages, as well as new required packages. In paticular:

Update the version of all imported Spring framework packages to 2.5.5. For example:

Import-Package:
   org.springframework.aop.framework;version="2.5.5",
   org.springframework.aop;version="2.5.5",
   ...

Update the version of any imported Oracle CEP packages to 3.0.0.0. For example:

Import-Package:
   com.bea.wlevs.ede;version="3.0.0.0",
   com.bea.wlevs.ede.api;version="3.0.0.0",
   ...

Add the following packages to the Import-Package header if they are not already included:

Import-Package:
   com.bea.wlevs.management.configuration.spi;version="3.0.0.0",
   com.bea.wlevs.management.spi;version="3.0.0.0",
   com.bea.wlevs.monitor;version="3.0.0.0",
   com.bea.wlevs.spi;version="3.0.0.0",
   com.bea.wlevs.spring.support;version="3.0.0.0",
   commonj.work;version="1.4.0.0",
   org.springframework.osgi.extensions.annotation;version="1.1.0",
   com.bea.wlevs.ede.spi;version="3.0.0.0",
   com.bea.wlevs.configuration.internal;version="3.0.0.0",
   ...

If you use Spring or Spring Dyanmic Modules for OSGI (Spring DM) features in your application, it is possible that the declaration of the features in the Spring application context file has changed. If this is the case, you must update these declarations in the EPN assembly file of your Oracle CEP application.

Note:

This change is a result of the upgrade of the Spring framework (from 2.0 to 2.5) that occurred between WebLogic Event Server 2.0 and Oracle CEP 3.0, not as a direct result of the Oracle CEP upgrade.

Refer to the appropriate 2.5 XSD Schemas for any changes:

Spring: http://www.springframework.org/schema/beans/spring-beans.xsd

Spring DM: http://www.springframework.org/schema/osgi/spring-osgi.xsd

The following bullets list some of the typical changes you might have to make; the following list is not complete.

When specifying a property to the <osgi:service-property> tag, use the <entry> tag with the key and value attributes, rather than the old <prop> tag. For example, update the following 2.0 tag:

 <osgi:service-properties>
   <prop key="type">SocketAdapterType</prop>
 </osgi:service-properties>

to:

 <osgi:service-properties>
  <entry key="type" value="SocketAdapterType"/>
 </osgi:service-properties>

The value or ref attribute of an instance-property must always be set to an explicit value; it can no longer be an empty string to indicate an implicit use of a default value. For example, update the following 2.0 tag:

 <wlevs:adapter id="fileAdapter" provider="FileAdapterType">
   <!-- file: empty value uses default
   <wlevs:instance-property name="file" value="" />
   <wlevs:listener ref="algoTradingProcessor"/>
  </wlevs:adapter>

to something like the following:

 <wlevs:adapter id="fileAdapter" provider="FileAdapterType">
   <wlevs:instance-property name="file" value="test.file" />
   <wlevs:listener ref="algoTradingProcessor"/>
 </wlevs:adapter>

If, during deployment, you get an exception that indicates that a package is invisible, add this package to the Import-Package header of the MANIFEST.MF file, then reassemble and redeploy the application. Keep adding packages in this manner until the application deploys successfully.

Release Notes