In the Apama EPL first steps blog, we explored the basic concepts and constructs used to create EPL programs. In this blog, we will build upon this and look at some more advanced features of the EPL language, namely those around sending and receiving events, as well as extending our knowledge of filtering specific patterns of events.
Sending and receiving
We know that EPL can process incoming events with a listener, but where do these events come from?… Read More
One of the common questions we hear about Apama, and EPL, is: “How can I create derived classes?” The naive answer is “you can’t” – but let’s dig a little deeper.
First off, a little bit of background. Apama EPL doesn’t have classes – it has events. An event can have both data and methods (actions) but it is not a class. Among other things, this means that you can’t directly extend or inherit an event.… Read More
The latest version of Apama Community Edition has arrived bringing many improvements including new connectivity options, usability improvements for Apama queries and enhancements to EPL.… Read More
EPL Memory profiling is about investigating and analyzing an Apama application’s behavior to aid in optimizations for better memory usage and identifying any leaks. Apama’s capability to profile the EPL memory usage does provide a handy mechanism to identify any listener or object leaks used in the application within the correlator. Identifying such leaks could otherwise be a daunting task for any developer.
Note : Usage of the memory profiler is recommended during the development or debugging of an EPL application but, not when in production since it impacts the performance of the application.… Read More
The latest release of Apama Community Edition provides a new connectivity plug-in which is a transport allowing the Apama correlator to access REST or other web services. The transport is a client for other webservices, rather than allowing the correlator to act as a web service itself. In order to use the HTTP client transport you need to configure a chain within the connectivity system using the correlator configuration YAML. This chain provides the mapping between Apama events inside the correlator and HTTP requests/responses to the external web service.… Read More
Hopefully you will have seen our webinar which gave an insight into the type of applications that can be built rapidly with Apama Community Edition – if not – you can see it here. This post serves as an aid alongside that, briefly describing the application that was shown and supplying links to help you get started so that you can download, run and begin expanding and changing it to suit your needs.… Read More