Esper release 2.1

The Esper team is happy to announce release 2.1 now available. This release has added significant new features and enhanced existing ones. Please find the change log below.

Special thanks to Paul Fremantle of WSO2 that contributed streaming XML event type based on Apache Axiom. Also thanks for Jerry Shea that contributed nano-time resolution as well as EsperIO enhancements. Any other unmentioned supporters also deserve a thanks.

We have a further upcoming announcement that our inward-facing JDBC driver is available for GA, to be publicly available this week. This local and remote driver adds standards-based access for charting and reporting to real-time data within Esper.

Best regards,
Tom

Major API changes
  - New API to plug-in of a custom event type
  - Added additional sendEvent method that accepts alias name and event object, plus EventSender instance to skip type lookup     
    
New Features
  - Added support for variant event streams, into which events of disparate event types can be inserted and treated as the same type
  - Added support for update events (aka. version or revision events)
  - Added support for streaming XML using Apache Axiom
  - Added support for EsperIO CSV adapter to send bean events
  - Allowed normalization of subevents into resultant stream     
  - Allowed DOM-type property of XML events transpose into new stream for use with XPath and nested syntax     

Minor changes                
  - Properties can now be prefixed by the engine URI and the event type alias used in the from-clause; Event streams can be prefixed by the engine URI (SQL compatibility)
  - Added full support for nano/microsecond resolution
  - Allowed access to statement's XPathFactory instance to supply XPathFunctionResolver, etc.     
  - Added support for an escape syntax for event property names that contain dots
  - Allowed esperio to use external timer
  - Added support to specify a time period in output rate limiting     
  - Added support for the "in" operator to accept array properties, collection (set, list) property or map property for contains-value semantics     
  - Now uses thread ClassLoader for compatilibility with OSGi
  - Provide additional XPath return value types to cast to     
  - Allow certain keywords to be used as column alias, such as "select count(*) as count from foo"
  - Fixed issue ESPER-197 EsperIO/CSV reported to be slow     
  - Fixed issue ESPER-208 Esperio runs out of stack space when processing largeCSV file and not using engine thread     
  - Fixed issue ESPER-209 Stop of consumer statements of named windows may not entirely deregister consumer     
  - Fixed issue ESPER-213 ConcurrentModificationException creating consuming statements to a single named window under threading     
  - Fixed issue ESPER-214 ClassCastException in named window dispatch for timer thread when multiple insert-into     
  - Fixed issue ESPER-219 Documentation for plug-in views not specifying implicit contract towards object references     
  - Fixed issue ESPER-220 TimeBatchView.computeWaitMSec can give incorrect results for low "interval"     
  - Fixed issue ESPER-221 Named window with batch expiry policy causes late consumers to post incorrect data or throw IllegalArgumentException
  - Fixed issue ESPER-227 No documentation on time-batch view parameter for reference point
  - Fixed issue ESPER-228 PDF document page number not showing