EsperTech - Esper: Event Stream and Complex Event Processing

Event Stream Processing

• Sliding windows: time, length, sorted, accumulating, time-ordering, externally-timed (value-based windowing)
• Tumbling windows: time, length and multi-policy
• Grouping, aggregation, sorting, filtering and merging of event streams
• Tailored SQL-like query language using insert into, select, from, where, group-by, having and order-by clauses
• Inner-joins and outer joins (left, right, full) of an unlimited number of streams or windows
• Subqueries including exists and in
• Output rate limiting and stabilizing, snapshot output
• Named windows allow sharing data windows between statements; Define multiple explicit entry and exit criteria for events

Event Pattern Matching

• Logical and temporal event correlation
• Crontab-like timer 'at' operator
• Lifecycle of pattern can be controlled by timer and via operators
• Pattern-matched events provided to listeners

Event Representations

• Supports event-type inheritance and polymorphism as provided by the Java language
• Events can be plain Java objects, XML document object model (DOM) and java.util.Map including nested objects
• Event properties can be simple, indexed, mapped or nested - allows querying of deep Java object graphs and XML structures
• Dynamic properties allow dynamic typing of properties, supported by cast, instanceof and exists functions

Prepared statements and substitution parameters

• Precompile a statement with substitution parameters and efficiently start the parameterized statement multiple times

Statement Object Model

• A set of classes providing an object-oriented representation of a statement
• Full and complete specification of a statement via object model
• Round-trip from object model to statement text and back to object model
• Build, change or interrogate statements beyond the textual representation

Input Adapters

• CSV input adapter reads comma-separated value formats
  • simulate multiple event streams with timed, coordinated playback via timestamp column
  • load generator
  • preloading of reference data
• JMS input and output adapter based on Spring JMS templates

Other

• Relational database access via SQL-query joins with event streams
  • LRU (least-recently used) and expiry-time query result caches
  • Keyed cache entries for fast cache lookup
  • Engine indexes cached rows for fast filtering within a large number of SQL-query result rows
• Joins to method invocation allows easy integration with distributed caches, web services and object-oriented databases
• Variables can occur in any expression and can dynamically control output rate
  • Guarantees of consistency and atomicity of variable updates
• Support for both the listener (push/subscription) API and the consumer (pull/receive) API for querying results
• Concurrency-safe iterator provides complete query capability for all statements * Supports externally-provided time as well as Java system time, allowing applications full control over the concept of time within the engine
• Multithread-safe as of release 1.5
  • Multithreaded sends of events into the engine
  • Create, start and stop statements during operation
  • Applications can retain full control over threading
  • Efficiently sharing resources between statements and low thread blocking
• Supports multiple independent Esper engines per JavaVM
• Pluggable architecture for event pattern and event stream analysis via user-defined functions, plug-in views, plug-in aggregation functions, plug-in pattern guards and plug-in pattern event observers, event instance methods
• Unmatched event listener receives a callback if an event does not match any started statement
• Performance-minded design: query strategy analysis and index building; array-based collections; delta networks and many other techniques
  • Benchmark kit available for download; Performance testing results and tips see page in menu

Excellent documentation

Many examples

• J2EE and non-J2EE, from many different domains
• Java Messaging Service (JMS) server shell demonstrates a multi-threaded JMS server with dynamic statement management using Java Management Extensions (JMX)

Supportive user and developer community

Performance tested