An event pattern matches when a single event or multiple events that match the pattern definition occur. Patterns can also be described based on time.
Pattern expressions consist of pattern atoms and pattern operators.
Pattern atoms contain filter expressions and observers for time-based events. Filter expressions specify filter conditions for event streams.
There are the following four types of pattern operators:
Operators that control repetitions of the subexpressions that comprise the pattern expression: EVERY, EVERY-DISTINCT, [COUNT], UNTIL
Logical operators: AND, OR, NOT
Time operator that operates event sequences: -> (followed-by)
Guards specified in WHERE clauses for controlling subexpression life cycles: TIMER:WITHIN, TIMER:WITHINMAX, WHILE expression
