Defining Event Expressions

Consider this code snippet from the previous example:

public void onLoad() {
   EventExpression eventExpr =
     new EventExpression("Tick(*, >10.0)");
   eventExpr.addMatchListener(this);
}

The highlighted code is creating an event expression, and embeds the following event expression definition string:

Tick(*, >10.0)

This is the simplest form of an event expression; specifically it contains a single event template.

In this case the event expression is specifying “the first Tick event whose price parameter contains a value greater than 10.0”.

EPL - If you are already familiar with EPL, the syntax for writing Java event expressions is the same as for EPL event expressions.