The predicate bean named shibboleth.BiConditions.Expression executes a Spring Expression Language (SpEL) expression against arbitrary inputs to produce a true/false result.
An Expression Predicate is instantiated by simply supplying a string argument that contains a SpEL expression.
Example
<bean id="MyCondition" parent="shibboleth.BiConditions.Expression" c:expression="#input1 + #input2 < 10" />