With version 4.2.0 the Imixs-Workflow engine supports conditional events. A conditional event can be defined with one of the BPMN Gateways Exclusive, Inclusive or EventBased.
(workitem._budget && workitem._budget>100)
With Conditional Events, Imixs-BPMN offers a significant extension of the modeling possibilities for BPMN 2.0 models to be executed within the Imixs-Workflow engine. Find further details about the modelling with Imixs-BPMN here.