The compositional event based modeling of integrated applications (CINEMA) tool provides a way to extend a modeling environment using legacy event based applications, such as Graphical User Interface (GUI) APplications (GAPs). CINEMA allows modelers to extend the toolbox of the modeling environment by creating modeling elements that represent GUI objects of GAPs. CINEMA generates source code that allows an integrated system to control and manipulate the GUI objects of GAPs represented by the modeling elements used to create a model of the integrated system.