Object Constraint Language data
File type: Various data file
Files with ocl file extension contain Object Constraint Language data.
They store textual OCL expressions and constraints used with UML models and other model-based development tools.
File type category:
Various data file
Date updated: October 11, 2026
Object Constraint Language is a declarative language for describing rules that apply to Unified Modeling Language (UML) models. IBM developed the original language, which was later standardized by the Object Management Group (OMG).
An ocl file can contain constraints such as invariants, preconditions, postconditions, and other expressions that define or validate model behavior. It is typically used alongside a UML model rather than as a standalone application file.
Eclipse provides OCL tooling for working with these files on Microsoft Windows, Apple macOS, and Linux. OCL remains used in model-driven engineering and model validation.
Open an ocl file in Eclipse with the appropriate OCL and modeling support installed. Eclipse runs on Microsoft Windows, Apple macOS, and Linux.
A plain-text editor can display the file's contents, but it will not interpret or validate the OCL expressions.
An ocl file normally does not need conversion. It is a text-based collection of constraints, so it can be edited or copied as text. Eclipse OCL tools may process the constraints together with a UML model, but there is no generally required conversion to another file format.
Software apps that create ocl files:
Software applications that handle other tasks involving ocl files:
Language