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The Eclipse OCL Project provides an implementation of the Object Constraint Language (OCL) OMG standard for EMF-based models.

The Core OCL component provides the following capabilities to support OCL integration:

  • Defines APIs for parsing and evaluating OCL constraints and queries on EMF models.
  • Defines Ecore and UML implementations of the OCL abstract syntax model, including support for serialization of parsed OCL expressions.
  • Provides a Visitor API for analyzing/transforming the AST model of OCL expressions.
  • Provides an extensibility API for clients to customize the parsing and evaluation environments used by the parser.

The Core OCL parser is generated by the LALR Parser Generator, a SourceForge project, licensed under the EPL v1.0. Download it from the LPG home page. This site includes the generator executable required to regenerate the parser code.

The additional OCL Examples and Editors component provides interactive support for OCL:

  • Provides an Interactive OCL Console to evaluate queries on models.
  • Provides an OCLinEcore Xtext editor for OCL embedded in an Ecore meta-model.
  • Provides a CompleteOCL editor for an OCL document complementing a meta-model.
  • Provides an EssentialOCL editor for individual OCL expressions.

The grammars for the Xtext-based editors auto-generate ANTLR parsers. In Eclipse OCL 3.0, the ANTLR parsers are used solely within the editors. As from Eclipse OCL 3.1 the Xtext grammars and parsers provide full evaluation and validation capabilities too. Since the Xtext grammars are associated with a re-engineering to support a model-defined standard library and full OMG compliance, the original LPG parser will be increasingly deprecated.

Downloads and Updates

For Users

Eclipse OCL may be installed directly from the main Eclipse http://download.eclipse.org/releases/neon/ Update Site.

or from an OCL-specific site: http://download.eclipse.org/modeling/mdt/ocl/updates. The Eclipse OCL Repositories and Updates for Milestone, Interim and Nightly builds are described in P2 Repositories Organization and retained in accordance with the Retention Policy.

The OCL Examples and Editors SDK feature provides the full IDE comprising Xtext-based editors, Interactive Console, Debugger and Java Code Generator all using the new Unified Pivot -based OCL.

The OCL End User SDK feature provides the Classic OCL support with distinct Ecore and UML APIs.

Eclipse OCL may be installed indirectly by downloading an archive ZIP from Project Downloads and then using the downloaded ZIP as the Works with site for Help->Install New Software...

Eclipse OCL has Open Bugs and a newsgroup or forum. See the OCL Forum Netiquette.

For Developers

An Eclipse OCL development environment may be created automatically using the OOMPH Eclipse Installer. Follow the OOMPH instructions to first create an Eclipse installation with a Java VM, then invoke File->Import Projects->Oomph->Projects into Workspace->Eclipse Projects->OCL->Development. After a few minutes the required dependencies have been downloaded and a restart is required. Then after a few tens of minutes the required GIT repositories have been cloned and you are ready to go; there should be no errors in the Problems View. You may wish to select Working Sets as the top level elements in the Package Explorer. You may Run->Run Configurations...->JUnit->org.eclipse.ocl.examples.xtext.tests (standalone) to demonstrate that the standard tests are passing.

Alternatively an Eclipse OCL development environment may be created manually using the Eclipse OCL source code from git://git.eclipse.org/c/ocl/org.eclipse.ocl.git, http://git.eclipse.org/c/ocl/org.eclipse.ocl.git and github Network. All source projects may be installed by Import...->Team->Team Project Set, then entering http://git.eclipse.org/c/ocl/org.eclipse.ocl.git/plain/releng/org.eclipse.ocl.releng/psfs/ocl-all.psf?h=master as the URL for import. Be patient; the repository clone takes a while, and there are no obvious progress indicators during the third phase while projects are actually created.

If you plan to contribute to Eclipse OCL, please have a look to the project Developer Resources

Documentation, Publications and FAQs

Example Code

Releases and Development

You may want to check the New and Noteworthy features of the Eclipse OCL releases.


API Changes

  • API Changes made in the Helios Eclipse OCL release.
  • API Changes made in the Indigo Eclipse OCL release.
  • Deprecations announced in the Juno Eclipse OCL release.
  • Limitations of the Ecore/UML bindings and OCL 2.3 compared to the Pivot binding and 'OCL 2.5'.


The remainder of this section has links to pages of interest primarily to those developing the OCL component.

Development Environment

Release Engineering

Related Links