Fennec OCL — Generic EMF Editor Support: Installation Guide

This guide explains how to install the Fennec OCL Eclipse integration and how to make the generic (reflective) EMF editor evaluate OCL annotations — invariant constraints, derived‑feature derivations and operation bodies — with the Fennec OCL engine.

The integration is shipped as an Eclipse p2 repository packaged into a single JAR (org.eclipse.fennec.m2x.ocl.p2). That JAR is published to Maven Central (releases) and Central Snapshots and can be added to Eclipse directly as an archive repository — no separate update site needs to be hosted.

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1. Prerequisites

• Eclipse with EMF installed (any Modeling package, or a base Eclipse with the EMF SDK / EMF — Eclipse Modeling Framework SDK feature). Verified against Eclipse 2026‑06.
• Java 21 runtime for Eclipse.
• That's it. EMF (org.eclipse.emf.ecore/common/xmi), the OSGi framework and Declarative Services (org.apache.felix.scr) are all part of such an Eclipse and are used as‑is — they are not bundled by this feature. The feature ships only the Fennec OCL bundles, the Fennec emf.osgi API and the ANTLR runtime.

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2. Install from the update site (recommended)

The p2 repository is published as a live GitHub Pages update site — a stable URL you simply add in Eclipse, with no download:

https://eclipse-fennec.github.io/emf.m2x/ocl/snapshot/p2/

In Eclipse: Help → Install New Software… → Add… → Location: paste the URL → tick Fennec OCL → install → restart.

The path carries the branch/version: …/ocl/<branch>/p2/. Today the development branch snapshot is published; once the first release is cut, a stable …/ocl/latest/p2/ alias (tracking main) is added — prefer that for production.

This is the easiest option and supports normal Check for Updates. The Maven archive below (§3) is an alternative for offline/pinned installs.

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3. Get the p2 archive (alternative)

The same repository is also a normal Maven artifact whose JAR is a p2 repository.

groupId	org.eclipse.fennec.m2x
artifactId	org.eclipse.fennec.m2x.ocl.p2
packaging	jar (a self‑contained p2 repository)

Snapshot (Sonatype Central Snapshots) — current development builds:

https://central.sonatype.com/repository/maven-snapshots/org/eclipse/fennec/m2x/org.eclipse.fennec.m2x.ocl.p2/0.1.1-SNAPSHOT/

Snapshot JARs are timestamped; the directory's maven-metadata.xml names the latest one, e.g.:

.../0.1.1-SNAPSHOT/org.eclipse.fennec.m2x.ocl.p2-0.1.1-<timestamp>-<n>.jar

You can either download that JAR (§3, Method A) or point Eclipse straight at it with the jar:…!/ URL (§3, Method B) — that works for snapshots too, e.g.:

jar:https://central.sonatype.com/repository/maven-snapshots/org/eclipse/fennec/m2x/org.eclipse.fennec.m2x.ocl.p2/0.1.1-SNAPSHOT/org.eclipse.fennec.m2x.ocl.p2-0.1.1-<timestamp>-<n>.jar!/

Note the URL pins one timestamped build, so it doesn't auto‑update — use the GitHub Pages update site (§2) if you want Check for Updates.

Release (Maven Central) — once a release is published:

https://repo1.maven.org/maven2/org/eclipse/fennec/m2x/org.eclipse.fennec.m2x.ocl.p2/<version>/org.eclipse.fennec.m2x.ocl.p2-<version>.jar

Releases have stable file names, so the direct jar:…!/ URL (§3, Method B) works without a download. Substitute <version> (e.g. 0.1.1).

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Install the archive in Eclipse

Method A — local archive (works for releases and snapshots)

1. Download the org.eclipse.fennec.m2x.ocl.p2-<version>.jar.
2. In Eclipse: Help → Install New Software… → Add… → Archive…
3. Select the downloaded JAR. (The JAR is itself a p2 repository, so Eclipse reads content.jar/artifacts.jar straight from inside it.)
4. Tick the Fennec OCL category, Next, accept the EPL‑2.0 license, Finish.
5. Restart Eclipse when prompted.

Method B — direct jar: URL (releases and snapshots, no download)

In Help → Install New Software… → Add…, set Location to the JAR wrapped as a p2 archive URL (note the leading jar: and trailing !/). Eclipse reads the p2 metadata straight from inside the remote JAR — no download needed.

Release (stable file name):

jar:https://repo1.maven.org/maven2/org/eclipse/fennec/m2x/org.eclipse.fennec.m2x.ocl.p2/<version>/org.eclipse.fennec.m2x.ocl.p2-<version>.jar!/

Snapshot (timestamped file name from maven-metadata.xml):

jar:https://central.sonatype.com/repository/maven-snapshots/org/eclipse/fennec/m2x/org.eclipse.fennec.m2x.ocl.p2/0.1.1-SNAPSHOT/org.eclipse.fennec.m2x.ocl.p2-0.1.1-<timestamp>-<n>.jar!/

Then proceed as in Method A from step 4.

Updating to a newer version: Fennec OCL releases use a new version number each time, so a normal Install/Update picks them up cleanly. Snapshots all map to the same p2 version (x.y.z.SNAPSHOT), so when testing snapshots uninstall the previously installed "Fennec OCL" first (see §7) before re‑installing.

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4. Enable OCL on your Ecore model

The generic editor only evaluates OCL where the model asks for it. Add the delegate wiring to your .ecore:

a) On the EPackage — declare which delegate URI handles each delegate kind (EAnnotation source http://www.eclipse.org/emf/2002/Ecore):

detail key	value
settingDelegates	http://www.eclipse.org/fennec/m2x/ocl/1.0
invocationDelegates	http://www.eclipse.org/fennec/m2x/ocl/1.0
validationDelegates	http://www.eclipse.org/fennec/m2x/ocl/1.0

b) On the model elements — put the OCL text in an EAnnotation whose source is the Fennec URI http://www.eclipse.org/fennec/m2x/ocl/1.0:

Where	detail key	example value
derived EStructuralFeature (set derived/volatile/transient)	derivation	self.name.size()
EOperation	body	'Hello, '.concat(self.name)
EClass (+ list the names in an …/Ecore annotation under key constraints)	<constraintName>	self.age > 0

Legacy Eclipse OCL models work too. The same delegates are also registered under the Eclipse OCL Pivot URI http://www.eclipse.org/emf/2002/Ecore/OCL/Pivot, so models already annotated for Eclipse OCL are evaluated by the Fennec engine without changes.

A ready‑to‑use example lives at company.ecore (and company-eclipse-ocl.ecore for the Pivot URI variant) in the repository root.

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5. Use it in the generic editor

1. Open your .ecore, right‑click an EClass → Create Dynamic Instance…, save the .xmi.
2. Open the .xmi in the Sample Reflective Ecore Model Editor (the default generic editor).
3. Set the stored attributes (e.g. name, age). In the Properties view the derived features (e.g. nameLength) now show their computed values.
4. Validate: right‑click the root object → Validate. Invariant violations are reported as diagnostics (e.g. set age = -5 to trip agePositive).

Notes:

• Operation bodies are evaluated when the operation is invoked programmatically (eInvoke); the reflective tree editor has no UI to call operations directly.
• If a derivation evaluates to invalid (e.g. self.name.size() while name is null), the feature is shown empty — same behaviour as Eclipse OCL.

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6. Verify the integration is active

In the OSGi console (or Host OSGi Console):

headers org.eclipse.fennec.m2x.ocl.ide

The Bundle-SymbolicName must read org.eclipse.fennec.m2x.ocl.ide;singleton:=true. The bundle normally sits in state STARTING (it uses lazy activation) and only turns ACTIVE the first time EMF asks it for a delegate (first derived‑feature read or validation) — that is expected, not an error.

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7. Troubleshooting

"Cannot complete the install … requires 'org.eclipse.emf.ecore…' could not be found". Your target Eclipse has no EMF. Install an EMF/Modeling package or the EMF SDK feature first, then retry.

Nothing is evaluated in the editor (derived features blank, Validate does nothing).

• Confirm the bundle is present and singleton (see §6). The Eclipse extension registry only reads a bundle's plugin.xml if it is singleton:=true.
• Confirm your model carries the package‑level settingDelegates / validationDelegates / invocationDelegates annotations and the per‑element OCL annotations under the Fennec (or Pivot) URI (see §4).
• Check Window → Show View → Error Log for an exception thrown while a delegate is first used.

A rebuilt snapshot doesn't take effect after re‑install. Snapshot bundles all share the p2 version x.y.z.SNAPSHOT, so p2 keeps the copy already in the shared bundle pool. Fully uninstall the old "Fennec OCL" (Help → About → Installation Details → Installed Software → Uninstall), restart with -clean, then install the new archive. Released versions (distinct version numbers) do not have this issue.

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8. Uninstall

Help → About Eclipse → Installation Details → Installed Software → select Fennec OCL → Uninstall…, then restart.

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Appendix — building the p2 archive yourself

From the bnd workspace (workspace/):

./gradlew :org.eclipse.fennec.m2x.ocl.ide:jar
./gradlew :org.eclipse.fennec.m2x.ocl.ide.p2:export --rerun-tasks

The repository JAR is written to org.eclipse.fennec.m2x.ocl.ide.p2/generated/org.eclipse.fennec.m2x.ocl.p2.jar and can be added to Eclipse via Add… → Archive… exactly like the published one.