MDT/New and Noteworthy/1.1

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Model Development Tools Release 1.1 New and Noteworthy Items.

For more details about the development plan, see the MDT 1.1 draft plan.

Back to Modeling Development Tools.


EMF Ontology Definition Metamodel (EODM) Component

EODM 1.0 development has not yet begun. The latest EODM release was 0.9.1 as part of the Europa Winter Maintenance.

Object Constraint Language (OCL) Component

Release 1.2 M6

A few small-ish improvements are made in this milestone, along with a number of bug fixes.

Improved Collection Flattening

The intent of collection flattening in the OCL 2.0 Specification is to produce collections in the same form as OCL 1.x, in which collections could not nest. OCL 2.0 does allow collections to contain other collections, so the flatten() operation is provided to reduce a nested structure to a flat collection.

Through the 1.1 release, the flatten() implementation in MDT OCL has been incorrect: only the first level of nesting is flattened. A Set(Set(Set(Apple))) would be reduced to a Bag(Set(Apple)) instead of a Bag(Apple). This is corrected by bug 217461. After all, a partially-flattened collection isn't really of any use at all.

Implementing an EValidator

The OCL.uml model was updated to add all of the well-formedness constraints specified by OCL for the Types and Expressions packages of the Abstract Syntax. These are documented using the OCL expressions included in the OCL 2.0 Specification. From these constraint specifications, the TypesValidator and ExpressionsValidator are generated as per the EMF validation framework.

This provided the basis for resolving two bugs in the Ecore binding plug-in:

  • bug 213936 for validation extensibility (the currrent visitor design is not extensible) and
  • bug 213096 to override the ENamedElement::WellFormedName constraint from Ecore, which doesn't apply to OCL.

The latter is accomplished by overriding the inherited constraints in an EcoreValidator generated in the OCL binding for Ecore.

The well-formedness rules implemented in the ValidationVisitor are not yet ported to the new validators. This is planned for the next milestone, in bug 224731.

Other Bug Fixes

For other bug fixes, see the OCL 1.2 M6 release notes.

Release 1.2 M5

Development in this milestone was limited to bug fixing.

See the OCL 1.2 M5 release notes for details.

Release 1.2 M4

This was not an ambitious milestone, for the most part simply fixing defects and making one or two small enhancements. A few changes are worth noting because of their impact on API and, in some cases, compatibility with the 1.1 release.

Disposing OCL Environments

A new disposal API is defined for the OCL façade that does whatever is necessary to "clean up" the objects created by the parser, such as constraints, collection types, and variables. More specifically, disposing an OCL instance currently does the following:

  • if the resource in which the environment (variables, collection types, etc.) is persisted was created by the environment and not by a client (to load an existing environment), then that resource is unloaded
  • all Constraints that are not contained in a resource have their adapter lists cleared, recursively over their contents

These measures are particularly important for the UML metamodel binding. In the course of parsing and evaluating OCL expressions, the UML2 API's CacheAdapter will become attached to constraints and other objects created by the parser. It is important that this adapter be removed again from any object that is no longer in use, because otherwise it will retain that object indefinitely (the CacheAdapter is a singleton).

Additional Look-up Exceptions

Two specializations of the LookupException are added to distinguish between ambiguous look-ups and invalid look-ups. The AmbiguousLookupException signals a look-up that resulted in multiple matches that the parser cannot distinguish and the InvalidLookupException signals a look-up that resulted in an unambiguous match that is of the wrong metatype than what is required. For example, a qualified-name look-up for a Classifier or a QVT Transformation might find a Package instead of an instance of the expected metatype.

The Ecore and UML implementations of the Environment are updated to throw these more specific exception types.

Changes in Parsing Behaviour

Two further changes were implemented in the OCL parser's behaviour that have an impact on compatibility with the 1.1 release. These address Bug 197396 and Bug 212804. The former improves the parser's compliance with the OCL specification of definition constraints; compatibility with the 1.1 release is available by enabling the ParsingOptions::DEFINITION_CONSTRAINS_FEATURE option. The latter eliminates an obsolete mapping of the relational operators (< <= >= >) to the Java-ish compareTo() operation; compatibility with the 1.1 release is available by enabling the ParsingOptions::USE_COMPARE_TO_OPERATION option.

Other Bug Fixes

For other bug fixes, see the OCL 1.2 M4 release notes.

Release 1.2 M3

OCL Grammar and Parser API Refactoring

This milestone delivers the long-awaited refactoring of the OCL LPG grammar and associated parser API, contributed by Ed Willink from the GMT project's UMLX component.

The major new API in this contribution is defined in the org.eclipse.ocl.lpg and org.eclipse.ocl.parser packages. Included is an implementation of an EssentialOCL grammar (EssentialOCL.g) which is included in the full grammar (OCLParser.g). The former OCLParser class (which was internal) is refactored to separate the concrete syntax and abstract syntax parsing phases, implemented by the public classes OCLParser and [1] OCLAnalyzer, respectively.

Abstract LPG-parsing API is provided by the org.eclipse.ocl.lpg package, with abstract definitions of lexers, parsers, and analyzers. These are accompanied by a BasicEnvironment interface that provides core services such as a new pluggable ProblemHandler for flexible reporting of parsing/analysis problems.

See Bug 176110 for further details.

Navigation of Unnamed Association Ends

The UML metamodel binding now supports parsing and evaluation of OCL expressions that navigate unnamed association ends. The OCL convention for unnamed ends defines an implicit name which is the name of the classifier at that end with the initial letter in lower case. MDT OCL supports evaluation of such navigation expressions, where the implicit end name is unambiguous, on:

instances of UML2-generated metamodels:

Navigating unnamed metamodel association ends

and on instance specifications in UML models:

Navigating unnamed model association ends

Other New API

As part of the refactoring of the parser API, this milestone introduces some new optional interfaces that environments may choose to implement. To maintain API compatibility, OCL employs an optional Adaptable interface similar to Eclipse Platform's IAdaptable that is available is stand-alone deployments. The OCLUtil class provides utilities to obtain adapters from parsing and evaluation environments for these optional interfaces.

One noteworthy new optional interface is Customizable, which defines a protocol for customizing the parsing and evaluation of OCL constraints via Options. Parsing options available so far include:

Evaluation options available so far include:

Other Bug Fixes

For other bug fixes, see the OCL 1.2 M3 release notes.

OCL Tools Component

OCL Tools is a recently added component to the Model Development Tools (MDT) Project aiming at providing first-class support to modelers working with specifications containing expressions written in OCL, the Object Constraint Language. Such support includes editing, refactoring, code generation, execution, and interactive debugging of the OCL constraints given for some underlying (Ecore or UML2) class model. The functionality of OCL Tools builds upon the MDT OCL component, and has been seeded with two initial contributions:

  • an OCL -> Java compiler, that as of now takes as input an .ecore and a textual file containing OCL constraints (handling UML2 is in the ToDo list). This compiler extends EMF code generation, producing Java 5 source code with side-effects-free methods for the given OCL invariants, pre- and postconditions, and derived attributes and operations.
  • an OCL text editor, supporting usability features such as AutoCompletion, navigation by means of hyperlinks, structured views (for the outline of a document and for the Abstract Syntax Tree of an OCL constraint), among others. Although MDT OCL itself is completely fluent in both Ecore and UML2, only the Ecore binding is supported by the OCL text editor at this time.

A longer intro to OCL Tools can be found at

Unified Modeling Language 2.x (UML2) Component

Release 2.2 M7

The M7 milestone focused mainly on bug fixing.

One area that was scrutinized was: package merge. It was discovered that the existing package merge algorithm could result in infinite looping if users incorrectly created circular dependencies on packages or if the resulting merge resulted in circular inheritance chains. The code was made more robust by detecting such cycles and stopping in such cases. This will have impact on users wishing to create DSL's using package merge concepts.

Fixes include:

  • Bug 228754 UML models do not open properly if there is a circular inheritance chain
  • Bug 229338 Package merge could result in infinite looping

Another nagging issue that was addressed was the fact that users could get concurrent modification exceptions when unloading resources as a result of the cache adapter not being thread safe.

  • Bug 220065 ConcurrentModificationException when unloading resources

Other notable fixes:

  • Bug 227892 Can't load model with references made using hierarchical URI fragments

Release 2.2 M6

  • Support for camel case names was added: Camel Case
  • Content types for CMOF and UML resources has been added. This will help associate the appropriate default editors with their respective resources.

Release 2.2 M5

  • Users now have the ability to save a UML model in a .CMOF or .XMI format.
    • Invoke the 'File > Save As...' menu item and specify a file with a .cmof extension.
    • To open a .cmof file with the UML editor, select the file in the explorer view and select 'Open With > UML Editor' from the context menu.

Sample UML Model:


Internals of UML Model:


"Save As ..." menu


"Save As" dialog


Internals of CMOF file.


Other defects: UML 2.2 M5 release notes

Release 2.2 M4

This milestone consisted mostly of fixing some defects and making few small enhancements. A few changes are worth noting.

Code template changes

The Javadoc for the UML2 API now contains information about subsetting and redefinition. Such information is useful when trying to navigate the maze of properties and how the UML meta-model is put together.

For example, Package::nestedPackage subsets Package::packagedElement


Profile registry

A new profile registry has been added making the discovery of profiles easier.

Add support for registering dynamic profiles

Release 2.2 M3

Programmers Guide Updates

A programmers guide has been added to the UML2 component. Minor content has been added with the expectation that richer documentation and articles will be added in the future.

UML2 Tools Component


XML Schema Infoset (XSD) Component

Release 2.4 M7

  • Several performance and usability improvements, including
  • Reduction of the number of objects created when parsing a XSD file
  • Performance improvements when validating big elements
  • Reduction of the memory footprint due to the use of the packaged Enum feature introduced in EMF 2.4 (see bug 226815)

Release 2.4 M6

This milestone consisted mostly of fixing some defects and making few small enhancements. See details.

Release 2.4 M5

This milestone consisted mostly of fixing some defects and making few small enhancements. See details.

Release 2.4 M4

This milestone (and those prior) consisted mostly of fixing some defects and making few small enhancements. See details.

One change is worth noting.

Support ecore:suppressSubstitutionGroups

See details here and in bug 211820. See also Exploiting Substitution Groups Without Polluting Your Generated API.