MoDisco/Components/J2SE5

The J2SE5 meta model : it is the reflect of Java language, as it has been defined in version 3 of "Java Language Specification" from Sun Microsystems ("JLS3" corresponds to JDK 5).

J2SE5 meta model contains 101 meta classes. To better understand it, this page will introduce main features (meta classes and links).

You could also browse definition model, j2se5.ecore available in sources (see install section).

A good tip is also to see javadoc associated to meta model implemented by Eclipse team in project JDT (Java Development Tool). This meta model and J2SE5 are very similar.

Main meta classes

ASTNode

Every meta classes (without meta class Model) inherit from ASTNode. As its name indicate it, ASTNode represent a graph node. ASTNode has a reference to Comment meta class because almost every java element could be associated to a comment (bloc or line comment and Javadoc). More details in "Comment" section.

ASTNode meta class

Model, Package, AbstractTypeDeclaration

Root element of each J2SE5 model in an instance of "Model" meta class. It is a translation of java application concept, so it contains package declarations (instances of PackageDeclaration meta class). And package declarations contain type declarations (instances compatible with AbstractTypeDeclaration meta class), and so on ...

Model, Package & type declaration super class

NamedElement & notion of Proxy

A lot of java elements are "named", and this name could be considered as an identifier : methods, packages, types, variables, fields, ... So all of corresponding meta classes inherit from NamedElement meta class. It will be usefull to resolve references in binding, see NamedElementRef meta class.

And an other goal of this meta class is to indicate which element is a part of the current java application or not (element from an external library of from JDK). Then external elements are tagged as proxy through dedicated attribute and could be easily filtered. For example, instruction "System.out.println" has been decomposed in three named elements (one class, one variable and one method) which defintion are not part of current java application. So attribute "proxy" of these elements has been initialized as true.

NamedElement and its hierarchy

NamedElementRef

To represent links between java elements, as java AST defines only string references, meta class NamedElementRef initially contained only this information. But an important addition was to resolve binding between elements, so is is actually possible to navigate directly in elements graph. It has been represented through a relationship from a NamedElementRef to a NamedElement (proxy or not).

NamedElementRef

BodyDeclaration

A type declaration has different kinds of contents : fields, methods, static block, initialization block or other type declarations. All of these elements are of type BodyDeclaration meta class.

BodyDeclaration and its hierarchy

Expressions

Like in many languages, concept of expression exists in Java : it is a portion of code, without declarations, and its evaluation returns a value, numerical or boolean or other ...

For example,

++i

is an expression and will be translated in concept of PrefixExpression meta class.

All types of expressions shall inherit from Expression meta class.

Expression and its hierarchy

Statements

An "instruction" in Java is represented by Statement meta class. A block of code (Block meta class) contains a collection of statements, an a block of code may be contained by a method.

Some example of statements in java :

if, while, for, do, ...

All of their definitions use concept of expression to separate value from instruction keyword.

Statement and its hierarchy

Requirements

To use the plug-in you need:

• JDK 1.5 or above
• a version of Eclipse 3.3 or above with the following set of plugins installed

• EMF 2.3.0 or higher

Install

You will find a version of this plug-in attached in following bug.

As IP review of this plugin is not finished, here is installation instructions :

• Extract archive file in your Eclipse workspace, then use "import" menu to import this project.
• Use "export" menu to export this project as a plugin (Deployable plugins and fragments) in your Eclipse installation. Don't forget to choose "Package plug-ins as individual jar archives" option.
• re-start your Eclipse to take in account this plug-in