EMF Validation Constraint Bindings

org.eclipse.emf.validation.constraintBindings

1.0

This extension point allows clients of the EMF Validation framework to define "client contexts" that describe the objects that they are interested in validating, and to bind them to constraints that they are interested in enforcing on these objects.

<!ELEMENT extension (clientContext* , binding*)>

<!ATTLIST extension

point CDATA #REQUIRED

id    CDATA #IMPLIED

name  CDATA #IMPLIED>


<!ELEMENT clientContext (enablement | selector)>

<!ATTLIST clientContext

id      CDATA #REQUIRED

default (true | false) >

Definition of a client context, representing a class of objects that a client wishes to apply a set of constraints to.

A client context can declare an <enablement> expression that matches model elements that are included in the context. Where that is not sufficient, an alternative is to define a selector class using a <selector> element.



<!ELEMENT selector EMPTY>

<!ATTLIST selector

class CDATA #REQUIRED>

A selector determines which model elements are included in a client context when an XML expression is too cumbersome or somehow not sufficient to implement the test.



<!ELEMENT binding (constraint* , category*)>

<!ATTLIST binding

context    CDATA #REQUIRED

constraint CDATA #IMPLIED

category   CDATA #IMPLIED>

Declares a binding between a client context and one or more constraints. The context can, itself, be declared by the same plug-in or by a different plug-in.

The constraints to be bound may be specified by either:



<!ELEMENT constraint EMPTY>

<!ATTLIST constraint

ref CDATA #REQUIRED>

Includes a constraint in a client context <binding>.



<!ELEMENT category EMPTY>

<!ATTLIST category

ref CDATA #REQUIRED>

Includes a constraint category in a client context <binding>. All of the referenced category's constraints and those of any sub-categories (recursively) are included.



<!ELEMENT enablement (not , and , or , instanceof , test , systemTest , equals , count , with , resolve , adapt , iterate)*>

A generic root element. The element can be used inside an extension point to define its enablement expression. The children of an enablement expression are combined using the and operator.



<!ELEMENT not (not | and | or | instanceof | test | systemTest | equals | count | with | resolve | adapt | iterate)>

This element represent a NOT operation on the result of evaluating it's sub-element expression.



<!ELEMENT and (not , and , or , instanceof , test , systemTest , equals , count , with , resolve , adapt , iterate)*>

This element represent an AND operation on the result of evaluating all it's sub-elements expressions.



<!ELEMENT or (not , and , or , instanceof , test , systemTest , equals , count , with , resolve , adapt , iterate)*>

This element represent an OR operation on the result of evaluating all it's sub-element expressions.



<!ELEMENT instanceof EMPTY>

<!ATTLIST instanceof

value CDATA #REQUIRED>

This element is used to perform an instanceof check of the object in focus. The expression returns EvaluationResult.TRUE if the object's type is a sub type of the type specified by the attribute value. Otherwise EvaluationResult.FALSE is returned.



<!ELEMENT test EMPTY>

<!ATTLIST test

property CDATA #REQUIRED

args     CDATA #IMPLIED

value    CDATA #IMPLIED>

This element is used to evaluate the property state of the object in focus. The set of testable properties can be extended using the propery tester extension point. The test expression returns EvaluationResult.NOT_LOADED if teh property tester doing the actual testing isn't loaded yet.



<!ELEMENT systemTest EMPTY>

<!ATTLIST systemTest

property CDATA #REQUIRED

value    CDATA #REQUIRED>

Tests a system property by calling the System.getProperty method and compares the result with the value specified through the value attribute.



<!ELEMENT equals EMPTY>

<!ATTLIST equals

value CDATA #REQUIRED>

This element is used to perform an equals check of the object in focus. The expression returns EvaluationResult.TRUE if the object is equal to the value provided by the attribute value. Otherwise EvaluationResult.FALSE is returned.



<!ELEMENT count EMPTY>

<!ATTLIST count

value CDATA #REQUIRED>

This element is used to test the number of elements in a collection.



<!ELEMENT with (not , and , or , instanceof , test , systemTest , equals , count , with , resolve , adapt , iterate)*>

<!ATTLIST with

variable CDATA #REQUIRED>

This element changes the object to be inspected for all its child element to the object referneced by the given variable. If the variable can not be resolved then the expression will throw a ExpressionException when evaluating it. The children of a with expression are combined using the and operator.



<!ELEMENT resolve (not , and , or , instanceof , test , systemTest , equals , count , with , resolve , adapt , iterate)*>

<!ATTLIST resolve

variable CDATA #REQUIRED

args     CDATA #IMPLIED>

This element changes the object to be inspected for all its child element to the object referneced by the given variable. If the variable can not be resolved then the expression will throw a ExpressionException when evaluating it. The children of a with expression are combined using the and operator.



<!ELEMENT adapt (not , and , or , instanceof , test , systemTest , equals , count , with , resolve , adapt , iterate)*>

<!ATTLIST adapt

type CDATA #REQUIRED>

This element is used to adapt the object in focus to the type specified by the attribute type. The expression returns not loaded if either the adapter or the type referenced isn't loaded yet. It throws a ExpressionException during evaluation if the type name doesn't exist at all. The children of an adapt expression are combined using the and operator.



<!ELEMENT iterate (not , and , or , instanceof , test , systemTest , equals , count , with , resolve , adapt , iterate)*>

<!ATTLIST iterate

operator (or|and) >

This element is used to iterate over a variable that is of type java.util.Collection. If the object in focus is not of type java.util.Collection then an ExpressionException will be thrown while evaluating the expression.



Example of a context which includes EObjects in *.library resources only, not in some other kind of resource that uses the EMF Library example meta-model (utilizing an hypothetical property tester):

   

<extension point=

"org.eclipse.emf.validation.constraintBindings"

>

<clientContext id=

"com.example.MyClient"

>

<enablement>

<with variable=

"resource"

/>

<test property=

"com.example.matchURI"

value=

"*.library"

/>

</with>

</enablement>

</clientContext>

</extension>

Example of a binding of a single constraint to the MyClient context:

   

<extension point=

"org.eclipse.emf.validation.constraintBindings"

>

<binding context=

"com.example.MyClient"

constraint=

"org.eclipse.uml2.validation.classifiers.genCycle"

/>

</extension>

Example of binding multiple constraints and constraint categories to the MyClient context:

   

<extension point=

"org.eclipse.emf.validation.constraintBindings"

>

<binding context=

"com.example.MyClient"

/>

<constraint ref=

"org.eclipse.uml2.validation.namespace.distinctMembers"

/>

<constraint ref=

"org.eclipse.uml2.validation.classifiers.genCycle"

/>

<category ref=

"uml2/spec/classes/kernel/namespaces"

/>

<category ref=

"uml2/spec/classes/kernel/classifiers"

/>

</binding>

</extension>