ValidationRule (md-javadoc 2022.2.0-123-14ca387f API)

All Known Implementing Classes:

DiagramValidator, OpenedDiagramValidator
```
@OpenApiAll
public interface ValidationRule
```
Defines interface for all validation rules. This interface should be implemented by classes that:
1. Want to control whether validation should occur.
2. Want to control what should be validated.
The implementing class must have a public no-arg constructor. If implementing class is designed for validating model elements then implementer of the class must honor project properties:
1. Validation scope
2. Exclude elements from read-only modules
In other words implementer of the class is responsible for correctly implement validating of elements from the specified validation scope and validating or not validating of elements from read-only modules. Also it is responsibility of implementer to detect changes of these properties and providing appropriate validation results. If you need to implement model element validation rule it is more convenient to do by implementing ElementValidationRuleImpl interface.
See Also:

ElementValidationRuleImpl

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`dispose()`	This method will be invoked when instance of the `ValidationRule` will become no longer needed.
`void`	`init(Project project, Constraint constraint)`	This is the first method that is invoked on the implementation of the `ValidationRule` interface.
`boolean`	`needsRun()`	Returns whether the validation rule needs to run.
`java.util.Set<Annotation>`	`run(Project project, Constraint constraint)`	Run the validation.

- Method Detail
  - init
```
void init(Project project,
          @CheckForNull
          Constraint constraint)
```
    This is the first method that is invoked on the implementation of the ValidationRule interface. Implementation can initialize internal state if required.
    
    Parameters:
    
    project - a project of the constraint
    
    constraint - a constraint object
  - needsRun
```
boolean needsRun()
```
    Returns whether the validation rule needs to run.
    
    Returns:
    
    true if validation rule needs to run, otherwise false
  - run
```
java.util.Set<Annotation> run(Project project,
                              @CheckForNull
                              Constraint constraint)
```
    Run the validation.
    
    Parameters:
    
    project - a project of the constraint
    
    constraint - a constraint object
    
    Returns:
    
    set of Annotation objects
  - dispose
```
void dispose()
```
    This method will be invoked when instance of the ValidationRule will become no longer needed.