public BeanDescriptor getConstraintsForClass()
Return the class level constraints
The returned object (and associated objects including ConstraintDescriptors)
are immutable.

 public PropertyDescriptor getConstraintsForProperty(String propertyName)
Return the property level constraints for a given propertyName
or null if either the property does not exist or has no constraint
The returned object (and associated objects including ConstraintDescriptors)
are immutable.

 public Set getPropertiesWithConstraints()
return the property names having at least a constraint defined

 public boolean hasConstraints()
return true if at least one constraint declaration is present for the given bean
or if one property is marked for validation cascade

 public Set validate(T object,
    String groups)
validate all constraints on object

 public Set validateProperty(T object,
    String propertyName,
    String groups)
validate all constraints on <code>propertyName</code> property of object

 public Set validateValue(String propertyName,
    Object value,
    String groups)
validate all constraints on propertyName property
if the property value is value

TODO express limitations of ConstraintViolation in this case