The purpose of validators is to impose restrictions on the property values to be filled in by the user. The most common one is the so called 'Required field validator', which can be applied to any property model, regardless of its type. By applying this validator, the user ensures that all property instances based on this model will provide a warning while no value is filled in. An example of the difference between a property that satisfies a 'Required field validator' and one that doesn't can be observed below.
Figure 1 - Rendering of a property with a 'Required field validator' whose value has not been filled in. Red triangle flag signals there is an unsatisfied validator. The message appears on hover.
Figure 2 - Rendering of a property with a 'Required field validator' whose value has been filled in. Message is gone, as well as the red flag.
The second and last introduced validator (as of release 2.14.0) is the 'Numeric field validator'. This validator can only be applied on Integer and Decimal number property types. This validator accepts three inputs, all three optional:
The values the property can take are thus limited between the minimum and maximum specifications. The stepsize allows for the property value to be increased or decreased using the arrows with increments other than 1.
Figure 3 - Rendering of a property with a 'Numeric field validator' whose value is larger than its 'maximum value' specified. Red triangle flag signals there is an unsatisfied validator. The message appears on hover.