PropertyConstraint (PMD Core 7.0.0-rc2 API)

Type Parameters:

T - Type of value to handle
```
@Experimental
public interface PropertyConstraint<T>
```
Validates the value of a property.
This interface will change a lot with PMD 7.0.0, because of the switch to Java 8. Please use only the ready-made validators in NumericConstraints for now.

Since:

6.10.0

Author:

Clément Fournier

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`static <U> PropertyConstraint<U>`	`fromPredicate(Predicate<? super U> pred, String constraintDescription)`	Builds a new validator from a predicate, and description.
`String`	`getConstraintDescription()`	Returns a description of the constraint imposed by this validator on the values.
`default boolean`	`test(T t)`
`default PropertyConstraint<Iterable<? extends T>>`	`toCollectionConstraint()`	Returns a constraint that validates a collection of Ts by checking each component conforms to this constraint.
`@Nullable String`	`validate(T value)`	Returns a diagnostic message if the value has a problem.

- Method Detail
  - test
```
default boolean test(T t)
```
  - validate
```
@Nullable String validate(T value)
```
    Returns a diagnostic message if the value has a problem. Otherwise returns an empty optional.
    
    Parameters:
    
    value - The value to validate
    
    Returns:
    
    An optional diagnostic message
  - getConstraintDescription
```
String getConstraintDescription()
```
    Returns a description of the constraint imposed by this validator on the values. E.g. "Should be positive", or "Should be one of A | B | C."
    This is used to generate documentation.
    
    Returns:
    
    A description of the constraint
  - toCollectionConstraint
```
@Experimental
default PropertyConstraint<Iterable<? extends T>> toCollectionConstraint()
```
    Returns a constraint that validates a collection of Ts by checking each component conforms to this constraint.
  - fromPredicate
```
@Experimental
static <U> PropertyConstraint<U> fromPredicate(Predicate<? super U> pred,
                                               String constraintDescription)
```
    Builds a new validator from a predicate, and description.
    
    Type Parameters:
    
    U - Type of value to validate
    
    Parameters:
    
    pred - The predicate. If it returns false on a value, then the value is deemed to have a problem
    
    constraintDescription - Description of the constraint, see getConstraintDescription().
    
    Returns:
    
    A new validator