Type Parameters:

T - the class of the input value

All Known Implementing Classes:

NotNullValidator, NumberValidator, PositiveNumberValidator, RequiredValidator
```
public interface Validator<T>
```
An interface for providing validation of an input value.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`default Validator<T>`	`add(Validator<T> other)`	Apply another validation after this validation.
`default Validator<T>`	`add(Validator<T> other, java.lang.String separator)`	Apply another validation after this validation.
`static <T> Validator<T>`	`empty()`
`default Validator<T>`	`then(Validator<T> other)`	Apply another validation if this validation passes.
`java.lang.String`	`validate(T value)`	Validate a value.
`default Validator<T>`	`when(java.util.function.Supplier<java.lang.Boolean> condition)`
`default Validator<T>`	`whenNot(java.util.function.Supplier<java.lang.Boolean> condition)`

- Method Detail
  - empty
```
static <T> Validator<T> empty()
```
  - validate
```
java.lang.String validate(T value)
```
    Validate a value.
    
    Parameters:
    
    value - the value to validate
    
    Returns:
    
    a description of the validation errors or null
  - when
```
default Validator<T> when(java.util.function.Supplier<java.lang.Boolean> condition)
```
    Returns:
    
    a new Validator that only reports errors when the condition is true
  - whenNot
```
default Validator<T> whenNot(java.util.function.Supplier<java.lang.Boolean> condition)
```
    Returns:
    
    a new Validator that only reports errors when the condition is false
  - then
```
default Validator<T> then(Validator<T> other)
```
    Apply another validation if this validation passes.
    
    Parameters:
    
    other - the other validator
    
    Returns:
    
    a new Validator that returns the error from this or other
  - add
```
default Validator<T> add(Validator<T> other)
```
    Apply another validation after this validation. Uses System.lineSeparator() as the message separator.
    
    Parameters:
    
    other - the other validator
    
    Returns:
    
    a new Validator that returns the combined messages of this and other
  - add
```
default Validator<T> add(Validator<T> other,
                         java.lang.String separator)
```
    Apply another validation after this validation.
    
    Parameters:
    
    other - the other validator
    
    separator - the separator to use when joining the error messages
    
    Returns:
    
    a new Validator that returns the combined messages of this and other

Interface Validator<T>

Method Summary

Method Detail

empty

validate

when

whenNot

then

add

add