AmericanExpressWhen (Conditional Validator - Implementation for Apache BVal 0.0.3 API)

@Documented
@Target({METHOD,FIELD,ANNOTATION_TYPE,CONSTRUCTOR,PARAMETER})
@Retention(RUNTIME)
public @interface AmericanExpressWhen

- Required Element Summary
  
  Required Elements
  Modifier and Type Required Element Description
  
  String expression
- Optional Element Summary
  
  Optional Elements
  Modifier and Type Optional Element Description
  
  Class<?>[] groups
  
  String message
  
  Class<? extends javax.validation.Payload>[] payload

- Element Detail
  - expression
```
String expression
```
- - message
```
String message
```
    Default:
    
    "{org.apache.bval.extras.constraints.creditcard.AmericanExpress.message}"
- - groups
```
Class<?>[] groups
```
    Default:
    
    {}
- - payload
```
Class<? extends javax.validation.Payload>[] payload
```
    Default:
    
    {}