```
@Target(PARAMETER)
@Retention(CLASS)
@Documented
public @interface Producer
```
Identifies a parameter has the ability to produce a Throwable or a super type of a Throwable. The parameter type must be a Function or a BiFunction.
For a Function the input parameter must be a String which will be the message associated with the method. The result type must Throwable or a super type of a Throwable.

For a BiFunction one of the input parameters must be a String which will be the message associated with the method. The other input parameter must be a Throwable or a super type of a Throwable and must be assignable from the parameter annotated with Cause. The result type must Throwable or a super type of a Throwable.

Example
```
 @Message("The operation failed due to %s")
  T operationFailed(@Producer Function function, String op);

 @Message("The operation failed due to %s")
  T operationFailed(@Producer BiFunction function, @Cause Throwable cause, String op);

 
```
Example Usage
```
 throw Bundle.MESSAGES.operationFailed(IllegalArgumentException::new, "start");

 throw Bundle.MESSAGES.operationFailed(IllegalStateException::new, cause, "start");

 
```
Author:

James R. Perkins

Annotation Type Producer