Where to find a NotNull java annotation

Question

I searched for a @NotNull java annotation and found the one from javax. I tried to use it but ran into the same issues described here. In short: I need to set up some stuff to get it working - but I actually don't need all that (I am in plain Java/Groovy context, no JavaEE). Are there alternatives to the mentioned annotation which work standalone, where to find those?

Answer 1

oval can help you with this.

download the jar from http://mvnrepository.com/artifact/net.sf.oval/oval/1.31 and look at the documentation here http://oval.sourceforge.net/

for example:

import net.sf.oval.constraint.MaxLength;
import net.sf.oval.constraint.NotEmpty;
import net.sf.oval.constraint.NotNull;

public class Request {
@NotNull
@NotEmpty
@MaxLength(value = 30)
private String id;
//.....getters setters......
}

above will be your pojo

/**
* Method returns if valid request or not
*/
private boolean isValid(Request request) {
List<ConstraintViolation> violations = validator.validate(request);

if (violations.size() > 0) {
    return false;
} else {
    return true;
}
}

and will do validation like above.

you can also find many more examples online.

Answer 2

You can use the validation quite fine just with groovy. There is the hibernate-validator implementation. e.g.

@Grapes([
        @Grab('javax.validation:validation-api:1.1.0.Final'),
        @Grab('org.glassfish:javax.el:3.0.0'),
        @Grab('org.hibernate:hibernate-validator:5.1.3.Final'),
        ])

import javax.validation.*
import javax.validation.constraints.*

class Pogo {
    @NotNull
    String name

    @NotNull
    @Min(1L)
    Long size
}

def validator = Validation.buildDefaultValidatorFactory().getValidator()
println validator.validate(new Pogo()).collect{ "Error on $it.propertyPath: $it.message" }
//; [Error on name: may not be null, Error on size: may not be null]
println validator.validate(new Pogo(name:"x", size:0)).collect{ "Error on $it.propertyPath: $it.message" }
//; [Error on size: must be greater than or equal to 1]