Adding @NotNull or Pattern constraints on List<String>

Question

How can we ensure the individual strings inside a list are not null/blank or follow a specific pattern

@NotNull
List<String> emailIds;

I also want to add a pattern

@Pattern("\b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}\b.")

but I can live without it.But I would definitely like to have a constraint which will check if any strings inside a list are null or blank. Also how would the Json schema look like

"ids": {
      "description": "The  ids associated with this.", 
    "type": "array",
        "minItems": 1,
        "items": {
        "type": "string",
         "required" :true }
 }

"required" :true does not seem to do the job

Answer 1

Bean validation 2.0 (Hibernate Validator 6.0.1 and above) supports validating container elements by annotating type arguments of parameterized types. Example:

List<@Positive Integer> positiveNumbers;

Or even (although a bit busy):

List<@NotNull @Pattern(regexp="\\b[A-Z0-9._%+-]+@[A-Z0-9.-]+.[A-Z]{2,4}\\b") String> emails;

References:

• http://beanvalidation.org/2.0/
• https://docs.jboss.org/hibernate/stable/validator/reference/en-US/html_single/#_with_code_list_code