public void assertNotEmpty(Collection<?> collection, String propertyName) {
        if (CollectionUtils.isNullOrEmpty(collection)) {
            problemReporter.report(new Problem(this, String.format("%s requires one or more items", propertyName)));
        }
    }
Asserts the collection is not null and not empty, reporting to {@link ProblemReporter} with this context if it is.

@param collection   Collection to assert on.
@param propertyName Name of property.
aws-java-sdk-stepfunctions/src/main/java/com/amazonaws/services/stepfunctions/builder/internal/validation/ValidationContext.java