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package es.jaranda.commons.timeutils.application.properties;

import es.jaranda.commons.timeutils.validations.annotation.TimeZoneFormat;

import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;

public interface TimeRangeContract {
    @NotNull
    @Min(0)
    @Max(23)
    Integer getStartHourOfTimeRange();

    @NotNull
    @Min(0)
    @Max(23)
    Integer getEndHourOfTimeRange();
    
    @NotNull
    @TimeZoneFormat
    String getAppliedTimeZoneForTimeRange();
}

package es.jaranda.commons.timeutils.validations.annotation;

import javax.validation.Constraint;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import javax.validation.Payload;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import java.time.ZoneId;

import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

@Target( { METHOD, FIELD, ANNOTATION_TYPE })
@Retention(RUNTIME)
@Constraint(validatedBy = ValidTimeZoneValidator.class)
public @interface TimeZoneFormat {
    String message() default "Invalid Time-zone ID";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
}

class ValidTimeZoneValidator
        implements ConstraintValidator<TimeZoneFormat, String> {

    @Override
    public void initialize(final TimeZoneFormat constraintAnnotation) {}

    @Override
    public boolean isValid(final String value,
                           final ConstraintValidatorContext context) {
        return value == null || ZoneId.getAvailableZoneIds().contains(value);
    }
}