On the frontend side there's a form containing a selectbox filled with some options. The model contains a field which will be validated by my custom constraint:
private @Options(values=OptionKeys.SALUTATIONS) String salutation;
Which works great. Now I would like to have checkboxes or a multi value selectbox on the frontend side which uses the following snippet:
private @Options(values=OptionKeys.INTERESTS, optional=true) String[] interests;
Here's the constraint interface and the validator code:
@Target( { METHOD, FIELD, ANNOTATION_TYPE })
@Retention(RUNTIME)
@Constraint(validatedBy = OptionsValidator.class)
@Documented
public @interface Options {
String message() default "{com.example.web.form.constraints.Options.message}";
Class<? extends Payload>[] payload() default {};
Class<?>[] groups() default {};
boolean optional() default false;
OptionKeys values();
}
public class OptionsValidator implements ConstraintValidator<Options, String> {
private List<String> values;
private boolean optional;
@Override
public void initialize(Options params) {
values = Arrays.asList(params.values().data);
optional = params.optional();
}
@Override
public boolean isValid(String value, ConstraintValidatorContext constraintValidatorContext) {
if (optional && StringUtils.isBlank(value)) {
return true;
}
return value != null && values.contains(value);
}
}
public static enum OptionKeys {
SALUTATIONS(new String[] {
"m",
"f"
}),
INTERESTS(new String[] {
"dummy"
});
public final String[] data;
OptionKeys(String[] data) {
this.data = data;
}
}
Is it possible to extend the validator somehow to also check String[]
values or do I have to write another one (eg @MultiOptions
)?
One could use Object
and check its type with instanceof
:
public class OptionsValidator implements ConstraintValidator<Options, Object> {
private List<String> values;
private boolean optional;
@Override
public void initialize(Options params) {
values = Arrays.asList(params.values().data);
optional = params.optional();
}
@Override
public boolean isValid(Object value, ConstraintValidatorContext constraintValidatorContext) {
if (optional && value == null) {
return true;
}
if (value instanceof String[]) {
String[] valArray = (String[]) value;
if (!optional && valArray.length == 0) {
return false;
}
for (String val : valArray) {
if (!values.contains(val)) {
return false;
}
}
return true;
} else if (value instanceof String) {
String val = (String) value;
if (optional && val.trim() == "") {
return true;
}
return val != null && values.contains(val);
}
return false;
}
}
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