I've got a simple REST resource which accepts a couple of query parameters. I'd like to validate one of these parameters, and came across ConstraintValidator for this purpose. The REST resource expects the query param territoryId to be a UUID, so I'd like to validate that it indeed is a valid UUID.
I've created an #IsValidUUID annotation, and a corresponding IsValidUUIDValidator (which is a ConstraintValidator). With what I have now, nothing gets validated and getSuggestions accepts anything I throw at it. So clearly I'm doing something wrong.
What am I doing wrong?
The REST resource now looks like this :
#Component
#Path("/search")
public class SearchResource extends AbstractResource {
#GET
#Path("/suggestions")
#Produces(MediaType.APPLICATION_XML)
public Response getSuggestions(
#QueryParam("phrase") List<String> phrases,
#IsValidUUID #QueryParam("territoryId") String territoryId) {
[...]
}
}
IsValidUUID
#Target({ElementType.TYPE, ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})
#Retention(RetentionPolicy.RUNTIME)
#Documented
#Constraint(validatedBy = {IsValidUUIDValidator.class})
public #interface IsValidUUID {
String message() default "Invalid UUID";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
IsValidUUIDValidator
public class IsValidUUIDValidator implements ConstraintValidator<IsValidUUID, String> {
#Override
public void initialize(IsValidUUID constraintAnnotation) {
}
#Override
public boolean isValid(String value, ConstraintValidatorContext context) {
if (value == null) {
return true;
}
try {
UUID.fromString(value);
return true;
} catch (Exception e) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate("The provided UUID is not valid")
.addConstraintViolation();
return false;
}
}
}
You need to set the supported targets on IsValidUUID, using the following annotation.
#SupportedValidationTarget(ValidationTarget.ANNOTATED_ELEMENT)
or
#SupportedValidationTarget(ValidationTarget.PARAMETERS)
Edit:
Sorry, I wasn't able to make it work either on a RequestParam directly. However, if you can, try creating a POJO that you can bind your request parameters to and annotate the binding field with your constraint instead. This worked for me.
public class MyModel {
#IsValidUUID
private String territoryId;
public String getTerritoryId() {
return territoryId;
}
public void setTerritoryId(String territoryId) {
this.territoryId = territoryId;
}
}
#GET
#Path("/suggestions")
#Produces(MediaType.APPLICATION_XML)
public Response getSuggestions(
#QueryParam("phrase") List<String> phrases,
#Valid #ModelAttribute MyModel myModel) {
[...]
}
I'm looking for a clean way to handle Jackson Deserialization errors for REST web requests.
More precisely: I have an Enum in a incoming DTO object, mapped from JSON. But if the user sends a wrong value, a 400 Bad Request is returned. I would like to return a 422 Unprocessable Entity with a correct message.
One option would be to accept a String, and use bean validation. However, it's not possible to pass all enum values as a list to the annotation (not a constant), so I would need to pass all enum values separately and keep them up to date. This will be very error prone over the whole application. I'm looking for a more structural way to handle this.
I solved this by using a String in the DTO and using a public #interface EnumValueas annotation.
The EnumValue:
#ReportAsSingleViolation
#Documented
#Retention(RetentionPolicy.RUNTIME)
#Constraint(validatedBy = EnumValueValidator.class)
#Target(ElementType.FIELD)
public #interface EnumValue {
Class<? extends Enum> value();
String message() default "The input contains validation errors.";
Class<?>[] groups() default { };
Class<? extends Payload>[] payload() default { };
}
The validator:
public class EnumValueValidator implements ConstraintValidator<EnumValue, String> {
private Class<? extends Enum> enumClass;
private String message;
#Override
public void initialize(final EnumValue constraintAnnotation) {
this.enumClass = constraintAnnotation.value();
this.message = constraintAnnotation.message();
}
#Override
public boolean isValid(final String value, final ConstraintValidatorContext context) {
boolean valid = false;
for (final Enum enumValue : enumClass.getEnumConstants()) {
if (enumValue.name().equals(value)) {
valid = true;
}
}
if (!valid) {
context.buildConstraintViolationWithTemplate(message) //
.addConstraintViolation();
}
return valid;
}
}
Can I use #Autowired Spring 4.x #Components with a #ConditionalOnProperty to choose implementations of a Feature based on a featuretoggles.properties file?
public class Controller {
#Autowired
private Feature feature;
}
#Component
#ConditionalOnProperty(name = "b", havingValue = "off")
public class A implements Feature {
}
#Component
#ConditionalOnProperty(name = "b", havingValue = "on")
public class B implements Feature {
}
#Configuration
#PropertySource("classpath:featuretoggles.properties")
public class SomeRandomConfig {
}
With a src/main/resources/featuretoggles.properties file:
b = on
(That the name of the toggle "b" and the name of the class "B" match is coincidence; it's not my aim to have these equal, the toggle could have any name.)
This fails to auto-wire feature in the Controller with an UnsatisfiedDependencyException, saying "No qualifying bean of type 'Feature' available: expected at least 1 bean that qualifies as autowire candidate".
I know I can realize this with a #Configuration class that chooses a #Bean depending on the property. But when I do that I have to add a new Configuration class each time I add a feature toggle, and those Configuration classes will be highly similar:
#Configuration
#PropertySource("classpath:featuretoggles.properties")
public class FeatureConfig {
#Bean
#ConditionalOnProperty(name = "b", havingValue = "on")
public Feature useB() {
return new B();
}
#Bean
#ConditionalOnProperty(name = "b", havingValue = "off")
public Feature useA() {
return new A();
}
}
I did what you're trying to do by following this guide. First step was to write a Condition...
public class OnEnvironmentPropertyCondition implements Condition
{
#Override
public boolean matches(ConditionContext ctx, AnnotatedTypeMetadata meta)
{
Environment env = ctx.getEnvironment();
Map<String, Object> attr = meta.getAnnotationAttributes(
ConditionalOnEnvProperty.class.getName());
boolean shouldPropExist = (Boolean)attr.get("exists");
String prop = (String)attr.get("value");
boolean doesPropExist = env.getProperty(prop) != null;
// doesPropExist shouldPropExist result
// true true true
// true false false
// false true false
// true false true
return doesPropExist == shouldPropExist;
}
}
...then an annotation using that condition.
/*
* Condition returns true if myprop exists:
* #ConditionalOnEnvProperty("myprop")
*
* Condition returns true if myprop does not exist
* #ConditionalOnEnvProperty(value="myprop", exists=false)
*/
#Target({ElementType.TYPE, ElementType.METHOD})
#Retention(RetentionPolicy.RUNTIME)
#Conditional(OnEnvironmentPropertyCondition.class)
public #interface ConditionalOnEnvProperty
{
public String value();
public boolean exists() default true;
}
You can add featuretoggles.properties to the environment with the #PropertySource annotation.
I'm trying to use something similar to org.springframework.cache.annotation.Cacheable :
Custom annotation:
#Target(ElementType.METHOD)
#Retention(RetentionPolicy.RUNTIME)
#Documented
public #interface CheckEntity {
String message() default "Check entity msg";
String key() default "";
}
Aspect:
#Component
#Aspect
public class CheckEntityAspect {
#Before("execution(* *.*(..)) && #annotation(checkEntity)")
public void checkEntity(JoinPoint joinPoint, CheckEntitty checkEntity) {
System.out.println("running entity check: " + joinPoint.getSignature().getName());
}
}
Service:
#Service
#Transactional
public class EntityServiceImpl implements EntityService {
#CheckEntity(key = "#id")
public Entity getEntity(Long id) {
return new Entity(id);
}
}
My IDE (IntelliJ) doesn't see anything special with the key = "#id" usage in contrast to similar usages for Cacheable where it's shown with different color than plain text. I'm mentioning the IDE part just as a hint in case it helps, it looks like the IDE is aware in advance about these annotations or it just realizes some connection which doesn't exist in my example.
The value in the checkEntity.key is '#id' instead of an expected number.
I tried using ExpressionParser but possibly not in the right way.
The only way to get parameter value inside the checkEntity annotation is by accessing the arguments array which is not what I want because this annotation could be used also in methods with more than one argument.
Any idea?
Adding another simpler way of doing it using Spring Expression. Refer below:
Your Annotation:
#Target(ElementType.METHOD)
#Retention(RetentionPolicy.RUNTIME)
#Documented
public #interface CheckEntity {
String message() default "Check entity msg";
String keyPath() default "";
}
Your Service:
#Service
#Transactional
public class EntityServiceImpl implements EntityService {
#CheckEntity(keyPath = "[0]")
public Entity getEntity(Long id) {
return new Entity(id);
}
#CheckEntity(keyPath = "[1].otherId")
public Entity methodWithMoreThanOneArguments(String message, CustomClassForExample object) {
return new Entity(object.otherId);
}
}
class CustomClassForExample {
Long otherId;
}
Your Aspect:
#Component
#Aspect
public class CheckEntityAspect {
#Before("execution(* *.*(..)) && #annotation(checkEntity)")
public void checkEntity(JoinPoint joinPoint, CheckEntitty checkEntity) {
Object[] args = joinPoint.getArgs();
ExpressionParser elParser = new SpelExpressionParser();
Expression expression = elParser.parseExpression(checkEntity.keyPath());
Long id = (Long) expression.getValue(args);
// Do whatever you want to do with this id
// This works for both the service methods provided above and can be re-used for any number of similar methods
}
}
PS: I am adding this solution because I feel this is a simpler/clearner approach as compared to other answers and this might be helpful for someone.
Thanks to #StéphaneNicoll I managed to create a first version of a working solution:
The Aspect
#Component
#Aspect
public class CheckEntityAspect {
protected final Log logger = LogFactory.getLog(getClass());
private ExpressionEvaluator<Long> evaluator = new ExpressionEvaluator<>();
#Before("execution(* *.*(..)) && #annotation(checkEntity)")
public void checkEntity(JoinPoint joinPoint, CheckEntity checkEntity) {
Long result = getValue(joinPoint, checkEntity.key());
logger.info("result: " + result);
System.out.println("running entity check: " + joinPoint.getSignature().getName());
}
private Long getValue(JoinPoint joinPoint, String condition) {
return getValue(joinPoint.getTarget(), joinPoint.getArgs(),
joinPoint.getTarget().getClass(),
((MethodSignature) joinPoint.getSignature()).getMethod(), condition);
}
private Long getValue(Object object, Object[] args, Class clazz, Method method, String condition) {
if (args == null) {
return null;
}
EvaluationContext evaluationContext = evaluator.createEvaluationContext(object, clazz, method, args);
AnnotatedElementKey methodKey = new AnnotatedElementKey(method, clazz);
return evaluator.condition(condition, methodKey, evaluationContext, Long.class);
}
}
The Expression Evaluator
public class ExpressionEvaluator<T> extends CachedExpressionEvaluator {
// shared param discoverer since it caches data internally
private final ParameterNameDiscoverer paramNameDiscoverer = new DefaultParameterNameDiscoverer();
private final Map<ExpressionKey, Expression> conditionCache = new ConcurrentHashMap<>(64);
private final Map<AnnotatedElementKey, Method> targetMethodCache = new ConcurrentHashMap<>(64);
/**
* Create the suitable {#link EvaluationContext} for the specified event handling
* on the specified method.
*/
public EvaluationContext createEvaluationContext(Object object, Class<?> targetClass, Method method, Object[] args) {
Method targetMethod = getTargetMethod(targetClass, method);
ExpressionRootObject root = new ExpressionRootObject(object, args);
return new MethodBasedEvaluationContext(root, targetMethod, args, this.paramNameDiscoverer);
}
/**
* Specify if the condition defined by the specified expression matches.
*/
public T condition(String conditionExpression, AnnotatedElementKey elementKey, EvaluationContext evalContext, Class<T> clazz) {
return getExpression(this.conditionCache, elementKey, conditionExpression).getValue(evalContext, clazz);
}
private Method getTargetMethod(Class<?> targetClass, Method method) {
AnnotatedElementKey methodKey = new AnnotatedElementKey(method, targetClass);
Method targetMethod = this.targetMethodCache.get(methodKey);
if (targetMethod == null) {
targetMethod = AopUtils.getMostSpecificMethod(method, targetClass);
if (targetMethod == null) {
targetMethod = method;
}
this.targetMethodCache.put(methodKey, targetMethod);
}
return targetMethod;
}
}
The Root Object
public class ExpressionRootObject {
private final Object object;
private final Object[] args;
public ExpressionRootObject(Object object, Object[] args) {
this.object = object;
this.args = args;
}
public Object getObject() {
return object;
}
public Object[] getArgs() {
return args;
}
}
I think you probably misunderstand what the framework is supposed to do for you vs. what you have to do.
SpEL support has no way to be triggered automagically so that you can access the actual (resolved) value instead of the expression itself. Why? Because there is a context and as a developer you have to provide this context.
The support in Intellij is the same thing. Currently Jetbrains devs track the places where SpEL is used and mark them for SpEL support. We don't have any way to conduct the fact that the value is an actual SpEL expression (this is a raw java.lang.String on the annotation type after all).
As of 4.2, we have extracted some of the utilities that the cache abstraction uses internally. You may want to benefit from that stuff (typically CachedExpressionEvaluator and MethodBasedEvaluationContext).
The new #EventListener is using that stuff so you have more code you can look at as examples for the thing you're trying to do: EventExpressionEvaluator.
In summary, your custom interceptor needs to do something based on the #id value. This code snippet is an example of such processing and it does not depend on the cache abstraction at all.
Spring uses internally an ExpressionEvaluator to evaluate the Spring Expression Language in the key parameter (see CacheAspectSupport)
If you want to emulate the same behaviour, have a look at how CacheAspectSupport is doing it. Here is an snippet of the code:
private final ExpressionEvaluator evaluator = new ExpressionEvaluator();
/**
* Compute the key for the given caching operation.
* #return the generated key, or {#code null} if none can be generated
*/
protected Object generateKey(Object result) {
if (StringUtils.hasText(this.metadata.operation.getKey())) {
EvaluationContext evaluationContext = createEvaluationContext(result);
return evaluator.key(this.metadata.operation.getKey(), this.methodCacheKey, evaluationContext);
}
return this.metadata.keyGenerator.generate(this.target, this.metadata.method, this.args);
}
private EvaluationContext createEvaluationContext(Object result) {
return evaluator.createEvaluationContext(
this.caches, this.metadata.method, this.args, this.target, this.metadata.targetClass, result);
}
I don't know which IDE you are using, but it must deal with the #Cacheable annotation in a different way than with the others in order to highlight the params.
Your annotation can be used with methods with more than 1 parameter, but that doesn't mean you can't use the arguments array. Here's a sollution:
First we have to find the index of the "id" parameter. This you can do like so:
private Integer getParameterIdx(ProceedingJoinPoint joinPoint, String paramName) {
MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();
String[] parameterNames = methodSignature.getParameterNames();
for (int i = 0; i < parameterNames.length; i++) {
String parameterName = parameterNames[i];
if (paramName.equals(parameterName)) {
return i;
}
}
return -1;
}
where "paramName" = your "id" param
Next you can get the actual id value from the arguments like so:
Integer parameterIdx = getParameterIdx(joinPoint, "id");
Long id = joinPoint.getArgs()[parameterIdx];
Of course this assumes that you always name that parameter "id". One fix there could be to allow to specify the parameter name on the annotation, something like
#Target(ElementType.METHOD)
#Retention(RetentionPolicy.RUNTIME)
#Documented
public #interface CheckEntity {
String message() default "Check entity msg";
String key() default "";
String paramName() default "id";
}
Hi am using hibernate validator in jersey rest service.
Here how can we pass value to the property file message as follows
empty.check= Please enter {0}
here in {0} i need to pass the value from annotation
#EmptyCheck(message = "{empty.check}") private String userName
here in the {0} i need to pass "user name", similarly i need to reuse message
please help me out to solve this.
You can do this by altering your annotation to provide a field description and then exposing this in the validator.
First, add a description field to your annotation:
#Target({ FIELD, METHOD, PARAMETER, ANNOTATION_TYPE })
#Retention(RetentionPolicy.RUNTIME)
#Constraint(validatedBy = EmptyCheckValidator.class)
#Documented
public #interface EmptyCheck {
String description() default "";
String message() default "{empty.check}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
Next, change your message so that it uses a named parameter; this is more readable.
empty.check= Please enter ${description}
Since you're using hibernate-validator, you can get the hibernate validator context within your validation class and add a context variable.
public class EmptyCheckValidator
implements ConstraintValidator<EmptyCheck, String> {
String description;
public final void initialize(final EmptyCheck annotation) {
this.description = annotation.description();
}
public final boolean isValid(final String value,
final ConstraintValidatorContext context) {
if(null != value && !value.isEmpty) {
return true;
}
HibernateConstraintValidatorContext ctx =
context.unwrap(HibernateConstraintValidatorContext.class);
ctx.addExpressionVariable("description", this.description);
return false;
}
}
Finally, add the description to the field:
#EmptyCheck(description = "a user name") private String userName
This should produce the following error when userName is null or empty:
Please enter a user name