keyGenerator not work on spel key,may I custom keyGenerator for all key contains #Cacheable(key="#spelKey")
I found code: org.springframework.cache.interceptor.CacheAspectSupport
protected Object generateKey(Object result) {
if (StringUtils.hasText(this.metadata.operation.getKey())) {
EvaluationContext evaluationContext = this.createEvaluationContext(result);
return CacheAspectSupport.this.evaluator.key(this.metadata.operation.getKey(), this.methodCacheKey, evaluationContext);
} else {
return this.metadata.keyGenerator.generate(this.target, this.metadata.method, this.args);
}
}
change code like：
protected Object generateKey(Object result) {
if (StringUtils.hasText(this.metadata.operation.getKey())) {
EvaluationContext evaluationContext = createEvaluationContext(result);
return this.metadata.keyGenerator.generate(this.target, this.metadata.method, evaluator.key(this.metadata.operation.getKey(), this.methodCacheKey, evaluationContext));
}
return this.metadata.keyGenerator.generate(this.target, this.metadata.method, this.args);
}
I am not sure what you're trying to do with #spelKey but it's fairly documented. If you want to do something complex, I'd implement a KeyGenerator instead, see the documentation
Related
When can redis hasKey method return null? I have seen that if we pass null also in method param it returns false .So is there any scenario when that method can return null?
If you use spring data redis,It mainly includes the following situations
Key does not exist；
After pipline；
After transaction execution
you can take a look at the underlying implementation org. Springframework. Data. Redis. Connection. Jedis. Jediskeycommands #exists (byte []...). Detail as following:
#Override
public Boolean hasKey(K key) {
byte[] rawKey = rawKey(key);
return execute(connection -> connection.exists(rawKey), true);
}
#Nullable
#Override
public Long exists(byte[]... keys) {
Assert.notNull(keys, "Keys must not be null!");
Assert.noNullElements(keys, "Keys must not contain null elements!");
try {
if (**isPipelined**()) {
pipeline(connection.newJedisResult(connection.getRequiredPipeline().exists(keys)));
return **null**;
}
if (**isQueueing**()) {
transaction(connection.newJedisResult(connection.getRequiredTransaction().exists(keys)));
return **null**;
}
return connection.getJedis().exists(keys);
} catch (Exception ex) {
throw connection.convertJedisAccessException(ex);
}
}
I am writing a person API using Spring WebFlux functional programming, how to route to different handler functions based on the query param names?
#Bean
public RouterFunction<ServerResponse> route(PersonHandler personHandler) {
return RouterFunctions.route(GET("/people/{id}").and(accept(APPLICATION_JSON)), personHandler::get)
.andRoute(GET("/people").and(accept(APPLICATION_JSON)), personHandler::all)
.andRoute(GET("/people/country/{country}").and(accept(APPLICATION_JSON)), personHandler::getByCountry)
// .andRoute(GET("/people?name={name}").and(accept(APPLICATION_JSON)), personHandler::searchByName)
// .andRoute(GET("/people?age={age}").and(accept(APPLICATION_JSON)), personHandler::searchByAge)
// I am expecting to do something like this
;
}
Or do I need to handle it in the handler function?
like
public Mono<ServerResponse> searchPeople(ServerRequest serverRequest) {
final Optional<String> name = serverRequest.queryParam("name");
final Optional<String> age = serverRequest.queryParam("age");
Flux<People> result;
if(name.isPresent()){
result = name.map(peopleRepository::searchByName)
.orElseThrow();
} else if(age.isPresent()){
result = name.map(peopleRepository::searchByage)
.orElseThrow();
}
return ok().contentType(MediaType.APPLICATION_JSON).body(result, People.class);
}
What is the best way to do it?
Thanks
You can create your own RequestPredicate and use the existing infrastructure (by plugging it into a and()):
public static RequestPredicate hasQueryParam(String name) {
return RequestPredicates.queryParam(name, p -> StringUtils.hasText(p));
}
I am using spring-boot 1.4.0 and hibernate-validator 5.2.0. I have a model which contains custom validator inside the custom validator i want to check whether the property value is a valid URL for that i need to call URLValidator in hibernate but no luck.Could anyone please guide me to resolve this issue
CustomValidator.java
#Component
public class BookValidator extends GenericValidator<Book, ConstraintValidatorContext> implements ConstraintValidator<ValidBooks, List<Book>> {
public BookValidator() {
addValidators();
}
private void addValidators() {
getValidators().add((book, context) -> {
boolean isValid = book.getUrl(); //here i want to check against Hibernate URL validator
if (!isValid) {
context.disableDefaultConstraintViolation();
context
.buildConstraintViolationWithTemplate("Book URL should be valid!")
.addConstraintViolation();
}
return isValid;
});
}
#Override
public void initialize(ValidBooks constraintAnnotation) {
}
}
How can i check whether the URL is a valid one
boolean isValid = book.getUrl(); using hibernate URLValidator?
This works:
AnnotationDescriptor<URL> descriptor = new AnnotationDescriptor<URL>( URL.class );
URL url = AnnotationFactory.create(descriptor);
URLValidator urlValidator = new URLValidator();
urlValidator.initialize(url);
boolean isValid = urlValidator.isValid(book.getUrl(), context);
I'm using the gemfire-json-server module in SpringXD to populate a GemFire grid with json representation of “Order” objects. I understand the gemfire-json-server module saves data in Pdx form in GemFire. I’d like to read the contents of the GemFire grid into an “Order” object in my application. I get a ClassCastException that reads:
java.lang.ClassCastException: com.gemstone.gemfire.pdx.internal.PdxInstanceImpl cannot be cast to org.apache.geode.demo.cc.model.Order
I’m using the Spring Data GemFire libraries to read contents of the cluster. The code snippet to read the contents of the Grid follows:
public interface OrderRepository extends GemfireRepository<Order, String>{
Order findByTransactionId(String transactionId);
}
How can I use Spring Data GemFire to convert data read from the GemFire cluster into an Order object?
Note: The data was initially stored in GemFire using SpringXD's gemfire-json-server-module
Still waiting to hear back from the GemFire PDX engineering team, specifically on Region.get(key), but, interestingly enough if you annotate your application domain object with...
#JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "#type")
public class Order ... {
...
}
This works!
Under-the-hood I knew the GemFire JSONFormatter class (see here) used Jackson's API to un/marshal (de/serialize) JSON data to and from PDX.
However, the orderRepository.findOne(ID) and ordersRegion.get(key) still do not function as I would expect. See updated test class below for more details.
Will report back again when I have more information.
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = GemFireConfiguration.class)
#SuppressWarnings("unused")
public class JsonToPdxToObjectDataAccessIntegrationTest {
protected static final AtomicLong ID_SEQUENCE = new AtomicLong(0l);
private Order amazon;
private Order bestBuy;
private Order target;
private Order walmart;
#Autowired
private OrderRepository orderRepository;
#Resource(name = "Orders")
private com.gemstone.gemfire.cache.Region<Long, Object> orders;
protected Order createOrder(String name) {
return createOrder(ID_SEQUENCE.incrementAndGet(), name);
}
protected Order createOrder(Long id, String name) {
return new Order(id, name);
}
protected <T> T fromPdx(Object pdxInstance, Class<T> toType) {
try {
if (pdxInstance == null) {
return null;
}
else if (toType.isInstance(pdxInstance)) {
return toType.cast(pdxInstance);
}
else if (pdxInstance instanceof PdxInstance) {
return new ObjectMapper().readValue(JSONFormatter.toJSON(((PdxInstance) pdxInstance)), toType);
}
else {
throw new IllegalArgumentException(String.format("Expected object of type PdxInstance; but was (%1$s)",
pdxInstance.getClass().getName()));
}
}
catch (IOException e) {
throw new RuntimeException(String.format("Failed to convert PDX to object of type (%1$s)", toType), e);
}
}
protected void log(Object value) {
System.out.printf("Object of Type (%1$s) has Value (%2$s)", ObjectUtils.nullSafeClassName(value), value);
}
protected Order put(Order order) {
Object existingOrder = orders.putIfAbsent(order.getTransactionId(), toPdx(order));
return (existingOrder != null ? fromPdx(existingOrder, Order.class) : order);
}
protected PdxInstance toPdx(Object obj) {
try {
return JSONFormatter.fromJSON(new ObjectMapper().writeValueAsString(obj));
}
catch (JsonProcessingException e) {
throw new RuntimeException(String.format("Failed to convert object (%1$s) to JSON", obj), e);
}
}
#Before
public void setup() {
amazon = put(createOrder("Amazon Order"));
bestBuy = put(createOrder("BestBuy Order"));
target = put(createOrder("Target Order"));
walmart = put(createOrder("Wal-Mart Order"));
}
#Test
public void regionGet() {
assertThat((Order) orders.get(amazon.getTransactionId()), is(equalTo(amazon)));
}
#Test
public void repositoryFindOneMethod() {
log(orderRepository.findOne(target.getTransactionId()));
assertThat(orderRepository.findOne(target.getTransactionId()), is(equalTo(target)));
}
#Test
public void repositoryQueryMethod() {
assertThat(orderRepository.findByTransactionId(amazon.getTransactionId()), is(equalTo(amazon)));
assertThat(orderRepository.findByTransactionId(bestBuy.getTransactionId()), is(equalTo(bestBuy)));
assertThat(orderRepository.findByTransactionId(target.getTransactionId()), is(equalTo(target)));
assertThat(orderRepository.findByTransactionId(walmart.getTransactionId()), is(equalTo(walmart)));
}
#Region("Orders")
#JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "#type")
public static class Order implements PdxSerializable {
protected static final OrderPdxSerializer pdxSerializer = new OrderPdxSerializer();
#Id
private Long transactionId;
private String name;
public Order() {
}
public Order(Long transactionId) {
this.transactionId = transactionId;
}
public Order(Long transactionId, String name) {
this.transactionId = transactionId;
this.name = name;
}
public String getName() {
return name;
}
public void setName(final String name) {
this.name = name;
}
public Long getTransactionId() {
return transactionId;
}
public void setTransactionId(final Long transactionId) {
this.transactionId = transactionId;
}
#Override
public void fromData(PdxReader reader) {
Order order = (Order) pdxSerializer.fromData(Order.class, reader);
if (order != null) {
this.transactionId = order.getTransactionId();
this.name = order.getName();
}
}
#Override
public void toData(PdxWriter writer) {
pdxSerializer.toData(this, writer);
}
#Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof Order)) {
return false;
}
Order that = (Order) obj;
return ObjectUtils.nullSafeEquals(this.getTransactionId(), that.getTransactionId());
}
#Override
public int hashCode() {
int hashValue = 17;
hashValue = 37 * hashValue + ObjectUtils.nullSafeHashCode(getTransactionId());
return hashValue;
}
#Override
public String toString() {
return String.format("{ #type = %1$s, id = %2$d, name = %3$s }",
getClass().getName(), getTransactionId(), getName());
}
}
public static class OrderPdxSerializer implements PdxSerializer {
#Override
public Object fromData(Class<?> type, PdxReader in) {
if (Order.class.equals(type)) {
return new Order(in.readLong("transactionId"), in.readString("name"));
}
return null;
}
#Override
public boolean toData(Object obj, PdxWriter out) {
if (obj instanceof Order) {
Order order = (Order) obj;
out.writeLong("transactionId", order.getTransactionId());
out.writeString("name", order.getName());
return true;
}
return false;
}
}
public interface OrderRepository extends GemfireRepository<Order, Long> {
Order findByTransactionId(Long transactionId);
}
#Configuration
protected static class GemFireConfiguration {
#Bean
public Properties gemfireProperties() {
Properties gemfireProperties = new Properties();
gemfireProperties.setProperty("name", JsonToPdxToObjectDataAccessIntegrationTest.class.getSimpleName());
gemfireProperties.setProperty("mcast-port", "0");
gemfireProperties.setProperty("log-level", "warning");
return gemfireProperties;
}
#Bean
public CacheFactoryBean gemfireCache(Properties gemfireProperties) {
CacheFactoryBean cacheFactoryBean = new CacheFactoryBean();
cacheFactoryBean.setProperties(gemfireProperties);
//cacheFactoryBean.setPdxSerializer(new MappingPdxSerializer());
cacheFactoryBean.setPdxSerializer(new OrderPdxSerializer());
cacheFactoryBean.setPdxReadSerialized(false);
return cacheFactoryBean;
}
#Bean(name = "Orders")
public PartitionedRegionFactoryBean ordersRegion(Cache gemfireCache) {
PartitionedRegionFactoryBean regionFactoryBean = new PartitionedRegionFactoryBean();
regionFactoryBean.setCache(gemfireCache);
regionFactoryBean.setName("Orders");
regionFactoryBean.setPersistent(false);
return regionFactoryBean;
}
#Bean
public GemfireRepositoryFactoryBean orderRepository() {
GemfireRepositoryFactoryBean<OrderRepository, Order, Long> repositoryFactoryBean =
new GemfireRepositoryFactoryBean<>();
repositoryFactoryBean.setRepositoryInterface(OrderRepository.class);
return repositoryFactoryBean;
}
}
}
So, as you are aware, GemFire (and by extension, Apache Geode) stores JSON in PDX format (as a PdxInstance). This is so GemFire can interoperate with many different language-based clients (native C++/C#, web-oriented (JavaScript, Pyhton, Ruby, etc) using the Developer REST API, in addition to Java) and also to be able to use OQL to query the JSON data.
After a bit of experimentation, I am surprised GemFire is not behaving as I would expect. I created an example, self-contained test class (i.e. no Spring XD, of course) that simulates your use case... essentially storing JSON data in GemFire as PDX and then attempting to read the data back out as the Order application domain object type using the Repository abstraction, logical enough.
Given the use of the Repository abstraction and implementation from Spring Data GemFire, the infrastructure will attempt to access the application domain object based on the Repository generic type parameter (in this case "Order" from the "OrderRepository" definition).
However, the data is stored in PDX, so now what?
No matter, Spring Data GemFire provides the MappingPdxSerializer class to convert PDX instances back to application domain objects using the same "mapping meta-data" that the Repository infrastructure uses. Cool, so I plug that in...
#Bean
public CacheFactoryBean gemfireCache(Properties gemfireProperties) {
CacheFactoryBean cacheFactoryBean = new CacheFactoryBean();
cacheFactoryBean.setProperties(gemfireProperties);
cacheFactoryBean.setPdxSerializer(new MappingPdxSerializer());
cacheFactoryBean.setPdxReadSerialized(false);
return cacheFactoryBean;
}
You will also notice, I set the PDX 'read-serialized' property (cacheFactoryBean.setPdxReadSerialized(false);) to false in order to ensure data access operations return the domain object and not the PDX instance.
However, this had no affect on the query method. In fact, it had no affect on the following operations either...
orderRepository.findOne(amazonOrder.getTransactionId());
ordersRegion.get(amazonOrder.getTransactionId());
Both calls returned a PdxInstance. Note, the implementation of OrderRepository.findOne(..) is based on SimpleGemfireRepository.findOne(key), which uses GemfireTemplate.get(key), which just performs Region.get(key), and so is effectively the same as (ordersRegion.get(amazonOrder.getTransactionId();). The outcome should not be, especially with Region.get() and read-serialized set to false.
With the OQL query (SELECT * FROM /Orders WHERE transactionId = $1) generated from the findByTransactionId(String id), the Repository infrastructure has a bit less control over what the GemFire query engine will return based on what the caller (OrderRepository) expects (based on the generic type parameter), so running OQL statements could potentially behave differently than direct Region access using get.
Next, I went onto try modifying the Order type to implement PdxSerializable, to handle the conversion during data access operations (direct Region access with get, OQL, or otherwise). This had no affect.
So, I tried to implement a custom PdxSerializer for Order objects. This had no affect either.
The only thing I can conclude at this point is something is getting lost in translation between Order -> JSON -> PDX and then from PDX -> Order. Seemingly, GemFire needs additional type meta-data required by PDX (something like #JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "#type") in the JSON data that PDXFormatter recognizes, though I am not certain it does.
Note, in my test class, I used Jackson's ObjectMapper to serialize the Order to JSON and then GemFire's JSONFormatter to serialize the JSON to PDX, which I suspect Spring XD is doing similarly under-the-hood. In fact, Spring XD uses Spring Data GemFire and is most likely using the JSON Region Auto Proxy support. That is exactly what SDG's JSONRegionAdvice object does (see here).
Anyway, I have an inquiry out to the rest of the GemFire engineering team. There are also things that could be done in Spring Data GemFire to ensure the PDX data is converted, such as making use of the MappingPdxSerializer directly to convert the data automatically on behalf of the caller if the data is indeed of type PdxInstance. Similar to how JSON Region Auto Proxying works, you could write AOP interceptor for the Orders Region to automagicaly convert PDX to an Order.
Though, I don't think any of this should be necessary as GemFire should be doing the right thing in this case. Sorry I don't have a better answer right now. Let's see what I find out.
Cheers and stay tuned!
See subsequent post for test code.
I want my response to include this:
"keyMaps":{
"href":"http://localhost/api/keyMaps{/keyMapId}",
"templated":true
}
That's easy enough to achieve:
add(new Link("http://localhost/api/keyMaps{/keyMapId}", "keyMaps"));
But, of course, I'd rather use the ControllerLinkBuilder, like this:
add(linkTo(methodOn(KeyMapController.class).getKeyMap("{keyMapId}")).withRel("keyMaps"));
The problem is that by the time the variable "{keyMapId}" reaches the UriTemplate constructor, it's been included in an encoded URL:
http://localhost/api/keyMaps/%7BkeyMapId%7D
So UriTemplate's constructor doesn't recognise it as containing a variable.
How can I persuade ControllerLinkBuilder that I want to use template variables?
It looks to me like the current state of Spring-HATEOAS doesn't allow this via the ControllerLinkBuilder (I'd very much like to be proven wrong), so I have implemented this myself using the following classes for templating query parameters:
public class TemplatedLinkBuilder {
private static final TemplatedLinkBuilderFactory FACTORY = new TemplatedLinkBuilderFactory();
public static final String ENCODED_LEFT_BRACE = "%7B";
public static final String ENCODED_RIGHT_BRACE = "%7D";
private UriComponentsBuilder uriComponentsBuilder;
TemplatedLinkBuilder(UriComponentsBuilder builder) {
uriComponentsBuilder = builder;
}
public static TemplatedLinkBuilder linkTo(Object invocationValue) {
return FACTORY.linkTo(invocationValue);
}
public static <T> T methodOn(Class<T> controller, Object... parameters) {
return DummyInvocationUtils.methodOn(controller, parameters);
}
public Link withRel(String rel) {
return new Link(replaceTemplateMarkers(uriComponentsBuilder.build().toString()), rel);
}
public Link withSelfRel() {
return withRel(Link.REL_SELF);
}
private String replaceTemplateMarkers(String encodedUri) {
return encodedUri.replaceAll(ENCODED_LEFT_BRACE, "{").replaceAll(ENCODED_RIGHT_BRACE, "}");
}
}
and
public class TemplatedLinkBuilderFactory {
private final ControllerLinkBuilderFactory controllerLinkBuilderFactory;
public TemplatedLinkBuilderFactory() {
this.controllerLinkBuilderFactory = new ControllerLinkBuilderFactory();
}
public TemplatedLinkBuilder linkTo(Object invocationValue) {
ControllerLinkBuilder controllerLinkBuilder = controllerLinkBuilderFactory.linkTo(invocationValue);
UriComponentsBuilder uriComponentsBuilder = controllerLinkBuilder.toUriComponentsBuilder();
Assert.isInstanceOf(DummyInvocationUtils.LastInvocationAware.class, invocationValue);
DummyInvocationUtils.LastInvocationAware invocations = (DummyInvocationUtils.LastInvocationAware) invocationValue;
DummyInvocationUtils.MethodInvocation invocation = invocations.getLastInvocation();
Object[] arguments = invocation.getArguments();
MethodParameters parameters = new MethodParameters(invocation.getMethod());
for (MethodParameter requestParameter : parameters.getParametersWith(RequestParam.class)) {
Object value = arguments[requestParameter.getParameterIndex()];
if (value == null) {
uriComponentsBuilder.queryParam(requestParameter.getParameterName(), "{" + requestParameter.getParameterName() + "}");
}
}
return new TemplatedLinkBuilder(uriComponentsBuilder);
}
}
Which embeds the normal ControllerLinkBuilder and then uses similar logic to parse for #RequestParam annotated parameters that are null and add these on to the query parameters. Also, our client resuses these templated URIs to perform further requests to the server. To achieve this and not need to worry about stripping out the unused templated params, I have to perform the reverse operation (swapping {params} with null), which I'm doing using a custom Spring RequestParamMethodArgumentResolver as follows
public class TemplatedRequestParamResolver extends RequestParamMethodArgumentResolver {
public TemplatedRequestParamResolver() {
super(false);
}
#Override
protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest webRequest) throws Exception {
Object value = super.resolveName(name, parameter, webRequest);
if (value instanceof Object[]) {
Object[] valueAsCollection = (Object[])value;
List<Object> resultList = new LinkedList<Object>();
for (Object collectionEntry : valueAsCollection) {
if (nullifyTemplatedValue(collectionEntry) != null) {
resultList.add(collectionEntry);
}
}
if (resultList.isEmpty()) {
value = null;
} else {
value = resultList.toArray();
}
} else{
value = nullifyTemplatedValue(value);
}
return value;
}
private Object nullifyTemplatedValue(Object value) {
if (value != null && value.toString().startsWith("{") && value.toString().endsWith("}")) {
value = null;
}
return value;
}
}
Also this needs to replace the existing RequestParamMethodArgumentResolver which I do with:
#Configuration
public class ConfigureTemplatedRequestParamResolver {
private #Autowired RequestMappingHandlerAdapter adapter;
#PostConstruct
public void replaceArgumentMethodHandlers() {
List<HandlerMethodArgumentResolver> argumentResolvers = new ArrayList<HandlerMethodArgumentResolver>(adapter.getArgumentResolvers());
for (int cursor = 0; cursor < argumentResolvers.size(); ++cursor) {
HandlerMethodArgumentResolver handlerMethodArgumentResolver = argumentResolvers.get(cursor);
if (handlerMethodArgumentResolver instanceof RequestParamMethodArgumentResolver) {
argumentResolvers.remove(cursor);
argumentResolvers.add(cursor, new TemplatedRequestParamResolver());
break;
}
}
adapter.setArgumentResolvers(argumentResolvers);
}
}
Unfortunately, although { and } are valid characters in a templated URI, they are not valid in a URI, which may be a problem for your client code depending on how strict it is. I'd much prefer a neater solution built into Spring-HATEOAS!
With latest versions of spring-hateoas you can do the following:
UriComponents uriComponents = UriComponentsBuilder.fromUri(linkBuilder.toUri()).build();
UriTemplate template = new UriTemplate(uriComponents.toUriString())
.with("keyMapId", TemplateVariable.SEGMENT);
will give you: http://localhost:8080/bla{/keyMapId}",
Starting with this commit:
https://github.com/spring-projects/spring-hateoas/commit/2daf8aabfb78b6767bf27ac3e473832c872302c7
You can now pass null where path variable is expected. It works for me, without workarounds.
resource.add(linkTo(methodOn(UsersController.class).someMethod(null)).withRel("someMethod"));
And the result:
"someMethod": {
"href": "http://localhost:8080/api/v1/users/{userId}",
"templated": true
},
Also check related issues: https://github.com/spring-projects/spring-hateoas/issues/545
We've run into the same problem. General workaround is we have our own LinkBuilder class with a bunch of static helpers. Templated ones look like this:
public static Link linkToSubcategoriesTemplated(String categoryId){
return new Link(
new UriTemplate(
linkTo(methodOn(CategoryController.class).subcategories(null, null, categoryId))
.toUriComponentsBuilder().build().toUriString(),
// register it as variable
getBaseTemplateVariables()
),
REL_SUBCATEGORIES
);
}
private static TemplateVariables getBaseTemplateVariables() {
return new TemplateVariables(
new TemplateVariable("page", TemplateVariable.VariableType.REQUEST_PARAM),
new TemplateVariable("sort", TemplateVariable.VariableType.REQUEST_PARAM),
new TemplateVariable("size", TemplateVariable.VariableType.REQUEST_PARAM)
);
}
This is for exposing the parameters of a controller response of a PagedResource.
then in the controllers we call this an append a withRel as needed.
According to this issue comment, this will be addressed in an upcoming release of spring-hateoas.
For now, there's a drop-in replacement for ControllerLinkBuilder available from de.escalon.hypermedia:spring-hateoas-ext in Maven Central.
I can now do this:
import static de.escalon.hypermedia.spring.AffordanceBuilder.*
...
add(linkTo(methodOn(KeyMapController.class).getKeyMap(null)).withRel("keyMaps"));
I pass in null as the parameter value to indicate I want to use a template variable. The name of the variable is automatically pulled from the controller.
I needed to include a link with template variables in the root of a spring data rest application, to get access via traverson to an oauth2 token. This is working fine, maybe useful:
#Component
class RepositoryLinksResourceProcessor implements ResourceProcessor<RepositoryLinksResource> {
#Override
RepositoryLinksResource process(RepositoryLinksResource resource) {
UriTemplate uriTemplate = new UriTemplate(
ControllerLinkBuilder.
linkTo(
TokenEndpoint,
TokenEndpoint.getDeclaredMethod("postAccessToken", java.security.Principal, Map )).
toUriComponentsBuilder().
build().
toString(),
new TemplateVariables([
new TemplateVariable("username", TemplateVariable.VariableType.REQUEST_PARAM),
new TemplateVariable("password", TemplateVariable.VariableType.REQUEST_PARAM),
new TemplateVariable("clientId", TemplateVariable.VariableType.REQUEST_PARAM),
new TemplateVariable("clientSecret", TemplateVariable.VariableType.REQUEST_PARAM)
])
)
resource.add(
new Link( uriTemplate,
"token"
)
)
return resource
}
}
Based on the previous comments I have implemented a generic helper method (against spring-hateoas-0.20.0) as a "temporary" workaround. The implementation does consider only RequestParameters and is far from being optimized or well tested. It might come handy to some other poor soul traveling down the same rabbit hole though:
public static Link getTemplatedLink(final Method m, final String rel) {
DefaultParameterNameDiscoverer disco = new DefaultParameterNameDiscoverer();
ControllerLinkBuilder builder = ControllerLinkBuilder.linkTo(m.getDeclaringClass(), m);
UriTemplate uriTemplate = new UriTemplate(UriComponentsBuilder.fromUri(builder.toUri()).build().toUriString());
Annotation[][] parameterAnnotations = m.getParameterAnnotations();
int param = 0;
for (Annotation[] parameterAnnotation : parameterAnnotations) {
for (Annotation annotation : parameterAnnotation) {
if (annotation.annotationType().equals(RequestParam.class)) {
RequestParam rpa = (RequestParam) annotation;
String parameterName = rpa.name();
if (StringUtils.isEmpty(parameterName)) parameterName = disco.getParameterNames(m)[param];
uriTemplate = uriTemplate.with(parameterName, TemplateVariable.VariableType.REQUEST_PARAM);
}
}
param++;
}
return new Link(uriTemplate, rel);
}