Is there a way to configure the default Message<T> headers when the message is generated from the method return value:
#Publisher(channel = "theChannelname")
public MyObject someMethod(Object param) {
...
return myObject;
}
or
#SendTo("theChannelname")
public MyObject someMethod(Object param) {
...
return myObject;
}
In the examples above the Message<MyObject> will be automatically generated.
So, how can I control the default message generation?
Not really - the assumption is that if you return a payload then you don't care much about the headers. You can have the method return a Message and add your own headers there.
You can do that via #Header annotation for the method arguments:
#Publisher(channel="testChannel")
public String defaultPayload(String fname, #Header("last") String lname) {
return fname + " " + lname;
}
http://docs.spring.io/spring-integration/reference/html/message-publishing.html#publisher-annotation
Related
I'm trying to use Moshi with GraalVM's native-image, and trying to get the reflection to work.
I have my class:
public class SimpleJson {
private String message;
public SimpleJson(String message) { this.message = message; }
public String getMessage() { return message; }
public void setMessage(String message) { this.message = message; }
}
and code
var simpleJsonJsonAdapter = moshi.adapter(SimpleJson.class);
var simpleJsonString = "{\"message\": \"hello there\"}";
var simpleJsonObj = simpleJsonJsonAdapter.fromJson(simpleJsonString);
var simpleJsonStringBack = simpleJsonJsonAdapter.toJson(simpleJsonObj);
System.out.println("Converting: " + simpleJsonString);
System.out.println("Simple json has message: " + simpleJsonObj.getMessage());
System.out.println("Simple message full json coming back is: " + simpleJsonStringBack);
which prints:
Converting: {"message": "hello there"}
Simple json has message: null
Simple message full json coming back is: {}
and this only works (by avoiding an exception with SimpleJson is instantiated reflectively but was never registered) with the following chunk of code, to get everything registered ready for reflection:
#AutomaticFeature
public class RuntimeReflectionRegistrationFeature implements Feature {
#Override
public void beforeAnalysis(BeforeAnalysisAccess access) {
try {
// Enable the moshi adapters
var moshiPkgs = "com.squareup.moshi";
// Standard shared models
var pkgs = "my.models";
// Register moshi
new ClassGraph()
.enableClassInfo()
.acceptPackages(moshiPkgs)
.scan()
.getSubclasses(JsonAdapter.class.getName())
.forEach(
classInfo -> {
System.out.println("Building moshi adapter class info for " + classInfo);
registerMoshiAdapter(classInfo.loadClass());
});
// Register everything we've got
new ClassGraph()
.enableClassInfo() // Scan classes, methods, fields, annotations
.acceptPackages(pkgs) // Scan package(s) and subpackages
.scan()
.getAllClasses()
.forEach(
classInfo -> {
System.out.println("Building class info for " + classInfo);
registerGeneralClass(classInfo.loadClass());
});
} catch (Exception e) {
e.printStackTrace();
throw e;
}
}
private void registerMoshiAdapter(Class<?> classInfo) {
try {
RuntimeReflection.register(classInfo);
Arrays.stream(classInfo.getMethods()).forEach(RuntimeReflection::register);
ParameterizedType superclass = (ParameterizedType) classInfo.getGenericSuperclass();
// extends JsonAdapter<X>()
var valueType = Arrays.stream(superclass.getActualTypeArguments()).findFirst();
if (valueType.isPresent() && valueType.get() instanceof Class) {
Arrays.stream(((Class<?>) valueType.get()).getConstructors())
.forEach(RuntimeReflection::register);
}
RuntimeReflection.register(classInfo.getConstructor(Moshi.class));
} catch (RuntimeException | NoSuchMethodException name) {
// expected
}
}
private void registerGeneralClass(Class<?> classInfo) {
try {
RuntimeReflection.register(classInfo);
Arrays.stream(classInfo.getDeclaredMethods()).forEach(RuntimeReflection::register);
Arrays.stream(classInfo.getDeclaredConstructors()).forEach(RuntimeReflection::register);
} catch (RuntimeException name) {
// expected
}
}
}
(inspired by this issue, although I believe that's trying to address MoshiAdapters generated which is a Kotlin only thing).
So, Java doesn't complain about reflection (which it was previously trying to do, hence the error message mentioned), but Moshi isn't actually doing anything.
Does anyone have any suggestions on how to work around this?
Note, I did try the manual reflect-config.json approach with
[
{
"allDeclaredClasses": true,
"queryAllDeclaredConstructors": true,
"queryAllPublicConstructors": true,
"name": "my.models.SimpleJson",
"queryAllDeclaredMethods": true,
"queryAllPublicMethods": true,
"allPublicClasses": true
}
}
but this resulted in error around Runtime reflection is not supported for... - also not good!
The solution was simple in the end... the registration just needed
Arrays.stream(classInfo.getDeclaredFields()).forEach(RuntimeReflection::register);
adding.
This is my REST API:
#RequestMapping(value="/test1")
public String test1(#RequestBody TestPOJO tpj) {
if(tpj instanceof TestPOJO) {
System.out.println("Correct data format passed ");
}
return "working1";
}
This is structure of TestPOJO:
public class TestPOJO {
private String x;
private String y;
public String getX() {
return x;
}
public void setX(String x) {
this.x = x;
}
public String getY() {
return y;
}
public void setY(String y) {
this.y = y;
}
}
In POSTMAN client I am passing this requestbody to this API:
{
"sd":"u",
"egergdrg":34
}
Its printing "Correct data format passed ".Why this input structure is taken as a instance of "TestPOJO". I am passing completely different property inside the body even with different type of data. Isn't it supposed to give 400 Bad Request error ? Why its running successfully? How can I validate all the incoming request body is having proper structure similar to input parameter and if not return 400 error?
FYI Dependency added in pom.xml are "spring-boot-starter-web", "spring-boot-starter-test", "spring-boot-devtools".
You can validate your request body. Just annotate your reqúest body like this #Valid #RequestBody TestPOJO tpj then in your POJO Class, add e.g. following annotations to the fields:
#Size(min=5, max=5)
private String x;
which would actually check the length of the String x.
You can use more annotations, relying in the javax.annotation package.
Keep in minde that you need an annotation processor to make it work, e.g. hibernate-validator-annotation-processor
You can refer to this tutorial - Validating Form Input on Spring official website.
I modified your source as follows and tested it with Postman, now it will return 400 (Bad Request). And I don't think it should return 401 for wrong input data.
Your TestPOJO:
public class TestPOJO {
#NotNull
private String x;
#NotNull
private String y;
public String getX() {
return x;
}
public void setX(String x) {
this.x = x;
}
public String getY() {
return y;
}
public void setY(String y) {
this.y = y;
}
}
Your REST API:
#RequestMapping(value="/test1")
public String test1(#Valid #RequestBody TestPOJO tpj) {
if(tpj instanceof TestPOJO) {
System.out.println("Correct data format passed ");
}
return "working1";
}
BTW, once you add the dependency of spring-boot-starter-web into your pom file, the hibernate-validator will be added automatically.
this is because of the updates on the latest springboot version regarding the object mapper FailOnUnknownProperties. if you add this bean to your configuration, you will get 400 as expected
#Bean
public Jackson2ObjectMapperBuilder mapperBuilder() {
return new Jackson2ObjectMapperBuilder().failOnUnknownProperties(true);
}
I am working with Spring-websocket and I have the following problem:
I am trying to put a placeholder inside a #MessageMapping annotation in order to get the url from properties. It works with #RequestMapping but not with #MessageMapping.
If I use this placeholder, the URL is null. Any idea or suggestion?
Example:
#RequestMapping(value= "${myProperty}")
#MessageMapping("${myProperty}")
Rossen Stoyanchev added placeholder support for #MessageMapping and #SubscribeMapping methods.
See Jira issue: https://jira.spring.io/browse/SPR-13271
Spring allows you to use property placeholders in #RequestMapping, but not in #MessageMapping. This is 'cause the MessageHandler. So, we need to override the default MessageHandler to do this.
WebSocketAnnotationMethodMessageHandler does not support placeholders and you need add this support yourself.
For simplicity I just created another WebSocketAnnotationMethodMessageHandler class in my project at the same package of the original, org.springframework.web.socket.messaging, and override getMappingForMethod method from SimpAnnotationMethodMessageHandler with same content, changing only how SimpMessageMappingInfo is contructed using this with this methods (private in WebSocketAnnotationMethodMessageHandler):
private SimpMessageMappingInfo createMessageMappingCondition(final MessageMapping annotation) {
return new SimpMessageMappingInfo(SimpMessageTypeMessageCondition.MESSAGE, new DestinationPatternsMessageCondition(
this.resolveAnnotationValues(annotation.value()), this.getPathMatcher()));
}
private SimpMessageMappingInfo createSubscribeCondition(final SubscribeMapping annotation) {
final SimpMessageTypeMessageCondition messageTypeMessageCondition = SimpMessageTypeMessageCondition.SUBSCRIBE;
return new SimpMessageMappingInfo(messageTypeMessageCondition, new DestinationPatternsMessageCondition(
this.resolveAnnotationValues(annotation.value()), this.getPathMatcher()));
}
These methods now will resolve value considering properties (calling resolveAnnotationValues method), so we need use something like this:
private String[] resolveAnnotationValues(final String[] destinationNames) {
final int length = destinationNames.length;
final String[] result = new String[length];
for (int i = 0; i < length; i++) {
result[i] = this.resolveAnnotationValue(destinationNames[i]);
}
return result;
}
private String resolveAnnotationValue(final String name) {
if (!(this.getApplicationContext() instanceof ConfigurableApplicationContext)) {
return name;
}
final ConfigurableApplicationContext applicationContext = (ConfigurableApplicationContext) this.getApplicationContext();
final ConfigurableBeanFactory configurableBeanFactory = applicationContext.getBeanFactory();
final String placeholdersResolved = configurableBeanFactory.resolveEmbeddedValue(name);
final BeanExpressionResolver exprResolver = configurableBeanFactory.getBeanExpressionResolver();
if (exprResolver == null) {
return name;
}
final Object result = exprResolver.evaluate(placeholdersResolved, new BeanExpressionContext(configurableBeanFactory, null));
return result != null ? result.toString() : name;
}
You still need to define a PropertySourcesPlaceholderConfigurer bean in your configuration.
If you are using XML based configuration, include something like this:
<context:property-placeholder location="classpath:/META-INF/spring/url-mapping-config.properties" />
If you are using Java based configuration, you can try in this way:
#Configuration
#PropertySources(value = #PropertySource("classpath:/META-INF/spring/url-mapping-config.properties"))
public class URLMappingConfig {
#Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
}
Obs.: in this case, url-mapping-config.properties file are in a gradle/maven project in src\main\resources\META-INF\spring folder and content look like this:
myPropertyWS=urlvaluews
This is my sample controller:
#Controller
public class WebSocketController {
#SendTo("/topic/test")
#MessageMapping("${myPropertyWS}")
public String test() throws Exception {
Thread.sleep(4000); // simulated delay
return "OK";
}
}
With default MessageHandler startup log will print something like this:
INFO: Mapped "{[/${myPropertyWS}],messageType=[MESSAGE]}" onto public java.lang.String com.brunocesar.controller.WebSocketController.test() throws java.lang.Exception
And with our MessageHandler now print this:
INFO: Mapped "{[/urlvaluews],messageType=[MESSAGE]}" onto public java.lang.String com.brunocesar.controller.WebSocketController.test() throws java.lang.Exception
See in this gist the full WebSocketAnnotationMethodMessageHandler implementation.
EDIT: this solution resolves the problem for versions before 4.2 GA. For more information, see this jira.
Update :
Now I understood what you mean, but I think that is not possible(yet).
Documentation does not mention anything related to Path mapping URIs.
Old answer
Use
#MessageMapping("/handler/{myProperty}")
instead of
#MessageMapping("/handler/${myProperty}")
And use it like this:
#MessageMapping("/myHandler/{username}")
public void handleTextMessage(#DestinationVariable String username,Message message) {
//do something
}
#MessageMapping("/chat/{roomId}")
public Message handleMessages(#DestinationVariable("roomId") String roomId, #Payload Message message, Traveler traveler) throws Exception {
System.out.println("Message received for room: " + roomId);
System.out.println("User: " + traveler.toString());
// store message in database
message.setAuthor(traveler);
message.setChatRoomId(Integer.parseInt(roomId));
int id = MessageRepository.getInstance().save(message);
message.setId(id);
return message;
}
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);
}
Suppose I have a Website that is used in normal mode (browser) and in some other mode, like a MobileView mode (inside a mobile app). For each Controller I create, there might be correspondent controller for MobileView, processing the same url.
The easiest solution is to create ifs in all the Controllers that have MobileView logic. Another solution would be to use a correspondent url for MobileView (similar to the normal url) and two separate Controllers (possible where one extends from another; or use some other way to recycle common code)
But, a more elegant solution would be to have some extra annotations, like #SupportsMobileView (to mark a controller, and tell the app that this will have a correspondent MobileView Controller) and #MobileViewController (to mark a second controller, and tell the app that this controller needs to run immediately after the initial controller marked with #SupportsMobileView). The link between a normal controller and a MobileView controller would be through the url they process (defined with #RequestMapping).
Is it possible to extend Spring MVC (A)? Where to inject new annotation scanners (B) and annotation handlers / component handlers (C)? How should the MobileView controller be executed (D) (right now I am thinking that it could be executed through AOP, where the new handler of my new controller type programatically creates a Join-Point on the corresponding normal controller)
Note that I did not mention how this MobileView mode is triggered and detected. Let's just say that there a Session boolean variable (flag) for that.
Critics on any points (A), (B), (C) or (D) are welcomed, as well as technical hints and alternative solution to any point or the whole solution.
HandlerInterceptor can be used to intercept the RequestMapping handling. This is a simple example how to configure and implement one.
You can check for your session variable and will have a bunch of methods that will allow you to do custom processing or just exchange the view from the normal controller handling with your mobile view.
Ok, warnings:
this is only a proof of concept of what I understood must be done so:
+#MobileViewEnable and #MobileView annotated (and related) methods need to stay in the same controller
+there's no check for the httpAction used
+the two methods must have the same signature
+mobileView annotation value and requestMapping annotation value must be equals and uniques
+the logic inside callYourLogic(..) defines which method is going to be called, at the moment there's a very simple logic that check if exist the parameter ("mobile") in the request, just to test
+this code is not intended to be used as is (at all)
+don't know if it works at all outside my pc (joke :D, ehm..)
SO:
Annotations:
#Retention(RetentionPolicy.RUNTIME)
public #interface MobileView {
String value() default "";
}
#Retention(RetentionPolicy.RUNTIME)
public #interface MobileViewEnable {
}
ExampleController:
#Controller
public class MainController extends BaseController {
private final static Logger logger = LoggerFactory.getLogger(MainController.class);
private final static String PROVA_ROUTE = "prova";
#MobileViewEnable
#RequestMapping(PROVA_ROUTE)
public String prova() {
logger.debug("inside prova!!!");
return "provaview";
}
#MobileView(PROVA_ROUTE)
public String prova2() {
logger.debug("inside prova2!!!");
return "prova2view";
}
}
Aspect definition:
<bean id="viewAspect" class="xxx.yyy.ViewAspect" />
<aop:config>
<aop:pointcut expression="#annotation(xxx.yyy.MobileViewEnable)" id="viewAspectPointcut" />
<aop:aspect ref="viewAspect" order="1">
<aop:around method="around" pointcut-ref="viewAspectPointcut" arg-names="viewAspectPointcut"/>
</aop:aspect>
</aop:config>
Aspect implementation:
public class ViewAspect implements BeforeAdvice, ApplicationContextAware {
private final static Logger logger = LoggerFactory.getLogger(ViewAspect.class);
private ApplicationContext applicationContext;
public Object around(ProceedingJoinPoint joinPoint) {
Method mobileViewAnnotatedMethod = null;
HttpServletRequest request = getCurrentHttpRequest();
String controllerName = getSimpleClassNameWithFirstLetterLowercase(joinPoint);
Object[] interceptedMethodArgs = getInterceptedMethodArgs(joinPoint);
String methodName = getCurrentMethodName(joinPoint);
Method[] methods = getAllControllerMethods(joinPoint);
Method interceptedMethod = getInterceptedMethod(methods, methodName);
String interceptedMethodRoute = getRouteFromInterceptedMethod(interceptedMethod);
if (callYourLogic(request)) {
mobileViewAnnotatedMethod = getMobileViewAnnotatedMethodWithRouteName(methods, interceptedMethodRoute);
if (mobileViewAnnotatedMethod != null)
return invokeMethod(mobileViewAnnotatedMethod, interceptedMethodArgs, controllerName);
}
return continueInterceptedMethodExecution(joinPoint, interceptedMethodArgs);
}
private Object continueInterceptedMethodExecution(ProceedingJoinPoint joinPoint, Object[] interceptedMethodArgs) {
try {
return joinPoint.proceed(interceptedMethodArgs);
} catch (Throwable e) {
logger.error("unable to proceed with intercepted method call: " + e);
}
return null;
}
private Object[] getInterceptedMethodArgs(JoinPoint joinPoint) {
return joinPoint.getArgs();
}
private boolean callYourLogic(HttpServletRequest request) {
// INSERT HERE YOUR CUSTOM LOGIC (e.g.: is the server accessed from a mobile device?)
// THIS IS A STUPID LOGIC USED ONLY FOR EXAMPLE
return request.getParameter("mobile")!= null;
}
private HttpServletRequest getCurrentHttpRequest() {
return ((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest();
}
private String invokeMethod(Method method, Object[] methodArgs, String className) {
if (method != null) {
try {
Object classInstance = getInstanceOfClass(method, className);
return (String) method.invoke(classInstance, methodArgs);
} catch (Exception e) {
logger.error("unable to invoke method" + method + " - " + e);
}
}
return null;
}
private Object getInstanceOfClass(Method method, String className) {
return applicationContext.getBean(className);
}
private Method getMobileViewAnnotatedMethodWithRouteName(Method[] methods, String routeName) {
for (Method m : methods) {
MobileView mobileViewAnnotation = m.getAnnotation(MobileView.class);
if (mobileViewAnnotation != null && mobileViewAnnotation.value().equals(routeName))
return m;
}
return null;
}
private String getRouteFromInterceptedMethod(Method method) {
RequestMapping requestMappingAnnotation = method.getAnnotation(RequestMapping.class);
if (requestMappingAnnotation != null)
return requestMappingAnnotation.value()[0];
return null;
}
private String getCurrentMethodName(JoinPoint joinPoint) {
return joinPoint.getSignature().getName();
}
private Method[] getAllControllerMethods(JoinPoint joinPoint) {
return joinPoint.getThis().getClass().getSuperclass().getMethods();
}
private String getSimpleClassNameWithFirstLetterLowercase(JoinPoint joinPoint) {
String simpleClassName = joinPoint.getThis().getClass().getSuperclass().getSimpleName();
return setFirstLetterLowercase(simpleClassName);
}
private String setFirstLetterLowercase(String simpleClassName) {
String firstLetterOfTheString = simpleClassName.substring(0, 1).toLowerCase();
String restOfTheString = simpleClassName.substring(1);
return firstLetterOfTheString + restOfTheString;
}
private Method getInterceptedMethod(Method[] methods, String lookingForMethodName) {
for (Method m : methods)
if (m.getName().equals(lookingForMethodName))
return m;
return null;
}
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}
}