Database event handling by spring - spring

I want to handle database events with spring. spring has event handling mechanism and I have defined some custom event handlers in spring. for example if an employee gets inactivate in system so certain sets of activity are required to perform so is there any way in which spring custom event listners can be fired. I am using spring with hibernate.
I suspect if there could be a way in hibernate to achieve this but i want to handle it spring. Thanks in advance

If I understand your question correctly, you need to know a way to intercept hibernate entity change event and trigger an event which can be handled by Spring. You can always intercept events in hibernate i.e., inspect and/or change property values of hibernate entity elements using Interceptor. For example, Employee entity has status(say String) field, you can detect change(say, changed from active to inactive) to this field and perform some action before change can be persisted to database. Changes to any collection present in this entity can be intercepted as well. For brevity I am taking up only field change.
Define a listener interface FieldChangeListener for field change tracking as:
public interface FieldChangeListener<T>{
/**
* Defining generically so that it can be implemented by any entity on which field change needs to be observed.
* #param propertyName - the property name on the entity
* #param entity - the entity object
* #param previousState - the old value
* #param currentState - the new value
* */
void onChange(Object[] previousState, Object[] currentState, String[] propertyName, Type[] types, Object entity);
}
In order to use said Interceptor, we need to create a class that extends EmptyInterceptor:
public class FieldChangeInterceptor extends EmptyInterceptor {
private Map<Class, FieldChangeListener<?>> listeners;
public void setListeners(Map<Class, FieldChangeListener<?>> listeners) {
this.listeners = listeners;
}
#Override
public boolean onFlushDirty(Object entity, Serializable id, Object[] currentState, Object[] previousState, String[] propertyNames, Type[] types) {
FieldChangeListener<?> listener = listeners.get(entity.getClass());
boolean report = false;
// Only check for changes if an entity-specific listener was registered.
if (listener != null) {
listener.onChange(previousState, currentState, propertyNames, types, entity);
report = true;
}
return report;
}
}
Define the interceptor and listener(s) in your context xml as:
<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
...
</bean>
<bean id="fieldInterceptor" class="package.FieldChangeInterceptor">
<property name="listeners">
<util:map id="listeners" map-class="java.util.HashMap">
<entry>
<key><value>package.Employee</value></key><ref bean="employeeListener"/>
</entry>
</util:map>
</property>
</bean>
<bean id="employeeListener" class="package.listener.EmployeeListener"/>
EmployeeListener class is:
public class EmployeeListener implements FieldChangeListener<Employee>, ApplicationEventPublisherAware{
private ApplicationEventPublisher publisher;
public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {
this.publisher = publisher;
}
#Override
public void onChange(Object[] previousState, Object[] currentState, String[] propertyName, Type[] types, Object obj) {
log.info("Enter onChange()...");
Employee employee = (Employee)obj;
boolean isChange = false;
for (int i = 0; i < currentState.length; i++) {
if (currentState[i] == null) {
if (previousState[i] != null){
isChange = true;
}else{
isChange = false;
}
} else if (!currentState[i].equals(previousState[i])) {
isChange = true;
}
if (isChange) {
//check for status property of Employee
if(propertyName[i].equals("status")){
//Do your activity here - maybe you want to publish application event using eventService.
//Define event.
publisher.publishEvent(event);
}
report = false;
}
}
log.info("Exit onChange()...");
}
To publish a custom ApplicationEvent, call the publishEvent() method on an ApplicationEventPublisher. For more details on event publishing, please check
Section 5.14.2 Standard and Custom Events here.

Related

Read Application Object from GemFire using Spring Data GemFire. Data stored using SpringXD's gemfire-json-server

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.

How can I log method expressions of JSF ajax requests

I have figured out how to log when a request is an ajax request and which page it is from, in a filter.
What I would really like to do is log what the ajax request is actually for. Such as the name of the method being called by the ajax (eg "findAddress" in this call:<p:ajax process="contactDetails" update="#form" listener="#{aboutYouController.findAddress}" .... )
How can I do this? My app has many ajax requests and I want to log which are being triggered.
public class TrackingFilter implements Filter {
private static Logger LOG = Logger.getLogger(TrackingFilter.class);
#Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
HttpServletRequest req = (HttpServletRequest) request;
String pageHit = req.getRequestURI().substring(req.getContextPath().length()+1).replace(".xhtml", "");
if(!pageHit.contains("javax.faces.resource")){ // if is a url we want to log
if ("partial/ajax".equals(req.getHeader("Faces-Request"))) {
LOG.trace("ajax on URI: " + req.getRequestURI());
}
What I would really like to do is log what the ajax request is actually for. Such as the name of the method being called by the ajax (eg "findAddress" in this call:<p:ajax process="contactDetails" update="#form" listener="#{aboutYouController.findAddress}" ....)
This information is only available in the JSF component tree. The JSF component tree is only available after view build time. A view is only built when the request has been served by FacesServlet. Thus, a servlet filter is way too early as it runs before any servlet.
You'd better run the code after the restore view phase of a postback. The JSF component tree is guaranteed to be available during that moment. You can use FacesContext#isPostback() to check if the current request is a postback. You can use PartialViewContext#isAjaxRequest() to check if the current request is an ajax request. You can use the predefined javax.faces.source request parameter to obtain the client ID of the source component of the ajax request. You can use the predefined javax.faces.behavior.event request parameter to obtain the ajax event name (e.g. change, click, action, etc).
Obtaining the associated behavior listeners is in turn a story apart. This is easy on ActionSource2 components (e.g. <h|p:commandButton action="#{...}">) as the MethodExpression is just available by ActionSource2#getActionExpression(). However, this isn't easy on BehaviorBase taghandlers (e.g. <f|p:ajax listener="#{...}">) as this API doesn't have any method like getBehaviorListeners(). There are only methods to add and remove them, but not to obtain a list of them. So some nasty reflection trickery is necessary to access the private field with those listeners whose name is JSF implementation specific. In Mojarra it's listeners and in MyFaces it's _behaviorListeners. Both are fortunately assignable from List and it's the only field of that type, so we could just check for that. Once having hand of the BehaviorListener instance, then you still need to do another reflection trickery to obtain the MethodExpression field of that instance. Yuck.
All in all, here's how the trickery look like in flavor of a PhaseListener listening on afterPhase of RESTORE_VIEW:
public class AjaxActionLoggerPhaseListener implements PhaseListener {
#Override
public PhaseId getPhaseId() {
return PhaseId.RESTORE_VIEW;
}
#Override
public void beforePhase(PhaseEvent event) {
// NOOP.
}
#Override
public void afterPhase(PhaseEvent event) {
FacesContext context = event.getFacesContext();
if (!(context.isPostback() && context.getPartialViewContext().isAjaxRequest())) {
return; // Not an ajax postback.
}
Map<String, String> params = context.getExternalContext().getRequestParameterMap();
String sourceClientId = params.get("javax.faces.source");
String behaviorEvent = params.get("javax.faces.behavior.event");
UIComponent source = context.getViewRoot().findComponent(sourceClientId);
List<String> methodExpressions = new ArrayList<>();
if (source instanceof ClientBehaviorHolder && behaviorEvent != null) {
for (ClientBehavior behavior : ((ClientBehaviorHolder) source).getClientBehaviors().get(behaviorEvent)) {
List<BehaviorListener> listeners = getField(BehaviorBase.class, List.class, behavior);
if (listeners != null) {
for (BehaviorListener listener : listeners) {
MethodExpression methodExpression = getField(listener.getClass(), MethodExpression.class, listener);
if (methodExpression != null) {
methodExpressions.add(methodExpression.getExpressionString());
}
}
}
}
}
if (source instanceof ActionSource2) {
MethodExpression methodExpression = ((ActionSource2) source).getActionExpression();
if (methodExpression != null) {
methodExpressions.add(methodExpression.getExpressionString());
}
}
System.out.println(methodExpressions); // Do your thing with it.
}
private static <C, F> F getField(Class<? extends C> classType, Class<F> fieldType, C instance) {
try {
for (Field field : classType.getDeclaredFields()) {
if (field.getType().isAssignableFrom(fieldType)) {
field.setAccessible(true);
return (F) field.get(instance);
}
}
} catch (Exception e) {
// Handle?
}
return null;
}
}
In order to get it to run, register as below in faces-config.xml:
<lifecycle>
<phase-listener>com.example.AjaxActionLoggerPhaseListener</phase-listener>
</lifecycle>
Above is tested and compatible with Mojarra and PrimeFaces and theoretically also compatible with MyFaces.
Update: in case you're using JSF utility library OmniFaces, or are open to, since version 2.4 you can use the new Components#getCurrentActionSource() utility method to find out the current action source component and Components#getActionExpressionsAndListeners() to get a list of all action methods and listeners registered on a given component. This is also useable on regular (non-ajax) requests. With that, the above PhaseListener example can be reduced as below:
public class FacesActionLoggerPhaseListener implements PhaseListener {
#Override
public PhaseId getPhaseId() {
return PhaseId.PROCESS_VALIDATIONS;
}
#Override
public void beforePhase(PhaseEvent event) {
// NOOP.
}
#Override
public void afterPhase(PhaseEvent event) {
if (!event.getFacesContext().isPostback())) {
return;
}
UIComponent source = Components.getCurrentActionSource();
List<String> methodExpressions = Components.getActionExpressionsAndListeners(source);
System.out.println(methodExpressions); // Do your thing with it.
}
}

How do I validate my DWR #RemoteMethod input objects?

I’m using DWR 3.0.0-rc2 and Spring 3.1.1.RELEASE.  I was wondering if its possible to validate my #DataTransferObject input object using the Spring style “#Valid” (javax.validation.Valid) annotation.  My specific question is, if this is possible and I set up my remote call like so …
#RemoteMethod
#Override
public String myRemoteMethod(#Valid final MyDto request)
{
how do I test to see if the input object (request) is valid and then throw a corresponding set of errors back to the client?
Thanks, - Dave
This looks like a good case to apply some AOP. One way is to create a #Before aspect that inspects the called arguments to see if they are annotated with #Valid, and if so trigger the validation for that argument and treat the results.
The code of this aspect would look like this:
#Aspect
public class ValidatingAspect {
Validator validator;
public ValidatingAspect() {
Configuration<?> configuration = Validation.byDefaultProvider().configure();
ValidatorFactory factory = configuration.buildValidatorFactory();
this.validator = factory.getValidator();
}
#Before("execution(* com.yourpackage..*.*(..))")
public void validateBefore(JoinPoint jp) throws Throwable {
Object[] args = jp.getArgs();
MethodSignature ms = (MethodSignature) jp.getSignature();
Method m = ms.getMethod();
Annotation[][] parameterAnnotations = m.getParameterAnnotations();
for (int i = 0; i < parameterAnnotations.length; i++) {
Annotation[] annotations = parameterAnnotations[i];
for (Annotation annotation : annotations) {
if (annotation.annotationType() == Valid.class) {
Set<ConstraintViolation<T>> constraintViolations = validator.validate(jp.getArgs()[i]);
... handle validation results ...
}
}
}
}
}

Looking for a solution to extend Spring MVC with another Component/Annotation

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;
}
}

Custom property editors do not work for request parameters in Spring MVC?

I'm trying to create a multiaction web controller using Spring annotations. This controller will be responsible for adding and removing user profiles and preparing reference data for the jsp page.
#Controller
public class ManageProfilesController {
#InitBinder
public void initBinder(WebDataBinder binder) {
binder.registerCustomEditor(UserAccount.class,"account", new UserAccountPropertyEditor(userManager));
binder.registerCustomEditor(Profile.class, "profile", new ProfilePropertyEditor(profileManager));
logger.info("Editors registered");
}
#RequestMapping("remove")
public void up( #RequestParam("account") UserAccount account,
#RequestParam("profile") Profile profile) {
...
}
#RequestMapping("")
public ModelAndView defaultView(#RequestParam("account") UserAccount account) {
logger.info("Default view handling");
ModelAndView mav = new ModelAndView();
logger.info(account.getLogin());
mav.addObject("account", account);
mav.addObject("profiles", profileManager.getProfiles());
mav.setViewName(view);
return mav;
}
...
}
Here is the part of my webContext.xml file:
<context:component-scan base-package="ru.mirea.rea.webapp.controllers" />
<context:annotation-config/>
<bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
<property name="mappings">
<value>
...
/home/users/manageProfiles=users.manageProfilesController
</value>
</property>
</bean>
<bean id="users.manageProfilesController" class="ru.mirea.rea.webapp.controllers.users.ManageProfilesController">
<property name="view" value="home\users\manageProfiles"/>
</bean>
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
However, when i open the mapped url, i get exception:
java.lang.IllegalArgumentException: Cannot convert value of type [java.lang.String] to required type [ru.mirea.rea.model.UserAccount]: no matching editors or conversion strategy found
I use spring 2.5.6 and plan to move to the Spring 3.0 in some not very distant future. However, according to this JIRA https://jira.springsource.org/browse/SPR-4182 it should be possible already in spring 2.5.1.
The debug shows that the InitBinder method is correctly called.
What am i doing wrong?
Update:
public class UserAccountPropertyEditor extends PropertyEditorSupport {
static Logger logger = Logger.getLogger(UserAccountPropertyEditor.class);
public UserAccountPropertyEditor(IUserDAO dbUserManager) {
this.dbUserManager = dbUserManager;
}
private IUserDAO dbUserManager;
public String getAsText() {
UserAccount obj = (UserAccount) getValue();
if (null==obj) {
return "";
} else {
return obj.getId().toString();
}
}
public void setAsText(final String value) {
try {
Long id = Long.parseLong(value);
UserAccount acct = dbUserManager.getUserAccountById(id);
if (null!=acct) {
super.setValue(acct);
} else {
logger.error("Binding error. Cannot find userAccount with id ["+value+"]");
throw new IllegalArgumentException("Binding error. Cannot find userAccount with id ["+value+"]");
}
} catch (NumberFormatException e) {
logger.error("Binding error. Invalid id: " + value);
throw new IllegalArgumentException("Binding error. Invalid id: " + value);
}
}
}
There are no errors logged from UserAccountPropertyEditor.
I don't think you want to be specifying the field argument to WebDataBinder.registerCustomEditor(). This intended to work alongside form-backing objects, and you're not using that.
Try the simpler 2-arg method instead, and it should work:
binder.registerCustomEditor(UserAccount.class, new UserAccountPropertyEditor(userManager));
binder.registerCustomEditor(Profile.class, new ProfilePropertyEditor(profileManager));

Resources