Jersey Guice AOP

Jersey + Guice + AOP

Domenico Briganti
dometec@gmail.com

Chi sono?
@PerRequest
public class Presentation {

@GET
@Path("/JugMilano/People/DomenicoBriganti")
@Produces(MediaType.APPLICATION_JSON)
public Response getUserDetails() {

UserDetails userdet = new UserDetails();
userdet.setCompany("Eidon srl");
userdet.setEmail("dometec@gmail.com");
userdet.setLinkedin("http://www.linkedin.com/in/dometec");
userdet.setBlog("http://tipsaboutmywork.blogspot.com/");
...

return Response.ok(userdet).build();

}

JUG Milano – Meeting #48 2

Agenda
JAX-RS
Jersey con Guice/AOP

Demos:
Log delle richieste
Trim dei parametri Stringa in ingresso
Evitare chiamate identiche su un cluster
Transazioni
Login cookie


JAX-RS
Java API for RESTful Web Services
Release 1.1, JSR 311, 2009, JEE6 Full
Release futura 2.0, JSR 339, (EDR2 2012), JEE7
Package: javax.ws.rest
Implementazioni: Jersey (RI), Apache CXF,
RESTEasy, Apache Wink


Jersey
Open source, RI for JAX-RS

Jersey 1.x (1.13b1) implements JAX-RS 1.1

Jersey 2.x (mileston 3) implements JAX-RS 2

CDDL + GPL 1.1


Jersey Hello World
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.core.Response;

@Path("/hello")
public class HelloWorldService {

@GET
@Path("/{param}")
public Response getMsg(@PathParam("param") String msg) {

String output = "Echo: " + msg;
return Response.ok(output).build();

}

}


JAX-RS Annotation
Verbi HTTP: @GET, @POST, @PUT, @DELETE,
@OPTION, @HEAD

Identificazione risorse: @Path

Input: @PathParam, @QueryParam, @MatrixParam,
@HeaderParam, @CookieParam. @FormParam.
@DefaultValue. MultivaluedMap<String, String>

Content negotiation: @Produces, @Consume


JAX-RS Annotation e Facility
Ambiente: @Context (ServletConfig, ServletContext,
HttpServletRequest, HttpServletResponse,
SecurityContext, UriInfo, HttpHeaders)

Mapper, MessageBodyWriters,
MessageBodyReaders: @Provider

ResponseBuilder e UriBuilder


DEMO 0

“Esecuzione” della
slide di presentazione


Jersey-Guice integration
<listener>
<listener-class>org.example.demo.GuiceConfig</listener-class>
</listener>

<filter>
<filter-name>GuiceFilter</filter-name>
web.xml:
web.xml

<filter-class>com.google.inject.servlet.GuiceFilter</filter-class>
</filter>

<filter-mapping>
<filter-name>GuiceFilter</filter-name>
<url-pattern>/services/*</url-pattern>
<url-pattern>/application.wadl</url-pattern>
<url-pattern>/application.wadl/*</url-pattern>
</filter-mapping>

package org.example.demo;

public class GuiceConfig extends GuiceServletContextListener {

@Override
listener

protected Injector getInjector() {

return Guice.createInjector(new JerseyServletModule() {
@Override
protected void configureServlets() {

Map<String, String> params = new HashMap<String, String>();

params.put(PackagesResourceConfig.PROPERTY_PACKAGES, "org.example.demo");
params.put(ResourceConfig.FEATURE_TRACE, "true");
params.put(ResourceConfig.FEATURE_TRACE_PER_REQUEST, "true");
...


Demo 1

Log delle richieste


Demo 1 – Log delle richieste (interc.)
public class LogCall implements MethodInterceptor {

public Object invoke(MethodInvocation invocation) throws Throwable {

Logger logger = LoggerFactory.getLogger(invocation.getThis().getClass());

String arg = Joiner.on(", ").useForNull("null").join(invocation.getArguments());
logger.debug("{} ({}).", invocation.getMethod().getName(), arg);

Object result = invocation.proceed();

logger.trace("Output: {}.", result);

return result;

}

}


Demo 1 – Log delle richieste (bind)

@Override


@Override


...

filter("/*").through(GuiceContainer.class, params);

install(new Module() {

public void configure(Binder binder) {

LogCall logCall = new LogCall();
TrimAndNullInterceptor trimAndNullableInterceptor = new TrimAndNullInterceptor();

bindInterceptor(
Matchers.annotatedWith(Path.class),
Matchers.annotatedWith(GET.class).or(Matchers.annotatedWith(POST.class))
.or(Matchers.annotatedWith(PUT.class)).or(Matchers.annotatedWith(DELETE.class)),
trimAndNullableInterceptor, logCall);


Demo 2 – Trim parametri (interc.)
public class TrimAndNullInterceptor implements MethodInterceptor {


for (int i = 0; i < invocation.getArguments().length; i++) {

if (invocation.getArguments()[i] != null &&
invocation.getArguments()[i] instanceof String) {

String sparam = (String) invocation.getArguments()[i];

String trim = sparam.trim();

if (trim.isEmpty())
invocation.getArguments()[i] = null;
else
invocation.getArguments()[i] = trim;
}

}

return invocation.proceed();

}
}


Demo 2 – Trim parametri (bind)

@Override


@Override


...




LogCall logCall = new LogCall();
TrimAndNullInterceptor trimAndNullableInterceptor = new TrimAndNullInterceptor();

bindInterceptor(
Matchers.annotatedWith(Path.class),
Matchers.annotatedWith(GET.class).or(Matchers.annotatedWith(POST.class))
.or(Matchers.annotatedWith(PUT.class)).or(Matchers.annotatedWith(DELETE.class)),
trimAndNullableInterceptor, logCall);


Evitare richieste duplicate
Problemi:
Ristrasmissioni
Doppi submit (anche Tripli...) da browser
Timeout lato client che scatena altre prove di richieste

Rimedi:
Hashtable con chiamate attualmente in corso
429 Too Many Requests (RFC 6585)
Infinispan con lock condiviso per sistemi cluster


Demo 3 – Richieste duplicate (uso)
@POST
@UniqueCallOnCluster
public Response getAccountBalance(@FormParam("fromuser")...

@POST
@UniqueCallOnCluster
public Response getAccountBalance(@KeyParameter
@FormParam("fromuser")...


Demo 3 – Richieste duplicate (Inter.)
public class UniqueCallOnClusterInterceptor implements MethodInterceptor {
...

String classname = invocation.getMethod().getDeclaringClass().getSimpleName();
String methodName = invocation.getMethod().getName();
String key = classname + "_" + methodName + "_" + extractParameterValue(invocation);

TransactionManager tm = keyCallOnClusterService.getTransactionManager();

tm.begin();
boolean success = keyCallOnClusterService.lock(key);

if (!success) {
logger.info("Non posso effettuare il lock sul cluster per la chiave {}.", key);
return Response.status(429).entity("Another call with same parameter is in progress.").build();
}

String runningServer = (String) keyCallOnClusterService.get(key);
if (runningServer != null) {
logger.info("Chiamata già in corso, server {}.", runningServer);
return Response.status(429).entity("Another call with same parameter is in progress.").build();
}

keyCallOnClusterService.put(key, "todo-hostname");
tm.commit();
...
return invocation.proceed();
...

keyCallOnClusterService.remove(key);

}


Demo 3 – Richieste duplicate (bind)

@Override


@Override


...




UniqueCallOnClusterInterceptor uniqueCallOnClusterInterceptor =
new UniqueCallOnClusterInterceptor();
requestInjection(uniqueCallOnClusterInterceptor);
bindInterceptor(Matchers.any(), Matchers.annotatedWith(UniqueCallOnCluster.class),
uniqueCallOnClusterInterceptor);


Transazioni con AOP


Demo 4 – Transazioni (uso)
package org.example.demo.controller;

@PerRequest
@Transactional
@Path("services/transactionalresource3")
public class TransactionalResource3Write extends AbstractTransactionalResource {

@Inject
public TransactionalResource3Write() {
}

@POST
@Produces("text/plain")
public String get() {

...



@PerRequest
@Transactional(TransactionType.ReadOnly)
public class TransactionalResource1ReadOnly extends AbstractTransactionalResource {

@Inject
public TransactionalResource1ReadOnly() {
}

@GET
@Produces("text/plain")
@SuppressWarnings("unchecked")
public String get() {

List<DatabaseLog> list = getSession().createCriteria(DatabaseLog.class).list();

if (list.size() == 0)
return "No record!";


@PerRequest
@Transactional(TransactionType.RequiredNew)
public class TransactionalResource5ReqNew extends AbstractTransactionalResource {

@Inject
public TransactionalResource5ReqNew() {
}

...


public abstract class AbstractTransactionalResource {
private Session session;

@NoTransactional
public void setSession(Session session) {
this.session = session; }

@NoTransactional
public Session getSession() {
return session; }

@Override
@NoTransactional
protected void finalize() throws Throwable {
super.finalize(); }

}

Demo 4 – Transazioni 1/2 (interc.)
public class TransactionInterceptor implements MethodInterceptor {

private final ThreadLocal<Stack<Session>> sessionThreadLocal;

...
Transactional transactional =
invocation.getMethod().getDeclaringClass().getAnnotation(Transactional.class);
...

Stack<Session> sessionStack = sessionThreadLocal.get();
Transaction transaction = null;
Session session = null;
if (!sessionStack.isEmpty())
session = sessionStack.peek();

if (session == null || transType.equals(TransactionType.RequiredNew)) {

boolean readonly = false;
readonly = transType.equals(TransactionType.ReadOnly);
session = hibernateSessionService.openSession(readonly);
transaction = session.getTransaction();
transaction.begin();
sessionStack.push(session);
}

Session oldSession = null;
AbstractTransactionalResource service = ((AbstractTransactionalResource)
invocation.getThis());
oldSession = service.getSession();
service.setSession(session);



Demo 4 – Transazioni 2/2 (interc.)
try {


if (transaction != null) {
session.flush();
transaction.commit();
}

return result;

} catch (Exception e) {

transaction.rollback();
throw e;

} finally {

if (transaction != null) {
hibernateSessionService.closeSession(session);
sessionStack.pop();
if (sessionStack.isEmpty())
sessionThreadLocal.remove();
}

service.setSession(oldSession);

}

}

}


Demo 4 – Transazioni (bind)

@Override


@Override


...




TransactionInterceptor transactionInterceptor =
new TransactionInterceptor();
requestInjection(transactionInterceptor);
bindInterceptor(Matchers.annotatedWith(Transactional.class),
Matchers.not(Matchers.annotatedWith(NoTransactional.class)),
TransactionInterceptor);


Demo 5 - Login Cookie (bind)
Annotation:
AuthenticatedUser
ApplicationRolesAllowed
Provider:
AuthenticatedUserProvider
Exception e ExceptionMapper:
NotAuthenticatedException(+Mapper)
NotAuthorizedException(+Mapper)
Cookie: LoginCookieManager
Utente: DemoPrincipal
Interceptor: ApplicationRolesAllowedInterceptor

Grazie!

Domande??

Riferimenti:
http://jersey.java.net
http://code.google.com/p/google-guice/
Demo webapp:
https://github.com/dometec/shadedcode/tree/master/demo-webapp


Jersey Guice AOP

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