Writing REST Services with Quarkus REST (formerly RESTEasy Reactive)

<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-rest</artifactId>
</dependency>

implementation("io.quarkus:quarkus-rest")

package org.acme.rest;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

@Path("")
public class Endpoint {

    @GET
    public String hello() {
        return "Hello, World!";
    }
}

package org.acme.rest;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

@Path("rest")
public class Endpoint {

    @Path("hello")
    @GET
    public String hello() {
        return "Hello, World!";
    }
}

package org.acme.rest;

import jakarta.ws.rs.ApplicationPath;
import jakarta.ws.rs.core.Application;

@ApplicationPath("/api")
public static class MyApplication extends Application {

}

package org.acme.rest;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

import jakarta.ws.rs.HttpMethod;
import jakarta.ws.rs.Path;

@Retention(RetentionPolicy.RUNTIME)
@HttpMethod("CHEESE")
@interface CHEESE {
}

@Path("")
public class Endpoint {

    @CHEESE
    public String hello() {
        return "Hello, Cheese World!";
    }
}

POST /cheeses;variant=goat/tomme?age=matured HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Cookie: level=hardcore
X-Cheese-Secret-Handshake: fist-bump

smell=strong

package org.acme.rest;

import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;

import org.jboss.resteasy.reactive.RestCookie;
import org.jboss.resteasy.reactive.RestForm;
import org.jboss.resteasy.reactive.RestHeader;
import org.jboss.resteasy.reactive.RestMatrix;
import org.jboss.resteasy.reactive.RestPath;
import org.jboss.resteasy.reactive.RestQuery;

@Path("/cheeses/{type}")
public class Endpoint {

    @POST
    public String allParams(@RestPath String type,
                            @RestMatrix String variant,
                            @RestQuery String age,
                            @RestCookie String level,
                            @RestHeader("X-Cheese-Secret-Handshake")
                            String secretHandshake,
                            @RestForm String smell) {
        return type + "/" + variant + "/" + age + "/" + level + "/"
            + secretHandshake + "/" + smell;
    }
}

package org.acme.rest;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

@Path("hello")
public class Endpoint {

    @Path("{name}/{age:\\d+}")
    @GET
    public String personalisedHello(String name, int age) {
        return "Hello " + name + " is your age really " + age + "?";
    }

    @GET
    public String genericHello() {
        return "Hello stranger";
    }
}

import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.MediaType;

import org.jboss.resteasy.reactive.PartType;
import org.jboss.resteasy.reactive.RestForm;
import org.jboss.resteasy.reactive.multipart.FileUpload;

@Path("multipart")
public class MultipartResource {
    public static class Person {
        public String firstName;
        public String lastName;
    }

    @POST
    public void multipart(@RestForm String description,
            @RestForm("image") FileUpload file,
            @RestForm @PartType(MediaType.APPLICATION_JSON) Person person) {
        // do something
    }
}

package org.acme.rest;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import io.smallrye.mutiny.Uni;

@Path("escoffier")
public class Endpoint {

    @GET
    public Uni<Book> culinaryGuide() {
        return Book.findByIsbn("978-2081229297");
    }
}

package org.acme.rest;

import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import org.eclipse.microprofile.reactive.messaging.Channel;

import io.smallrye.mutiny.Multi;

@Path("logs")
public class Endpoint {

    @Inject
    @Channel("log-out")
    Multi<String> logs;

    @GET
    public Multi<String> streamLogs() {
        return logs;
    }
}

package org.acme.rest;

import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import io.smallrye.mutiny.Multi;
import org.jboss.resteasy.reactive.RestMulti;

@Path("message-stream")
public class Endpoint {
    @GET
    public Multi<String> streamMessages() {
        Multi<String> sourceMulti = Multi
            .createBy()
            .merging()
            .streams(
                Multi.createFrom().items(
                    "message-1",
                    "message-2",
                    "message-3",
                    "message-4",
                    "message-5"
                )
            );

        return RestMulti
            .fromMultiData(sourceMulti)
            .withDemand(5)
            .build();
    }
}

"message-3"
"message-5"
"message-4"
"message-1"
"message-2"

"message-1"
"message-2"
"message-3"
"message-4"
"message-5"

package org.acme.rest;

import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import io.smallrye.mutiny.Multi;
import org.jboss.resteasy.reactive.RestMulti;

@Path("message-stream")
public class Endpoint {
    @GET
    public Multi<String> streamMessages() {
        Multi<String> sourceMulti = Multi
            .createBy()
            .merging()
            .streams(
                Multi.createFrom().items(
                    "message-1",
                    "message-2",
                    "message-3",
                    "message-4",
                    "message-5"
                )
            );

        return RestMulti
            .fromMultiData(sourceMulti)
            .encodeAsJsonArray(false)
            .build();
    }
}

package org.acme.rest;

import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

import org.jboss.resteasy.reactive.RestStreamElementType;

import io.smallrye.mutiny.Multi;

import org.eclipse.microprofile.reactive.messaging.Channel;

@Path("escoffier")
public class Endpoint {

    // Inject our Book channel
    @Inject
    @Channel("book-out")
    Multi<Book> books;

    @GET
    // Each element will be sent as JSON
    @RestStreamElementType(MediaType.APPLICATION_JSON)
    // by using @RestStreamElementType, we don't need to add @Produces(MediaType.SERVER_SENT_EVENTS)
    public Multi<Book> stream() {
        return books;
    }
}

package org.acme.rest;

import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;
import jakarta.ws.rs.sse.OutboundSseEvent;
import jakarta.ws.rs.sse.Sse;

import org.jboss.resteasy.reactive.RestStreamElementType;

import io.smallrye.mutiny.Multi;

import org.eclipse.microprofile.reactive.messaging.Channel;

@Path("escoffier")
public class Endpoint {

    @Inject
    @Channel("book-out")
    Multi<Book> books;

    @Inject
    Sse sse; 1

    @GET
    @RestStreamElementType(MediaType.TEXT_PLAIN)
    public Multi<OutboundSseEvent> stream() {
        return books.map(book -> sse.newEventBuilder() 2
            .name("book")  3
            .data(book.title) 4
            .build());
    }
}

package org.acme.rest;

import java.security.Principal;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.SecurityContext;

@Path("user")
public class Endpoint {

    @GET
    public String userName(SecurityContext security) {
        Principal user = security.getUserPrincipal();
        return user != null ? user.getName() : "<NOT LOGGED IN>";
    }
}

package org.acme.rest;

import java.security.Principal;

import jakarta.inject.Inject;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.SecurityContext;

@Path("user")
public class Endpoint {

    @Inject
    SecurityContext security;

    @GET
    public String userName() {
        Principal user = security.getUserPrincipal();
        return user != null ? user.getName() : "<NOT LOGGED IN>";
    }
}

package org.acme.rest;

import java.security.Principal;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.SecurityContext;

@Path("user")
public class Endpoint {

    SecurityContext security;

    Endpoint(SecurityContext security) {
        this.security = security;
    }

    @GET
    public String userName() {
        Principal user = security.getUserPrincipal();
        return user != null ? user.getName() : "<NOT LOGGED IN>";
    }
}

public class Record {

    // The class must contain/inherit either and `id` field, an `@Id` or `@RestLinkId` annotated field.
    // When resolving the id the order of preference is: `@RestLinkId` > `@Id` > `id` field.
    private int id;

    public Record() {
    }

    protected Record(int id) {
        this.id = id;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }
}

@Path("/records")
public class RecordsResource {

    @GET
    @RestLink(rel = "list")
    @InjectRestLinks
    public List<Record> getAll() {
        // ...
    }

    @GET
    @Path("/{id}")
    @RestLink(rel = "self")
    @InjectRestLinks(RestLinkType.INSTANCE)
    public Record get(@PathParam("id") int id) {
        // ...
    }

    @PUT
    @Path("/{id}")
    @RestLink
    @InjectRestLinks(RestLinkType.INSTANCE)
    public Record update(@PathParam("id") int id) {
        // ...
    }

    @DELETE
    @Path("/{id}")
    @RestLink
    public Record delete(@PathParam("id") int id) {
        // ...
    }
}

& curl -i localhost:8080/records
Link: <http://localhost:8080/records>; rel="list"

& curl -i localhost:8080/records/1
Link: <http://localhost:8080/records>; rel="list"
Link: <http://localhost:8080/records/1>; rel="self"
Link: <http://localhost:8080/records/1>; rel="update"
Link: <http://localhost:8080/records/1>; rel="delete"

@Path("/records")
public class RecordsResource {

    // ...

    @GET
    @Path("/search/{text}")
    @RestLink(rel = "search records by free text")
    @InjectRestLinks
    public List<Record> search(@PathParam("text") String text) { 4
        // ...
    }

    // ...
}

package org.acme.rest;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import io.smallrye.common.annotation.Blocking;

@Path("yawn")
public class Endpoint {

    @Blocking
    @GET
    public Uni<String> blockingHello() throws InterruptedException {
        // do a blocking operation
        Thread.sleep(1000);
        return Uni.createFrom().item("Yaaaawwwwnnnnnn…");
    }
}

package org.acme.rest;

import java.time.Duration;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import io.smallrye.mutiny.Uni;

@Path("yawn")
public class Endpoint {

    @GET
    public Uni<String> blockingHello() throws InterruptedException {
        return Uni.createFrom().item("Yaaaawwwwnnnnnn…")
                // do a non-blocking sleep
                .onItem().delayIt().by(Duration.ofSeconds(2));
    }
}

package org.acme.rest;

import jakarta.ws.rs.BadRequestException;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.NotFoundException;
import jakarta.ws.rs.Path;

@Path("cheeses/{cheese}")
public class Endpoint {

    @GET
    public String findCheese(String cheese) {
        if(cheese == null)
            // send a 400
            throw new BadRequestException();
        if(!cheese.equals("camembert"))
            // send a 404
            throw new NotFoundException("Unknown cheese: " + cheese);
        return "Camembert is a very nice cheese";
    }
}

package org.acme.rest;

import java.util.Map;

import jakarta.enterprise.context.ApplicationScoped;
import jakarta.inject.Inject;
import jakarta.ws.rs.BadRequestException;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.Response;

import org.jboss.resteasy.reactive.server.ServerExceptionMapper;
import org.jboss.resteasy.reactive.RestResponse;

class UnknownCheeseException extends RuntimeException {
    public final String name;

    public UnknownCheeseException(String name) {
        this.name = name;
    }
}

@ApplicationScoped
class CheeseService {
    private static final Map<String, String> cheeses =
            Map.of("camembert", "Camembert is a very nice cheese",
                   "gouda", "Gouda is acceptable too, especially with cumin");

    public String findCheese(String name) {
        String ret = cheeses.get(name);
        if(ret != null)
            return ret;
        throw new UnknownCheeseException(name);
    }
}

@Path("cheeses/{cheese}")
public class Endpoint {

    @Inject
    CheeseService cheeses;

    @ServerExceptionMapper
    public RestResponse<String> mapException(UnknownCheeseException x) {
        return RestResponse.status(Response.Status.NOT_FOUND, "Unknown cheese: " + x.name);
    }

    @GET
    public String findCheese(String cheese) {
        if(cheese == null)
            // send a 400
            throw new BadRequestException();
        return cheeses.findCheese(cheese);
    }
}

package org.acme.rest;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.PUT;
import jakarta.ws.rs.Path;

class Cheese {
    public String name;

    public Cheese(String name) {
        this.name = name;
    }
}

@Path("cheese")
public class Endpoint {

    @GET
    public Cheese sayCheese() {
        return new Cheese("Cheeeeeese");
    }

    @PUT
    public void addCheese(Cheese cheese) {
        System.err.println("Received a new cheese: " + cheese.name);
    }
}

package org.acme.rest;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.nio.charset.StandardCharsets;

import jakarta.ws.rs.WebApplicationException;
import jakarta.ws.rs.core.MediaType;
import jakarta.ws.rs.core.MultivaluedMap;
import jakarta.ws.rs.ext.MessageBodyReader;
import jakarta.ws.rs.ext.MessageBodyWriter;
import jakarta.ws.rs.ext.Provider;

@Provider
public class CheeseBodyHandler implements MessageBodyReader<Cheese>,
                                           MessageBodyWriter<Cheese> {

    @Override
    public boolean isWriteable(Class<?> type, Type genericType,
                               Annotation[] annotations, MediaType mediaType) {
        return type == Cheese.class;
    }

    @Override
    public void writeTo(Cheese t, Class<?> type, Type genericType,
                        Annotation[] annotations, MediaType mediaType,
                        MultivaluedMap<String, Object> httpHeaders,
                        OutputStream entityStream)
            throws IOException, WebApplicationException {
        entityStream.write(("[CheeseV1]" + t.name)
                           .getBytes(StandardCharsets.UTF_8));
    }

    @Override
    public boolean isReadable(Class<?> type, Type genericType,
                              Annotation[] annotations, MediaType mediaType) {
        return type == Cheese.class;
    }

    @Override
    public Cheese readFrom(Class<Cheese> type, Type genericType,
                            Annotation[] annotations, MediaType mediaType,
                            MultivaluedMap<String, String> httpHeaders,
                            InputStream entityStream)
            throws IOException, WebApplicationException {
        String body = new String(entityStream.readAllBytes(), StandardCharsets.UTF_8);
        if(body.startsWith("[CheeseV1]"))
            return new Cheese(body.substring(11));
        throw new IOException("Invalid cheese: " + body);
    }

}

package org.acme.rest;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.nio.charset.StandardCharsets;

import jakarta.ws.rs.WebApplicationException;
import jakarta.ws.rs.core.MediaType;
import jakarta.ws.rs.core.MultivaluedMap;
import jakarta.ws.rs.ext.MessageBodyReader;
import jakarta.ws.rs.ext.Provider;

import org.jboss.resteasy.reactive.server.spi.ResteasyReactiveResourceInfo;
import org.jboss.resteasy.reactive.server.spi.ServerMessageBodyWriter;
import org.jboss.resteasy.reactive.server.spi.ServerRequestContext;

@Provider
public class CheeseBodyHandler implements MessageBodyReader<Cheese>,
                                           ServerMessageBodyWriter<Cheese> {

    // …

    @Override
    public boolean isWriteable(Class<?> type, ResteasyReactiveResourceInfo target,
                               MediaType mediaType) {
        return type == Cheese.class;
    }

    @Override
    public void writeResponse(Cheese t, ServerRequestContext context)
      throws WebApplicationException, IOException {
        context.serverResponse().end("[CheeseV1]" + t.name);
    }
}

package org.acme.rest;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.PUT;
import jakarta.ws.rs.Path;

@Path("cheese")
public class Endpoint {

    @GET
    public String sayCheese() {
        return "Cheeeeeese";
    }

    @PUT
    public void addCheese(String cheese) {
        System.err.println("Received a new cheese: " + cheese);
    }
}

package org.acme.rest;

import java.io.IOException;

import jakarta.ws.rs.WebApplicationException;
import jakarta.ws.rs.ext.Provider;
import jakarta.ws.rs.ext.ReaderInterceptor;
import jakarta.ws.rs.ext.ReaderInterceptorContext;
import jakarta.ws.rs.ext.WriterInterceptor;
import jakarta.ws.rs.ext.WriterInterceptorContext;

@Provider
public class CheeseIOInterceptor implements ReaderInterceptor, WriterInterceptor {

    @Override
    public void aroundWriteTo(WriterInterceptorContext context)
      throws IOException, WebApplicationException {
        System.err.println("Before writing " + context.getEntity());
        context.proceed();
        System.err.println("After writing " + context.getEntity());
    }

    @Override
    public Object aroundReadFrom(ReaderInterceptorContext context)
      throws IOException, WebApplicationException {
        System.err.println("Before reading " + context.getGenericType());
        Object entity = context.proceed();
        System.err.println("After reading " + entity);
        return entity;
    }
}

package org.acme.rest;

import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.List;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.ext.ParamConverter;
import jakarta.ws.rs.ext.ParamConverterProvider;
import jakarta.ws.rs.ext.Provider;

import org.jboss.resteasy.reactive.RestQuery;

@Provider
class MyConverterProvider implements ParamConverterProvider {

    @Override
    public <T> ParamConverter<T> getConverter(Class<T> rawType, Type genericType,
                                              Annotation[] annotations) {
        // declare a converter for this type
        if(rawType == Converter.class) {
            return (ParamConverter<T>) new MyConverter();
        }
        return null;
    }

}

// this is my custom converter
class MyConverter implements ParamConverter<Converter> {

    @Override
    public Converter fromString(String value) {
        return new Converter(value);
    }

    @Override
    public String toString(Converter value) {
        return value.value;
    }

}

// this uses a converter
class Converter {
    String value;
    Converter(String value) {
        this.value = value;
    }
}

class Constructor {
    String value;
    // this will use the constructor
    public Constructor(String value) {
        this.value = value;
    }
}

class ValueOf {
    String value;
    private ValueOf(String value) {
        this.value = value;
    }
    // this will use the valueOf method
    public static ValueOf valueOf(String value) {
        return new ValueOf(value);
    }
}

@Path("hello")
public class Endpoint {

    @Path("{converter}/{constructor}/{primitive}/{valueOf}")
    @GET
    public String conversions(Converter converter, Constructor constructor,
                              int primitive, ValueOf valueOf,
                              @RestQuery List<Constructor> list) {
        return converter + "/" + constructor + "/" + primitive
               + "/" + valueOf + "/" + list;
    }
}

package org.acme.rest;

import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalUnit;
import java.util.Date;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.PUT;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.EntityTag;
import jakarta.ws.rs.core.Request;
import jakarta.ws.rs.core.Response;
import jakarta.ws.rs.core.Response.ResponseBuilder;

@Path("conditional")
public class Endpoint {

    // It's important to keep our date on seconds because that's how it's sent to the
    // user in the Last-Modified header
    private Date date = Date.from(Instant.now().truncatedTo(ChronoUnit.SECONDS));
    private int version = 1;
    private EntityTag tag = new EntityTag("v1");
    private String resource = "Some resource";

    @GET
    public Response get(Request request) {
        // first evaluate preconditions
        ResponseBuilder conditionalResponse = request.evaluatePreconditions(date, tag);
        if(conditionalResponse != null)
            return conditionalResponse.build();
        // preconditions are OK
        return Response.ok(resource)
                .lastModified(date)
                .tag(tag)
                .build();
    }

    @PUT
    public Response put(Request request, String body) {
        // first evaluate preconditions
        ResponseBuilder conditionalResponse = request.evaluatePreconditions(date, tag);
        if(conditionalResponse != null)
            return conditionalResponse.build();
        // preconditions are OK, we can update our resource
        resource = body;
        date = Date.from(Instant.now().truncatedTo(ChronoUnit.SECONDS));
        version++;
        tag = new EntityTag("v" + version);
        return Response.ok(resource)
                .lastModified(date)
                .tag(tag)
                .build();
    }
}

HTTP/1.1 200 OK
Content-Type: text/plain;charset=UTF-8
ETag: "v1"
Last-Modified: Wed, 09 Dec 2020 16:10:19 GMT
Content-Length: 13

Some resource

GET /conditional HTTP/1.1
Host: localhost:8080
If-Modified-Since: Wed, 09 Dec 2020 16:10:19 GMT

HTTP/1.1 304 Not Modified

PUT /conditional HTTP/1.1
Host: localhost:8080
If-Unmodified-Since: Wed, 09 Dec 2020 16:25:43 GMT
If-Match: v1
Content-Length: 8
Content-Type: text/plain

newstuff

HTTP/1.1 412 Precondition Failed
ETag: "v2"
Content-Length: 0

package org.acme.rest;

import jakarta.ws.rs.Consumes;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.PUT;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

import com.fasterxml.jackson.annotation.JsonCreator;

class Cheese {
    public String name;
    @JsonCreator
    public Cheese(String name) {
        this.name = name;
    }
    @Override
    public String toString() {
        return "Cheese: " + name;
    }
}

@Path("negotiated")
public class Endpoint {

    @Produces({MediaType.APPLICATION_JSON, MediaType.TEXT_PLAIN})
    @GET
    public Cheese get() {
        return new Cheese("Morbier");
    }

    @Consumes(MediaType.TEXT_PLAIN)
    @PUT
    public Cheese putString(String cheese) {
        return new Cheese(cheese);
    }

    @Consumes(MediaType.APPLICATION_JSON)
    @PUT
    public Cheese putJson(Cheese cheese) {
        return cheese;
    }
}

> GET /negotiated HTTP/1.1
> Host: localhost:8080
> Accept: application/json

< HTTP/1.1 200 OK
< Content-Type: application/json
< Content-Length: 18
<
< {"name":"Morbier"}

> GET /negotiated HTTP/1.1
> Host: localhost:8080
> Accept: text/plain
>
< HTTP/1.1 200 OK
< Content-Type: text/plain
< Content-Length: 15
<
< Cheese: Morbier

> PUT /negotiated HTTP/1.1
> Host: localhost:8080
> Content-Type: application/json
> Content-Length: 16
>
> {"name": "brie"}

< HTTP/1.1 200 OK
< Content-Type: application/json;charset=UTF-8
< Content-Length: 15
<
< {"name":"brie"}

> PUT /negotiated HTTP/1.1
> Host: localhost:8080
> Content-Type: text/plain
> Content-Length: 9
>
> roquefort

< HTTP/1.1 200 OK
< Content-Type: application/json;charset=UTF-8
< Content-Length: 20
<
< {"name":"roquefort"}

@IfBuildProfile("app1")
public class ResourceForApp1Only {

    @GET
    @Path("sayHello")
    public String sayHello() {
        return "hello";
     }
}

@EndpointDisabled(name = "some.property", stringValue = "disable")
public class RuntimeResource {

    @GET
    @Path("sayHello")
    public String sayHello() {
        return "hello";
     }
}