Ironic programmer: Payara

Showing posts with label Payara. Show all posts

Sunday, October 11, 2015

Playing with Hazelcast on Payara

I have been reading a bit about Hazelcast, came up to chapter 5 in http://hazelcast.org/mastering-hazelcast/, but as I am a bit impatient and wanted to try out some stuff before reading the whole book and thinking about possibilities to use Hazelcast in my current work, this Weekend I set up to solve the following:

Use Hazelcast IMap in a Java EE container
Use MapLoader to load into a IMap with JPA
As far as possible, use CDI

Payara comes with a Hazelcast, but solving this tasks may not be so straightforward, and I will try to explain why.

As usual I use a simple blog Post RESTful service as an example.

#%RAML 0.8
title: Blog post service 
baseUri: http://localhost:8080/hazelblog/api
version: v1
/posts:   
   get:
      description: Gets a list of "Posts"
      queryParameters:
         author: 
            displayName: Author
            type: string
            description: Name of the author
            example: @ironic
      responses:
         200:
            body: 
               application/json:
                  example: |
                     [
                        {"author":"@ironic","content":"Nothing interesting","id":1,"title":"First post"},
                        {"author":"@ironic","content":"Again nothing interesting","id":2,"title":"Second post"}
                    ]
   post:
      description: Creates a post
      body: 
         application/json:
            example: |
               {"author":"@ironic","content":"Nothing interesting", "title":"Test post"}
   /{id}:
      get:
         description: View of a post
         responses:
            200:
               body: 
                  application/json:
                     example: |
                        {"author":"@ironic","content":"Nothing interesting","id":1,"title":"First post"}                     
      delete:  
         description: Deletes a post

Using Hazlecast in Payara

Even if Payara comes with an embedded Hazelcast, I will not use it by letting Payara start it, and the reason is what I found when playing around with EntryListener. I will however use the Hazelcast that is provided, but will not activate it as written here: https://github.com/payara/Payara/wiki/Hazelcast-%28Payara-4.1.153%29 but more with ideas as written here: http://blog.modernjava.info/2014/10/using-hazelcast-as-jcache-provider-with.html.

To start with, this is what we will need in the pom.xml,

I am using Hazelcast 3.5 since that is the one that comes with Payara 4.153.

To fire up Hazelcast we will use an annotation and a provider so we can use CDI where we want to use stuff from Hazelcast.

package se.ironic.hazelblog;

import com.hazelcast.config.Config;
import com.hazelcast.config.MapStoreConfig;
import com.hazelcast.core.HazelcastInstance;
import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.inject.Disposes;
import javax.enterprise.inject.Produces;
import javax.inject.Singleton;

@ApplicationScoped
public class HazelcastProvider {

@Produces
    @Singleton
    @Hazelcast
    public HazelcastInstance create() {
        System.out.println("Creating Hazelcast Instance");
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        Config config = new Config();

MapStoreConfig storeConfig = new MapStoreConfig();
        storeConfig.setEnabled(true);
        storeConfig.setClassName("se.ironic.hazelblog.PostLoader");
        config.getMapConfig("posts").setMapStoreConfig(storeConfig);
        HazelcastInstance newInst = com.hazelcast.core.Hazelcast.newHazelcastInstance(config);

return newInst;
    }

public void close(@Disposes @Hazelcast HazelcastInstance instance) {
        System.out.println("Shutting down Hazelcast....");
        instance.shutdown();
    }
}

The reason for doing like this is that I noticed by playing around with EntryListener that by letting Payara firing up Hazelcast I cannot really add listeners, since Hazelcast then know nothing about my classes (resulting in ClassNotFoundException), so to resolve this we need to provide the class loader from our web-application to Hazelcast. To do this we need to start it "manually" and provide the class loader so Hazelcast knows about them. You can also see we configure Hazelcast with a MapLoader, more on that later.

REST-resource

I will not share the full code since you can find it on Bitbucket. In PostResource we use CDI to get hold of the Hazelcast, it will initialise on first use, so if no pre-warming occurs (like using a startup bean) it will take 5-10 seconds.

And use it

For the creation of a Post we can use a trick to load it in the map by trying to get it after the save. That is we don't put it in the map directly and use a MapStore to save it (we don't know the id until after the persist). But since this is about using MapLoader, we will use that and not put it (as indicated in the comments)

MapLoader using JPA

Actually, I am not using it directly from the MapLoader, but injecting a @Statless bean from it, that does the actual JPA stuff.
As the MapLoader lives in Hazelcast and is created by it, we cannot use @Inject or even make it a managed bean (well we can, but it will not help since it is not using the jave ee container to handle it). But since CDI 1.1 we can inject using the CDI-class.

This is how the map loader I create looks like:

package se.ironic.hazelblog;

import com.hazelcast.core.MapLoader;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.enterprise.inject.spi.CDI;

public class PostLoader implements MapLoader<Long, Post> {

@Override
    public Post load(Long id) {
        PostRepository repo = CDI.current().select(PostRepository.class).get();
        Post post = repo.find(id);
        return post;
    }

@Override
    public Map<Long, Post> loadAll(Collection<long> ids) {
        Map<Long, Post> all = new HashMap<>();
        PostRepository repo = CDI.current().select(PostRepository.class).get();
        Map<String, Object> params = new HashMap<>();
        params.put("ids", ids);
        List<post> posts = repo.findByQuery("SELECT p FROM Post p WHERE p.id in :ids", params);
        for (Post post : posts) {
            all.put(post.getId(), post);
            System.out.println("Post: " + post);
        }
        return all;
    }

@Override
    public Iterable<long> loadAllKeys() {
        PostRepository repo = CDI.current().select(PostRepository.class).get();
        List<long> ids = repo.findByQuery("SELECT p.id FROM Post p", Collections.EMPTY_MAP);
        return ids;
    }

}

Notice the code to inject the PostRepository (which is the bean using JPA with an EntityManager). This will work since Hazelcast is loaded from the container with our classes.

Some notes

I have implemented loadAllKeys() and loadAll(...), this is probably fine since I do not have so many posts, but for a huge database and if you do not want them all in memory, you may leave them empty and return null for keys or you will end up waiting for a while. I played with a criteria search on the map

and found out that by doing that, Hazelcast will try to load all keys from the database before it searcher memory.
However, this is done only once, if you add items to the database, it will not get loaded if you do not do anything to tell the map, as you have seen in the "@POST" or put it there yourself, subsequent searches on the map will not try to load items not there from the first loadAll.

Payara does not really matter in the context, other than having a Hazelcast and being a Java EE container. But I also use it since it have a default datasource for Derby, so I kind of used that to avoid setting up a database, and load a few posts to get started.If you use another container, you may have to change the hazelnuts dependency to be "compile" instead of "provided" if that container donate have it. You may also need to set up a datasource.

The code can be found here: [https://bitbucket.org/pejomstd/hazelblog]

Tuesday, May 19, 2015

Payara Micro, even easier

Just saw this post. [http://java.dzone.com/articles/java-ee-embedded-and-micro]. It is not even nescessary to build a runner, using Payara Micro, it is as easy as this:

More here:http://www.payara.co.uk/introducing_payara_micro

RESTful Service on an embedded Glassfish/Payara

Last posts were about making a RESTFul service and run it on Jersey with an embedded Jetty.
This time I will set up a more Java EE like solution with the same REST Resource, but instead run it on an embedded Glassfish (actually, I will go for Payara). I will take the same model as before. Next part I will also add a JSF 2.2 client to use the RESTful service.

I will create this as a maven multi module with a parent project and two subprojects. One will be a web-project and the other will be a "runner" for the embedded Glassfish. I will not use maven to run, but will create a class that will run the embedded Glassfish with the war-file from the other project.

As it is pretty easy I use NetBeans to create maven projects for me.

The structure will be like this:

embgf

task-web
gf-runner
pack-dist

task-web

To start with, instead of having to set up a Servlet on "/api" path, we will create a configuration class that extends JAX_RSs Application.

And this will be the class for the Task service.

package se.ironic.task.boundary;

import java.net.URI;
import java.util.List;
import java.util.Optional;
import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import se.ironic.task.model.Task;

/**
 *
 * @author Ironic
 */
@Path("tasks")
public class TaskResource {
    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public List<task> getAll() {
        return TaskCache.INST.getTasks();
    }
    
    @POST
    @Consumes(MediaType.APPLICATION_JSON)
    public Response create(Task task) {
        TaskCache.INST.putTask(task);
        URI id = URI.create("tasks/" + task.getId());
        Response resp = Response.created(id).build();
        return resp;
    }

@GET
    @Produces(MediaType.APPLICATION_JSON)
    @Path("{id}")
    public Response getTask(@PathParam("id") String id) {
        Optional<task> task = TaskCache.INST.getTask(id);
        Response resp = null;
        if (task.isPresent()) {
            resp = Response.ok(task.get()).build();
        } else {
            resp = Response.noContent().build();
        }
        return resp;
    }
    
    @PUT @Consumes(MediaType.APPLICATION_JSON)
    @Path("{id}")
    public Response update(Task task) {
        // Just replace the one there
        TaskCache.INST.putTask(task);
        return Response.ok().build();
    }
    
    @DELETE
    @Path("{id}")
    public Response delete(@PathParam("id") String id) {
        System.out.println("Deleting task: " + id);
        TaskCache.INST.removeTask(id);
        return Response.ok().build();
    }
}

The service will be available at [http://localhost:2001/task-web/api/tasks] (depending what you use as port and contextRoot)
Just to have some Tasks to start with since we have a simple cache in a HashMap, we create a startup bean to create some.

gf-runner

Embedded Payara

Trying to follow [http://www.payara.co.uk/using_payara_embedded_and_payara_micro_with_mav] I ran in to some issues. The dependency on that page does not really work, it end up with the following message:

There is a bug-report on this. But to get on, I will download the jar and do a "quickie" and add it as a system dependency and get on.

The code to get up and running with the war-file from task-web on an embedded Payara is just a few lines:

package se.ironic.gfrunner;

import java.io.File;
import org.glassfish.embeddable.BootstrapProperties;
import org.glassfish.embeddable.GlassFish;
import org.glassfish.embeddable.GlassFishException;
import org.glassfish.embeddable.GlassFishProperties;
import org.glassfish.embeddable.GlassFishRuntime;

public class EmbeddedGFRunner {

public static void main(String[] args) throws GlassFishException {
        if(args.length != 3) {
            System.out.println("Usage > EmbeddedGFRunner \"port\" \"deployable.war\" \"contextRoot\"");
            System.exit(1);
        }
        int port = Integer.parseInt(args[0]);
        BootstrapProperties bootstrap = new BootstrapProperties();
        GlassFishRuntime runtime = GlassFishRuntime.bootstrap();
        GlassFishProperties glassfishProperties = new GlassFishProperties();
        glassfishProperties.setPort("http-listener", port);
        GlassFish glassfish = runtime.newGlassFish(glassfishProperties);
        glassfish.start();
        glassfish.getDeployer().deploy(new File(args[1]), "--contextroot", args[2]);
    }
}

pack-dist

As I am a bit lazy and want to avoid copy jars manually I created a pom-project just to copy dependencies. The needed jar file will end up in the root folders under ./dist/, I also added a bat file to start the embedded Payara with the following content:

I also tried the jersey-client from the previous post with s slight modification for the context-path and it still works. (or you can start the payara with "/" as context path)

In next part I will add a JSF client on top of this service to show some nice stuff in Java EE 7 and JSF 2.2.

[The full project can be found at: https://bitbucket.org/pejomstd/embedded-gf-payara]

Ironic programmer