Apache DeltaSpike - the CDI toolbox

Rafael Benevides

  • DeltaSpike P.M.C member
  • Red Hat, Inc.
  • @rafabene
  • rafabene.com
  • github.com/rafabene

Antoine Sabot-Durand

  • CDI spec lead
  • Red Hat, Inc.
  • @antoine_sd
  • next-presso.com
  • github.com/antoinesd

Should I stay or should I go?

  • A talk about CDI eco-system
  • Don’t need to be a CDI guru
  • But you need to know CDI

Should I stay or should I go ?

If you know the most of these you can stay


  • What is DeltaSpike ?
  • Core Module
  • Other DeltaSpike Modules
  • Question & Answers

What is DeltaSpike ?


Where does it come from ?


A bit of history

  • Dec 2011: project launch
  • Feb 2012: version 0.1
  • May 2013: version 0.4 (out of incubator)
  • June 2014: version 1.0
  • August 2015: version 1.5

CDI & DeltaSpike

CDI is a specification. It doesn’t provide business features
but it includes a powerful hook to add these business features
The "Portable extensions" feature is this hook
Thanks to it, CDI can be easily enhanced with new high level features

CDI Portable extensions

One of the most powerful feature of the CDI specification
Not really popularized, partly due to:
  1. Their high level of abstraction
  2. The good knowledge on Basic CDI and SPI
  3. Lack of information (CDI is often reduced to a basic DI solution)

Extensions, what for?

To integrate 3rd party libraries, frameworks or legacy components
To change existing configuration or behavior
To extend CDI and Java EE
Thanks to them, Java EE can evolve between major releases

Extensions, how?

Observing SPI events at boot time related to the bean manager lifecycle
Checking what meta-data are being created
Modifying these meta-data or creating new ones

More concretely

Service provider of the service javax.enterprise.inject.spi.Extension declared in META-INF/services
Just put the fully qualified name of your extension class in this file
import javax.enterprise.event.Observes;
import javax.enterprise.inject.spi.Extension;

public class CdiExtension implements Extension {

    void beforeBeanDiscovery(@Observes BeforeBeanDiscovery bbd) {

    void afterDeploymentValidation(@Observes AfterDeploymentValidation adv) {

Bean manager lifecycle

lifecycle simple lifecycle legend

Example: Ignoring JPA entities

The following extension prevents CDI to manage entities
This is a commonly admitted good practice
public class VetoEntity implements Extension {

    void vetoEntity(@Observes @WithAnnotations(Entity.class)
                    ProcessAnnotatedType<?> pat) {


Extensions are launched during
and are based on CDI events

Once the application is bootstrapped,
the Bean Manager is in read-only mode (no runtime bean registration)

You only have to @Observes built-in CDI events to create your extensions

Apache DeltaSpike is…​

A collection of ready to use extensions to help you in your projects
A toolbox to help you develop new CDI portable extensions
A great way to learn how to develop your own extension by browsing the source code
The most obvious entry point to CDI eco-system

DeltaSpike is tested with

  • CDI 1.0, 1.1, 1.2 and 2.0
  • JBoss Weld and Apache OpenWebBeans
  • JBoss AS 7.x, WildFly 8.x - 10.x
  • JBoss EAP 6.x - 7.x
  • Apache TomEE 1.0.x - 1.7.x
  • Oracle GlassFish 3.x, 4.x
  • Oracle Weblogic 12c
  • IBM Websphere 8.x

Deltaspike is for all CDI developers

While this talk is focused on classical project developers…​
…​advanced developers may find interesting helpers in Deltaspike
For instance metadata builder are useful for portable extension developers
public void registerGenericBeans(@Observes AfterBeanDiscovery abd) {

    BeanBuilder<User> ubb = new BeanBuilder<User>(beanManager).readFromType(User.class)



    if (weAreOnWeb)






More on DeltaSpike

Apache DeltaSpike received Duke’s choice award 2014
This talk shows only a small part of the framework

Modules and dependencies


Core Module

Core - Exception Handler

public class InventoryActions {
    @PersistenceContext private EntityManager em;
    @Inject private Event<ExceptionToCatchEvent> catchEvent; (1)

    public Integer queryForItem(Item item) {
        try {
          Query q = em.createQuery("SELECT i from Item i where i.id = :id");
          q.setParameter("id", item.getId());
          return q.getSingleResult();
        } catch (PersistenceException e) {
          catchEvent.fire(new ExceptionToCatchEvent(e)); (2)
1The Event of generic type ExceptionToCatchEvent is injected into your class for use later within a try/catch block.
2The event is fired with a new instance of ExceptionToCatchEvent constructed with the exception to be handled.

Core - Exception Handler

Exceptions are handled asynchronously.
@ExceptionHandler  (1)
public class MyHandlers {
    void printExceptions(@Handles ExceptionEvent<Throwable> evt) { (2)
        System.out.println("Something bad happened:" +
        evt.handleAndContinue(); (3)
1Exception handler methods are registered on beans annotated with @ExceptionHandler
2The @Handles annotation on the first parameter designates this method as an exception handler.
3This handler does not modify the invocation of subsequent handlers, as designated by invoking handleAndContinue().

Core - Type-safe ProjectStage

The current ProjectStage can be injected.
private ProjectStage projectStage;


boolean isDevelopment = ProjectStage.Development.equals(this.projectStage);
You can also use the ProjectStage at XHTML files.
<h:panelGroup layout="block"rendered="#{applicationConfig.projectStage == 'Development'}" >
    <!-- HTML Snippet is shown only in Development stage -->

Core - Type-safe ProjectStage

DeltaSpike comes with the following pre-defined ProjectStages:
  1. UnitTest
  2. Development
  3. SystemTest
  4. IntegrationTest
  5. Staging
  6. Production
But you can create your own custom ProjectStages.

Core - Project Stage Configuration

It can be set using DeltaSpike Configuration Mechanism
-D org.apache.deltaspike.ProjectStage=Development

How to provide these Key/Values to DeltaSpike?

  1. System properties
  2. Environment properties
  3. JNDI values - the base name is "java:comp/env/deltaspike/"
  4. Properties file values - default filename is "META-INF/apache-deltaspike.properties"

Core - DeltaSpike Configuration Mechanism

Configuration API
String userName = ConfigResolver.getPropertyValue("user.name");  (1)
String dbUserName = ConfigResolver.getProjectStageAwarePropertyValue("db.username"); (2)
Integer dbPort = ConfigResolver
    .resolve("db.port")  (3)
Date deadline = ConfigResolver.resolve("project.deadline") (4)
  .as(Date.class, new CustomDateConverter()).getValue());
Properties (Key / Value)
user.name = "Rafael"  (1)
db.username.Production = "Antoine" (2)
db.username.Development = "Benevides" (2)
db.port = 1234 (3)
project.deadline = 2017-04-01 (4)

Core - DeltaSpike Configuration Mechanism

Injection of configured values into beans using @ConfigProperty
public class SomeRandomService
    @ConfigProperty(name = "endpoint.poll.interval")
    private Integer pollInterval;

    @ConfigProperty(name = "endpoint.poll.servername")
    private String pollUrl;


Core - Messages and i18n

Type-safe messages - Bean creation
public interface MyMessages {

    public String welcome();

    public String welcomeTo(String username); (1)

    @MessageTemplate("{custom_message}")  (2)
    public String message();
1in the message bundle: welcometo=Welcome to %s
2in the message bundle: custom_message=DeltaSpike is awesome!

Core - Messages and i18n

Now the messages bean is ready to be used in Java Classes
private MyMessages messages;
new FacesMessage(messages.welcomeTo("Rafael"));
…​or even inside JSP/JSF because it uses a @Named annotation.
It uses the “partial bean” module to dynamically create implementation at runtime.

Core - @Exclude

It’s like @Vetoed from CDI 1.1 but better!
Excluding a Bean in any Case
public class NoBean{  }
Excluding a Bean in Case of ProjectStageDevelopment
@Exclude(ifProjectStage = ProjectStage.Development.class)
public class MyBean{  }
Excluding a Bean if the ProjectStage is different from Development
@Exclude(exceptIfProjectStage = ProjectStage.Development.class)
public class MyDevBean{ }
Excluding a Bean based on an Expression which Evaluates to True
@Exclude(onExpression = "db==prodDB")
public class DevDbBean {  }

Core - Injecting Resources

DeltaSpike has simple APIs for performing basic resource loading and property file reading.
private InputStream is;

public String getVersion() throws IOException {
    try (BufferedReader br = new BufferedReader(new InputStreamReader(is))) {
      return br.readLine();
The InjectableResourceProvider interface can be implemented to allow reading from alternate sources if needed.

Data Module

Data Module

Data module is an implementation of the repository pattern.
At the moment it only support RDBMS thru JPA.
But it could be extended to support other data services.

Repository pattern

"A Repository represents
all objects of a certain type as
a conceptual set.

It acts like a collection, except with more elaborate querying capability."

Domain Driven Design
Eric Evans

Data Module - Creating a Repository

public interface UserRepository extends EntityRepository<User, Long> {
/* DeltaSpike creates a proxy which implements:

Long count();
List<E> findAll();
E findBy(PK);
void flush();
void refresh();
void remove(E);
E save(E);
E saveAndFlush(E);

...and many others */
It uses the “partial bean” module to dynamically create implementation at runtime.

Data Module - Making queries

public interface UserRepository extends EntityRepository<User, Long> {

  public User findByUsernameAndPassword(String username, char[] password); (1)

  @Query("SELECT u FROM User AS u WHERE u.role in (?1)") (2)
  public List<Role> findByRoles(List<Role> roles);

1The name of the method automatically creates the query. Example:
"SELECT u FROM User u WHERE u.username = ?1 AND u.password = ?2 "
2The query is defined inside the @Query annotation.

Data Module - Pagination

public interface UserRepository extends EntityRepository<User, Long> {

  @Query("select p from Person p where p.age between ?1 and ?2")
  QueryResult<Person> findAllByAge(int minAge, int maxAge);


QueryResult<Person> paged = personRepository.findByAge(age)

// Query API style

// or paging style

int totalPages = paged.countPages();

Security Module

Security Module - Simple interceptor-style authorization

Type-safe authorization
@Retention(value = RetentionPolicy.RUNTIME)
@Target({ ElementType.TYPE, ElementType.METHOD })
public @interface AdminOnly {

public class SecuredBean {

    public void doSomething() {

Security Module - Simple interceptor-style authorization

An interceptor-style class is used to define the access
public class ApplicationAuthorizer {

    public boolean verifyPermission(InvocationContext invocationContext, BeanManager manager, @Loggged User user) throws Exception {
      return user.getRole().equalsIgnoreCase("Admin");

JSF Module

JSF Module - JSF Messages

public interface Messages {

    @MessageTemplate("Welcome to DeltaSpike")
    String welcomeToDeltaSpike();


public class MyJSFBean {

    private JsfMessage<Messages> messages;


JSF Module - @WindowScoped

"The window-scope is like a session per window"
public class PreferencesBean implements Serializable {
"There isn’t a lot of use-cases which need shared data between windows"

JSF Module - Double-Submit Prevention

"To avoid that the same content of a form gets submitted and therefore processed multiple times"
<html xmlns="http://www.w3.org/1999/xhtml"
        <!-- head content -->
            <!-- form content -->

Scheduler Module

Scheduler Module

Provides integration with Quartz.
// Job will execute each minute
@Scheduled(cronExpression = "0 0/1 * * * ?", onStartup = false)
public class CdiAwareQuartzJob implements org.quartz.Job {

    // And it can receive CDI injections
    private AdminServices service;

    public void execute(JobExecutionContext context) throws JobExecutionException {
private Scheduler<Job> jobScheduler;


Other Modules

Other Modules


Want to go farther on CDI?

TUT2376: Advanced CDI in live coding

Tuesday 27th at 8:30

Cyril Magnin II / III

Antonin Stefanutti & Antoine SD

Questions ???