What are CDI Producers?

Ahoy there mateys! Today, we’ll be setting sail on an adventure to explore the depths of CDI producers. Now, you may be wondering what exactly a CDI producer is, so let me explain.

CDI producers are an essential component of the CDI framework that allow you to create instances of beans that cannot be instantiated by the container. In other words, they help you to create beans that are not automatically created by the container, but rather need some custom logic to create them.

Now, you may be asking yourself, “Why would I need to create beans in such a way?” Well, imagine you have a bean that requires some complex initialization logic or needs to be created based on user input. In such cases, a CDI producer can come to your rescue by allowing you to create these beans with the necessary custom logic.

To put it in pirate terms, a CDI producer is like having a ship builder who can construct ships to your specifications, with custom features and modifications to fit your needs. In the same way, a CDI producer can create a bean tailored to your specific requirements, with custom logic to initialize it just the way you want.

In our next section, we’ll explore how to use CDI producers to create these custom beans. So hoist the anchor, set sail and let’s delve deeper into the world of CDI producers.

How they are used to create instances of beans that can’t be instantiated by the container:

To create a CDI producer, you’ll need to use the @Produces annotation. This annotation is applied to a method that returns an instance of the bean you want to create.

Let’s say, for example, you need to create a bean that requires a custom configuration, and this configuration needs to be loaded from a file. You can create a CDI producer to create this bean using the following code snippet:

public class CustomConfig {
  private String configValue;

  public CustomConfig(String configValue) {
    this.configValue = configValue;
  }

  public String getConfigValue() {
    return configValue;
  }
}

public class CustomConfigProducer {

  @Produces
  public CustomConfig createCustomConfig() {
    String configValue = readConfigFromFile();
    return new CustomConfig(configValue);
  }

  private String readConfigFromFile() {
    // code to read config value from file
  }
}

As you can see, the CustomConfigProducer class contains a method annotated with @Produces, which returns an instance of the CustomConfig bean. This method includes the custom logic to read the configuration from a file and initialize the CustomConfig object with the configuration value.

When the container encounters an injection point for the CustomConfig bean, it will look for a CDI producer that can create the bean. It will then invoke the createCustomConfig() method to create the instance.

Now, mateys, you know how to use CDI producers to create custom beans to fit your needs. With this knowledge, you can set sail on your coding journey with confidence, knowing that you can create beans that are tailored to your specific requirements.

May your beans be ever customized and your code be always seaworthy!