Package com.broadleafcommerce.common.messaging

Interface PersistenceHandler

  • public interface PersistenceHandler
    PersistenceHandlers are responsible for listening for PersistenceConsumer channel events associated with a specific repository domain type. These events are emitted in response to persistence state change for entities and are delivered in the form of a JSON representation of the latest state of the entity.

    Generally, concrete implementations take a form similar to this. 

     public class TestPersistenceHandler implements PersistenceHandler {

   @Override
   public void processStateChange(String entityJson) {
       //do something interesting in reaction to the state change
   }

 }

    Implementations of this interface assumes that you have @EnableBinding(Persistence.class) in an @Configuration class within your application that activates the channel bindings that the handle(String) method relies on.

    Author:
    Jeff Fischer

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static org.slf4j.Logger log  

    • Method Summary

      All Methods Instance Methods Abstract Methods Default Methods 
      Modifier and Type Method Description
      com.fasterxml.jackson.databind.ObjectMapper getObjectMapper()
      Return the ObjectMapper to use when handling the message json.
      String[] getSupportedSimpleTypeNames()
      The simple entity type names supported by this service.
      default void handle​(String entityJson)
      Entry point for the handler.
      void hook​(String entityJson)
      Hook point for message listeners to bind to the input channel with @StreamListener.
      default boolean isValidType​(String reportedType, String projectionType)
      Determine if the type (i.e.
      void processStateChange​(com.fasterxml.jackson.databind.JsonNode entityJson)
      Handle the entityJson representation of the change that has been deemed appropriate for this handler based on comparing the expected _class parameter in the JSON against the generic type of the handler implementation.
      default void validate​(com.fasterxml.jackson.databind.JsonNode entityJson)
      Verify the signed JWT token and validate the user claims (especially authorities) against the consumption functionality.

    • Field Detail

      • log

        static final org.slf4j.Logger log

    • Method Detail

      • hook

        void hook​(String entityJson)
        Hook point for message listeners to bind to the input channel with @StreamListener. Implementations of this method generally delegate to handle(String). It is generally important that each input channel name is unique in order to guarantee other listeners will still process the persistence message, even if one or more other listeners throw exceptions. As a corollary, there will also generally be a unique @Input annotated SubscribableChannel instance per listener tied to the unique input channel.
        Parameters:
        entityJson - The JSON representation of the changed entity state coming in from the input channel

      • handle

        default void handle​(String entityJson)
        Entry point for the handler. This method will review the entity json representation and evaluate suitability against the getSupportedSimpleTypeNames() types. If appropriate, processStateChange(JsonNode) is called.
        Parameters:
        entityJson - The JSON representation of the changed entity state

      • isValidType

        default boolean isValidType​(String reportedType,
                            @Nullable
                            String projectionType)
        Determine if the type (i.e. simple class name of the entity) of the incoming entity persistence message is appropriate for this handler.
        Parameters:
        reportedType - The type of the incoming entity persistence message
        projectionType - Optional. The projected domain type, if applicable. This is generally derived from entity types that advertise their projection type during JSON serialization.
        Returns:
        Whether or not the type is supported

      • getObjectMapper

        com.fasterxml.jackson.databind.ObjectMapper getObjectMapper()
        Return the ObjectMapper to use when handling the message json. Typically, this would utilize an autowired bean instance.
        Returns:
        the ObjectMapper to use when handling the message json

      • processStateChange

        void processStateChange​(com.fasterxml.jackson.databind.JsonNode entityJson)
        Handle the entityJson representation of the change that has been deemed appropriate for this handler based on comparing the expected _class parameter in the JSON against the generic type of the handler implementation.
        Parameters:
        entityJson - The JSON representing the last known state of the entity

      • getSupportedSimpleTypeNames

        String[] getSupportedSimpleTypeNames()
        The simple entity type names supported by this service. This is not the fully qualified classname, rather the simple name - similar to what is returned by Class.getSimpleName().
        Returns:
        The array of simple type names supported by this handler

      • validate

        default void validate​(com.fasterxml.jackson.databind.JsonNode entityJson)
        Verify the signed JWT token and validate the user claims (especially authorities) against the consumption functionality. Generally, throw an IllegalArgumentException if the claims made in the JWT are deemed incorrect or inappropriate for the desired task.
        Parameters:
        entityJson - Message instance capable of supplying a signed JWT token