Components of the rsvp Example Application

The three enterprise beans in the rsvp example application are rsvp.ejb.ConfigBean, rsvp.ejb.StatusBean, and rsvp.ejb.ResponseBean.

ConfigBean is a singleton session bean that initializes the data in the database.

StatusBean exposes a JAX-RS resource for displaying the current status of all invitees to an event. The URI path template is declared as follows:

@Path("/status/{eventId}/"}

The URI path variable eventId is a @PathParam variable in the getResponse method, which responds to HTTP GET requests and has been annotated with @GET. The eventId variable is used to look up all the current responses in the database for that particular event.

ResponseBean exposes a JAX-RS resource for setting an invitee's response to a particular event. The URI path template for ResponseBean is declared as follows:

@Path("/{eventId}/{inviteId}

Two URI path variables are declared in the path template: eventId and inviteId. As in StatusBean, eventId is the unique ID for a particular event. Each invitee to that event has a unique ID for the invitation, and that is the inviteId. Both of these path variables are used in two JAX-RS methods in ResponseBean: getResponse and putResponse. The getResponse method responds to HTTP GET requests and displays the invitee's current response and a form to change the response.

An invitee who wants to change his or her response selects the new response and submits the form data, which is processed as an HTTP PUT request by the putResponse method. One of the parameters to the putResponse method, the userResponse string, is annotated with @FormParam("attendeeResponse"). The HTML form created by getResponse stores the changed response in the select list with an ID of attendeeResponse. The annotation @FormParam("attendeeResponse") indicates that the value of the select response is extracted from the HTTP PUT request and stored as the userResponse string. The putResponse method uses userResponse, eventId, and inviteId to update the invitee's response in the database.

The events, people, and responses in rsvp are encapsulated in Java Persistence API entities. The rsvp.entity.Event, rsvp.entity.Person, and rsvp.entity.Response entities respectively represent events, invitees, and responses to an event.

The rsvp.util.ResponseEnum class declares an enumerated type that represents all the possible response statuses an invitee may have.