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Java Platform, Enterprise Edition (Java EE) 8 The Java EE Tutorial |
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The main interface allows students and staff to check students in and out, and record when students are outside at the playground.
The following topics are addressed here:
The following entities used in the main interface encapsulate data
stored and manipulated by Duke’s Tutoring, and are located in the
dukestutoring.entity package in the dukes-tutoring-common project.
Person: The Person entity defines attributes common to students
and guardians tracked by the application. These attributes are the
person’s name and contact information, including phone numbers and email
address. This entity has two subclasses, Student and Guardian.
PersonDetails: The PersonDetails entity is used to store
additional data common to all people, such as attributes like pictures
and the person’s birthday, which aren’t included in the Person entity
for performance reasons.
Student and Guardian: The Student entity stores attributes
specific to the students who come to tutoring. This includes information
like the student’s grade level and school. The Guardian entity’s
attributes are specific to the parents or guardians of a Student.
Students and guardians have a many-to-many relationship. That is, a
student may have one or more guardians, and a guardian may have one or
more students.
Address: The Address entity represents a mailing address and is
associated with Person entities. Addresses and people have a
many-to-one relationship. That is, one person may have many addresses.
TutoringSession: The TutoringSession entity represents a
particular day at the tutoring center. A particular tutoring session
tracks which students attended that day, and which students went to the
park.
StatusEntry: The StatusEntry entity, which logs when a student’s
status changes, is associated with the TutoringSession entity.
Students' statuses change when they check in to a tutoring session, when
they go to the park, and when they check out. The status entry allows
the tutoring center staff to track exactly which students attended a
tutoring session, when they checked in and out, which students went to
the park while they were at the tutoring center, and when they went to
and came back from the park.
For information on creating Java Persistence API entities, see Chapter 40, "Introduction to the Java Persistence API." For information on validating entity data, see Validating Persistent Fields and Properties and Chapter 24, "Bean Validation: Advanced Topics."
The following enterprise beans used in the main interface provide the
business logic for Duke’s Tutoring, and are located in the
dukestutoring.ejb package in the dukes-tutoring-war project:
ConfigBean is a singleton session bean used to create the default
students when the application is initially deployed, and to create an
automatic EJB timer that creates tutoring session entities every
weekday.
RequestBean is a stateless session bean containing the business
methods for the main interface. The bean also has business methods for
retrieving lists of students. These business methods use strongly typed
Criteria API queries to retrieve data from the database. RequestBean
also injects a CDI event instance, StatusEvent. This event is fired
from the business methods when the status of a student changes.
For information on creating and using enterprise beans, see Enterprise Beans. For information on creating strongly typed Criteria API queries, see Chapter 43, "Using the Criteria API to Create Queries." For information on CDI events, see Using Events in CDI Applications.
The javaeetutorial.dukestutoring.web.websocket.StatusEndpoint class is
a WebSocket server endpoint that returns students and their status to
client endpoints. The StatusEndpoint.updateStatus method is a CDI
observer method for the StatusEvent event. When a student’s status
changes in the main interface, a StatusEvent is fired. The
updateStatus observer method is called by the container, and pushes
out the status change to all the client endpoints registered with
StatusEndpoint.
The index.xhtml JavaServer Faces page contains JavaScript code to
connect to the WebSocket endpoint. The onMessage method on this page
clicks a JavaServer Faces button, which makes an Ajax request to refresh
the table that shows the current status of the students.
For more information on WebSocket endpoints, see Chapter 19, "Java API for WebSocket." For information on CDI events, see Using Events in CDI Applications.
The Duke’s Tutoring application uses Facelets to display the user
interface, making extensive use of the templating features of Facelets.
Facelets, the default display technology for JavaServer Faces
technology, consists of XHTML files located in the
_tut-install_/examples/case-studies/dukes-tutoring-war/src/main/webapp/
directory.
The following Facelets files are used in the main interface:
template.xhtml: Template file for the main interface
error.xhtml: Error file if something goes wrong
index.xhtml: Landing page for the main interface
park.xhtml: Page showing who is currently at the park
current.xhtml: Page showing who is currently in today’s tutoring
session
statusEntries.xhtml: Page showing the detailed status entry log for
today’s session
resources/components/allStudentsTable.xhtml: A composite component
for a table displaying all active students
resources/components/allInactiveStudentsTable.xhtml: A composite
component for a table displaying all inactive students
resources/components/currentSessionTable.xhtml: A composite
component for a table displaying all students in today’s session
resources/components/parkTable.xhtml: A composite component for a
table displaying all students currently at the park
WEB-INF/includes/mainNav.xhtml: XHTML fragment for the main
interface’s navigation bar
For information on using Facelets, see Chapter 8, "Introduction to Facelets."
The following helper classes, found in the dukes-tutoring-common
project’s dukestutoring.util package, are used in the main interface.
CalendarUtil: A class that provides a method to strip the
unnecessary time data from java.util.Calendar instances.
Email: A custom Bean Validation annotation class for validating
email addresses in the Person entity.
StatusType: An enumerated type defining the different statuses that
a student can have. Possible values are IN, OUT, and PARK.
StatusType is used throughout the application, including in the
StatusEntry entity, and throughout the main interface. StatusType
also defines a toString method that returns a localized translation of
the status based on the locale.
The strings used in the main interface are encapsulated into resource
bundles to allow the display of localized strings in multiple locales.
Each of the properties files has locale-specific files appended with
locale codes, containing the translated strings for each locale. For
example, Messages_es.properties contains the localized strings for
Spanish locales.
The dukes-tutoring-common project has the following resource bundle
under src/main/resources/.
javaeetutorial/dukestutoring/util/StatusMessages.properties: Strings
for each of the status types defined in the StatusType enumerated type
for the default locale. Each supported locale has a property file of the
form StatusMessages_`locale prefix.properties` containing the
localized strings. For example, the strings for Spanish-speaking locales
are located in StatusMessages_es.properties.
The dukes-tutoring-war project has the following resource bundles
under src/main/resources/.
ValidationMessages.properties: Strings for the default locale used
by the Bean Validation runtime to display validation messages. This file
must be named ValidationMessages.properties and located in the default
package as required by the Bean Validation specification. Each supported
locale has a property file of the form ValidationMessages_`locale
prefix.properties` containing the localized strings. For example, the
strings for German-speaking locales are located in
ValidationMessages_de.properties.
javaeetutorial/dukestutoring/web/messages/Messages.properties:
Strings for the default locale for the main and administration Facelets
interface. Each supported locale has a property file of the form
Messages_`locale prefix.properties` containing the localized strings.
For example, the strings for simplified Chinese-speaking locales are
located in Messages_zh.properties.
For information on localizing web applications, see Registering Application Messages.
Duke’s Tutoring uses these deployment descriptors in the
src/main/webapp/WEB-INF directory of the dukes-tutoring-war project:
faces-config.xml: The JavaServer Faces configuration file
glassfish-web.xml: The configuration file specific to GlassFish
Server, which defines security role mapping
web.xml: The web application configuration file
Duke’s Tutoring also uses the following deployment descriptor in the
src/main/resources/META-INF directory of the dukes-tutoring-common
project:
persistence.xml: The Java Persistence API configuration file
No enterprise bean deployment descriptor is used in Duke’s Tutoring. Annotations in the enterprise bean class files are used for the configuration of enterprise beans in this application.
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