test

Your First Cup: An Introduction to the Java EE Platform

The Facelets Web Interface

The firstcup web application interface has two XHTML files. The greeting.xhtml file displays Duke's current age and the form to the user for her to enter her birthday. The response.xhtml file displays the age difference between the user and Duke.

The greeting.xhtml contains several pieces of the firstcup application detailed previously. It uses the localized strings contained in WebMessages.properties and WebMessages_es.properties. It uses the DukesBDay managed bean to call both the DukesAgeResource JAX-RS web service and the DukesBirthdayBean enterprise bean. It uses the inputDate composite component to create the input for the user to enter her birthday.

Example 3–4 The greeting.xhtml File

Here's the content of the greeting.xhtml file.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html
      PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
      "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"
      xmlns:f="http://java.sun.com/jsf/core"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:fc="http://java.sun.com/jsf/composite/components">
<head>
    <title>Firstcup Greeting Page</title>
</head>
<body>
<h:form>
    <h2>
        <h:outputText value="#{bundle.Welcome}"/>
    </h2>
    <h:outputText value="#{bundle.DukeIs} "/>
    <h:outputText value="#{DukesBDay.age} #{bundle.YearsOldToday}"/>
    <p/>
    <h:outputText value="#{bundle.Instructions}"/>
    <p/>
    <h:outputText value="#{bundle.YourBD} "/>
    <fc:inputDate id="userBirthday" date="#{DukesBDay.yourBD}" />
    <h:outputText value=" #{bundle.Pattern}"/>
    <p/>
    <h:commandButton value="#{bundle.Submit}" action="response"/>
    <p/>
    <h:message for="userBirthday" style="color:red"/>
</h:form>
</body>
</html>

The greeting.xhtml file uses the JSF Core, HTML Render Kit, and the components resource library tag libraries. The components tag library has a prefix of fc, and is used to specify the inputDate composite component in the form below. The <fc:inputDate id="userBirthday" date="#{DukesBDay.yourBD}" /> tag has the required date attribute, and stores the value in the yourBD property in the DukesBDay managed bean by using the EL expression #{DukesBDay.yourBD}.

The localized strings are referred to by using the EL expressions #{bundle.property name}. For example, the <h:outputText value="#{bundle.Welcome}"/> tag will display the following string in English locales:


Hi. I'm Duke. Let's find out who's older -- You or I.

The <h:commandButton value="#{bundle.Submit}" action="response"/> tag creates a submit button and specifies that a successful submission should render the response.xhtml file by setting the action attribute to response. The action attribute is used to define navigation rules for forms in Facelets pages.

If the form submission is unsuccessful, a warning message is displayed. This is done with the <h:message for="userBirthday" style="color:red"/> tag, which is connected to the inputDate composite component with the id userBirthday. That is, if there's an error with the input of the inputDate component, a warning message is displayed.

The response.xhtml displays the age difference between the user and Duke. Different strings are displayed based on whether the user is the same age, younger, or older than duke. The text can be displayed or not based on the conditions specified by the rendered attribute of the <h:outputText> tag. The conditions used in the rendered attribute are EL language alternatives to the Java programming language conditional operators to allow XML parsing of the XHTML file.

Table 3–1 Conditional Operator EL Language Alternatives

Logical Condition 

Java Programming Language Conditional Operator 

EL Language Alternative 

AND 

&&

&&

EQUALS 

==

==

LESS THAN 

<

lt

GREATER THAN 

>

gt

Example 3–5 The response.xhtml File

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html
      PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
      "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"
      xmlns:f="http://java.sun.com/jsf/core"
      xmlns:h="http://java.sun.com/jsf/html">
<head>
    <title>Response Page</title>
</head>
<body>
<h:form>
    <h:outputText value="#{bundle.YouAre} "/>
    <h:outputText value="#{bundle.SameAge}"
                  rendered="#{DukesBDay.ageDiff == 0}"/>
    <h:outputText value="#{DukesBDay.absAgeDiff}"
                  rendered="#{DukesBDay.ageDiff lt 0}"/>
    <h:outputText value=" #{bundle.Year} "
                  rendered="#{DukesBDay.ageDiff == -1}"/>
    <h:outputText value=" #{bundle.Years} "
                  rendered="#{DukesBDay.ageDiff lt -1}"/>
    <h:outputText value="#{bundle.Younger}"
                  rendered="#{DukesBDay.ageDiff lt 0}"/>
    <h:outputText value="#{DukesBDay.absAgeDiff}"
                  rendered="#{DukesBDay.ageDiff gt 0}"/>
    <h:outputText value=" #{bundle.Year} "
                  rendered="#{DukesBDay.ageDiff == 1}"/>
    <h:outputText value=" #{bundle.Years} "
                  rendered="#{DukesBDay.ageDiff gt 1}"/>
    <h:outputText value="#{bundle.Older}" rendered="#{DukesBDay.ageDiff gt 0}"/>    <p/>
    <h:commandButton id="back" value="#{bundle.Back}" action="greeting"/>
</h:form>
</body>
</html>

For example, the #{bundle.SameAge} string is displayed if the user and Duke have the same birthday as specified by the condition #{DukesBDay.ageDiff == 0} in the rendered attribute. That is, display the following string if the ageDiff property of DukesBDay equals 0:


You are the same age as Duke!

The form also contains a <h:commandButton> tag that creates a back button that will direct the user back to the greeting.xhtml page, as specified in the action attribute.