Java Platform, Enterprise Edition (Java EE) 8 The Java EE Tutorial

## The compositecomponentexample Example Application

The `compositecomponentexample` application creates a composite component that accepts a name (or any other string). The component interacts with a managed bean that calculates whether the letters in the name, if converted to numeric values, add up to a prime number. The component displays the sum of the letter values and reports whether it is or is not prime.

The `compositecomponentexample` application has a composite component file, a using page, and a managed bean.

The source code for this application is in the tut-install`/examples/web/jsf/compositecomponentexample/` directory.

The following topics are addressed here:

- The Composite Component File

- The Using Page

- The Managed Bean

- Running the compositecomponentexample Example

### The Composite Component File

The composite component file is an XHTML file, `/web/resources/ezcomp/PrimePanel.xhtml`. It has a `composite:interface` section that declares the labels for the name and a command button. It also declares a managed bean, which defines properties for the name.

    <composite:interface>
        <composite:attribute name="namePrompt"
                             default="Name, word, or phrase: "/>
        <composite:attribute name="calcButtonText" default="Calculate"/>
        <composite:attribute name="calcAction"
                             method-signature="java.lang.String action()"/>
        <composite:attribute name="primeBean"/>
        <composite:editableValueHolder name="nameVal" targets="form:name"/>
    </composite:interface>

The composite component implementation accepts the input value for the `name` property of the managed bean. The `h:outputStylesheet` tag specifies the stylesheet as a relocatable resource. The implementation then specifies the format of the output, using properties of the managed bean, as well as the format of error messages. The sum value is rendered only after it has been calculated, and the report of whether the sum is prime or not is rendered only if the input value is validated.

    <composite:implementation>
        <h:form id="form">
            <h:outputStylesheet library="css" name="default.css"
                                target="head"/>
            <h:panelGrid columns="2" role="presentation">
                <h:outputLabel for="name"
                               value="#{cc.attrs.namePrompt}"/>
                <h:inputText id="name"
                             size="45"
                             value="#{cc.attrs.primeBean.name}"
                             required="true"/>
            </h:panelGrid>
            <p>
                <h:commandButton id="calcButton"
                                 value="#{cc.attrs.calcButtonText}"
                                 action="#{cc.attrs.calcAction}">
                    <f:ajax execute="name" render="outputGroup"/>
                </h:commandButton>
            </p>

           <h:panelGroup id="outputGroup" layout="block">
                <p>
                    <h:outputText id="result" style="color:blue"
                                  rendered="#{cc.attrs.primeBean.totalSum gt 0}"
                                  value="Sum is #{cc.attrs.primeBean.totalSum}" />
                </p>
                <p>
                    <h:outputText id="response" style="color:blue"
                                  value="#{cc.attrs.primeBean.response}"
                                  rendered="#{!facesContext.validationFailed}"/>
                    <h:message id="errors1"
                               showSummary="true"
                               showDetail="false"
                               style="color: #d20005;
                               font-family: 'New Century Schoolbook', serif;
                               font-style: oblique;
                               text-decoration: overline"
                               for="name"/>
                </p>
            </h:panelGroup>
        </h:form>
    </composite:implementation>

### The Using Page

The using page in this example application, `web/index.xhtml`, is an XHTML file that invokes the `PrimePanel.xhtml` composite component file along with the managed bean. It validates the user’s input.

    <div id="compositecomponent">
        <ez:PrimePanel primeBean="#{primeBean}"
                       calcAction="#{primeBean.calculate}">
        </ez:PrimePanel>
    </div>

### The Managed Bean

The managed bean, `PrimeBean.java`, defines a method called `calculate`, which performs the calculations on the input string and sets properties accordingly. The bean first creates an array of prime numbers. It calculates the sum of the letters in the string, with `'a'` equal to 1 and `'z'` equal to 26, and determines whether the value can be found in the array of primes. An uppercase letter in the input string has the same value as its lowercase equivalent.

The bean specifies the minimum and maximum size of the `name` string, which is enforced by the Bean Validation `@Size` constraint. The bean uses the `@Model` annotation, a shortcut for `@Named` and `@RequestScoped`, as described in Step 7 of To View the hello1 Web Module Using NetBeans IDE.

    @Model
    public class PrimeBean implements Serializable {
        ...
        @Size(min=1, max=45)
        private String name;
        ...

        public String calculate() {
            ...
        }
    }

### Running the compositecomponentexample Example

You can use either NetBeans IDE or Maven to build, package, deploy, and run the `compositecomponentexample` example.

The following topics are addressed here:

- To Build, Package, and Deploy the compositecomponentexample Example Using NetBeans IDE

- To Build, Package, and Deploy the compositecomponentexample Example Using Maven

- To Run the compositecomponentexample Example

#### To Build, Package, and Deploy the compositecomponentexample Example Using NetBeans IDE

1. Make sure that GlassFish Server has been started (see Starting and Stopping GlassFish Server).

2. From the File menu, choose Open Project.

3. In the Open Project dialog box, navigate to:

       tut-install/examples/web/jsf

4. Select the `compositecomponentexample` folder.

5. Click Open Project.

6. In the Projects tab, right-click the `compositecomponentexample` project and select Build.

   This command builds and deploys the application.

#### To Build, Package, and Deploy the compositecomponentexample Example Using Maven

1. Make sure that GlassFish Server has been started (see Starting and Stopping GlassFish Server).

2. In a terminal window, go to:

       tut-install/examples/web/jsf/compositecomponentexample/

3. Enter the following command to build and deploy the application:

       mvn install

#### To Run the compositecomponentexample Example

1. In a web browser, enter the following URL:

       http://localhost:8080/compositecomponentexample

2. On the page that appears, enter a string in the Name, word, or phrase field, then click Calculate.

   The page reports the sum of the letters and whether the sum is prime. A validation error is reported if no value is entered or if the string contains more than 45 characters.

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