In this article by Mert Çalışkan and Oleg Varaksin, author of PrimeFaces Cookbook – Second Edition, we will cover the following recipes:
- Setting up and configuring the PrimeFaces library
- AJAX basics with process and update
- PrimeFaces selectors
- Internationalization (i18n) and Localization (L10n)
This article will provide details on the setup and configuration of PrimeFaces, along with the basics of the PrimeFaces AJAX mechanism. The goal of this article is to provide a sneak preview of some of the features of PrimeFaces, such as the AJAX processing mechanism and Internationalization, and Localization.
(For more resources related to this topic, see here.)
Setting up and configuring the PrimeFaces library
PrimeFaces is a lightweight JSF component library with one JAR file, which needs no configuration and does not contain any required external dependencies. To start with the development of the library, all we need is the artifact for the library.
Getting ready
You can download the PrimeFaces library from http://primefaces.org/downloads.html, and you need to add the primefaces-{version}.jar file to your classpath. After that, all you need to do is import the namespace of the library that is necessary to add the PrimeFaces components to your pages to get started.
If you are using Maven (for more information on installing Maven, please visit http://maven.apache.org/guides/getting-started/maven-in-five-minutes.html), you can retrieve the PrimeFaces library by defining the Maven repository in your Project Object Model XML file, pom.xml, as follows:
<repository> <id>prime-repo</id> <name>PrimeFaces Maven Repository</name> <url>http://repository.primefaces.org</url> </repository>
Add the dependency configuration as follows:
<dependency> <groupId>org.primefaces</groupId> <artifactId>primefaces</artifactId> <version>5.2</version> </dependency>
At the time of writing this article, the latest and most stable version of PrimeFaces was 5.2. To check whether this is the latest available version or not, please visit http://primefaces.org/downloads.html. The code in this article will work properly with PrimeFaces 5.2. In prior versions or the future versions, some methods, attributes, or components’ behaviors may change.
How to do it…
In order to use PrimeFaces components, first we need to add the namespace declaration to our pages. The namespace for PrimeFaces components is as follows:
That is all there is to it. Note that the p prefix is just a symbolic link, and any other character can be used to define the PrimeFaces components. Now you can create your first XHTML page with a PrimeFaces component, as shown in the following code snippet:
<html
>
<f:view contentType=”text/html”>
<h:head />
<h:body>
<h:form>
<p:spinner />
</h:form>
</h:body>
</f:view>
</html>
This will render a spinner component with an empty value, as shown in the following screenshot:
A link to the working example for the given page is given at the end of this recipe.
How it works…
When the page is requested, the p:spinner component is rendered with the SpinnerRenderer class implemented by the PrimeFaces library. Since the spinner component is an input component, the request-processing life cycle will get executed when the user inputs data and performs a post back on the page.
For the first page, we also needed to provide the contentType parameter for f:view since WebKit-based browsers, such as Google Chrome and Safari, request for the content type application/xhtml+xml by default. This would overcome unexpected layout and styling issues that might occur.
There’s more…
PrimeFaces only requires a Java 5+ runtime and a JSF 2.x implementation as mandatory dependencies. There are some optional libraries for certain features. All of these are listed in this table:
| Dependency | Version | Type | Description |
| JSF runtime | 2.0, 2.1, or 2.2 | Required | Apache MyFaces or Oracle Mojarra |
| itext | 2.1.7 | Optional | DataExporter (PDF) |
| apache-poi | 3.7 | Optional | DataExporter (Excel) |
| rome | 1.0 | Optional | FeedReader |
| commons-fileupload | 1.3 | Optional | FileUpload |
| commons-io | 2.2 | Optional | FileUpload |
| atmosphere | 2.2.2 | Optional | PrimeFaces Push |
| barcode4j-light | 2.1 | Optional | Barcode Generation |
| qrgen | 1.4 | Optional | QR code support for barcode |
| hazelcast | 2.6.5+ | Optional | Integration of the <p:cache> component with hazelcast |
| ehcache | 2.7.4+ | Optional | Integration of the <p:cache> component with ehcache |
Please ensure that you have only one JAR file of PrimeFaces or a specific PrimeFaces theme in your classpath in order to avoid any issues regarding resource rendering.
Currently, PrimeFaces fully supports nonlegacy web browsers with Internet Explorer 10, Safari, Firefox, Chrome, and Opera.
The PrimeFaces Cookbook Showcase application
This recipe is available in the demo web application on GitHub (https://github.com/ova2/primefaces-cookbook/tree/second-edition). Clone the project if you have not done it yet, explore the project structure, and build and deploy the WAR file on application servers compatible with Servlet 3.x, such as JBoss WildFly and Apache TomEE.
The showcase for the recipe is available under http://localhost:8080/pf-cookbook/views/chapter1/yourFirstPage.jsf.
AJAX basics with process and update
PrimeFaces provides Partial Page Rendering (PPR) and the view-processing feature based on standard JSF 2 APIs to enable choosing what to process in the JSF life cycle and what to render in the end with AJAX. PrimeFaces AJAX Framework is based on standard server-side APIs of JSF 2. On the client side, rather than using the client-side API implementations of JSF, such as Mojarra or MyFaces, PrimeFaces scripts are based on the jQuery JavaScript library, which is well tested and widely adopted.
How to do it…
We can create a simple page with a command button to update a string property with the current time in milliseconds that is created on the server side and output text to show the value of that string property, as follows:
<p:commandButton update="display"
action="#{basicPPRBean.updateValue}" value="Update" />
<h:outputText id="display" value="#{basicPPRBean.value}"/>
If we want to update multiple components with the same trigger mechanism, we can provide the ID’s of the components to the update attribute by providing them with a space, comma, or both, as follows:
<p:commandButton update="display1,display2" /> <p:commandButton update="display1 display2" /> <p:commandButton update="display1,display2 display3" />
In addition, there are reserved keywords that are used for a partial update. We can also make use of these keywords along with the ID’s of the components, as described in the following table. Some of them come with the JSF standard, and PrimeFaces extends this list with custom keywords. Here’s the table we talked about:
| Keyword | JSF/PrimeFaces | Description |
| @this | JSF | The component that triggers the PPR is updated |
| @form | JSF | The encapsulating form of the PPR trigger is updated |
| @none | JSF | PPR does not change the DOM with an AJAX response |
| @all | JSF | The whole document is updated as in non-AJAX requests |
| @parent | PrimeFaces | The parent of the PPR trigger is updated |
| @composite | PrimeFaces | This is the closest composite component ancestor |
| @namingcontainer | PrimeFaces | This is the closest naming container ancestor of the current component |
| @next | PrimeFaces | This is the next sibling |
| @previous | PrimeFaces | This is the previous sibling |
| @child(n) | PrimeFaces | This is the nth child |
| @widgetVar(name) | PrimeFaces | This is a component stated with a given widget variable name |
The keywords are a server-side part of the PrimeFaces Search Expression Framework (SEF), which provides both server-side and client-side extensions to make it easier to reference components. We can also update a component that resides in a different naming container from the component that triggers the update. In order to achieve this, we need to specify the absolute component identifier of the component that needs to be updated. An example of this could be the following:
<h:form id="form1">
<p:commandButton update=":form2:display"
action="#{basicPPRBean.updateValue}" value="Update"/>
</h:form>
<h:form id="form2">
<h:outputText id="display" value="#{basicPPRBean.value}"/>
</h:form>
@Named
@ViewScoped
public class BasicPPRBean implements Serializable {
private String value;
public String updateValue() {
value = String.valueOf(System.currentTimeMillis());
return null;
}
// getter / setter
}
PrimeFaces also provides partial processing, which executes the JSF life cycle phases—apply request values, process validations, update model, and invoke application—for determined components with the process attribute. This provides the ability to do group validation on the JSF pages easily. Mostly group validation needs arise in situations where different values need to be validated in the same form, depending on an action that gets executed. By grouping components for validation, errors that would arise from other components when the page has been submitted can be overcome easily. Components such as commandButton, commandLink, autoComplete, fileUpload, and many others provide this attribute to process partially instead of processing the whole view.
Partial processing could become very handy in cases where a drop-down list needs to be populated upon a selection on another dropdown and where there is an input field on the page with the required attribute set to true. This approach also makes immediate subforms and regions obsolete. It will also prevent submission of the whole page; thus, this will result in lightweight requests. Without partially processing the view for the dropdowns, a selection on one of the dropdowns will result in a validation error on the required field. A working example for this is shown in the following code snippet:
<h:outputText value="Country: " />
<h:selectOneMenu id="countries" value="#{partialProcessing
Bean.country}">
<f:selectItems value="#{partialProcessingBean.countries}" />
<p:ajax listener= "#{partialProcessingBean.handleCountryChange}"
event="change" update="cities" process="@this"/>
</h:selectOneMenu>
<h:outputText value="City: " />
<h:selectOneMenu id="cities" value="#{partialProcessingBean.city}">
<f:selectItems value="#{partialProcessingBean.cities}" />
</h:selectOneMenu>
<h:outputText value="Email: " />
<h:inputText value="#{partialProcessingBean.email}"
required="true" />
With this partial processing mechanism, when a user changes the country, the cities of that country will be populated in the dropdown regardless of whether any input exists for the email field or not.
How it works…
As illustrated in the partial processing example to update a component in a different naming container, <p:commandButton> is updating the <h:outputText> component that has the display ID and the :form2:display absolute client ID, which is the search expression for the findComponent method. An absolute client ID starts with the separator character of the naming container, which is : by default.
The <h:form>, <h:dataTable>, and composite JSF components, along with <p:tabView>, <p:accordionPanel>, <p:dataTable>, <p:dataGrid>, <p:dataList>, <p:carousel>, <p:galleria>, <p:ring>, <p:sheet>, and <p:subTable> are the components that implement the NamingContainer interface. The findComponent method, which is described at http://docs.oracle.com/javaee/7/api/javax/faces/component/UIComponent.html, is used by both JSF core implementation and PrimeFaces.
There’s more…
JSF uses : (colon) as the separator for the NamingContainer interface. The client IDs that will be rendered in the source page will be of the kind id1:id2:id3. If needed, the configuration of the separator can be changed for the web application to something other than the colon with a context parameter in the web.xml file of the web application, as follows:
<context-param> <param-name>javax.faces.SEPARATOR_CHAR</param-name> <param-value>_</param-value> </context-param>
It’s also possible to escape the : character, if needed, in the CSS files with the character, as :. The problem that might occur with the colon is that it’s a reserved keyword for the CSS and JavaScript frameworks, like jQuery, so it might need to be escaped.
The PrimeFaces Cookbook Showcase application
This recipe is available in the demo web application on GitHub (https://github.com/ova2/primefaces-cookbook/tree/second-edition). Clone the project if you have not done it yet, explore the project structure, and build and deploy the WAR file on application servers compatible with Servlet 3.x, such as JBoss WildFly and Apache TomEE.
For the demos of this recipe, refer to the following:
- Basic Partial Page Rendering is available at http://localhost:8080/pf-cookbook/views/chapter1/basicPPR.jsf
- Updating Component in a Different Naming Container is available at http://localhost:8080/pf-cookbook/views/chapter1/componentInDifferentNamingContainer.jsf
- An example of Partial Processing is available at http://localhost:8080/pf-cookbook/views/chapter1/partialProcessing.jsf
PrimeFaces selectors
PrimeFaces integrates the jQuery Selector API (http://api.jquery.com/category/selectors) with the JSF component-referencing model. Partial processing and updating of the JSF components can be done using the jQuery Selector API instead of a regular server-side approach with findComponent(). This feature is called the PrimeFaces Selector (PFS) API. PFS provides an alternative, flexible approach to reference components to be processed or updated partially. PFS is a client-side part of the PrimeFaces SEF, which provides both server-side and client-side extensions to make it easier to reference components.
In comparison with regular referencing, there is less CPU server load because the JSF component tree is not traversed on the server side in order to find client IDs. PFS is implemented on the client side by looking at the DOM tree. Another advantage is avoiding container limitations, and thus the cannot find component exception—since the component we were looking for was in a different naming container.
The essential advantage of this feature, however, is speed. If we reference a component by an ID, jQuery uses document.getElementById(), a native browser call behind the scene. This is a very fast call, much faster than that on the server side with findComponent(). The second use case, where selectors are faster, is when we have a lot of components with the rendered attributes set to true or false. The JSF component tree is very big in this case, and the findComponent() call is time consuming. On the client side, only the visible part of the component tree is rendered as markup. The DOM is smaller than the component tree and its selectors work faster.
In this recipe, we will learn PFS in detail. PFS is recognized when we use @(…) in the process or update attribute of AJAX-ified components. We will use this syntax in four command buttons to reference the parts of the page we are interested in.
How to do it…
The following code snippet contains two p:panel tags with the input, select, and checkbox components respectively. The first p:commandButton component processes/updates all components in the form(s). The second one processes / updates all panels. The third one processes input, but not select components, and updates all panels. The last button only processes the checkbox components in the second panel and updates the entire panel.
<p:messages id="messages" autoUpdate="true"/> <p:panel id="panel1" header="First panel"> <h:panelGrid columns="2"> <p:outputLabel for="name" value="Name"/> <p:inputText id="name" required="true"/> <p:outputLabel for="food" value="Favorite food"/> <h:selectOneMenu id="food" required="true"> ... </h:selectOneMenu> <p:outputLabel for="married" value="Married?"/> <p:selectBooleanCheckbox id="married" required="true" label="Married?"> <f:validator validatorId="org.primefaces.cookbook. validator.RequiredCheckboxValidator"/> </p:selectBooleanCheckbox> </h:panelGrid> </p:panel> <p:panel id="panel2" header="Second panel"> <h:panelGrid columns="2"> <p:outputLabel for="address" value="Address"/> <p:inputText id="address" required="true"/> <p:outputLabel for="pet" value="Favorite pet"/> <h:selectOneMenu id="pet" required="true"> ... </h:selectOneMenu> <p:outputLabel for="gender" value="Male?"/> <p:selectBooleanCheckbox id="gender" required="true" label="Male?"> <f:validator validatorId="org.primefaces.cookbook. validator.RequiredCheckboxValidator"/> </p:selectBooleanCheckbox> </h:panelGrid> </p:panel> <h:panelGrid columns="5" style="margin-top:20px;"> <p:commandButton process="@(form)" update="@(form)" value="Process and update all in form"/> <p:commandButton process="@(.ui-panel)" update="@(.ui-panel)" value="Process and update all panels"/> <p:commandButton process="@(.ui-panel :input:not(select))" update="@(.ui-panel)" value="Process inputs except selects in all panels"/> <p:commandButton process="@(#panel2 :checkbox)" update="@(#panel2)" value="Process checkboxes in second panel"/> </h:panelGrid>
In terms of jQuery selectors, regular input field, selection, and checkbox controls are all inputs. They can be selected by the :input selector.
The following screenshot shows what happens when the third button is pushed. The p:inputText and p:selectBooleanCheckbox components are marked as invalid. The h:selectOneMenu component is not marked as invalid although no value was selected by the user.
How it works…
The first selector from the @(form) first button selects all forms on the page. The second selector, @(.ui-panel), selects all panels on the page as every main container of PrimeFaces’ p:panel component has this style class. Component style classes are usually documented in the Skinning section in PrimeFaces User’s Guide (http://www.primefaces.org/documentation.html). The third selector, @(.ui-panel :input:not(select)), only selects p:inputText and p:selectBooleanCheckbox within p:panel. This is why h:selectOneMenu was not marked as invalid in the preceding screenshot. The validation of this component was skipped because it renders itself as an HTML select element. The last selector variant, @(#panel2 :checkbox), intends to select p:selectBooleanCheckbox in the second panel only.
In general, it is recommended that you use Firebug (https://getfirebug.com) or a similar browser add-on to explore the generated HTML structure when using jQuery selectors.
A common use case is skipping validation for the hidden fields. Developers often hide some form components dynamically with JavaScript. Hidden components get validated anyway, and the form validation can fail if the fields are required or have other validation constraints. The first solution would be to disable the components (in addition to hiding them). The values of disabled fields are not sent to the server. The second solution would be to use jQuery’s :visible selector in the process attribute of a command component that submits the form.
There’s more…
PFS can be combined with regular component referencing as well, for example, update=”compId1 :form:compId2 @(.ui-tabs :input)”.
The PrimeFaces Cookbook Showcase application
This recipe is available in the demo web application on GitHub (https://github.com/ova2/primefaces-cookbook/tree/second-edition). Clone the project if you have not done it yet, explore the project structure, and build and deploy the WAR file on application servers compatible with Servlet 3.x, such as JBoss WildFly and Apache TomEE.
The showcase for the recipe is available at http://localhost:8080/pf-cookbook/views/chapter1/pfs.jsf.
Internationalization (i18n) and Localization (L10n)
Internationalization (i18n) and Localization (L10n) are two important features that should be provided in the web application’s world to make it accessible globally.
With Internationalization, we are emphasizing that the web application should support multiple languages, and with Localization, we are stating that the text, date, or other fields should be presented in a form specific to a region.
PrimeFaces only provides English translations. Translations for other languages should be provided explicitly. In the following sections, you will find details on how to achieve this.
Getting ready
For internationalization, first we need to specify the resource bundle definition under the application tag in faces-config.xml, as follows:
<application> <locale-config> <default-locale>en</default-locale> <supported-locale>tr_TR</supported-locale> </locale-config> <resource-bundle> <base-name>messages</base-name> <var>msg</var> </resource-bundle> </application>
A resource bundle is a text file with the .properties suffix that would contain locale-specific messages. So, the preceding definition states that the resource bundle messages_{localekey}.properties file will reside under classpath, and the default value of localekey is en, which stands for English, and the supported locale is tr_TR, which stands for Turkish. For projects structured by Maven, the messages_{localekey}.properties file can be created under the src/main/resources project path. The following image was made in the IntelliJ IDEA:
How to do it…
To showcase Internationalization, we will broadcast an information message via the FacesMessage mechanism that will be displayed in PrimeFaces’ growl component. We need two components—growl itself and a command button—to broadcast the message:
<p:growl id="growl" />
<p:commandButton action="#{localizationBean.addMessage}"
value="Display Message" update="growl" />
The addMessage method of localizationBean is as follows:
public String addMessage() {
addInfoMessage("broadcast.message");
return null;
}
The preceding code uses the addInfoMessage method, which is defined in the static MessageUtil class as follows:
public static void addInfoMessage(String str) {
FacesContext context = FacesContext.getCurrentInstance();
ResourceBundle bundle =
context.getApplication().getResourceBundle(context, "msg");
String message = bundle.getString(str);
FacesContext.getCurrentInstance().addMessage(null,
new FacesMessage(FacesMessage.SEVERITY_INFO, message, ""));
}
Localization of components, such as calendar and schedule, can be achieved by providing the locale attribute. By default, locale information is retrieved from the view’s locale, and it can be overridden by a string locale key or with a java.util.Locale instance.
Components such as calendar and schedule use a shared PrimeFaces.locales property to display labels. As stated before, PrimeFaces only provides English translations, so in order to localize the calendar, we need to put the corresponding locales into a JavaScript file and include the scripting file to the page.
The content for the German locale of the Primefaces.locales property for calendar would be as shown in the following code snippet. For the sake of the recipe, only the German locale definition is given and the Turkish locale definition is omitted; you can find it in the showcase application Here’s the code snippet we talked about:
PrimeFaces.locales['de'] = {
closeText: 'Schließen',
prevText: 'Zurück',
nextText: 'Weiter',
monthNames: ['Januar', 'Februar', 'März', 'April', 'Mai',
'Juni', 'Juli', 'August', 'September', 'Oktober', 'November',
'Dezember'],
monthNamesShort: ['Jan', 'Feb', 'Mär', 'Apr', 'Mai', 'Jun',
'Jul', 'Aug', 'Sep', 'Okt', 'Nov', 'Dez'],
dayNames: ['Sonntag', 'Montag', 'Dienstag', 'Mittwoch',
'Donnerstag', 'Freitag', 'Samstag'],
dayNamesShort: ['Son', 'Mon', 'Die', 'Mit', 'Don', 'Fre',
'Sam'],
dayNamesMin: ['S', 'M', 'D', 'M ', 'D', 'F ', 'S'],
weekHeader: 'Woche',
FirstDay: 1,
isRTL: false,
showMonthAfterYear: false,
yearSuffix: '',
timeOnlyTitle: 'Nur Zeit',
timeText: 'Zeit',
hourText: 'Stunde',
minuteText: 'Minute',
secondText: 'Sekunde',
currentText: 'Aktuelles Datum',
ampm: false,
month: 'Monat',
week: 'Woche',
day: 'Tag',
allDayText: 'Ganzer Tag'
};
The definition of the calendar components both with and without the locale attribute would be as follows:
<p:calendar showButtonPanel="true" navigator="true" mode="inline" id="enCal"/> <p:calendar locale="tr" showButtonPanel="true" navigator="true" mode="inline" id="trCal"/> <p:calendar locale="de" showButtonPanel="true" navigator="true" mode="inline" id="deCal"/>
They will be rendered as follows:
How it works…
For Internationalization of the PrimeFaces message, the addInfoMessage method retrieves the message bundle via the defined msg variable. It then gets the string from the bundle with the given key by invoking the bundle.getString(str) method. Finally, the message is added by creating a new PrimeFaces message with the FacesMessage.SEVERITY_INFO severity level.
There’s more…
For some components, localization could be accomplished by providing labels to the components via attributes, such as with p:selectBooleanButton:
<p:selectBooleanButton
value="#{localizationBean.selectedValue}"
onLabel="#{msg['booleanButton.onLabel']}"
offLabel="#{msg['booleanButton.offLabel']}" />
The msg variable is the resource bundle variable that is defined in the resource bundle definition in the PrimeFaces configuration file. The English version of the bundle key definitions in the messages_en.properties file that resides under the classpath would be as follows:
booleanButton.onLabel=Yes booleanButton.offLabel=No
The PrimeFaces Cookbook Showcase application
This recipe is available in the demo web application on GitHub (https://github.com/ova2/primefaces-cookbook/tree/second-edition). Clone the project if you have not done it yet, explore the project structure, and build and deploy the WAR file on application servers compatible with Servlet 3.x, such as JBoss WildFly and Apache TomEE.
For the demos of this recipe, refer to the following:
- Internationalization is available at http://localhost:8080/pf-cookbook/views/chapter1/internationalization.jsf
- Localization of the calendar component is available at http://localhost:8080/pf-cookbook/views/chapter1/localization.jsf
- Localization with resources is available at http://localhost:8080/pf-cookbook/views/chapter1/localizationWithResources.jsf
For already translated locales of the calendar, see http://code.google.com/p/primefaces/wiki/PrimeFacesLocales.
Summary
In this article, we learned about setting up and configuring the PrimeFaces library, AJAX basics with process and update, PrimeFaces selectors, and Internationalization (i18n) and Localization (L10n).
Resources for Article:
Further resources on this subject:
- Components of PrimeFaces Extensions [Article]
- JSF2 composite component with PrimeFaces [Article]
- Getting Started with PrimeFaces [Article]
