Chapter 31. Seam JSF controls

Seam includes a number of JavaServer Faces (JSF) controls to complement built-in controls, and controls from other third-party libraries. We recommend JBoss RichFaces and Apache MyFaces Trinidad tag libraries for use with Seam. We do not recommend the use of the Tomahawk tag library.

31.1. Tags

To use these tags, define the s namespace in your page as follows (Facelets only): 
<html xmlns="http://www.w3.org/1999/xhtml" 
      xmlns:s="http://jboss.com/products/seam/taglib">
The user interface example demonstrates the use of a number of these tags.

31.1.1. Navigation Controls

31.1.1.1. <s:button>

Description
A button that supports invoking an action with control over conversation propagation. This button does not submit the form.
Attributes
  • value — the button label.
  • action — a method binding that specifies the action listener.
  • view — specifies the JSF view ID to link to.
  • fragment — specifies the fragment identifier to link to.
  • disabled — specifies whether the link is disabled.
  • propagation — determines the conversation propagation style: begin, join, nest, none or end.
  • pageflow — specifies a pageflow definition to begin. (Effective only when propagation="begin" or propagation="join" is used.)
Usage 
<s:button id="cancel" value="Cancel" action="#{hotelBooking.cancel}"/>
You can specify both view and action on <s:link />. In this case, the action will be called once the redirect to the specified view has occurred.
The use of action listeners (including the default JSF action listener) is not supported with <s:button />.

31.1.1.2. <s:conversationId>

Description
Adds the conversation ID to a JSF link or button, for example:
<h:commandLink />, <s:button />.
Attributes
None.

31.1.1.3. <s:taskId>

Description
Adds the task ID to an output link (or similar JSF control) when the task is available via #{task}.
Attributes
None.

31.1.1.4. <s:link>

Description
A link that supports invoking an action with control over conversation propagation. This does not submit the form.
The use of action listeners (including the default JSF action listener) is not supported with <s:link />.
Attributes
  • value — specifies the link label.
  • action — a method binding that specifies the action listener.
  • view — specifies the JSF view ID to link to.
  • fragment — specifies the fragment identifier to link to.
  • disabled — specifies whether the link is disabled.
  • propagation — determines the conversation propagation style: begin, join, nest, none or end.
  • pageflow — specifies a pageflow definition to begin. (Effective only when using propagation="begin" or propagation="join".)
Usage 
<s:link id="register" view="/register.xhtml" value="Register New User"/>
You can specify both view and action on <s:link />. In this case, the action will be called once the redirect to the specified view has occurred.

31.1.1.5. <s:conversationPropagation>

Description
Customizes the conversation propagation for a command link or button (or similar JSF control). Facelets only.
Attributes
  • type — determines the conversation propagation style: begin, join, nest, none or end.
  • pageflow — specifies a pageflow definition to begin. (Effective only useful when using propagation="begin" or propagation="join".)
Usage 
<h:commandButton value="Apply" action="#{personHome.update}"> 
  <s:conversationPropagation type="join" /> 
</h:commandButton>

31.1.1.6.  <s:defaultAction>

Description
Specifies the default action to run when the form is submitted using the enter key.
Currently you this can only be nested inside buttons, such as <h:commandButton />, <a:commandButton /> or <tr:commandButton />).
You must specify an ID on the action source, and only one default action can be specified per form.
Attributes
None.
Usage 
<h:commandButton id="foo" value="Foo" action="#{manager.foo}"> 
  <s:defaultAction /> 
</h:commandButton>

31.1.2. Converters and Validators

31.1.2.1. <s:convertDateTime>

Description
Perform date or time conversions in the Seam timezone.
Attributes
None.
Usage 
<h:outputText value="#{item.orderDate}"> 
  <s:convertDateTime type="both" dateStyle="full"/> 
</h:outputText>

31.1.2.2. <s:convertEntity>

Description
Assigns an entity converter to the current component. This is useful for radio button and dropdown controls.
The converter works with any managed entity - either simple or composite. If the converter cannot find the items declared in the JSF controls upon form submission, a validation error will occur.
Attributes
None.
Configuration
You must use Seam managed transactions (see Section 10.2, “Seam managed transactions”) with <s:convertEntity />.
Your Managed Persistence Context must be named entityManager — if it is not, you can change its named in components.xml: 
<components xmlns="http://jboss.com/products/seam/components" 
            xmlns:ui="http://jboss.com/products/seam/ui"> 
<ui:jpa-entity-loader entity-manager="#{em}" />
If you are using a Managed Hibernate Session, you must also set this in components.xml: 
<components xmlns="http://jboss.com/products/seam/components" 
            xmlns:ui="http://jboss.com/products/seam/ui"> 
<ui:hibernate-entity-loader />
Your Managed Hibernate Session must be named session — if it is not, you can change its named in components.xml: 
<components xmlns="http://jboss.com/products/seam/components" 
            xmlns:ui="http://jboss.com/products/seam/ui"> 
<ui:hibernate-entity-loader session="#{hibernateSession}" />
To use multiple entity managers with the entity converter, create a copy of the entity converter for each entity manager in components.xml. The entity converter delegates to the entity loader to perform persistence operations like so: 
<components xmlns="http://jboss.com/products/seam/components" 
            xmlns:ui="http://jboss.com/products/seam/ui"> 
<ui:entity-converter name="standardEntityConverter" 
    entity-loader="#{standardEntityLoader}" /> 
<ui:jpa-entity-loader name="standardEntityLoader" 
    entity-manager="#{standardEntityManager}" /> 
<ui:entity-converter name="restrictedEntityConverter" 
    entity-loader="#{restrictedEntityLoader}" /> 
<ui:jpa-entity-loader name="restrictedEntityLoader" 
    entity-manager="#{restrictedEntityManager}" />

<h:selectOneMenu value="#{person.continent}"> 
  <s:selectItems value="#{continents.resultList}" 
     var="continent" label="#{continent.name}" /> 
  <f:converter converterId="standardEntityConverter" /> 
</h:selectOneMenu>
Usage 
<h:selectOneMenu value="#{person.continent}" required="true"> 
  <s:selectItems value="#{continents.resultList}" var="continent" 
     label="#{continent.name}" noSelectionLabel="Please Select..."/> 
  <s:convertEntity /> 
</h:selectOneMenu>

31.1.2.3. <s:convertEnum>

Description
Assigns an enum converter to the current component. This is primarily useful for radio button and dropdown controls.
Attributes
None.
Usage 
<h:selectOneMenu value="#{person.honorific}"> 
  <s:selectItems value="#{honorifics}" var="honorific" 
     label="#{honorific.label}" noSelectionLabel="Please select" /> 
  <s:convertEnum /> 
</h:selectOneMenu>

31.1.2.4. <s:convertAtomicBoolean>

Description
javax.faces.convert.Converter for java.util.concurrent.atomic.AtomicBoolean.
Attributes
None.
Usage 
<h:outputText value="#{item.valid}"> 
  <s:convertAtomicBoolean /> 
</h:outputText>

31.1.2.5. <s:convertAtomicInteger>

Description
javax.faces.convert.Converter for java.util.concurrent.atomic.AtomicInteger.
Attributes
None.
Usage 
<h:outputText value="#{item.id}"> 
  <s:convertAtomicInteger /> 
</h:outputText>

31.1.2.6. <s:convertAtomicLong>

Description
javax.faces.convert.Converter for java.util.concurrent.atomic.AtomicLong.
Attributes
None.
Usage 
<h:outputText value="#{item.id}"> 
  <s:convertAtomicLong /> 
</h:outputText>

31.1.2.7. <s:validateEquality>

Description
Validates that an input control's parent's value is equal, or not equal, to the referenced control's value.
Attributes
  • for — The ID of a control to validate against.
  • message — Message to show on failure.
  • required — False will disable a check that a value at all is inputted in fields.
  • messageId — Message ID to show on failure.
  • operator — The operator to use when comparing values. Valid operators are:
    • equal — validates that value.equals(forValue).
    • not_equal — validates that !value.equals(forValue)
    • greater — validates that ((Comparable)value).compareTo(forValue) > 0
    • greater_or_equal — validates that ((Comparable)value).compareTo(forValue) >= 0
    • less — validates that ((Comparable)value).compareTo(forValue) < 0
    • less_or_equal — validates that ((Comparable)value).compareTo(forValue) <= 0
Usage 
<h:inputText id="name" value="#{bean.name}"/> 
<h:inputText id="nameVerification" > 
  <s:validateEquality for="name" /> 
</h:inputText>

31.1.2.8. <s:validate>

Description
A non-visual control that validates a JSF input field against the bound property with the Hibernate Validator.
Attributes
None.
Usage 
<h:inputText id="userName" required="true" value="#{customer.userName}"> 
  <s:validate /> 
</h:inputText> 
<h:message for="userName" styleClass="error" />

31.1.2.9. <s:validateAll>

Description
A non-visual control that validates all child JSF input fields against their bound properties with the Hibernate Validator.
Attributes
None.
Usage 
<s:validateAll> 
  <div class="entry"> 
    <h:outputLabel for="username">Username:</h:outputLabel> 
    <h:inputText id="username" value="#{user.username}" required="true"/> 
    <h:message for="username" styleClass="error" /> 
  </div> 
  <div class="entry"> 
    <h:outputLabel for="password">Password:</h:outputLabel> 
    <h:inputSecret id="password" value="#{user.password}" 
     required="true"/> 
    <h:message for="password" styleClass="error" /> 
  </div> 
  <div class="entry"> 
    <h:outputLabel for="verify">Verify Password:</h:outputLabel> 
    <h:inputSecret id="verify" value="#{register.verify}" 
     required="true"/> 
    <h:message for="verify" styleClass="error" /> 
  </div> 
</s:validateAll>

31.1.3. Formatting

31.1.3.1. <s:decorate>

Description
"Decorates" a JSF input field when validation fails or when required="true" is set.
Attributes
  • template — the Facelets template used to decorate the component.
  • enclose — if true, the template used to decorate the input field is enclosed by the element specified with the "element" attribute. (By default, this is a div element.)
  • element — the element enclosing the template that decorates the input field. By default, the template is enclosed with a div element.
#{invalid} and #{required} are available inside s:decorate. #{required} evaluates to true if the input component being decorated is set to required. #{invalid} evaluates to true if a validation error occurs.
Usage 
<s:decorate template="edit.xhtml"> 
  <ui:define name="label">Country:</ui:define> 
  <h:inputText value="#{location.country}" required="true"/> 
</s:decorate>

<ui:composition xmlns="http://www.w3.org/1999/xhtml" 
    xmlns:ui="http://java.sun.com/jsf/facelets" 
    xmlns:h="http://java.sun.com/jsf/html" 
    xmlns:f="http://java.sun.com/jsf/core" 
    xmlns:s="http://jboss.com/products/seam/taglib"> 
  <div>   
    <s:label styleClass="#{invalid?'error':''}"> 
      <ui:insert name="label"/> 
      <s:span styleClass="required" rendered="#{required}">*</s:span> 
    </s:label> 
    <span class="#{invalid?'error':''}"> 
      <s:validateAll> 
        <ui:insert/> 
      </s:validateAll> 
    </span> 
    <s:message styleClass="error"/>     
  </div>   
</ui:composition>

31.1.3.2. <s:div>

Description
Renders a HTML <div>.
Attributes
None.
Usage 
<s:div rendered="#{selectedMember == null}"> 
  Sorry, but this member does not exist. 
</s:div>

31.1.3.3. <s:span>

Description
Renders a HTML <span>.
Attributes
  • title — Title for a span.
Usage 
<s:span styleClass="required" rendered="#{required}" title="Small tooltip">
  *
</s:span>

31.1.3.4. <s:fragment>

Description
A non-rendering component useful for enabling/disabling rendering of it's children.
Attributes
None.
Usage 
<s:fragment rendered="#{auction.highBidder ne null}"> 
  Current bid: 
</s:fragment>

31.1.3.5. <s:label>

Description
"Decorates" a JSF input field with the label. The label is placed inside the HTML <label> tag, and is associated with the nearest JSF input component. It is often used with <s:decorate>.
Attributes
  • style — The control's style.
  • styleClass — The control's style class.
Usage 
<s:label styleClass="label"> Country: </s:label> 
<h:inputText value="#{location.country}" required="true"/>

31.1.3.6. <s:message>

Description
"Decorates" a JSF input field with the validation error message.
Attributes
None.
Usage 
<f:facet name="afterInvalidField"> 
  <s:span>  
    Error: 
    <s:message/> 
  </s:span> 
</f:facet>

31.1.4. Seam Text

31.1.4.1. <s:validateFormattedText>

Description
Checks that the submitted value is valid Seam Text.
Attributes
None.

31.1.4.2. <s:formattedText>

Description
Outputs Seam Text, a rich text markup useful for blogs, wikis and other applications that might use rich text. See the Seam Text chapter for full usage.
Attributes
  • value — an EL expression specifying the rich text markup to render.
Usage 
<s:formattedText value="#{blog.text}"/>
Example

31.1.5. Form support

31.1.5.1. <s:token>

Description
Produces a random token to insert into a hidden form field in order to secure JSF form posts against Cross-Site Request Forgery (XSRF) attacks. The browser must have cookies enabled to submit forms that include this component.
Attributes
  • requireSession — indicates whether the session ID should be included in the form signature to bind the token to the session. The default value is false, but this should only be used if Facelets is in "build before restore" mode. ("Build before restore" is the default mode in JSF 2.0.)
  • enableCookieNotice — indicates that a JavaScript check should be inserted into the page to verify that cookies are enabled in the browser. If cookies are not enabled, present a notice to the user that form posts will not work. The default value is false.
  • allowMultiplePosts — indicates whether the same form is allowed to submit multiple times with the same signature (where the view has not changed). This is often required when the form is performing AJAX calls without rerendering itself or the UIToken component. It is better to rerender the UIToken component upon any AJAX call where the UIToken component would be processed. The default value is false.
Usage 
<h:form> 
  <s:token enableCookieNotice="true" requireSession="false"/> 
  ... 
</h:form>

31.1.5.2. <s:enumItem>

Description
Creates a SelectItem from an enum value.
Attributes
  • enumValue — the string representation of the enum value.
  • label — the label to be used when rendering the SelectItem.
Usage 
<h:selectOneRadio id="radioList" 
                  layout="lineDirection" 
 value="#{newPayment.paymentFrequency}">
   <s:convertEnum />
   <s:enumItem enumValue="ONCE"         label="Only Once" />
   <s:enumItem enumValue="EVERY_MINUTE" label="Every Minute" />
   <s:enumItem enumValue="HOURLY"       label="Every Hour" />
   <s:enumItem enumValue="DAILY"        label="Every Day" />
   <s:enumItem enumValue="WEEKLY"       label="Every Week" />
</h:selectOneRadio>

31.1.5.3. <s:selectItems>

Description
Creates a List<SelectItem> from a List, Set, DataModel or Array.
Attributes
  • value — an EL expression specifying the data that backs the ListSelectItem>
  • var — defines the name of the local variable that holds the current object during iteration.
  • label — the label to be used when rendering the SelectItem. Can reference the var variable.
  • itemValue — specifies the value to return to the server if this option is selected. This is an optional attribute. If included, var is the default object used. Can reference the var variable.
  • disabled — if this is set to true, the SelectItem will be rendered disabled. Can reference the var variable.
  • noSelectionLabel — specifies the (optional) label to place at the top of list. If required="true" is also specified then selecting this value will cause a validation error.
  • hideNoSelectionLabel — if true, the noSelectionLabel will be hidden when a value is selected.
Usage 
<h:selectOneMenu value="#{person.age}" converter="ageConverter"> 
  <s:selectItems value="#{ages}" var="age" label="#{age}" /> 
</h:selectOneMenu>

31.1.5.4. <s:fileUpload>

Description
Renders a file upload control. This control must be used within a form with an encoding type of multipart/form-data: 
<h:form enctype="multipart/form-data">
For multipart requests, the Seam Multipart servlet filter must also be configured in web.xml: 
<filter> 
  <filter-name>Seam Filter</filter-name> 
  <filter-class>org.jboss.seam.servlet.SeamFilter</filter-class> 
</filter> 
<filter-mapping> 
  <filter-name>Seam Filter</filter-name> 
  <url-pattern>/*</url-pattern> 
</filter-mapping>
Configuration
The following configuration options for multipart requests can be configured in components.xml:
  • createTempFiles — if this option is set to true, uploaded files are streamed to a temporary file rather than being held in memory.
  • maxRequestSize — the maximum size of a file upload request, in bytes.
Here's an example: 
<component class="org.jboss.seam.web.MultipartFilter"> 
  <property name="createTempFiles">true</property> 
  <property name="maxRequestSize">1000000</property> 
</component>
Attributes
  • data — specifies the value binding that receives the binary file data. The receiving field must be declared as either a byte[] or InputStream.
  • contentType — an optional attribute specifying the value binding that receives the file's content type.
  • fileName — an optional attribute specifying the value binding that receives the filename.
  • fileSize — an optional attribute specifying the value binding that receives the file size.
  • accept — a comma-separated list of acceptable content types, for example, "images/png,images/jpg", "images/*". The types listed may not be supported by the browser.
  • style — The control's style.
  • styleClass — The control's style class.
Usage 
<s:fileUpload id="picture" 
              data="#{register.picture}" accept="image/png" 
              contentType="#{register.pictureContentType}" />

31.1.6. Other

31.1.6.1. <s:cache>

Description
Caches the rendered page fragment using JBoss Cache. Note that <s:cache> actually uses the instance of JBoss Cache managed by the built-in pojoCache component.
Attributes
  • key — the key to cache rendered content, often a value expression. For example, if we were caching a page fragment that displays a document, we might use key="Document-#{document.id}".
  • enabled — a value expression that determines whether the cache should be used.
  • region — specifies the JBoss Cache node to use. Different nodes can have different expiry policies.
Usage 
<s:cache key="entry-#{blogEntry.id}" region="pageFragments">
  <div class="blogEntry">
    <h3>#{blogEntry.title}</h3>
    <div>
      <s:formattedText value="#{blogEntry.body}"/>
    </div>
    <p>
      [Posted on 
      <h:outputText value="#{blogEntry.date}">
        <f:convertDateTime timezone="#{blog.timeZone}" 
         locale="#{blog.locale}" type="both"/>
      </h:outputText>]
    </p>
  </div>
</s:cache>

31.1.6.2. <s:resource>

Description
A tag that acts as a file download provider. It must be alone in the JSF page. To use this control, you must configure web.xml as follows:
Configuration 
<servlet> 
  <servlet-name>Document Store Servlet</servlet-name> 
  <servlet-class>
    org.jboss.seam.document.DocumentStoreServlet
  </servlet-class> 
</servlet> 
<servlet-mapping> 
  <servlet-name>Document Store Servlet</servlet-name> 
  <url-pattern>/seam/docstore/*</url-pattern> 
</servlet-mapping>
Attributes
  • data — specifies data that should be downloaded. May be a java.util.File, an InputStream or a byte array.
  • fileName — the filename of the file to be served.
  • contentType — the content type of the file to be downloaded.
  • disposition — the disposition to use. The default disposition is inline.
Usage
The tag is used as follows: 
<s:resource xmlns="http://www.w3.org/1999/xhtml" 
   xmlns:s="http://jboss.com/products/seam/taglib" 
   data="#{resources.data}" contentType="#{resources.contentType}" 
   fileName="#{resources.fileName}" />
Here, the bean named resources is some backing bean that, given some request parameters, serves a specific file — see s:download.

31.1.6.3. <s:download>

Description
Builds a RESTful link to a <s:resource>. Nested f:param build up the url.
  • src — Resource file serving files.
Attributes 
<s:download src="/resources.xhtml"> 
  <f:param name="fileId" value="#{someBean.downloadableFileId}"/> 
</s:download>
This produces a link of a similar form to the following: http://localhost/resources.seam?fileId=1

31.1.6.4. <s:graphicImage>

Description
An extended <h:graphicImage> that allows the image to be created in a Seam Component. It is possible to transform the image further.
All <h:graphicImage> attributes are supported, in addition to:
Attributes
  • value — specifies the image to display. Can be a path String (loaded from the classpath), a byte[], a java.io.File, a java.io.InputStream or a java.net.URL. Currently supported image formats are image/bmp, image/png, image/jpeg and image/gif.
  • fileName — specifies the filename of the image. This name should be unique. If left unspecified, a unique filename will be generated for the image.
Transformations
To transform the image, nest a tag specifying which transformation to apply. Seam currently supports the following transformation tags:
<s:transformImageSize>
  • width — specifies the new width of the image.
  • height — specifies the new height of the image.
  • maintainRatio — if true, and one of either width or height is specified, the image will be resized to maintain the height:width aspect ratio.
  • factor — scales the image by the specified factor.
<s:transformImageBlur>
  • radius — performs a convolution blur with the specified radius.
<s:transformImageType>
  • contentType — alters the image type to either image/jpeg or image/png.
You can also create your own image transformation. Create a UIComponent that implements org.jboss.seam.ui.graphicImage.ImageTransform. Inside the applyTransform()method, use image.getBufferedImage() to get the original image and image.setBufferedImage() to set your transformed image. Transforms are applied in the order specified in the view.
Usage 
<s:graphicImage rendered="#{auction.image ne null}" 
   value="#{auction.image.data}"> 
  <s:transformImageSize width="200" maintainRatio="true"/> 
</s:graphicImage>

31.1.6.5. <s:remote>

Description
Generates the Javascript stubs required to use Seam Remoting.
Attributes
  • include — a comma-separated list of the component names (or fully qualified class names) for which to generate Seam Remoting Javascript stubs. See Chapter 24, Remoting for more details.
Usage 
<s:remote include="customerAction,accountAction,com.acme.MyBean"/>