JSF Primefaces: How to use ternary operator for items inside a <f:selectItems> rendered HTML dropdown list?

Viewed 434

Am using JSF Primefaces 7.0 to render an XHTML file to display a list of users (along with their e-mail addresses) inside a single HTML dropdown list.


pom.xml:

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.10</version>
</dependency>

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.16</version>
    <scope>provided</scope>
</dependency>

<dependency>
    <groupId>org.primefaces</groupId>
    <artifactId>primefaces</artifactId>
    <version>7.0</version>
</dependency>

<dependency>
    <groupId>org.primefaces.extensions</groupId>
    <artifactId>primefaces-extensions</artifactId>
    <version>7.0.3</version>
</dependency>

User class:

package com.myapp.model;

import static org.apache.commons.lang3.StringUtils.isBlank;

import lombok.Data;
import lombok.Getter;
import lombok.Setter;
import lombok.NoArgsConstructor;

@NoArgsConstructor
@Data
public class User implements Serializable {

    private String firstName;

    private String lastName; 

    // this is their e-mail address
    private String username; 

    public String getName() {

        final StringBuilder sb = new StringBuilder();
     
        if (!isBlank(getFirstName())) {
            sb.append(getFirstName()).append(' ');
        }
     
        if (!isBlank(getLastName())) {
            sb.append(getLastName());
        }
     
        return sb.toString().trim();
    }
}

Inside users.xhtml:

<html
    xmlns="http://www.w3.org/1999/xhtml"
    xmlns:p="http://primefaces.org/ui"
    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:c="http://java.sun.com/jstl/core"
>
    <f:selectItems
       value="#{userReport.users}"
       var="user"
       itemLabel="#{user.name} (#{user.username})"
       itemValue="#{user}"/>
    </p:selectOneMenu>
</html>

This renders correctly for an individual item if the (user.name is not null) inside an HTML dropdown list:

John Doe (jdoe@email.com)


How can I use a conditional (<c:if> with <c:else> or even the ? : ternary operator) to set the itemLabel attribute to render just the user.username without parenthesis if the user.name is empty string or null?

So, it should set to this (the e-mail address) if user.name is null or an empty string:

itemLabel="#{user.username}"

To make display (if user.name is null or empty string):

jdoe@email.com


Tried doing this:

itemLabel="#{not empty user.name ? user.name (user.username) : user.username}"

Which gives me the following stack trace:


javax.servlet.ServletException: Method not found: class com.myapp.model.User.name(java.lang.String)
    at javax.faces.webapp.FacesServlet.executeLifecyle(FacesServlet.java:749)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:475)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
Caused by: javax.el.MethodNotFoundException: Method not found: class com.myapp.model.User.name(java.lang.String)
    at javax.el.Util.findWrapper(Util.java:373)
    at javax.el.Util.findMethod(Util.java:219)
    at javax.el.BeanELResolver.invoke(BeanELResolver.java:149)
    at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:79)
    ... 35 more

Don't understand why this is the case because the original attribute did find the User.getName() method:

itemLabel="#{user.name} (#{user.username})"

Is there a better way to do this?

1 Answers

Figured it out by using the += concatenation operator:

itemLabel="#{!empty user.name ? user.name += ' (' += user.username += ')' : user.username}"
Related