jsf - @FacesComponent not displayed properly - Stack Overflow

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Trying to jump into learning Jakarta EE 10+, with Jakarta Faces 4+. With a simple example on creating a custom componant (tag) the rendering of it is not done properly.

Added some System.out.prinln but from DataList.java or DataListRenderer.java none are printed, only from Bean.java.

I use OpenJDK 23 (at the time of writing trying OpenJDK 21), Glassfish 7.0.22, Maven 3.9.9, and NetBeans 25.

Before posting all artifacts, here is how the genereated HTML code looks like, on the index.xhtml page nothing is shown:

<!DOCTYPE html>
<html xmlns:t="example.tags">
    <head id="j_idt2">
        <title>Data List Example</title>
    </head>
    <body>
        <form 
            id="j_idt5" 
            name="j_idt5" 
            method="post" 
            action="/chapter11-01/index.xhtml" 
            enctype="application/x-www-form-urlencoded">

            <input type="hidden" name="j_idt5" value="j_idt5" />

            <t:dataList value="[Item 1, Item 2, Item 3, Item 4]" var="item"></t:dataList>

            <input 
                type="hidden" 
                name="jakarta.faces.ViewState" 
                id="j_id1:jakarta.faces.ViewState:0" 
                value="-7332627109196662398:-1565591830560270214" 
                autocomplete="off" />
        </form>
    </body>
</html>

Here are the artifacts:

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns=".0.0" xmlns:xsi="; xsi:schemaLocation=".0.0 .0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>chapter-11-01</artifactId>
    <version>0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>chapter-11-01</name>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.report.sourceEncoding>UTF-8</project.report.sourceEncoding>
        <mavenpiler.release>21</mavenpiler.release>
        <jakartaee-api.version>10.0.0</jakartaee-api.version>
        <compiler-plugin.version>3.13.0</compiler-plugin.version>
        <war-plugin.version>3.4.0</war-plugin.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>jakarta.platform</groupId>
            <artifactId>jakarta.jakartaee-api</artifactId>
            <version>${jakartaee-api.version}</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <finalName>chapter-11-01</finalName>
        <plugins>
            <plugin>
                <groupId>.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>${compiler-plugin.version}</version>
            </plugin>
            <plugin>
                <artifactId>maven-war-plugin</artifactId>
                <version>${war-plugin.version}</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>

        </plugins>
    </build>
</project>

/src/main/webapp/index.xhtml

<!DOCTYPE html>
<html xmlns:h="jakarta.faces.html" xmlns:t="example.tags">
    <h:head>
        <title>Data List Example</title>
    </h:head>
    <h:body>
        <h:form>
            <t:dataList value="#{bean.items}" var="item">
                <h:outputText value="#{item}" />
            </t:dataList>
        </h:form>
    </h:body>
</html>

/src/main/webapp/WEB-INF/web.xml

<web-app version="6.0"
    xmlns=";
    xmlns:xsi=";
    xsi:schemaLocation=" .xsd">
    
    <welcome-file-list>
        <welcome-file>index.xhtml</welcome-file>
    </welcome-file-list>
    
    <servlet>
        <servlet-name>faces</servlet-name>
        <servlet-class>jakarta.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>faces</servlet-name>
        <url-pattern>*.xhtml</url-pattern>
    </servlet-mapping>    
</web-app>

/src/main/webapp/WEB-INF/beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans 
    xmlns=";
    xmlns:xsi=";
    xsi:schemaLocation=" .xsd"
    version="4.0" 
    bean-discovery-mode="annotated">
</beans>

/src/main/webapp/WEB-INF/faces-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<faces-config 
    xmlns=";
    xmlns:xsi=";
    xsi:schemaLocation=" .xsd"
    version="4.0">
    
    <render-kit>
        <renderer>
            <component-family>jakarta.faces.Data</component-family>
            <renderer-type>example.List</renderer-type>
            <renderer-class>com.example.renderer.DataListRenderer</renderer-class>
        </renderer>
    </render-kit>
</faces-config>

/src/main/webapp/WEB-INF/example.taglib.xml

<?xml version="1.0" encoding="UTF-8"?> 
<facelet-taglib 
    xmlns="; 
    xmlns:xsi="; 
    xsi:schemaLocation=" .xsd" 
    version="4.0" > 
    
    <namespace>example.tags</namespace> 
    <short-name>t</short-name> <!-- Other tags here --> 
    <tag> 
        <description>Renders a HTML list.</description> 
        <tag-name>dataList</tag-name> 
        <component> 
            <component-type>com.exampleponent.DataList</component-type> 
        </component> 
    </tag> 
</facelet-taglib>

/src/main/java/com/example/bean/Bean.java

package com.example.bean;

import jakarta.enterprise.context.SessionScoped;
import jakarta.inject.Named;
import java.io.Serializable;
import java.util.Arrays;
import java.util.List;

@Named
@SessionScoped
public class Bean implements Serializable {

    private List<String> items;

    public Bean() {
        items = Arrays.asList("Item 1", "Item 2", "Item 3", "Item 4");
    }

    public List<String> getItems() {
        return items;
    }
}

/src/main/java/com/example/component/DataList.java

package com.exampleponent;

import com.example.renderer.DataListRenderer;
import jakarta.facesponent.FacesComponent;
import jakarta.facesponent.UIData;

@FacesComponent
public class DataList extends UIData {
    public DataList() {
        setRendererType(DataListRenderer.RENDERER_TYPE);
        System.out.println("DataList component initialized.");
    }
}

/src/main/java/com/example/renderer/DataListRenderer.java

package com.example.renderer;

import jakarta.facesponent.UIComponent;
import jakarta.facesponent.UIData;
import jakarta.faces.context.FacesContext;
import jakarta.faces.context.ResponseWriter;
import jakarta.faces.render.FacesRenderer;
import jakarta.faces.render.Renderer;
import java.io.IOException;

@FacesRenderer(
    componentFamily = UIData.COMPONENT_FAMILY, 
    rendererType = DataListRenderer.RENDERER_TYPE
)
public class DataListRenderer extends Renderer {

    public static final String RENDERER_TYPE = "example.List";

    @Override
    public void encodeBegin(FacesContext context, UIComponent component) throws IOException {
        ResponseWriter writer = context.getResponseWriter();
        UIData data = (UIData) component;
        
        System.out.println("encodeBegin() - Row count: " + data.getRowCount());
        
        if (data.getRowCount() > 0) {
            writer.startElement("ul", component);
        }
    }

    @Override
    public boolean getRendersChildren() {
        return true;
    }

    @Override
    public void encodeChildren(FacesContext context, UIComponent component) throws IOException {
        ResponseWriter writer = context.getResponseWriter();
        UIData data = (UIData) component;
        
        System.out.println("encodeChildren() called");
        
        for (int i = 0; i < data.getRowCount(); i++) {
            data.setRowIndex(i);
            writer.startElement("li", component);
            if (component.getChildCount() > 0) {
                for (UIComponent child : component.getChildren()) {
                    child.encodeAll(context);
                }
            }
            writer.endElement("li");
        }
        data.setRowIndex(-1);
    }

    @Override
    public void encodeEnd(FacesContext context, UIComponent component) throws IOException {
        ResponseWriter writer = context.getResponseWriter();
        UIData data = (UIData) component;
        
        System.out.println("encodeEnd() - Row count: " + data.getRowCount());
        
        if (data.getRowCount() > 0) {
            writer.endElement("ul");
        }
    }
}

Trying to jump into learning Jakarta EE 10+, with Jakarta Faces 4+. With a simple example on creating a custom componant (tag) the rendering of it is not done properly.

Added some System.out.prinln but from DataList.java or DataListRenderer.java none are printed, only from Bean.java.

I use OpenJDK 23 (at the time of writing trying OpenJDK 21), Glassfish 7.0.22, Maven 3.9.9, and NetBeans 25.

Before posting all artifacts, here is how the genereated HTML code looks like, on the index.xhtml page nothing is shown:

<!DOCTYPE html>
<html xmlns:t="example.tags">
    <head id="j_idt2">
        <title>Data List Example</title>
    </head>
    <body>
        <form 
            id="j_idt5" 
            name="j_idt5" 
            method="post" 
            action="/chapter11-01/index.xhtml" 
            enctype="application/x-www-form-urlencoded">

            <input type="hidden" name="j_idt5" value="j_idt5" />

            <t:dataList value="[Item 1, Item 2, Item 3, Item 4]" var="item"></t:dataList>

            <input 
                type="hidden" 
                name="jakarta.faces.ViewState" 
                id="j_id1:jakarta.faces.ViewState:0" 
                value="-7332627109196662398:-1565591830560270214" 
                autocomplete="off" />
        </form>
    </body>
</html>

Here are the artifacts:

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache./POM/4.0.0" xmlns:xsi="http://www.w3./2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache./POM/4.0.0 http://maven.apache./xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>chapter-11-01</artifactId>
    <version>0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>chapter-11-01</name>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.report.sourceEncoding>UTF-8</project.report.sourceEncoding>
        <mavenpiler.release>21</mavenpiler.release>
        <jakartaee-api.version>10.0.0</jakartaee-api.version>
        <compiler-plugin.version>3.13.0</compiler-plugin.version>
        <war-plugin.version>3.4.0</war-plugin.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>jakarta.platform</groupId>
            <artifactId>jakarta.jakartaee-api</artifactId>
            <version>${jakartaee-api.version}</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <finalName>chapter-11-01</finalName>
        <plugins>
            <plugin>
                <groupId>.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>${compiler-plugin.version}</version>
            </plugin>
            <plugin>
                <artifactId>maven-war-plugin</artifactId>
                <version>${war-plugin.version}</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>

        </plugins>
    </build>
</project>

/src/main/webapp/index.xhtml

<!DOCTYPE html>
<html xmlns:h="jakarta.faces.html" xmlns:t="example.tags">
    <h:head>
        <title>Data List Example</title>
    </h:head>
    <h:body>
        <h:form>
            <t:dataList value="#{bean.items}" var="item">
                <h:outputText value="#{item}" />
            </t:dataList>
        </h:form>
    </h:body>
</html>

/src/main/webapp/WEB-INF/web.xml

<web-app version="6.0"
    xmlns="https://jakarta.ee/xml/ns/jakartaee"
    xmlns:xsi="http://www.w3./2001/XMLSchema-instance"
    xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_6_0.xsd">
    
    <welcome-file-list>
        <welcome-file>index.xhtml</welcome-file>
    </welcome-file-list>
    
    <servlet>
        <servlet-name>faces</servlet-name>
        <servlet-class>jakarta.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>faces</servlet-name>
        <url-pattern>*.xhtml</url-pattern>
    </servlet-mapping>    
</web-app>

/src/main/webapp/WEB-INF/beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans 
    xmlns="https://jakarta.ee/xml/ns/jakartaee"
    xmlns:xsi="http://www.w3./2001/XMLSchema-instance"
    xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/beans_4_0.xsd"
    version="4.0" 
    bean-discovery-mode="annotated">
</beans>

/src/main/webapp/WEB-INF/faces-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<faces-config 
    xmlns="https://jakarta.ee/xml/ns/jakartaee"
    xmlns:xsi="http://www.w3./2001/XMLSchema-instance"
    xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/faces-config_4_0.xsd"
    version="4.0">
    
    <render-kit>
        <renderer>
            <component-family>jakarta.faces.Data</component-family>
            <renderer-type>example.List</renderer-type>
            <renderer-class>com.example.renderer.DataListRenderer</renderer-class>
        </renderer>
    </render-kit>
</faces-config>

/src/main/webapp/WEB-INF/example.taglib.xml

<?xml version="1.0" encoding="UTF-8"?> 
<facelet-taglib 
    xmlns="https://jakarta.ee/xml/ns/jakartaee" 
    xmlns:xsi="http://www.w3./2001/XMLSchema-instance" 
    xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-facelettaglibrary_4_0.xsd" 
    version="4.0" > 
    
    <namespace>example.tags</namespace> 
    <short-name>t</short-name> <!-- Other tags here --> 
    <tag> 
        <description>Renders a HTML list.</description> 
        <tag-name>dataList</tag-name> 
        <component> 
            <component-type>com.exampleponent.DataList</component-type> 
        </component> 
    </tag> 
</facelet-taglib>

/src/main/java/com/example/bean/Bean.java

package com.example.bean;

import jakarta.enterprise.context.SessionScoped;
import jakarta.inject.Named;
import java.io.Serializable;
import java.util.Arrays;
import java.util.List;

@Named
@SessionScoped
public class Bean implements Serializable {

    private List<String> items;

    public Bean() {
        items = Arrays.asList("Item 1", "Item 2", "Item 3", "Item 4");
    }

    public List<String> getItems() {
        return items;
    }
}

/src/main/java/com/example/component/DataList.java

package com.exampleponent;

import com.example.renderer.DataListRenderer;
import jakarta.facesponent.FacesComponent;
import jakarta.facesponent.UIData;

@FacesComponent
public class DataList extends UIData {
    public DataList() {
        setRendererType(DataListRenderer.RENDERER_TYPE);
        System.out.println("DataList component initialized.");
    }
}

/src/main/java/com/example/renderer/DataListRenderer.java

package com.example.renderer;

import jakarta.facesponent.UIComponent;
import jakarta.facesponent.UIData;
import jakarta.faces.context.FacesContext;
import jakarta.faces.context.ResponseWriter;
import jakarta.faces.render.FacesRenderer;
import jakarta.faces.render.Renderer;
import java.io.IOException;

@FacesRenderer(
    componentFamily = UIData.COMPONENT_FAMILY, 
    rendererType = DataListRenderer.RENDERER_TYPE
)
public class DataListRenderer extends Renderer {

    public static final String RENDERER_TYPE = "example.List";

    @Override
    public void encodeBegin(FacesContext context, UIComponent component) throws IOException {
        ResponseWriter writer = context.getResponseWriter();
        UIData data = (UIData) component;
        
        System.out.println("encodeBegin() - Row count: " + data.getRowCount());
        
        if (data.getRowCount() > 0) {
            writer.startElement("ul", component);
        }
    }

    @Override
    public boolean getRendersChildren() {
        return true;
    }

    @Override
    public void encodeChildren(FacesContext context, UIComponent component) throws IOException {
        ResponseWriter writer = context.getResponseWriter();
        UIData data = (UIData) component;
        
        System.out.println("encodeChildren() called");
        
        for (int i = 0; i < data.getRowCount(); i++) {
            data.setRowIndex(i);
            writer.startElement("li", component);
            if (component.getChildCount() > 0) {
                for (UIComponent child : component.getChildren()) {
                    child.encodeAll(context);
                }
            }
            writer.endElement("li");
        }
        data.setRowIndex(-1);
    }

    @Override
    public void encodeEnd(FacesContext context, UIComponent component) throws IOException {
        ResponseWriter writer = context.getResponseWriter();
        UIData data = (UIData) component;
        
        System.out.println("encodeEnd() - Row count: " + data.getRowCount());
        
        if (data.getRowCount() > 0) {
            writer.endElement("ul");
        }
    }
}

Share edited Mar 8 at 13:12 BalusC 1.1m376 gold badges3.7k silver badges3.6k bronze badges asked Mar 4 at 11:32 neblaz 7551 gold badge14 silver badges39 bronze badges

Add a comment |

2 Answers 2

Sorted by: Reset to default 3

According to this part of the Faces spec: https://jakarta.ee/specifications/faces/4.0/jakarta-faces-4.0#a5638, you’re missing one more thing - define reference to your taglib xml file in web.xml, using the servlet context parameter. It would have value of “/WEB-INF/example.taglib.xml”

Like Ondro suggested, adding the <context-param> to web.xml was necessary:

<context-param>
    <param-name>jakarta.faces.FACELETS_LIBRARIES</param-name>
    <param-value>/WEB-INF/example.taglib.xml</param-value>
</context-param>

But in addition also modifying @FacesConfig of DataList.java:

@FacesComponent(value = "com.exampleponent.DataList")
public class DataList extends UIData {

Otherwise DataList still couldn't be found.

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jsf - @FacesComponent not displayed properly - Stack Overflow

2 Answers 2

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