Vaadin : Widget set is not getting loaded.

Question

I was able to integrate a Vaadin module into our Spring based application. After integration I wanted to run a demo of gantt-charts which is an add-on for Vaadin and found it on github here. Inside the folder, there is a demo project. All is fine, except I am having a problem with widgetsets.

Screenshot of the problem :

Also I get a non-serializable error :

Nov 18, 2015 3:16:48 PM org.apache.catalina.session.StandardManager startInternal
SEVERE: Exception loading sessions from persistent storage
java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: com.journaldev.spring.Vaadin.Util$5
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1355)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924)

UI code :

@Theme("demo")
@SpringUI
@SuppressWarnings("serial")
public class MyVaadinUI extends UI {


    @WebServlet(value = "/testvaadin", asyncSupported = true)
    @VaadinServletConfiguration(productionMode = false, ui = MyVaadinUI.class, widgetset = "org.tltv.gantt.demo.DemoWidgetSet")
    public static class Servlet extends SpringVaadinServlet {
    }

// Code for gaant-chart taken from demo, code too big and not important //for error
// Pastebin link : http://pastebin.com/mi1ZhH30
}

POM.xml :

vaadin-addons http://maven.vaadin.com/vaadin-addons

<!--- Vaadin dependency -->
<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-spring</artifactId>
    <version>1.0.0</version>
</dependency>

<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-themes</artifactId>
    <version>${vaadin.version}</version>
</dependency>

<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-client-compiled</artifactId>
    <version>${vaadin.version}</version>
</dependency>

<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-push</artifactId>
    <version>${vaadin.version}</version>
</dependency>

<dependency>
    <groupId>org.tltv.gantt</groupId>
    <artifactId>gantt-addon</artifactId>
    <version>0.9.0</version>
</dependency>

web.xml :

 <servlet-mapping>
        <servlet-name>vaadin-spring</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>cometd</servlet-name>
        <servlet-class>org.cometd.server.CometDServlet</servlet-class>
        <init-param>
            <param-name>timeout</param-name>
            <param-value>300000</param-value>
        </init-param>
        <load-on-startup>2</load-on-startup>
        <async-supported>true</async-supported>
    </servlet>

What am I doing wrong? Kindly let me know. Thanks a lot. :-)

Answer 1

Try to run mvn clean install to compile the widgetset. If you don't want to use command line, right click in your proyect, Run As > Maven install.

You can also compile your widgetset in eclipse. Open your widgetset file and click in the "gear" symbol in the eclipse menu.

Answer 2

You need the vaadin client-compiler to be able to compile your widgetset. Add the following to your pom.xml:

<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-client-compiler</artifactId>
    <version>${vaadin.version}</version>
    <scope>provided</scope>
</dependency>

And run mvn vaadin:compile to compile your client-side widgetset.

EDIT: Also have a file called com.journaldev.demoset.gwt.xml in your build path:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 1.7.0//EN" "http://google-web-toolkit.googlecode.com/svn/tags/1.7.0/distro-source/core/src/gwt-module.dtd">
<module>
    <inherits name="com.vaadin.DefaultWidgetSet" />

    <add-linker name="xsiframe" />

    <inherits name="org.tltv.gantt.WidgetSet" />

</module>

and change your annotated servlet to read the widgetset from that file.

@WebServlet(value = "/testvaadin", asyncSupported = true)
@VaadinServletConfiguration(productionMode = false, ui = MyVaadinUI.class, widgetset = "com.journaldev.demoset")
public static class Servlet extends SpringVaadinServlet {
} 

With that, you are defining your own widgetset which includes the one defined in the gantt chart project.