Category: Fun

Using Oracle JET with VisionX/JVx

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The shiny new technology from Oracle is JET (Javascript Extension Toolkit). It's a really interesting thing because it bundles relevant technologies like jQuery, jQuery UI, Knockout, Require, Hammer, ...

You don't need know-how for every used technology, only JET is enough. This is a nice and new approach in the JS world. A possible problem with such an approach could be the update of single libraries, but this isn't your problem because Oracle has to maintain the right versions and bugfixes in JET. So it's not our problem :)

I'm not a big fan of Javascript libraries/technologies but from time to time I like to play around with such things and proof the interaction with JVx. Some time ago my new friend was AngularJS.

This time, I tried to work with Oracle JET.

The use-case was trivial: I'd like to visualize a list of contacts as simple table. The contacts are available as REST service. The REST service needs basic authentication.

Foreword: JET has much documentation and some useful examples, but it's inconsistent because the documentation shows different solutions for the same problem and you don't know which is best or recommended. And the examples are sometimes too complex. The start with existing examples is simple but if you start coding, it's not so simple. But this is a documentation problem and has nothing to do with the product itself. I prefer source code to find out how things work and this procedure worked without problems for JET.

Foreword 2: I couldn't find a description for Basic authentication. Not in the forum, not in the documentation and not in different blog posts. But I found many questions regarding Basic authentication. I found a solution for the problem but if someone has a better solution, please add a comment. My solution is more or less not API compliant - but works with JET version 1.1.2 and hopefully with newer versions as well.


I've used our VisionX tool and the Contacts demo application for this example because VisionX has an embedded tomcat and REST access is pre-configured. It's not tricky to use any other simple JVx application but it requires more work because you need an application server and a deployed application.

The Trial version of VisionX is a good start. Before I show you the source code, I'll show you the result:

Contacts table

Contacts table

You're right, this isn't rocket science. But it's not hard to add more columns and some css.

What about the source code?

We have one html page, index.html:

<!DOCTYPE html>

    <title>JET with VisionX/JVx</title>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="icon" href="css/images/favicon.ico" type="image/x-icon" />

    <link rel="stylesheet" href="css/libs/oj/v1.1.2/alta/oj-alta-min.css" type="text/css"/>
    <link rel="stylesheet" href="css/demo-alta-patterns-min.css"/>
    <link rel="stylesheet" href="css/override.css" type="text/css"/>

    <script data-main="js/main" src="js/libs/require/require.js"></script>
    <div id="mainContent" class="oj-md-12 oj-col page-padding">
      <div class="demo-page-content-area page-padding">  
        <h1>Contacts via VisionX</h1>
        <table id="table"
          data-bind="ojComponent: {component: 'ojTable',
                                   data: dataSource,
                                   columns: [{headerText: '#',
                                              field: 'ID', sortable: 'enabled'},
                                             {headerText: 'First name',
                                              field: 'FIRSTNAME', sortable: 'enabled'},
                                             {headerText: 'Last name',
                                              field: 'LASTNAME'}]}">


We need two javascript files, main.js:

    paths: {
        'knockout': 'libs/knockout/knockout-3.3.0',
        'jquery': 'libs/jquery/jquery-2.1.3.min',
        'jqueryui-amd': 'libs/jquery/jqueryui-amd-1.11.4.min',
        'promise': 'libs/es6-promise/promise-1.0.0.min',
        'hammerjs': 'libs/hammer/hammer-2.0.4.min',
        'ojdnd': 'libs/dnd-polyfill/dnd-polyfill-1.0.0.min',
        'ojs': 'libs/oj/v1.1.2/min',
        'ojL10n': 'libs/oj/v1.1.2/ojL10n',
        'ojtranslations': 'libs/oj/v1.1.2/resources',
        'signals': 'libs/js-signals/signals.min',
        'text': 'libs/require/text'
    shim: {
        'jquery': {
            exports: ['jQuery', '$']
        'crossroads': {
            deps: ['signals'],
            exports: 'crossroads'
    config: {
        ojL10n: {
            merge: {
                //'ojtranslations/nls/ojtranslations': 'resources/nls/menu'

        function(oj, ko, $, app)
            var vm = new app.contactsVM();
                ko.applyBindings(vm, document.getElementById('mainContent'));

                //Show the content div after the REST call is completed.

and app.js

define(['ojs/ojcore', 'knockout', 'ojs/ojmodel'],
       function(oj, ko)
           function viewModel()
                var self = this;
                self.serviceURL =
                self.dataSource = ko.observable();
                self.ContactsCollection = ko.observable();
                self.myBasicAuth = function() {};
                self.myBasicAuth.prototype.getHeader = function ()
                    var headers = {};
                    headers['Authorization'] = 'Basic ' + btoa("admin:admin");
                    return headers;
                parseContact = function(response)
                    return {ID: response['ID'],
                            FIRSTNAME: response['FIRSTNAME'],

                var Contact = oj.Model.extend(
                    urlRoot: self.serviceURL,
                    parse: parseContact,
                    idAttribute: 'ID'
                var myContact = new Contact();
                var ContactsCollection = oj.Collection.extend(
                    url: self.serviceURL,
                    model: myContact,
                    oauth: new self.myBasicAuth(),
                    comparator: "ID"
                self.ContactsCollection(new ContactsCollection());
                //simple Request test
                //self.ContactsCollection().fetch({headers: {"Authorization": 'Basic ' + btoa("admin:admin")}});
                self.dataSource(new oj.CollectionTableDataSource(self.ContactsCollection()));      

           return {'contactsVM': viewModel};

Above files are not enough to run the example because you need a full JET application. You can download a JET application from the official site (-> Getting started with Oracle JET -> Downloading Oracle JET). The QuickStart template works well. Unzip the application into the directory: <VisionX_folder>/rad/apps/visionx/WebContent/ojet (ojet must be created manually). Simply copy the example files in the ojet, ojet/js folder.
Open the browser and navigate to: http://localhost/ojet/

My source code is small and simple but I don't know if it could be optimized. The official CRUD example application has more features and doesn't connect to a real REST service.
It wasn't funny to use/read the example because it's much for such a simple use-case. I found a similar but inofficial example. This was nice but didn't solve the Basic authentication problem!

Long story, short:

I found no option for Basic authentication and no documentation, but found that OAuth is supported. Not the same as Basic authentication but something I could search in the source code. The Model file was the right place to search (-> oauth).

And my simple solution for Basic authentication was:

self.myBasicAuth = function() {};
self.myBasicAuth.prototype.getHeader = function ()
  var headers = {};
  headers['Authorization'] = 'Basic ' + btoa("admin:admin");
  return headers;

Username and password are hardcoded, but it's easy to replace the code with a better solution.

The "authenticator" will be set as oauth property:

var ContactsCollection = oj.Collection.extend(
    url: self.serviceURL,
    model: myContact,
    oauth: new self.myBasicAuth(),
    comparator: "ID"

The problem with this API is that it's not guaranteed that the getHeader method will be used in future releases. And it's also not perfect to use oauth for Basic authentication, but whatever.

Our example runs with VisionX' embedded tomcat. If you want to test with your own application server, you should enable CORS for VisionX to use the REST services from an external server:

To enable CORS, change the web.xml in <VisionX_folder>/conf/ and add


to RestletServlet definition.

Example Download

Use OBridge together with JVx

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OBridge is a nice Java FOSS project. The description according to the website:

OBridge generates standard Java source code for calling PL/SQL stored procedures and functions.

It's focus is on Oracle but this wasn't a limitation for us to test it with JVx.

Most of you know that JVx has generic support for procedure/function calls which is DB independent. The implementation is not really type-safe but it's simple.
If type-safety is preferred, you could use OBridge for your application.

I write about this library, because it's super small and simple. We love small and simple things :)

Assume, we have following PL/Sql procedure:

                                          pInText IN VARCHAR2,
                                          pOutText OUT VARCHAR2) IS
  nr NUMBER := pNumber;
  pOutText := 'Out: '|| pOutText ||' In: '|| pInText;

  pNumber := pNumber + pNumber;
END execProcedure;

and function:

                                        pInText IN VARCHAR2,
                                        pOutText OUT VARCHAR2) RETURN VARCHAR2 IS
  res VARCHAR2(200);
  nr NUMBER := pNumber;
  pOutText := 'Out: '|| pOutText ||' In: '|| pInText;

  pNumber := pNumber + pNumber;

  RETURN 'IN-Param Nr: '|| nr;
END execFunction;


With JVx, the procedure and function call will look like following JUnit test:

public void testCall() throws Exception
    DBAccess dba = DBAccess.getDBAccess("jdbc:oracle:thin:@localhost:xe", "test", "test");;
     * Procedure call.

    OutParam ouTextParam = new OutParam(InOutParam.SQLTYPE_VARCHAR);
    dba.executeProcedure("execProcedure", BigDecimal.valueOf(25),
                         "Hello JVx' procedure", ouTextParam);

    Assert.assertEquals("Out:  In: Hello JVx' procedure", ouTextParam.getValue());

     * Function call.

    ouTextParam = new OutParam(InOutParam.SQLTYPE_VARCHAR);
    Object oResult = dba.executeFunction("execFunction", Types.VARCHAR,
                                         "Hello JVx' function", ouTextParam);
    Assert.assertEquals("IN-Param Nr: 25", oResult);
    Assert.assertEquals("Out:  In: Hello JVx' function", ouTextParam.getValue());


and the same with OBridge:

public void testCall() throws Exception
    DBAccess dba = DBAccess.getDBAccess("jdbc:oracle:thin:@localhost:1521:xe", "test", "test");;
     * Procedure call.

    Execprocedure proc = ProceduresAndFunctions.execprocedure(BigDecimal.valueOf(35),
                                           "Hello OBridge procedure", dba.getConnection());
    Assert.assertEquals("Out:  In: Hello OBridge procedure", proc.getPouttext());

     * Function call.

    Execfunction func = ProceduresAndFunctions.execfunction(BigDecimal.valueOf(35),
                                            "Hello OBridge function", dba.getConnection());
    Assert.assertEquals("IN-Param Nr: 35", func.getFunctionReturn());
    Assert.assertEquals("Out:  In: Hello OBridge function", func.getPouttext());


The OBridge code saves two LoC for the call, but it needs some additional classes and packages in your application. If you change your procedure or function definition in the database, you have to recreate the Java files.
This is not needed with pure JVx, but it's your choice.

The code generation is not tricky, simply follow the official documentation. Our steps:

  • Create the file config.xml in the working directory of your project
    <?xml version="1.0" encoding="UTF-8"?>


  • Run the main class: org.obridge.OBridge with argument: -c config.xml
    (or use -c fullqualified_path_to_config.xml)

If you love our generic built-in solution, you don't need OBridge but if you prefer type-safety it's definitely an option.

RaspberryPi + 1-wire + i2c + camera and kernel pain

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Our last research project was real fun: Build a Webcam with temp and light sensor to do some home/office automation.

We took a RaspberryPi model B, temp sensor (DS18B20) and light sensor (TSL45315).

The temp sensor had a 1-wire interface and the Internet had many tutorials to connect the sensor to a RasPi. It should be a trivial job, if you read the tutorials and it should be ready in max. 10 minutes. Should!

The theory wasn't the reality and the tutorials didn't cover our environment, because we had a new Raspbian ISO with kernel 3.16 and 3.18 some hours later.

We tried to connect the sensor as described (with and without pullup resistor, with parasite power and without) but it wasn't detected. It was horrible because the driver was loaded without problems and logged a simple success message.
We didn't find information about the problem because we didn't see an error. It simply did nothing and the filesystem didn't contain the relevant files and directories. Our /sys/bus/w1/devices directory was clean and empty. After some hours error searching, without any ideas we tried an older Raspbian image with kernel 3.6 and our sensor worked out-of-the-box without modifications. We saw additional log information from the 1-wire module which we didn't have with our 3.18 kernel. So we knew that something has changed in the kernel or kernel config...

But we weren't happy because the whole thing should work with an up-to-date setup. After we knew that the kernel caused our problems, we tried to find a solution and found: (first posting on 2nd page). There was a hint about the device tree. With this information, we found:

We disabled the device-tree by adding device_tree= to our config.txt and everything worked after a reboot, with our 3.18 kernel. So far so good.

It also worked with device_tree_overlay=overlays/w1-gpio-overlay.dtb. This option was our preferred one because it didn't disable the device_tree.

After our temp sensor worked without problems we connected the Raspicam and made some tests. Everything worked without problems. The last piece of our project was the light sensor. It was a littly bit tricky to use the sensor with our Pi because the source code example wasn't available for Java/Pi4J, but here it is:

I2CBus bus = I2CFactory.getInstance(I2CBus.BUS_1);

I2CDevice device = bus.getDevice(0x29);

device.write((byte)(0x80 | 0x0A));

byte[] byData = new byte[1];, 0, 1);


System.out.println("Power on...");

device.write((byte)(0x80 | 0x00));


device.write((byte)(0x80 | 0x01));
device.write((byte)0x00);   //M=1, T=400ms
//device.write((byte)0x01);   //M=2, T=200ms
//device.write((byte)0x02);   //M=4, T=100ms

byData = new byte[2];

while (true)
    device.write((byte)(0x80 | 0x04));, 0, 2);
    int l = byData[0] & 0xFF;
    int h = byData[1] & 0xFF;
    int lux = (h << 8) | (l << 0);
    lux *= 1;   //M1
    //lux *= 2;   //M2
    //lux *= 4;   //M4

We compared the output with an Arduino board and the values were "the same".

It wasn't possible to use the light sensor without required modules. We simply added device_tree_param=i2c1=on to our config.txt and I2C worked. You should install

sudo apt-get install i2c-tools

to verify connected sensors, via:

i2cdetect -y 1

After we thought that everything will work, we put all pieces together: temp sensor, cam, light sensor.
During development, we didn't use all parts together - only the relevant sensor, to rule out errors.

Everything worked fine after starting the Pi, but the cam stopped capturing after some minutes... frustrating.
So again we tried to find an error without detailed information and without logs. We thought it might be a module loading problem and found some hints: But nothing worked for us. The only working solution was: disable the device tree :(

The whole system is up and running for some days and there we no problems.

We currently don't know what's the problem with the device tree or what we should configure to avoid problems, but if you have similar problems, this posting could help. If you have a working solution with the device tree... leave a comment :)

Vaadin UI with SmartTV

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It's not rocket science and we didn't write code, but it's nice to see our UIs on SmartTVs :)

Here are some impressions:

SmartTV - Statistic

SmartTV - Statistic

SmartTV - Data

SmartTV - Data

SmartTV - Window Shutter

SmartTV - Window Shutter

Window shutter UI - WiiU

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Because I got some emails, here's the window shutter UI how it looks on my Wii U. Sure, the space is not perfectly used, but the UI wasn't optimized for Wii U. Also the agent name of the browser wasn't checked to optimize controls.

But it's ok and control just works :)

The pictures (phone cam):

Wii-U controller

Wii-U controller

Wii-U (TV)

Wii-U (TV)