Robert Jan van Holland

DB4O continued...

Robert Jan van Holland — Thu, 23 Jun 2005 12:35:00 GMT

Ernst triggered me to spend some more time on the DB4O web site.

On that site I found a very good whitepaper of Rick Grehan explaining some aspects of DB4O and persistence solutions.

A comment on the whitepaper:
In this whitepaper, Rick Grehan explores the issue of complexity in object-oriented programming and how persistence solutions cope with it. He distinguishes flat, complex, and dynamic object models.
Grehan discovers that "db4o lets you work with object structures almost as though they were 'in-memory' structures. Little additional coding is required to manage object persistence." He also proves that "as the persistence requirements become more complex, db4o's unique design takes care of the added complexity, so you can continue to work as though that complexity were never introduced."

I think everybody who is interested in this subject should read this. You can find it here.

So as a summary, the following two principles about DB4O are mentioned :

db4o lets you work with object structures
almost as though they were "in memory" structures.
Little additional coding is required to manage object persistence.

As the persistence requirements become more complex,
db4o’s unique design takes care of the added complexity
so you can continue to work
as though that complexity never happened.

Isn't this wat we all want?!?

Let's keep in touch!

Robert Jan van Holland — Tue, 21 Jun 2005 07:46:00 GMT

We just have to wait 10 days, and then we'll go on a hopefully beautiful holiday; the whole month of july we will be in de USA.
(so no TechEd in Amsterdam for me this year :( )
At first we will visit the city of New York and after a few days we will take a flight to Las Vegas.
There will be a camper waiting for us which will take us through many national parks in that environment.

The route we will drive will be :

(click for larger version)

The parks we will visit :

- Grand Canyon (wikipedia)
- Navajo National Monument (wikipedia)
- Arches (wikipedia)
- Badlands (wikipedia)
- Bryce Canyon (wikipedia)
- Canyonlands (wikipedia)
- Capitol Reef (wikipedia)
- Zion (wikipedia)
- Death Valley (wikipedia)
- Yosemite (wikipedia)

Then we will drive to the west coast where we will arrive above Los Angeles. There we will take highway one and drive to the north to San Francisco.
Off course we will visit Alcatraz.

I'll try to keep up a moblog at http://vanholland.net/amerika (in dutch, sorry :) ). To accomplish this, I need to sent emails from my mobile phone to a mailbox so I need to have GPRS coverage; as I don't know how good that coverage is in the States, I cannot say how many updates there will be. But hey!, I'll do my best.
Expect the first update on our departure from Amsterdam :)

For you guys who have been to New York or the West Coast, what should we definitely see and what should we skip?

Suggestions are more ~~then~~ than welcome!

P.S. Man, still have to wait ten days..... counting down.... :)

XBOX 360 Revealed...

Robert Jan van Holland — Fri, 13 May 2005 09:28:00 GMT

As some of you know, I am a BIG fan of the XBOX. Right now I spend a lot of time playing Jade Empire.. That game rocks!
But today, the next Microsoft console called XBOX 360 has been revealed on MTV.
For us in Holland the show is planned on 19:30 tonight on MTV. Some people say the show isn't really worth watching; not much in-game footage and not much interesting details. We'll see. Some live footage from the show can be seen at http://www.engadget.com/entry/1234000617043196/.

I just saw this small movie : http://msxb.wmod.llnwd.net/a274/o2/ourcolony/TheColony_v1_750k.wmv. It highlights some really nice features of the XBOX 360, and I must say, it really looks promising! I can hardly wait till it's for sale here.
The official XBOX 360 site has also been launched : http://www.xbox360.com

A complete list of specs can be found here : http://www.gamer.nl/viewdoc/1746

Bloggie 2.0 : Soon a new Visual Studio 2005 / .NET 2.0 version

Robert Jan van Holland — Mon, 02 May 2005 20:42:00 GMT

It has been a while since there was news about Bloggie. Well, time didn't stand still, that's for sure.
Besides Blogggie I have been busy with all sorts of things, from private to professional subjects.

But there is news! Which is, that currently I am making some very good progress with Bloggie 2.0 : the next version of
my weblog desktop client written completely in c# . But this version has some changes.

Most importantly, this version is written using the .NET framework 2.0 (currently beta 2) and build in Visual Studio 2005 (currently beta 2).
But Bloggie has also evolved a bit further. FTP and offline support, threading and a brand new user interface.

More news will follow shortly, but for now, here are some screen shots of Bloggie 2.0 :

(Click for larger images)

I say, let's split the profit :)

Robert Jan van Holland — Wed, 13 Apr 2005 13:42:00 GMT

I saw this link in some post on the internet https://www.lastdeveloper.com/

One 4 all, all 4 one? :)

I have registered myself already... now let's wait for the 2nd of may

Public release beta Bloggie!

Robert Jan van Holland — Sun, 03 Apr 2005 18:14:00 GMT

After a lot of work, I am proud to announce this public beta release of Bloggie.
I would like to invite you all to download the MSI setup at : http://bloggie.vanholland.net/download.aspx?fn=BloggieSetup.msi and test it out!

Try every option out and supply me with your remarks / bugs / change requests at http://bloggie.vanholland.net/FlySpray
Remember, Bloggie is build in my own time and is freeware.

Known issues are :
- not everything is translated yet
- "Edit Last Post" does not work yet
- for now, only 3 weblog types are supported
- Graphics are certainly not final :)
- ... some minor bugs...

The official features list of Bloggie 1.0 is :

Supports multiple weblogs
Supports multiple languages
Spell Checker
10 dictionaries for spell checking
WYSIWYG editor
Source code formatter
Syntax highlighting
HTML intellisense
Automatically upload local referred files to a specified FTP server
Statistics
Blog site browser
Add, View, Edit & Delete posts
Print post
Save and Open posts as drafts

Native Objects - Persistance Layer Generator

Robert Jan van Holland — Fri, 11 Mar 2005 15:37:00 GMT

The last two weeks I have been looking into DB4O's object database.
I really wanted to do someting with it and thought why not create something generic to generate a persistance layer for business objects.

Wouldn't it be nice if you would just create your object oriented business layer and generate some object oriented persistance layer so objects can be stored and retrieved with real ease? This persistance layer doesn's have to be the final persistance layer; during development it can sometimes be a hazzle to create and maintain tables, stored procedures and data layer classes. What if we could use a tool which would look into your business DLL's and generate an assembly with persistance and retrieval methods for those objects and would delegate that persistance to DB4O?

First a note... this application is a personal project and in a test phase. Normally this tool is meant for personal, non-commercial use only. If you do want to use this tool otherwise, contact me and DB4O. DB4O deserves credits and payments for their software when used commercially. So if you intend to use this that way, buy sufficient licenses for DB4O.

Okay, let's continue..

Lets have a simple class model with 3 classes (Customer, Order and Product). Our generator will use System.Reflection to look into the classes in your business DLL and simply create a Persist method for each class it encounters. This persist method will take care of storing the object in DB4O.

Then, the generator will examine which private fields are available on the class. It will generate a RetrieveBy method for every private field it encounters. Because I couldn't find out if and how DB4O is capable of retrieving objects using public properties, for now the generator uses the private fields.

So this is simply what it does... how do you use it?
First download the generator here. It contains the .EXE and the DB4O 4.3 dll.
Well, the generator is simply a console application. For the above example I have built a VS.NET 2003 project which is available here. It contains the three classes but there is something you have to take a look at. If you look in the project properties , Common Properties and then Build Events, you can see that there is a Post-Build Event supplied. It contains :

C:\temp\nofgen.exe /o:"c:\temp" /s /a:"$(TargetPath)"

So, put the generator in c:\temp (or adjust this post build event). The $(TargetPath) just points to the DLL built by this project. This is great, don't you think!? Create (and update) a persistance layer every time you build the business layer?....
The /o argument means the outputpath, /s means it should also generate a source code file and the /a targets the business dll.

Off course, it is also possible to run the generator as a stand alone console application :

If the build was succesfull, you will find a DLL called 'NOFPersistanceLayer.dll' in the Bin directory in the supplied output folder.
You can reference this DLL from your application to utilize the persist and retrieval methods :

 1: NOFGenTestLibrary.Customer c = new NOFGenTestLibrary.Customer("Robert Jan");

 2: NOFPersistanceLayer.Customer.Persist(c);

 3: NOFGenTestLibrary.Customer[] temp = NOFPersistanceLayer.Customer.RetrieveBy_name("Robert Jan");

First this will create an instance of a Customer with the name 'Robert Jan'. Then, it will call the persist method in the generated assembly to store this instance. Afterwards, the retrieval method 'by name' is used to retrieve all Customers with the name 'Robert Jan'.
Cool isn't it?

I am really interested in your opinions and suggestions.. is this usefull or not? what else do you think it should or shouldn't do? let me know!..

Bloggie : 1.0 Beta released for testers!

Robert Jan van Holland — Wed, 02 Mar 2005 12:17:00 GMT

Great news!
After a LOT of work I am proud to let you know a first beta version of Bloggie has been released.
For now, only two testers (Dennis van der Stelt and Edward Bakker) are provided with this version and will hopefully provide me with lots of information to make it bugfree (as far as that is possible off course :)). I don't know yet how much time it will consume to create a rather bugfree version, but I'll release the first Alpha as soon as possible.

This version has the following known issues :

Uploading local files is not working
Not all forms are translatable
"Edit last post" does not work
"Statistics" does not work
"Online Help" does not work
Exceptions don't have a "nice-user-readable" message
...some minor...

If you want to spend some time on testing, let me know. I'm thinking of letting 2-3 other people test Bloggie.
Testers, please provide me with detailed issue information by email, or as comment in this post.

The official features list of Bloggie 1.0 is :

Supports multiple weblogs
Supports multiple languages
Spell Checker
10 dictionaries for spell checking
WYSIWYG editor
Source code formatter
Syntax highlighting
HTML intellisense
Automatically upload local referred files to a specified FTP server
Statistics
Blog site browser
Add, View, Edit & Delete posts
Print post
Save and Open posts as drafts

This list will be updated if necessary.

Native Objects Database

Robert Jan van Holland — Tue, 01 Mar 2005 09:28:00 GMT

Yesterday I was browsing on the net searching for some solutions for challenges I currently have to cope with while working on my hobby projects; for example Bloggie. I wanted a simple storage mechanism where no client/server model is necessary. I preferred something for storing my objects so that no mapping to whataver relational model is needed.
So I came accross this website : http://www.db4o.com/about/productinformation/

They have implemented a native object database mechanism that really caught my attention. I think it is really very cool to just store your objects in some way without the need of conterting / mapping it to some flat relational database model.
So I downloaded it and wrote a little test to see it work (see below).
How it works behind the scenes? I dont know... Performance? I dont know either...

But it does support query by example, cascading updates/deletes, transactions and a client/server model.
I dont think any reporting service will interact with this technique yet, so that is a drawback; but I see some really positive possibilities for standalone applications and small n-tier apps.

I think I'll dig in this product some more...
But i'm really curious what you guys think of this product? what drawbacks do you see? Let me know...

Addition :
The developers have a weblog at http://www.people4objects.org/
A nice quote from this blog :
"This has nothing to do with scripting, but I stumbled across this very interesting OO database recently. db4objects a GNU licensed object database that has native Java and .Net interfaces. You can basically give it any object and it will store it for you with a single line of code. You can do pretty complex queries to get data out of it. Essentially, it returns lists of objects based on filters on the pool of objects it has stored. You can filter on class, any field value, and so sorting and that sort of thing. It has both internal and server-based modes, and I imagine it could be made transactional with any of the framework-based transaction engines. With a little rethinking of the persistence layer, this could save a lot of coding time in Java/.Net programs - no more database schema management, no more SQL insert, update, and delete statements."

To run this example... Download the package from their website... start a new c# windows app and add a reference to the downloaded dll “db4o.dll”.
Make sure you have a c:\temp directory because there your db container will be written to, or change the file path.
Copy paste this source first to wordpad and then in your form1.cs and run the app.

using System;

using System.Drawing;

using System.Collections;

using System.ComponentModel;

using System.Windows.Forms;

using System.Data;

using com.db4o;

using com.db4o.query;

namespace db4otest

///

    /// Summary description for Form1.

///

    public class Form1 : System.Windows.Forms.Form

///

        /// Required designer variable.

///

        private System.ComponentModel.Container components = null;

        private System.Windows.Forms.Button button1;

        private System.Windows.Forms.Button button2;

        private System.Windows.Forms.Button button3;

        private System.Windows.Forms.Button button4;

        private System.Windows.Forms.Button button5;

        string filepath = @"c:\temp\db4o.db";

        public Form1()

//

            // Required for Windows Form Designer support

//

            InitializeComponent();

//

            // TODO: Add any constructor code after InitializeComponent call

//

///

        /// Clean up any resources being used.

///

        protected override void Dispose( bool disposing )

            if( disposing )

                if (components != null)

                    components.Dispose();

            base.Dispose( disposing );

        #region Windows Form Designer generated code

///

        /// Required method for Designer support - do not modify

        /// the contents of this method with the code editor.

///

        private void InitializeComponent()

            this.button1 = new System.Windows.Forms.Button();

            this.button2 = new System.Windows.Forms.Button();

            this.button3 = new System.Windows.Forms.Button();

            this.button4 = new System.Windows.Forms.Button();

            this.button5 = new System.Windows.Forms.Button();

            this.SuspendLayout();

//

            // button1

//

            this.button1.Location = new System.Drawing.Point(24, 16);

            this.button1.Name = "button1";

            this.button1.Size = new System.Drawing.Size(104, 23);

            this.button1.TabIndex = 0;

            this.button1.Text = "AddRJ";

            this.button1.Click += new System.EventHandler(this.button1_Click);

//

            // button2

//

            this.button2.Location = new System.Drawing.Point(24, 64);

            this.button2.Name = "button2";

            this.button2.Size = new System.Drawing.Size(104, 23);

            this.button2.TabIndex = 1;

            this.button2.Text = "ShowNumber";

            this.button2.Click += new System.EventHandler(this.button2_Click);

//

            // button3

//

            this.button3.Location = new System.Drawing.Point(24, 88);

            this.button3.Name = "button3";

            this.button3.Size = new System.Drawing.Size(104, 23);

            this.button3.TabIndex = 2;

            this.button3.Text = "QueryForRJ";

            this.button3.Click += new System.EventHandler(this.button3_Click);

//

            // button4

//

            this.button4.Location = new System.Drawing.Point(24, 112);

            this.button4.Name = "button4";

            this.button4.Size = new System.Drawing.Size(104, 23);

            this.button4.TabIndex = 3;

            this.button4.Text = "Clear DB";

            this.button4.Click += new System.EventHandler(this.button4_Click);

//

            // button5

//

            this.button5.Location = new System.Drawing.Point(24, 40);

            this.button5.Name = "button5";

            this.button5.Size = new System.Drawing.Size(104, 23);

            this.button5.TabIndex = 4;

            this.button5.Text = "AddDennis";

            this.button5.Click += new System.EventHandler(this.button5_Click);

//

            // Form1

//

            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);

            this.ClientSize = new System.Drawing.Size(144, 149);

            this.Controls.AddRange(new System.Windows.Forms.Control[] {

                                                                          this.button5,

                                                                          this.button4,

                                                                          this.button3,

                                                                          this.button2,

                                                                          this.button1});

            this.Name = "Form1";

            this.Text = "Form1";

            this.ResumeLayout(false);

        #endregion

///

        /// The main entry point for the application.

///

        [STAThread]

        static void Main()

            Application.Run(new Form1());

        private void button1_Click(object sender, System.EventArgs e)

            ObjectContainer db = Db4o.openFile(filepath);

try

                Account a = new Account("RJ","rj@rj.net",@"http://vanholland.net");

                db.set(a);

            finally

                db.close();

        private void button2_Click(object sender, System.EventArgs e)

            ObjectContainer db = Db4o.openFile(filepath);

try

                Account proto = new Account(null,null,null);

                ObjectSet result = db.get(proto);

                MessageBox.Show(result.size().ToString());

            finally

                db.close();

        private void button4_Click(object sender, System.EventArgs e)

            ObjectContainer db = Db4o.openFile(filepath);

            ObjectSet result = db.get(new Account(null, null,null));

            while (result.hasNext())

                db.delete(result.next());

            db.close();

        private void button3_Click(object sender, System.EventArgs e)

            ObjectContainer db = Db4o.openFile(filepath);

            Query query = db.query();

            query.constrain(typeof(Account));

            query.descend("_name").constrain("RJ");

            ObjectSet result = query.execute();

            for (int i =0; i            {
                if (result.hasNext())
                {
                    Account a = (Account)result.next();
                    
                    MessageBox.Show(a.Name);
                }
                else
                {
                    break;
                }
 
            }
            db.close();
        }
 
        private void button5_Click(object sender, System.EventArgs e)
        {
            ObjectContainer db = Db4o.openFile(filepath);
            try
            {
                Account a = new Account("Dennis","Dennis@dennis.com",@"http://dennis.net");
                db.set(a);
                
            }
            finally
            {
                db.close();
            }
        }
    }
 
    public class Account
    {
        string _name;
        string _emailadres;
        string _url;
 
        public Account(string name, string emailadres, string url)
        {
            _name = name;
            _emailadres = emailadres;
            _url = url;
        }
 
        public string Name
        {
            get
            {
                return _name;
            }
        }
 
        public string EmailAdres
        {
            get
            {
                return _emailadres;
            }
        }
 
        public string URL
        {
            get
            {
                return _url;
            }
        }
    }
}

Internet Direct - multiple protocols implemented in one library

Robert Jan van Holland — Mon, 28 Feb 2005 09:37:00 GMT

I was looking for some sort of library which implements at least the ftp protocol. I was surprised to find the following :

http://www.indyproject.org/download/DotNet.iwp

A great class which has build in clients and servers for ftp, http, smtp, nntp, tcp, udp, pop3, imap4 and lots more... and for FREE! The PDF documention is of an impressing 10MB size.
Also threading, email, encrpyting, decrypting, compression and hashing is supported.

See for yourself... I'm gonna use this one for sure..

OPML blog roll : Dutch .NET Developers Alliance

Robert Jan van Holland — Fri, 11 Feb 2005 11:56:00 GMT

It has been around for a while now; I haven't noticed it, but I know Dennis has it in his blog client for a while now!
What I talking about?! Perhaps you have seen this, and you're already using it, but if not :

A dutch developers blog collection in one OPML file maintained by Paul Gielens! Just import this in your favourite blog tool and you have a nice list with experts (at least I think that's what it should be:))

You can always download the OPML file here!

I am not on the list yet, but I will send Paul an email with my request and so can you (if you are dutch and a .NET developer off course)!

The last update about this list can be read here.

Conflict in ASP.NET between 1.1 and 2.0

Robert Jan van Holland — Fri, 21 Jan 2005 19:59:00 GMT

Today I installed DasBlog on my laptop to be able to test Bloggie with it. After installing the DasBlog package I fired up the main page and got :

a big. fat. annoying error which said that the process couldn't find / didn't have access to the System.Web dll with version 2.0.someotherfigures.
I thought : hey!?! Why does my DasBlog binaray package compiled with the 1.1. framework is trying to use framework 2.0.

So after a short search I found on MSDN : http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cptools/html/cpgrfASPNETIISRegistrationToolAspnet_regiisexe.asp

The -r option will update all script maps to use the correct asp.net version (in my case 1.1)
and after I exectued “aspnet_regiis -r” everything worked like a charm again!

ps : this post has been submitted by Bloggie :)

Bloggie : Sources & Progress Update

Robert Jan van Holland — Fri, 21 Jan 2005 09:56:00 GMT

Yesterday I decided not use use the GotDotNet source control any more. This is because of a terrible performance I get from within Visual Studio.NET when checking in and out source files. It just takes too much time.
So since yesterday sources are held in Source Safe and are accessible over the internet by a nice source control add-in.
Progress is slow (but steady :)). One of my resolutions for this new year was to invest some more time in these kind of projects; I'll guess this resolution will get fullfilled soon.

I installed visual studio 2005 CTP (december) and converted the sources. But really, it is too beta to use it already. The form designer gave some exceptions and wouldn't show me the design mode any more. Even if I started a brand new Windows Forms project, and I added a brand new empty Windows Form, closed the solution and then opened it again, this annoying exception occured. This was not a workable situation so I stick to VS.NET 2003 and will migrate to 2005 as soon as it proves to be a steady environment (hopefully a CTP of january or february).

Bloggie : progress update

Robert Jan van Holland — Fri, 31 Dec 2004 08:53:00 GMT

My router died last week.. so checking in new sources was a bit hard for me... But I just bought a new router and development of Bloggie is still going on, and next year (*grin*) I'll check in the newest sources.. Expect it somewhere on the 2nd january.

What I'm doing right now?
Well, Bloglib (thus also XML-RPC.NET) is integrated and and some interaction with .Text and Wordpress is possible. As different blogs use different blog api's the implementation of each blog in Bloggie should be as generic as possible. Right now, xml files specify what method's a blog is supporting and Bloggie adjusts to that by calling methods on the right Bloglib interface and dynamically supplying it with the right parameters. So this means that I have to check every blog and create a xml file which defines the supported blog api methods.
For now, I'll only concentrate on .Text and Wordpress.

Further, I'm having a hard time finding the right user interface. I'm altering/shifting/moving controls all over the screen, but I still haven't found the GUI I want.
I am also integrating the c# code format tool from Jean-Claude Manoli, so sources can be converted nice to HTML. Due to all sorts off activities progress is stable, but not fast. I'll keep you in touch!

More news next year, and for now :

A very, very happy new year to you all!!!

Fancy Windows forms continued...

Robert Jan van Holland — Thu, 23 Dec 2004 09:56:00 GMT

In my post of the 14th of december I revealed two possibilities to make your windows form not so boring square. Well, instead of an image describing the shape and looks of your form, why not draw it yourself using GDI+?

Today, a new article was posted on CodeProject which describes just that! Have a look, and start drawing your own forms!