Wallpaper Generator

A nice WPF application that creates a wallpaper based on a photo folder.

Download the application from here.

FlowDocument and multiple threads

Recently, I try to use the FlowDocumentScrollViewer to display FlowDocument's. So I create WPF window application that creates and displays flow documents with FlowDocumentScrollViewer.





The refresh button clears the contents of the documentPanel, and creates and displays a random number of flow documents.





This works as expected and creates a random number of flow documents on window.
My next step is to make this work in asynchronous manner. How is that possible? Enter DispatcherObject and WPF Threading model.
The basic technique is to use the Dispatcher methods and delegates to do the heavy operations in a different thread.
To demonstrate this, I create a new "Refresh Async" button and modify the flow document creation to include a 5 sec Sleep.
The next step is to add the delegate and dispatcher calls. The refresh async button handler uses the Dispatcher to asynchronously call the GenerateAndShowFlowDocumentHandler method which creates and displays the flow document.







This also works fine.

The next step is to create the FlowDocument in a separete thread and use the main UI thread for UI update.





When I try this I get exceptions!.








To resolve this issue, I should serialize the FlowDocument as Memory stream since FlowDocument's seems that they can’t serialize themselves on different threads.
Add the following before passing the flow document.









And to the handler :





And it works great!!

The fastest Windows Vista notebook is a MacBook Pro !!!!

Watch the Ad: http://www.apple.com/getamac/ads/

More on Vista's File Copy

Guess how much time it will take to extract a zipped file of about 5MB to a disk using Vista's extract feature?

How to port SQL Server OPENXML to Oracle PL/SQL

If you want to port code that contain OPENXML calls from SQL Server to Oracle, you will find that there is no such call. OPENXML works with sp_xml_preparedocument and xp_xml_removedocument calls to produce (among other things) a relational table based on XML document.



In my case, I use the XML document to pass an array of primary keys, use them as a filter for a table and join and return them.



For example suppose an application based on SQL Server TSQL has:

A table "BRANDS" contain a BRAND_ID (INT) and a TITLE (VARCHAR)

such as:

BRAND_ID TITLE

1 Nokia

2 Siemens

3 Other

4 IBM

5 HP



A stored procedure GET_BRAND_LIST as:

CREATE PROCEDURE dbo.GET_BRAND_LIST(@IDLIST NTEXT )

AS

DECLARE @hDoc int

EXEC sp_xml_preparedocument @hDoc OUTPUT, @IDLIST


SELECT BRAND_ID, TITLE FROM BRANDS

INNER JOIN OPENXML (@hDoc, '/s/k',2) WITH (I int) AS ResultSet

ON BRANDS.BRAND_ID = ResultSet.I



EXEC sp_xml_removedocument @hDoc

RETURN



GO



And an XML input similar to:


where:

• s is the root element




• k specifies a primary key and




• I the value of the primary key

such as:




calling GET_BRAND_LIST will return the brands with BRAND_ID equal to 1, 3 and 4.





Here is how to do the same in Oracle:

• Use CBLOB instead on NTEXT to pass the XML value.




• Use XMLType instead on sp_xml_preparedocument and sp_xml_removedocument calls.




• Use XMLSequence to convert and create a temporary table filled with the primary keys.




• Use EXTRACT to get the primary key value to perform the Join.

The complete Oracle code:
PROCEDURE GET_BRAND_LIST (cur_OUT OUT T_CURSOR, pIDLIST CLOB)
IS
anXmlType XmlType;
V_CURSOR T_CURSOR;
BEGIN
anXmlType := XmlType(pIDLIST);
OPEN V_CURSOR FOR
SELECT BRANDS.BRAND_ID, BRANDS.TITLE
FROM BRANDS,
table(XMLSequence(extract(anXMLType, '/s/k/*'))) ResultSet
WHERE BRANDS.BRAND_ID = TO_NUMBER(EXTRACT(value(ResultSet), 'I/text()'));



cur_OUT := V_CURSOR;
END;

Vista and File Copy

The Antikythera Mechanism Research Project

The Antikythera Mechanism is an ancient astronomical computer built by the Greeks around 80 B.C. It was found on a shipwreck by sponge divers in 1900, and its exact function still eludes scholars to this day.

Game Innovation Database.

Do you remember "Shadow of the Beast"? Lemmings? probably YES...If you are a fan of computer games.

Well, GIdb goal is to classify and record every innovation in the entire history of computer and videogames.

Five Years of Design

Martin Fowler writes about the articles of the past five years of IEEE Software “Design” section, before passing the editing of the section to Rebecca Wirfs-Brock. This last article explains the basic Design Principles, the derived Best-Practices and their role in the software development process.

Thanks Martin.

Development (Print) magazines are disappearing…

CMP Media has recently “merge” two of the most known software development magazines; Software Development and the C++ Users Journal (one of the last magazines dedicated to C/C+) into Dr. Dobbs magazine. Fortunately, I have an active subscription to Dr. Dobbs and I won’t lose any subscription fees.
Several years ago, CMP has also ceased the publication of the “legendary” BYTE magazine which makes me very angry (back in 1998) because a valuable source of information has been lost.

Obviously big publishing companies began to realize the importance of getting all the information directly from the provider using its blog, from a Usenet forum, or from a web site found be Google Search, and they make major efforts to create software development portals to replace the gap.

The difference is obvious.

A Brief Look at C++0x

Bjarne offers a sneak peek at the next version of standard C++ ("C++0x") which should be complete by 2009.

Do you know Al-Khowarizmi?

According to Knuth (you should know Knuth), the word "Algorithm" is derived from the name Al-khowarizmi, a ninth-century Persian mathematician.

Embrace change.

Are you trying to learn new things constantly?
Do you embrace change in your life?

Computer History Museum

On April 7 of 1969, Steve Crocker sends around a memo entitled ‘Request for Comments.’ This is the first of thousands of RFCs that document the design of the ARPANET and the Internet.

Architecture of the World Wide Web

Computer Pioneer Bob Bemer Passes Away

Who was Bob Bemer:
* the 'father or ASCII' character set.
* the 'grandfather' of COBOL.
* the inventor of ESCAPE and BACKSLASH sequences.
* the man behind the '8-bit' byte standardization.
* a pioneer in 3-D dynamic prespective.

Bob Bemer was awarded by IEEE Computer Society with the Computer Pioneer Award.

Do you remember this machines?

The fundamental parts of software today, remains the same as LISA or NextStep software written 25 years ago, with a complete GUI metaphor, a true pre-emptive multitasking operating system, productivity applications an a true object oriented development environment.

Visual C++ 2005

Microsoft Visual C++ returns as mainstream programming language with the next release of Visual Studio. Microsoft enhances the runtime libraries, the STL and adds language constructs for .NET compatibility.

OO in One Sentence

Keep it DRY, Keep it Shy, and Tell the Other Guy..

Here is the original paper from Andy Hunt and Dave Thomas.

Operational - Reporting Databases

Martin Fowler's - Reporting Database

The separation of reporting database from the operational database provides unique advantages such as: data from business logic (calculated), a de-normalized view of database (fewer joins), maintainability of operational database and runtime performance (fewer locks)

See also:
* Martin Fowler Bliki
* Reporting from Database