Smart Digitizers

November 17, 2010July 5, 2021

Dealing with Time.. Be Careful!

Dealing with time is something crucial that we need to a pay very close attention to it. I like the aphorism that say " Time is like a river. You can’t touch the same water twice", This is very true statement and I am having it in front of me every single minute in my every day.

In my past days I wasted many days doing not useful things. I have a guilty feeling because of that and I hope if I can go back to fix that. But there is no Time-Machine that will get me back to that time to fix my mistakes. I hope if I can have a time-machine that will lead me to correct my mistakes I made in the past. I learned that in the hard way while I could learn it in the easy way if I listen to my father or teacher when they were telling me about an Arabic aphorism that says "Time life like a blade, if you did not kill it; it is going to kill you" meaning if you did not utilize your time in a very useful things, this will fire back on you after a while.

These days, I am trying to utilize every single minutes in my day and optimize my life for that. Well, I admit this is very hard but I would not make the same mistake as the old days. One thing that trigger me to write this article is a discussion I have with one of my family members about the impotency of time and how we should deal with it.He wanted to spend most of his time playing games and at coffee-shops. I was totally against this while he was trying to convenes me with his thought which I was totally disagree on them.

I believe you have to do funny things and spend time with family and friends but that does not means wasting the whole holiday days doing such a stuff. Playing Computer games , gambling , and spend the whole night with friends is not the best thing that you can do during holidays. For me, I need to balance between spending time with family/friends and reading and enhance my knowledge.

I would love to hear from you on this topic, Please share your thoughts on this topic by commenting on this article

November 13, 2010July 5, 2021

Outsourcing What and When?

Outsourcing becoming part of the core business of any successful business these days, one of the very nice articles I read couple of weeks ago was about outsourcing. It is explaining the outsourcing in a very good way and explain what to Outsource and when to do that. The subject of this article was "Outsourcing: What and When?" I strongly recommend to have couple of minutes reading this site.

November 8, 2010July 5, 2021

Date different in SQL server Vs Oracle

While setting back in my chair today and thinking of the power that MS tools giving to us , I decided to do a very small compare of things I can do in SQL server and how can I do the same thing in Oracle.

I decided to do a very primitive operation on both DBs… something is very silly. Just to get the differences between 2 dates in Weeks. This is very easy thing

In SQL Server I could do that in single line of SQL Statement

SELECT DATEDIFF (ww, ’03/20/1983′, ’11/03/2010′) DiffInWeeks_SQLServer

While I could do the same operation in Oracle by a long equation comparing with the one I have for SQL Serer:

SELECT (to_date(’03/20/1983′,’mm/dd/yyyy’) – to_date(’11/03/2010′,’mm/dd/yyyy’)

) / 7.0) DiffInWeeks_Oracle

FROM DUAL;

I still like working on Microsoft platforms.

November 8, 2010July 5, 2021

How Can I Enhance the Performance of .Net Application?

The performance of any system is considered as a key part of the requirements that client usually ask for implicitly. The poor perform application is most likely going to be failed because of that even if it is doing lot of very cool functionalities.
Recently I read an interesting article about this topic published on CodeGuru. They highlighted couple of key actions that is easy to be implemented and they are almost effortless but at the end those actions will improve the overall performance of you application by better utilization of server CPUs.
They depending on the fact that the CPUs we have these days is much sophisticated that previous days and we need to take benefits of that. I strongly recommend reading this article

September 28, 2010July 5, 2021

How to create OOP representations of XML

If you have an XML file and you are seeking for the best way to deal with it inside your code. You do not want to use XPath Queries intensively in your code and want to have the best way to deal with that XML… I faced such a case where I need to build a special configuration file for an FTP windows service. The way I wanted to build this XML file was in a hierarchy way something looks like the following XML:

<Ftp>

<RemoteHost>IP or the DNS name for the remote FTP server</RemoteHost>

<Username>FTP USerName</Username>

<Password>password</Password>

</Ftp>

<ScretPhase>Sec Phrase Goes here</ScretPhase>

</Security>

</FtpConnection>

This FTP service suppose to work with more than on FTPConnection. Thus the above configuration snap might occur more than one time. Which make it is harder to deal with .

The best way to deal with this configuration inside code is to create a object oriented representation of it and load this XML into it. then let your code deal with the OOP classes instead of directly with XML.

Well, there is a very easy way to build a OOP presentation of this XML. There is a tool that is shipped with .Net framework & visual studio called XSD. You can use this tool to generate the OOP representation by first create XSD schema for your XML then convert that schema to OOP presentations. Below is how to do that step by step.

I created a file on my desktop and I called it "FTPConfig.xml", I paste the following XML into it.

<Root>

<Ftp>

<RemoteHost>IP or the DNS name for the remote FTP server</RemoteHost>

<Username>FTP USerName</Username>

<Password>password</Password>

</Ftp>

<ScretPhase>Sec Phrase Goes here</ScretPhase>

</Security>

</FtpConnection>

<Ftp>

<RemoteHost>IP or the DNS name for the remote FTP server</RemoteHost>

<Username>FTP USerName</Username>

<Password>password</Password>

</Ftp>

<ScretPhase>Sec Phrase Goes here</ScretPhase>

</Security>

</FtpConnection>

</Root>

· Note that I duplicated the FTPConnection tag twice, I did that for a purpose. I did that to tell XSD tool to expect this tag to occur more than once. Thus when XSD tool build the Schema representation of it, it will make the MAX occurrence of this tag as infinite

2. From Start menu, open "Visual Studio 2008 Command Prompt"… it is Command prompt but has special configurations to open some Command Prompt tools shipped with VS 2008

3. We need to set the current folder on CMD to be the desktop. To do so, write the following comand

Cd c:\users\[windowsUserName]\desktop

· Where [WindowsUserName] is the login name that you are using to login into your PC

4. Now we need to create the XSD schema file for this XML. To do that, write the following command into your CMD

xsd FTPConfig.xml

· The output from this command is an XSD file and it will placed on your Desktop; the name of this XSD file suppose to be FTPConfig.xsd; My advice to you is to take couple of minutes to review this Schema file and make sure it is meeting your expectation.

5. Now we need to Create the OOP presentation of this XSD; to do so, write the following command

xsd FTPConfig.xsd /classes /language:CS

a. The meaning of parameter /Classes : will make the output of this command to be Classes not DataSet.

b. While the Meaning of parameter /language is the programming language in which the code will be generated; CS means C# language

The output form this command suppose a C# code placed on your desktop.

My recommendation to you is to keep all the generated classes into a single class and do not split each class into a separated file. I am saying this because you might decide to change the configuration a little bit and you need to regenerate those classes again. So if you split those classes into different files, then you will get into a loop of re-splitting the classes again and again.

I hope you will find this topic helpful. Please feel free to send any comments/questions.

September 27, 2010July 5, 2021

What is Unit testing and what benefits I will have if I apply it on my project

What is Unit Test:

In computer programming, unit testing is a software design and development method where the programmer verifies that individual units of source code are working properly. A unit is the smallest testable part of an application.

In OOP, the smallest unit is a method, which may belong to a base/super class, abstract class or derived/child class.

Unit testing is typically done by software developers to ensure that the code other developers have written meets software requirements and behaves as the developer intended.

Benefits of Applying Unit Test:

Using developer time for manual ad hoc testing is not a cost effective way of ensuring software quality. (Code coverage, breaking code by others, did I test all functionalities)
Human tester can and will make mistakes.. Even if Company have QA, discovering issues at QA side is more expensive than @ DEV side.
unit tests find problems early in the development cycle.
an automated unit test suite watches over your code in two dimensions: time and space
developers will be less afraid to change existing code
the development process becomes more flexible (Sending hotfixes more quickly)
Improves your project’s truck factor:

Truck factor is the minimum number of developers that if hit by a truck the project would grind to a halt. If you have one key developer who works on a subsystem that no-one else knows, then your truck factor is effectively “1”. Obviously, having truck factor of “1” is a risk on the project.

A comprehensive unit test suite improves truck factor because it makes it easier for a developer to take over a piece of code she is not intimately familiar with. A developer can start working on code written by others because the unit tests will guide the developer by pointing it out if she makes an error. Losing a key developer for any reason just before a release is less of a catastrophe if you have the safety net of unit tests.

reduces the need for manual testing

Flavors of Unit testing:

Point unit tests exercise a small piece of functionality, e.g., just one method or methods of a class.
End-to-End tests exercise one feature across many, sometimes all, layers of an application; An ideal end-to-end test works like an end user story

Test Driven Programming model: Developer start developing test methods and basic functions that make test methods success, then enhance code at methods to make sure it will cover all expected/unexpected cases.

As a rule, before a developer checks in any code into the main source control repository, she should get the latest versions of the unit tests from the version control on her development machine and run all the tests locally. Only after all unit tests pass should the developer check in new code. This ensures that the source code in the version control system remains healthy at all times and can be used to rebuild the system at any time.

In real life, developers may accidentally check in code that does not work. The daily build should be your main line of defense against these bugs.

Real Word Facts:

Trusting unit tests blindly as in: "if unit tests pass, code is ready for production" is a recipe for shipping bugs. Even if we have a comprehensive unit test suite that is run frequently, bugs can still sneak in and some amount of manual testing by humans is needed.

What if Bug appear on Production:

We need to do "post mortem" analysis.. One of the following things turned out:

We have 2 bugs: one inside actual Code and the other inside Unit test code.
There is no unit test code that testing this functionality.
Production environment is different from Test environment.

Finally, If you have plenty of time at your project to apply Unit testing on it, the I would strongly recommend applying it.

September 25, 2010July 5, 2021

State Design Pattern

Introduction:
Sometimes you want to build a class where its behavior changed according to its state. State Design pattern provides a good class structure to solve this issue. State Design pattern also known as Object for state pattern is used to represent the state of an object and the object behavior will changed according to state changes.
Example:

static void Main(string[] args)
{
WaterCompound c = new WaterCompound(0);
c.IncreaseTempreture(10);
c.IncreaseTempreture(100);
c.DecreaseTempreture(99);
c.DecreaseTempreture(40);
c.DecreaseTempreture(50);
Console.ReadKey();
}
class WaterCompound : Compound
{
public WaterCompound(int temp)
{
_state = new LiquiedState(this,temp,0,100);
}
}
public class Compound
{
public State _state;
public void IncreaseTempreture(int temp)
{
_state.IncreaseTempreture(temp);
Console.WriteLine(” Balance = {0:D}”, _state.Tempreture);
Console.WriteLine(” Status = {0}\n”,
this._state.GetType().Name);
Console.WriteLine(“—————-“);
}
public void DecreaseTempreture(int temp)
{
_state.DecreasseTempreture(temp);
Console.WriteLine(” Balance = {0:D}”, _state.Tempreture);
Console.WriteLine(” Status = {0}\n”,
this._state.GetType().Name);
Console.WriteLine(“—————-“);
}
}
public abstract class State
{
protected Compound _compound;
public int LowerTempLimit { get; set; }
public int UpperTempLimit { get; set; }
public int Tempreture { get; set; }
public abstract void IncreaseTempreture(int temp);
public abstract void DecreasseTempreture(int temp);
}
class BoilingState:State
{
public BoilingState(Compound c,int temp,int lowerTemp,int Uppertemp)
{
Tempreture = temp;
base._compound = c;
LowerTempLimit = lowerTemp;
UpperTempLimit = Uppertemp;
}
public override void IncreaseTempreture(int temp)
{
Tempreture += temp;
}
public override void DecreasseTempreture(int temp)
{
Tempreture -= temp;
if (Tempreture < LowerTempLimit)
base._compound._state = new LiquiedState(_compound, Tempreture,0,100);
}
}
class FreezingState:State
{
public FreezingState(Compound c,int temp,int lowerTemp,int Uppertemp)
{
Tempreture = temp;
base._compound = c;
LowerTempLimit = lowerTemp;
UpperTempLimit = Uppertemp;
}
public override void IncreaseTempreture(int temp)
{
Tempreture += temp;
if (Tempreture > UpperTempLimit)
_compound._state = new LiquiedState(_compound, Tempreture,0,100);
}
public override void DecreasseTempreture(int temp)
{
Tempreture -= temp;
}
}
class LiquiedState:State
{
public LiquiedState(Compound c,int temp,int lowerTemp,int Uppertemp)
{
Tempreture = temp;
base._compound = c;
LowerTempLimit = lowerTemp;
UpperTempLimit = Uppertemp;
}
public override void IncreaseTempreture(int temp)
{
Tempreture += temp;
if (Tempreture > UpperTempLimit)
_compound._state = new BoilingState(_compound, Tempreture,101,100000);
}
public override void DecreasseTempreture(int temp)
{
Tempreture -= temp;
if (Tempreture < LowerTempLimit)
_compound._stae = new FreezingState(_compound, Tempreture,-150,-1);
}
}

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September 21, 2010July 5, 2021

Command Design Pattern

Introduction:
Command Design Pattern enables you to encapsulate a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations.
Example:
The below code demonstrates the Command pattern to be used on a simple calculator. This caluclator doing unlimited number of undo’s & Redo’s .

One thing we might do to extend this Calculator project, is to create an IOperator Interface and for each operation have a concret Operator Class. for simplicity I am not going to do this. I will hard code couple of operator to make it very simple to be understood.

static void Main()
{
// Create user and let her compute
User user = new User();
// User presses calculator buttons
user.Calculate(‘+’, 100);
user.Calculate(‘-‘, 50);
user.Calculate(‘*’, 10);
user.Calculate(‘/’, 2);
// Undo 4 commands
user.UndoCalculation(4);
// Redo 3 commands
user.RedoCalculation(3);
// Wait for user
Console.ReadKey();
}
interface ICommand
{
void Execute();
void UnExecute();
}
class CalculationCommand : ICommand
{
private char _operator;
private int _operand;
private Calculator _calculator;
// Constructor
public CalculationCommand(Calculator calculator,
char @operator, int operand)
{
this._calculator = calculator;
this._operator = @operator;
this._operand = operand;
}
// Gets operator
public char Operator
{
set { _operator = value; }
}
// Get operand
public int Operand
{
set { _operand = value; }
}
// Execute new command
public void Execute()
{
_calculator.Operation(_operator, _operand);
}
// Unexecute last command
public void UnExecute()
{
_calculator.Operation(Undo(_operator), _operand);
}
// Returns opposite operator for given operator
private char Undo(char @operator)
{
switch (@operator)
{
case ‘+’: return ‘-‘;
case ‘-‘: return ‘+’;
case ‘*’: return ‘/’;
case ‘/’: return ‘*’;
default: throw new
ArgumentException(“@operator”);
}
}
}
class Calculator
{
private int _currentIndex = 0;
public void Operation(char @operator, int operand)
{
switch (@operator)
{
case ‘+’: _currentIndex += operand; break;
case ‘-‘: _currentIndex -= operand; break;
case ‘*’: _currentIndex *= operand; break;
case ‘/’: _currentIndex /= operand; break;
}
Console.WriteLine(
“Current value = {0,3} (following {1} {2})”,
_currentIndex, @operator, operand);
}
}
class User
{
// Initializers
private Calculator _calculator = new Calculator();
private List<ICommand> _commands = new List<ICommand>();
private int _currentIndex = 0;
public void RedoCalculation(int levels)
{
Console.WriteLine(“\n—- Redo {0} levels “, levels);
// Perform redo operations
for (int i = 0; i < levels; i++)
{
if (_currentIndex < _commands.Count – 1)
{
ICommand command = _commands[_currentIndex++];
command.Execute();
}
}
}
public void UndoCalculation(int levels)
{
Console.WriteLine(“\n—- Undo {0} levels “, levels);
// Perform undo operations
for (int i = 0; i < levels; i++)
{
if (_currentIndex > 0)
{
ICommand command = _commands[–_currentIndex] as ICommand;
command.UnExecute();
}
}
}
public void Calculate(char @operator, int operand)
{
// Create command operation and execute it
ICommand command = new CalculationCommand(
_calculator, @operator, operand);
command.Execute();
// Add command to undo list
_commands.Add(command);
_currentIndex++;
}
}

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September 20, 2010July 5, 2021

Iterator Design Pattern

Introduction:
Sometimes you want to access a collection of objects in a sequential way without even expose how things is going inside your implementation . Iterator Design Pattern Provides you with a Skelton of how to design your classes to solve this issue.
Example:

static void Main(string[] args)
{
ListAggregate a = new ListAggregate();
a[0] = “Item A”;
a[1] = “Item B”;
a[2] = “Item C”;
a[3] = “Item D”;
// Create Iterator and provide aggregate
ListIterator i = new ListIterator(a);
Console.WriteLine(“Iterating over collection:”);
string item = i.FirstItem();
while (item != null)
{
Console.WriteLine(item);
item = i.NextItem();
}
// Wait for user
Console.ReadKey();
}
class ListIterator : Iterator
{
private ListAggregate _aggregate;
private int _current = 0;
// Constructor
public ListIterator(ListAggregate aggregate)
{
this._aggregate = aggregate;
}
// Gets first iteration item
public override string FirstItem()
{
return (string)_aggregate[0];
}
// Gets next iteration item
public override string NextItem()
{
string ret = null;
if (_current < _aggregate.Count – 1)
{
ret = (string)_aggregate[++_current];
}
return ret;
}
// Gets current iteration item
public override string CurrentItem()
{
return (string)_aggregate[_current];
}
// Gets whether iterations are complete
public override bool HasMoreItems()
{
return _current >= _aggregate.Count;
}
}
class ListAggregate : Aggregate
{
private ArrayList _items = new ArrayList();
public override Iterator CreateIterator()
{
return new ListIterator(this);
}
// Gets item count
public int Count
{
get { return _items.Count; }
}
// Indexer
public string this[int index]
{
get { return (string)_items[index]; }
set { _items.Insert(index, value); }
}
}
abstract class Iterator
{
public abstract string FirstItem();
public abstract string NextItem();
public abstract bool HasMoreItems();
public abstract string CurrentItem();
}
abstract class Aggregate
{
public abstract Iterator CreateIterator();
}

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September 19, 2010July 5, 2021

Mediator Design Pattern

Introduction:
Sometimes you want to design your classes set that interact with each other in a loosely coupled manner by keeping your classes away from referring each other directly… Mediator Design Pattern solve this issue by promoting the idea of loosely coupling classes

Example:

static void Main(string[] args)
{
CountryList countrylist = new CountryList();

CityList city = new CityList();
PhoneNumberTextBox phone = new PhoneNumberTextBox();

countrylist.RegisterMonitorChangers(city);
countrylist.RegisterMonitorChangers(phone);

Console.WriteLine(“——————-“);
countrylist.SelectCountry(“USA”);
Console.WriteLine(“——————-“);
countrylist.SelectCountry(“Jordan”);

Console.ReadKey();

}

abstract class CountryListChangesMonitorBase
{
public CountryList TriggerList { get; set; }

public abstract void RecieveChange(string countryName);
}

class CountryList
{
List<string> countries = new List<string>();
string selectedCountry = “”;

List<CountryListChangesMonitorBase> participants = new List<CountryListChangesMonitorBase>();

public CountryList()
{
countries.Add(“USA”);
countries.Add(“UK”);
countries.Add(“Jordan”);
countries.Add(“Jaban”);
countries.Add(“Germani”);

}

public void SelectCountry(string countryName)
{
if (countries.Contains(countryName))
selectedCountry = countryName;

foreach (CountryListChangesMonitorBase p in participants)
p.RecieveChange(countryName);
}

public void RegisterMonitorChangers( CountryListChangesMonitorBase monitor)
{
if (!participants.Contains(monitor))
participants.Add(monitor);

monitor.TriggerList = this;
}

}

class CityList:CountryListChangesMonitorBase
{
public override void RecieveChange(string countryName)
{
Console.WriteLine(” Display available City List for : ” + countryName);
}
}

class PhoneNumberTextBox: CountryListChangesMonitorBase
{
public override void RecieveChange(string countryName)
{
Console.WriteLine(” Display phone number code for : ” + countryName);
}
}

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