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7 habits of highly effective freelance programmers

admin — Mon, 18 Feb 2008 17:45:23 +0000

I have developed these based on my freelancing experience. Though I have discontinued freelancing, but would like to share my practices with you. These are basic practices and have been developed over time with experience (good and bad). Please feel free to leave your experiences and comment on this article.

1. Communicate with your clients frequently

This I believe is the most important habit that you should inculcate. Keeping the client in the loop ensures them that you are on top of things and that you are working on their project. Think about it! what if you were the client and were paying someone to develop something. Wouldn’t you want to hear from your vendor frequently?

Issues, slippages, project statuses should be frequently updated to the client (irrespective if your client asks or not). Itâ€™s professional ethics!

2. Document interactions with your client

Following point 1, you will have a lot of interactions with your client. You should record/document these interactions as a habit. These interactions could either be in the form of a chat message, emails or function specification documents. Maintaining a history of such interactions will help you during the closure of the project and mainly towards User Acceptance Testing (UAT).

3. Maintain on-going relations with all parties

Just because a project is over does not mean that you should not maintain relations with your clients. Greeting your client on birthdays, anniversaries, etc makes them feel good. This exercise is good to build rapport with clients. It always keeps you fresh in their minds. So, the next time they have a project; guess who gets called first.

In addition to above, you should also maintain relations with suppliers or other freelancers who you outsource work to. In the long run it helps build trust and gives you a good bargaining power. Think about it.

4. Get yourself a professional identity

So what if you freelance, it doesn’t mean that you should not carry yourself professionally. Create professional looking logos, business cards, stationery and website (very important).

Get a professional copy writer to help you with the content of your website. You should mention the projects that you have done and the skills that you have. Always have a contact form on your website where prospective clients can contact you (and when you do get contacted, reply immediately).

5. Seek testimonials from your clients

Seek testimonials from your clients after closing a project. Get this on email and catalogue it for future reference. Also seek their permission to publish their testimonials on your website. In addition to this, you should consider requesting permission from your clients if its ok to give their contact information for reference checks. Some prospective clients would like to talk to your old clients and gauge the experience they have had with you.

6. Create reusable libraries

Creating reusable libraries makes you more profitable. Think about it! If you have been creating email validators on forms for nearly all projects, it makes more sense to create a reusable library and import that library in your current project and make use of it. This way your effort on the project in the long run is reduced and hence you get paid for something that has already been done.

In addition to this, if you discover a bug and fix it, you can apply a patch immediately to all your projects. Saves your time there too and helps all your clients with the bug fix in one go.

7. Maintain proper accounts

Many freelancers (including me) have failed at this. We fail at this not because we don’t know how to handle finances or accounts, but because we are programmers… we love to write code… not books. Do you agree with me?.

But the hard reality is that at the end of the financial year we need to pay taxes. To pay taxes properly we need a good accounting system. The choice is up to you, either be disciplined and maintain proper accounts from day one or waste a lot of time towards the end of the financial year doing it.

I recommend that you do it as you go along. I recommend that you dedicate a weekend to file your papers/accounts properly.

Please feel free to post your comments or add to this list your experiences and best practices.

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PHP 5 Tutorial – Handling Exceptions in PHP5

admin — Thu, 14 Feb 2008 08:58:21 +0000

In this tutorial we will cover the following:

What is an exception?
The use of a try…catch block
Anatomy of PHP5 Exception class
Extending the Exception class
A note on unhanded exceptions

What is an exception?

An exception is a logical/system error that occurs during the normal execution of a script. The exception could either be raised by the system or the program itself it the exception cannot be handled and the caller script/function needs to be informed about the same.

The use of a try…catch block

PHP5 introduces the try…catch block to trap exceptions. Look at the example below.

 
try {
   check();
}
catch(Exception $e) {
   echo "Message : " . $e->getMessage();
   echo "Code : " . $e->getCode();
}
 
function check() {
   if(some error condition) {
      throw new Exception("Error String",Error Code);
   }
}

In the above example, the method check() is called between the try {} block. The try{} block is the area where you will place your code that could raise an exception. Below the try{} block is the catch() {} block. The catch block expects the Exception type of object as a parameter. Within the catch() {} block you will place your logic to either fix the issue or log the error.

In the function check(), we raise an Exception using the ‘throw’ keyword. The statement following ‘throw’ is the syntax of creating a new object of Exception type. The exception class accepts two parameters. The left parameter is a string that is the error message and the right parameter is the integer error code that you wish to assign to that error.

Anatomy of PHP5 Exception class

 
class Exception {
	protected $message;
	protected $code;
	protected $file;
	protected $line;
 
	private $string;
	private $trace;
 
	public function __construct($message = null, $code = 0);
	public function __toString();
 
	final public function getCode();
	final public function getMessage();
	final public function getFile();
	final public function getLine();
	final public function getTrace();
	final public function getTraceAsString();
	final private __clone();
}

In the above example, except for __construct and __toString(), no other method can be overridden as all other methods are ‘final’.

Related Reading:

PHP5 Tutorial – Creating a PHP5 Constructor __construct()

PHP5 Tutorial – Defining Attributes of a PHP5 Class

PHP5 Tutorial OOPS – PHP5 Class Access Specifiers – public, private and protected

PHP 5 Tutorial – Final Class and Methods

PHP5 Tutorial – Magic Methods – __toString() method

Extending the Exception class

You can also extend the exception class as follows:

 
class CustomerException extends Exception {
 
  public function __construct($message = null, $code = 0) {
 
    $t_message = "Exception raised in CustomerException ";
    $t_message .= "with message : " . $message;
 
    parent::__construct($t_message, $code);
 
    }
 
}
 
 
function testException() {
 
	throw new CustomerException("CustomerException has been raised",101);
 
}
 
try {
	testException();
}
catch(CustomerException $e) {
	echo "Error Message : " $e->getMessage();
	echo "Error Code : " $e->getCode();
}

Output:

Error Message : CustomerException has been raised
Error Code : 101

Related Reading:
PHP5 Tutorial – Inheritance

A note on unhanded exceptions

All un-handled exceptions are passed up the function stack order till the time either a try…catch block is not made available. If a try…catch block is unavailable it is passed to the PHP core and the program execution stops there.

Please feel free to write back for any clarification.

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PHP 5 Tutorial – Final Class and Methods

admin — Thu, 14 Feb 2008 06:41:17 +0000

In this PHP tutorial we will understand the following:

Meaning of Final Class
Meaning of Final Method
When to declare a class as final
When to declare a method as final

Meaning of Final Class

A final class is a class that cannot be extended. To declare a class as final, you need to prefix the ‘class’ keyword with ‘final’. Example below.

 
final class BaseClass {
   public function myMethod() {
      echo "BaseClass method called";
   }
}
 
//this will cause Compile error
class DerivedClass extends BaseClass {
   public function myMethod() {
      echo "DerivedClass method called";
   }
}
 
$c = new DerivedClass();
$c->myMethod();

In the above example, BaseClass is declared as final and hence cannot be extended (inherited). DerivedClass tries to extend from BaseClass and hence the compiler will throw a compile error.

Meaning of Final Method

A final method is a method that cannot be overridden. To declare a method as final, you need to prefix the function name with the ‘final’ keyword. Example below:

 
class BaseClass {
   final public function myMethod() {
      echo "BaseClass method called";
   }
}
 
class DerivedClass extends BaseClass {
   //this will cause Compile error
   public function myMethod() {
      echo "DerivedClass method called";
   }
}
 
$c = new DerivedClass();
$c->myMethod();

In the above example, DerivedClass extends from BaseClass. BaseClass has the method myMethod() declared as final and this cannot be overridden. In this case the compiler causes a compile error.

When to declare a class as final

You should declare a class as final when you think that you implementation of that class should not change in the derived class. You should do this mainly for Utility classes where you don’t want the behavior/implementation of your class to change.

When to declare a method as final

You should declare a class method as final when you think that the method you develop contains necessary functionality to support your application and any modification or change to the functionality can cause unexpected errors/bugs.

Please feel free to write back for any clarification.

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PHP 5 Tutorials – Static Data Members and Methods

admin — Tue, 12 Feb 2008 09:47:49 +0000

In this tutorial you will learn all about static data members and methods

Meaning of static data members
Meaning of static methods
Defining static data members in PHP5
Defining static methods in PHP5
Accessing static data members in PHP5
Accessing static methods in PHP5
Rules to keep in mind for static methods

Meaning of static data members

A data member that is commonly available to all objects of a class is called a static member. Unlike regular data members, static members share the memory space between all objects of the same class.

Meaning of static methods

A static method is a class method that can be called without creating an instance of a class. Such methods are useful when creating utility classes.

Defining static data members in PHP5

To define a static member in PHP5 you need to prefix the class member name with the keyword ‘static’. Look at the example below.

 
class Customer {
 
	private $first_name; // regular member
	static public $instance_count; //static data member
 
}

In the above example $instance_count is declared as a static data member

Defining static methods in PHP5

To define a static data methods in PHP5 you need to prefix the class method name with the keyword ‘static’. Look at the example below.

 
class Customer {
 
	public function getFirstName() {
		//body of method
	}
 
	static public function getInstanceCount() {
		//body of method
	}
}

In the above example getInstanceCount is declared as a static method

Accessing static data members in PHP5

A static member data can be accessed using the name of the class along with the scope resolution operator (::) i.e. you donâ€™t need to create an instance of that class

Look at the example below:

 
class Customer {
 
	static public $instance_count = 0; //static data member
 
	public function __construct() {
		Customer::$instance_count++;
	}
 
	public function __destruct() {
		Customer::$instance_count--;
	}
 
	public function getFirstName() {
		//body of method
	}
 
	static public function getInstanceCount() {
		//body of method
	}
}
 
$c1 = new Customer();
$c2 = new Customer();
 
echo Customer::$instance_count;

Output:
2

In the above example, $instance_count is a static data member. Every time a new object is created the constructor is executed and the $instance_count variable is incremented by one. To echo the value contained in $instance_count variable, we use the :: (scope resolution) operator.

Accessing static method in PHP5

A static method can be accessed using the name of the class along with the scope resolution operator (::) i.e. you donâ€™t need to create an instance of that class. However, you can also access it with an instance variable.

Look at the example below:

 
class Customer {
 
	static public $instance_count = 0; //static data member
 
	public function __construct() {
		Customer::$instance_count++;
	}
 
	public function __destruct() {
		Customer::$instance_count--;
	}
 
	public function getFirstName() {
		//body of method
	}
 
	static public function getInstanceCount() {
		return Customer::$instance_count;
	}
}
 
$c1 = new Customer();
$c2 = new Customer();
 
echo Customer::getInstanceCount(); //this is using the scope resolution operator
echo $c1->getInstanceCount(); //this is using the instance variable

Output:
2
2

Rules to keep in mind for static methods

A static method can only access static data members
A static method does not have access to the $this variable

Please feel free to write back for any clarification.

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PHP5 OOPS Tutorials – Polymorphism

admin — Mon, 11 Feb 2008 07:09:09 +0000

In this tutorial we will learn the following:

Meaning of Polymorphism
Why method polymorphism cannot be achieved in PHP
PHP 5 Object Polymorphism

Meaning of Polymorphism

Polymorphism is derived from two Greek words. Poly (meaning many) and morph (meaning forms). Polymorphism means many forms. In C you have two methods with the same name that have different function signatures and hence by passing the correct function signature you can invoke the correct method.

This is how polymorphism is achieved in languages like C where in a function sum(int, int) differs from sum(float, float). Therefore the method sum() has many forms depending on the parameters being passed to it.

The meaning with Object Oriented languages changes. With Object Oriented language polymorphism happens:

When the decision to invoke a function call is made by inspecting the object at runtime it is called Polymorphism

Why method polymorphism cannot be achieved

The reason why polymorphism for methods is not possible in PHP is because you can have a method that accepts two parameters and call it by passing three parameters. This is because PHP is not strict and contains methods like func_num_args() and func_get_arg() to find the number of arguments passed and get a particular parameter.

Because PHP is not type strict and allows variable arguments, this is why method polymorphism is not possible.

PHP 5 Polymorphism

Since PHP 5 introduces the concept of Type Hinting, polymorphism is possible with class methods. The basis of polymorphism is Inheritance and overridden methods.

Lets look at an example:

 
class BaseClass {
   public function myMethod() {
      echo "BaseClass method called";
   }
}
 
class DerivedClass extends BaseClass {
   public function myMethod() {
      echo "DerivedClass method called";
   }
}
 
function processClass(BaseClass $c) {
   $c->myMethod();
}
 
$c = new DerivedClass();
processClass($c);

In the above example, object $c of class DerievedClass is executed and passed to the processClass() method. The parameter accepted in processClass() is that of BassClass. Within the processClass() the method myMethod() is being called. Since the method is being called on the class variable of BaseClass, it would not be wrong to assume that myMethod() of class BaseClass will be called. But, as per the definition “When the decision to invoke a function call is made by inspecting the object at runtime it is called Polymorphism”, myMethod() will be called on object DerievedClass. The reason why this happens is because the object of DerievedClass is being passed and hence the method myMethod() of DerievedClass will be called.

Please feel free to write back for any clarification.

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Stack Implementation in PHP5 – Stack Class

admin — Tue, 13 Nov 2007 20:47:41 +0000

Refer to the code below which is a PHP5 Stack Class – an implementation of Stacks. You are free to use it in your programs.

class Stack {
 
	private $stk = array();
 
	public function __construct() {
	}
 
	public function push($data) {
		array_push($this->stk, $data);
	}
 
	public function pop() {
		return array_pop($this->stk);
	}
 
}
 
$s = new Stack();
 
$s->push("Sunil");
$s->push("Bhatia");
 
echo $s->pop();
echo "\n";
echo $s->pop();

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