The Evolution of a Software Engineer

前言

转载：The Evolution of a Software Engineer 原文作者：Sean Hickey

---

The first year

class HelloWorld
{
	public static void main(String args[])
	{
		// Displays "Hello World!" on the console.
		System.out.println("Hello World!");
	}
}

The second year

/**
 * Hello world class
 *
 * Used to display the phrase "Hello World" in a console.
 *
 * @author Sean
 */
class HelloWorld
{
	/**
	 * The phrase to display in the console
	 */
	public static final string PHRASE = "Hello World!";
	
	/**
	 * Main method
	 *
	 * @param args Command line arguments
	 * @return void
	 */
	public static void main(String args[])
	{
		// Display our phrase in the console.
		System.out.println(PHRASE);
	}
}

The third year

/**
 * Hello world class
 *
 * Used to display the phrase "Hello World" in a console.
 *
 * @author Sean
 * @license LGPL
 * @version 1.2
 * @see System.out.println
 * @see README
 * @todo Create factory methods
 * @link https://github.com/sean/helloworld
 */
class HelloWorld
{
	/**
	 * The default phrase to display in the console
	 */
	public static final string PHRASE = "Hello World!";
	
	/**
	 * The phrase to display in the console
	 */
	private string hello_world = null;
	
	/**
	 * Constructor
	 *
	 * @param hw The phrase to display in the console
	 */
	public HelloWorld(string hw)
	{
		hello_world = hw;
	}
	
	/**
	 * Display the phrase "Hello World!" in a console
	 *
	 * @return void
	 */
	public void sayPhrase()
	{
		// Display our phrase in the console.
		System.out.println(hello_world);
	}
	
	/**
	 * Main method
	 *
	 * @param args Command line arguments
	 * @return void
	 */
	public static void main(String args[])
	{
		HelloWorld hw = new HelloWorld(PHRASE);
		try {
			hw.sayPhrase();
		} catch (Exception e) {
			// Do nothing!
		}
	}
}

The fifth year

/**
 * Enterprise Hello World class v2.2
 *
 * Provides an enterprise ready, scalable buisness solution
 * for display the phrase "Hello World!" in a console.
 *
 * IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED
 * TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER
 * PARTY WHO MAY MODIFY AND/OR REDISTRIVUTE THE LIBRARY AS
 * PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING
 * ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL
 * DAMAGES ATRISING OUT OF THE USE OR INABILITY TO USE THE
 * LIBRAY (INCLUDING BUT LIMITED TO LOSS OF DATA OR
 * DATA BEINT RENDERED INACCURATE OR LOSSES SUSTAINED BY
 * YOU OR THIRD PARTIES OR A FAILURE OF THE LIBRARY TO
 * OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER
 * OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGES.
 *
 * @author Sean
 * @license LGPL
 * @version 2.2
 * @see System.out.println
 * @see README
 * @see license.txt
 * @todo Test of OS compatibility
 * @link https://github.com/sean-inc/helloworld
 */
class HelloWorld
{
	/**
	 * The first phrase
	 */
	public static final string PHRASE_HELLO = "Hello";
	
	/**
	 * The second phrase
	 */
	public static final string PHRASE_WORLD = "World";
	
	/**
	 * The first word in our phrase
	 */
	private Word hello = null;
	
	/**
	 * The second word in our phrase
	 */
	private Word world = null;
	
	/**
	 * Constructor
	 *
	 * @param hello First word to display in the console
	 * @param world Second word to display in the console
	 */
	public HelloWorld(Word hello, Word world)
	{
		this.hello = hello;
		this.world = world;
	}
	
	/**
	 * Display the phrase "Hello World!" in a console
	 *
	 * @return void
	 */
	public void sayPhrase()
	{
		// Display our phrase in the console.
		string first  = this.hello.toString();
		string second = this.world.toString();
		System.out.println(first + " " + second + "!");
	}
	
	/**
	 * Sets the phrase to use for hello
	 *
	 * @param h The first phrase
	 * @return void
	 */
	public void setHello(string h)
	{
		this.hello.setWord(h);
	}
	
	/**
	 * Gets the phrase to use for hello
	 *
	 * @return Word
	 */
	public Word getHello()
	{
		return this.hello;
	}
	
	/**
	 * Sets the phrase to use for world
	 *
	 * @param w The second phrase
	 * @return void
	 */
	public void setWorld(string w)
	{
		this.world.setWord(w);
	}
	
	/**
	 * Gets the phrase to use for world
	 *
	 * @return Word
	 */
	public Word getHello()
	{
		return this.world;
	}
	
	/**
	 * Main method
	 *
	 * @param args Command line arguments
	 * @return void
	 */
	public static void main(String args[])
	{
		// Create a new dic so we can display our phrase on the
		// command line.
		DIC d = DependencyInjectionContainer::factory();
		HelloWorld hw = null;
		
		try {
			hw = d.newInstance(HelloWorld.class);
		} catch (DICInstanceException e) {
			System.err.println("There was an error creating an instance of HelloWorld.");
			return;
		}
		
		try {
			hw.setHello(PHRASE_HELLO);
			hw.setWorld(PHRASE_WORLD);
			hw.sayPhrase();
		} catch (IOException e) {
			System.err.println("There was an IO error.");
		} catch (ConsoleException e) {
			System.err.println("There was a console error.");
		} catch (Exception e) {
			System.err.println("There was an unknown error.");
		}
	}
}

<beans xmlns="http://www.framework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.framework.org/schema/beans
	http://www.framework.org/schema/beans/beans-2.5.xsd
	http://www.framework.org/schema/context
	http://www.framework.org/schema/context/context-2.5.xsd">
	<context:annotation-config />
	<bean id="HelloWorldBean" class="com.sean-inc">
		<property name="hello" value="Word" />
		<property name="world" value="Word" />
	</bean>
</beans>

The tenth year

/**
 * Used to display the phrase "Hello World!" in a console
 *
 * @author Sean
 * @see README
 */
class HelloWorld
{
	public static void main(String args[])
	{
		System.out.println("Hello World!");
	}
}

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后记

代码中显示的Github地址：https://github.com/sean/