which OOP Pattern to use

[Dormilich]

I’m not that good with OOP Patterns, so I better ask before I code in the wrong direction.

the scenario is quite simple, I have a DB table which holds different types of text (designated by a type field), based on that type I need a class (I usually fetch the DB result in a class) to use different output templates.

I’m pretty sure there is a Pattern for exactly that purpose, just which one? Strategy, State, Template or something other?

PS. a good reference is always appreciated.

[Markus]

Sounds like a simple factory would do. You delegate object creation to the factory, that is, you let the factory decide, on whatever criteria, which object to return.

class TextTypeFactory {
    public static function create($text_type) {
        switch ($text_type) {
            case 'varchar': return new VarChar; break;
            // etc ...
        }
    }
}

[Dormilich]

does this look like a sensible implementation?

<?php
interface iText
{
	public function getData();
	public function getID();
}

class NoText implements iText
{
	protected $id;

	public function __construct($id)
	{
		$this->id = $id;
	}

	public function getID()
	{
		return $this->id;
	}

	public function getData()
	{
		return "";
	}
}
// if I remember right, constructors are inherited
class BlockText extends NoText
{
	public $display = "Display5";
	
	public function getData()
	{
		$dbh = new DBH("-- some SQL");
		return $dbh->execute($this->id)
				   ->fetch(DBH::FETCH_CLASS, $this->display);
	}
}

class RoleText extends NoText
{
	public $display = "Display1";
	
	public function getData()
	{
		$dbh = new DBH("-- some other SQL");
		return $dbh->execute($this->id)
				   ->fetch(DBH::FETCH_CLASS, $this->display);
	}
}

abstract class aTextFactory
{
	abstract public static function createTextObj($id)
}

class TextObj extends aTextFactory
{
	public static function createTextObj($id)
	{
		$type = (int) self::getTextType($id);
		switch ($type) {
			case 1: 
				$db_obj = new RoleText($id); break;
			case 5: 
				$db_obj = new BlockText($id); break;
			default:
				$db_obj = new NoText($id);
		}
		return $db_obj;
	}
	
	private static function getTextType($id)
	{
		$dbh = new DBH("SELECT `type` FROM entry WHERE `ID` = ? ");
		return $dbh->execute($id)
		           ->fetch(DBH::FETCH_ONE);
	}
}

class TextChunk
{
	private $text_obj = NULL;
	
	public function __construct($id)
	{
		$this->text_obj = TextObj::createTextObj($id);
	}
	
	public function __toString()
	{
		return $this->text_obj->getData();
	}
	
	public function getID()
	{
		return $this->text_obj->getID();
	}
}
?>

[Markus]

Looks fine to me :)

[Dormilich]

I’ll do thorough testing not before weekend, I guess. still I’m excited.