php example
<?php
/**
* The smallest cohesive interface we can think of for this type
* of Decorator. This is the Component interface.
*/
interface HtmlElement
{ /** * @return string html code
*/
public function __toString();
/**
* @return string the name of the POST request key for this element,
* aka the "name" attribute.
*/
public function getName();
}
/**
* Represents a <input type="text" /> html element.
* It can be created programmatically and then printed.
* This is the only ConcreteComponent.
*/
class InputText implements HtmlElement
{
protected $_name;
public function __construct($name)
{
$this->_name = $name;
}
public function getName()
{
return $this->_name;
}
public function __toString()
{
return "<input type=\"text\" id=\"{$this->_name}\" name=\"{$this->_name}\" />\n";
}
}
/**
* Very simple base class to share the wrapping code between Decorators.
* This is the Decorator participant.
*/
abstract class HtmlDecorator implements HtmlElement
{
protected $_element;
public function __construct(HtmlElement $input)
{
$this->_element = $input;
}
/**
* All operations are delegated by default, not changing anything
* of the original behavior.
* ConcreteDecorators will override the methods they are interested in.
*/
public function getName()
{
return $this->_element->getName();
}
public function __toString()
{
return $this->_element->__toString();
}
}
/**
* Adds a custom <label> element alongside the <input> one.
* Example of ConcreteDecorator.
*/
class LabelDecorator extends HtmlDecorator
{
protected $_label;
public function setLabel($label)
{
$this->_label = $label;
}
public function __toString()
{
$name = $this->getName();
return "<label for=\"{$name}\">{$this->_label}</label>\n"
. $this->_element->__toString();
}
}
/**
* Adds a <span> containing an error message after the <input> element.
* Example of ConcreteDecorator.
*/
class ErrorDecorator extends HtmlDecorator
{
protected $_error;
public function setError($message)
{
$this->_error = $message;
}
public function __toString()
{
return $this->_element->__toString()
. "<span>{$this->_error}</span>\n";
}
}
$input = new InputText('nickname');
$labelled = new LabelDecorator($input);
$labelled->setLabel('Nick:');
echo "Using labelDecorator => \n",$labelled, "\n";
$input = new InputText('nickname');
$error = new ErrorDecorator($input);
$error->setError('You must enter a unique nickname');
echo "Using errorDecorator => \n",$error, "\n";
// how can we obtain a LabelledErrorInputText, which has both the <label>
// and <span> elements?
$input = new InputText('nickname');
$labelled = new LabelDecorator($input);
$labelled->setLabel('Nick:');
$error = new ErrorDecorator($labelled); // a Decorator wrapping another one
$error->setError('You must enter a unique nickname');
echo "Using both labelDecorator & errorDecorator => \n".$error;
?>
Output :
Using labelDecorator =>
<label for="nickname">Nick:</label>
<input type="text" id="nickname" name="nickname" />
Using errorDecorator =>
<input type="text" id="nickname" name="nickname" />
<span>You must enter a unique nickname</span>
Using both labelDecorator & errorDecorator =>
<label for="nickname">Nick:</label>
<input type="text" id="nickname" name="nickname" />
<span<You must enter a unique nickname>/span>
Some code in java
interface iComponent
{
public void doStuff();
}
class component implements iComponent
{
public void doStuff()
{
System.out.println("component does stuff");
}
}
interface decorator extends iComponent
{
public void addedBehaviour();
}
class concreteDecorator implements decorator
{
iComponent comp;
public concreteDecorator(iComponent comp)
{
super();
this.comp = comp;
}
public void addedBehaviour()
{
System.out.println("Added behaviour in decorator");
}
public void doStuff()
{
comp.doStuff();
addedBehaviour();
}
}
class concreteDeco2 implements decorator
{
iComponent comp;
public concreteDeco2(iComponent comp)
{
super();
this.comp = comp;
}
public void addedBehaviour()
{
System.out.println("Added behaviour in deco no 2");
}
public void doStuff()
{
comp.doStuff();
addedBehaviour();
}
}
public class decoClient
{
public static void main(String[] args)
{
iComponent comp = new component();
decorator deco = new concreteDecorator(comp);
deco.doStuff();
decorator deco2 = new concreteDeco2(comp);
deco2.doStuff();
}
}
Output :
component does stuff
Added behaviour in decorator
component does stuff
Added behaviour in deco no 2
