Composite

Purpose:

To treat a group of objects the same way as a single instance of the object.

RenderableInterface.php

<?php 

namespace DesignPatterns\Structural\Composite;

interface RenderableInterface
{
    public function render(): string;
}
?>

　　

Form.php

<?php 

namespace DesignPatterns\Structural\Composite;

/**
 * The composite node MUST extend the component contract. This is mandatory for building
 * a tree of components.
 */
class Form implements RenderableInterface
{
    /**
        * Varibles Description
        *
        * @var RenderableInterface[]
    */
    private $elements;

    /**
     * runs through all elements and calls render() on them, then returns the complete representation
     * of the form.
     *
     * from the outside, one will not see this and the form will act like a single object instance
     *
     * @return string
     */
    public function render(): string
    {
        $formCode = '<form>';

        foreach ($this->elements as $element) {
            $formCode .= $element->render();
        }

        $formCode .= '</form>';

        return $formCode;
    }

    /**
        * @param RenderableInterface $element
        *
        * @return Void
    */
    public function addElement(RenderableInterface $element)
    {
        $this->elements[] = $element;
    }
}

?>

 

InputElement.php

<?php 

namespace DesignPatterns\Structural\Composite;

/**
 * Input Element
 */
class InputElement implements RenderableInterface
{
    /**
        * Function Description
        *
        * @return string
    */
    public function render(): string
    {
        return '<input type="text" />';
    }
}

?>

　　

TextElement.php

<?php 

namespace DesignPatterns\Structural\Composite;

/**
 * Text Element
 */
class TextElement implements RenderableInterface
{
    /**
        * Varibles Description
        *
        * @var String
    */
    private $text;

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

    /**
        * Render
        *
        * @return string $text
    */
    public function render(): string
    {
        return $this->text;
    }
}
?>

　　

　

Tests/CompositeTest.php

<?php

namespace DesignPatterns\Structural\Composite\Tests;

use DesignPatterns\Structural\Composite;
use PHPUnit\Framework\TestCase;

class CompositeTest extends TestCase
{
    public function testRender()
    {
        $form = new Composite\Form();
        $form->addElement(new Composite\TextElement('Email:'));
        $form->addElement(new Composite\InputElement());
        $embed = new Composite\Form();
        $embed->addElement(new Composite\TextElement('Password:'));
        $embed->addElement(new Composite\InputElement());
        $form->addElement($embed);

        // This is just an example, in a real world scenario it is important to remember that web browsers do not
        // currently support nested forms

        $this->assertEquals(
            '<form>Email:<input type="text" /><form>Password:<input type="text" /></form></form>',
            $form->render()
        );
    }
}