Can you provide examples or explanations of the Composite Pattern in relation to this issue?

Issue: Implementing a file system structure where both individual files and directories can be treated uniformly. Solution: The Composite Pattern can be used to represent both individual files and directories as components in a tree structure. This allows operations to be applied recursively to all components, regardless of whether they are files or directories. 

interface FileSystemComponent {
    public function getName(): string;
    public function getSize(): int;
}

class File implements FileSystemComponent {
    private $name;
    private $size;

    public function __construct($name, $size) {
        $this->name = $name;
        $this->size = $size;
    }

    public function getName(): string {
        return $this->name;
    }

    public function getSize(): int {
        return $this->size;
    }
}

class Directory implements FileSystemComponent {
    private $name;
    private $children;

    public function __construct($name) {
        $this->name = $name;
        $this->children = [];
    }

    public function addComponent(FileSystemComponent $component) {
        $this->children[] = $component;
    }

    public function getName(): string {
        return $this->name;
    }

    public function getSize(): int {
        $size = 0;
        foreach ($this->children as $child) {
            $size += $child->getSize();
        }
        return $size;
    }
}

// Example Usage
$file1 = new File("file1.txt", 100);
$file2 = new File("file2.txt", 200);

$dir1 = new Directory("dir1");
$dir1->addComponent($file1);
$dir1->addComponent($file2);

echo $dir1->getSize(); // Outputs: 300

Keywords

Composite Pattern PHP Object-oriented programming Design pattern Composition

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