Abstract Tree Model

[Ben Woodhead]

Hey Everybody,

I was thinking of a generic interface for dealing with tree'd data
such as xml or json. The data is loaded into an abstract tree model
that uses magic methods to expose the data. Here is an example of the
interface:

// Create a tree
$root = new AbstractTreeModel("Root");

// Create a path with a book
$root->books->book1->name = "Test Book1";
$root->books->book1->_attributes->type = "Soft Cover";

// Add another book to the books path
$root->books->book2->name = "Code Complete";
$root->books->book2->_attributes->type = "Soft Cover";

// Create a new path with a magazine
$root->magazines->page1->name = "Tech Review";
$root->magazines->page1->_attributes->type = "Magazine";

// Loop through an array of books
foreach( $root->books as $book) {
echo($book->name);
}

Let me know what you think,
Ben
The code:

/**
* Abstract Tree Model represents data trees in a php friendly way.
*/
class AbstractTreeModel
{
private $mName;
private $mValue;
private $mAttributes;
private $mChildren;

/**
* Default constructor that requires a node name
* @param type $name
* @param type $value
*/
public function __construct($name, $value=null)
{
$this->mName = $name;
$this->mValue = $value;
$this->mAttributes = new AbstractAttributes();
$this->mChildren = array();
}

/**
* Magic Get Method that return abstract tree models or attributes
based on the method name
* @param type $name
* @return type
*/
public function __get($name)
{
if ( $name == "_attributes") {
return $this->mAttributes;
}

if ( ! array_key_exists($name, $this->mChildren))
{
$this->mChildren[$name] = new AbstractTreeModel($name);
}
return $this->mChildren[$name];
}

/**
* Magic Set Method that stores a value based on the method name
* @param type $name
* @param type $value
*/
public function __set($name, $value)
{
$this->mValue = $value;
}

/**
* Direct calls to the class will return an array of children.
* @return type
*/
public function __invoke()
{
return $this->mChildren;
}
}

/**
* AbstractAttributes helps with setting attributes using magic methods.
*/
class AbstractAttributes
{
private $mData = array();

/**
* Magic Get returns the value using the method name as a key.
* @param type $name
* @return type
*/
public function __get($name)
{
if ( !array_key_exists($name, $this->mData) )
{
return null;
}
return $this->mData[$name];
}

/**
* Magic Set stores the value using the method name as a key.
* @param type $name
* @param type $value
*/
public function __set($name, $value)
{
$this->mData[$name] = $value;
}

/**
* Tree printing helper
* @return string
*/
public function printAttributes()
{
$string = null;
foreach( $this->mData as $key => $value ) {
$string .= $key . ": ". $value . "<br>";
}
return $string;
}
}