2つのPHPオブジェクトをマージする最良の方法は？

$obj_merged = (object) array_merge((array) $obj1, (array) $obj2);

$obj_merged = (object) array_merge((array) $obj1, (array) $obj2);

class Compositor {
  private $obj_a;
  private $obj_b;

  public function __construct($obj_a, $obj_b) {
    $this->obj_a = $obj_a;
    $this->obj_b = $obj_b;
  }

  public function __get($attrib_name) {
    if ($this->obj_a->$attrib_name) {
       return $this->obj_a->$attrib_name;
    } else {
       return $this->obj_b->$attrib_name;
    }
  }
}

foreach($objectA as $k => $v) $objectB->$k = $v;

class Compositor {

    protected $composite = array();
    protected $use_reference;
    protected $first_precedence;

    /**
     * __construct, Constructor
     *
     * Used to set options.
     *
     * @param bool $use_reference whether to use a reference (TRUE) or to copy the object (FALSE) [default]
     * @param bool $first_precedence whether the first entry takes precedence (TRUE) or last entry takes precedence (FALSE) [default]
     */
    public function __construct($use_reference = FALSE, $first_precedence = FALSE) {
        // Use a reference
        $this->use_reference = $use_reference === TRUE ? TRUE : FALSE;
        $this->first_precedence = $first_precedence === TRUE ? TRUE : FALSE;

    }

    /**
     * Merge, used to merge multiple objects stored in an array
     *
     * This is used to *start* the merge or to merge an array of objects.
     * It is not needed to start the merge, but visually is nice.
     *
     * @param object[]|object $objects array of objects to merge or a single object
     * @return object the instance to enable linking
     */

    public function & merge() {
        $objects = func_get_args();
        // Each object
        foreach($objects as &$object) $this->with($object);
        // Garbage collection
        unset($object);

        // Return $this instance
        return $this;
    }

    /**
     * With, used to merge a singluar object
     *
     * Used to add an object to the composition
     *
     * @param object $object an object to merge
     * @return object the instance to enable linking
     */
    public function & with(&$object) {
        // An object
        if(is_object($object)) {
            // Reference
            if($this->use_reference) {
                if($this->first_precedence) array_push($this->composite, $object);
                else array_unshift($this->composite, $object);
            }
            // Clone
            else {
                if($this->first_precedence) array_push($this->composite, clone $object);
                else array_unshift($this->composite, clone $object);
            }
        }

        // Return $this instance
        return $this;
    }

    /**
     * __get, retrieves the psudo merged object
     *
     * @param string $name name of the variable in the object
     * @return mixed returns a reference to the requested variable
     *
     */
    public function & __get($name) {
        $return = NULL;
        foreach($this->composite as &$object) {
            if(isset($object->$name)) {
                $return =& $object->$name;
                break;
            }
        }
        // Garbage collection
        unset($object);

        return $return;
    }
}

$obj = new Compositor(use_reference, first_precedence);
$obj->merge([object $object [, object $object [, object $...]]]);
$obj->with([object $object]);

$obj1 = new stdClass();
$obj1->a = 'obj1:a';
$obj1->b = 'obj1:b';
$obj1->c = 'obj1:c';

$obj2 = new stdClass();
$obj2->a = 'obj2:a';
$obj2->b = 'obj2:b';
$obj2->d = 'obj2:d';

$obj3 = new Compositor();
$obj3->merge($obj1, $obj2);
$obj1->c = '#obj1:c';
var_dump($obj3->a, $obj3->b, $obj3->c, $obj3->d);
// obj2:a, obj2:b, obj1:c, obj2:d
$obj1->c;

$obj3 = new Compositor(TRUE);
$obj3->merge($obj1)->with($obj2);
$obj1->c = '#obj1:c';
var_dump($obj3->a, $obj3->b, $obj3->c, $obj3->d);
// obj1:a, obj1:b, obj1:c, obj2:d
$obj1->c = 'obj1:c';

$obj3 = new Compositor(FALSE, TRUE);
$obj3->with($obj1)->with($obj2);
$obj1->c = '#obj1:c';
var_dump($obj3->a, $obj3->b, $obj3->c, $obj3->d);
// obj1:a, obj1:b, #obj1:c, obj2:d
$obj1->c = 'obj1:c';

foreach($objB AS $var=>$value){
    $objA->$var = $value;
}

class combinator{
function __construct(){       
    $this->melt =  array_reverse(func_get_args());
      // array_reverse is to replicate natural overide
}
public function __call($method,$args){
    forEach($this->melt as $o){
        if(method_exists($o, $method)){
            return call_user_func_array([$o,$method], $args);
            //return $o->$method($args);
            }
        }
    }
public function __get($prop){
        foreach($this->melt as $o){
          if(isset($o->$prop))return $o->$prop;
        }
        return 'undefined';
    } 
}

class c1{
    public $pc1='pc1';
    function mc1($a,$b){echo __METHOD__." ".($a+$b);}
}
class c2{
    public $pc2='pc2';
    function mc2(){echo __CLASS__." ".__METHOD__;}
}

$comb=new combinator(new c1, new c2);

$comb->mc1(1,2);
$comb->non_existing_method();  //  silent
echo $comb->pc2;

function merge_obj(){
    foreach(func_get_args() as $a){
        $objects[]=(array)$a;
    }
    return (object)call_user_func_array('array_merge', $objects);
}

class MergeBase extends ArrayObject
{
     public final function merge( Array $toMerge )
     {
          $this->exchangeArray( array_merge( $this->getArrayCopy(), $toMerge ) );
     }
 }

 $base = new MergeBase();

 $base[] = 1;
 $base[] = 2;

 $toMerge = [ 3,4,5, ];

 $base->merge( $toMerge );

//Not the result of a method
$obj1->extra = new Class2();

//The result of a method, for instance a factory class
$obj1->extra =& Factory::getInstance('Class2');

function copy_properties($from, $to, $fields = null) {
    // copies properties/elements (overwrites duplicates)
    // can take arrays or objects 
    // if fields is set (an array), will only copy keys listed in that array
    // returns $to with the added/replaced properties/keys
    $from_array = is_array($from) ? $from : get_object_vars($from);
    foreach($from_array as $key => $val) {
        if(!is_array($fields) or in_array($key, $fields)) {
            if(is_object($to)) {
                $to->$key = $val;
            } else {
                $to[$key] = $val;
            }
        }
    }
    return($to);
}

function flatten($array, $preserve_keys=1, &$out = array(), $isobject=0) {
        # Flatten a multidimensional array to one dimension, optionally preserving keys.
        #
        # $array - the array to flatten
        # $preserve_keys - 0 (default) to not preserve keys, 1 to preserve string keys only, 2 to preserve all keys
        # $out - internal use argument for recursion
        # $isobject - is internally set in order to remember if we're using an object or array
        if(is_array($array) || $isobject==1)
        foreach($array as $key => $child)
            if(is_array($child))
                $out = Functions::flatten($child, $preserve_keys, $out, 1); // replace "Functions" with the name of your class
            elseif($preserve_keys + is_string($key) > 1)
                $out[$key] = $child;
            else
                $out[] = $child;

        if(is_object($array) || $isobject==2)
        if(!is_object($out)){$out = new stdClass();}
        foreach($array as $key => $child)
            if(is_object($child))
                $out = Functions::flatten($child, $preserve_keys, $out, 2); // replace "Functions" with the name of your class
            elseif($preserve_keys + is_string($key) > 1)
                $out->$key = $child;
            else
                $out = $child;

        return $out;
}

abstract class Util {
    public static function object_to_array($d) {
        if (is_object($d))
            $d = get_object_vars($d);

        return is_array($d) ? array_map(__METHOD__, $d) : $d;
    }

    public static function array_to_object($d) {
        return is_array($d) ? (object) array_map(__METHOD__, $d) : $d;
    }
}

function object_to_array($d) {
    if (is_object($d))
        $d = get_object_vars($d);

    return is_array($d) ? array_map(__FUNCTION__, $d) : $d;
}

function array_to_object($d) {
    return is_array($d) ? (object) array_map(__FUNCTION__, $d) : $d;
}