public function getContentClass( array $mimeData )
    {
        $upload = new eZContentUpload();

        $classIdentifier = $upload->detectClassIdentifier( $mimeData['name'] );
        $class = eZContentClass::fetchByIdentifier( $classIdentifier );
        if ( !$class instanceof eZContentClass )
        {
            throw new RuntimeException(
                ezpI18n::tr(
                    'extension/ezjscore/ajaxuploader',
                    'Unable to load the class which identifier is "%class",' .
                    ' this is probably a configuration issue in upload.ini.',
                    null, array( '%class' => $classIdentifier )
                )
            );
        }

        $classContent = $this->attribute->attribute( 'class_content' );

        if ( !empty( $classContent['class_constraint_list'] )
                && !in_array( $classIdentifier, $classContent['class_constraint_list'] ) )
        {
            throw new DomainException(
                ezpI18n::tr(
                    'extension/ezjscore/ajaxuploader', 'The file cannot be processed because' .
                    ' it would result in a \'%class\' object and this relation' .
                    ' does not accept this type of object.',
                    null, array( '%class' => $class->attribute( 'name' ) )
                )
            );
        }
        return $class;
    }