[gruffi]

Добрый день, форумчане.
Помогите пожалуйста. Не могу обратиться к свойствам объекта из метода объекта. Есть объект:

var Shape = 
{
    CIRCLE_SHAPE:     4,
    LINE_SHAPE:       5,
    POLYGON_SHAPE:    6,
    RECTANGLE_SHAPE:  7,
 
    // properties
    _map:   null,
    _id:    null,
    _layer: null,
    _shape: null,
    _type:  null,
    
    // methods
    create: function(map, type, latlngs)
    {
        if(this._shape == null)
        {
            this._map  = map;
            this._type = (type == 'circle')?this.CIRCLE_SHAPE:(type == 'polyline')?
                               this.LINE_SHAPE:(type == 'polygon')?this.POLYGON_SHAPE:
                               (type == 'rectangle')?this.RECTANGLE_SHAPE:null;
            
            switch(this._type)
            {
                case this.CIRCLE_SHAPE:
                    console.log('shape: circle');
                    console.log('latlngs: ' + latlngs);
                    this._shape = L.circle(latlngs, latlngs.distanceTo(latlngs));
                break;
                
                case this.LINE_SHAPE:
                    console.log('shape: polyline');
                break;
                
                case this.POLYGON_SHAPE:
                    console.log('shape: polygon');
                break;
                
                case this.RECTANGLE_SHAPE:
                    console.log('shape: rectangle');
                break;
            }
            
            if(this._shape != null)
            {
                console.log('shape is created');
                this._id = BEGIN_NUMBER_SHAPE++;
                
                this._layer = L.featureGroup();
                this._map.addLayer(this._layer);
                this._layer.addLayer(this._shape);
            }
            
            this._map.on('click', this._onMouseClick);
            this._map.on('mousemove', this._onMouseMove);
            this._map.on('contextmenu', this._onMouseContextMenu);
        }
    },
    
    _onMouseClick: function(e)
    {
        console.log('_onMouseClick');
        console.log('current number shape: ' + this._id);
        console.log('type shape: ' + this._type);
    },
    
    _onMouseMove: function(e)
    {
        console.log('_onMouseMove');
    },
    
    _onMouseContextMenu: function(e)
    {
        console.log('_onMouseContextMenu');
    }
}

Вывод при клике мыши:

_onMouseClick
current number shape: undefined
type shape: undefined

Почему я не могу получить значения этих свойств?
Спасибо.