public void setMaterial(String material) { 
        switch(material) {
            case "mur.":    this.material = Material.MUR; break;
            case "drewn.":  this.material = Material.DRE; break;
            case "szach.":  this.material = Material.SZACH; break;
            case "met.":    this.material = Material.MET; break;  
            case "mur.-drewn.": this.material = Material.MUR_DRE; break;
            case "mur.-met.":   this.material = Material.MUR_MET; break;
        }
    };