code: function UMLLink() {
          UMLUndirectedRelationship.apply(this, arguments);
  
          /** @member {UMLLinkEnd} */
          this.end1 = new UMLLinkEnd();
          this.end1._parent = this;
  
          /** @member {UMLLinkEnd} */
          this.end2 = new UMLLinkEnd();
          this.end2._parent = this;
  
          /** @member {UMLAssociation} */
          this.association = null;
      }
docs: UMLLink
  @constructor
  @extends UMLUndirectedRelationship