class Raptor {
   constructor(build) {
      if (arguments.length === 1 && this.validateBuild(build)) {
         let specimenId = build.specimenId;
         let speed = build.speed;
         let plumage = build.plumage;
         Object.defineProperties(this, {
            '_specimenId': {
               value: specimenId,
               writable: false
            },
            '_speed': {
               value: speed,
               writable: false
            },
            '_plumage': {
               value: plumage,
               writable: false
            }
         });
      }
   }
   validateBuild(build) {
      return (String(build.constructor) === String(Raptor.Builder));
   }
   static get Builder() {
      class Builder {
         constructor(specimenId) {
            this.specimenId = specimenId;
         }
         withSpeed(speed) {
            this.speed = speed;
            return this;
         }
         withPlumage(plumage) {
            this.plumage = plumage;
            return this;
         }
         build() {
            return new Raptor(this);
         }
      }
      return Builder;