Properties of aggregation (cont.)
nSometimes, other objects are responsible for creating the parts and putting them together.
nExample:
npublic class Assembler {…
n  public Car createCar () {
n   Chassis theChassis;
n   Engine theEngine;
n   …
n   theChassis =    cassisFactory.createChassis();
n    theEngine =
n engineFactory.createEngine();
n   …
n   theCar =
n new Car(theChassis, theEngine,…)
n   return the Car;
n  }
n}