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Factories are a natural partner with anonymous inner classes. With a factory that returns anonymous inner classes, we can instantiate unique objects with unique behaviors. If the factory method takes in parameters, there local variables can be used to alter the resultant object's behavior, a process called " currying " (named after the famous mathematician/computer scientist Haskell Curry ). The objects made by the factory are then sent off to various odd and sundry different parts of our OO system but all the while retaining their closures, which were determined at the time of their instantiation. Thus they retain the ability to communicate back to the factory that made them even though they are being used in another part of the system that knows nothing about the factory. We like to call these " spy objects " because they act like spies from the factory. This gives us powerful communications even though the system is decoupled.

This is the last piece of our abstraction puzzle! We have

  1. Abstract Structure -- abstract classes, interfaces
  2. Abstract Behavior -- abstract methods, strategies, visitors.
  3. Abstract Construction -- factories
  4. Abstract Environments -- anonymous inner classes, closures.


Example 1: reversing a list using factory and anonymous inner class helper

Write Reverse such that it takes one parameter, the IListFactory , but such that its helper only takes one parameter (other than the host list) which is the accumulated list.

public class Reverse implements IListAlgo {public static final Reverse Singleton = new Reverse();private Reverse() {}public Object emptyCase(IMTList host0, Object... fac) { return ((IListFactory)fac[0]).makeEmptyList(); }public Object nonEmptyCase(INEList host0, Object... fac) {final IListFactory f = (IListFactory) fac[0]; // final so that the anon. inner// class can access it.return host0.getRest().execute(new IListAlgo() {public Object emptyCase(IMTList host1, Object... acc) { return acc[0]; }public Object nonEmptyCase(INEList host1, Object... acc) {return host1.getRest().execute(this, f.makeNEList(host1.getFirst(), (IList) acc[0])); }},f.makeNEList(host0.getFirst(), f.makeEmptyList())); }}

Example 2: ant world

Imagine a world of ants that live in a one-dimensional space. A queen ant can make a bunch of worker ants. Each time she gives birth to a worker ant, she gives it a name. A worker ant can always tell what its name is. A worker ant from a particular colony can always calculate its distance from its queen. A worker ant can also move its queen to a different location. Wherever the queen moves to, ALL of her workers always know their relative distance from her. We want to keep track of all the ants in our ant world and all the ants in each of the existing colonies. We want to model the fact that each queen produces its own worker ants, each one which can move its queen around without telling the other ants in the same colony, yet ALL of the ants in the same colony would know where their queen is.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Principles of object-oriented programming. OpenStax CNX. May 10, 2013 Download for free at http://legacy.cnx.org/content/col10213/1.37
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