Delegation Pattern

클�� 해 �� 확��하�� 하��. 하�� 하�� (Delegation) ��. �� 하�� 해�� 클�� 확��킬 �� .

��한, 클�� 하�� 해��, ��하�� 클�� 클�� 해�� Refactoring �� .

ObjectOrientedProgramming �� 할�� . �� .

example) �� VonNeumannAirport �� JuNe �� 1002 �� Pair 하�� JuNe �� 했�� Refactoring �� Delegation.

~cpp 
public class Airport {
	private int _traffic;
	private int [] _arrivalGate;
	private int [] _departureGate;
	private PassengerSet psg;
		
	public int getTraffic() {
		ListIterator iter = psg.passengers.listIterator();
		int [] passenger;
		
		while (iter.hasNext()) {
			passenger = (int [])iter.next();
			movePassenger(passenger[0], 
						passenger[1],
						passenger[2]);
		}
		
		return _traffic;
	}	
	
	public void setArrivalGates(int [] aCity) {
		_arrivalGate = aCity;
	}
	public void setDepartureGates(int [] aCity) {
		_departureGate = aCity;
	}
	
	public int [] getArrivalGates() {
		return _arrivalGate;
	}
	
	public int [] getDepartureGates() {
		return _departureGate;
	}
	public int getDistance(int fromCity, int toCity){
		int distance=java.lang.Math.abs(_getArrivalCityGate(fromCity)
		                             -_getDepartureCityGate(toCity))+1;
		return distance;
	}	

	private void movePassenger(int fromCity, int toCity, int aNumber) {
		_traffic+=getDistance(fromCity,toCity)*aNumber;
	}
	public void setPassengers(PassengerSet psg) {
		this.psg=psg;
	}
}

�� Airport ��. 하�� VonNeumannAirport �� , �� Input �� 해�� Configuration �� Set �� .

�� 하�� 해 �� Airport Code �� Refactoring 하�� 했��. �� 해 Airport �� Configuration �� 해 Configuration �� Extract 하��, �� Delegation 함�� 해�� 한��. (Test Code �� Guard ��할�� 했��)

~cpp 
import java.util.ListIterator;

class Configuration {
	private int [] _arrivalGate;
	private int [] _departureGate;
	private int id;
	
	public void setArrivalGates(int [] aCity) {
		_arrivalGate=aCity;
	}
	public void setDepartureGates(int [] aCity) {
		_departureGate=aCity;	
	}
	
	public int [] getArrivalGates() {
		return _arrivalGate;
	}
	
	public int [] getDepartureGates() {
		return _departureGate;	
	}
	public int getDistance(int fromCity, int toCity){
		int distance=java.lang.Math.abs(_getArrivalCityGate(fromCity)
		                             -_getDepartureCityGate(toCity))+1;
		return distance;
	}	
	public int _findInIntArray(int anInt,int [] anArray) {
		for (int i=0;i<anArray.length;i++) {
			if (anArray[i] == anInt) return i+1;
		}
		return -1;
	}
			
	public int _getArrivalCityGate(int aCity) {
		return _findInIntArray(aCity,getArrivalGates());
	}
	
	public int _getDepartureCityGate(int aCity) {
		return _findInIntArray(aCity,getDepartureGates());
	}
	
	public int getId() {
		return id;
	}
	
	public void setId(int anId) {
		id=anId;
	}
	
}

public class Airport {
	private int _traffic;
	private int [] _arrivalGate;
	private int [] _departureGate;
	private PassengerSet psg;
	private Configuration conf=new Configuration();
		
	public int getTraffic() {
		ListIterator iter = psg.passengers.listIterator();
		int [] passenger;
		
		while (iter.hasNext()) {
			passenger = (int [])iter.next();
			movePassenger(passenger[0], 
						passenger[1],
						passenger[2]);
		}
		
		return _traffic;
	}	
	
	public void setArrivalGates(int [] aCity) {
		conf.setArrivalGates(aCity);
	}
	public void setDepartureGates(int [] aCity) {
		conf.setDepartureGates(aCity);
	}
	
	public int [] getArrivalGates() {
		return conf.getArrivalGates();
	}
	
	public int [] getDepartureGates() {
		return conf.getDepartureGates();
	}
	public int getDistance(int fromCity, int toCity){
		return conf.getDistance(fromCity,toCity);
	}	

	private void movePassenger(int fromCity, int toCity, int aNumber) {
		_traffic+=getDistance(fromCity,toCity)*aNumber;
	}
	public void setPassengers(PassengerSet psg) {
		this.psg=psg;
	}
}

DelegationPattern�� 한 ��, DelegationPattern�� 하�� 클�� 클��트�� 클�� Delegation�� 한�� . ��, �� DelegationPattern�� 클�� 클�� 하�� 한��. �� 하�� 학�� 해�� .

ResponsibilityDrivenDesign , Refactoring, DelegationPattern �� 히 �� . (DesignPattern �� )