Comparable / Comparator - Theater 코딩 이용

https://jeong-pro.tistory.com/m/173 개념참고.

Theater 코딩서 이미 좌석정렬했는데, 가격순 정렬도 보고싶다? 

comparable(cmopareTo)를 수정할 순 없고, 가격순 comparator 추가!

 

Comparable : public class xxxx implement Comparable<>{ ....@override...CompareTo()  } 이용

참고)CompareToIgnoreCase() : 대소문자 무시

 

Comparator : implement 이용 안함.

                  1. comparator type의 object 생성  -(여러개 comparator 생성가능)

                  2. 주로 익명 Class이용하여 compare()이용하여 initialization

                  static final Comparator<Seat> object;         

                  static { object = new Comparator<Seat>()    // initialization

                                                    { @override...........  compare()...........        }          } 

Main Class

Collections.sort(priceSeats, Theatre.PRICE_ORDER);    //collections.sort(list, defined comparator)

 

예제) Theater Class에 가격순정렬 comparator 추가.

 

package com.timbuchalka;

import java.util.*;

public class Theatre {
    private final String theatreName;
    private List<Seat> seats = new ArrayList<>();

    static final Comparator<Seat> PRICE_ORDER;  //comparator type의 object(가격) 생성    V

    //가격순 정렬 정의.        V
    static {             //comparator //anonymous clss 이용해서 특정한 정렬 정의(initialization)
        PRICE_ORDER = new Comparator<Seat>()
        {                                  // 요거 initialzation 쓰면 자동으로 @override 나옴.
            @Override
            public int compare(Seat seat1, Seat seat2) {        //정렬방법 내가 정함.
                if (seat1.getPrice() < seat2.getPrice()) {
                    return -1;          //위치 앞으로
                } else if (seat1.getPrice() > seat2.getPrice()) {   //위치 뒤로
                    return 1;
                } else {
                    return 0;       //가격동일
                }
            }
        };
    }
//constructor 에 가격설정 추가.                V
    public Theatre(String theatreName, int numRows, int seatsPerRow) {
        this.theatreName = theatreName;

        int lastRow = 'A' + (numRows -1);
        for (char row = 'A'; row <= lastRow; row++) { //row : A~H
            for(int seatNum = 1; seatNum <= seatsPerRow; seatNum++) {
                double price = 12.00;           //기본가격 =12

                if((row < 'D') && (seatNum >=4 && seatNum <=9)) {   //<D(4~9) 14                    price = 14.00;
                    price= 14.00;
                } else if((row > 'F') || (seatNum < 4 || seatNum > 9)) {
                    price = 7.00;           //F<(123,10,11,12)
                }

                Seat seat = new Seat(row + String.format("%02d", seatNum), price);
                seats.add(seat);
            }
        }
    }
//getter
    public String getTheatreName() {
        return theatreName;
    }

    public boolean reserveSeat(String seatNumber) {
        Seat requestedSeat = new Seat(seatNumber, 0);
        int foundSeat = Collections.binarySearch(seats, requestedSeat, null);
        if (foundSeat >= 0) {
            return seats.get(foundSeat).reserve();
        } else {
            System.out.println("There is no seat " + seatNumber);
            return false;
        }
    }

    // for testing
    public Collection<Seat> getSeats() {
        return seats;
    }
//InnerClass Seat ......Comparable
    public class Seat implements Comparable<Seat> {
        private final String seatNumber;
        private double price;
        private boolean reserved = false;
//constructor
        public Seat(String seatNumber, double price) {
            this.seatNumber = seatNumber;
            this.price = price;
        }

        @Override
        public int compareTo(Seat seat) {
            return this.seatNumber.compareToIgnoreCase(seat.getSeatNumber());
        }
//method
        public boolean reserve() {
            if(!this.reserved) {
                this.reserved = true;
                System.out.println("Seat " + seatNumber + " reserved");
                return true;
            } else {
                return false;
            }
        }

        public boolean cancel() {
            if(this.reserved) {
                this.reserved = false;
                System.out.println("Reservation of seat " + seatNumber + " cancelled");
                return true;
            } else {
                return false;
            }
        }

        public String getSeatNumber() {
            return seatNumber;
        }
//getter Price          V
        public double getPrice() {
            return price;
        }
    }

}

Main

package com.timbuchalka;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class Main {

    public static void main(String[] args) {
	    Theatre theatre = new Theatre("Olympian", 8, 12);

        if(theatre.reserveSeat("D12")) {
            System.out.println("Please pay for D12");
        } else {
            System.out.println("Seat already reserved");
        }

        if(theatre.reserveSeat("D12")) {
            System.out.println("Please pay for D12");
        } else {
            System.out.println("Seat already reserved");
        }

        if(theatre.reserveSeat("B13")) {
            System.out.println("Please pay for B13");
        } else {
            System.out.println("Seat already reserved");
        }
//separate List, same data 가능                               // V
        List<Theatre.Seat> reverseSeats = new ArrayList<>(theatre.getSeats());
        Collections.reverse(reverseSeats); //좌석 역순
        printList(reverseSeats);


        List<Theatre.Seat> priceSeats = new ArrayList<>(theatre.getSeats());
        priceSeats.add(theatre.new Seat("B00", 13.00));	//innerClass에 추가(constructor).
        priceSeats.add(theatre.new Seat("A00", 13.00));
        Collections.sort(priceSeats, Theatre.PRICE_ORDER); //가격 순         V
        printList(priceSeats);

    }


    public static void printList(List<Theatre.Seat> list) {
        for(Theatre.Seat seat : list) {
            System.out.print(" " + seat.getSeatNumber() + " $" + seat.getPrice());
        }
        System.out.println();
        System.out.println("======================================================================");
    }
}

//Output
D:\IT\JDK\jdk11.0.6_10\bin\java.exe "-javaagent:D:\IT\IDEA\IntelliJ IDEA Community Edition 2020.1\lib\idea_rt.jar=51479:D:\IT\IDEA\IntelliJ IDEA Community Edition 2020.1\bin" -Dfile.encoding=UTF-8 -classpath D:\IT\Java-Collections-Comparable-and-Comparator-Source-code\out\production\Collections com.timbuchalka.Main
Seat D12 reserved
Please pay for D12
Seat already reserved
There is no seat B13
Seat already reserved
 H12 $7.0 H11 $7.0 H10 $7.0 H09 $7.0 H08 $7.0 H07 $7.0 H06 $7.0 H05 $7.0 H04 $7.0 H03 $7.0 H02 $7.0 H01 $7.0 G12 $7.0 G11 $7.0 G10 $7.0 G09 $7.0 G08 $7.0 G07 $7.0 G06 $7.0 G05 $7.0 G04 $7.0 G03 $7.0 G02 $7.0 G01 $7.0 F12 $7.0 F11 $7.0 F10 $7.0 F09 $12.0 F08 $12.0 F07 $12.0 F06 $12.0 F05 $12.0 F04 $12.0 F03 $7.0 F02 $7.0 F01 $7.0 E12 $7.0 E11 $7.0 E10 $7.0 E09 $12.0 E08 $12.0 E07 $12.0 E06 $12.0 E05 $12.0 E04 $12.0 E03 $7.0 E02 $7.0 E01 $7.0 D12 $7.0 D11 $7.0 D10 $7.0 D09 $12.0 D08 $12.0 D07 $12.0 D06 $12.0 D05 $12.0 D04 $12.0 D03 $7.0 D02 $7.0 D01 $7.0 C12 $7.0 C11 $7.0 C10 $7.0 C09 $14.0 C08 $14.0 C07 $14.0 C06 $14.0 C05 $14.0 C04 $14.0 C03 $7.0 C02 $7.0 C01 $7.0 B12 $7.0 B11 $7.0 B10 $7.0 B09 $14.0 B08 $14.0 B07 $14.0 B06 $14.0 B05 $14.0 B04 $14.0 B03 $7.0 B02 $7.0 B01 $7.0 A12 $7.0 A11 $7.0 A10 $7.0 A09 $14.0 A08 $14.0 A07 $14.0 A06 $14.0 A05 $14.0 A04 $14.0 A03 $7.0 A02 $7.0 A01 $7.0
======================================================================
 A01 $7.0 A02 $7.0 A03 $7.0 A10 $7.0 A11 $7.0 A12 $7.0 B01 $7.0 B02 $7.0 B03 $7.0 B10 $7.0 B11 $7.0 B12 $7.0 C01 $7.0 C02 $7.0 C03 $7.0 C10 $7.0 C11 $7.0 C12 $7.0 D01 $7.0 D02 $7.0 D03 $7.0 D10 $7.0 D11 $7.0 D12 $7.0 E01 $7.0 E02 $7.0 E03 $7.0 E10 $7.0 E11 $7.0 E12 $7.0 F01 $7.0 F02 $7.0 F03 $7.0 F10 $7.0 F11 $7.0 F12 $7.0 G01 $7.0 G02 $7.0 G03 $7.0 G04 $7.0 G05 $7.0 G06 $7.0 G07 $7.0 G08 $7.0 G09 $7.0 G10 $7.0 G11 $7.0 G12 $7.0 H01 $7.0 H02 $7.0 H03 $7.0 H04 $7.0 H05 $7.0 H06 $7.0 H07 $7.0 H08 $7.0 H09 $7.0 H10 $7.0 H11 $7.0 H12 $7.0 D04 $12.0 D05 $12.0 D06 $12.0 D07 $12.0 D08 $12.0 D09 $12.0 E04 $12.0 E05 $12.0 E06 $12.0 E07 $12.0 E08 $12.0 E09 $12.0 F04 $12.0 F05 $12.0 F06 $12.0 F07 $12.0 F08 $12.0 F09 $12.0 B00 $13.0 A00 $13.0 A04 $14.0 A05 $14.0 A06 $14.0 A07 $14.0 A08 $14.0 A09 $14.0 B04 $14.0 B05 $14.0 B06 $14.0 B07 $14.0 B08 $14.0 B09 $14.0 C04 $14.0 C05 $14.0 C06 $14.0 C07 $14.0 C08 $14.0 C09 $14.0
======================================================================

Process finished with exit code 0