The document discusses examples of using the Comparable and Comparator interfaces in Java. It provides code for a Mahasiswa class that implements Comparable to sort students by name, ID number, and GPA. It also includes code for an IPKComparator class that uses the Comparator interface to sort an array of Mahasiswa objects by GPA. Similarly, it provides code for a Buah class and StockComparator to sort an array of fruit by stock level.

1. LATIHAN 4
COMPARABLE DAN COMPARATOR
1. Latihan 1 : Sebutkan class-class yang mengimplementasikan interface Comparable.
Jawab: Class - class yang dibuat sendiri maupun class - class yang tersedia di java
collection dapat mengimplementasikan interface Comparable yang terdapat dalam
package java.lang.Comparable..
2. Latihan 2 : Kembangkan untuk Class Mahasiswa dengan memberikan variabel baru
berupa nilai IPK (double), selanjutkan lakukan pengurutan data Mahasiswa
berdasarkan nrp, nama dan nilai IPK (menggunakan Comparable dan Comparator)
Source Code:
Mahasiswa.java
public class Mahasiswa implements Comparable {
private String nrp ;
private String nama ;
private String IPK;
public Mahasiswa(String nrp, String nama, String IPK) {
this.nrp = nrp;
this.nama = nama;
this.IPK = IPK;
}
public String getNama() {
return nama;
}
public void setNama(String nama) {
this.nama = nama;
}
public String getNrp() {
return nrp;
}
public void setNrp(String nrp) {
this.nrp = nrp;
}
public String getIPK() {
return IPK;
}
public void setIPK(String IPK) {
this.IPK = IPK;
}
@Override
public String toString() {
return "NRPt:"+nrp+"ttNamat: "+nama+"ttIPKt: "+IPK+"n";
}
@Override
public int compareTo(Object o) {

2. throw new UnsupportedOperationException("Not supported yet."); //To change
body of generated methods, choose Tools | Templates.
}
}
IPKComparator.java
import java.util.Comparator;
public class IPKComparator implements Comparator {
@Override
public int compare(Object o1, Object o2) {
Mahasiswa m1 = (Mahasiswa) o1;
Mahasiswa m2 = (Mahasiswa) o2;
return m1.getIPK().compareTo(m2.getIPK());
}
}
Latihan2.java
import java.util.Arrays;
public class Latihan2 {
public static void main(String[] args) {
Mahasiswa dataMhs[] = {new Mahasiswa("05", "Cahya","3.56"),new
Mahasiswa("04", "Rudi","3.8"),
new Mahasiswa("01", "Endah","3.76"),new Mahasiswa("03", "Rita","3.87"),new
Mahasiswa("02", "Tika","3.88")};
System.out.println("SEBELUM SORTING");
System.out.println(Arrays.toString(dataMhs));
Arrays.sort(dataMhs, new IPKComparator());
System.out.println("nSESUDAH SORTING");
System.out.println(Arrays.toString(dataMhs));
}
}

3. Output:
3. Latihan 3 : Pada Supermarket Buah, terdapat beberapa macam buah dan informasi
stock dari buah tersebut. Terdapat menu penjualan (supermarket ke konsumen) dan
pembelian (supermarket ke pemasok) (menggunakan Comparable dan Comparator)
Source Code:
Buah.java
public class Buah implements Comparable {
private String namabuah ;
private int stock ;
public Buah(String namabuah,int stock) {
this.namabuah = namabuah;
this.stock=stock;
}
public String getNamaBuah() {
return namabuah;
}
public int getStock() {
return stock;
}
@Override
public String toString() {
return "Buaht: "+namabuah+"ttStockt: "+stock+"n";
}

4. @Override
public int compareTo(Object o) {
throw new UnsupportedOperationException("Not supported yet."); //To change body
of generated methods, choose Tools | Templates.
}
}
StockComparator.java:
import java.util.Comparator;
public class StockComparator implements Comparator {
@Override
public int compare(Object o1, Object o2) {
Buah m1 = (Buah) o1;
Buah m2 = (Buah) o2;
return m1.getStock().compareTo(m2.getStock());
}
}
Latihan3.java:
import java.util.*;
public class Latihan3{
public static void main(String[] args) {
Buah databuah[] = {new Buah("Melon","160"), new Buah("Aprikot","100"), new
Buah("Alpukat","198"),new Buah("Durian","128")};
System.out.println("SEBELUM DI SORT");
System.out.println(Arrays.toString(databuah));
Arrays.sort(databuah, new StockComparator());
System.out.println("nSESUDAH SORTING");
System.out.println(Arrays.toString(databuah));
}
}

5. Output:
4.
Source Code:
import java.util.*;
public class Latihan4 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Masukkan kata: ");
String kata = input.nextLine();
Set<word> s = new TreeSet<>();
for(String y : kata.split(" ")){
if (!s.add(new word(y)))
System.out.println("Duplicate detected: " +y);
}
System.out.println(s.size() + " distinct words: " +s);
}
}
class word implements Comparable{
private String kata;
public word(String kata){
this.kata=kata;

6. }
public String getKata(){
return this.kata;
}
@Override
public String toString(){
return kata;
}
@Override
public int compareTo(Object o) {
return this.kata.toLowerCase().compareTo(((word) o).getKata().toLowerCase());
}
}
Output: