Berikut adalah contoh hal-hal baru yang bisa dilakukan dengan java 8.
A. Comparator, Sorting dengan class Collection
---
public class Test_1 {
public static void main(String[] args) {
List stringList = new ArrayList<>();
stringList.add("fdasadQ");
stringList.add("qfdasadQ");
stringList.add("fwwdasadQ");
stringList.add("sfdfsfdasadQ");
stringList.add("4543fdasadQ");
System.out.println(stringList);
// Collections.sort(stringList); //
// Collections.sort(stringList, (s1, s2) -> s1.compareTo(s2));
Collections.sort(stringList, (s1, s2) -> s2.compareTo(s1));
//decending
System.out.println("setelah di sorting");
System.out.println(stringList);
}
}
result:
[fdasadQ, qfdasadQ, fwwdasadQ, sfdfsfdasadQ, 4543fdasadQ]
setelah di sorting
[sfdfsfdasadQ, qfdasadQ, fwwdasadQ, fdasadQ, 4543fdasadQ]
---
B. Functional Interface
public class Test_1 {
public static void main(String[] args) {
TesPrin tesPrin = () -> System.out.println("cetak terserah");
TesPrinParam tesPrinParam = (ss) -> System.out.println("cetak "+ss);
System.out.println("memanggil default method di interface >>> "+tesPrin.srqt(9));
tesPrin.prin();
tesPrinParam.prin("param");
Operasi tambah = (int bilA,int bilB)-> bilA + bilB;
Operasi kurang = (int bilA,int bilB)-> bilA - bilB;
Operasi kali = (int bilA,int bilB)-> bilA * bilB;
Operasi bagi = (int bilA,int bilB)-> bilA / bilB;
System.out.println(kalkulator(3,4, tambah));
System.out.println(kalkulator(3,4, kurang));
System.out.println(kalkulator(3,4, kali));
System.out.println(kalkulator(3,4, bagi));
}
interface TesPrin{
void prin();
default double srqt(double angka){
return Math.sqrt(angka);
}
}
interface TesPrinParam{
void prin(String param);
}
interface Operasi{
int aksi(int bilA,int bilB);
}
public static int kalkulator(int bilA,int bilB, Operasi operasi){
return operasi.aksi(bilA,bilB);
}
}
result:
cetak terserah
cetak param
memanggil default method di interface >>> 3.0
cetak terserah
cetak param
7
-1
12
0
C. For Each
public class Test_1 {
public static void main(String[] args) {
List<Siswa> siswaList = new ArrayList<>();
siswaList.add(new Siswa("Sucipto", "Pintar"));
siswaList.add(new Siswa("Elnanda", "Pintar Sekali"));
siswaList.add(new Siswa("Ujup", "1"));
siswaList.add(new Siswa("Nazar", "1"));
siswaList.add(new Siswa("Suseno", "XL"));
System.out.println("forEach Siswa");
siswaList.forEach(siswa -> System.out.println(siswa));
System.out.println();
siswaList.forEach(siswa -> {
if (siswa!=null && siswa.getName().equals("Sucipto"))
System.out.println(siswa);
});
}
}
class Siswa{
String name;
String kelas;
// get set
@Override public String toString() {
return "Siswa{" +
"name='" + name + '\'' +
", kelas='" + kelas + '\'' +
'}';
}
}
D. Stream
siswaList.stream()
.filter(siswa -> siswa.getKelas().contains("Pintar"))
.forEach(System.out::println);
List<Siswa> siswaList1 = siswaList.stream()
.filter(siswa -> siswa.getKelas().contains("X"))
.collect(Collectors.toList());
siswaList1.forEach(System.out::println);
steam grouping
Map<String, List<Siswa>> collect = siswaList.stream().collect(Collectors.groupingBy(Siswa::getName));
collect.forEach(
(s, siswas) -> {
System.out.println(s+"|"+siswas);
}
);
E. Bla bla
F. Bla bla
G. Bla bla
