Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to use method references with Generics in Java?
The method references are introduced in Java 8 similar to lambda expression. It can allow us to reference methods or constructors without executing them. The method references and lambda expressions require a target type that consists of a compatible functional interface. We can also use a method reference with generic classes and generic methods in java.
Example
interface MyFunc<T> {
int func(T[] vals, T v);
}
class MyArrayOps {
static<T> int countMatching(T[] vals, T v) {
int count = 0;
for(int i=0; i < vals.length; i++)
if(vals[i] == v)
count++;
return count;
}
}
public class GenericMethodRefTest {
static<T> int myOp(MyFunc f, T[] vals, T v) {
return f.func(v als, v);
}
public static void main(String args[]) {
Integer[] vals = { 1, 2, 3, 4, 2, 3, 4, 4, 5 };
String[] strs = { "One", "Two", "Three", "Two" };
int count;
count = myOp(MyArrayOps :: countMatching, vals, 4);
System.out.println("vals contains " + count + " 4s");
count = myOp(MyArrayOps :: countMatching, strs, "Two");
System.out.println("strs contains " + count + " Twos");
}
}Output
vals contains 3 4s strs contains 2 Twos
Updated on: 11-Jul-2020
566 Views
Advertisements