Bound Instance Method Reference
Description
Bound Receiver receiver has the following form:
instance::MethodName
In their following code we use the buildin system functional
interface Supplier as the lambda expression type.
At first we define a lambda expression in a normal way. The lambda expression accepts no parameter and returns the length of a string 'java2s.com'
Then we create a String instance with 'java2s.com' and use its length method as the instance method reference.
Bound means we already specify the instance.
Example 1
The following example shows how to use bound receiver and method with no parameters to create Instance Method References.
import java.util.function.Supplier;
/*from w ww.j a va 2 s .c o m*/
public class Main{
public static void main(String[] argv){
Supplier<Integer> supplier = () -> "java2s.com".length();
System.out.println(supplier.get());
Supplier<Integer> supplier1 = "java2s.com"::length;
System.out.println(supplier1.get());
}
}
The code above generates the following result.
Example 2
The following example shows how to use bound receiver and method with parameters to create Instance Method References.
import java.util.function.Consumer;
/*ww w . ja va 2s . c om*/
public class Main{
public static void main(String[] argv){
Util util = new Util();
Consumer<String> consumer = str -> util.print(str);
consumer.accept("Hello");
Consumer<String> consumer1 = util::print;
consumer1.accept("java2s.com");
util.debug();
}
}
class Util{
private int count=0;
public void print(String s){
System.out.println(s);
count++;
}
public void debug(){
System.out.println("count:" + count);
}
}
The code above generates the following result.
