Java IntSupplier Example
May 04, 2020
IntSupplier example. The IntSupplier is the functional interface introduced in Java 8 under the java.util.function package. The IntSupplier is the int-producing primitive specialization of Supplier functional interface. The functional method of IntSupplier is getAsInt() which returns integer result. Find the IntSupplier structure from Java doc.
@FunctionalInterface
public interface IntSupplier {
int getAsInt();
}
IntSupplier can be instantiated using lambda expression and method reference.
Here we will provide using IntSupplier in our applications in detail.
Using Lambda Expression
Find the code to instantiateIntSupplier using lambda expression.
IntSupplierWithLE.java
package com.concretepage;
import java.time.LocalDate;
import java.util.function.IntSupplier;
public class IntSupplierWithLE {
public static void main(String[] args) {
IntSupplier yearIs = () -> LocalDate.now().getYear();
System.out.println(yearIs.getAsInt());
IntSupplier msgIs = () -> "Hello World!".length();
System.out.println(msgIs.getAsInt());
IntSupplier is = () -> {
int num1 = 10;
int num2 = 20;
return num1 * num2;
};
System.out.println(is.getAsInt());
}
}
2020 12 200
Using Method Reference
Find the code to instantiateIntSupplier using method reference.
IntSupplierWithMR.java
package com.concretepage;
import java.time.LocalDateTime;
import java.util.function.IntSupplier;
public class IntSupplierWithMR {
public static void main(String[] args) {
IntSupplier monthIs = LocalDateTime.now()::getMonthValue;
System.out.println(monthIs.getAsInt());
IntSupplier dbConIs = AppUtil::noOfDBConnections;
System.out.println(dbConIs.getAsInt());
}
}
class AppUtil {
public static int noOfDBConnections() {
return 20;
}
}
5 20
Passing as Method Parameter
Here we will passIntSupplier as method parameter.
WithMethodParameter.java
package com.concretepage;
import java.util.Random;
import java.util.function.IntSupplier;
import java.util.stream.IntStream;
public class WithMethodParameter {
public static void main(String[] args) {
String id = createTempId(() -> new Random().nextInt(100));
System.out.println(id);
System.out.println("--- With IntStream.generate() ---");
IntStream intStream = IntStream.generate(() -> new Random().nextInt(10)).limit(5);
intStream.forEach(v -> System.out.println(v));
}
static String createTempId(IntSupplier is) {
return "temp-id-" + is.getAsInt();
}
}
temp-id-51 --- With IntStream.generate() --- 8 7 7 6 4
