The Streams are the flow of data, Streams can be finite and infinite. Finite streams can be generated in multiple ways such as List, Map etc which we have already seen before.
Java 8 provides functions to generate infinite streams as well, it will keep on providing new elements unless not stopped or a limit is applied.
Generate
Generate functions defined in Stream class takes a Supplier function which will generate the next element of Infinite Stream.
package org.wesome.java8;
import java.util.Random;
import java.util.stream.Stream;
class Apple {
public static void main(String args[]) {
/*---------------Math random---------------*/
Stream.generate(Math::random).limit(5).forEach(System.out::println);
/*---------------Random---------------*/
Stream.generate(Random::new).map(Random::nextInt).limit(5).forEach(System.out::println);
}
}Iterate
The Iterate method takes 2 parameters, seed which is the initial value of the infinite stream, and a Unary operator, which will take a single input, process it and return the single output.
package org.wesome.java8;
import java.util.stream.Stream;
class Apple {
public static void main(String args[]) {
/*-------------------------iterate-------------------------*/
Stream.iterate(1, i -> i + 1).limit(5).forEach(System.out::println);
}
}Infinite streams are majorly used where the end is not fixed or bound. for example, find the first 10 elements which are divisible by 2,3,4 and 5
package org.wesome.java8;
import java.util.stream.IntStream;
public class Apple {
public static void main(String[] args) {
int limit = 10;
IntStream.iterate(1, value -> value + 1)
.filter(value -> value % 2 == 0)
.filter(value -> value % 3 == 0)
.filter(value -> value % 4 == 0)
.filter(value -> value % 5 == 0)
.limit(limit)
.forEach(System.out::println);
}
}
