Skip to content

Instantly share code, notes, and snippets.

@archena
Last active October 20, 2023 21:17
Show Gist options
  • Star 1 You must be signed in to star a gist
  • Fork 1 You must be signed in to fork a gist
  • Save archena/6701388 to your computer and use it in GitHub Desktop.
Save archena/6701388 to your computer and use it in GitHub Desktop.
Generators in Java via Iterator
import java.util.Iterator;
class GeneratorTest {
public static void main(String[] args) {
/**
* A generator for Fibonacci numbers
*/
Generator<Integer> g = new Generator<>(new Sequencer<Integer>() {
private int a = 1, b = 1;
public Integer get() {
final int t = a;
a = b;
b += t;
return t;
}
});
/**
* Output 10 values
*/
for(int i = 0; i < 10; ++i) {
System.out.println(g.next());
}
}
}
/**
* A function with no parameters
*/
interface Sequencer<T> {
T get();
}
/**
* A generator represents an unbounded sequence.
* By using an iterator we can have a lazily-evaluated infinite sequence.
*/
final class Generator<T> implements Iterator<T> {
private final Sequencer<T> sequence;
public Generator(Sequencer<T> sequence) {
this.sequence = sequence;
}
public boolean hasNext() {
return true;
}
public T next() {
return sequence.get();
}
public void remove() {
sequence.get();
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment