fj.data.fingertrees.Two Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of functionaljava Show documentation
Show all versions of functionaljava Show documentation
Functional Java is an open source library that supports closures for the Java programming language
package fj.data.fingertrees;
import fj.P;
import fj.P2;
import fj.P3;
import fj.Show;
import fj.data.Option;
import fj.data.Stream;
import fj.data.vector.V2;
import fj.F;
import static fj.data.Option.none;
import static fj.data.Option.some;
import static fj.data.fingertrees.FingerTree.mkTree;
/**
* A two-element prefix or suffix of a finger tree.
*/
public final class Two extends Digit {
private final V2 as;
Two(final Measured m, final V2 as) {
super(m);
this.as = as;
}
public B foldRight(final F> aff, final B z) {
return aff.f(as._1()).f(aff.f(as._2()).f(z));
}
public B foldLeft(final F> bff, final B z) {
return as.toStream().foldLeft(bff, z);
}
@Override public B match(
final F, B> one, final F, B> two, final F, B> three,
final F, B> four) {
return two.f(this);
}
/**
* Returns the elements of this digit as a vector.
*
* @return the elements of this digit as a vector.
*/
public V2 values() {
return as;
}
@Override P3>, A, Option>> split1(final F predicate, final V acc) {
final Measured m = measured();
final MakeTree mk = mkTree(m);
if (predicate.f(m.sum(acc, m.measure().f(as._1())))) {
return P.p(none(), as._1(), some(mk.one(as._2())));
} else {
return P.p(some(mk.one(as._1())), as._2(), none());
}
}
@Override public P2 lookup(F o, int i) {
final F m = measured().measure();
final int s1 = o.f(m.f(as._1()));
if (i < s1) {
return P.p(i, as._1());
} else {
return P.p(i - s1, as._2());
}
}
@Override
public int length() {
return 2;
}
public String toString() {
return Show.digitShow(Show.anyShow(), Show.anyShow()).showS(this);
}
public Stream toStream() {
return values().toStream();
}
}