1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
|
package org.zwobble.couscous.util;
import com.google.common.collect.Lists;
import java.util.Iterator;
import java.util.List;
import java.util.function.BiFunction;
public class Fold {
public static <T, V> V foldLeft(Iterable<T> iterable, V initialValue, BiFunction<V, T, V> function) {
V value = initialValue;
for (T element : iterable) {
value = function.apply(value, element);
}
return value;
}
public static <T> T foldLeft(Iterable<T> iterable, BiFunction<T, T, T> function) {
Iterator<T> iterator = iterable.iterator();
T value = iterator.next();
while (iterator.hasNext()) {
value = function.apply(value, iterator.next());
}
return value;
}
public static <T, V> V foldRight(List<T> iterable, V initialValue, BiFunction<V, T, V> function) {
return foldLeft(Lists.reverse(iterable), initialValue, function);
}
}
|
