Java02. ДЗ 03, Лобанов Артём #6
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sproshev
suggested changes
Oct 30, 2016
| import java.util.LinkedList; | ||
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| public final class Collections { | ||
| public static <X, Y> Iterable<Y> map(Iterable<X> stream, Function1<? super X, Y> f) { |
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надо стараться принимать как можно более общий параметр и возращать как можно более конкретный результат. Т.е. в данном случае желательно вернуть List или LinkedList
| public default <Z> Function1<X, Z> compose(Function1<? super Y, ? extends Z> g) { | ||
| return x -> g.apply(Function1.this.apply(x)); | ||
| } | ||
| } |
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все методы и поля внутри интерфейса по умолчанию public, поэтому этот модификатор указывать не надо
| public Y apply(X x); | ||
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| public default <Z> Function1<X, Z> compose(Function1<? super Y, ? extends Z> g) { | ||
| return x -> g.apply(Function1.this.apply(x)); |
| public default Function2<X2, X1, Y> flip() { | ||
| return (x2, x1) -> Function2.this.apply(x1, x2); | ||
| } | ||
| } |
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| public interface Predicate<X> extends Function1<X, Boolean> { | ||
| Predicate ALWAYS_TRUE = x -> true; | ||
| Predicate ALWAYS_FALSE = x -> false; |
| public default Predicate<X> not() { | ||
| return x -> !Predicate.this.apply(x); | ||
| } | ||
| } |
| assertEquals("(1 + (2 + (3 + (4 + (5 + 0)))))", Collections.foldr(f, "0", Arrays.asList(1, 2, 3, 4, 5))); | ||
| } | ||
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| } No newline at end of file |
| import static ru.spbau.lobanov.functional.PredicateTest.checkContents; | ||
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| public class CollectionsTest { | ||
| private static final Iterable<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10); |
| import static org.junit.Assert.*; | ||
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| public class PredicateTest { | ||
| private static final Iterable<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15); |
| return !iterator.hasNext(); | ||
| } | ||
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| } No newline at end of file |
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10 |
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