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| 1 | +package challenge51_60; |
| 2 | + |
| 3 | +import java.util.List; |
| 4 | +import java.util.function.Predicate; |
| 5 | + |
| 6 | +/** |
| 7 | + * stream reduce operation. |
| 8 | + * filter and allmatch regarding the intermediate operation behaviour. |
| 9 | + * // TODO: 04/12/2019 understand all the overloaded reduce methods. |
| 10 | + * |
| 11 | + * Optional<T> reduce(BinaryOperator<T> accumulator) |
| 12 | + * T reduce(T identity, BinaryOperator<T> accumulator) |
| 13 | + * |
| 14 | + * Identity : initial value of the reduction, and in the same time |
| 15 | + * a default result if the stream is empty. |
| 16 | + * |
| 17 | + * Accumulator : A function that takes two parameters, BinaryOperator<T> extends BiFunction<T,T,T> |
| 18 | + * the two parameters are : the partial result of the reduction operation |
| 19 | + * and the next element of the stream. |
| 20 | + */ |
| 21 | +public class Challenge_60 { |
| 22 | + public static void main( String[] args ) { |
| 23 | + List<String> list = List.of("Neo", "Morpheus", "Oracle", "Trinity", "Neo"); |
| 24 | + Predicate<String> neoSearch = str -> { |
| 25 | + System.out.println("Agent Smith is looking for Neo..."); |
| 26 | + return str.contains("Neo"); |
| 27 | + }; |
| 28 | + var binaryNumbers = List.of(1, 0, 1, 1).stream(); |
| 29 | + Integer binarySum = binaryNumbers.reduce(Integer::sum).orElseThrow(StackOverflowError::new); |
| 30 | + |
| 31 | + boolean neoFound = list.stream().filter( s -> s.length() >= binarySum).allMatch(neoSearch); |
| 32 | + System.out.println(neoFound); |
| 33 | + } |
| 34 | +} |
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