| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package accord.utils; |
| |
| import java.util.function.BiFunction; |
| import java.util.function.Function; |
| import java.util.function.IntPredicate; |
| import java.util.function.IntSupplier; |
| import java.util.function.IntUnaryOperator; |
| import java.util.function.LongPredicate; |
| import java.util.function.LongSupplier; |
| import java.util.function.LongUnaryOperator; |
| import java.util.function.Predicate; |
| import java.util.function.Supplier; |
| import java.util.function.ToIntFunction; |
| import java.util.function.ToLongFunction; |
| import java.util.stream.IntStream; |
| import java.util.stream.LongStream; |
| import java.util.stream.Stream; |
| |
| public interface Gen<A> { |
| /** |
| * For cases where method handles isn't able to detect the proper type, this method acts as a cast |
| * to inform the compiler of the desired type. |
| */ |
| static <A> Gen<A> of(Gen<A> fn) |
| { |
| return fn; |
| } |
| |
| A next(RandomSource random); |
| |
| default <B> Gen<B> map(Function<? super A, ? extends B> fn) |
| { |
| return r -> fn.apply(this.next(r)); |
| } |
| |
| default <B> Gen<B> map(BiFunction<RandomSource, ? super A, ? extends B> fn) |
| { |
| return r -> fn.apply(r, this.next(r)); |
| } |
| |
| default IntGen mapToInt(ToIntFunction<A> fn) |
| { |
| return r -> fn.applyAsInt(next(r)); |
| } |
| |
| default LongGen mapToLong(ToLongFunction<A> fn) |
| { |
| return r -> fn.applyAsLong(next(r)); |
| } |
| |
| default <B> Gen<B> flatMap(Function<? super A, Gen<? extends B>> mapper) |
| { |
| return rs -> mapper.apply(this.next(rs)).next(rs); |
| } |
| |
| default <B> Gen<B> flatMap(BiFunction<RandomSource, ? super A, Gen<? extends B>> mapper) |
| { |
| return rs -> mapper.apply(rs, this.next(rs)).next(rs); |
| } |
| |
| default Gen<A> filter(Predicate<A> fn) |
| { |
| Gen<A> self = this; |
| return r -> { |
| A value; |
| do { |
| value = self.next(r); |
| } |
| while (!fn.test(value)); |
| return value; |
| }; |
| } |
| |
| default Supplier<A> asSupplier(RandomSource rs) |
| { |
| return () -> next(rs); |
| } |
| |
| default Stream<A> asStream(RandomSource rs) |
| { |
| return Stream.generate(() -> next(rs)); |
| } |
| |
| interface IntGen extends Gen<Integer> |
| { |
| int nextInt(RandomSource random); |
| |
| @Override |
| default Integer next(RandomSource random) |
| { |
| return nextInt(random); |
| } |
| |
| default IntGen mapAsInt(IntUnaryOperator fn) |
| { |
| return r -> fn.applyAsInt(nextInt(r)); |
| } |
| |
| default Gen.IntGen filterAsInt(IntPredicate fn) |
| { |
| return rs -> { |
| int value; |
| do |
| { |
| value = nextInt(rs); |
| } |
| while (!fn.test(value)); |
| return value; |
| }; |
| } |
| |
| @Override |
| default Gen.IntGen filter(Predicate<Integer> fn) |
| { |
| return filterAsInt(i -> fn.test(i)); |
| } |
| |
| default IntSupplier asIntSupplier(RandomSource rs) |
| { |
| return () -> nextInt(rs); |
| } |
| |
| default IntStream asIntStream(RandomSource rs) |
| { |
| return IntStream.generate(() -> nextInt(rs)); |
| } |
| } |
| |
| interface LongGen extends Gen<Long> |
| { |
| long nextLong(RandomSource random); |
| |
| @Override |
| default Long next(RandomSource random) |
| { |
| return nextLong(random); |
| } |
| |
| default LongGen mapAsLong(LongUnaryOperator fn) |
| { |
| return r -> fn.applyAsLong(nextLong(r)); |
| } |
| |
| default Gen.LongGen filterAsLong(LongPredicate fn) |
| { |
| return rs -> { |
| long value; |
| do |
| { |
| value = nextLong(rs); |
| } |
| while (!fn.test(value)); |
| return value; |
| }; |
| } |
| |
| @Override |
| default Gen.LongGen filter(Predicate<Long> fn) |
| { |
| return filterAsLong(i -> fn.test(i)); |
| } |
| |
| default LongSupplier asLongSupplier(RandomSource rs) |
| { |
| return () -> nextLong(rs); |
| } |
| |
| default LongStream asLongStream(RandomSource rs) |
| { |
| return LongStream.generate(() -> nextLong(rs)); |
| } |
| } |
| } |