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Jenetics - Java Genetic Algorithm Library

There is a newer version: 3.6.0

/*
 * Java Genetic Algorithm Library (jenetics-3.1.0).
 * Copyright (c) 2007-2015 Franz Wilhelmstötter
 *
 * Licensed 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.
 *
 * Author:
 *    Franz Wilhelmstötter ([email protected])
 */
package org.jenetics.engine;

import static java.util.Objects.requireNonNull;

import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;

import org.jenetics.Gene;

/**
 * @author Franz Wilhelmstötter
 * @since 3.0
 * @version 3.0
 */
final class EvolutionStreamImpl<
	G extends Gene,
	C extends Comparable
>
	extends StreamProxy>
	implements EvolutionStream
{

	private final Supplier> _start;
	private final Function, EvolutionResult> _evolution;
	private final Predicate> _proceed;

	private EvolutionStreamImpl(
		final Supplier> start,
		final Function, EvolutionResult> evolution,
		final Stream> stream,
		final Predicate> proceed
	) {
		super(stream);
		_evolution = requireNonNull(evolution);
		_start = requireNonNull(start);
		_proceed = requireNonNull(proceed);
	}

	EvolutionStreamImpl(
		final Supplier> start,
		final Function, EvolutionResult> evolution
	) {
		this(
			start, evolution,
			StreamSupport.stream(
				new EvolutionSpliterator<>(start, evolution, TRUE()),
				false
			),
			TRUE()
		);
	}

	@Override
	public EvolutionStream
	limit(final Predicate> proceed) {
		final Predicate> prcd =
			_proceed == TRUE ? proceed :
				r -> proceed.test(r) & _proceed.test(r);

		return new EvolutionStreamImpl<>(
			_start,
			_evolution,
			StreamSupport.stream(
				new EvolutionSpliterator<>(_start, _evolution, prcd),
				false
			),
			prcd
		);
	}

	private static final Predicate TRUE = a -> true;

	@SuppressWarnings("unchecked")
	private static  Predicate TRUE() {
		return (Predicate)TRUE;
	}

}