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Jenetics - Java Genetic Algorithm Library
/*
* Java Genetic Algorithm Library (jenetics-7.1.2).
* Copyright (c) 2007-2023 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 io.jenetics.internal.util;
import static java.lang.Math.ceil;
import static java.lang.Math.max;
import static java.util.Objects.requireNonNull;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;
import io.jenetics.util.Seq;
/**
* @author Franz Wilhelmstötter
* @version 3.8
* @since 2.0
*/
public abstract class Concurrency implements Executor, AutoCloseable {
public static final int CORES = Runtime.getRuntime().availableProcessors();
public static final Concurrency SERIAL_EXECUTOR = new SerialConcurrency();
public abstract void execute(final Seq runnables);
@Override
public abstract void close();
/**
* Return the underlying {@code Executor}, which is used for performing the
* actual task execution.
*
* @return the underlying {@code Executor} object
*/
public Executor getInnerExecutor() {
return this;
}
/**
* Return an new Concurrency object from the given executor.
*
* @param executor the underlying Executor
* @return a new Concurrency object
*/
public static Concurrency with(final Executor executor) {
if (executor instanceof ForkJoinPool e) {
return new ForkJoinPoolConcurrency(e);
} else if (executor instanceof ExecutorService e) {
return new ExecutorServiceConcurrency(e);
} else if (executor == SERIAL_EXECUTOR) {
return SERIAL_EXECUTOR;
} else {
return new ExecutorConcurrency(executor);
}
}
/**
* Return a new Concurrency object using the common ForkJoinPool.
*
* @return a new Concurrency object using the new ForkJoinPool
*/
public static Concurrency withCommonPool() {
return with(ForkJoinPool.commonPool());
}
/**
* This Concurrency uses a ForkJoinPool.
*/
private static final class ForkJoinPoolConcurrency extends Concurrency {
private final List> _tasks = new ArrayList<>();
private final ForkJoinPool _pool;
ForkJoinPoolConcurrency(final ForkJoinPool pool) {
_pool = requireNonNull(pool);
}
@Override
public void execute(final Runnable runnable) {
_tasks.add(_pool.submit(runnable));
}
@Override
public void execute(final Seq runnables) {
if (runnables.nonEmpty()) {
_tasks.add(_pool.submit(new RunnablesAction(runnables)));
}
}
@Override
public Executor getInnerExecutor() {
return _pool;
}
@Override
public void close() {
Concurrency.join(_tasks);
}
}
/**
* This Concurrency uses an ExecutorService.
*/
private static final class ExecutorServiceConcurrency extends Concurrency {
private final List> _futures = new ArrayList<>();
private final ExecutorService _service;
ExecutorServiceConcurrency(final ExecutorService service) {
_service = requireNonNull(service);
}
@Override
public void execute(final Runnable command) {
_futures.add(_service.submit(command));
}
@Override
public void execute(final Seq runnables) {
if (runnables.nonEmpty()) {
final int[] parts = partition(
runnables.size(),
max(
(CORES + 1)*2,
(int)ceil(runnables.size()/(double)Env.maxBatchSize)
)
);
for (int i = 0; i < parts.length - 1; ++i) {
execute(new RunnablesRunnable(runnables, parts[i], parts[i + 1]));
}
}
}
@Override
public Executor getInnerExecutor() {
return _service;
}
@Override
public void close() {
Concurrency.join(_futures);
}
}
private static void join(final Iterable> jobs) {
Future task = null;
Iterator> tasks = null;
try {
tasks = jobs.iterator();
while (tasks.hasNext()) {
task = tasks.next();
task.get();
}
} catch (ExecutionException e) {
Concurrency.cancel(task, tasks);
final String msg = e.getCause() != null
? e.getCause().getMessage()
: null;
throw (CancellationException)new CancellationException(msg)
.initCause(e.getCause());
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
Concurrency.cancel(task, tasks);
final String msg = e.getMessage();
throw (CancellationException)new CancellationException(msg)
.initCause(e);
}
}
private static void cancel(
final Future task,
final Iterator> tasks
) {
if (task != null) {
task.cancel(true);
}
if (tasks != null) {
tasks.forEachRemaining(t -> t.cancel(true));
}
}
/**
* This Concurrency uses an Executor.
*/
private static final class ExecutorConcurrency extends Concurrency {
private final List> _tasks = new ArrayList<>();
private final Executor _executor;
ExecutorConcurrency(final Executor executor) {
_executor = requireNonNull(executor);
}
@Override
public void execute(final Runnable command) {
final FutureTask task = new FutureTask<>(command, null);
_tasks.add(task);
_executor.execute(task);
}
@Override
public void execute(final Seq runnables) {
if (runnables.nonEmpty()) {
final int[] parts = partition(
runnables.size(),
max(
(CORES + 1)*2,
(int)ceil(runnables.size()/(double)Env.maxBatchSize)
)
);
for (int i = 0; i < parts.length - 1; ++i) {
execute(new RunnablesRunnable(runnables, parts[i], parts[i + 1]));
}
}
}
@Override
public void close() {
Concurrency.join(_tasks);
}
}
/**
* This Concurrency executes the runnables within the main thread.
*/
private static final class SerialConcurrency extends Concurrency {
@Override
public void execute(final Runnable command) {
command.run();
}
@Override
public void execute(final Seq runnables) {
runnables.forEach(Runnable::run);
}
@Override
public void close() {
}
}
/**
* Return a array with the indexes of the partitions of an array with the
* given size. The length of the returned array is {@code min(size, prts) + 1}.
*
* Some examples:
*
* partition(10, 3): [0, 3, 6, 10]
* partition(15, 6): [0, 2, 4, 6, 9, 12, 15]
* partition(5, 10): [0, 1, 2, 3, 4, 5]
*
*
* The following examples prints the start index (inclusive) and the end
* index (exclusive) of the {@code partition(15, 6)}.
* {@code
* int[] parts = partition(15, 6);
* for (int i = 0; i < parts.length - 1; ++i) {
* System.out.println(i + ": " + parts[i] + "\t" + parts[i + 1]);
* }
* }
*
* 0: 0 2
* 1: 2 4
* 2: 4 6
* 3: 6 9
* 4: 9 12
* 5: 12 15
*
*
* This example shows how this can be used in an concurrent environment:
* {@code
* try (final Concurrency c = Concurrency.start()) {
* final int[] parts = arrays.partition(population.size(), _maxThreads);
*
* for (int i = 0; i < parts.length - 1; ++i) {
* final int part = i;
* c.execute(new Runnable() { @Override public void run() {
* for (int j = parts[part + 1]; --j <= parts[part];) {
* population.get(j).evaluate();
* }
* }});
* }
* }
* }
*
* @param size the size of the array to partition.
* @param parts the number of parts the (virtual) array should be partitioned.
* @return the partition array with the length of {@code min(size, parts) + 1}.
* @throws IllegalArgumentException if {@code size} or {@code p} is less than one.
*/
private static int[] partition(final int size, final int parts) {
if (size < 1) {
throw new IllegalArgumentException(
"Size must greater than zero: " + size
);
}
if (parts < 1) {
throw new IllegalArgumentException(
"Number of partitions must greater than zero: " + parts
);
}
final int pts = Math.min(size, parts);
final int[] partition = new int[pts + 1];
final int bulk = size/pts;
final int rest = size%pts;
assert (bulk*pts + rest) == size;
for (int i = 0, n = pts - rest; i < n; ++i) {
partition[i] = i*bulk;
}
for (int i = 0, n = rest + 1; i < n; ++i) {
partition[pts - rest + i] = (pts - rest)*bulk + i*(bulk + 1);
}
return partition;
}
@SuppressWarnings("removal")
private static final class Env {
private static final int maxBatchSize = max(
java.security.AccessController.doPrivileged(
(java.security.PrivilegedAction)() -> Integer.getInteger(
"io.jenetics.concurrency.maxBatchSize",
Integer.MAX_VALUE
)),
1
);
}
}