org.killbill.commons.utils.concurrent.ThreadFactoryBuilder Maven / Gradle / Ivy
/*
* Copyright (C) 2010 The Guava Authors
* Copyright 2020-2022 Equinix, Inc
* Copyright 2014-2022 The Billing Project, LLC
*
* The Billing Project 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 org.killbill.commons.utils.concurrent;
import java.lang.Thread.UncaughtExceptionHandler;
import java.util.Locale;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicLong;
import javax.annotation.CheckForNull;
import org.killbill.commons.utils.Preconditions;
import static java.util.Objects.requireNonNull;
/**
* Verbatim copy of Guava's {@code ThreadFactoryBuilder}. Placed here instead of in {@code concurrent} module to avoid
* circular dependency.
*
* A ThreadFactory builder, providing any combination of these features:
*
*
* - whether threads should be marked as {@linkplain Thread#setDaemon daemon} threads
*
- a {@linkplain ThreadFactoryBuilder#setNameFormat naming format}
*
- a {@linkplain Thread#setPriority thread priority}
*
- an {@linkplain Thread#setUncaughtExceptionHandler uncaught exception handler}
*
- a {@linkplain ThreadFactory#newThread backing thread factory}
*
*
* If no backing thread factory is provided, a default backing thread factory is used as if by
* calling {@code setThreadFactory(}{@link Executors#defaultThreadFactory()}{@code )}.
*
* @author Kurt Alfred Kluever
* @since 4.0
*/
public final class ThreadFactoryBuilder {
@CheckForNull
private String nameFormat = null;
@CheckForNull private Boolean daemon = null;
@CheckForNull private Integer priority = null;
@CheckForNull private UncaughtExceptionHandler uncaughtExceptionHandler = null;
@CheckForNull private ThreadFactory backingThreadFactory = null;
/** Creates a new {@link ThreadFactory} builder. */
public ThreadFactoryBuilder() {}
/**
* Sets the naming format to use when naming threads ({@link Thread#setName}) which are created
* with this ThreadFactory.
*
* @param nameFormat a {@link String#format(String, Object...)}-compatible format String, to which
* a unique integer (0, 1, etc.) will be supplied as the single parameter. This integer will
* be unique to the built instance of the ThreadFactory and will be assigned sequentially. For
* example, {@code "rpc-pool-%d"} will generate thread names like {@code "rpc-pool-0"}, {@code
* "rpc-pool-1"}, {@code "rpc-pool-2"}, etc.
* @return this for the builder pattern
*/
public ThreadFactoryBuilder setNameFormat(final String nameFormat) {
this.nameFormat = nameFormat;
return this;
}
/**
* Sets daemon or not for new threads created with this ThreadFactory.
*
* @param daemon whether or not new Threads created with this ThreadFactory will be daemon threads
* @return this for the builder pattern
*/
public ThreadFactoryBuilder setDaemon(final boolean daemon) {
this.daemon = daemon;
return this;
}
/**
* Sets the priority for new threads created with this ThreadFactory.
*
* @param priority the priority for new Threads created with this ThreadFactory
* @return this for the builder pattern
*/
public ThreadFactoryBuilder setPriority(final int priority) {
// Thread#setPriority() already checks for validity. These error messages
// are nicer though and will fail-fast.
Preconditions.checkArgument(priority >= Thread.MIN_PRIORITY,
"Thread priority (%s) must be >= %s",
priority,
Thread.MIN_PRIORITY);
Preconditions.checkArgument(priority <= Thread.MAX_PRIORITY,
"Thread priority (%s) must be <= %s",
priority,
Thread.MAX_PRIORITY);
this.priority = priority;
return this;
}
/**
* Sets the {@link UncaughtExceptionHandler} for new threads created with this ThreadFactory.
*
* @param uncaughtExceptionHandler the uncaught exception handler for new Threads created with
* this ThreadFactory
* @return this for the builder pattern
*/
public ThreadFactoryBuilder setUncaughtExceptionHandler(final UncaughtExceptionHandler uncaughtExceptionHandler) {
this.uncaughtExceptionHandler = Preconditions.checkNotNull(uncaughtExceptionHandler);
return this;
}
/**
* Sets the backing {@link ThreadFactory} for new threads created with this ThreadFactory. Threads
* will be created by invoking #newThread(Runnable) on this backing {@link ThreadFactory}.
*
* @param backingThreadFactory the backing {@link ThreadFactory} which will be delegated to during
* thread creation.
* @return this for the builder pattern
*/
public ThreadFactoryBuilder setThreadFactory(final ThreadFactory backingThreadFactory) {
this.backingThreadFactory = Preconditions.checkNotNull(backingThreadFactory);
return this;
}
/**
* Returns a new thread factory using the options supplied during the building process. After
* building, it is still possible to change the options used to build the ThreadFactory and/or
* build again. State is not shared amongst built instances.
*
* @return the fully constructed {@link ThreadFactory}
*/
public ThreadFactory build() {
return doBuild(this);
}
// Split out so that the anonymous ThreadFactory can't contain a reference back to the builder.
// At least, I assume that's why. TODO(cpovirk): Check, and maybe add a test for this.
private static ThreadFactory doBuild(final ThreadFactoryBuilder builder) {
final String nameFormat = builder.nameFormat;
final Boolean daemon = builder.daemon;
final Integer priority = builder.priority;
final UncaughtExceptionHandler uncaughtExceptionHandler = builder.uncaughtExceptionHandler;
final ThreadFactory backingThreadFactory = builder.backingThreadFactory != null ?
builder.backingThreadFactory :
Executors.defaultThreadFactory();
final AtomicLong count = (nameFormat != null) ? new AtomicLong(0) : null;
return new ThreadFactory() {
@Override
public Thread newThread(final Runnable runnable) {
final Thread thread = backingThreadFactory.newThread(runnable);
if (nameFormat != null) {
// requireNonNull is safe because we create `count` if (and only if) we have a nameFormat.
thread.setName(format(nameFormat, requireNonNull(count).getAndIncrement()));
}
if (daemon != null) {
thread.setDaemon(daemon);
}
if (priority != null) {
thread.setPriority(priority);
}
if (uncaughtExceptionHandler != null) {
thread.setUncaughtExceptionHandler(uncaughtExceptionHandler);
}
return thread;
}
};
}
private static String format(final String format, final Object... args) {
return String.format(Locale.ROOT, format, args);
}
}