forked from fanruan/design
vito
7 years ago
4 changed files with 189 additions and 10 deletions
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/* |
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* Copyright (C) 2010 The Guava Authors |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except |
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* in compliance with the License. You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0
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* |
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* Unless required by applicable law or agreed to in writing, software distributed under the License |
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* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express |
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* or implied. See the License for the specific language governing permissions and limitations under |
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* the License. |
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*/ |
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package com.fr.design.utils.concurrent; |
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import java.lang.Thread.UncaughtExceptionHandler; |
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import java.util.Locale; |
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import java.util.concurrent.Executors; |
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import java.util.concurrent.ThreadFactory; |
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import java.util.concurrent.atomic.AtomicLong; |
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/** |
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* A ThreadFactory builder, providing any combination of these features: |
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* <ul> |
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* <li>whether threads should be marked as {@linkplain Thread#setDaemon daemon} threads |
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* <li>a {@linkplain ThreadFactoryBuilder#setNameFormat naming format} |
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* <li>a {@linkplain Thread#setPriority thread priority} |
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* <li>an {@linkplain Thread#setUncaughtExceptionHandler uncaught exception handler} |
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* <li>a {@linkplain ThreadFactory#newThread backing thread factory} |
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* </ul> |
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* <p>If no backing thread factory is provided, a default backing thread factory is used as if by |
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* calling {@code setThreadFactory(}{@link Executors#defaultThreadFactory()}{@code )}. |
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* |
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* @author Kurt Alfred Kluever |
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* @since 4.0 |
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*/ |
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public final class ThreadFactoryBuilder { |
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private String nameFormat = null; |
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private Boolean daemon = null; |
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private Integer priority = null; |
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private UncaughtExceptionHandler uncaughtExceptionHandler = null; |
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private ThreadFactory backingThreadFactory = null; |
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/** |
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* Creates a new {@link ThreadFactory} builder. |
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*/ |
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public ThreadFactoryBuilder() { |
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} |
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/** |
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* Sets the naming format to use when naming threads ({@link Thread#setName}) which are created |
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* with this ThreadFactory. |
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* |
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* @param nameFormat a {@link String#format(String, Object...)}-compatible format String, to which |
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* a unique integer (0, 1, etc.) will be supplied as the single parameter. This integer will |
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* be unique to the built instance of the ThreadFactory and will be assigned sequentially. For |
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* example, {@code "rpc-pool-%d"} will generate thread names like {@code "rpc-pool-0"}, |
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* {@code "rpc-pool-1"}, {@code "rpc-pool-2"}, etc. |
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* @return this for the builder pattern |
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*/ |
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public ThreadFactoryBuilder setNameFormat(String nameFormat) { |
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String unused = format(nameFormat, 0); // fail fast if the format is bad or null
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this.nameFormat = nameFormat; |
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return this; |
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} |
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/** |
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* Sets daemon or not for new threads created with this ThreadFactory. |
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* |
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* @param daemon whether or not new Threads created with this ThreadFactory will be daemon threads |
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* @return this for the builder pattern |
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*/ |
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public ThreadFactoryBuilder setDaemon(boolean daemon) { |
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this.daemon = daemon; |
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return this; |
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} |
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/** |
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* Sets the priority for new threads created with this ThreadFactory. |
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* |
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* @param priority the priority for new Threads created with this ThreadFactory |
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* @return this for the builder pattern |
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*/ |
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public ThreadFactoryBuilder setPriority(int priority) { |
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// Thread#setPriority() already checks for validity. These error messages
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// are nicer though and will fail-fast.
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if (priority < Thread.MIN_PRIORITY) { |
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throw new IllegalArgumentException(format("Thread priority (%s) must be >= %s", priority, Thread.MIN_PRIORITY)); |
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} |
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if (priority > Thread.MAX_PRIORITY) { |
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throw new IllegalArgumentException(format("Thread priority (%s) must be <= %s", priority, Thread.MAX_PRIORITY)); |
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} |
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this.priority = priority; |
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return this; |
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} |
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/** |
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* Sets the {@link UncaughtExceptionHandler} for new threads created with this ThreadFactory. |
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* |
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* @param uncaughtExceptionHandler the uncaught exception handler for new Threads created with |
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* this ThreadFactory |
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* @return this for the builder pattern |
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*/ |
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public ThreadFactoryBuilder setUncaughtExceptionHandler( |
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UncaughtExceptionHandler uncaughtExceptionHandler) { |
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if (uncaughtExceptionHandler == null) { |
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throw new NullPointerException(); |
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} |
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this.uncaughtExceptionHandler = uncaughtExceptionHandler; |
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return this; |
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} |
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/** |
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* Sets the backing {@link ThreadFactory} for new threads created with this ThreadFactory. Threads |
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* will be created by invoking #newThread(Runnable) on this backing {@link ThreadFactory}. |
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* |
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* @param backingThreadFactory the backing {@link ThreadFactory} which will be delegated to during |
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* thread creation. |
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* @return this for the builder pattern |
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*/ |
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public ThreadFactoryBuilder setThreadFactory(ThreadFactory backingThreadFactory) { |
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if (backingThreadFactory == null) { |
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throw new NullPointerException(); |
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} |
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this.backingThreadFactory = backingThreadFactory; |
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return this; |
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} |
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/** |
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* Returns a new thread factory using the options supplied during the building process. After |
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* building, it is still possible to change the options used to build the ThreadFactory and/or |
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* build again. State is not shared amongst built instances. |
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* |
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* @return the fully constructed {@link ThreadFactory} |
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*/ |
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public ThreadFactory build() { |
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return doBuild(this); |
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} |
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// Split out so that the anonymous ThreadFactory can't contain a reference back to the builder.
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// At least, I assume that's why. TODO(cpovirk): Check, and maybe add a test for this.
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private static ThreadFactory doBuild(ThreadFactoryBuilder builder) { |
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final String nameFormat = builder.nameFormat; |
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final Boolean daemon = builder.daemon; |
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final Integer priority = builder.priority; |
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final UncaughtExceptionHandler uncaughtExceptionHandler = builder.uncaughtExceptionHandler; |
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final ThreadFactory backingThreadFactory = |
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(builder.backingThreadFactory != null) |
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? builder.backingThreadFactory |
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: Executors.defaultThreadFactory(); |
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final AtomicLong count = (nameFormat != null) ? new AtomicLong(0) : null; |
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return new ThreadFactory() { |
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@Override |
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public Thread newThread(Runnable runnable) { |
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Thread thread = backingThreadFactory.newThread(runnable); |
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if (nameFormat != null) { |
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thread.setName(format(nameFormat, count.getAndIncrement())); |
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} |
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if (daemon != null) { |
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thread.setDaemon(daemon); |
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} |
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if (priority != null) { |
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thread.setPriority(priority); |
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} |
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if (uncaughtExceptionHandler != null) { |
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thread.setUncaughtExceptionHandler(uncaughtExceptionHandler); |
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} |
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return thread; |
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} |
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}; |
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} |
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private static String format(String format, Object... args) { |
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return String.format(Locale.ROOT, format, args); |
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} |
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} |
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