序本文主要研究一下Elasticsearch的FixedExecutorBuilder
FixedExecutorBuilderelasticsearch-7.0.1/server/src/main/java/org/elasticsearch/threadpool/FixedExecutorBuilder.java
public final class FixedExecutorBuilder extends ExecutorBuilder<FixedExecutorBuilder.FixedExecutorSettings> { private final Setting<Integer> sizeSetting; private final Setting<Integer> queueSizeSetting; /** * Construct a fixed executor builder; the settings will have the key prefix "thread_pool." followed by the executor name. * * @param settings the node-level settings * @param name the name of the executor * @param size the fixed number of threads * @param queueSize the size of the backing queue, -1 for unbounded */ FixedExecutorBuilder(final Settings settings, final String name, final int size, final int queueSize) { this(settings, name, size, queueSize, "thread_pool." + name); } /** * Construct a fixed executor builder. * * @param settings the node-level settings * @param name the name of the executor * @param size the fixed number of threads * @param queueSize the size of the backing queue, -1 for unbounded * @param prefix the prefix for the settings keys */ public FixedExecutorBuilder(final Settings settings, final String name, final int size, final int queueSize, final String prefix) { super(name); final String sizeKey = settingsKey(prefix, "size"); this.sizeSetting = new Setting<>( sizeKey, s -> Integer.toString(size), s -> Setting.parseInt(s, 1, applyHardSizeLimit(settings, name), sizeKey), Setting.Property.NodeScope); final String queueSizeKey = settingsKey(prefix, "queue_size"); this.queueSizeSetting = Setting.intSetting(queueSizeKey, queueSize, Setting.Property.NodeScope); } @Override public List<Setting<?>> getRegisteredSettings() { return Arrays.asList(sizeSetting, queueSizeSetting); } @Override FixedExecutorSettings getSettings(Settings settings) { final String nodeName = Node.NODE_NAME_SETTING.get(settings); final int size = sizeSetting.get(settings); final int queueSize = queueSizeSetting.get(settings); return new FixedExecutorSettings(nodeName, size, queueSize); } @Override ThreadPool.ExecutorHolder build(final FixedExecutorSettings settings, final ThreadContext threadContext) { int size = settings.size; int queueSize = settings.queueSize; final ThreadFactory threadFactory = EsExecutors.daemonThreadFactory(EsExecutors.threadName(settings.nodeName, name())); final ExecutorService executor = EsExecutors.newFixed(settings.nodeName + "/" + name(), size, queueSize, threadFactory, threadContext); final ThreadPool.Info info = new ThreadPool.Info(name(), ThreadPool.ThreadPoolType.FIXED, size, size, null, queueSize < 0 ? null : new SizeValue(queueSize)); return new ThreadPool.ExecutorHolder(executor, info); } @Override String formatInfo(ThreadPool.Info info) { return String.format( Locale.ROOT, "name [%s], size [%d], queue size [%s]", info.getName(), info.getMax(), info.getQueueSize() == null ? "unbounded" : info.getQueueSize()); } static class FixedExecutorSettings extends ExecutorBuilder.ExecutorSettings { private final int size; private final int queueSize; FixedExecutorSettings(final String nodeName, final int size, final int queueSize) { super(nodeName); this.size = size; this.queueSize = queueSize; } }}FixedExecutorBuilder继承了ExecutorBuilder，其ExecutorSettings类型为FixedExecutorSettings，它定义size及queueSize两个属性；其build方法使用EsExecutors.newFixed创建ExecutorService，同时还创建了ThreadPool.Info，最后返回包含二者的ThreadPool.ExecutorHolderEsExecutors.newFixedelasticsearch-7.0.1/server/src/main/java/org/elasticsearch/common/util/concurrent/EsExecutors.java
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