Polish "Expose prestartAllCoreThreads on ExecutorService"

See gh-1246

spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolExecutorFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -73,14 +73,14 @@ public class ThreadPoolExecutorFactoryBean extends ExecutorConfigurationSupport
 
 	private int keepAliveSeconds = 60;
 
-	private int queueCapacity = Integer.MAX_VALUE;
-
 	private boolean allowCoreThreadTimeOut = false;
 
-	private boolean exposeUnconfigurableExecutor = false;
-
 	private boolean prestartAllCoreThreads = false;
 
+	private int queueCapacity = Integer.MAX_VALUE;
+
+	private boolean exposeUnconfigurableExecutor = false;
+
 	@Nullable
 	private ExecutorService exposedExecutor;
 
@@ -120,6 +120,16 @@ public void setAllowCoreThreadTimeOut(boolean allowCoreThreadTimeOut) {
 		this.allowCoreThreadTimeOut = allowCoreThreadTimeOut;
 	}
 
+	/**
+	 * Specify whether to start all core threads, causing them to idly wait for work.
+	 * <p>Default is "false".
+	 * @since 5.3.14
+	 * @see java.util.concurrent.ThreadPoolExecutor#prestartAllCoreThreads
+	 */
+	public void setPrestartAllCoreThreads(boolean prestartAllCoreThreads) {
+		this.prestartAllCoreThreads = prestartAllCoreThreads;
+	}
+
 	/**
 	 * Set the capacity for the ThreadPoolExecutor's BlockingQueue.
 	 * Default is {@code Integer.MAX_VALUE}.
@@ -132,17 +142,6 @@ public void setQueueCapacity(int queueCapacity) {
 		this.queueCapacity = queueCapacity;
 	}
 
-	/**
-	 * Specify whether this FactoryBean should prestart all threads
-	 * for the created executor.
-	 * <p>Default is "false".
-	 * Switch this flag to "true" to prestart the threads allocated for the current executor
-	 * @see java.util.concurrent.ThreadPoolExecutor#prestartAllCoreThreads
-	 */
-	public void setPrestartAllCoreThreads(boolean prestartAllCoreThreads) {
-		this.prestartAllCoreThreads = prestartAllCoreThreads;
-	}
-
 	/**
 	 * Specify whether this FactoryBean should expose an unconfigurable
 	 * decorator for the created executor.
@@ -166,7 +165,6 @@ protected ExecutorService initializeExecutor(
 		if (this.allowCoreThreadTimeOut) {
 			executor.allowCoreThreadTimeOut(true);
 		}
-
 		if (this.prestartAllCoreThreads) {
 			executor.prestartAllCoreThreads();
 		}

spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskExecutor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -94,6 +94,8 @@ public class ThreadPoolTaskExecutor extends ExecutorConfigurationSupport
 
 	private boolean allowCoreThreadTimeOut = false;
 
+	private boolean prestartAllCoreThreads = false;
+
 	@Nullable
 	private TaskDecorator taskDecorator;
 
@@ -197,6 +199,16 @@ public void setAllowCoreThreadTimeOut(boolean allowCoreThreadTimeOut) {
 		this.allowCoreThreadTimeOut = allowCoreThreadTimeOut;
 	}
 
+	/**
+	 * Specify whether to start all core threads, causing them to idly wait for work.
+	 * <p>Default is "false".
+	 * @since 5.3.14
+	 * @see java.util.concurrent.ThreadPoolExecutor#prestartAllCoreThreads
+	 */
+	public void setPrestartAllCoreThreads(boolean prestartAllCoreThreads) {
+		this.prestartAllCoreThreads = prestartAllCoreThreads;
+	}
+
 	/**
 	 * Specify a custom {@link TaskDecorator} to be applied to any {@link Runnable}
 	 * about to be executed.
@@ -256,6 +268,9 @@ public void execute(Runnable command) {
 		if (this.allowCoreThreadTimeOut) {
 			executor.allowCoreThreadTimeOut(true);
 		}
+		if (this.prestartAllCoreThreads) {
+			executor.prestartAllCoreThreads();
+		}
 
 		this.threadPoolExecutor = executor;
 		return executor;

spring-context/src/test/java/org/springframework/scheduling/concurrent/ThreadPoolExecutorFactoryBeanTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,18 +25,20 @@
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.context.ApplicationContext;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.support.GenericApplicationContext;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
 
 /**
+ * Tests for {@link ThreadPoolExecutorFactoryBean}.
+ *
  * @author Juergen Hoeller
  */
 class ThreadPoolExecutorFactoryBeanTests {
@@ -53,19 +55,25 @@ void defaultExecutor() throws Exception {
 	}
 
 	@Test
-	public void executorWithPreStartedThreads() throws Exception {
-		ConfigurableApplicationContext context = new AnnotationConfigApplicationContext(ExecutorConfigWithPreStartedThreads.class);
-		ThreadPoolExecutor executor = context.getBean("childExecutor", ThreadPoolExecutor.class);
-
-		verify(executor).prestartAllCoreThreads();
+	void executorWithDefaultSettingsDoesNotPrestartAllCoreThreads() {
+		GenericApplicationContext context = new GenericApplicationContext();
+		context.registerBean("taskExecutor", ThreadPoolExecutorFactoryBean.class, TestThreadPoolExecutorFactoryBean::new);
+		context.refresh();
+		ThreadPoolExecutor threadPoolExecutor = context.getBean(ThreadPoolExecutor.class);
+		verify(threadPoolExecutor, never()).prestartAllCoreThreads();
 	}
 
 	@Test
-	public void executorWithNoPreStartedThreads() throws Exception {
-		ConfigurableApplicationContext context = new AnnotationConfigApplicationContext(ExecutorConfigWithNoPreStartedThreads.class);
-		ThreadPoolExecutor executor = context.getBean("childExecutor", ThreadPoolExecutor.class);
-
-		verify(executor, never()).prestartAllCoreThreads();
+	void executorWithPrestartAllCoreThreads() {
+		GenericApplicationContext context = new GenericApplicationContext();
+		context.registerBean("taskExecutor", ThreadPoolExecutorFactoryBean.class, () -> {
+			TestThreadPoolExecutorFactoryBean factoryBean = new TestThreadPoolExecutorFactoryBean();
+			factoryBean.setPrestartAllCoreThreads(true);
+			return factoryBean;
+		});
+		context.refresh();
+		ThreadPoolExecutor threadPoolExecutor = context.getBean(ThreadPoolExecutor.class);
+		verify(threadPoolExecutor).prestartAllCoreThreads();
 	}
 
 	@Configuration
@@ -78,37 +86,8 @@ ThreadPoolExecutorFactoryBean executor() {
 
 	}
 
-	@Configuration
-	public static class ExecutorConfigWithPreStartedThreads {
-
-		@Bean
-		public ThreadPoolExecutorFactoryBean executorChildFactory() {
-			ThreadPoolExecutorFactoryBeanMockingChild threadPoolExecutorFactoryBeanMockingChild = new ThreadPoolExecutorFactoryBeanMockingChild();
-			threadPoolExecutorFactoryBeanMockingChild.setPrestartAllCoreThreads(true);
-			return threadPoolExecutorFactoryBeanMockingChild;
-		}
-
-		@Bean
-		public ExecutorService childExecutor() {
-			return executorChildFactory().getObject();
-		}
-	}
+	private static class TestThreadPoolExecutorFactoryBean extends ThreadPoolExecutorFactoryBean {
 
-	@Configuration
-	public static class ExecutorConfigWithNoPreStartedThreads {
-
-		@Bean
-		public ThreadPoolExecutorFactoryBean executorChildFactory() {
-			return new ThreadPoolExecutorFactoryBeanMockingChild();
-		}
-
-		@Bean
-		public ExecutorService childExecutor() {
-			return executorChildFactory().getObject();
-		}
-	}
-
-	private static class ThreadPoolExecutorFactoryBeanMockingChild extends ThreadPoolExecutorFactoryBean {
 		@Override
 		protected ThreadPoolExecutor createExecutor(
 				int corePoolSize, int maxPoolSize, int keepAliveSeconds, BlockingQueue<Runnable> queue,
@@ -118,5 +97,4 @@ protected ThreadPoolExecutor createExecutor(
 		}
 	}
 
-
 }