avoid hard-coded dependency on backport-concurrent (SPR-6161)

Author: jhoeller

org.springframework.context/src/main/java/org/springframework/scheduling/config/ExecutorBeanDefinitionParser.java

@@ -16,30 +16,32 @@
 
 package org.springframework.scheduling.config;
 
-import java.util.concurrent.ThreadPoolExecutor;
-
 import org.w3c.dom.Element;
 
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
+import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
 import org.springframework.core.JdkVersion;
 import org.springframework.util.StringUtils;
 
 /**
  * Parser for the 'executor' element of the 'task' namespace.
- * 
+ *
  * @author Mark Fisher
+ * @author Juergen Hoeller
  * @since 3.0
  */
 public class ExecutorBeanDefinitionParser extends AbstractSingleBeanDefinitionParser {
 
 	@Override
 	protected String getBeanClassName(Element element) {
-		if (this.shouldUseBackport(element)) {
+		if (shouldUseBackport(element)) {
 			return "org.springframework.scheduling.backportconcurrent.ThreadPoolTaskExecutor";
 		}
-		return "org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor";
+		else {
+			return "org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor";
+		}
 	}
 
 	@Override
@@ -52,7 +54,7 @@ protected void doParse(Element element, ParserContext parserContext, BeanDefinit
 		if (StringUtils.hasText(queueCapacity)) {
 			builder.addPropertyValue("queueCapacity", queueCapacity);
 		}
-		this.configureRejectionPolicy(element, builder);
+		configureRejectionPolicy(element, builder);
 		String poolSize = element.getAttribute("pool-size");
 		if (!StringUtils.hasText(poolSize)) {
 			return;
@@ -104,43 +106,33 @@ private void configureRejectionPolicy(Element element, BeanDefinitionBuilder bui
 		if (!StringUtils.hasText(rejectionPolicy)) {
 			return;
 		}
-		Object handler = null;		
-		boolean createBackportHandler = this.shouldUseBackport(element);
+		String prefix = "java.util.concurrent.ThreadPoolExecutor.";
+		if (builder.getRawBeanDefinition().getBeanClassName().contains("backport")) {
+			prefix = "edu.emory.mathcs.backport." + prefix;
+		}
+		String policyClassName;
 		if (rejectionPolicy.equals("ABORT")) {
-			if (createBackportHandler) {
-				handler = new edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.AbortPolicy();
-			}
-			else {
-				handler = new ThreadPoolExecutor.AbortPolicy();
-			}
+			policyClassName = prefix + "AbortPolicy";
 		}
-		if (rejectionPolicy.equals("CALLER_RUNS")) {
-			if (createBackportHandler) {
-				handler = new edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.CallerRunsPolicy();
-			}
-			else {
-				handler = new ThreadPoolExecutor.CallerRunsPolicy();
-			}
+		else if (rejectionPolicy.equals("CALLER_RUNS")) {
+			policyClassName = prefix + "CallerRunsPolicy";
 		}
-		if (rejectionPolicy.equals("DISCARD")) {
-			if (createBackportHandler) {
-				handler = new edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.DiscardPolicy();
-			}
-			handler = new ThreadPoolExecutor.DiscardPolicy();
+		else if (rejectionPolicy.equals("DISCARD")) {
+			policyClassName = prefix + "DiscardPolicy";
 		}
-		if (rejectionPolicy.equals("DISCARD_OLDEST")) {
-			if (createBackportHandler) {
-				handler = new edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.DiscardOldestPolicy();
-			}
-			handler = new ThreadPoolExecutor.DiscardOldestPolicy();
+		else if (rejectionPolicy.equals("DISCARD_OLDEST")) {
+			policyClassName = prefix + "DiscardOldestPolicy";
+		}
+		else {
+			policyClassName = rejectionPolicy;
 		}
-		builder.addPropertyValue("rejectedExecutionHandler", handler);
+		builder.addPropertyValue("rejectedExecutionHandler", new RootBeanDefinition(policyClassName));
 	}
 
 	private boolean shouldUseBackport(Element element) {
 		String poolSize = element.getAttribute("pool-size");
-		return StringUtils.hasText(poolSize) && poolSize.startsWith("0")
-				&& JdkVersion.getMajorJavaVersion() < JdkVersion.JAVA_16;
+		return (StringUtils.hasText(poolSize) && poolSize.startsWith("0") &&
+				JdkVersion.getMajorJavaVersion() < JdkVersion.JAVA_16);
 	}
 
 }