Redesign BeanOverrideRegistry internals

spring-test/src/main/java/org/springframework/test/context/bean/override/BeanOverrideRegistry.java

@@ -27,9 +27,9 @@ import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.beans.factory.config.ConfigurableBeanFactory;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ReflectionUtils;
-import org.springframework.util.StringUtils;
 
 /**
  * An internal class used to track {@link BeanOverrideHandler}-related state after
@@ -110,14 +110,13 @@ class BeanOverrideRegistry {
 	void inject(Object target, BeanOverrideHandler handler) {
 		Field field = handler.getField();
 		Assert.notNull(field, () -> "BeanOverrideHandler must have a non-null field: " + handler);
-		String beanName = this.handlerToBeanNameMap.get(handler);
-		Assert.state(StringUtils.hasLength(beanName), () -> "No bean found for BeanOverrideHandler: " + handler);
-		inject(field, target, beanName);
+		Object bean = getBeanForHandler(handler, field.getType());
+		Assert.state(bean != null, () -> "No bean found for BeanOverrideHandler: " + handler);
+		inject(field, target, bean);
 	}
 
-	private void inject(Field field, Object target, String beanName) {
+	private void inject(Field field, Object target, Object bean) {
 		try {
-			Object bean = this.beanFactory.getBean(beanName, field.getType());
 			ReflectionUtils.makeAccessible(field);
 			ReflectionUtils.setField(field, target, bean);
 		}
@@ -126,4 +125,13 @@ class BeanOverrideRegistry {
 		}
 	}
 
+	@Nullable
+	private Object getBeanForHandler(BeanOverrideHandler handler, Class<?> requiredType) {
+		String beanName = this.handlerToBeanNameMap.get(handler);
+		if (beanName != null) {
+			return this.beanFactory.getBean(beanName, requiredType);
+		}
+		return null;
+	}
+
 }