Fix bug in StaticListableBeanFactory.isSingleton()

Prior to this commit, StaticListableBeanFactory.isSingleton() returned
false for singleton beans unless they were created by a FactoryBean.

StaticListableBeanFactory.isSingleton() now properly returns true for
all beans not created by a FactoryBean.

Closes gh-25522

Author: sbrannen

spring-beans/src/main/java/org/springframework/beans/factory/support/StaticListableBeanFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -45,20 +45,22 @@
 
 /**
  * Static {@link org.springframework.beans.factory.BeanFactory} implementation
- * which allows to register existing singleton instances programmatically.
- * Does not have support for prototype beans or aliases.
+ * which allows one to register existing singleton instances programmatically.
  *
- * <p>Serves as example for a simple implementation of the
+ * <p>Does not have support for prototype beans or aliases.
+ *
+ * <p>Serves as an example for a simple implementation of the
  * {@link org.springframework.beans.factory.ListableBeanFactory} interface,
  * managing existing bean instances rather than creating new ones based on bean
  * definitions, and not implementing any extended SPI interfaces (such as
  * {@link org.springframework.beans.factory.config.ConfigurableBeanFactory}).
  *
- * <p>For a full-fledged factory based on bean definitions, have a look
- * at {@link DefaultListableBeanFactory}.
+ * <p>For a full-fledged factory based on bean definitions, have a look at
+ * {@link DefaultListableBeanFactory}.
  *
  * @author Rod Johnson
  * @author Juergen Hoeller
+ * @author Sam Brannen
  * @since 06.01.2003
  * @see DefaultListableBeanFactory
  */
@@ -83,7 +85,7 @@ public StaticListableBeanFactory() {
 	 * or {@link java.util.Collections#emptyMap()} for a dummy factory which
 	 * enforces operating against an empty set of beans.
 	 * @param beans a {@code Map} for holding this factory's beans, with the
-	 * bean name String as key and the corresponding singleton object as value
+	 * bean name as key and the corresponding singleton object as value
 	 * @since 4.3
 	 */
 	public StaticListableBeanFactory(Map<String, Object> beans) {
@@ -94,7 +96,7 @@ public StaticListableBeanFactory(Map<String, Object> beans) {
 
 	/**
 	 * Add a new singleton bean.
-	 * Will overwrite any existing instance for the given name.
+	 * <p>Will overwrite any existing instance for the given name.
 	 * @param name the name of the bean
 	 * @param bean the bean instance
 	 */
@@ -262,7 +264,10 @@ public boolean containsBean(String name) {
 	public boolean isSingleton(String name) throws NoSuchBeanDefinitionException {
 		Object bean = getBean(name);
 		// In case of FactoryBean, return singleton status of created object.
-		return (bean instanceof FactoryBean && ((FactoryBean<?>) bean).isSingleton());
+		if (bean instanceof FactoryBean) {
+			return ((FactoryBean<?>) bean).isSingleton();
+		}
+		return true;
 	}
 
 	@Override

spring-beans/src/test/java/org/springframework/beans/factory/BeanFactoryUtilsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -43,6 +43,7 @@
  * @author Rod Johnson
  * @author Juergen Hoeller
  * @author Chris Beams
+ * @author Sam Brannen
  * @since 04.07.2003
  */
 public class BeanFactoryUtilsTests {
@@ -319,4 +320,106 @@ public void testIntDependencies() {
 		assertTrue(Arrays.equals(new String[] { "buffer" }, deps));
 	}
 
+	@Test
+	public void isSingletonAndIsPrototypeWithStaticFactory() {
+		StaticListableBeanFactory lbf = new StaticListableBeanFactory();
+		TestBean bean = new TestBean();
+		DummyFactory fb1 = new DummyFactory();
+		DummyFactory fb2 = new DummyFactory();
+		fb2.setSingleton(false);
+		TestBeanSmartFactoryBean sfb1 = new TestBeanSmartFactoryBean(true, true);
+		TestBeanSmartFactoryBean sfb2 = new TestBeanSmartFactoryBean(true, false);
+		TestBeanSmartFactoryBean sfb3 = new TestBeanSmartFactoryBean(false, true);
+		TestBeanSmartFactoryBean sfb4 = new TestBeanSmartFactoryBean(false, false);
+		lbf.addBean("bean", bean);
+		lbf.addBean("fb1", fb1);
+		lbf.addBean("fb2", fb2);
+		lbf.addBean("sfb1", sfb1);
+		lbf.addBean("sfb2", sfb2);
+		lbf.addBean("sfb3", sfb3);
+		lbf.addBean("sfb4", sfb4);
+
+		Map<String, ?> beans = BeanFactoryUtils.beansOfTypeIncludingAncestors(lbf, ITestBean.class, true, true);
+		assertSame(bean, beans.get("bean"));
+		assertSame(fb1.getObject(), beans.get("fb1"));
+		assertTrue(beans.get("fb2") instanceof TestBean);
+		assertTrue(beans.get("sfb1") instanceof TestBean);
+		assertTrue(beans.get("sfb2") instanceof TestBean);
+		assertTrue(beans.get("sfb3") instanceof TestBean);
+		assertTrue(beans.get("sfb4") instanceof TestBean);
+
+		assertEquals(7, lbf.getBeanDefinitionCount());
+		assertTrue(lbf.getBean("bean") instanceof TestBean);
+		assertTrue(lbf.getBean("&fb1") instanceof FactoryBean);
+		assertTrue(lbf.getBean("&fb2") instanceof FactoryBean);
+		assertTrue(lbf.getBean("&sfb1") instanceof SmartFactoryBean);
+		assertTrue(lbf.getBean("&sfb2") instanceof SmartFactoryBean);
+		assertTrue(lbf.getBean("&sfb3") instanceof SmartFactoryBean);
+		assertTrue(lbf.getBean("&sfb4") instanceof SmartFactoryBean);
+
+		assertTrue(lbf.isSingleton("bean"));
+		assertTrue(lbf.isSingleton("fb1"));
+		assertTrue(lbf.isSingleton("fb2"));
+		assertTrue(lbf.isSingleton("sfb1"));
+		assertTrue(lbf.isSingleton("sfb2"));
+		assertTrue(lbf.isSingleton("sfb3"));
+		assertTrue(lbf.isSingleton("sfb4"));
+
+		assertTrue(lbf.isSingleton("&fb1"));
+		assertFalse(lbf.isSingleton("&fb2"));
+		assertTrue(lbf.isSingleton("&sfb1"));
+		assertTrue(lbf.isSingleton("&sfb2"));
+		assertFalse(lbf.isSingleton("&sfb3"));
+		assertFalse(lbf.isSingleton("&sfb4"));
+
+		assertFalse(lbf.isPrototype("bean"));
+		assertFalse(lbf.isPrototype("fb1"));
+		assertFalse(lbf.isPrototype("fb2"));
+		assertFalse(lbf.isPrototype("sfb1"));
+		assertFalse(lbf.isPrototype("sfb2"));
+		assertFalse(lbf.isPrototype("sfb3"));
+		assertFalse(lbf.isPrototype("sfb4"));
+
+		assertFalse(lbf.isPrototype("&fb1"));
+		assertTrue(lbf.isPrototype("&fb2"));
+		assertTrue(lbf.isPrototype("&sfb1"));
+		assertFalse(lbf.isPrototype("&sfb2"));
+		assertTrue(lbf.isPrototype("&sfb3"));
+		assertTrue(lbf.isPrototype("&sfb4"));
+	}
+
+
+	static class TestBeanSmartFactoryBean implements SmartFactoryBean<TestBean> {
+
+		private final TestBean testBean = new TestBean("enigma", 42);
+		private final boolean singleton;
+		private final boolean prototype;
+
+		TestBeanSmartFactoryBean(boolean singleton, boolean prototype) {
+			this.singleton = singleton;
+			this.prototype = prototype;
+		}
+
+		@Override
+		public boolean isSingleton() {
+			return this.singleton;
+		}
+
+		@Override
+		public boolean isPrototype() {
+			return this.prototype;
+		}
+
+		@Override
+		public Class<TestBean> getObjectType() {
+			return TestBean.class;
+		}
+
+		public TestBean getObject() throws Exception {
+			// We don't really care if the actual instance is a singleton or prototype
+			// for the tests that use this factory.
+			return this.testBean;
+		}
+	}
+
 }