ObjectProvider offers getIfAvailable/getIfUnique variants with default supplier

Issue: SPR-14980

spring-beans/src/main/java/org/springframework/beans/factory/ObjectProvider.java

@@ -16,6 +16,8 @@
 
 package org.springframework.beans.factory;
 
+import java.util.function.Supplier;
+
 import org.springframework.beans.BeansException;
 
 /**
@@ -48,6 +50,22 @@ public interface ObjectProvider<T> extends ObjectFactory<T> {
 	 */
 	T getIfAvailable() throws BeansException;
 
+	/**
+	 * Return an instance (possibly shared or independent) of the object
+	 * managed by this factory.
+	 * @param defaultSupplier a callback for supplying a default object
+	 * if none is present in the factory
+	 * @return an instance of the bean, or the supplied default object
+	 * if no such bean is available
+	 * @throws BeansException in case of creation errors
+	 * @since 5.0
+	 * @see #getIfAvailable()
+	 */
+	default T getIfAvailable(Supplier<T> defaultSupplier) throws BeansException {
+		T dependency = getIfAvailable();
+		return (dependency != null ? dependency : defaultSupplier.get());
+	}
+
 	/**
 	 * Return an instance (possibly shared or independent) of the object
 	 * managed by this factory.
@@ -58,4 +76,21 @@ public interface ObjectProvider<T> extends ObjectFactory<T> {
 	 */
 	T getIfUnique() throws BeansException;
 
+	/**
+	 * Return an instance (possibly shared or independent) of the object
+	 * managed by this factory.
+	 * @param defaultSupplier a callback for supplying a default object
+	 * if no unique candidate is present in the factory
+	 * @return an instance of the bean, or the supplied default object
+	 * if no such bean is available or if it is not unique in the factory
+	 * (i.e. multiple candidates found with none marked as primary)
+	 * @throws BeansException in case of creation errors
+	 * @since 5.0
+	 * @see #getIfUnique()
+	 */
+	default T getIfUnique(Supplier<T> defaultSupplier) throws BeansException {
+		T dependency = getIfUnique();
+		return (dependency != null ? dependency : defaultSupplier.get());
+	}
+
 }

spring-beans/src/test/java/org/springframework/beans/factory/annotation/AutowiredAnnotationBeanPostProcessorTests.java

@@ -1137,7 +1137,9 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 		assertEquals(bf.getBean("testBean"), bean.getTestBean());
 		assertEquals(bf.getBean("testBean", "myName"), bean.getTestBean("myName"));
 		assertEquals(bf.getBean("testBean"), bean.getOptionalTestBean());
+		assertEquals(bf.getBean("testBean"), bean.getOptionalTestBeanWithDefault());
 		assertEquals(bf.getBean("testBean"), bean.getUniqueTestBean());
+		assertEquals(bf.getBean("testBean"), bean.getUniqueTestBeanWithDefault());
 		bf.destroySingletons();
 	}
 
@@ -1153,7 +1155,9 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 		SmartObjectFactoryInjectionBean bean = (SmartObjectFactoryInjectionBean) bf.getBean("annotatedBean");
 		assertSame(bf.getBean("testBean"), bean.getTestBean());
 		assertSame(bf.getBean("testBean"), bean.getOptionalTestBean());
+		assertSame(bf.getBean("testBean"), bean.getOptionalTestBeanWithDefault());
 		assertSame(bf.getBean("testBean"), bean.getUniqueTestBean());
+		assertSame(bf.getBean("testBean"), bean.getUniqueTestBeanWithDefault());
 		bf.destroySingletons();
 	}
 
@@ -1174,6 +1178,8 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 			// expected
 		}
 		assertNull(bean.getOptionalTestBean());
+		assertEquals(new TestBean("default"), bean.getOptionalTestBeanWithDefault());
+		assertEquals(new TestBean("default"), bean.getUniqueTestBeanWithDefault());
 		assertNull(bean.getUniqueTestBean());
 		bf.destroySingletons();
 	}
@@ -2732,9 +2738,17 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 			return this.testBeanFactory.getIfAvailable();
 		}
 
+		public TestBean getOptionalTestBeanWithDefault() {
+			return this.testBeanFactory.getIfAvailable(() -> new TestBean("default"));
+		}
+
 		public TestBean getUniqueTestBean() {
 			return this.testBeanFactory.getIfUnique();
 		}
+
+		public TestBean getUniqueTestBeanWithDefault() {
+			return this.testBeanFactory.getIfUnique(() -> new TestBean("default"));
+		}
 	}