ObjectProvider offers ifAvailable/ifUnique variants with Consumer

Issue: SPR-16001

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.beans.factory;
 
+import java.util.function.Consumer;
 import java.util.function.Supplier;
 
 import org.springframework.beans.BeansException;
@@ -68,6 +69,22 @@ public interface ObjectProvider<T> extends ObjectFactory<T> {
 		return (dependency != null ? dependency : defaultSupplier.get());
 	}
 
+	/**
+	 * Consume an instance (possibly shared or independent) of the object
+	 * managed by this factory, if available.
+	 * @param dependencyConsumer a callback for processing the target object
+	 * if available (not called otherwise)
+	 * @throws BeansException in case of creation errors
+	 * @since 5.0
+	 * @see #getIfAvailable()
+	 */
+	default void ifAvailable(Consumer<T> dependencyConsumer) throws BeansException {
+		T dependency = getIfAvailable();
+		if (dependency != null) {
+			dependencyConsumer.accept(dependency);
+		}
+	}
+
 	/**
 	 * Return an instance (possibly shared or independent) of the object
 	 * managed by this factory.
@@ -96,4 +113,20 @@ public interface ObjectProvider<T> extends ObjectFactory<T> {
 		return (dependency != null ? dependency : defaultSupplier.get());
 	}
 
+	/**
+	 * Consume an instance (possibly shared or independent) of the object
+	 * managed by this factory, if unique.
+	 * @param dependencyConsumer a callback for processing the target object
+	 * if unique (not called otherwise)
+	 * @throws BeansException in case of creation errors
+	 * @since 5.0
+	 * @see #getIfAvailable()
+	 */
+	default void ifUnique(Consumer<T> dependencyConsumer) throws BeansException {
+		T dependency = getIfUnique();
+		if (dependency != null) {
+			dependencyConsumer.accept(dependency);
+		}
+	}
+
 }

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

@@ -1297,8 +1297,10 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 		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.consumeOptionalTestBean());
 		assertEquals(bf.getBean("testBean"), bean.getUniqueTestBean());
 		assertEquals(bf.getBean("testBean"), bean.getUniqueTestBeanWithDefault());
+		assertEquals(bf.getBean("testBean"), bean.consumeUniqueTestBean());
 		bf.destroySingletons();
 	}
 
@@ -1315,8 +1317,10 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 		assertSame(bf.getBean("testBean"), bean.getTestBean());
 		assertSame(bf.getBean("testBean"), bean.getOptionalTestBean());
 		assertSame(bf.getBean("testBean"), bean.getOptionalTestBeanWithDefault());
+		assertEquals(bf.getBean("testBean"), bean.consumeOptionalTestBean());
 		assertSame(bf.getBean("testBean"), bean.getUniqueTestBean());
 		assertSame(bf.getBean("testBean"), bean.getUniqueTestBeanWithDefault());
+		assertEquals(bf.getBean("testBean"), bean.consumeUniqueTestBean());
 		bf.destroySingletons();
 	}
 
@@ -1337,9 +1341,11 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 			// expected
 		}
 		assertNull(bean.getOptionalTestBean());
+		assertNull(bean.consumeOptionalTestBean());
 		assertEquals(new TestBean("default"), bean.getOptionalTestBeanWithDefault());
 		assertEquals(new TestBean("default"), bean.getUniqueTestBeanWithDefault());
 		assertNull(bean.getUniqueTestBean());
+		assertNull(bean.consumeUniqueTestBean());
 		bf.destroySingletons();
 	}
 
@@ -1368,7 +1374,15 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 		catch (NoUniqueBeanDefinitionException ex) {
 			// expected
 		}
+		try {
+			bean.consumeOptionalTestBean();
+			fail("Should have thrown NoUniqueBeanDefinitionException");
+		}
+		catch (NoUniqueBeanDefinitionException ex) {
+			// expected
+		}
 		assertNull(bean.getUniqueTestBean());
+		assertNull(bean.consumeUniqueTestBean());
 		bf.destroySingletons();
 	}
 
@@ -1389,7 +1403,9 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 		SmartObjectFactoryInjectionBean bean = (SmartObjectFactoryInjectionBean) bf.getBean("annotatedBean");
 		assertSame(bf.getBean("testBean1"), bean.getTestBean());
 		assertSame(bf.getBean("testBean1"), bean.getOptionalTestBean());
+		assertSame(bf.getBean("testBean1"), bean.consumeOptionalTestBean());
 		assertSame(bf.getBean("testBean1"), bean.getUniqueTestBean());
+		assertSame(bf.getBean("testBean1"), bean.consumeUniqueTestBean());
 		assertFalse(bf.containsSingleton("testBean2"));
 		bf.destroySingletons();
 	}
@@ -3020,6 +3036,8 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 		@Autowired
 		private ObjectProvider<TestBean> testBeanFactory;
 
+		private TestBean consumedTestBean;
+
 		public TestBean getTestBean() {
 			return this.testBeanFactory.getObject();
 		}
@@ -3036,6 +3054,11 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 			return this.testBeanFactory.getIfAvailable(() -> new TestBean("default"));
 		}
 
+		public TestBean consumeOptionalTestBean() {
+			this.testBeanFactory.ifAvailable(tb -> consumedTestBean = tb);
+			return consumedTestBean;
+		}
+
 		public TestBean getUniqueTestBean() {
 			return this.testBeanFactory.getIfUnique();
 		}
@@ -3043,6 +3066,11 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 		public TestBean getUniqueTestBeanWithDefault() {
 			return this.testBeanFactory.getIfUnique(() -> new TestBean("default"));
 		}
+
+		public TestBean consumeUniqueTestBean() {
+			this.testBeanFactory.ifUnique(tb -> consumedTestBean = tb);
+			return consumedTestBean;
+		}
 	}