Support for @Order at the bean declaration level

This commit introduces OrderProvider and OrderProviderComparator, two
interfaces designed to externalize how a collection of element is sorted
according to their order value.

FactoryAwareOrderProvider is an OrderProvider implementation that knows
about the objects to order and the corresponding BeanFactory instance.
This allows to retrieve additional metadata about the actual instances
to sort, such as its factory method.

A @Bean method can now holds an additional @Order to define the order
value that this bean should have when injected as part of a collection
or array.

Issue: SPR-11310

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

@@ -38,11 +38,11 @@ import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.config.TypedStringValue;
 import org.springframework.beans.factory.support.AutowireCandidateQualifier;
+import org.springframework.beans.factory.support.DefaultDependencyComparator;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.GenericBeanDefinition;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.core.Ordered;
-import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.annotation.Order;
 import org.springframework.tests.sample.beans.ITestBean;
 import org.springframework.tests.sample.beans.IndexedTestBean;
@@ -51,12 +51,15 @@ import org.springframework.tests.sample.beans.TestBean;
 import org.springframework.util.SerializationTestUtils;
 
 import static org.junit.Assert.*;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.*;
 
 /**
  * @author Juergen Hoeller
  * @author Mark Fisher
  * @author Sam Brannen
  * @author Chris Beams
+ * @author Stephane Nicoll
  */
 public class AutowiredAnnotationBeanPostProcessorTests {
 
@@ -351,7 +354,7 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 	@Test
 	public void testOrderedResourceInjection() {
 		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
-		bf.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
+		bf.setDependencyComparator(DefaultDependencyComparator.INSTANCE);
 		AutowiredAnnotationBeanPostProcessor bpp = new AutowiredAnnotationBeanPostProcessor();
 		bpp.setBeanFactory(bf);
 		bf.addBeanPostProcessor(bpp);
@@ -382,10 +385,38 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 		bf.destroySingletons();
 	}
 
+	@Test
+	public void testOrderedResourceInjectionDetectsFactoryAwareComparator() {
+		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
+		DefaultDependencyComparator comparator = mock(DefaultDependencyComparator.class);
+		bf.setDependencyComparator(comparator);
+
+		AutowiredAnnotationBeanPostProcessor bpp = new AutowiredAnnotationBeanPostProcessor();
+		bpp.setBeanFactory(bf);
+		bf.addBeanPostProcessor(bpp);
+		bf.registerBeanDefinition("annotatedBean", new RootBeanDefinition(OptionalResourceInjectionBean.class));
+		TestBean tb = new TestBean();
+		bf.registerSingleton("testBean", tb);
+		IndexedTestBean itb = new IndexedTestBean();
+		bf.registerSingleton("indexedTestBean", itb);
+		final OrderedNestedTestBean ntb1 = new OrderedNestedTestBean();
+		ntb1.setOrder(2);
+		bf.registerSingleton("nestedTestBean1", ntb1);
+		final OrderedNestedTestBean ntb2 = new OrderedNestedTestBean();
+		ntb2.setOrder(1);
+		bf.registerSingleton("nestedTestBean2", ntb2);
+
+		OptionalResourceInjectionBean bean = (OptionalResourceInjectionBean) bf.getBean("annotatedBean");
+		verify(comparator, never()).compare(any(), any());
+		verify(comparator, never()).sortList(any(),any());
+		verify(comparator, times(2)).sortArray(any(),any());
+		bf.destroySingletons();
+	}
+
 	@Test
 	public void testAnnotationOrderedResourceInjection() {
 		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
-		bf.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
+		bf.setDependencyComparator(DefaultDependencyComparator.INSTANCE);
 		AutowiredAnnotationBeanPostProcessor bpp = new AutowiredAnnotationBeanPostProcessor();
 		bpp.setBeanFactory(bf);
 		bf.addBeanPostProcessor(bpp);
@@ -417,7 +448,7 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 	@Test
 	public void testOrderedCollectionResourceInjection() {
 		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
-		bf.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
+		bf.setDependencyComparator(DefaultDependencyComparator.INSTANCE);
 		AutowiredAnnotationBeanPostProcessor bpp = new AutowiredAnnotationBeanPostProcessor();
 		bpp.setBeanFactory(bf);
 		bf.addBeanPostProcessor(bpp);
@@ -458,7 +489,7 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 	@Test
 	public void testAnnotationOrderedCollectionResourceInjection() {
 		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
-		bf.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
+		bf.setDependencyComparator(DefaultDependencyComparator.INSTANCE);
 		AutowiredAnnotationBeanPostProcessor bpp = new AutowiredAnnotationBeanPostProcessor();
 		bpp.setBeanFactory(bf);
 		bf.addBeanPostProcessor(bpp);
@@ -576,7 +607,7 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 	@Test
 	public void testConstructorResourceInjectionWithMultipleOrderedCandidates() {
 		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
-		bf.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
+		bf.setDependencyComparator(DefaultDependencyComparator.INSTANCE);
 		AutowiredAnnotationBeanPostProcessor bpp = new AutowiredAnnotationBeanPostProcessor();
 		bpp.setBeanFactory(bf);
 		bf.addBeanPostProcessor(bpp);
@@ -600,7 +631,7 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 	@Test
 	public void testConstructorResourceInjectionWithMultipleCandidatesAsOrderedCollection() {
 		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
-		bf.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
+		bf.setDependencyComparator(DefaultDependencyComparator.INSTANCE);
 		AutowiredAnnotationBeanPostProcessor bpp = new AutowiredAnnotationBeanPostProcessor();
 		bpp.setBeanFactory(bf);
 		bf.addBeanPostProcessor(bpp);

spring-beans/src/test/java/org/springframework/beans/factory/support/DependencyComparatorTests.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2002-2014 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.factory.support;
+
+import static org.junit.Assert.*;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.Test;
+
+import org.springframework.core.Ordered;
+
+/**
+ *
+ * @author Stephane Nicoll
+ */
+public class DependencyComparatorTests {
+
+	private final DefaultDependencyComparator comparator = new DefaultDependencyComparator();
+
+	@Test
+	public void plainComparator() {
+		List<Object> items = new ArrayList<Object>();
+		C c = new C(5);
+		C c2 = new C(-5);
+		items.add(c);
+		items.add(c2);
+		Collections.sort(items, comparator);
+		assertOrder(items, c2, c);
+	}
+
+	private void assertOrder(List<?> actual, Object... expected) {
+		for (int i = 0; i < actual.size(); i++) {
+			assertSame("Wrong instance at index '" + i + "'", expected[i], actual.get(i));
+		}
+		assertEquals("Wrong number of items", expected.length, actual.size());
+	}
+
+	private static class C implements Ordered {
+		private final int order;
+
+		private C(int order) {
+			this.order = order;
+		}
+
+		@Override
+		public int getOrder() {
+			return order;
+		}
+	}
+
+}

spring-beans/src/test/java/org/springframework/beans/factory/support/FactoryAwareOrderProviderTests.java

@@ -0,0 +1,139 @@
+/*
+ * Copyright 2002-2014 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.factory.support;
+
+import static org.junit.Assert.*;
+import static org.mockito.BDDMockito.*;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import java.lang.reflect.Method;
+import java.util.HashMap;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestName;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.core.annotation.Order;
+import org.springframework.util.ReflectionUtils;
+
+/**
+ *
+ * @author Stephane Nicoll
+ */
+public class FactoryAwareOrderProviderTests {
+
+	@Rule
+	public final TestName name = new TestName();
+
+	@Mock
+	private ConfigurableListableBeanFactory beanFactory;
+
+	@Before
+	public void setup() {
+		MockitoAnnotations.initMocks(this);
+	}
+
+	@Test
+	public void noBeanName() {
+		FactoryAwareOrderProvider orderProvider = createOrderProvider(new HashMap<Object, String>());
+		assertNull(orderProvider.getOrder(25));
+	}
+
+	@Test
+	public void beanNameNotRegistered() {
+		HashMap<Object, String> beans = new HashMap<>();
+		beans.put(25, "myBean");
+		given(beanFactory.containsBeanDefinition("myBean")).willReturn(false);
+		FactoryAwareOrderProvider orderProvider = createOrderProvider(beans);
+		assertNull(orderProvider.getOrder(25));
+		verify(beanFactory).containsBeanDefinition("myBean");
+	}
+
+
+	@Test
+	public void beanNameNoRootBeanDefinition() {
+		HashMap<Object, String> beans = new HashMap<>();
+		beans.put(25, "myBean");
+		given(beanFactory.containsBeanDefinition("myBean")).willReturn(true);
+		given(beanFactory.getMergedBeanDefinition("myBean")).willReturn(mock(BeanDefinition.class));
+		FactoryAwareOrderProvider orderProvider = createOrderProvider(beans);
+		assertNull(orderProvider.getOrder(25));
+		verify(beanFactory).containsBeanDefinition("myBean");
+		verify(beanFactory).getMergedBeanDefinition("myBean");
+	}
+
+	@Test
+	public void beanNameNoFactory() {
+		HashMap<Object, String> beans = new HashMap<>();
+		beans.put(25, "myBean");
+		RootBeanDefinition rbd = mock(RootBeanDefinition.class);
+		given(rbd.getResolvedFactoryMethod()).willReturn(null);
+
+		given(beanFactory.containsBeanDefinition("myBean")).willReturn(true);
+		given(beanFactory.getMergedBeanDefinition("myBean")).willReturn(rbd);
+		FactoryAwareOrderProvider orderProvider = createOrderProvider(beans);
+		assertNull(orderProvider.getOrder(25));
+		verify(beanFactory).containsBeanDefinition("myBean");
+		verify(beanFactory).getMergedBeanDefinition("myBean");
+	}
+
+	@Test
+	public void beanNameFactoryNoOrderValue() {
+		HashMap<Object, String> beans = new HashMap<>();
+		beans.put(25, "myBean");
+
+		Method m = ReflectionUtils.findMethod(getClass(), name.getMethodName());
+		RootBeanDefinition rbd = mock(RootBeanDefinition.class);
+		given(rbd.getResolvedFactoryMethod()).willReturn(m);
+
+		given(beanFactory.containsBeanDefinition("myBean")).willReturn(true);
+		given(beanFactory.getMergedBeanDefinition("myBean")).willReturn(rbd);
+		FactoryAwareOrderProvider orderProvider = createOrderProvider(beans);
+		assertNull(orderProvider.getOrder(25));
+		verify(beanFactory).containsBeanDefinition("myBean");
+		verify(beanFactory).getMergedBeanDefinition("myBean");
+	}
+
+	@Test
+	@Order(500)
+	public void beanNameFactoryOrderValue() {
+		HashMap<Object, String> beans = new HashMap<>();
+		beans.put(25, "myBean");
+
+		Method m = ReflectionUtils.findMethod(getClass(), name.getMethodName());
+		RootBeanDefinition rbd = mock(RootBeanDefinition.class);
+		given(rbd.getResolvedFactoryMethod()).willReturn(m);
+
+		given(beanFactory.containsBeanDefinition("myBean")).willReturn(true);
+		given(beanFactory.getMergedBeanDefinition("myBean")).willReturn(rbd);
+		FactoryAwareOrderProvider orderProvider = createOrderProvider(beans);
+		assertEquals(Integer.valueOf(500), orderProvider.getOrder(25));
+		verify(beanFactory).containsBeanDefinition("myBean");
+		verify(beanFactory).getMergedBeanDefinition("myBean");
+	}
+
+	private FactoryAwareOrderProvider createOrderProvider(HashMap<Object, String> beans) {
+		return new FactoryAwareOrderProvider(beans, beanFactory);
+	}
+
+}