Add support for DeferredImportSelector

Add DeferredImportSelector interface that can be used to select imports
after all @Configuration beans have been processed.

spring-context/src/test/java/org/springframework/context/annotation/ImportSelectorTests.java

@@ -0,0 +1,146 @@
+/*
+ * Copyright 2002-2013 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.context.annotation;
+
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.spy;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.junit.Test;
+import org.mockito.InOrder;
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.Order;
+import org.springframework.core.type.AnnotationMetadata;
+
+/**
+ * Tests for {@link ImportSelector} and {@link DeferredImportSelector}.
+ *
+ * @author Phillip Webb
+ */
+public class ImportSelectorTests {
+
+	@Test
+	public void importSelectors() {
+		DefaultListableBeanFactory beanFactory = spy(new DefaultListableBeanFactory());
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(
+				beanFactory);
+		context.register(Config.class);
+		context.refresh();
+		context.getBean(Config.class);
+		InOrder ordered = inOrder(beanFactory);
+		ordered.verify(beanFactory).registerBeanDefinition(eq("a"), any(BeanDefinition.class));
+		ordered.verify(beanFactory).registerBeanDefinition(eq("b"), any(BeanDefinition.class));
+		ordered.verify(beanFactory).registerBeanDefinition(eq("d"), any(BeanDefinition.class));
+		ordered.verify(beanFactory).registerBeanDefinition(eq("c"), any(BeanDefinition.class));
+	}
+
+	@Sample
+	@Configuration
+	static class Config {
+	}
+
+	@Target(ElementType.TYPE)
+	@Retention(RetentionPolicy.RUNTIME)
+	@Import({ DeferredImportSelector1.class, DeferredImportSelector2.class,
+		ImportSelector1.class, ImportSelector2.class })
+	public static @interface Sample {
+	}
+
+	public static class ImportSelector1 implements ImportSelector {
+
+		@Override
+		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
+			return new String[] { ImportedSelector1.class.getName() };
+		}
+	}
+
+	public static class ImportSelector2 implements ImportSelector {
+
+		@Override
+		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
+			return new String[] { ImportedSelector2.class.getName() };
+		}
+	}
+
+	public static class DeferredImportSelector1 implements DeferredImportSelector, Ordered {
+
+		@Override
+		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
+			return new String[] { DeferredImportedSelector1.class.getName() };
+		}
+
+		@Override
+		public int getOrder() {
+			return Ordered.LOWEST_PRECEDENCE;
+		}
+	}
+
+	@Order(Ordered.HIGHEST_PRECEDENCE)
+	public static class DeferredImportSelector2 implements DeferredImportSelector {
+
+		@Override
+		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
+			return new String[] { DeferredImportedSelector2.class.getName() };
+		}
+
+	}
+
+	@Configuration
+	public static class ImportedSelector1 {
+
+		@Bean
+		public String a() {
+			return "a";
+		}
+	}
+
+	@Configuration
+	public static class ImportedSelector2 {
+
+		@Bean
+		public String b() {
+			return "b";
+		}
+	}
+
+	@Configuration
+	public static class DeferredImportedSelector1 {
+
+		@Bean
+		public String c() {
+			return "c";
+		}
+	}
+
+	@Configuration
+	public static class DeferredImportedSelector2 {
+
+		@Bean
+		public String d() {
+			return "d";
+		}
+	}
+
+}