SPR-5682:

* polishing for ConfigurationClassApplicationContext & tests
* added ConfigurationClassWebApplicationContext & tests
* next: refactoring out duplications between ConfigurationClassApplicationContext & ConfigurationClassWebApplicationContext

org.springframework.web/src/main/java/org/springframework/web/context/support/ConfigurationClassWebApplicationContext.java

@@ -0,0 +1,128 @@
+/*
+ * Copyright 2002-2009 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.web.context.support;
+
+import java.io.IOException;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.beans.factory.support.AbstractBeanDefinition;
+import org.springframework.beans.factory.support.BeanDefinitionBuilder;
+import org.springframework.beans.factory.support.DefaultBeanNameGenerator;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.context.annotation.AnnotationConfigUtils;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.ConfigurationClassPostProcessor;
+import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.StringUtils;
+
+
+/**
+ * {@link org.springframework.web.context.WebApplicationContext} implementation
+ * which takes its configuration from {@link Configuration @Configuration} classes.
+ * This is essentially the equivalent of
+ * {@link org.springframework.context.annotation.ConfigurationClassApplicationContext}
+ * for a web environment.
+ *
+ * <p>To make use of this application context, the "contextClass" context-param for
+ * ContextLoader and/or "contextClass" init-param for FrameworkServlet must be set to
+ * the fully-qualified name of this class.
+ *
+ * <p>Unlike {@link XmlWebApplicationContext}, no default configuration class locations
+ * are assumed. Rather, it is a requirement to set the "contextConfigLocation"
+ * context-param for ContextLoader and/or "contextConfigLocation" init-param for
+ * FrameworkServlet. If these params are not set, an IllegalArgumentException will be thrown.
+ *
+ * <p>Note: In case of multiple {@literal @Configuration} classes, later {@literal @Bean}
+ * definitions will override ones defined in earlier loaded files. This can be leveraged
+ * to deliberately override certain bean definitions via an extra Configuration class.
+ *
+ * @author Chris Beams
+ * @see org.springframework.context.annotation.ConfigurationClassApplicationContext
+ */
+public class ConfigurationClassWebApplicationContext extends AbstractRefreshableWebApplicationContext {
+
+	/**
+	 * @throws IllegalArgumentException if configLocations array is null or empty
+	 * @throws IOException if any one configLocation is not loadable as a class
+	 * @throws IllegalArgumentException if any one loaded class is not annotated with {@literal @Configuration}
+	 * @see #getConfigLocations()
+	 */
+	@Override
+	protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory)
+			throws IOException, BeansException {
+
+	 	Assert.notEmpty(getConfigLocations(),
+	 			"No config locations were specified. Is the 'contextConfigLocations' " +
+	 			"context-param and/or init-param set properly in web.xml?");
+
+		Set<Class<?>> configClasses = new LinkedHashSet<Class<?>>();
+
+		for (String configLocation : getConfigLocations()) {
+			try {
+				Class<?> configClass = ClassUtils.getDefaultClassLoader().loadClass(configLocation);
+				if (AnnotationUtils.findAnnotation(configClass, Configuration.class) == null) {
+					throw new IllegalArgumentException("Class [" + configClass.getName() + "] is not annotated with @Configuration");
+				}
+				configClasses.add(configClass);
+			} catch (ClassNotFoundException ex) {
+				throw new IOException("Could not load @Configuration class [" + configLocation + "]", ex);
+			}
+		}
+
+		// @Autowired and friends must be enabled by default when processing @Configuration classes
+		AnnotationConfigUtils.registerAnnotationConfigProcessors(beanFactory);
+
+		for (Class<?> configClass : configClasses) {
+			AbstractBeanDefinition def = BeanDefinitionBuilder.rootBeanDefinition(configClass).getBeanDefinition();
+
+			String name = AnnotationUtils.findAnnotation(configClass, Configuration.class).value();
+			if (!StringUtils.hasLength(name)) {
+				name = new DefaultBeanNameGenerator().generateBeanName(def, beanFactory);
+			}
+
+			beanFactory.registerBeanDefinition(name, def);
+		}
+
+		new ConfigurationClassPostProcessor().postProcessBeanFactory(beanFactory);
+	}
+
+	@SuppressWarnings("unchecked")
+	public <T> T getBean(Class<T> requiredType) {
+		Assert.notNull(requiredType, "requiredType may not be null");
+
+		Map<String, ?> beansOfType = this.getBeansOfType(requiredType);
+
+		switch (beansOfType.size()) {
+			case 0:
+				throw new NoSuchBeanDefinitionException(requiredType);
+			case 1:
+				return (T) beansOfType.values().iterator().next();
+			default:
+				throw new NoSuchBeanDefinitionException(requiredType,
+						beansOfType.size() + " matching bean definitions found " +
+						"(" + StringUtils.collectionToCommaDelimitedString(beansOfType.keySet()) + "). " +
+						"Consider qualifying with getBean(Class<T> beanType, String beanName) or " +
+						"declaring one bean definition as @Primary");
+		}
+	}
+}