[SPR-6184] Simplifying ContextLoader implmementation:

- Removed AbstractGenericContextLoader's createGenericApplicationContext() method.
- AnnotationConfigContextLoader now uses an AnnotatedBeanDefinitionReader instead of working with an AnnotationConfigApplicationContext.
- AnnotationConfigContextLoader now uses the supplied GenericApplicationContext to load configuration classes.

org.springframework.test/src/main/java/org/springframework/test/context/ContextLoaderUtils.java

@@ -137,8 +137,8 @@ abstract class ContextLoaderUtils {
 		}
 
 		try {
-			ContextConfiguration contextConfiguration = clazz.getAnnotation(annotationType);
 			if (logger.isTraceEnabled()) {
+				ContextConfiguration contextConfiguration = clazz.getAnnotation(annotationType);
 				logger.trace("Using default ContextLoader class [" + defaultContextLoaderClassName
 						+ "] for @ContextConfiguration [" + contextConfiguration + "] and class [" + clazz + "]");
 			}

org.springframework.test/src/main/java/org/springframework/test/context/ResourceTypeAwareContextLoader.java

@@ -25,6 +25,9 @@ package org.springframework.test.context;
  * resource locations; as of Spring 3.1 context loaders may choose to
  * support either String-based or Class-based resources (but not both).
  * 
+ * <p>TODO Document how classes are converted into String[] locations
+ * and passed into the corresponding methods in the ContextLoader API.
+ * 
  * <p>If a context loader does not implement this interface it is assumed
  * that the loader supports String-based resource locations.
  *

org.springframework.test/src/main/java/org/springframework/test/context/support/AbstractGenericContextLoader.java

@@ -28,15 +28,17 @@ import org.springframework.util.StringUtils;
 /**
  * Abstract, generic extension of {@link AbstractContextLoader} which loads a
  * {@link GenericApplicationContext} from the <em>locations</em> provided to
- * {@link #loadContext(String...)}.
+ * {@link #loadContext loadContext()}.
  *
- * <p>Concrete subclasses must provide an appropriate
- * {@link #createBeanDefinitionReader(GenericApplicationContext) BeanDefinitionReader}.
+ * <p>Concrete subclasses must provide an appropriate implementation of
+ * {@link #createBeanDefinitionReader createBeanDefinitionReader()},
+ * potentially overriding {@link #loadBeanDefinitions loadBeanDefinitions()}
+ * in addition.
  *
  * @author Sam Brannen
  * @author Juergen Hoeller
  * @since 2.5
- * @see #loadContext(String...)
+ * @see #loadContext
  */
 public abstract class AbstractGenericContextLoader extends AbstractContextLoader {
 
@@ -47,8 +49,7 @@ public abstract class AbstractGenericContextLoader extends AbstractContextLoader
 	 * Loads a Spring ApplicationContext from the supplied <code>locations</code>.
 	 * <p>Implementation details:
 	 * <ul>
-	 * <li>Delegates to {@link #createGenericApplicationContext()} to
-	 * create a {@link GenericApplicationContext} instance.</li>
+	 * <li>Creates a {@link GenericApplicationContext} instance.</li>
 	 * <li>Calls {@link #prepareContext(GenericApplicationContext)} to
 	 * prepare the context.</li>
 	 * <li>Calls {@link #customizeBeanFactory(DefaultListableBeanFactory)} to
@@ -72,7 +73,7 @@ public abstract class AbstractGenericContextLoader extends AbstractContextLoader
 			logger.debug(String.format("Loading ApplicationContext for locations [%s].",
 				StringUtils.arrayToCommaDelimitedString(locations)));
 		}
-		GenericApplicationContext context = createGenericApplicationContext();
+		GenericApplicationContext context = new GenericApplicationContext();
 		prepareContext(context);
 		customizeBeanFactory(context.getDefaultListableBeanFactory());
 		loadBeanDefinitions(context, locations);
@@ -83,20 +84,6 @@ public abstract class AbstractGenericContextLoader extends AbstractContextLoader
 		return context;
 	}
 
-	/**
-	 * Factory method for creating a new {@link GenericApplicationContext} 
-	 * to be used by this <code>ContextLoader</code>.
-	 * <p>The default implementation returns an instance of
-	 * {@link GenericApplicationContext}. Can be overridden in subclasses
-	 * to return a specific subclass of <code>GenericApplicationContext</code>.
-	 * @return a new <code>GenericApplicationContext</code>
-	 * @since 3.1
-	 * @see #loadContext
-	 */
-	protected GenericApplicationContext createGenericApplicationContext() {
-		return new GenericApplicationContext();
-	}
-
 	/**
 	 * Prepare the {@link GenericApplicationContext} created by this <code>ContextLoader</code>.
 	 * Called <i>before</> bean definitions are read.
@@ -132,10 +119,10 @@ public abstract class AbstractGenericContextLoader extends AbstractContextLoader
 	 * {@link BeanDefinitionReader#loadBeanDefinitions(String) load} the
 	 * bean definitions.
 	 * <p>Subclasses must provide an appropriate implementation of
-	 * {@link #createBeanDefinitionReader}.
-	 * Alternatively subclasses may provide a <em>no-op</em> implementation
-	 * of {@link #createBeanDefinitionReader} and override this method to
-	 * provide a custom strategy for loading or registering bean definitions.
+	 * {@link #createBeanDefinitionReader}. Alternatively subclasses may
+	 * provide a <em>no-op</em> implementation of {@link #createBeanDefinitionReader}
+	 * and override this method to provide a custom strategy for loading or
+	 * registering bean definitions.
 	 * @param context the context into which the bean definitions should be loaded
 	 * @param locations the resource locations from which to load the bean definitions
 	 * @since 3.1
@@ -147,8 +134,7 @@ public abstract class AbstractGenericContextLoader extends AbstractContextLoader
 
 	/**
 	 * Factory method for creating a new {@link BeanDefinitionReader} for
-	 * loading bean definitions into the supplied
-	 * {@link GenericApplicationContext context}.
+	 * loading bean definitions into the supplied {@link GenericApplicationContext context}.
 	 * @param context the context for which the BeanDefinitionReader should be created
 	 * @return a BeanDefinitionReader for the supplied context
 	 * @see #loadBeanDefinitions

org.springframework.test/src/main/java/org/springframework/test/context/support/AnnotationConfigContextLoader.java

@@ -19,7 +19,7 @@ package org.springframework.test.context.support;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.beans.factory.support.BeanDefinitionReader;
-import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.AnnotatedBeanDefinitionReader;
 import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.test.context.ContextLoader;
 import org.springframework.util.Assert;
@@ -27,8 +27,7 @@ import org.springframework.util.ObjectUtils;
 
 /**
  * Concrete implementation of {@link AbstractGenericContextLoader} which
- * creates an {@link AnnotationConfigApplicationContext} and registers
- * bean definitions from
+ * registers bean definitions from
  * {@link org.springframework.context.annotation.Configuration configuration classes}.
  * 
  * <p>This <code>ContextLoader</code> supports class-based context configuration
@@ -46,44 +45,33 @@ public class AnnotationConfigContextLoader extends AbstractGenericContextLoader
 	private static final Log logger = LogFactory.getLog(AnnotationConfigContextLoader.class);
 
 
-	/**
-	 * Creates a new {@link AnnotationConfigApplicationContext}.
-	 */
-	@Override
-	protected GenericApplicationContext createGenericApplicationContext() {
-		return new AnnotationConfigApplicationContext();
-	}
-
 	/**
 	 * Registers {@link org.springframework.context.annotation.Configuration configuration classes}
-	 * in the supplied {@link AnnotationConfigApplicationContext} from the specified
+	 * in the supplied {@link GenericApplicationContext context} from the specified
 	 * class names.
 	 * 
 	 * <p>Each class name must be the <em>fully qualified class name</em> of an
-	 * annotated configuration class, component, or feature specification. The
-	 * <code>AnnotationConfigApplicationContext</code> assumes the responsibility
-	 * of loading the appropriate bean definitions.
+	 * annotated configuration class, component, or feature specification. An
+	 * {@link AnnotatedBeanDefinitionReader} is used to register the appropriate
+	 * bean definitions.
+	 * 
+	 * <p>Note that this method does not call {@link #createBeanDefinitionReader}
+	 * since <code>AnnotatedBeanDefinitionReader</code> is not an instance of
+	 * {@link BeanDefinitionReader}.
 	 * 
-	 * <p>Note that this method does not call {@link #createBeanDefinitionReader}.
 	 * @param context the context in which the configuration classes should be registered
 	 * @param classNames the names of configuration classes to register in the context
-	 * @throws IllegalArgumentException if the supplied context is not an instance of
-	 * <code>AnnotationConfigApplicationContext</code> or if a supplied class name
-	 * does not represent a class
-	 * @see #createGenericApplicationContext()
+	 * @throws IllegalArgumentException if a supplied class name does not represent a class
 	 */
 	@Override
 	protected void loadBeanDefinitions(GenericApplicationContext context, String... classNames) {
 
-		Assert.isInstanceOf(AnnotationConfigApplicationContext.class, context,
-			"context must be an instance of AnnotationConfigApplicationContext");
-
 		Class<?>[] configClasses = new Class<?>[classNames.length];
 
 		for (int i = 0; i < classNames.length; i++) {
 			String className = classNames[i];
 			try {
-				configClasses[i] = (Class<?>) getClass().getClassLoader().loadClass(className);
+				configClasses[i] = (Class<?>) context.getClassLoader().loadClass(className);
 			}
 			catch (ClassNotFoundException e) {
 				throw new IllegalArgumentException(String.format(
@@ -94,7 +82,7 @@ public class AnnotationConfigContextLoader extends AbstractGenericContextLoader
 		if (logger.isDebugEnabled()) {
 			logger.debug("Registering configuration classes: " + ObjectUtils.nullSafeToString(configClasses));
 		}
-		((AnnotationConfigApplicationContext) context).register(configClasses);
+		new AnnotatedBeanDefinitionReader(context).register(configClasses);
 	}
 
 	/**