Improve documentation of SmartContextLoader contracts

Author: sbrannen

spring-test/src/main/java/org/springframework/test/context/SmartContextLoader.java

@@ -20,15 +20,17 @@
 import org.springframework.lang.Nullable;
 
 /**
- * Strategy interface for loading an {@link ApplicationContext application context}
- * for an integration test managed by the Spring TestContext Framework.
+ * Strategy interface for loading an {@link ApplicationContext} for an integration
+ * test managed by the Spring TestContext Framework.
  *
  * <p>The {@code SmartContextLoader} SPI supersedes the {@link ContextLoader} SPI
  * introduced in Spring 2.5: a {@code SmartContextLoader} can choose to process
- * either resource locations or annotated classes. Furthermore, a
- * {@code SmartContextLoader} can set active bean definition profiles in the
- * context that it loads (see {@link MergedContextConfiguration#getActiveProfiles()}
- * and {@link #loadContext(MergedContextConfiguration)}).
+ * resource locations, annotated classes, or a combination of both. Furthermore, a
+ * {@code SmartContextLoader} can configure the context that it
+ * {@linkplain #loadContext(MergedContextConfiguration) loads} based on any
+ * properties available in the provided {@link MergedContextConfiguration}. For
+ * example, active bean definition profiles can be configured for the context
+ * based on {@link MergedContextConfiguration#getActiveProfiles()}.
  *
  * <p>See the Javadoc for {@link ContextConfiguration @ContextConfiguration}
  * for a definition of <em>annotated class</em>.
@@ -45,11 +47,8 @@
  * hierarchy of the root test class and then supplied to
  * {@link #loadContext(MergedContextConfiguration) loadContext()}.
  *
- * <p>Even though {@code SmartContextLoader} extends {@code ContextLoader},
- * clients should favor {@code SmartContextLoader}-specific methods over those
- * defined in {@code ContextLoader}, particularly because a
- * {@code SmartContextLoader} may choose not to support methods defined in the
- * {@code ContextLoader} SPI.
+ * <p>NOTE: As of Spring Framework 6.0, {@code SmartContextLoader} no longer
+ * supports methods defined in the {@code ContextLoader} SPI.
  *
  * <p>Concrete implementations must provide a {@code public} no-args constructor.
  *
@@ -58,43 +57,45 @@
  * <li>{@link org.springframework.test.context.support.DelegatingSmartContextLoader DelegatingSmartContextLoader}</li>
  * <li>{@link org.springframework.test.context.support.AnnotationConfigContextLoader AnnotationConfigContextLoader}</li>
  * <li>{@link org.springframework.test.context.support.GenericXmlContextLoader GenericXmlContextLoader}</li>
+ * <li>{@link org.springframework.test.context.support.GenericGroovyXmlContextLoader GenericGroovyXmlContextLoader}</li>
  * <li>{@link org.springframework.test.context.web.WebDelegatingSmartContextLoader WebDelegatingSmartContextLoader}</li>
  * <li>{@link org.springframework.test.context.web.AnnotationConfigWebContextLoader AnnotationConfigWebContextLoader}</li>
  * <li>{@link org.springframework.test.context.web.GenericXmlWebContextLoader GenericXmlWebContextLoader}</li>
+ * <li>{@link org.springframework.test.context.web.GenericGroovyXmlWebContextLoader GenericGroovyXmlWebContextLoader}</li>
  * </ul>
  *
  * @author Sam Brannen
  * @since 3.1
  * @see ContextConfiguration
  * @see ActiveProfiles
+ * @see TestPropertySource
  * @see ContextConfigurationAttributes
  * @see MergedContextConfiguration
  */
 public interface SmartContextLoader extends ContextLoader {
 
 	/**
-	 * Processes the {@link ContextConfigurationAttributes} for a given test class.
+	 * Process the {@link ContextConfigurationAttributes} for a given test class.
 	 * <p>Concrete implementations may choose to <em>modify</em> the {@code locations}
-	 * or {@code classes} in the supplied {@link ContextConfigurationAttributes},
+	 * or {@code classes} in the supplied {@code ContextConfigurationAttributes},
 	 * <em>generate</em> default configuration locations, or <em>detect</em>
 	 * default configuration classes if the supplied values are {@code null}
 	 * or empty.
-	 * <p><b>Note</b>: in contrast to a standard {@code ContextLoader}, a
-	 * {@code SmartContextLoader} <b>must</b> <em>preemptively</em> verify that
-	 * a generated or detected default actually exists before setting the corresponding
-	 * {@code locations} or {@code classes} property in the supplied
-	 * {@link ContextConfigurationAttributes}. Consequently, leaving the
-	 * {@code locations} or {@code classes} property empty signals that
-	 * this {@code SmartContextLoader} was not able to generate or detect defaults.
+	 * <p><b>Note</b>: a {@code SmartContextLoader} must <em>preemptively</em>
+	 * verify that a generated or detected default actually exists before setting
+	 * the corresponding {@code locations} or {@code classes} property in the
+	 * supplied {@code ContextConfigurationAttributes}. Consequently, leaving the
+	 * {@code locations} or {@code classes} property empty signals that this
+	 * {@code SmartContextLoader} was not able to generate or detect defaults.
 	 * @param configAttributes the context configuration attributes to process
 	 */
 	void processContextConfiguration(ContextConfigurationAttributes configAttributes);
 
 	/**
-	 * Loads a new {@link ApplicationContext context} based on the supplied
+	 * Load a new {@linkplain ApplicationContext context} based on the supplied
 	 * {@link MergedContextConfiguration merged context configuration},
-	 * configures the context, and finally returns the context in a fully
-	 * <em>refreshed</em> state.
+	 * configure the context, and return the context in a fully <em>refreshed</em>
+	 * state.
 	 * <p>Concrete implementations should register annotation configuration
 	 * processors with bean factories of
 	 * {@link ApplicationContext application contexts} loaded by this
@@ -103,22 +104,35 @@ public interface SmartContextLoader extends ContextLoader {
 	 * {@link org.springframework.beans.factory.annotation.Autowired @Autowired},
 	 * {@link jakarta.annotation.Resource @Resource}, and
 	 * {@link jakarta.inject.Inject @Inject}. In addition, concrete implementations
-	 * should set the active bean definition profiles in the context's
-	 * {@link org.springframework.core.env.Environment Environment}.
-	 * <p>Any {@code ApplicationContext} loaded by a
-	 * {@code SmartContextLoader} <strong>must</strong> register a JVM
-	 * shutdown hook for itself. Unless the context gets closed early, all context
-	 * instances will be automatically closed on JVM shutdown. This allows for
-	 * freeing of external resources held by beans within the context (e.g.,
-	 * temporary files).
+	 * should perform the following actions.
+	 * <ul>
+	 * <li>Set the parent {@code ApplicationContext} if appropriate (see
+	 * {@link MergedContextConfiguration#getParent()}).</li>
+	 * <li>Set the active bean definition profiles in the context's
+	 * {@link org.springframework.core.env.Environment Environment} (see
+	 * {@link MergedContextConfiguration#getActiveProfiles()}).</li>
+	 * <li>Add test {@link org.springframework.core.env.PropertySource PropertySources}
+	 * to the {@code Environment} (see
+	 * {@link MergedContextConfiguration#getPropertySourceLocations()},
+	 * {@link MergedContextConfiguration#getPropertySourceProperties()}, and
+	 * {@link org.springframework.test.context.support.TestPropertySourceUtils
+	 * TestPropertySourceUtils}).</li>
+	 * <li>Invoke {@link org.springframework.context.ApplicationContextInitializer
+	 * ApplicationContextInitializers} (see
+	 * {@link MergedContextConfiguration#getContextInitializerClasses()}).</li>
+	 * <li>Invoke {@link ContextCustomizer ContextCustomizers} (see
+	 * {@link MergedContextConfiguration#getContextCustomizers()}).</li>
+	 * <li>Register a JVM shutdown hook for the {@link ApplicationContext}. Unless
+	 * the context gets closed early, all context instances will be automatically
+	 * closed on JVM shutdown. This allows for freeing of external resources held
+	 * by beans within the context &mdash; for example, temporary files.</li>
+	 * </ul>
 	 * @param mergedConfig the merged context configuration to use to load the
 	 * application context
 	 * @return a new application context
 	 * @throws Exception if context loading failed
 	 * @see #processContextConfiguration(ContextConfigurationAttributes)
-	 * @see org.springframework.context.annotation.AnnotationConfigUtils
-	 * #registerAnnotationConfigProcessors(org.springframework.beans.factory.support.BeanDefinitionRegistry)
-	 * @see MergedContextConfiguration#getActiveProfiles()
+	 * @see org.springframework.context.annotation.AnnotationConfigUtils#registerAnnotationConfigProcessors(org.springframework.beans.factory.support.BeanDefinitionRegistry)
 	 * @see org.springframework.context.ConfigurableApplicationContext#getEnvironment()
 	 */
 	ApplicationContext loadContext(MergedContextConfiguration mergedConfig) throws Exception;