/*
* Copyright 2002-2016 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.test.context;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* {@code @ContextHierarchy} is a class-level annotation that is used to define
* a hierarchy of {@link org.springframework.context.ApplicationContext
* ApplicationContexts} for integration tests.
*
* <h3>Examples</h3>
* <p>The following JUnit-based examples demonstrate common configuration
* scenarios for integration tests that require the use of context hierarchies.
*
* <h4>Single Test Class with Context Hierarchy</h4>
* <p>{@code ControllerIntegrationTests} represents a typical integration testing
* scenario for a Spring MVC web application by declaring a context hierarchy
* consisting of two levels, one for the <em>root</em> {@code WebApplicationContext}
* (with {@code TestAppConfig}) and one for the <em>dispatcher servlet</em>
* {@code WebApplicationContext} (with {@code WebConfig}). The {@code
* WebApplicationContext} that is <em>autowired</em> into the test instance is
* the one for the child context (i.e., the lowest context in the hierarchy).
*
* <pre class="code">
* @RunWith(SpringRunner.class)
* @WebAppConfiguration
* @ContextHierarchy({
* @ContextConfiguration(classes = TestAppConfig.class),
* @ContextConfiguration(classes = WebConfig.class)
* })
* public class ControllerIntegrationTests {
*
* @Autowired
* private WebApplicationContext wac;
*
* // ...
* }</pre>
*
* <h4>Class Hierarchy with Implicit Parent Context</h4>
* <p>The following test classes define a context hierarchy within a test class
* hierarchy. {@code AbstractWebTests} declares the configuration for a root
* {@code WebApplicationContext} in a Spring-powered web application. Note,
* however, that {@code AbstractWebTests} does not declare {@code @ContextHierarchy};
* consequently, subclasses of {@code AbstractWebTests} can optionally participate
* in a context hierarchy or follow the standard semantics for {@code @ContextConfiguration}.
* {@code SoapWebServiceTests} and {@code RestWebServiceTests} both extend
* {@code AbstractWebTests} and define a context hierarchy via {@code @ContextHierarchy}.
* The result is that three application contexts will be loaded (one for each
* declaration of {@code @ContextConfiguration}, and the application context
* loaded based on the configuration in {@code AbstractWebTests} will be set as
* the parent context for each of the contexts loaded for the concrete subclasses.
*
* <pre class="code">
* @RunWith(SpringRunner.class)
* @WebAppConfiguration
* @ContextConfiguration("file:src/main/webapp/WEB-INF/applicationContext.xml")
* public abstract class AbstractWebTests {}
*
* @ContextHierarchy(@ContextConfiguration("/spring/soap-ws-config.xml")
* public class SoapWebServiceTests extends AbstractWebTests {}
*
* @ContextHierarchy(@ContextConfiguration("/spring/rest-ws-config.xml")
* public class RestWebServiceTests extends AbstractWebTests {}</pre>
*
* <h4>Class Hierarchy with Merged Context Hierarchy Configuration</h4>
* <p>The following classes demonstrate the use of <em>named</em> hierarchy levels
* in order to <em>merge</em> the configuration for specific levels in a context
* hierarchy. {@code BaseTests} defines two levels in the hierarchy, {@code parent}
* and {@code child}. {@code ExtendedTests} extends {@code BaseTests} and instructs
* the Spring TestContext Framework to merge the context configuration for the
* {@code child} hierarchy level, simply by ensuring that the names declared via
* {@link ContextConfiguration#name} are both {@code "child"}. The result is that
* three application contexts will be loaded: one for {@code "/app-config.xml"},
* one for {@code "/user-config.xml"}, and one for <code>{"/user-config.xml",
* "/order-config.xml"}</code>. As with the previous example, the application
* context loaded from {@code "/app-config.xml"} will be set as the parent context
* for the contexts loaded from {@code "/user-config.xml"} and <code>{"/user-config.xml",
* "/order-config.xml"}</code>.
*
* <pre class="code">
* @RunWith(SpringRunner.class)
* @ContextHierarchy({
* @ContextConfiguration(name = "parent", locations = "/app-config.xml"),
* @ContextConfiguration(name = "child", locations = "/user-config.xml")
* })
* public class BaseTests {}
*
* @ContextHierarchy(
* @ContextConfiguration(name = "child", locations = "/order-config.xml")
* )
* public class ExtendedTests extends BaseTests {}</pre>
*
* <h4>Class Hierarchy with Overridden Context Hierarchy Configuration</h4>
* <p>In contrast to the previous example, this example demonstrates how to
* <em>override</em> the configuration for a given named level in a context hierarchy
* by setting the {@link ContextConfiguration#inheritLocations} flag to {@code false}.
* Consequently, the application context for {@code ExtendedTests} will be loaded
* only from {@code "/test-user-config.xml"} and will have its parent set to the
* context loaded from {@code "/app-config.xml"}.
*
* <pre class="code">
* @RunWith(SpringRunner.class)
* @ContextHierarchy({
* @ContextConfiguration(name = "parent", locations = "/app-config.xml"),
* @ContextConfiguration(name = "child", locations = "/user-config.xml")
* })
* public class BaseTests {}
*
* @ContextHierarchy(
* @ContextConfiguration(name = "child", locations = "/test-user-config.xml", inheritLocations = false)
* )
* public class ExtendedTests extends BaseTests {}</pre>
*
* <p>As of Spring Framework 4.0, this annotation may be used as a
* <em>meta-annotation</em> to create custom <em>composed annotations</em>.
*
* @author Sam Brannen
* @since 3.2.2
* @see ContextConfiguration
* @see org.springframework.context.ApplicationContext
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface ContextHierarchy {
/**
* A list of {@link ContextConfiguration @ContextConfiguration} instances,
* each of which defines a level in the context hierarchy.
* <p>If you need to merge or override the configuration for a given level
* of the context hierarchy within a test class hierarchy, you must explicitly
* name that level by supplying the same value to the {@link ContextConfiguration#name
* name} attribute in {@code @ContextConfiguration} at each level in the
* class hierarchy. See the class-level Javadoc for examples.
*/
ContextConfiguration[] value();
}