MavenDIExtension.java
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.maven.api.di.testing;
import java.io.File;
import org.apache.maven.di.Injector;
import org.apache.maven.di.Key;
import org.apache.maven.di.impl.DIException;
import org.junit.jupiter.api.extension.AfterEachCallback;
import org.junit.jupiter.api.extension.BeforeEachCallback;
import org.junit.jupiter.api.extension.ExtensionContext;
/**
* JUnit Jupiter extension that provides dependency injection support for Maven tests.
* This extension manages the lifecycle of a DI container for each test method execution,
* automatically performing injection into test instances and cleanup.
*
* <p>This is a modernized version of the original Plexus test support, adapted for
* Maven's new DI framework and JUnit Jupiter.</p>
*
* <p>Usage example:</p>
* <pre>
* {@code
* @ExtendWith(MavenDIExtension.class)
* class MyTest {
* @Inject
* private MyComponent component;
*
* @Test
* void testSomething() {
* // component is automatically injected
* }
* }
* }
* </pre>
*/
public class MavenDIExtension implements BeforeEachCallback, AfterEachCallback {
protected static ExtensionContext context;
protected Injector injector;
protected static String basedir;
/**
* Initializes the test environment before each test method execution.
* Sets up the base directory and DI container, then performs injection into the test instance.
*
* @param context The extension context provided by JUnit
* @throws Exception if initialization fails
*/
@Override
public void beforeEach(ExtensionContext context) throws Exception {
basedir = getBasedir();
setContext(context);
getInjector().bindInstance((Class<Object>) context.getRequiredTestClass(), context.getRequiredTestInstance());
getInjector().injectInstance(context.getRequiredTestInstance());
}
/**
* Stores the extension context for use during test execution.
*
* @param context The extension context to store
*/
protected void setContext(ExtensionContext context) {
MavenDIExtension.context = context;
}
/**
* Creates and configures the DI container for test execution.
* Performs component discovery and sets up basic bindings.
*
* @throws IllegalStateException if the ExtensionContext is null, the required test class is unavailable,
* the required test instance is unavailable, or if container setup fails
*/
protected void setupContainer() {
if (context == null) {
throw new IllegalStateException("ExtensionContext must not be null");
}
final Class<?> testClass = context.getRequiredTestClass();
if (testClass == null) {
throw new IllegalStateException("Required test class is not available in ExtensionContext");
}
final Object testInstance = context.getRequiredTestInstance();
if (testInstance == null) {
throw new IllegalStateException("Required test instance is not available in ExtensionContext");
}
try {
injector = Injector.create();
injector.bindInstance(ExtensionContext.class, context);
injector.discover(testClass.getClassLoader());
injector.bindInstance(Injector.class, injector);
injector.bindInstance(testClass.asSubclass(Object.class), (Object) testInstance); // Safe generics handling
} catch (final Exception e) {
throw new IllegalStateException(
String.format(
"Failed to set up DI injector for test class '%s': %s",
testClass.getName(), e.getMessage()),
e);
}
}
/**
* Cleans up resources after each test method execution.
* Currently a placeholder for future cleanup implementation.
*
* @param context The extension context provided by JUnit
*/
@Override
public void afterEach(ExtensionContext context) throws Exception {
if (injector != null) {
injector.dispose();
injector = null;
}
}
/**
* Returns the DI injector, creating it if necessary.
*
* @return The configured injector instance
*/
public Injector getInjector() {
if (injector == null) {
setupContainer();
}
return injector;
}
/**
* Looks up a component of the specified type from the container.
*
* @param <T> The component type
* @param componentClass The class of the component to look up
* @return The component instance
* @throws DIException if lookup fails
*/
protected <T> T lookup(Class<T> componentClass) throws DIException {
return getInjector().getInstance(componentClass);
}
/**
* Looks up a component of the specified type and role hint from the container.
*
* @param <T> The component type
* @param componentClass The class of the component to look up
* @param roleHint The role hint for the component
* @return The component instance
* @throws DIException if lookup fails
*/
protected <T> T lookup(Class<T> componentClass, String roleHint) throws DIException {
return getInjector().getInstance(Key.ofType(componentClass, roleHint));
}
/**
* Looks up a component of the specified type and qualifier from the container.
*
* @param <T> The component type
* @param componentClass The class of the component to look up
* @param qualifier The qualifier for the component
* @return The component instance
* @throws DIException if lookup fails
*/
protected <T> T lookup(Class<T> componentClass, Object qualifier) throws DIException {
return getInjector().getInstance(Key.ofType(componentClass, qualifier));
}
/**
* Releases a component back to the container.
* Currently a placeholder for future implementation.
*
* @param component The component to release
* @throws DIException if release fails
*/
protected void release(Object component) throws DIException {
// TODO: implement
// getInjector().release(component);
}
/**
* Creates a File object for a path relative to the base directory.
*
* @param path The relative path
* @return A File object representing the path
*/
public static File getTestFile(String path) {
return new File(getBasedir(), path);
}
/**
* Creates a File object for a path relative to a specified base directory.
*
* @param basedir The base directory path
* @param path The relative path
* @return A File object representing the path
*/
public static File getTestFile(String basedir, String path) {
File basedirFile = new File(basedir);
if (!basedirFile.isAbsolute()) {
basedirFile = getTestFile(basedir);
}
return new File(basedirFile, path);
}
/**
* Returns the absolute path for a path relative to the base directory.
*
* @param path The relative path
* @return The absolute path
*/
public static String getTestPath(String path) {
return getTestFile(path).getAbsolutePath();
}
/**
* Returns the absolute path for a path relative to a specified base directory.
*
* @param basedir The base directory path
* @param path The relative path
* @return The absolute path
*/
public static String getTestPath(String basedir, String path) {
return getTestFile(basedir, path).getAbsolutePath();
}
/**
* Returns the base directory for test execution.
* Uses the "basedir" system property if set, otherwise uses the current directory.
*
* @return The base directory path
*/
public static String getBasedir() {
if (basedir != null) {
return basedir;
}
basedir = System.getProperty("basedir");
if (basedir == null) {
basedir = new File("").getAbsolutePath();
}
return basedir;
}
}