Sample test case showing how to use Spring JavaConfig with qualifiers

JavaConfigWithQualifierTests.java

/*
 * Copyright 2013 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.springsource.restbucks;

import static org.hamcrest.CoreMatchers.*;
import static org.junit.Assert.*;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

/**
 * @author Oliver Gierke
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration
public class FooTest {

	static MyComponent first, second, third;

	@BeforeClass
	public static void setUp() {
		first = new MyComponent();
		second = new MyComponent();
		third = new MyComponent();
	}

	@Configuration
	static class Config {

		@Bean
		@Qualifier("black")
		public MyComponent first() {
			return first;
		}

		@Bean
		@Qualifier("white")
		public MyComponent second() {
			return second;
		}

		@Bean
		@MyQualifier
		public MyComponent third() {
			return third;
		}
	}

	static class MyComponent {

	}

	@Target({ ElementType.FIELD, ElementType.METHOD })
	@Retention(RetentionPolicy.RUNTIME)
	@Qualifier
	static @interface MyQualifier {

	}

	@Autowired
	@Qualifier("black")
	MyComponent wiredFirst;

	@Autowired
	@Qualifier("white")
	MyComponent wiredSecond;

	@Autowired
	@MyQualifier
	MyComponent wiredThird;

	@Test
	public void assertQualifierWiring() {

		assertThat(wiredFirst, is(first));
		assertThat(wiredSecond, is(second));
		assertThat(wiredThird, is(third));
	}
}