Merge pull request #9227 from maciejglowka/BAEL-3829

BAEL-3829: example of dynamic bean autowiring in Spring

spring-core-4/src/main/java/com/baeldung/dynamic/autowire/BeanFactoryDynamicAutowireService.java

@@ -0,0 +1,27 @@
+package com.baeldung.dynamic.autowire;
+
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+@Service
+public class BeanFactoryDynamicAutowireService {
+    private static final String SERVICE_NAME_SUFFIX = "regionService";
+    private final BeanFactory beanFactory;
+
+    @Autowired
+    public BeanFactoryDynamicAutowireService(BeanFactory beanFactory) {
+        this.beanFactory = beanFactory;
+    }
+
+    public boolean isServerActive(String isoCountryCode, int serverId) {
+        RegionService service = beanFactory.getBean(getRegionServiceBeanName(isoCountryCode), RegionService.class);
+
+        return service.isServerActive(serverId);
+    }
+
+    private String getRegionServiceBeanName(String isoCountryCode) {
+        return isoCountryCode + SERVICE_NAME_SUFFIX;
+    }
+
+}

spring-core-4/src/main/java/com/baeldung/dynamic/autowire/CustomMapFromListDynamicAutowireService.java

@@ -0,0 +1,26 @@
+package com.baeldung.dynamic.autowire;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+@Service
+public class CustomMapFromListDynamicAutowireService {
+    private final Map<String, RegionService> servicesByCountryCode;
+
+    @Autowired
+    public CustomMapFromListDynamicAutowireService(List<RegionService> regionServices) {
+        servicesByCountryCode = regionServices.stream()
+                .collect(Collectors.toMap(RegionService::getISOCountryCode, Function.identity()));
+    }
+
+    public boolean isServerActive(String isoCountryCode, int serverId) {
+        RegionService service = servicesByCountryCode.get(isoCountryCode);
+
+        return service.isServerActive(serverId);
+    }
+}

spring-core-4/src/main/java/com/baeldung/dynamic/autowire/DynamicAutowireConfig.java

@@ -0,0 +1,9 @@
+package com.baeldung.dynamic.autowire;
+
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@ComponentScan("com.baeldung.dynamic.autowire")
+public class DynamicAutowireConfig {
+}

spring-core-4/src/main/java/com/baeldung/dynamic/autowire/GBRegionService.java

@@ -0,0 +1,16 @@
+package com.baeldung.dynamic.autowire;
+
+import org.springframework.stereotype.Service;
+
+@Service("GBregionService")
+public class GBRegionService implements RegionService {
+    @Override
+    public boolean isServerActive(int serverId) {
+        return false;
+    }
+
+    @Override
+    public String getISOCountryCode() {
+        return "GB";
+    }
+}

spring-core-4/src/main/java/com/baeldung/dynamic/autowire/RegionService.java

@@ -0,0 +1,7 @@
+package com.baeldung.dynamic.autowire;
+
+public interface RegionService {
+    boolean isServerActive(int serverId);
+
+    String getISOCountryCode();
+}

spring-core-4/src/main/java/com/baeldung/dynamic/autowire/USRegionService.java

@@ -0,0 +1,16 @@
+package com.baeldung.dynamic.autowire;
+
+import org.springframework.stereotype.Service;
+
+@Service("USregionService")
+public class USRegionService implements RegionService {
+    @Override
+    public boolean isServerActive(int serverId) {
+        return true;
+    }
+
+    @Override
+    public String getISOCountryCode() {
+        return "US";
+    }
+}

spring-core-4/src/test/java/com/baeldung/dynamic/autowire/DynamicAutowireIntegrationTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.dynamic.autowire;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = DynamicAutowireConfig.class)
+public class DynamicAutowireIntegrationTest {
+
+    @Autowired
+    private BeanFactoryDynamicAutowireService beanFactoryDynamicAutowireService;
+
+    @Autowired
+    private CustomMapFromListDynamicAutowireService customMapFromListDynamicAutowireService;
+
+    @Test
+    public void givenDynamicallyAutowiredBean_whenCheckingServerInGB_thenServerIsNotActive() {
+        assertThat(beanFactoryDynamicAutowireService.isServerActive("GB", 101), is(false));
+        assertThat(customMapFromListDynamicAutowireService.isServerActive("GB", 101), is(false));
+    }
+
+    @Test
+    public void givenDynamicallyAutowiredBean_whenCheckingServerInUS_thenServerIsActive() {
+        assertThat(beanFactoryDynamicAutowireService.isServerActive("US", 101), is(true));
+        assertThat(customMapFromListDynamicAutowireService.isServerActive("US", 101), is(true));
+    }
+}