BAEL-3730: Add example of usage CacheManagerCustomizer in Spring Boot (#9048)

spring-caching/pom.xml

@@ -19,6 +19,10 @@
             <groupId>org.springframework</groupId>
             <artifactId>spring-context</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-cache</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-web</artifactId>

spring-caching/src/main/java/com/baeldung/caching/boot/CacheApplication.java

@@ -0,0 +1,14 @@
+package com.baeldung.caching.boot;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cache.annotation.EnableCaching;
+
+@SpringBootApplication
+@EnableCaching
+public class CacheApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(CacheApplication.class, args);
+    }
+}

spring-caching/src/main/java/com/baeldung/caching/boot/SimpleCacheCustomizer.java

@@ -0,0 +1,24 @@
+package com.baeldung.caching.boot;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.boot.autoconfigure.cache.CacheManagerCustomizer;
+import org.springframework.cache.concurrent.ConcurrentMapCacheManager;
+import org.springframework.stereotype.Component;
+
+import static java.util.Arrays.asList;
+
+@Component
+public class SimpleCacheCustomizer implements CacheManagerCustomizer<ConcurrentMapCacheManager> {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(SimpleCacheCustomizer.class);
+
+    static final String USERS_CACHE = "users";
+    static final String TRANSACTIONS_CACHE = "transactions";
+
+    @Override
+    public void customize(ConcurrentMapCacheManager cacheManager) {
+        LOGGER.info("Customizing Cache Manager");
+        cacheManager.setCacheNames(asList(USERS_CACHE, TRANSACTIONS_CACHE));
+    }
+}

spring-caching/src/test/java/com/baeldung/caching/boot/SimpleCacheCustomizerIntegrationTest.java

@@ -0,0 +1,24 @@
+package com.baeldung.caching.boot;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.cache.CacheManager;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class SimpleCacheCustomizerIntegrationTest {
+
+    @Autowired
+    private CacheManager cacheManager;
+
+    @Test
+    public void givenCacheManagerCustomizerWhenBootstrappedThenCacheManagerCustomized() {
+        assertThat(cacheManager.getCacheNames())
+          .containsOnly(SimpleCacheCustomizer.USERS_CACHE, SimpleCacheCustomizer.TRANSACTIONS_CACHE);
+    }
+}