spring-boot ehcache example added (#6012)

pom.xml

@@ -663,6 +663,7 @@
                 <module>spring-dispatcher-servlet</module>
                 <module>spring-drools</module>
                 
+                <module>spring-ehcache</module>
                 <module>spring-ejb</module>
                 <module>spring-exceptions</module>
                 
@@ -882,6 +883,7 @@
 				<module>spring-data-rest</module>
 				<module>spring-dispatcher-servlet</module>
 				<module>spring-drools</module>
+				<module>spring-ehcache</module>
 				<module>spring-freemarker</module>
 				<module>persistence-modules/spring-hibernate-3</module>
 				<module>persistence-modules/spring-hibernate4</module>
@@ -1370,6 +1372,7 @@
                 <module>spring-dispatcher-servlet</module>
                 <module>spring-drools</module>
                 
+				<module>spring-ehcache</module>                
                 <module>spring-ejb</module>
                 <module>spring-exceptions</module>
                 

spring-ehcache/.gitignore

@@ -0,0 +1,13 @@
+*.class
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+
+# Packaged files #
+*.jar
+*.war
+*.ear

spring-ehcache/README.md

@@ -0,0 +1,7 @@
+## Spring Ehcache Example Project
+
+A simple example of using ehcache with spring-boot.
+
+### Relevant Articles:
+- [Spring Boot Ehcache Example](http://www.baeldung.com/spring-ehcache)
+

spring-ehcache/checkstyle.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE module PUBLIC
+          "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
+          "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
+<module name="Checker">
+	<module name="TreeWalker">
+		<module name="AvoidStarImport">
+			<property name="severity" value="warning" />
+		</module>
+	</module>
+</module>

spring-ehcache/pom.xml

@@ -0,0 +1,87 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>spring-ehcache</artifactId>
+    <version>0.1-SNAPSHOT</version>
+    <name>spring-ehcache</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <artifactId>parent-boot-2</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-boot-2</relativePath>
+    </parent>
+
+    <dependencies>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-cache</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>javax.cache</groupId>
+            <artifactId>cache-api</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.ehcache</groupId>
+            <artifactId>ehcache</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>spring-ehcache</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-checkstyle-plugin</artifactId>
+                <version>${checkstyle-maven-plugin.version}</version>
+                <configuration>
+                    <configLocation>checkstyle.xml</configLocation>
+                </configuration>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <reporting>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-checkstyle-plugin</artifactId>
+                <version>${checkstyle-maven-plugin.version}</version>
+                <configuration>
+                    <configLocation>checkstyle.xml</configLocation>
+                </configuration>
+            </plugin>
+        </plugins>
+    </reporting>
+
+    <properties>
+        <!-- Maven plugins -->
+        <checkstyle-maven-plugin.version>3.0.0</checkstyle-maven-plugin.version>
+        <dependency.locations.enabled>false</dependency.locations.enabled>
+    </properties>
+
+</project>

spring-ehcache/src/main/java/com/baeldung/cachetest/Application.java

@@ -0,0 +1,13 @@
+package com.baeldung.cachetest;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Application {
+
+	public static void main(String[] args) {
+		SpringApplication.run(Application.class, args);
+	}
+
+}

spring-ehcache/src/main/java/com/baeldung/cachetest/config/CacheConfig.java

@@ -0,0 +1,57 @@
+package com.baeldung.cachetest.config;
+
+import java.math.BigDecimal;
+import java.time.Duration;
+
+import javax.cache.CacheManager;
+
+import org.ehcache.config.CacheConfiguration;
+import org.ehcache.config.ResourcePools;
+import org.ehcache.config.builders.CacheConfigurationBuilder;
+import org.ehcache.config.builders.CacheEventListenerConfigurationBuilder;
+import org.ehcache.config.builders.ExpiryPolicyBuilder;
+import org.ehcache.config.builders.ResourcePoolsBuilder;
+import org.ehcache.config.units.EntryUnit;
+import org.ehcache.config.units.MemoryUnit;
+import org.ehcache.event.EventType;
+import org.ehcache.jsr107.Eh107Configuration;
+import org.springframework.boot.autoconfigure.cache.JCacheManagerCustomizer;
+import org.springframework.cache.annotation.EnableCaching;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@EnableCaching
+public class CacheConfig {
+
+	private static final int ON_HEAP_CACHE_SIZE_ENTRIES = 2;
+	private static final int OFF_HEAP_CACHE_SIZE_MB = 10;
+	private static final int CACHE_EXPIRY_SECONDS = 30;
+
+	@Bean
+	public JCacheManagerCustomizer jcacheManagerCustomizer() {
+		return new JCacheManagerCustomizer() {
+
+			@Override
+			public void customize(CacheManager cacheManager) {
+				ResourcePools resourcePools = ResourcePoolsBuilder.newResourcePoolsBuilder()
+						.heap(ON_HEAP_CACHE_SIZE_ENTRIES, EntryUnit.ENTRIES)
+						.offheap(OFF_HEAP_CACHE_SIZE_MB, MemoryUnit.MB).build();
+
+				CacheEventListenerConfigurationBuilder eventLoggerConfig = CacheEventListenerConfigurationBuilder
+						.newEventListenerConfiguration(new CacheEventLogger(), EventType.CREATED, EventType.EXPIRED)
+						.unordered().asynchronous();
+
+				CacheConfiguration<?, ?> cacheConfiguration = CacheConfigurationBuilder
+						.newCacheConfigurationBuilder(Long.class, BigDecimal.class, resourcePools)
+						.withExpiry(ExpiryPolicyBuilder.timeToLiveExpiration(Duration.ofSeconds(CACHE_EXPIRY_SECONDS)))
+						.add(eventLoggerConfig).build();
+
+				cacheManager.createCache("squareCache",
+						Eh107Configuration.fromEhcacheCacheConfiguration(cacheConfiguration));
+
+			}
+		};
+	}
+
+}

spring-ehcache/src/main/java/com/baeldung/cachetest/config/CacheEventLogger.java

@@ -0,0 +1,18 @@
+package com.baeldung.cachetest.config;
+
+import org.ehcache.event.CacheEvent;
+import org.ehcache.event.CacheEventListener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class CacheEventLogger implements CacheEventListener<Object, Object> {
+
+	private static final Logger log = LoggerFactory.getLogger(CacheEventLogger.class);
+
+	@Override
+	public void onEvent(CacheEvent<? extends Object, ? extends Object> cacheEvent) {
+		log.info("Cache event {} for item with key {}. Old value = {}, New value = {}", cacheEvent.getType(),
+				cacheEvent.getKey(), cacheEvent.getOldValue(), cacheEvent.getNewValue());
+	}
+
+}

spring-ehcache/src/main/java/com/baeldung/cachetest/rest/NumberController.java

@@ -0,0 +1,29 @@
+package com.baeldung.cachetest.rest;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.MediaType;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.cachetest.service.NumberService;
+
+@RestController
+@RequestMapping(path = "/number", produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
+public class NumberController {
+
+	private final static Logger log = LoggerFactory.getLogger(NumberController.class);
+
+	@Autowired
+	private NumberService numberService;
+
+	@GetMapping(path = "/square/{number}")
+	public String getThing(@PathVariable Long number) {
+		log.info("call numberService to square {}", number);
+		return String.format("{\"square\": %s}", numberService.square(number));
+	}
+
+}

spring-ehcache/src/main/java/com/baeldung/cachetest/service/NumberService.java

@@ -0,0 +1,22 @@
+package com.baeldung.cachetest.service;
+
+import java.math.BigDecimal;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.cache.annotation.Cacheable;
+import org.springframework.stereotype.Service;
+
+@Service
+public class NumberService {
+
+	private final static Logger log = LoggerFactory.getLogger(NumberService.class);
+
+	@Cacheable(value = "squareCache", key = "#number", condition = "#number>10")
+	public BigDecimal square(Long number) {
+		BigDecimal square = BigDecimal.valueOf(number).multiply(BigDecimal.valueOf(number));
+		log.info("square of {} is {}", number, square);
+		return square;
+	}
+
+}