New redis module

We have created this module to work with Redis Java libraries
Jedis tested so far

pom.xml

@@ -71,6 +71,7 @@
         <module>xml</module>
 
         <module>lombok</module>
+        <module>redis</module>
     </modules>
 
 </project>

redis/pom.xml

@@ -0,0 +1,41 @@
+<?xml version="1.0"?>
+<project
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>com.baeldung</groupId>
+	<artifactId>redis</artifactId>
+	<version>0.1-SNAPSHOT</version>
+
+	<name>redis</name>
+	<url>http://maven.apache.org</url>
+
+	<dependencies>
+		<dependency>
+			<groupId>redis.clients</groupId>
+			<artifactId>jedis</artifactId>
+			<version>2.8.1</version>
+		</dependency>
+
+		<dependency>
+			<groupId>com.github.kstyrc</groupId>
+			<artifactId>embedded-redis</artifactId>
+			<version>0.6</version>
+		</dependency>
+
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>${junit.version}</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+
+		<!-- testing -->
+		<junit.version>4.12</junit.version>
+	</properties>
+</project>

redis/src/test/java/com/baeldung/JedisTest.java

@@ -0,0 +1,225 @@
+package com.baeldung;
+
+import java.io.IOException;
+import java.time.Duration;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.JedisPool;
+import redis.clients.jedis.JedisPoolConfig;
+import redis.clients.jedis.Pipeline;
+import redis.clients.jedis.Response;
+import redis.clients.jedis.Transaction;
+import redis.embedded.RedisServer;
+
+/**
+ * Unit test for Redis Java library - Jedis.
+ */
+public class JedisTest {
+
+	private Jedis jedis;
+	private static RedisServer redisServer;
+
+	public JedisTest() {
+		jedis = new Jedis();
+	}
+	
+	@BeforeClass
+	public static void setUp() throws IOException {
+		redisServer = new RedisServer(6379);
+		redisServer.start();
+	}
+	
+	@AfterClass
+	public static void destroy() {
+		redisServer.stop();
+	}
+
+	@After
+	public void flush() {
+		jedis.flushAll();
+	}
+
+	@Test
+	public void givenAStringThenSaveItAsRedisStrings() {
+		String key = "key";
+		String value = "value";
+
+		jedis.set(key, value);
+		String value2 = jedis.get(key);
+
+		Assert.assertEquals(value, value2);
+	}
+
+	@Test
+	public void givenListElementsThenSaveThemInRedisList() {
+		String queue = "queue#tasks";
+
+		String taskOne = "firstTask";
+		String taskTwo = "secondTask";
+		String taskThree = "thirdTask";
+
+		jedis.lpush(queue, taskOne, taskTwo);
+
+		String taskReturnedOne = jedis.rpop(queue);
+
+		jedis.lpush(queue, taskThree);
+		Assert.assertEquals(taskOne, taskReturnedOne);
+
+		String taskReturnedTwo = jedis.rpop(queue);
+		String taskReturnedThree = jedis.rpop(queue);
+
+		Assert.assertEquals(taskTwo, taskReturnedTwo);
+		Assert.assertEquals(taskThree, taskReturnedThree);
+
+		String taskReturnedFour = jedis.rpop(queue);
+		Assert.assertNull(taskReturnedFour);
+	}
+
+	@Test
+	public void givenSetElementsThenSaveThemInRedisSet() {
+		String countries = "countries";
+
+		String countryOne = "Spain";
+		String countryTwo = "Ireland";
+		String countryThree = "Ireland";
+
+		jedis.sadd(countries, countryOne);
+
+		Set<String> countriesSet = jedis.smembers(countries);
+		Assert.assertEquals(1, countriesSet.size());
+
+		jedis.sadd(countries, countryTwo);
+		countriesSet = jedis.smembers(countries);
+		Assert.assertEquals(2, countriesSet.size());
+
+		jedis.sadd(countries, countryThree);
+		countriesSet = jedis.smembers(countries);
+		Assert.assertEquals(2, countriesSet.size());
+
+		boolean exists = jedis.sismember(countries, countryThree);
+		Assert.assertTrue(exists);
+	}
+
+	@Test
+	public void givenObjectFieldsThenSaveThemInRedisHash() {
+		String key = "user#1";
+
+		String field = "name";
+		String value = "William";
+
+		String field2 = "job";
+		String value2 = "politician";
+
+		jedis.hset(key, field, value);
+		jedis.hset(key, field2, value2);
+
+		String value3 = jedis.hget(key, field);
+		Assert.assertEquals(value, value3);
+
+		Map<String, String> fields = jedis.hgetAll(key);
+		String value4 = fields.get(field2);
+		Assert.assertEquals(value2, value4);
+	}
+
+	@Test
+	public void givenARankingThenSaveItInRedisSortedSet() {
+		String key = "ranking";
+
+		Map<String, Double> scores = new HashMap<>();
+
+		scores.put("PlayerOne", 3000.0);
+		scores.put("PlayerTwo", 1500.0);
+		scores.put("PlayerThree", 8200.0);
+
+		for (String player : scores.keySet()) {
+			jedis.zadd(key, scores.get(player), player);
+		}
+
+		Set<String> players = jedis.zrevrange(key, 0, 1);
+		Assert.assertEquals("PlayerThree", players.iterator().next());
+
+		long rank = jedis.zrevrank(key, "PlayerOne");
+		Assert.assertEquals(1, rank);
+	}
+
+	@Test
+	public void givenMultipleOperationsThatNeedToBeExecutedAtomicallyThenWrapThemInATransaction() {
+		String friendsPrefix = "friends#";
+
+		String userOneId = "4352523";
+		String userTwoId = "5552321";
+
+		Transaction t = jedis.multi();
+		t.sadd(friendsPrefix + userOneId, userTwoId);
+		t.sadd(friendsPrefix + userTwoId, userOneId);
+		t.exec();
+
+		boolean exists = jedis.sismember(friendsPrefix + userOneId, userTwoId);
+		Assert.assertTrue(exists);
+
+		exists = jedis.sismember(friendsPrefix + userTwoId, userOneId);
+		Assert.assertTrue(exists);
+	}
+
+	@Test
+	public void givenMultipleIndependentOperationsWhenNetworkOptimizationIsImportantThenWrapThemInAPipeline() {
+		String userOneId = "4352523";
+		String userTwoId = "4849888";
+
+		Pipeline p = jedis.pipelined();
+		p.sadd("searched#" + userOneId, "paris");
+		p.zadd("ranking", 126, userOneId);
+		p.zadd("ranking", 325, userTwoId);
+		Response<Boolean> pipeExists = p.sismember("searched#" + userOneId, "paris");
+		Response<Set<String>> pipeRanking = p.zrange("ranking", 0, -1);
+		p.sync();
+
+		Assert.assertTrue(pipeExists.get());
+		Assert.assertEquals(2, pipeRanking.get().size());
+	}
+	
+	@Test
+	public void givenAPoolConfigurationThenCreateAJedisPool() {
+		final JedisPoolConfig poolConfig = buildPoolConfig();
+		
+		try (JedisPool jedisPool = new JedisPool(poolConfig, "localhost"); 
+				Jedis jedis = jedisPool.getResource()) {
+			
+			// do simple operation to verify that the Jedis resource is working properly
+			String key = "key";
+			String value = "value";
+
+			jedis.set(key, value);
+			String value2 = jedis.get(key);
+
+			Assert.assertEquals(value, value2);
+			
+			// flush Redis
+			jedis.flushAll();
+		}
+	}
+	
+	private JedisPoolConfig buildPoolConfig() {
+        final JedisPoolConfig poolConfig = new JedisPoolConfig();
+        poolConfig.setMaxTotal(128);
+        poolConfig.setMaxIdle(128);
+        poolConfig.setMinIdle(16);
+        poolConfig.setTestOnBorrow(true);
+        poolConfig.setTestOnReturn(true);
+        poolConfig.setTestWhileIdle(true);
+        poolConfig.setMinEvictableIdleTimeMillis(Duration.ofSeconds(60).toMillis());
+        poolConfig.setTimeBetweenEvictionRunsMillis(Duration.ofSeconds(30).toMillis());
+        poolConfig.setNumTestsPerEvictionRun(3);
+        poolConfig.setBlockWhenExhausted(true);
+        return poolConfig;
+    }
+}