Merge pull request #12 from eugenp/master

Getting latest changes
2019-01-11 22:52:54 -05:00
parent 2f12f1af7a 9e5b55889f
commit 09e14e6c0e
329 changed files with 5834 additions and 878 deletions
@@ -14,7 +14,7 @@ Java and Spring Tutorials
 ================

 This project is **a collection of small and focused tutorials** - each covering a single and well defined area of development in the Java ecosystem. 
-A strong focus of these is, of course, the Spring Framework - Spring, Spring Boot and Spring Securiyt. 
+A strong focus of these is, of course, the Spring Framework - Spring, Spring Boot and Spring Security. 
 In additional to Spring, the following technologies are in focus: `core Java`, `Jackson`, `HttpClient`, `Guava`. 


@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Introduction to Akka HTTP](https://www.baeldung.com/akka-http)
@@ -12,4 +12,6 @@
 - [Check If a String Contains All The Letters of The Alphabet](https://www.baeldung.com/java-string-contains-all-letters)
 - [Find the Middle Element of a Linked List](http://www.baeldung.com/java-linked-list-middle-element)
 - [Calculate Factorial in Java](https://www.baeldung.com/java-calculate-factorial)
- [Find Substrings That Are Palindromes in Java](https://www.baeldung.com/java-palindrome-substrings)
+- [Find Substrings That Are Palindromes in Java](https://www.baeldung.com/java-palindrome-substrings)
+- [Find the Longest Substring without Repeating Characters](https://www.baeldung.com/java-longest-substring-without-repeated-characters)
+- [Java Two Pointer Technique](https://www.baeldung.com/java-two-pointer-technique)
@@ -0,0 +1,123 @@
+package com.baeldung.algorithms.permutation;
+
+import java.util.Arrays;
+import java.util.Collections;
+
+public  class Permutation {
+
+    public static <T> void printAllRecursive(T[] elements, char delimiter) {
+        printAllRecursive(elements.length, elements, delimiter);
+    }
+
+    public static <T> void printAllRecursive(int n, T[] elements, char delimiter) {
+
+        if(n == 1) {
+            printArray(elements, delimiter);
+        } else {
+            for(int i = 0; i < n-1; i++) {
+                printAllRecursive(n - 1, elements, delimiter);
+                if(n % 2 == 0) {
+                    swap(elements, i, n-1);
+                } else {
+                    swap(elements, 0, n-1);
+                }
+            }
+            printAllRecursive(n - 1, elements, delimiter);
+        }
+    }
+
+    public static <T> void printAllIterative(int n, T[] elements, char delimiter) {
+
+        int[] indexes = new int[n];
+        for (int i = 0; i < n; i++) {
+            indexes[i] = 0;
+        }
+
+        printArray(elements, delimiter);
+
+        int i = 0;
+        while (i < n) {
+            if (indexes[i] < i) {
+                swap(elements, i % 2 == 0 ?  0: indexes[i], i);
+                printArray(elements, delimiter);
+                indexes[i]++;
+                i = 0;
+            }
+            else {
+                indexes[i] = 0;
+                i++;
+            }
+        }
+    }
+
+    public static <T extends Comparable<T>> void printAllOrdered(T[] elements, char delimiter) {
+
+        Arrays.sort(elements);
+        boolean hasNext = true;
+
+        while(hasNext) {
+            printArray(elements, delimiter);
+            int k = 0, l = 0;
+            hasNext = false;
+            for (int i = elements.length - 1; i > 0; i--) {
+                if (elements[i].compareTo(elements[i - 1]) > 0) {
+                    k = i - 1;
+                    hasNext = true;
+                    break;
+                }
+            }
+
+            for (int i = elements.length - 1; i > k; i--) {
+                if (elements[i].compareTo(elements[k]) > 0) {
+                    l = i;
+                    break;
+                }
+            }
+
+            swap(elements, k, l);
+            Collections.reverse(Arrays.asList(elements).subList(k + 1, elements.length));
+        }
+    }
+
+    public static <T> void printRandom(T[] elements, char delimiter) {
+
+        Collections.shuffle(Arrays.asList(elements));
+        printArray(elements, delimiter);
+    }
+
+    private static <T> void swap(T[] elements, int a, int b) {
+
+        T tmp = elements[a];
+        elements[a] = elements[b];
+        elements[b] = tmp;
+    }
+
+    private static <T> void printArray(T[] elements, char delimiter) {
+
+        String delimiterSpace = delimiter + " ";
+        for(int i = 0; i < elements.length; i++) {
+            System.out.print(elements[i] + delimiterSpace);
+        }
+        System.out.print('\n');
+    }
+
+    public static void main(String[] argv) {
+
+        Integer[] elements = {1,2,3,4};
+
+        System.out.println("Rec:");
+        printAllRecursive(elements, ';');
+
+        System.out.println("Iter:");
+        printAllIterative(elements.length, elements, ';');
+
+        System.out.println("Orderes:");
+        printAllOrdered(elements, ';');
+
+        System.out.println("Random:");
+        printRandom(elements, ';');
+
+        System.out.println("Random:");
+        printRandom(elements, ';');
+    }
+}
@@ -0,0 +1,16 @@
+package com.baeldung.algorithms.twopointertechnique;
+
+public class LinkedListFindMiddle {
+
+    public <T> T findMiddle(MyNode<T> head) {
+        MyNode<T> slowPointer = head;
+        MyNode<T> fastPointer = head;
+
+        while (fastPointer.next != null && fastPointer.next.next != null) {
+            fastPointer = fastPointer.next.next;
+            slowPointer = slowPointer.next;
+        }
+        return slowPointer.data;
+    }
+
+}
@@ -0,0 +1,20 @@
+package com.baeldung.algorithms.twopointertechnique;
+
+public class MyNode<E> {
+    MyNode<E> next;
+    E data;
+
+    public MyNode(E value) {
+        data = value;
+        next = null;
+    }
+
+    public MyNode(E value, MyNode<E> n) {
+        data = value;
+        next = n;
+    }
+
+    public void setNext(MyNode<E> n) {
+        next = n;
+    }
+}
@@ -0,0 +1,22 @@
+package com.baeldung.algorithms.twopointertechnique;
+
+public class RotateArray {
+
+    public void rotate(int[] input, int step) {
+        step %= input.length;
+        reverse(input, 0, input.length - 1);
+        reverse(input, 0, step - 1);
+        reverse(input, step, input.length - 1);
+    }
+
+    private void reverse(int[] input, int start, int end) {
+        while (start < end) {
+            int temp = input[start];
+            input[start] = input[end];
+            input[end] = temp;
+            start++;
+            end--;
+        }
+    }
+
+}
@@ -0,0 +1,38 @@
+package com.baeldung.algorithms.twopointertechnique;
+
+public class TwoSum {
+
+    public boolean twoSum(int[] input, int targetValue) {
+
+        int pointerOne = 0;
+        int pointerTwo = input.length - 1;
+
+        while (pointerOne < pointerTwo) {
+            int sum = input[pointerOne] + input[pointerTwo];
+
+            if (sum == targetValue) {
+                return true;
+            } else if (sum < targetValue) {
+                pointerOne++;
+            } else {
+                pointerTwo--;
+            }
+        }
+
+        return false;
+    }
+
+    public boolean twoSumSlow(int[] input, int targetValue) {
+
+        for (int i = 0; i < input.length; i++) {
+            for (int j = 1; j < input.length; j++) {
+                if (input[i] + input[j] == targetValue) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+}
@@ -0,0 +1,37 @@
+package com.baeldung.algorithms.twopointertechnique;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.Test;
+
+public class LinkedListFindMiddleUnitTest {
+
+    LinkedListFindMiddle linkedListFindMiddle = new LinkedListFindMiddle();
+
+    @Test
+    public void givenLinkedListOfMyNodes_whenLinkedListFindMiddle_thenCorrect() {
+
+        MyNode<String> head = createNodesList(8);
+
+        assertThat(linkedListFindMiddle.findMiddle(head)).isEqualTo("4");
+
+        head = createNodesList(9);
+
+        assertThat(linkedListFindMiddle.findMiddle(head)).isEqualTo("5");
+    }
+
+    private static MyNode<String> createNodesList(int n) {
+
+        MyNode<String> head = new MyNode<String>("1");
+        MyNode<String> current = head;
+
+        for (int i = 2; i <= n; i++) {
+            MyNode<String> newNode = new MyNode<String>(String.valueOf(i));
+            current.setNext(newNode);
+            current = newNode;
+        }
+
+        return head;
+    }
+
+}
@@ -0,0 +1,26 @@
+package com.baeldung.algorithms.twopointertechnique;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.Test;
+
+public class RotateArrayUnitTest {
+
+    private RotateArray rotateArray = new RotateArray();
+
+    private int[] inputArray;
+
+    private int step;
+
+    @Test
+    public void givenAnArrayOfIntegers_whenRotateKsteps_thenCorrect() {
+
+        inputArray = new int[] { 1, 2, 3, 4, 5, 6, 7 };
+        step = 4;
+
+        rotateArray.rotate(inputArray, step);
+
+        assertThat(inputArray).containsExactly(new int[] { 4, 5, 6, 7, 1, 2, 3 });
+    }
+
+}
@@ -0,0 +1,56 @@
+package com.baeldung.algorithms.twopointertechnique;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class TwoSumUnitTest {
+
+    private TwoSum twoSum = new TwoSum();
+
+    private int[] sortedArray;
+
+    private int targetValue;
+
+    @Test
+    public void givenASortedArrayOfIntegers_whenTwoSumSlow_thenPairExists() {
+
+        sortedArray = new int[] { 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9 };
+
+        targetValue = 12;
+
+        assertTrue(twoSum.twoSumSlow(sortedArray, targetValue));
+    }
+
+    @Test
+    public void givenASortedArrayOfIntegers_whenTwoSumSlow_thenPairDoesNotExists() {
+
+        sortedArray = new int[] { 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9 };
+
+        targetValue = 20;
+
+        assertFalse(twoSum.twoSumSlow(sortedArray, targetValue));
+    }
+
+    @Test
+    public void givenASortedArrayOfIntegers_whenTwoSum_thenPairExists() {
+
+        sortedArray = new int[] { 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9 };
+
+        targetValue = 12;
+
+        assertTrue(twoSum.twoSum(sortedArray, targetValue));
+    }
+
+    @Test
+    public void givenASortedArrayOfIntegers_whenTwoSum_thenPairDoesNotExists() {
+
+        sortedArray = new int[] { 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9 };
+
+        targetValue = 20;
+
+        assertFalse(twoSum.twoSum(sortedArray, targetValue));
+    }
+
+}
@@ -15,16 +15,76 @@
    </parent>

    <dependencies>
-        <!-- https://mvnrepository.com/artifact/org.apache.spark/spark-core_2.10 -->
        <dependency>
            <groupId>org.apache.spark</groupId>
-            <artifactId>spark-core_2.10</artifactId>
+            <artifactId>spark-core_2.11</artifactId>
            <version>${org.apache.spark.spark-core.version}</version>
+            <scope>provided</scope>
        </dependency>
+		<dependency>
+    		<groupId>org.apache.spark</groupId>
+    		<artifactId>spark-sql_2.11</artifactId>
+    		<version>${org.apache.spark.spark-sql.version}</version>
+    		<scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.spark</groupId>
+			<artifactId>spark-streaming_2.11</artifactId>
+			<version>${org.apache.spark.spark-streaming.version}</version>
+			<scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.spark</groupId>
+			<artifactId>spark-streaming-kafka-0-10_2.11</artifactId>
+			<version>${org.apache.spark.spark-streaming-kafka.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.datastax.spark</groupId>
+			<artifactId>spark-cassandra-connector_2.11</artifactId>
+			<version>${com.datastax.spark.spark-cassandra-connector.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.datastax.spark</groupId>
+			<artifactId>spark-cassandra-connector-java_2.11</artifactId>
+			<version>${com.datastax.spark.spark-cassandra-connector-java.version}</version>
+		</dependency>
    </dependencies>
-
+	<build>
+    	<plugins>
+    	  	<plugin>
+    			<groupId>org.apache.maven.plugins</groupId>
+    			<artifactId>maven-compiler-plugin</artifactId>
+    			<version>3.2</version>
+    			<configuration>
+      				<source>1.8</source>
+      				<target>1.8</target>
+    			</configuration>
+  			</plugin>
+      		<plugin>
+        		<artifactId>maven-assembly-plugin</artifactId>
+        		<executions>
+          			<execution>
+            			<phase>package</phase>
+            			<goals>
+              				<goal>single</goal>
+            			</goals>
+          			</execution>
+        		</executions>
+        		<configuration>
+          			<descriptorRefs>
+            			<descriptorRef>jar-with-dependencies</descriptorRef>
+          			</descriptorRefs>
+        		</configuration>
+      		</plugin>
+   		</plugins>
+  	</build>
    <properties>
-        <org.apache.spark.spark-core.version>2.2.0</org.apache.spark.spark-core.version>
+        <org.apache.spark.spark-core.version>2.3.0</org.apache.spark.spark-core.version>
+        <org.apache.spark.spark-sql.version>2.3.0</org.apache.spark.spark-sql.version>
+        <org.apache.spark.spark-streaming.version>2.3.0</org.apache.spark.spark-streaming.version>
+        <org.apache.spark.spark-streaming-kafka.version>2.3.0</org.apache.spark.spark-streaming-kafka.version>
+        <com.datastax.spark.spark-cassandra-connector.version>2.3.0</com.datastax.spark.spark-cassandra-connector.version>
+        <com.datastax.spark.spark-cassandra-connector-java.version>1.5.2</com.datastax.spark.spark-cassandra-connector-java.version>
    </properties>

 </project>
@@ -0,0 +1,25 @@
+package com.baeldung.data.pipeline;
+
+import java.io.Serializable;
+
+public class Word implements Serializable {
+    private static final long serialVersionUID = 1L;
+    private String word;
+    private int count;
+    Word(String word, int count) {
+        this.word = word;
+        this.count = count;
+    }
+    public String getWord() {
+        return word;
+    }
+    public void setWord(String word) {
+        this.word = word;
+    }
+    public int getCount() {
+        return count;
+    }
+    public void setCount(int count) {
+        this.count = count;
+    }
+}
@@ -0,0 +1,80 @@
+package com.baeldung.data.pipeline;
+
+import static com.datastax.spark.connector.japi.CassandraJavaUtil.javaFunctions;
+import static com.datastax.spark.connector.japi.CassandraJavaUtil.mapToRow;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.common.serialization.StringDeserializer;
+import org.apache.log4j.Level;
+import org.apache.log4j.Logger;
+import org.apache.spark.SparkConf;
+import org.apache.spark.api.java.JavaRDD;
+import org.apache.spark.streaming.Durations;
+import org.apache.spark.streaming.api.java.JavaDStream;
+import org.apache.spark.streaming.api.java.JavaInputDStream;
+import org.apache.spark.streaming.api.java.JavaPairDStream;
+import org.apache.spark.streaming.api.java.JavaStreamingContext;
+import org.apache.spark.streaming.kafka010.ConsumerStrategies;
+import org.apache.spark.streaming.kafka010.KafkaUtils;
+import org.apache.spark.streaming.kafka010.LocationStrategies;
+
+import scala.Tuple2;
+
+public class WordCountingApp {
+
+    public static void main(String[] args) throws InterruptedException {
+        Logger.getLogger("org")
+            .setLevel(Level.OFF);
+        Logger.getLogger("akka")
+            .setLevel(Level.OFF);
+
+        Map<String, Object> kafkaParams = new HashMap<>();
+        kafkaParams.put("bootstrap.servers", "localhost:9092");
+        kafkaParams.put("key.deserializer", StringDeserializer.class);
+        kafkaParams.put("value.deserializer", StringDeserializer.class);
+        kafkaParams.put("group.id", "use_a_separate_group_id_for_each_stream");
+        kafkaParams.put("auto.offset.reset", "latest");
+        kafkaParams.put("enable.auto.commit", false);
+
+        Collection<String> topics = Arrays.asList("messages");
+
+        SparkConf sparkConf = new SparkConf();
+        sparkConf.setMaster("local[2]");
+        sparkConf.setAppName("WordCountingApp");
+        sparkConf.set("spark.cassandra.connection.host", "127.0.0.1");
+
+        JavaStreamingContext streamingContext = new JavaStreamingContext(sparkConf, Durations.seconds(1));
+
+        JavaInputDStream<ConsumerRecord<String, String>> messages = KafkaUtils.createDirectStream(streamingContext, LocationStrategies.PreferConsistent(), ConsumerStrategies.<String, String> Subscribe(topics, kafkaParams));
+
+        JavaPairDStream<String, String> results = messages.mapToPair(record -> new Tuple2<>(record.key(), record.value()));
+
+        JavaDStream<String> lines = results.map(tuple2 -> tuple2._2());
+
+        JavaDStream<String> words = lines.flatMap(x -> Arrays.asList(x.split("\\s+"))
+            .iterator());
+
+        JavaPairDStream<String, Integer> wordCounts = words.mapToPair(s -> new Tuple2<>(s, 1))
+            .reduceByKey((i1, i2) -> i1 + i2);
+
+        wordCounts.foreachRDD(javaRdd -> {
+            Map<String, Integer> wordCountMap = javaRdd.collectAsMap();
+            for (String key : wordCountMap.keySet()) {
+                List<Word> wordList = Arrays.asList(new Word(key, wordCountMap.get(key)));
+                JavaRDD<Word> rdd = streamingContext.sparkContext()
+                    .parallelize(wordList);
+                javaFunctions(rdd).writerBuilder("vocabulary", "words", mapToRow(Word.class))
+                    .saveToCassandra();
+            }
+        });
+
+        streamingContext.start();
+        streamingContext.awaitTermination();
+    }
+}
@@ -0,0 +1,97 @@
+package com.baeldung.data.pipeline;
+
+import static com.datastax.spark.connector.japi.CassandraJavaUtil.javaFunctions;
+import static com.datastax.spark.connector.japi.CassandraJavaUtil.mapToRow;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.common.serialization.StringDeserializer;
+import org.apache.log4j.Level;
+import org.apache.log4j.Logger;
+import org.apache.spark.SparkConf;
+import org.apache.spark.api.java.JavaRDD;
+import org.apache.spark.api.java.JavaSparkContext;
+import org.apache.spark.api.java.function.Function2;
+import org.apache.spark.streaming.Durations;
+import org.apache.spark.streaming.StateSpec;
+import org.apache.spark.streaming.api.java.JavaDStream;
+import org.apache.spark.streaming.api.java.JavaInputDStream;
+import org.apache.spark.streaming.api.java.JavaMapWithStateDStream;
+import org.apache.spark.streaming.api.java.JavaPairDStream;
+import org.apache.spark.streaming.api.java.JavaStreamingContext;
+import org.apache.spark.streaming.kafka010.ConsumerStrategies;
+import org.apache.spark.streaming.kafka010.KafkaUtils;
+import org.apache.spark.streaming.kafka010.LocationStrategies;
+
+import scala.Tuple2;
+
+public class WordCountingAppWithCheckpoint {
+
+    public static JavaSparkContext sparkContext;
+
+    public static void main(String[] args) throws InterruptedException {
+
+        Logger.getLogger("org")
+            .setLevel(Level.OFF);
+        Logger.getLogger("akka")
+            .setLevel(Level.OFF);
+
+        Map<String, Object> kafkaParams = new HashMap<>();
+        kafkaParams.put("bootstrap.servers", "localhost:9092");
+        kafkaParams.put("key.deserializer", StringDeserializer.class);
+        kafkaParams.put("value.deserializer", StringDeserializer.class);
+        kafkaParams.put("group.id", "use_a_separate_group_id_for_each_stream");
+        kafkaParams.put("auto.offset.reset", "latest");
+        kafkaParams.put("enable.auto.commit", false);
+
+        Collection<String> topics = Arrays.asList("messages");
+
+        SparkConf sparkConf = new SparkConf();
+        sparkConf.setMaster("local[2]");
+        sparkConf.setAppName("WordCountingAppWithCheckpoint");
+        sparkConf.set("spark.cassandra.connection.host", "127.0.0.1");
+
+        JavaStreamingContext streamingContext = new JavaStreamingContext(sparkConf, Durations.seconds(1));
+
+        sparkContext = streamingContext.sparkContext();
+
+        streamingContext.checkpoint("./.checkpoint");
+
+        JavaInputDStream<ConsumerRecord<String, String>> messages = KafkaUtils.createDirectStream(streamingContext, LocationStrategies.PreferConsistent(), ConsumerStrategies.<String, String> Subscribe(topics, kafkaParams));
+
+        JavaPairDStream<String, String> results = messages.mapToPair(record -> new Tuple2<>(record.key(), record.value()));
+
+        JavaDStream<String> lines = results.map(tuple2 -> tuple2._2());
+
+        JavaDStream<String> words = lines.flatMap(x -> Arrays.asList(x.split("\\s+"))
+            .iterator());
+
+        JavaPairDStream<String, Integer> wordCounts = words.mapToPair(s -> new Tuple2<>(s, 1))
+            .reduceByKey((Function2<Integer, Integer, Integer>) (i1, i2) -> i1 + i2);
+
+        JavaMapWithStateDStream<String, Integer, Integer, Tuple2<String, Integer>> cumulativeWordCounts = wordCounts.mapWithState(StateSpec.function((word, one, state) -> {
+            int sum = one.orElse(0) + (state.exists() ? state.get() : 0);
+            Tuple2<String, Integer> output = new Tuple2<>(word, sum);
+            state.update(sum);
+            return output;
+        }));
+
+        cumulativeWordCounts.foreachRDD(javaRdd -> {
+            List<Tuple2<String, Integer>> wordCountList = javaRdd.collect();
+            for (Tuple2<String, Integer> tuple : wordCountList) {
+                List<Word> wordList = Arrays.asList(new Word(tuple._1, tuple._2));
+                JavaRDD<Word> rdd = sparkContext.parallelize(wordList);
+                javaFunctions(rdd).writerBuilder("vocabulary", "words", mapToRow(Word.class))
+                    .saveToCassandra();
+            }
+        });
+
+        streamingContext.start();
+        streamingContext.awaitTermination();
+    }
+}
@@ -4,29 +4,61 @@
    <modelVersion>4.0.0</modelVersion>
    <artifactId>axon</artifactId>
    <name>axon</name>
-        
+    <description>Basic Axon Framework with Spring Boot configuration tutorial</description>
+
    <parent>
-        <artifactId>parent-modules</artifactId>
        <groupId>com.baeldung</groupId>
-        <version>1.0.0-SNAPSHOT</version>
+        <artifactId>parent-boot-2</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-boot-2</relativePath>
    </parent>

    <dependencies>
+        <dependency>
+            <groupId>org.axonframework</groupId>
+            <artifactId>axon-spring-boot-starter</artifactId>
+            <version>${axon.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.axonframework</groupId>
+                    <artifactId>axon-server-connector</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+
        <dependency>
            <groupId>org.axonframework</groupId>
            <artifactId>axon-test</artifactId>
            <version>${axon.version}</version>
            <scope>test</scope>
        </dependency>
+
        <dependency>
-            <groupId>org.axonframework</groupId>
-            <artifactId>axon-core</artifactId>
-            <version>${axon.version}</version>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-autoconfigure</artifactId>
+            <version>2.1.1.RELEASE</version>
+            <scope>compile</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <scope>runtime</scope>
        </dependency>
    </dependencies>

    <properties>
-        <axon.version>3.0.2</axon.version>
+        <axon.version>4.0.3</axon.version>
    </properties>

 </project>
@@ -1,54 +0,0 @@
-package com.baeldung.axon;
-
-import com.baeldung.axon.aggregates.MessagesAggregate;
-import com.baeldung.axon.commands.CreateMessageCommand;
-import com.baeldung.axon.commands.MarkReadMessageCommand;
-import com.baeldung.axon.eventhandlers.MessagesEventHandler;
-import org.axonframework.commandhandling.AggregateAnnotationCommandHandler;
-import org.axonframework.commandhandling.CommandBus;
-import org.axonframework.commandhandling.SimpleCommandBus;
-import org.axonframework.commandhandling.gateway.CommandGateway;
-import org.axonframework.commandhandling.gateway.DefaultCommandGateway;
-import org.axonframework.eventhandling.AnnotationEventListenerAdapter;
-import org.axonframework.eventsourcing.EventSourcingRepository;
-import org.axonframework.eventsourcing.eventstore.EmbeddedEventStore;
-import org.axonframework.eventsourcing.eventstore.EventStore;
-import org.axonframework.eventsourcing.eventstore.inmemory.InMemoryEventStorageEngine;
-
-import java.util.UUID;
-
-public class MessagesRunner {
-
-    public static void main(String[] args) {
-        CommandBus commandBus = new SimpleCommandBus();
-
-        CommandGateway commandGateway = new DefaultCommandGateway(commandBus);
-
-        EventStore eventStore = new EmbeddedEventStore(new InMemoryEventStorageEngine());
-
-        EventSourcingRepository<MessagesAggregate> repository =
-                new EventSourcingRepository<>(MessagesAggregate.class, eventStore);
-
-
-        AggregateAnnotationCommandHandler<MessagesAggregate> messagesAggregateAggregateAnnotationCommandHandler =
-                new AggregateAnnotationCommandHandler<MessagesAggregate>(MessagesAggregate.class, repository);
-        messagesAggregateAggregateAnnotationCommandHandler.subscribe(commandBus);
-
-        final AnnotationEventListenerAdapter annotationEventListenerAdapter =
-                new AnnotationEventListenerAdapter(new MessagesEventHandler());
-        eventStore.subscribe(eventMessages -> eventMessages.forEach(e -> {
-                    try {
-                        annotationEventListenerAdapter.handle(e);
-                    } catch (Exception e1) {
-                        throw new RuntimeException(e1);
-
-                    }
-                }
-
-        ));
-
-        final String itemId = UUID.randomUUID().toString();
-        commandGateway.send(new CreateMessageCommand(itemId, "Hello, how is your day? :-)"));
-        commandGateway.send(new MarkReadMessageCommand(itemId));
-    }
-}
@@ -0,0 +1,13 @@
+package com.baeldung.axon;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class OrderApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(OrderApplication.class, args);
+    }
+
+}
@@ -1,36 +0,0 @@
-package com.baeldung.axon.aggregates;
-
-import com.baeldung.axon.commands.CreateMessageCommand;
-import com.baeldung.axon.commands.MarkReadMessageCommand;
-import com.baeldung.axon.events.MessageCreatedEvent;
-import com.baeldung.axon.events.MessageReadEvent;
-import org.axonframework.commandhandling.CommandHandler;
-import org.axonframework.commandhandling.model.AggregateIdentifier;
-import org.axonframework.eventhandling.EventHandler;
-
-import static org.axonframework.commandhandling.model.AggregateLifecycle.apply;
-
-
-public class MessagesAggregate {
-
-    @AggregateIdentifier
-    private String id;
-
-    public MessagesAggregate() {
-    }
-
-    @CommandHandler
-    public MessagesAggregate(CreateMessageCommand command) {
-        apply(new MessageCreatedEvent(command.getId(), command.getText()));
-    }
-
-    @EventHandler
-    public void on(MessageCreatedEvent event) {
-        this.id = event.getId();
-    }
-
-    @CommandHandler
-    public void markRead(MarkReadMessageCommand command) {
-        apply(new MessageReadEvent(id));
-    }
-}
@@ -0,0 +1,58 @@
+package com.baeldung.axon.commandmodel;
+
+import static org.axonframework.modelling.command.AggregateLifecycle.apply;
+
+import org.axonframework.commandhandling.CommandHandler;
+import org.axonframework.eventsourcing.EventSourcingHandler;
+import org.axonframework.modelling.command.AggregateIdentifier;
+import org.axonframework.spring.stereotype.Aggregate;
+
+import com.baeldung.axon.coreapi.commands.ConfirmOrderCommand;
+import com.baeldung.axon.coreapi.commands.PlaceOrderCommand;
+import com.baeldung.axon.coreapi.commands.ShipOrderCommand;
+import com.baeldung.axon.coreapi.events.OrderConfirmedEvent;
+import com.baeldung.axon.coreapi.events.OrderPlacedEvent;
+import com.baeldung.axon.coreapi.events.OrderShippedEvent;
+
+@Aggregate
+public class OrderAggregate {
+
+    @AggregateIdentifier
+    private String orderId;
+    private boolean orderConfirmed;
+
+    @CommandHandler
+    public OrderAggregate(PlaceOrderCommand command) {
+        apply(new OrderPlacedEvent(command.getOrderId(), command.getProduct()));
+    }
+
+    @CommandHandler
+    public void handle(ConfirmOrderCommand command) {
+        apply(new OrderConfirmedEvent(orderId));
+    }
+
+    @CommandHandler
+    public void handle(ShipOrderCommand command) {
+        if (!orderConfirmed) {
+            throw new IllegalStateException("Cannot ship an order which has not been confirmed yet.");
+        }
+
+        apply(new OrderShippedEvent(orderId));
+    }
+
+    @EventSourcingHandler
+    public void on(OrderPlacedEvent event) {
+        this.orderId = event.getOrderId();
+        orderConfirmed = false;
+    }
+
+    @EventSourcingHandler
+    public void on(OrderConfirmedEvent event) {
+        orderConfirmed = true;
+    }
+
+    protected OrderAggregate() {
+        // Required by Axon to build a default Aggregate prior to Event Sourcing
+    }
+
+}
@@ -1,24 +0,0 @@
-package com.baeldung.axon.commands;
-
-
-import org.axonframework.commandhandling.TargetAggregateIdentifier;
-
-public class CreateMessageCommand {
- 
-    @TargetAggregateIdentifier
-    private final String id;
-    private final String text;
- 
-    public CreateMessageCommand(String id, String text) {
-        this.id = id;
-        this.text = text;
-    }
- 
-    public String getId() {
-        return id;
-    }
- 
-    public String getText() {
-        return text;
-    }
-}
@@ -1,18 +0,0 @@
-package com.baeldung.axon.commands;
-
-
-import org.axonframework.commandhandling.TargetAggregateIdentifier;
-
-public class MarkReadMessageCommand {
- 
-    @TargetAggregateIdentifier
-    private final String id;
- 
-    public MarkReadMessageCommand(String id) {
-        this.id = id;
-    }
- 
-    public String getId() {
-        return id;
-    }
-}
@@ -0,0 +1,43 @@
+package com.baeldung.axon.coreapi.commands;
+
+import org.axonframework.modelling.command.TargetAggregateIdentifier;
+
+import java.util.Objects;
+
+public class ConfirmOrderCommand {
+
+    @TargetAggregateIdentifier
+    private final String orderId;
+
+    public ConfirmOrderCommand(String orderId) {
+        this.orderId = orderId;
+    }
+
+    public String getOrderId() {
+        return orderId;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(orderId);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final ConfirmOrderCommand other = (ConfirmOrderCommand) obj;
+        return Objects.equals(this.orderId, other.orderId);
+    }
+
+    @Override
+    public String toString() {
+        return "ConfirmOrderCommand{" +
+                "orderId='" + orderId + '\'' +
+                '}';
+    }
+}
@@ -0,0 +1,51 @@
+package com.baeldung.axon.coreapi.commands;
+
+import java.util.Objects;
+
+import org.axonframework.modelling.command.TargetAggregateIdentifier;
+
+public class PlaceOrderCommand {
+
+    @TargetAggregateIdentifier
+    private final String orderId;
+    private final String product;
+
+    public PlaceOrderCommand(String orderId, String product) {
+        this.orderId = orderId;
+        this.product = product;
+    }
+
+    public String getOrderId() {
+        return orderId;
+    }
+
+    public String getProduct() {
+        return product;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(orderId, product);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final PlaceOrderCommand other = (PlaceOrderCommand) obj;
+        return Objects.equals(this.orderId, other.orderId)
+                && Objects.equals(this.product, other.product);
+    }
+
+    @Override
+    public String toString() {
+        return "PlaceOrderCommand{" +
+                "orderId='" + orderId + '\'' +
+                ", product='" + product + '\'' +
+                '}';
+    }
+}
@@ -0,0 +1,43 @@
+package com.baeldung.axon.coreapi.commands;
+
+import java.util.Objects;
+
+import org.axonframework.modelling.command.TargetAggregateIdentifier;
+
+public class ShipOrderCommand {
+
+    @TargetAggregateIdentifier
+    private final String orderId;
+
+    public ShipOrderCommand(String orderId) {
+        this.orderId = orderId;
+    }
+
+    public String getOrderId() {
+        return orderId;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(orderId);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final ShipOrderCommand other = (ShipOrderCommand) obj;
+        return Objects.equals(this.orderId, other.orderId);
+    }
+
+    @Override
+    public String toString() {
+        return "ShipOrderCommand{" +
+                "orderId='" + orderId + '\'' +
+                '}';
+    }
+}
@@ -0,0 +1,40 @@
+package com.baeldung.axon.coreapi.events;
+
+import java.util.Objects;
+
+public class OrderConfirmedEvent {
+
+    private final String orderId;
+
+    public OrderConfirmedEvent(String orderId) {
+        this.orderId = orderId;
+    }
+
+    public String getOrderId() {
+        return orderId;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(orderId);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final OrderConfirmedEvent other = (OrderConfirmedEvent) obj;
+        return Objects.equals(this.orderId, other.orderId);
+    }
+
+    @Override
+    public String toString() {
+        return "OrderConfirmedEvent{" +
+                "orderId='" + orderId + '\'' +
+                '}';
+    }
+}
@@ -0,0 +1,48 @@
+package com.baeldung.axon.coreapi.events;
+
+import java.util.Objects;
+
+public class OrderPlacedEvent {
+
+    private final String orderId;
+    private final String product;
+
+    public OrderPlacedEvent(String orderId, String product) {
+        this.orderId = orderId;
+        this.product = product;
+    }
+
+    public String getOrderId() {
+        return orderId;
+    }
+
+    public String getProduct() {
+        return product;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(orderId, product);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final OrderPlacedEvent other = (OrderPlacedEvent) obj;
+        return Objects.equals(this.orderId, other.orderId)
+                && Objects.equals(this.product, other.product);
+    }
+
+    @Override
+    public String toString() {
+        return "OrderPlacedEvent{" +
+                "orderId='" + orderId + '\'' +
+                ", product='" + product + '\'' +
+                '}';
+    }
+}
@@ -0,0 +1,40 @@
+package com.baeldung.axon.coreapi.events;
+
+import java.util.Objects;
+
+public class OrderShippedEvent {
+
+    private final String orderId;
+
+    public OrderShippedEvent(String orderId) {
+        this.orderId = orderId;
+    }
+
+    public String getOrderId() {
+        return orderId;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(orderId);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final OrderShippedEvent other = (OrderShippedEvent) obj;
+        return Objects.equals(this.orderId, other.orderId);
+    }
+
+    @Override
+    public String toString() {
+        return "OrderShippedEvent{" +
+                "orderId='" + orderId + '\'' +
+                '}';
+    }
+}
@@ -0,0 +1,5 @@
+package com.baeldung.axon.coreapi.queries;
+
+public class FindAllOrderedProductsQuery {
+
+}
@@ -0,0 +1,7 @@
+package com.baeldung.axon.coreapi.queries;
+
+public enum OrderStatus {
+
+    PLACED, CONFIRMED, SHIPPED
+
+}
--- a/Show More
+++ b/Show More