Merge branch 'master' into sla-pr/1272-testng

2017-03-01 22:20:59 +01:00
parent d1f0b2e554 6590e02bd4
commit 95e24dac2a
289 changed files with 10284 additions and 230 deletions
@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [A Guide to JGit](http://www.baeldung.com/jgit)
@@ -0,0 +1,4 @@
+## Relevant articles:
+
+- [Dijkstra Algorithm in Java](http://www.baeldung.com/java-dijkstra)
+- [Introduction to Cobertura](http://www.baeldung.com/cobertura)
@@ -41,4 +41,23 @@
 			</plugins>
 		</pluginManagement>
 	</build>
-</project>
+	<reporting>
+		<plugins>
+			<plugin>
+				<groupId>org.codehaus.mojo</groupId>
+				<artifactId>cobertura-maven-plugin</artifactId>
+				<version>2.7</version>
+				<configuration>
+					<instrumentation>
+						<ignores>
+							<ignore>com/baeldung/algorithms/dijkstra/*</ignore>
+						</ignores>
+						<excludes>
+							<exclude>com/baeldung/algorithms/dijkstra/*</exclude>
+						</excludes>
+					</instrumentation>
+				</configuration>
+			</plugin>
+		</plugins>
+	</reporting>
+</project>
@@ -0,0 +1,2 @@
+### Relevant Articles:
+- [Intro to Apache BVal](http://www.baeldung.com/apache-bval)
@@ -0,0 +1,50 @@
+<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>
+	<groupId>com.baeldung</groupId>
+	<artifactId>apache-solrj</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <name>apache-solrj</name>
+
+	<properties>
+		<junit.version>4.12</junit.version>
+		<maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.apache.solr</groupId>
+			<artifactId>solr-solrj</artifactId>
+			<version>6.4.0</version>
+		</dependency>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>${junit.version}</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>2.3.2</version>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<version>${maven-surefire-plugin.version}</version>
+				<configuration>
+					<source>1.8</source>
+					<target>1.8</target>
+					<excludes>
+						<exclude>**/*IntegrationTest.java</exclude>
+						<exclude>**/*LiveTest.java</exclude>
+					</excludes>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+</project>
@@ -0,0 +1,44 @@
+package com.baeldung.solrjava;
+
+import org.apache.solr.client.solrj.beans.Field;
+
+public class ProductBean {
+
+    String id;
+    String name;
+    String price;
+
+    public ProductBean(String id, String name, String price) {
+        super();
+        this.id = id;
+        this.name = name;
+        this.price = price;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    @Field("id")
+    protected void setId(String id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    @Field("name")
+    protected void setName(String name) {
+        this.name = name;
+    }
+
+    public String getPrice() {
+        return price;
+    }
+
+    @Field("price")
+    protected void setPrice(String price) {
+        this.price = price;
+    }
+}
@@ -0,0 +1,56 @@
+package com.baeldung.solrjava;
+
+import java.io.IOException;
+
+import org.apache.solr.client.solrj.SolrServerException;
+import org.apache.solr.client.solrj.impl.HttpSolrClient;
+import org.apache.solr.client.solrj.impl.XMLResponseParser;
+import org.apache.solr.common.SolrInputDocument;
+
+public class SolrJavaIntegration {
+
+    private HttpSolrClient solrClient;
+
+    public SolrJavaIntegration(String clientUrl) {
+
+        solrClient = new HttpSolrClient.Builder(clientUrl).build();
+        solrClient.setParser(new XMLResponseParser());
+    }
+
+    public void addProductBean(ProductBean pBean) throws IOException, SolrServerException {
+
+        solrClient.addBean(pBean);
+        solrClient.commit();
+    }
+
+    public void addSolrDocument(String documentId, String itemName, String itemPrice) throws SolrServerException, IOException {
+
+        SolrInputDocument document = new SolrInputDocument();
+        document.addField("id", documentId);
+        document.addField("name", itemName);
+        document.addField("price", itemPrice);
+        solrClient.add(document);
+        solrClient.commit();
+    }
+
+    public void deleteSolrDocumentById(String documentId) throws SolrServerException, IOException {
+
+        solrClient.deleteById(documentId);
+        solrClient.commit();
+    }
+
+    public void deleteSolrDocumentByQuery(String query) throws SolrServerException, IOException {
+
+        solrClient.deleteByQuery(query);
+        solrClient.commit();
+    }
+
+    protected HttpSolrClient getSolrClient() {
+        return solrClient;
+    }
+
+    protected void setSolrClient(HttpSolrClient solrClient) {
+        this.solrClient = solrClient;
+    }
+
+}
@@ -0,0 +1,108 @@
+package com.baeldung.solrjava;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+
+import org.apache.solr.client.solrj.SolrQuery;
+import org.apache.solr.client.solrj.SolrServerException;
+import org.apache.solr.client.solrj.response.QueryResponse;
+import org.apache.solr.common.SolrDocument;
+import org.apache.solr.common.SolrDocumentList;
+import org.junit.Before;
+import org.junit.Test;
+
+public class SolrJavaIntegrationTest {
+
+    private SolrJavaIntegration solrJavaIntegration;
+
+    @Before
+    public void setUp() throws Exception {
+
+        solrJavaIntegration = new SolrJavaIntegration("http://localhost:8983/solr/bigboxstore");
+        solrJavaIntegration.addSolrDocument("123456", "Kenmore Dishwasher", "599.99");
+    }
+
+    @Test
+    public void whenAdd_thenVerifyAddedByQueryOnId() throws SolrServerException, IOException {
+
+        SolrQuery query = new SolrQuery();
+        query.set("q", "id:123456");
+        QueryResponse response = null;
+
+        response = solrJavaIntegration.getSolrClient().query(query);
+
+        SolrDocumentList docList = response.getResults();
+        assertEquals(docList.getNumFound(), 1);
+
+        for (SolrDocument doc : docList) {
+            assertEquals("Kenmore Dishwasher", (String) doc.getFieldValue("name"));
+            assertEquals((Double) 599.99, (Double) doc.getFieldValue("price"));
+        }
+    }
+
+    @Test
+    public void whenAdd_thenVerifyAddedByQueryOnPrice() throws SolrServerException, IOException {
+
+        SolrQuery query = new SolrQuery();
+        query.set("q", "price:599.99");
+        QueryResponse response = null;
+
+        response = solrJavaIntegration.getSolrClient().query(query);
+
+        SolrDocumentList docList = response.getResults();
+        assertEquals(1, docList.getNumFound());
+
+        for (SolrDocument doc : docList) {
+            assertEquals("123456", (String) doc.getFieldValue("id"));
+            assertEquals((Double) 599.99, (Double) doc.getFieldValue("price"));
+        }
+    }
+
+    @Test
+    public void whenAdd_thenVerifyAddedByQuery() throws SolrServerException, IOException {
+
+        SolrDocument doc = solrJavaIntegration.getSolrClient().getById("123456");
+        assertEquals("Kenmore Dishwasher", (String) doc.getFieldValue("name"));
+        assertEquals((Double) 599.99, (Double) doc.getFieldValue("price"));
+    }
+
+    @Test
+    public void whenAddBean_thenVerifyAddedByQuery() throws SolrServerException, IOException {
+
+        ProductBean pBean = new ProductBean("888", "Apple iPhone 6s", "299.99");
+        solrJavaIntegration.addProductBean(pBean);
+
+        SolrDocument doc = solrJavaIntegration.getSolrClient().getById("888");
+        assertEquals("Apple iPhone 6s", (String) doc.getFieldValue("name"));
+        assertEquals((Double) 299.99, (Double) doc.getFieldValue("price"));
+    }
+
+    @Test
+    public void whenDeleteById_thenVerifyDeleted() throws SolrServerException, IOException {
+
+        solrJavaIntegration.deleteSolrDocumentById("123456");
+
+        SolrQuery query = new SolrQuery();
+        query.set("q", "id:123456");
+        QueryResponse response = solrJavaIntegration.getSolrClient().query(query);
+
+        SolrDocumentList docList = response.getResults();
+        assertEquals(0, docList.getNumFound());
+    }
+
+    @Test
+    public void whenDeleteByQuery_thenVerifyDeleted() throws SolrServerException, IOException {
+
+        solrJavaIntegration.deleteSolrDocumentByQuery("name:Kenmore Dishwasher");
+
+        SolrQuery query = new SolrQuery();
+        query.set("q", "id:123456");
+        QueryResponse response = null;
+
+        response = solrJavaIntegration.getSolrClient().query(query);
+
+        SolrDocumentList docList = response.getResults();
+        assertEquals(0, docList.getNumFound());
+    }
+}
@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Working with Apache Thrift](http://www.baeldung.com/apache-thrift)
@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Introduction to Apache Velocity](http://www.baeldung.com/apache-velocity)
@@ -7,17 +7,36 @@
 	<packaging>jar</packaging>
 	<name>aws</name>

+	<properties>
+		<commons-io.version>2.5</commons-io.version>
+		<aws-lambda-java-events.version>1.3.0</aws-lambda-java-events.version>
+		<aws-lambda-java-core.version>1.1.0</aws-lambda-java-core.version>
+		<gson.version>2.8.0</gson.version>
+	</properties>
+
 	<dependencies>
 		<dependency>
 			<groupId>com.amazonaws</groupId>
 			<artifactId>aws-lambda-java-core</artifactId>
-			<version>1.1.0</version>
+			<version>${aws-lambda-java-core.version}</version>
+		</dependency>
+
+		<dependency>
+			<groupId>com.amazonaws</groupId>
+			<artifactId>aws-lambda-java-events</artifactId>
+			<version>${aws-lambda-java-events.version}</version>
 		</dependency>

 		<dependency>
 			<groupId>commons-io</groupId>
 			<artifactId>commons-io</artifactId>
-			<version>2.5</version>
+			<version>${commons-io.version}</version>
+		</dependency>
+
+		<dependency>
+			<groupId>com.google.code.gson</groupId>
+			<artifactId>gson</artifactId>
+			<version>${gson.version}</version>
 		</dependency>
 	</dependencies>

@@ -26,7 +45,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-shade-plugin</artifactId>
-				<version>2.3</version>
+				<version>3.0.0</version>
 				<configuration>
 					<createDependencyReducedPom>false</createDependencyReducedPom>
 				</configuration>
@@ -0,0 +1,49 @@
+package com.baeldung.lambda.dynamodb;
+
+import com.amazonaws.regions.Region;
+import com.amazonaws.regions.Regions;
+import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient;
+import com.amazonaws.services.dynamodbv2.document.DynamoDB;
+import com.amazonaws.services.dynamodbv2.document.Item;
+import com.amazonaws.services.dynamodbv2.document.PutItemOutcome;
+import com.amazonaws.services.dynamodbv2.document.spec.PutItemSpec;
+import com.amazonaws.services.dynamodbv2.model.ConditionalCheckFailedException;
+import com.amazonaws.services.lambda.runtime.Context;
+import com.amazonaws.services.lambda.runtime.RequestHandler;
+import com.baeldung.lambda.dynamodb.bean.PersonRequest;
+import com.baeldung.lambda.dynamodb.bean.PersonResponse;
+
+public class SavePersonHandler implements RequestHandler<PersonRequest, PersonResponse> {
+
+    private DynamoDB dynamoDb;
+
+    private String DYNAMODB_TABLE_NAME = "Person";
+    private Regions REGION = Regions.US_WEST_2;
+
+    public PersonResponse handleRequest(PersonRequest personRequest, Context context) {
+        this.initDynamoDbClient();
+
+        persistData(personRequest);
+
+        PersonResponse personResponse = new PersonResponse();
+        personResponse.setMessage("Saved Successfully!!!");
+        return personResponse;
+    }
+
+    private PutItemOutcome persistData(PersonRequest personRequest) throws ConditionalCheckFailedException {
+        return this.dynamoDb.getTable(DYNAMODB_TABLE_NAME)
+          .putItem(
+            new PutItemSpec().withItem(new Item()
+              .withNumber("id", personRequest.getId())
+              .withString("firstName", personRequest.getFirstName())
+              .withString("lastName", personRequest.getLastName())
+              .withNumber("age", personRequest.getAge())
+              .withString("address", personRequest.getAddress())));
+    }
+
+    private void initDynamoDbClient() {
+        AmazonDynamoDBClient client = new AmazonDynamoDBClient();
+        client.setRegion(Region.getRegion(REGION));
+        this.dynamoDb = new DynamoDB(client);
+    }
+}
@@ -0,0 +1,67 @@
+package com.baeldung.lambda.dynamodb.bean;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+
+public class PersonRequest {
+    private int id;
+    private String firstName;
+    private String lastName;
+    private int age;
+    private String address;
+
+    public static void main(String[] args) {
+        PersonRequest personRequest = new PersonRequest();
+        personRequest.setId(1);
+        personRequest.setFirstName("John");
+        personRequest.setLastName("Doe");
+        personRequest.setAge(30);
+        personRequest.setAddress("United States");
+        System.out.println(personRequest);
+    }
+
+    public String toString() {
+        final Gson gson = new GsonBuilder().setPrettyPrinting().create();
+        return gson.toJson(this);
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+}
@@ -0,0 +1,20 @@
+package com.baeldung.lambda.dynamodb.bean;
+
+import com.google.gson.Gson;
+
+public class PersonResponse {
+    private String message;
+
+    public String toString() {
+        final Gson gson = new Gson();
+        return gson.toJson(this);
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+}
@@ -6,3 +6,5 @@

 ### Relevant Articles:
 - [Java 9 Stream API Improvements](http://www.baeldung.com/java-9-stream-api)
+- [Java 9 Convenience Factory Methods for Collections](http://www.baeldung.com/java-9-collections-factory-methods) 
+- [New Stream Collectors in Java 9](http://www.baeldung.com/java9-stream-collectors)
@@ -21,6 +21,11 @@
            <artifactId>slf4j-api</artifactId>
            <version>${org.slf4j.version}</version>
        </dependency>
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>${ch.qos.logback.version}</version>
+        </dependency>

        <dependency>
            <groupId>org.hamcrest</groupId>
@@ -76,9 +81,9 @@
    
        <!-- logging -->
        <org.slf4j.version>1.7.21</org.slf4j.version>
-
+        <ch.qos.logback.version>1.2.1</ch.qos.logback.version>
        <!-- maven plugins -->
-        <maven-compiler-plugin.version>3.6-jigsaw-SNAPSHOT</maven-compiler-plugin.version>
+        <maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
        <maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>

        <!-- testing -->
@@ -0,0 +1,133 @@
+package com.baeldung.java9.process;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Stream;
+
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Created by sanaulla on 2/23/2017.
+ */
+
+public class ProcessAPIEnhancementsTest {
+
+    Logger log = LoggerFactory.getLogger(ProcessAPIEnhancementsTest.class);
+
+    @Test
+    public void givenCurrentProcess_whenInvokeGetInfo_thenSuccess() throws IOException {
+        ProcessHandle processHandle = ProcessHandle.current();
+        ProcessHandle.Info processInfo = processHandle.info();
+        assertNotNull(processHandle.getPid());
+        assertEquals(false, processInfo.arguments()
+          .isPresent());
+        assertEquals(true, processInfo.command()
+          .isPresent());
+        assertTrue(processInfo.command()
+          .get()
+          .contains("java"));
+
+        assertEquals(true, processInfo.startInstant()
+          .isPresent());
+        assertEquals(true, processInfo.totalCpuDuration()
+          .isPresent());
+        assertEquals(true, processInfo.user()
+          .isPresent());
+    }
+
+    @Test
+    public void givenSpawnProcess_whenInvokeGetInfo_thenSuccess() throws IOException {
+
+        String javaCmd = ProcessUtils.getJavaCmd()
+          .getAbsolutePath();
+        ProcessBuilder processBuilder = new ProcessBuilder(javaCmd, "-version");
+        Process process = processBuilder.inheritIO()
+          .start();
+        ProcessHandle processHandle = process.toHandle();
+        ProcessHandle.Info processInfo = processHandle.info();
+        assertNotNull(processHandle.getPid());
+        assertEquals(false, processInfo.arguments()
+          .isPresent());
+        assertEquals(true, processInfo.command()
+          .isPresent());
+        assertTrue(processInfo.command()
+          .get()
+          .contains("java"));
+        assertEquals(true, processInfo.startInstant()
+          .isPresent());
+        assertEquals(true, processInfo.totalCpuDuration()
+          .isPresent());
+        assertEquals(true, processInfo.user()
+          .isPresent());
+    }
+
+    @Test
+    public void givenLiveProcesses_whenInvokeGetInfo_thenSuccess() {
+        Stream<ProcessHandle> liveProcesses = ProcessHandle.allProcesses();
+        liveProcesses.filter(ProcessHandle::isAlive)
+            .forEach(ph -> {
+                assertNotNull(ph.getPid());
+                assertEquals(true, ph.info()
+                  .command()
+                  .isPresent());
+                assertEquals(true, ph.info()
+                  .startInstant()
+                  .isPresent());
+                assertEquals(true, ph.info()
+                  .totalCpuDuration()
+                  .isPresent());
+                assertEquals(true, ph.info()
+                  .user()
+                  .isPresent());
+            });
+    }
+
+    @Test
+    public void givenProcess_whenGetChildProcess_thenSuccess() throws IOException {
+        int childProcessCount = 5;
+        for (int i = 0; i < childProcessCount; i++) {
+            String javaCmd = ProcessUtils.getJavaCmd()
+              .getAbsolutePath();
+            ProcessBuilder processBuilder
+              = new ProcessBuilder(javaCmd, "-version");
+            processBuilder.inheritIO().start();
+        }
+
+        Stream<ProcessHandle> children = ProcessHandle.current()
+          .children();
+        children.filter(ProcessHandle::isAlive)
+          .forEach(ph -> log.info("PID: {}, Cmd: {}", ph.getPid(), ph.info()
+            .command()));
+        Stream<ProcessHandle> descendants = ProcessHandle.current()
+          .descendants();
+        descendants.filter(ProcessHandle::isAlive)
+          .forEach(ph -> log.info("PID: {}, Cmd: {}", ph.getPid(), ph.info()
+            .command()));
+    }
+
+    @Test
+    public void givenProcess_whenAddExitCallback_thenSuccess() throws Exception {
+        String javaCmd = ProcessUtils.getJavaCmd()
+          .getAbsolutePath();
+        ProcessBuilder processBuilder
+          = new ProcessBuilder(javaCmd, "-version");
+        Process process = processBuilder.inheritIO()
+          .start();
+        ProcessHandle processHandle = process.toHandle();
+
+        log.info("PID: {} has started", processHandle.getPid());
+        CompletableFuture<ProcessHandle> onProcessExit = processHandle.onExit();
+        onProcessExit.get();
+        assertEquals(false, processHandle.isAlive());
+        onProcessExit.thenAccept(ph -> {
+            log.info("PID: {} has stopped", ph.getPid());
+        });
+    }
+
+}
@@ -58,3 +58,24 @@
 - [Guide to java.util.concurrent.BlockingQueue](http://www.baeldung.com/java-blocking-queue)
 - [Guide to CountDownLatch in Java](http://www.baeldung.com/java-countdown-latch)
 - [How to Design a Genetic Algorithm in Java](http://www.baeldung.com/java-genetic-algorithm)
+- [A Guide to ConcurrentMap](http://www.baeldung.com/java-concurrent-map)
+- [Guide to PriorityBlockingQueue in Java](http://www.baeldung.com/java-priority-blocking-queue)
+- [Guide to Java 8 groupingBy Collector](http://www.baeldung.com/java-groupingby-collector)
+- [Avoiding the ConcurrentModificationException in Java](http://www.baeldung.com/java-concurrentmodificationexception)
+- [Guide to WeakHashMap in Java](http://www.baeldung.com/java-weakhashmap)
+- [Strategy Design Pattern in Java 8](http://www.baeldung.com/java-strategy-pattern)
+- [Java 8 and Infinite Streams](http://www.baeldung.com/java-inifinite-streams)
+- [Custom Thread Pools In Java 8 Parallel Streams](http://www.baeldung.com/java-8-parallel-streams-custom-threadpool)
+- [String Operations with Java Streams](http://www.baeldung.com/java-stream-operations-on-strings)
+- [Spring Security – Cache Control Headers](http://www.baeldung.com/spring-security-cache-control-headers)
+- [Basic Introduction to JMX](http://www.baeldung.com/java-management-extensions)
+- [AWS Lambda With Java](http://www.baeldung.com/java-aws-lambda)
+- [Introduction to Nashorn](http://www.baeldung.com/java-nashorn)
+- [Exceptions in Java 8 Lambda Expressions](http://www.baeldung.com/java-lambda-exceptions)
+- [Guide to the Guava BiMap](http://www.baeldung.com/guava-bimap)
+- [Iterable to Stream in Java](http://www.baeldung.com/java-iterable-to-stream)
+- [Java 8 Stream findFirst() vs. findAny()](http://www.baeldung.com/java-stream-findfirst-vs-findany)
+- [Chained Exceptions in Java](http://www.baeldung.com/java-chained-exceptions)
+- [The Java HashMap Under the Hood](http://www.baeldung.com/java-hashmap)
+- [A Guide to LinkedHashMap in Java](http://www.baeldung.com/java-linked-hashmap)
+- [A Guide to TreeMap in Java](http://www.baeldung.com/java-treemap)
@@ -2,7 +2,8 @@ package com.baeldung.algorithms;

 import java.util.Scanner;

-import com.baeldung.algorithms.annealing.SimulatedAnnealing;
+import com.baeldung.algorithms.ga.annealing.SimulatedAnnealing;
+import com.baeldung.algorithms.ga.ant_colony.AntColonyOptimization;
 import com.baeldung.algorithms.ga.binary.SimpleGeneticAlgorithm;
 import com.baeldung.algorithms.slope_one.SlopeOne;

@@ -14,6 +15,7 @@ public class RunAlgorithm {
 		System.out.println("1 - Simulated Annealing");
 		System.out.println("2 - Slope One");
 		System.out.println("3 - Simple Genetic Algorithm");
+		System.out.println("4 - Ant Colony");
 		int decision = in.nextInt();
 		switch (decision) {
 		case 1:
@@ -27,6 +29,10 @@ public class RunAlgorithm {
 			SimpleGeneticAlgorithm ga = new SimpleGeneticAlgorithm();
 			ga.runAlgorithm(50, "1011000100000100010000100000100111001000000100000100000000001111");
 			break;
+		case 4:
+			AntColonyOptimization antColony = new AntColonyOptimization(21);
+			antColony.startAntOptimization();
+			break;
 		default:
 			System.out.println("Unknown option");
 			break;
@@ -1,4 +1,4 @@
-package com.baeldung.algorithms.annealing;
+package com.baeldung.algorithms.ga.annealing;

 import lombok.Data;

@@ -1,4 +1,4 @@
-package com.baeldung.algorithms.annealing;
+package com.baeldung.algorithms.ga.annealing;

 public class SimulatedAnnealing {

@@ -1,4 +1,4 @@
-package com.baeldung.algorithms.annealing;
+package com.baeldung.algorithms.ga.annealing;

 import java.util.ArrayList;
 import java.util.Collections;
@@ -0,0 +1,37 @@
+package com.baeldung.algorithms.ga.ant_colony;
+
+public class Ant {
+
+	protected int trailSize;
+	protected int trail[];
+	protected boolean visited[];
+
+	public Ant(int tourSize) {
+		this.trailSize = tourSize;
+		this.trail = new int[tourSize];
+		this.visited = new boolean[tourSize];
+	}
+
+	protected void visitCity(int currentIndex, int city) {
+		trail[currentIndex + 1] = city;
+		visited[city] = true;
+	}
+
+	protected boolean visited(int i) {
+		return visited[i];
+	}
+
+	protected double trailLength(double graph[][]) {
+		double length = graph[trail[trailSize - 1]][trail[0]];
+		for (int i = 0; i < trailSize - 1; i++) {
+			length += graph[trail[i]][trail[i + 1]];
+		}
+		return length;
+	}
+
+	protected void clear() {
+		for (int i = 0; i < trailSize; i++)
+			visited[i] = false;
+	}
+
+}
@@ -0,0 +1,212 @@
+package com.baeldung.algorithms.ga.ant_colony;
+
+import java.util.Arrays;
+import java.util.Random;
+
+public class AntColonyOptimization {
+
+	private double c = 1.0;
+	private double alpha = 1;
+	private double beta = 5;
+	private double evaporation = 0.5;
+	private double Q = 500;
+	private double antFactor = 0.8;
+	private double randomFactor = 0.01;
+
+	private int maxIterations = 1000;
+
+	public int numberOfCities;
+	public int numberOfAnts;
+	private double graph[][];
+	private double trails[][];
+	private Ant ants[];
+	private Random random = new Random();
+	private double probabilities[];
+
+	private int currentIndex;
+
+	public int[] bestTourOrder;
+	public double bestTourLength;
+
+	public AntColonyOptimization(int noOfCities) {
+		graph = generateRandomMatrix(noOfCities);
+		numberOfCities = graph.length;
+		numberOfAnts = (int) (numberOfCities * antFactor);
+
+		trails = new double[numberOfCities][numberOfCities];
+		probabilities = new double[numberOfCities];
+		ants = new Ant[numberOfAnts];
+		for (int j = 0; j < numberOfAnts; j++) {
+			ants[j] = new Ant(numberOfCities);
+		}
+	}
+
+	/**
+	 * Generate initial solution
+	 * @param n
+	 * @return
+	 */
+	public double[][] generateRandomMatrix(int n) {
+		double[][] randomMatrix = new double[n][n];
+		random.setSeed(System.currentTimeMillis());
+		for (int i = 0; i < n; i++) {
+			for (int j = 0; j < n; j++) {
+				Integer r = random.nextInt(100) + 1;
+				randomMatrix[i][j] = Math.abs(r);
+			}
+		}
+		return randomMatrix;
+	}
+	
+	/**
+	 * Perform ant optimization
+	 * @return
+	 */
+	public int[] startAntOptimization() {
+		int[] finalResult = null;
+		for (int i = 1; i <= 3; i++) {
+			System.out.println("Attempt #" + i);
+			finalResult = solve();
+		}
+		return finalResult;
+	}
+	
+	/**
+	 * Use this method to run the main logic
+	 * @return
+	 */
+	private int[] solve() {
+		setupAnts();
+		clearTrails();
+		int iteration = 0;
+		while (iteration < maxIterations) {
+			moveAnts();
+			updateTrails();
+			updateBest();
+			iteration++;
+		}
+		System.out.println("Best tour length: " + (bestTourLength - numberOfCities));
+		System.out.println("Best tour order: " + Arrays.toString(bestTourOrder));
+		return bestTourOrder.clone();
+	}
+	
+	/**
+	 * Prepare ants for the simulation
+	 */
+	private void setupAnts() {
+		currentIndex = -1;
+		for (int i = 0; i < numberOfAnts; i++) {
+			ants[i].clear();
+			ants[i].visitCity(currentIndex, random.nextInt(numberOfCities));
+		}
+		currentIndex++;
+	}
+	
+	/**
+	 * At each iteration, move ants
+	 */
+	private void moveAnts() {
+		while (currentIndex < numberOfCities - 1) {
+			for (Ant a : ants)
+				a.visitCity(currentIndex, selectNextCity(a));
+			currentIndex++;
+		}
+	}
+	
+	/**
+	 * Select next city for each ant
+	 * @param ant
+	 * @return
+	 */
+	private int selectNextCity(Ant ant) {
+		if (random.nextDouble() < randomFactor) {
+			int t = random.nextInt(numberOfCities - currentIndex);
+			int j = -1;
+			for (int i = 0; i < numberOfCities; i++) {
+				if (!ant.visited(i)) {
+					j++;
+				}
+				if (j == t) {
+					return i;
+				}
+			}
+		}
+		calculateProbabilities(ant);
+		double r = random.nextDouble();
+		double total = 0;
+		for (int i = 0; i < numberOfCities; i++) {
+			total += probabilities[i];
+			if (total >= r) {
+				return i;
+			}
+		}
+
+		throw new RuntimeException("There are no other cities");
+	}
+
+	/**
+	 * Calculate the next city picks probabilites
+	 * @param ant
+	 */
+	private void calculateProbabilities(Ant ant) {
+		int i = ant.trail[currentIndex];
+		double pheromone = 0.0;
+		for (int l = 0; l < numberOfCities; l++) {
+			if (!ant.visited(l)) {
+				pheromone += Math.pow(trails[i][l], alpha) * Math.pow(1.0 / graph[i][l], beta);
+			}
+		}
+		for (int j = 0; j < numberOfCities; j++) {
+			if (ant.visited(j)) {
+				probabilities[j] = 0.0;
+			} else {
+				double numerator = Math.pow(trails[i][j], alpha) * Math.pow(1.0 / graph[i][j], beta);
+				probabilities[j] = numerator / pheromone;
+			}
+		}
+	}
+
+	/**
+	 * Update trails that ants used
+	 */
+	private void updateTrails() {
+		for (int i = 0; i < numberOfCities; i++) {
+			for (int j = 0; j < numberOfCities; j++) {
+				trails[i][j] *= evaporation;
+			}
+		}
+		for (Ant a : ants) {
+			double contribution = Q / a.trailLength(graph);
+			for (int i = 0; i < numberOfCities - 1; i++) {
+				trails[a.trail[i]][a.trail[i + 1]] += contribution;
+			}
+			trails[a.trail[numberOfCities - 1]][a.trail[0]] += contribution;
+		}
+	}
+
+	/**
+	 * Update the best solution
+	 */
+	private void updateBest() {
+		if (bestTourOrder == null) {
+			bestTourOrder = ants[0].trail;
+			bestTourLength = ants[0].trailLength(graph);
+		}
+		for (Ant a : ants) {
+			if (a.trailLength(graph) < bestTourLength) {
+				bestTourLength = a.trailLength(graph);
+				bestTourOrder = a.trail.clone();
+			}
+		}
+	}
+
+	/**
+	 * Clear trails after simulation
+	 */
+	private void clearTrails() {
+		for (int i = 0; i < numberOfCities; i++)
+			for (int j = 0; j < numberOfCities; j++)
+				trails[i][j] = c;
+	}
+
+}
@@ -0,0 +1,83 @@
+package com.baeldung.concurrent.locks;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Stack;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.ReentrantLock;
+
+import static java.lang.Thread.sleep;
+
+public class ReentrantLockWithCondition {
+
+	static Logger logger = LoggerFactory.getLogger(ReentrantLockWithCondition.class);
+
+	Stack<String> stack = new Stack<>();
+	int CAPACITY = 5;
+
+	ReentrantLock lock = new ReentrantLock();
+	Condition stackEmptyCondition = lock.newCondition();
+	Condition stackFullCondition = lock.newCondition();
+
+	public void pushToStack(String item) throws InterruptedException {
+		try {
+			lock.lock();
+			if (stack.size() == CAPACITY) {
+				logger.info(Thread.currentThread().getName() + " wait on stack full");
+				stackFullCondition.await();
+			}
+			logger.info("Pushing the item " + item);
+			stack.push(item);
+			stackEmptyCondition.signalAll();
+		} finally {
+			lock.unlock();
+		}
+
+	}
+
+	public String popFromStack() throws InterruptedException {
+		try {
+			lock.lock();
+			if (stack.size() == 0) {
+				logger.info(Thread.currentThread().getName() + " wait on stack empty");
+				stackEmptyCondition.await();
+			}
+			return stack.pop();
+		} finally {
+			stackFullCondition.signalAll();
+			lock.unlock();
+		}
+	}
+
+	public static void main(String[] args) {
+		final int threadCount = 2;
+		ReentrantLockWithCondition object = new ReentrantLockWithCondition();
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+		service.execute(() -> {
+			for (int i = 0; i < 10; i++) {
+				try {
+					object.pushToStack("Item " + i);
+				} catch (InterruptedException e) {
+					e.printStackTrace();
+				}
+			}
+
+		});
+
+		service.execute(() -> {
+			for (int i = 0; i < 10; i++) {
+				try {
+					logger.info("Item popped " + object.popFromStack());
+				} catch (InterruptedException e) {
+					e.printStackTrace();
+				}
+			}
+
+		});
+
+		service.shutdown();
+	}
+}
@@ -0,0 +1,92 @@
+package com.baeldung.concurrent.locks;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.ReentrantLock;
+
+import static java.lang.Thread.sleep;
+
+public class SharedObjectWithLock {
+
+	Logger logger = LoggerFactory.getLogger(SharedObjectWithLock.class);
+
+	ReentrantLock lock = new ReentrantLock(true);
+
+	int counter = 0;
+
+	public void perform() {
+
+		lock.lock();
+		logger.info("Thread - " + Thread.currentThread().getName() + " acquired the lock");
+		try {
+			logger.info("Thread - " + Thread.currentThread().getName() + " processing");
+			counter++;
+		} catch (Exception exception) {
+			logger.error(" Interrupted Exception ", exception);
+		} finally {
+			lock.unlock();
+			logger.info("Thread - " + Thread.currentThread().getName() + " released the lock");
+		}
+	}
+
+	public void performTryLock() {
+
+		logger.info("Thread - " + Thread.currentThread().getName() + " attempting to acquire the lock");
+		try {
+			boolean isLockAcquired = lock.tryLock(2, TimeUnit.SECONDS);
+			if (isLockAcquired) {
+				try {
+					logger.info("Thread - " + Thread.currentThread().getName() + " acquired the lock");
+
+					logger.info("Thread - " + Thread.currentThread().getName() + " processing");
+					sleep(1000);
+				} finally {
+					lock.unlock();
+					logger.info("Thread - " + Thread.currentThread().getName() + " released the lock");
+
+				}
+			}
+		} catch (InterruptedException exception) {
+			logger.error(" Interrupted Exception ", exception);
+		}
+		logger.info("Thread - " + Thread.currentThread().getName() + " could not acquire the lock");
+	}
+
+	public ReentrantLock getLock() {
+		return lock;
+	}
+
+	boolean isLocked() {
+		return lock.isLocked();
+	}
+
+	boolean hasQueuedThreads() {
+		return lock.hasQueuedThreads();
+	}
+
+	int getCounter() {
+		return counter;
+	}
+
+	public static void main(String[] args) {
+
+		final int threadCount = 2;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+		final SharedObjectWithLock object = new SharedObjectWithLock();
+
+		service.execute(() -> {
+			object.perform();
+		});
+		service.execute(() -> {
+			object.performTryLock();
+		});
+
+		service.shutdown();
+
+	}
+
+}
@@ -0,0 +1,104 @@
+package com.baeldung.concurrent.locks;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.locks.StampedLock;
+
+import static java.lang.Thread.sleep;
+
+public class StampedLockDemo {
+	Map<String, String> map = new HashMap<>();
+	Logger logger = LoggerFactory.getLogger(StampedLockDemo.class);
+
+	private final StampedLock lock = new StampedLock();
+
+	public void put(String key, String value) throws InterruptedException {
+		long stamp = lock.writeLock();
+
+		try {
+			logger.info(Thread.currentThread().getName() + " acquired the write lock with stamp " + stamp);
+			map.put(key, value);
+		} finally {
+			lock.unlockWrite(stamp);
+			logger.info(Thread.currentThread().getName() + " unlocked the write lock with stamp " + stamp);
+		}
+	}
+
+	public String get(String key) throws InterruptedException {
+		long stamp = lock.readLock();
+		logger.info(Thread.currentThread().getName() + " acquired the read lock with stamp " + stamp);
+		try {
+			sleep(5000);
+			return map.get(key);
+
+		} finally {
+			lock.unlockRead(stamp);
+			logger.info(Thread.currentThread().getName() + " unlocked the read lock with stamp " + stamp);
+
+		}
+
+	}
+
+	public String readWithOptimisticLock(String key) throws InterruptedException {
+		long stamp = lock.tryOptimisticRead();
+		String value = map.get(key);
+
+		if (!lock.validate(stamp)) {
+			stamp = lock.readLock();
+			try {
+				sleep(5000);
+				return map.get(key);
+
+			} finally {
+				lock.unlock(stamp);
+				logger.info(Thread.currentThread().getName() + " unlocked the read lock with stamp " + stamp);
+
+			}
+		}
+		return value;
+	}
+
+	public static void main(String[] args) {
+		final int threadCount = 4;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+		StampedLockDemo object = new StampedLockDemo();
+
+		Runnable writeTask = () -> {
+
+			try {
+				object.put("key1", "value1");
+			} catch (InterruptedException e) {
+				e.printStackTrace();
+			}
+		};
+		Runnable readTask = () -> {
+
+			try {
+				object.get("key1");
+			} catch (InterruptedException e) {
+				e.printStackTrace();
+			}
+		};
+		Runnable readOptimisticTask = () -> {
+
+			try {
+				object.readWithOptimisticLock("key1");
+			} catch (InterruptedException e) {
+				e.printStackTrace();
+			}
+		};
+		service.submit(writeTask);
+		service.submit(writeTask);
+		service.submit(readTask);
+		service.submit(readOptimisticTask);
+
+		service.shutdown();
+
+	}
+
+}
@@ -0,0 +1,120 @@
+package com.baeldung.concurrent.locks;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import static java.lang.Thread.sleep;
+
+public class SynchronizedHashMapWithRWLock {
+
+	static Map<String, String> syncHashMap = new HashMap<>();
+	Logger logger = LoggerFactory.getLogger(SynchronizedHashMapWithRWLock.class);
+
+	private final ReadWriteLock lock = new ReentrantReadWriteLock();
+	private final Lock readLock = lock.readLock();
+	private final Lock writeLock = lock.writeLock();
+
+	public void put(String key, String value) throws InterruptedException {
+
+		try {
+			writeLock.lock();
+			logger.info(Thread.currentThread().getName() + " writing");
+			syncHashMap.put(key, value);
+			sleep(1000);
+		} finally {
+			writeLock.unlock();
+		}
+
+	}
+
+	public String get(String key) {
+		try {
+			readLock.lock();
+			logger.info(Thread.currentThread().getName() + " reading");
+			return syncHashMap.get(key);
+		} finally {
+			readLock.unlock();
+		}
+	}
+
+	public String remove(String key) {
+		try {
+			writeLock.lock();
+			return syncHashMap.remove(key);
+		} finally {
+			writeLock.unlock();
+		}
+	}
+
+	public boolean containsKey(String key) {
+		try {
+			readLock.lock();
+			return syncHashMap.containsKey(key);
+		} finally {
+			readLock.unlock();
+		}
+	}
+
+	boolean isReadLockAvailable() {
+		return readLock.tryLock();
+	}
+
+	public static void main(String[] args) throws InterruptedException {
+
+		final int threadCount = 3;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+		SynchronizedHashMapWithRWLock object = new SynchronizedHashMapWithRWLock();
+
+		service.execute(new Thread(new Writer(object), "Writer"));
+		service.execute(new Thread(new Reader(object), "Reader1"));
+		service.execute(new Thread(new Reader(object), "Reader2"));
+
+		service.shutdown();
+	}
+
+	private static class Reader implements Runnable {
+
+		SynchronizedHashMapWithRWLock object;
+
+		public Reader(SynchronizedHashMapWithRWLock object) {
+			this.object = object;
+		}
+
+		@Override
+		public void run() {
+			for (int i = 0; i < 10; i++) {
+				object.get("key" + i);
+			}
+		}
+	}
+
+	private static class Writer implements Runnable {
+
+		SynchronizedHashMapWithRWLock object;
+
+		public Writer(SynchronizedHashMapWithRWLock object) {
+			this.object = object;
+		}
+
+		@Override
+		public void run() {
+			for (int i = 0; i < 10; i++) {
+				try {
+					object.put("key" + i, "value" + i);
+					sleep(1000);
+				} catch (InterruptedException e) {
+					e.printStackTrace();
+				}
+			}
+		}
+	}
+
+}
@@ -0,0 +1,18 @@
+package com.baeldung.list.listoflist;
+
+public class Pen implements Stationery {
+
+    public String name;
+
+    public Pen(String name) {
+        this.name = name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return this.name;
+    }
+}
@@ -0,0 +1,18 @@
+package com.baeldung.list.listoflist;
+
+public class Pencil implements Stationery{
+    
+    public String name;
+    
+    public Pencil(String name) {
+        this.name = name;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return this.name;
+    }
+}
--- a/Show More
+++ b/Show More