Merge branch 'master' of https://github.com/eugenp/tutorials into BAEL-1525-Check-if-a-String-is-a-palindrome

algorithms/src/main/java/com/baeldung/algorithms/maze/solver/BFSMazeSolver.java

@@ -0,0 +1,52 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+public class BFSMazeSolver {
+    private static final int[][] DIRECTIONS = { { 0, 1 }, { 1, 0 }, { 0, -1 }, { -1, 0 } };
+
+    public List<Coordinate> solve(Maze maze) {
+        LinkedList<Coordinate> nextToVisit = new LinkedList<>();
+        Coordinate start = maze.getEntry();
+        nextToVisit.add(start);
+
+        while (!nextToVisit.isEmpty()) {
+            Coordinate cur = nextToVisit.remove();
+
+            if (!maze.isValidLocation(cur.getX(), cur.getY()) || maze.isExplored(cur.getX(), cur.getY())) {
+                continue;
+            }
+
+            if (maze.isWall(cur.getX(), cur.getY())) {
+                maze.setVisited(cur.getX(), cur.getY(), true);
+                continue;
+            }
+
+            if (maze.isExit(cur.getX(), cur.getY())) {
+                return backtrackPath(cur);
+            }
+
+            for (int[] direction : DIRECTIONS) {
+                Coordinate coordinate = new Coordinate(cur.getX() + direction[0], cur.getY() + direction[1], cur);
+                nextToVisit.add(coordinate);
+                maze.setVisited(cur.getX(), cur.getY(), true);
+            }
+        }
+        return Collections.emptyList();
+    }
+
+    private List<Coordinate> backtrackPath(Coordinate cur) {
+        List<Coordinate> path = new ArrayList<>();
+        Coordinate iter = cur;
+
+        while (iter != null) {
+            path.add(iter);
+            iter = iter.parent;
+        }
+
+        return path;
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/maze/solver/Coordinate.java

@@ -0,0 +1,31 @@
+package com.baeldung.algorithms.maze.solver;
+
+public class Coordinate {
+    int x;
+    int y;
+    Coordinate parent;
+
+    public Coordinate(int x, int y) {
+        this.x = x;
+        this.y = y;
+        this.parent = null;
+    }
+
+    public Coordinate(int x, int y, Coordinate parent) {
+        this.x = x;
+        this.y = y;
+        this.parent = parent;
+    }
+
+    int getX() {
+        return x;
+    }
+
+    int getY() {
+        return y;
+    }
+
+    Coordinate getParent() {
+        return parent;
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/maze/solver/DFSMazeSolver.java

@@ -0,0 +1,48 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class DFSMazeSolver {
+    private static final int[][] DIRECTIONS = { { 0, 1 }, { 1, 0 }, { 0, -1 }, { -1, 0 } };
+
+    public List<Coordinate> solve(Maze maze) {
+        List<Coordinate> path = new ArrayList<>();
+        if (explore(maze, maze.getEntry()
+            .getX(),
+            maze.getEntry()
+                .getY(),
+            path)) {
+            return path;
+        }
+        return Collections.emptyList();
+    }
+
+    private boolean explore(Maze maze, int row, int col, List<Coordinate> path) {
+        if (!maze.isValidLocation(row, col) || maze.isWall(row, col) || maze.isExplored(row, col)) {
+            return false;
+        }
+
+        path.add(new Coordinate(row, col));
+        maze.setVisited(row, col, true);
+
+        if (maze.isExit(row, col)) {
+            return true;
+        }
+
+        for (int[] direction : DIRECTIONS) {
+            Coordinate coordinate = getNextCoordinate(row, col, direction[0], direction[1]);
+            if (explore(maze, coordinate.getX(), coordinate.getY(), path)) {
+                return true;
+            }
+        }
+
+        path.remove(path.size() - 1);
+        return false;
+    }
+
+    private Coordinate getNextCoordinate(int row, int col, int i, int j) {
+        return new Coordinate(row + i, col + j);
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/maze/solver/Maze.java

@@ -0,0 +1,141 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Scanner;
+
+public class Maze {
+    private static final int ROAD = 0;
+    private static final int WALL = 1;
+    private static final int START = 2;
+    private static final int EXIT = 3;
+    private static final int PATH = 4;
+
+    private int[][] maze;
+    private boolean[][] visited;
+    private Coordinate start;
+    private Coordinate end;
+
+    public Maze(File maze) throws FileNotFoundException {
+        String fileText = "";
+        try (Scanner input = new Scanner(maze)) {
+            while (input.hasNextLine()) {
+                fileText += input.nextLine() + "\n";
+            }
+        }
+        initializeMaze(fileText);
+    }
+
+    private void initializeMaze(String text) {
+        if (text == null || (text = text.trim()).length() == 0) {
+            throw new IllegalArgumentException("empty lines data");
+        }
+
+        String[] lines = text.split("[\r]?\n");
+        maze = new int[lines.length][lines[0].length()];
+        visited = new boolean[lines.length][lines[0].length()];
+
+        for (int row = 0; row < getHeight(); row++) {
+            if (lines[row].length() != getWidth()) {
+                throw new IllegalArgumentException("line " + (row + 1) + " wrong length (was " + lines[row].length() + " but should be " + getWidth() + ")");
+            }
+
+            for (int col = 0; col < getWidth(); col++) {
+                if (lines[row].charAt(col) == '#')
+                    maze[row][col] = WALL;
+                else if (lines[row].charAt(col) == 'S') {
+                    maze[row][col] = START;
+                    start = new Coordinate(row, col);
+                } else if (lines[row].charAt(col) == 'E') {
+                    maze[row][col] = EXIT;
+                    end = new Coordinate(row, col);
+                } else
+                    maze[row][col] = ROAD;
+            }
+        }
+    }
+
+    public int getHeight() {
+        return maze.length;
+    }
+
+    public int getWidth() {
+        return maze[0].length;
+    }
+
+    public Coordinate getEntry() {
+        return start;
+    }
+
+    public Coordinate getExit() {
+        return end;
+    }
+
+    public boolean isExit(int x, int y) {
+        return x == end.getX() && y == end.getY();
+    }
+
+    public boolean isStart(int x, int y) {
+        return x == start.getX() && y == start.getY();
+    }
+
+    public boolean isExplored(int row, int col) {
+        return visited[row][col];
+    }
+
+    public boolean isWall(int row, int col) {
+        return maze[row][col] == WALL;
+    }
+
+    public void setVisited(int row, int col, boolean value) {
+        visited[row][col] = value;
+    }
+
+    public boolean isValidLocation(int row, int col) {
+        if (row < 0 || row >= getHeight() || col < 0 || col >= getWidth()) {
+            return false;
+        }
+        return true;
+    }
+
+    public void printPath(List<Coordinate> path) {
+        int[][] tempMaze = Arrays.stream(maze)
+            .map(int[]::clone)
+            .toArray(int[][]::new);
+        for (Coordinate coordinate : path) {
+            if (isStart(coordinate.getX(), coordinate.getY()) || isExit(coordinate.getX(), coordinate.getY())) {
+                continue;
+            }
+            tempMaze[coordinate.getX()][coordinate.getY()] = PATH;
+        }
+        System.out.println(toString(tempMaze));
+    }
+
+    public String toString(int[][] maze) {
+        StringBuilder result = new StringBuilder(getWidth() * (getHeight() + 1));
+        for (int row = 0; row < getHeight(); row++) {
+            for (int col = 0; col < getWidth(); col++) {
+                if (maze[row][col] == ROAD) {
+                    result.append(' ');
+                } else if (maze[row][col] == WALL) {
+                    result.append('#');
+                } else if (maze[row][col] == START) {
+                    result.append('S');
+                } else if (maze[row][col] == EXIT) {
+                    result.append('E');
+                } else {
+                    result.append('.');
+                }
+            }
+            result.append('\n');
+        }
+        return result.toString();
+    }
+
+    public void reset() {
+        for (int i = 0; i < visited.length; i++)
+            Arrays.fill(visited[i], false);
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/maze/solver/MazeDriver.java

@@ -0,0 +1,34 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.io.File;
+import java.util.List;
+
+public class MazeDriver {
+    public static void main(String[] args) throws Exception {
+        File maze1 = new File("src/main/resources/maze/maze1.txt");
+        File maze2 = new File("src/main/resources/maze/maze2.txt");
+
+        execute(maze1);
+        execute(maze2);
+    }
+
+    private static void execute(File file) throws Exception {
+        Maze maze = new Maze(file);
+        dfs(maze);
+        bfs(maze);
+    }
+
+    private static void bfs(Maze maze) {
+        BFSMazeSolver bfs = new BFSMazeSolver();
+        List<Coordinate> path = bfs.solve(maze);
+        maze.printPath(path);
+        maze.reset();
+    }
+
+    private static void dfs(Maze maze) {
+        DFSMazeSolver dfs = new DFSMazeSolver();
+        List<Coordinate> path = dfs.solve(maze);
+        maze.printPath(path);
+        maze.reset();
+    }
+}

algorithms/src/main/resources/maze/maze1.txt

@@ -0,0 +1,12 @@
+S ########
+#        #
+# ### ## #
+# #    # #
+# #  # # #
+# ## #####
+# #      #
+# # #  # #
+##### ####
+#   #    E
+# #    # #
+##########

algorithms/src/main/resources/maze/maze2.txt

@@ -0,0 +1,22 @@
+S ##########################
+# #      #                 #
+# # ####   ############### #
+# # #    # #               #
+# # #### # # ###############
+# # #    # # #             #
+# # # #### ### ########### #
+# # # #        #           #
+#       ################## #
+#########    # # #       # #
+# #       #### # ####### # #
+# # ### ###  # # #       # #
+#   #       ##   # ##### # #
+##### #######  # #     # # #
+#     #       ## ## #### # #
+# ##### #######     #      #
+#       #       ############
+####### #########        # #
+#       #         ######## #
+# ####### ###### ##   #    E
+#         #         #   ## #
+############################

spring-integration/pom.xml

@@ -18,7 +18,7 @@
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <spring.integration.version>4.3.5.RELEASE</spring.integration.version>
+        <spring.version>5.0.1.RELEASE</spring.version>
         <spring-social.version>1.1.4.RELEASE</spring-social.version>
         <javax-mail.version>1.4.7</javax-mail.version>
         <javax-activation.version>1.1.1</javax-activation.version>
@@ -68,7 +68,7 @@
         <dependency>
             <groupId>org.springframework.integration</groupId>
             <artifactId>spring-integration-core</artifactId>
-            <version>${spring.integration.version}</version>
+            <version>${spring.version}</version>
         </dependency>
         <dependency>
             <groupId>javax.activation</groupId>
@@ -84,17 +84,17 @@
         <dependency>
             <groupId>org.springframework.integration</groupId>
             <artifactId>spring-integration-twitter</artifactId>
-            <version>${spring.integration.version}</version>
+            <version>${spring.version}</version>
         </dependency>
         <dependency>
             <groupId>org.springframework.integration</groupId>
             <artifactId>spring-integration-mail</artifactId>
-            <version>${spring.integration.version}</version>
+            <version>${spring.version}</version>
         </dependency>
         <dependency>
             <groupId>org.springframework.integration</groupId>
             <artifactId>spring-integration-ftp</artifactId>
-            <version>${spring.integration.version}</version>
+            <version>${spring.version}</version>
         </dependency>
         <dependency>
             <groupId>org.springframework.social</groupId>
@@ -104,7 +104,36 @@
         <dependency>
             <groupId>org.springframework.integration</groupId>
             <artifactId>spring-integration-file</artifactId>
-            <version>${spring.integration.version}</version>
+            <version>${spring.version}</version>
+        </dependency>
+        
+		<dependency>
+		    <groupId>org.springframework.security</groupId>
+		    <artifactId>spring-security-core</artifactId>
+		    <version>${spring.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.security</groupId>
+			<artifactId>spring-security-config</artifactId>
+			<version>${spring.version}</version>
+		</dependency>
+		<dependency>
+		    <groupId>org.springframework.integration</groupId>
+		    <artifactId>spring-integration-security</artifactId>
+		    <version>${spring.version}</version>
+		</dependency>
+		
+		<dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-test</artifactId>
+            <version>${spring.version}</version>
+            <scope>test</scope>
+        </dependency>
+		<dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-test</artifactId>
+            <version>${spring.version}</version>
+            <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>junit</groupId>

spring-integration/src/main/java/com/baeldung/si/security/MessageConsumer.java

@@ -0,0 +1,45 @@
+package com.baeldung.si.security;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.logging.Logger;
+
+import org.springframework.integration.annotation.ServiceActivator;
+import org.springframework.messaging.Message;
+import org.springframework.stereotype.Service;
+
+@Service
+public class MessageConsumer {
+
+    private String messageContent;
+
+    private Map<String, String> messagePSContent = new ConcurrentHashMap<>();
+
+    public String getMessageContent() {
+        return messageContent;
+    }
+
+    public void setMessageContent(String messageContent) {
+        this.messageContent = messageContent;
+    }
+
+    public Map<String, String> getMessagePSContent() {
+        return messagePSContent;
+    }
+
+    public void setMessagePSContent(Map<String, String> messagePSContent) {
+        this.messagePSContent = messagePSContent;
+    }
+
+    @ServiceActivator(inputChannel = "endDirectChannel")
+    public void endDirectFlow(Message<?> message) {
+        setMessageContent(message.getPayload().toString());
+    }
+
+    @ServiceActivator(inputChannel = "finalPSResult")
+    public void endPSFlow(Message<?> message) {
+        Logger.getAnonymousLogger().info(Thread.currentThread().getName() + " has completed ---------------------------");
+        messagePSContent.put(Thread.currentThread().getName(), (String) message.getPayload());
+    }
+
+}

spring-integration/src/main/java/com/baeldung/si/security/SecuredDirectChannel.java

@@ -0,0 +1,50 @@
+package com.baeldung.si.security;
+
+import java.util.logging.Logger;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.integration.annotation.ServiceActivator;
+import org.springframework.integration.channel.DirectChannel;
+import org.springframework.integration.config.EnableIntegration;
+import org.springframework.integration.security.channel.ChannelSecurityInterceptor;
+import org.springframework.integration.security.channel.SecuredChannel;
+import org.springframework.messaging.Message;
+import org.springframework.security.access.AccessDecisionManager;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.security.authentication.AuthenticationManager;
+
+@Configuration
+@EnableIntegration
+public class SecuredDirectChannel {
+
+    @Bean(name = "startDirectChannel")
+    @SecuredChannel(interceptor = "channelSecurityInterceptor", sendAccess = { "ROLE_VIEWER", "jane" })
+    public DirectChannel startDirectChannel() {
+        return new DirectChannel();
+    }
+
+    @ServiceActivator(inputChannel = "startDirectChannel", outputChannel = "endDirectChannel")
+    @PreAuthorize("hasRole('ROLE_LOGGER')")
+    public Message<?> logMessage(Message<?> message) {
+        Logger.getAnonymousLogger().info(message.toString());
+        return message;
+    }
+
+    @Bean(name = "endDirectChannel")
+    @SecuredChannel(interceptor = "channelSecurityInterceptor", sendAccess = { "ROLE_EDITOR" })
+    public DirectChannel endDirectChannel() {
+        return new DirectChannel();
+    }
+
+    @Autowired
+    @Bean
+    public ChannelSecurityInterceptor channelSecurityInterceptor(AuthenticationManager authenticationManager, AccessDecisionManager customAccessDecisionManager) {
+        ChannelSecurityInterceptor channelSecurityInterceptor = new ChannelSecurityInterceptor();
+        channelSecurityInterceptor.setAuthenticationManager(authenticationManager);
+        channelSecurityInterceptor.setAccessDecisionManager(customAccessDecisionManager);
+        return channelSecurityInterceptor;
+    }
+
+}

spring-integration/src/main/java/com/baeldung/si/security/SecurityConfig.java

@@ -0,0 +1,46 @@
+package com.baeldung.si.security;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.integration.security.channel.ChannelSecurityInterceptor;
+import org.springframework.security.access.AccessDecisionManager;
+import org.springframework.security.access.AccessDecisionVoter;
+import org.springframework.security.access.vote.AffirmativeBased;
+import org.springframework.security.access.vote.RoleVoter;
+import org.springframework.security.authentication.AuthenticationManager;
+import org.springframework.security.config.annotation.method.configuration.EnableGlobalMethodSecurity;
+import org.springframework.security.config.annotation.method.configuration.GlobalMethodSecurityConfiguration;
+
+@Configuration
+@EnableGlobalMethodSecurity(prePostEnabled = true)
+public class SecurityConfig extends GlobalMethodSecurityConfiguration {
+
+    @Override
+    @Bean
+    public AuthenticationManager authenticationManager() throws Exception {
+        return super.authenticationManager();
+    }
+
+    @Bean
+    public AccessDecisionManager customAccessDecisionManager() {
+        List<AccessDecisionVoter<? extends Object>> decisionVoters = new ArrayList<>();
+        decisionVoters.add(new RoleVoter());
+        decisionVoters.add(new UsernameAccessDecisionVoter());
+        AccessDecisionManager accessDecisionManager = new AffirmativeBased(decisionVoters);
+        return accessDecisionManager;
+    }
+
+    @Autowired
+    @Bean
+    public ChannelSecurityInterceptor channelSecurityInterceptor(AuthenticationManager authenticationManager, AccessDecisionManager customAccessDecisionManager) {
+        ChannelSecurityInterceptor channelSecurityInterceptor = new ChannelSecurityInterceptor();
+        channelSecurityInterceptor.setAuthenticationManager(authenticationManager);
+        channelSecurityInterceptor.setAccessDecisionManager(customAccessDecisionManager);
+        return channelSecurityInterceptor;
+    }
+
+}

spring-integration/src/main/java/com/baeldung/si/security/SecurityPubSubChannel.java

@@ -0,0 +1,82 @@
+package com.baeldung.si.security;
+
+import java.util.stream.Collectors;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.integration.annotation.ServiceActivator;
+import org.springframework.integration.channel.DirectChannel;
+import org.springframework.integration.channel.PublishSubscribeChannel;
+import org.springframework.integration.config.EnableIntegration;
+import org.springframework.integration.config.GlobalChannelInterceptor;
+import org.springframework.integration.security.channel.SecuredChannel;
+import org.springframework.integration.security.channel.SecurityContextPropagationChannelInterceptor;
+import org.springframework.integration.support.DefaultMessageBuilderFactory;
+import org.springframework.integration.support.MessageBuilder;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.support.ChannelInterceptor;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.security.core.context.SecurityContext;
+import org.springframework.security.core.context.SecurityContextHolder;
+
+@Configuration
+@EnableIntegration
+public class SecurityPubSubChannel {
+
+    @Bean(name = "startPSChannel")
+    @SecuredChannel(interceptor = "channelSecurityInterceptor", sendAccess = "ROLE_VIEWER")
+    public PublishSubscribeChannel startChannel() {
+        return new PublishSubscribeChannel(executor());
+    }
+
+    @ServiceActivator(inputChannel = "startPSChannel", outputChannel = "finalPSResult")
+    @PreAuthorize("hasRole('ROLE_LOGGER')")
+    public Message<?> changeMessageToRole(Message<?> message) {
+        return buildNewMessage(getRoles(), message);
+    }
+
+    @ServiceActivator(inputChannel = "startPSChannel", outputChannel = "finalPSResult")
+    @PreAuthorize("hasRole('ROLE_VIEWER')")
+    public Message<?> changeMessageToUserName(Message<?> message) {
+        return buildNewMessage(getUsername(), message);
+    }
+
+    @Bean(name = "finalPSResult")
+    public DirectChannel finalPSResult() {
+        return new DirectChannel();
+    }
+
+    @Bean
+    @GlobalChannelInterceptor(patterns = { "startPSChannel", "endDirectChannel" })
+    public ChannelInterceptor securityContextPropagationInterceptor() {
+        return new SecurityContextPropagationChannelInterceptor();
+    }
+
+    @Bean
+    public ThreadPoolTaskExecutor executor() {
+        ThreadPoolTaskExecutor pool = new ThreadPoolTaskExecutor();
+        pool.setCorePoolSize(10);
+        pool.setMaxPoolSize(10);
+        pool.setWaitForTasksToCompleteOnShutdown(true);
+        return pool;
+    }
+
+    public String getRoles() {
+        SecurityContext securityContext = SecurityContextHolder.getContext();
+        return securityContext.getAuthentication().getAuthorities().stream().map(auth -> auth.getAuthority()).collect(Collectors.joining(","));
+    }
+
+    public String getUsername() {
+        SecurityContext securityContext = SecurityContextHolder.getContext();
+        return securityContext.getAuthentication().getName();
+    }
+
+    public Message<String> buildNewMessage(String content, Message<?> message) {
+        DefaultMessageBuilderFactory builderFactory = new DefaultMessageBuilderFactory();
+        MessageBuilder<String> messageBuilder = builderFactory.withPayload(content);
+        messageBuilder.copyHeaders(message.getHeaders());
+        return messageBuilder.build();
+    }
+
+}

spring-integration/src/main/java/com/baeldung/si/security/UsernameAccessDecisionVoter.java

@@ -0,0 +1,45 @@
+package com.baeldung.si.security;
+
+import java.util.Collection;
+
+import org.springframework.security.access.AccessDecisionVoter;
+import org.springframework.security.access.ConfigAttribute;
+import org.springframework.security.core.Authentication;
+
+public class UsernameAccessDecisionVoter implements AccessDecisionVoter<Object> {
+    private String rolePrefix = "ROLE_";
+
+    @Override
+    public boolean supports(ConfigAttribute attribute) {
+        if ((attribute.getAttribute() != null)
+                && !attribute.getAttribute().startsWith(rolePrefix)) {
+            return true;
+        }else {
+            return false;
+        }
+    }
+
+    @Override
+    public boolean supports(Class<?> clazz) {
+        return true;
+    }
+
+    @Override
+    public int vote(Authentication authentication, Object object, Collection<ConfigAttribute> attributes) {
+        if (authentication == null) {
+            return ACCESS_DENIED;
+        }
+        String name = authentication.getName();
+        int result = ACCESS_ABSTAIN;
+        for (ConfigAttribute attribute : attributes) {
+            if (this.supports(attribute)) {
+                result = ACCESS_DENIED;
+                if (attribute.getAttribute().equals(name)) {
+                    return ACCESS_GRANTED;
+                }
+            }
+        }
+        return result;
+    }
+
+}

spring-integration/src/test/java/com/baeldung/si/TestSpringIntegrationSecurity.java

@@ -0,0 +1,81 @@
+package com.baeldung.si;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.messaging.SubscribableChannel;
+import org.springframework.messaging.support.GenericMessage;
+import org.springframework.security.access.AccessDeniedException;
+import org.springframework.security.authentication.AuthenticationCredentialsNotFoundException;
+import org.springframework.security.test.context.support.WithMockUser;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import com.baeldung.si.security.MessageConsumer;
+import com.baeldung.si.security.SecuredDirectChannel;
+import com.baeldung.si.security.SecurityConfig;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = { SecurityConfig.class, SecuredDirectChannel.class, MessageConsumer.class })
+public class TestSpringIntegrationSecurity {
+
+    @Autowired
+    SubscribableChannel startDirectChannel;
+
+    @Autowired
+    MessageConsumer messageConsumer;
+
+    final String DIRECT_CHANNEL_MESSAGE = "Direct channel message";
+
+    @Test(expected = AuthenticationCredentialsNotFoundException.class)
+    public void givenNoUser_whenSendToDirectChannel_thenCredentialNotFound() {
+        startDirectChannel.send(new GenericMessage<String>(DIRECT_CHANNEL_MESSAGE));
+    }
+
+    @Test(expected = AccessDeniedException.class)
+    @WithMockUser(username = "jane", roles = { "LOGGER" })
+    public void givenRoleLogger_whenSendMessageToDirectChannel_thenAccessDenied() throws Throwable {
+        try {
+            startDirectChannel.send(new GenericMessage<String>(DIRECT_CHANNEL_MESSAGE));
+        } catch (Exception e) {
+            throw e.getCause();
+        }
+    }
+
+    @Test(expected = AccessDeniedException.class)
+    @WithMockUser(username = "jane")
+    public void givenJane_whenSendMessageToDirectChannel_thenAccessDenied() throws Throwable {
+        try {
+            startDirectChannel.send(new GenericMessage<String>(DIRECT_CHANNEL_MESSAGE));
+        } catch (Exception e) {
+            throw e.getCause();
+        }
+    }
+
+    @Test(expected = AccessDeniedException.class)
+    @WithMockUser(roles = { "VIEWER" })
+    public void givenRoleViewer_whenSendToDirectChannel_thenAccessDenied() throws Throwable {
+        try {
+            startDirectChannel.send(new GenericMessage<String>(DIRECT_CHANNEL_MESSAGE));
+        } catch (Exception e) {
+            throw e.getCause();
+        }
+    }
+
+    @Test
+    @WithMockUser(roles = { "LOGGER", "VIEWER", "EDITOR" })
+    public void givenRoleLoggerAndUser_whenSendMessageToDirectChannel_thenFlowCompletedSuccessfully() {
+        startDirectChannel.send(new GenericMessage<String>(DIRECT_CHANNEL_MESSAGE));
+        assertEquals(DIRECT_CHANNEL_MESSAGE, messageConsumer.getMessageContent());
+    }
+
+    @Test
+    @WithMockUser(username = "jane", roles = { "LOGGER", "EDITOR" })
+    public void givenJaneLoggerEditor_whenSendToDirectChannel_thenFlowCompleted() {
+        startDirectChannel.send(new GenericMessage<String>(DIRECT_CHANNEL_MESSAGE));
+        assertEquals(DIRECT_CHANNEL_MESSAGE, messageConsumer.getMessageContent());
+    }
+
+}

spring-integration/src/test/java/com/baeldung/si/TestSpringIntegrationSecurityExecutor.java

@@ -0,0 +1,68 @@
+package com.baeldung.si;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.messaging.SubscribableChannel;
+import org.springframework.messaging.support.GenericMessage;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+import org.springframework.security.test.context.support.WithMockUser;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import com.baeldung.si.security.MessageConsumer;
+import com.baeldung.si.security.SecurityConfig;
+import com.baeldung.si.security.SecurityPubSubChannel;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = { SecurityPubSubChannel.class, MessageConsumer.class, SecurityConfig.class })
+public class TestSpringIntegrationSecurityExecutor {
+
+    @Autowired
+    SubscribableChannel startPSChannel;
+
+    @Autowired
+    MessageConsumer messageConsumer;
+
+    @Autowired
+    ThreadPoolTaskExecutor executor;
+
+    final String DIRECT_CHANNEL_MESSAGE = "Direct channel message";
+
+    @Before
+    public void clearData() {
+        messageConsumer.setMessagePSContent(new ConcurrentHashMap<>());
+        executor.setWaitForTasksToCompleteOnShutdown(true);
+    }
+
+    @Test
+    @WithMockUser(username = "user", roles = { "VIEWER" })
+    public void givenRoleUser_whenSendMessageToPSChannel_thenNoMessageArrived() throws IllegalStateException, InterruptedException {
+        startPSChannel.send(new GenericMessage<String>(DIRECT_CHANNEL_MESSAGE));
+
+        executor.getThreadPoolExecutor().awaitTermination(2, TimeUnit.SECONDS);
+
+        assertEquals(1, messageConsumer.getMessagePSContent().size());
+        assertTrue(messageConsumer.getMessagePSContent().values().contains("user"));
+    }
+
+    @Test
+    @WithMockUser(username = "user", roles = { "LOGGER", "VIEWER" })
+    public void givenRoleUserAndLogger_whenSendMessageToPSChannel_then2GetMessages() throws IllegalStateException, InterruptedException {
+        startPSChannel.send(new GenericMessage<String>(DIRECT_CHANNEL_MESSAGE));
+
+        executor.getThreadPoolExecutor().awaitTermination(2, TimeUnit.SECONDS);
+
+        assertEquals(2, messageConsumer.getMessagePSContent().size());
+        assertTrue(messageConsumer.getMessagePSContent().values().contains("user"));
+        assertTrue(messageConsumer.getMessagePSContent().values().contains("ROLE_LOGGER,ROLE_VIEWER"));
+    }
+
+}

testing-modules/testing/pom.xml

@@ -173,7 +173,7 @@
         <jacoco.version>0.7.7.201606060606</jacoco.version>
         <guava.version>21.0</guava.version>
         <assertj-guava.version>3.1.0</assertj-guava.version>
-        <assertj-core.version>3.6.1</assertj-core.version>
+        <assertj-core.version>3.9.0</assertj-core.version>
         <assertj-generator.version>2.1.0</assertj-generator.version>
         <truth.version>0.32</truth.version>
         <jUnitParams.version>1.1.0</jUnitParams.version>

testing-modules/testing/src/test/java/com/baeldung/testing/assertj/exceptions/Java7StyleAssertions.java

@@ -0,0 +1,24 @@
+package com.baeldung.testing.assertj.exceptions;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.failBecauseExceptionWasNotThrown;
+
+import org.junit.Test;
+
+public class Java7StyleAssertions {
+
+    @Test
+    public void whenDividingByZero_thenArithmeticException() {
+        try {
+            int numerator = 10;
+            int denominator = 0;
+            int quotient = numerator / denominator;
+            fail("ArithmeticException expected because dividing by zero yields an ArithmeticException.");
+            failBecauseExceptionWasNotThrown(ArithmeticException.class);
+        } catch (Exception e) {
+            assertThat(e).hasMessage("/ by zero");
+            assertThat(e).isInstanceOf(ArithmeticException.class);
+        }
+    }
+}

testing-modules/testing/src/test/java/com/baeldung/testing/assertj/exceptions/Java8StyleAssertions.java

@@ -0,0 +1,42 @@
+package com.baeldung.testing.assertj.exceptions;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.catchThrowable;
+
+import org.junit.Test;
+
+public class Java8StyleAssertions {
+
+    @Test
+    public void whenDividingByZero_thenArithmeticException() {
+        assertThatThrownBy(() -> {
+            int numerator = 10;
+            int denominator = 0;
+            int quotient = numerator / denominator;
+        }).isInstanceOf(ArithmeticException.class)
+            .hasMessageContaining("/ by zero");
+
+        assertThatExceptionOfType(ArithmeticException.class).isThrownBy(() -> {
+            int numerator = 10;
+            int denominator = 0;
+            int quotient = numerator / denominator;
+        })
+            .withMessageContaining("/ by zero");
+
+        // BDD style:
+
+        // when
+        Throwable thrown = catchThrowable(() -> {
+            int numerator = 10;
+            int denominator = 0;
+            int quotient = numerator / denominator;
+        });
+
+        // then
+        assertThat(thrown).isInstanceOf(ArithmeticException.class)
+            .hasMessageContaining("/ by zero");
+
+    }
+}