BAEL-1018 - Introduction to MBassador (#2551)

libraries/pom.xml

@@ -519,6 +519,11 @@
             <artifactId>yarg</artifactId>
             <version>2.0.4</version>
         </dependency>
+        <dependency>
+            <groupId>net.engio</groupId>
+            <artifactId>mbassador</artifactId>
+            <version>1.3.1</version>
+        </dependency>
     </dependencies>
     <repositories>
         <repository>

libraries/src/main/java/com/baeldung/mbassador/AckMessage.java

@@ -0,0 +1,5 @@
+package com.baeldung.mbassador;
+
+public class AckMessage extends Message {
+
+}

libraries/src/main/java/com/baeldung/mbassador/Message.java

@@ -0,0 +1,5 @@
+package com.baeldung.mbassador;
+
+public class Message {
+
+}

libraries/src/main/java/com/baeldung/mbassador/RejectMessage.java

@@ -0,0 +1,15 @@
+package com.baeldung.mbassador;
+
+public class RejectMessage extends Message {
+
+    int code;
+
+    public int getCode() {
+        return code;
+    }
+
+    public void setCode(int code) {
+        this.code = code;
+    }
+
+}

libraries/src/test/java/com/baeldung/mbassador/MBassadorAsyncDispatchTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.mbassador;
+
+import net.engio.mbassy.bus.MBassador;
+import net.engio.mbassy.listener.Handler;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.awaitility.Awaitility.await;
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertNotNull;
+
+public class MBassadorAsyncDispatchTest {
+
+    private MBassador dispatcher = new MBassador();
+    private String testString;
+    private AtomicBoolean ready = new AtomicBoolean(false);
+
+    @Before
+    public void prepareTests() {
+        dispatcher.subscribe(this);
+    }
+
+    @Test
+    public void whenAsyncDispatched_thenMessageReceived() {
+        dispatcher.post("foobar").asynchronously();
+        await().untilAtomic(ready, equalTo(true));
+        assertNotNull(testString);
+    }
+
+    @Handler
+    public void handleStringMessage(String message) {
+        this.testString = message;
+        ready.set(true);
+    }
+}

libraries/src/test/java/com/baeldung/mbassador/MBassadorAsyncInvocationTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.mbassador;
+
+import net.engio.mbassy.bus.MBassador;
+import net.engio.mbassy.listener.Handler;
+import net.engio.mbassy.listener.Invoke;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.awaitility.Awaitility.await;
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertFalse;
+
+public class MBassadorAsyncInvocationTest {
+
+    private MBassador dispatcher = new MBassador();
+
+    private Integer testInteger;
+    private String invocationThreadName;
+    private AtomicBoolean ready = new AtomicBoolean(false);
+
+    @Before
+    public void prepareTests() {
+        dispatcher.subscribe(this);
+    }
+
+    @Test
+    public void whenHandlerAsync_thenHandled() {
+
+        dispatcher.post(42).now();
+
+        await().untilAtomic(ready, equalTo(true));
+        assertNotNull(testInteger);
+        assertFalse(Thread.currentThread().getName().equals(invocationThreadName));
+    }
+
+    @Handler(delivery = Invoke.Asynchronously)
+    public void handleIntegerMessage(Integer message) {
+        this.invocationThreadName = Thread.currentThread().getName();
+        this.testInteger = message;
+        ready.set(true);
+    }
+}

libraries/src/test/java/com/baeldung/mbassador/MBassadorBasicTest.java

@@ -0,0 +1,69 @@
+package com.baeldung.mbassador;
+
+import net.engio.mbassy.bus.MBassador;
+import net.engio.mbassy.bus.common.DeadMessage;
+import net.engio.mbassy.listener.Handler;
+import org.junit.Before;
+import org.junit.Test;
+
+import static junit.framework.TestCase.assertTrue;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+public class MBassadorBasicTest {
+
+    private MBassador dispatcher = new MBassador();
+
+    private String messageString;
+    private Integer messageInteger;
+    private Object deadEvent;
+
+    @Before
+    public void prepareTests() {
+        dispatcher.subscribe(this);
+    }
+
+    @Test
+    public void whenStringDispatched_thenHandleString() {
+        dispatcher.post("TestString").now();
+        assertNotNull(messageString);
+        assertEquals("TestString", messageString);
+    }
+
+    @Test
+    public void whenIntegerDispatched_thenHandleInteger() {
+        dispatcher.post(42).now();
+        assertNull(messageString);
+        assertNotNull(messageInteger);
+        assertTrue(42 == messageInteger);
+    }
+
+    @Test
+    public void whenLongDispatched_thenDeadEvent() {
+        dispatcher.post(42L).now();
+        assertNull(messageString);
+        assertNull(messageInteger);
+        assertNotNull(deadEvent);
+        assertTrue(deadEvent instanceof Long);
+        assertTrue(42L == (Long) deadEvent);
+    }
+
+    @Handler
+    public void handleString(String message) {
+        messageString = message;
+    }
+
+    @Handler
+    public void handleInteger(Integer message) {
+        messageInteger = message;
+    }
+
+    @Handler
+    public void handleDeadEvent(DeadMessage message) {
+
+        deadEvent = message.getMessage();
+
+    }
+
+}

libraries/src/test/java/com/baeldung/mbassador/MBassadorConfigurationTest.java

@@ -0,0 +1,90 @@
+package com.baeldung.mbassador;
+
+import net.engio.mbassy.bus.MBassador;
+import net.engio.mbassy.bus.error.IPublicationErrorHandler;
+import net.engio.mbassy.bus.error.PublicationError;
+import net.engio.mbassy.listener.Handler;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.*;
+
+import static junit.framework.TestCase.assertTrue;
+import static org.junit.Assert.*;
+
+public class MBassadorConfigurationTest implements IPublicationErrorHandler {
+
+    private MBassador dispatcher;
+    private String messageString;
+    private Throwable errorCause;
+
+    private LinkedList<Integer> list = new LinkedList<>();
+
+    @Before
+    public void prepareTests() {
+        dispatcher = new MBassador(this);
+        dispatcher.subscribe(this);
+    }
+
+    @Test
+    public void whenErrorOccurs_thenErrorHandler() {
+        dispatcher.post("Error").now();
+        assertNull(messageString);
+        assertNotNull(errorCause);
+    }
+
+    @Test
+    public void whenNoErrorOccurs_thenStringHandler() {
+        dispatcher.post("Errol").now();
+        assertNull(errorCause);
+        assertNotNull(messageString);
+    }
+
+    @Test
+    public void whenRejectDispatched_thenPriorityHandled() {
+        dispatcher.post(new RejectMessage()).now();
+
+        // Items should pop() off in reverse priority order
+        assertTrue(1 == list.pop());
+        assertTrue(3 == list.pop());
+        assertTrue(5 == list.pop());
+    }
+
+    @Handler
+    public void handleString(String message) {
+
+        if ("Error".equals(message)) {
+            throw new Error("BOOM");
+        }
+
+        messageString = message;
+
+    }
+
+    @Override
+    public void handleError(PublicationError error) {
+        errorCause = error.getCause().getCause();
+    }
+
+    @Handler(priority = 5)
+    public void handleRejectMessage5(RejectMessage rejectMessage) {
+        list.push(5);
+    }
+
+    @Handler(priority = 3)
+    public void handleRejectMessage3(RejectMessage rejectMessage) {
+        list.push(3);
+    }
+
+    @Handler(priority = 2, rejectSubtypes = true)
+    public void handleMessage(Message rejectMessage) {
+        list.push(3);
+    }
+
+    @Handler(priority = 0)
+    public void handleRejectMessage0(RejectMessage rejectMessage) {
+        list.push(1);
+    }
+}

libraries/src/test/java/com/baeldung/mbassador/MBassadorFilterTest.java

@@ -0,0 +1,103 @@
+package com.baeldung.mbassador;
+
+import net.engio.mbassy.bus.MBassador;
+import net.engio.mbassy.bus.common.DeadMessage;
+import net.engio.mbassy.bus.common.FilteredMessage;
+import net.engio.mbassy.listener.Filter;
+import net.engio.mbassy.listener.Filters;
+import net.engio.mbassy.listener.Handler;
+import org.junit.Before;
+import org.junit.Test;
+
+import static junit.framework.TestCase.assertTrue;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+public class MBassadorFilterTest {
+
+    private MBassador dispatcher = new MBassador();
+
+    private Message baseMessage;
+    private Message subMessage;
+    private String testString;
+    private FilteredMessage filteredMessage;
+    private RejectMessage rejectMessage;
+    private DeadMessage deadMessage;
+
+    @Before
+    public void prepareTests() {
+        dispatcher.subscribe(this);
+    }
+
+    @Test
+    public void whenMessageDispatched_thenMessageFiltered() {
+        dispatcher.post(new Message()).now();
+        assertNotNull(baseMessage);
+        assertNull(subMessage);
+    }
+
+    @Test
+    public void whenRejectDispatched_thenRejectFiltered() {
+        dispatcher.post(new RejectMessage()).now();
+        assertNotNull(subMessage);
+        assertNull(baseMessage);
+    }
+
+    @Test
+    public void whenShortStringDispatched_thenStringHandled() {
+        dispatcher.post("foobar").now();
+        assertNotNull(testString);
+    }
+
+    @Test
+    public void whenLongStringDispatched_thenStringFiltered() {
+        dispatcher.post("foobar!").now();
+        assertNull(testString);
+        // filtered only populated when messages does not pass any filters
+        assertNotNull(filteredMessage);
+        assertTrue(filteredMessage.getMessage() instanceof String);
+        assertNull(deadMessage);
+    }
+
+    @Test
+    public void whenWrongRejectDispatched_thenRejectFiltered() {
+        RejectMessage testReject = new RejectMessage();
+        testReject.setCode(-1);
+        dispatcher.post(testReject).now();
+        assertNull(rejectMessage);
+        assertNotNull(subMessage);
+        assertEquals(-1, ((RejectMessage) subMessage).getCode());
+    }
+
+    @Handler(filters = { @Filter(Filters.RejectSubtypes.class) })
+    public void handleBaseMessage(Message message) {
+        this.baseMessage = message;
+    }
+
+    @Handler(filters = { @Filter(Filters.SubtypesOnly.class) })
+    public void handleSubMessage(Message message) {
+        this.subMessage = message;
+    }
+
+    @Handler(condition = "msg.length() < 7")
+    public void handleStringMessage(String message) {
+        this.testString = message;
+    }
+
+    @Handler(condition = "msg.getCode() != -1")
+    public void handleRejectMessage(RejectMessage rejectMessage) {
+        this.rejectMessage = rejectMessage;
+    }
+
+    @Handler
+    public void handleFilterMessage(FilteredMessage message) {
+        this.filteredMessage = message;
+    }
+
+    @Handler
+    public void handleDeadMessage(DeadMessage deadMessage) {
+        this.deadMessage = deadMessage;
+    }
+
+}

libraries/src/test/java/com/baeldung/mbassador/MBassadorHierarchyTest.java

@@ -0,0 +1,61 @@
+package com.baeldung.mbassador;
+
+import net.engio.mbassy.bus.MBassador;
+import net.engio.mbassy.listener.Handler;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class MBassadorHierarchyTest {
+
+    private MBassador dispatcher = new MBassador();
+
+    private Message message;
+    private AckMessage ackMessage;
+    private RejectMessage rejectMessage;
+
+    @Before
+    public void prepareTests() {
+        dispatcher.subscribe(this);
+    }
+
+    @Test
+    public void whenMessageDispatched_thenMessageHandled() {
+        dispatcher.post(new Message()).now();
+        assertNotNull(message);
+        assertNull(ackMessage);
+        assertNull(rejectMessage);
+    }
+
+    @Test
+    public void whenRejectDispatched_thenMessageAndRejectHandled() {
+        dispatcher.post(new RejectMessage()).now();
+        assertNotNull(message);
+        assertNotNull(rejectMessage);
+        assertNull(ackMessage);
+    }
+
+    @Test
+    public void whenAckDispatched_thenMessageAndAckHandled() {
+        dispatcher.post(new AckMessage()).now();
+        assertNotNull(message);
+        assertNotNull(ackMessage);
+        assertNull(rejectMessage);
+    }
+
+    @Handler
+    public void handleMessage(Message message) {
+        this.message = message;
+    }
+
+    @Handler
+    public void handleRejectMessage(RejectMessage message) {
+        rejectMessage = message;
+    }
+
+    @Handler
+    public void handleAckMessage(AckMessage message) {
+        ackMessage = message;
+    }
+}