clustering/server/src/main/java/org/wildfly/clustering/server/dispatcher/ChannelCommandDispatcherFactory.java

@@ -264,7 +264,7 @@ public void viewAccepted(View view) {
                 this.members.keySet().removeAll(leftMembers);
             }
 
-            if (this.listeners.isEmpty()) {
+            if (!this.listeners.isEmpty()) {
                 Address localAddress = this.dispatcher.getChannel().getAddress();
                 ViewMembership oldMembership = new ViewMembership(localAddress, oldView, this);
                 ViewMembership membership = new ViewMembership(localAddress, view, this);

testsuite/integration/clustering/src/test/java/org/jboss/as/test/clustering/cluster/group/GroupListenerTestCase.java

@@ -0,0 +1,136 @@
+/*
+ * JBoss, Home of Professional Open Source.
+ * Copyright 2019, Red Hat, Inc., and individual contributors
+ * as indicated by the @author tags. See the copyright.txt file in the
+ * distribution for a full listing of individual contributors.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+
+package org.jboss.as.test.clustering.cluster.group;
+
+import static org.junit.Assert.*;
+
+import org.jboss.arquillian.container.test.api.Deployment;
+import org.jboss.arquillian.container.test.api.TargetsContainer;
+import org.jboss.arquillian.junit.Arquillian;
+import org.jboss.as.test.clustering.cluster.AbstractClusteringTestCase;
+import org.jboss.as.test.clustering.cluster.group.bean.ClusterTopology;
+import org.jboss.as.test.clustering.cluster.group.bean.ClusterTopologyRetriever;
+import org.jboss.as.test.clustering.cluster.group.bean.ClusterTopologyRetrieverBean;
+import org.jboss.as.test.clustering.ejb.EJBDirectory;
+import org.jboss.as.test.clustering.ejb.RemoteEJBDirectory;
+import org.jboss.as.test.shared.TimeoutUtil;
+import org.jboss.shrinkwrap.api.Archive;
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * Integration test for the listener facility of a {@link Group}.
+ * @author Paul Ferraro
+ */
+@RunWith(Arquillian.class)
+public class GroupListenerTestCase extends AbstractClusteringTestCase {
+    private static final String MODULE_NAME = GroupListenerTestCase.class.getSimpleName();
+    private static final long VIEW_CHANGE_WAIT = TimeoutUtil.adjust(2000);
+
+    @Deployment(name = DEPLOYMENT_1, managed = false, testable = false)
+    @TargetsContainer(NODE_1)
+    public static Archive<?> deployment1() {
+        return createDeployment();
+    }
+
+    @Deployment(name = DEPLOYMENT_2, managed = false, testable = false)
+    @TargetsContainer(NODE_2)
+    public static Archive<?> deployment2() {
+        return createDeployment();
+    }
+
+    private static Archive<?> createDeployment() {
+        final JavaArchive ejbJar = ShrinkWrap.create(JavaArchive.class, MODULE_NAME + ".jar");
+        ejbJar.addPackage(ClusterTopologyRetriever.class.getPackage());
+        return ejbJar;
+    }
+
+    @Test
+    public void test() throws Exception {
+        try (EJBDirectory directory = new RemoteEJBDirectory(MODULE_NAME)) {
+            ClusterTopologyRetriever bean = directory.lookupStateless(ClusterTopologyRetrieverBean.class, ClusterTopologyRetriever.class);
+
+            ClusterTopology topology = bean.getClusterTopology();
+            assertEquals(topology.getCurrentMembers().toString(), 2, topology.getCurrentMembers().size());
+            assertTrue(topology.getCurrentMembers().toString(), topology.getCurrentMembers().contains(NODE_1));
+            assertTrue(topology.getCurrentMembers().toString(), topology.getCurrentMembers().contains(NODE_2));
+            assertEquals(topology.getPreviousMembers().toString(), 0, topology.getPreviousMembers().size());
+
+            stop(NODE_2);
+
+            Thread.sleep(VIEW_CHANGE_WAIT);
+
+            topology = bean.getClusterTopology();
+            assertEquals(topology.getCurrentMembers().toString(), 1, topology.getCurrentMembers().size());
+            assertTrue(topology.getCurrentMembers().toString(), topology.getCurrentMembers().contains(NODE_1));
+            assertEquals(topology.getPreviousMembers().toString(), 2, topology.getPreviousMembers().size());
+            assertTrue(topology.getPreviousMembers().toString(), topology.getPreviousMembers().contains(NODE_1));
+            assertTrue(topology.getPreviousMembers().toString(), topology.getPreviousMembers().contains(NODE_2));
+
+            start(NODE_2);
+
+            Thread.sleep(VIEW_CHANGE_WAIT);
+
+            topology = bean.getClusterTopology();
+            assertEquals(topology.getCurrentMembers().toString(), 2, topology.getCurrentMembers().size());
+            assertTrue(topology.getCurrentMembers().toString(), topology.getCurrentMembers().contains(NODE_1));
+            assertTrue(topology.getCurrentMembers().toString(), topology.getCurrentMembers().contains(NODE_2));
+            if (topology.getTargetMember().equals(NODE_1)) {
+                assertEquals(topology.getPreviousMembers().toString(), 1, topology.getPreviousMembers().size());
+                assertTrue(topology.getPreviousMembers().toString(), topology.getPreviousMembers().contains(NODE_1));
+            } else {
+                // Since node 2 was just started, its previous membership will be empty
+                assertEquals(topology.getPreviousMembers().toString(), 0, topology.getPreviousMembers().size());
+            }
+
+            stop(NODE_1);
+
+            Thread.sleep(VIEW_CHANGE_WAIT);
+
+            topology = bean.getClusterTopology();
+            assertEquals(topology.getCurrentMembers().toString(), 1, topology.getCurrentMembers().size());
+            assertTrue(topology.getCurrentMembers().toString(), topology.getCurrentMembers().contains(NODE_2));
+            assertEquals(topology.getPreviousMembers().toString(), 2, topology.getPreviousMembers().size());
+            assertTrue(topology.getPreviousMembers().toString(), topology.getPreviousMembers().contains(NODE_1));
+            assertTrue(topology.getPreviousMembers().toString(), topology.getPreviousMembers().contains(NODE_2));
+
+            start(NODE_1);
+
+            Thread.sleep(VIEW_CHANGE_WAIT);
+
+            topology = bean.getClusterTopology();
+            assertEquals(topology.getCurrentMembers().toString(), 2, topology.getCurrentMembers().size());
+            assertTrue(topology.getCurrentMembers().toString(), topology.getCurrentMembers().contains(NODE_1));
+            assertTrue(topology.getCurrentMembers().toString(), topology.getCurrentMembers().contains(NODE_2));
+            if (topology.getTargetMember().equals(NODE_2)) {
+                assertEquals(topology.getPreviousMembers().toString(), 1, topology.getPreviousMembers().size());
+                assertTrue(topology.getPreviousMembers().toString(), topology.getPreviousMembers().contains(NODE_2));
+            } else {
+                // Since node 1 was just started, its previous membership will be empty
+                assertEquals(topology.getPreviousMembers().toString(), 0, topology.getPreviousMembers().size());
+            }
+        }
+    }
+}

testsuite/integration/clustering/src/test/java/org/jboss/as/test/clustering/cluster/group/bean/ClusterTopology.java

@@ -0,0 +1,30 @@
+package org.jboss.as.test.clustering.cluster.group.bean;
+
+import java.io.Serializable;
+import java.util.List;
+
+public class ClusterTopology implements Serializable {
+    private static final long serialVersionUID = 413628123168918069L;
+
+    private final String targetMember;
+    private final List<String> currentMembers;
+    private final List<String> previousMembers;
+
+    public ClusterTopology(String targetMember, List<String> currentMembers, List<String> previousMembers) {
+        this.targetMember = targetMember;
+        this.currentMembers = currentMembers;
+        this.previousMembers = previousMembers;
+    }
+
+    public String getTargetMember() {
+        return this.targetMember;
+    }
+
+    public List<String> getCurrentMembers() {
+        return this.currentMembers;
+    }
+
+    public List<String> getPreviousMembers() {
+        return this.previousMembers;
+    }
+}

testsuite/integration/clustering/src/test/java/org/jboss/as/test/clustering/cluster/group/bean/ClusterTopologyRetriever.java

@@ -0,0 +1,6 @@
+package org.jboss.as.test.clustering.cluster.group.bean;
+
+public interface ClusterTopologyRetriever {
+
+    ClusterTopology getClusterTopology();
+}

testsuite/integration/clustering/src/test/java/org/jboss/as/test/clustering/cluster/group/bean/ClusterTopologyRetrieverBean.java

@@ -0,0 +1,28 @@
+package org.jboss.as.test.clustering.cluster.group.bean;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import javax.ejb.EJB;
+import javax.ejb.Remote;
+import javax.ejb.Stateless;
+
+import org.wildfly.clustering.group.Membership;
+import org.wildfly.clustering.group.Node;
+
+@Stateless
+@Remote(ClusterTopologyRetriever.class)
+public class ClusterTopologyRetrieverBean implements ClusterTopologyRetriever {
+    @EJB
+    private Group group;
+
+    @Override
+    public ClusterTopology getClusterTopology() {
+        return new ClusterTopology(this.group.getLocalMember().getName(), getNames(this.group.getMembership()), getNames(this.group.getPreviousMembership()));
+    }
+
+    private static List<String> getNames(Membership membership) {
+        return (membership != null) ? membership.getMembers().stream().map(Node::getName).collect(Collectors.toList()) : Collections.emptyList();
+    }
+}

testsuite/integration/clustering/src/test/java/org/jboss/as/test/clustering/cluster/group/bean/Group.java

@@ -0,0 +1,32 @@
+/*
+ * JBoss, Home of Professional Open Source.
+ * Copyright 2019, Red Hat, Inc., and individual contributors
+ * as indicated by the @author tags. See the copyright.txt file in the
+ * distribution for a full listing of individual contributors.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+
+package org.jboss.as.test.clustering.cluster.group.bean;
+
+import org.wildfly.clustering.group.Membership;
+
+/**
+ * @author Paul Ferraro
+ */
+public interface Group extends org.wildfly.clustering.group.Group {
+    Membership getPreviousMembership();
+}

testsuite/integration/clustering/src/test/java/org/jboss/as/test/clustering/cluster/group/bean/GroupBean.java

@@ -0,0 +1,75 @@
+package org.jboss.as.test.clustering.cluster.group.bean;
+
+import javax.annotation.PostConstruct;
+import javax.annotation.PreDestroy;
+import javax.annotation.Resource;
+import javax.ejb.Local;
+import javax.ejb.Singleton;
+import javax.ejb.Startup;
+
+import org.wildfly.clustering.Registration;
+import org.wildfly.clustering.group.GroupListener;
+import org.wildfly.clustering.group.Membership;
+import org.wildfly.clustering.group.Node;
+
+@Singleton
+@Startup
+@Local(Group.class)
+public class GroupBean implements Group, GroupListener {
+
+    @Resource(lookup = "java:jboss/clustering/group/default")
+    private org.wildfly.clustering.group.Group group;
+    private Registration registration;
+    private volatile Membership previousMembership;
+
+    @PostConstruct
+    public void init() {
+        this.registration = this.group.register(this);
+    }
+
+    @PreDestroy
+    public void destroy() {
+        this.registration.close();
+    }
+
+    @Override
+    public void membershipChanged(Membership previousMembership, Membership membership, boolean merged) {
+        this.previousMembership = previousMembership;
+    }
+
+    @Deprecated
+    @Override
+    public void removeListener(org.wildfly.clustering.group.Group.Listener listener) {
+        this.group.removeListener(listener);
+    }
+
+    @Override
+    public String getName() {
+        return this.group.getName();
+    }
+
+    @Override
+    public Node getLocalMember() {
+        return this.group.getLocalMember();
+    }
+
+    @Override
+    public Membership getMembership() {
+        return this.group.getMembership();
+    }
+
+    @Override
+    public boolean isSingleton() {
+        return this.group.isSingleton();
+    }
+
+    @Override
+    public Registration register(GroupListener object) {
+        return this.group.register(object);
+    }
+
+    @Override
+    public Membership getPreviousMembership() {
+        return this.previousMembership;
+    }
+}