SmackReactor/NIO, Java8/Android19, Pretty print XML, FSM connections

This commit adds
- SmackReactor / NIO
- a framework for finite state machine connections
- support for Java 8
- pretty printed XML debug output

It also
- reworks the integration test framework
- raises the minimum Android API level to 19
- introduces XmppNioTcpConnection

Furthermore fixes SMACK-801 (at least partly). Java 8 language
features are available, but not all runtime library methods. For that
we would need to raise the Android API level to 24 or higher.

smack-repl/build.gradle

@@ -37,3 +37,8 @@ task printClasspath(dependsOn: assemble) {
         println sourceSets.main.runtimeClasspath.asPath
     }
 }
+
+task printXmppNioTcpConnectionStateGraph(type: JavaExec) {
+	classpath sourceSets.main.runtimeClasspath
+	main 'org.igniterealtime.smack.smackrepl.StateGraph'
+}

smack-repl/src/main/java/org/igniterealtime/smack/smackrepl/Nio.java

@@ -0,0 +1,109 @@
+/**
+ *
+ * Copyright 2018 Florian Schmaus
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.igniterealtime.smack.smackrepl;
+
+import java.io.IOException;
+import java.util.Date;
+import java.util.logging.Logger;
+
+import org.jivesoftware.smack.ConnectionConfiguration.SecurityMode;
+import org.jivesoftware.smack.SmackException;
+import org.jivesoftware.smack.XMPPException;
+import org.jivesoftware.smack.compression.XMPPInputOutputStream;
+import org.jivesoftware.smack.compression.XMPPInputOutputStream.FlushMethod;
+import org.jivesoftware.smack.debugger.ConsoleDebugger;
+import org.jivesoftware.smack.debugger.SmackDebuggerFactory;
+import org.jivesoftware.smack.packet.Message;
+import org.jivesoftware.smack.tcp.XMPPTCPConnectionConfiguration;
+import org.jivesoftware.smack.tcp.XmppNioTcpConnection;
+
+import org.jxmpp.util.XmppDateTime;
+
+public class Nio {
+
+    private static final Logger LOGGER = Logger.getLogger(Nio.class.getName());
+
+    public static void main(String[] args) throws SmackException, IOException, XMPPException, InterruptedException {
+        doNio(args[0], args[1], args[2]);
+    }
+
+    public static void doNio(String username, String password, String service)
+            throws SmackException, IOException, XMPPException, InterruptedException {
+        boolean useTls = true;
+        boolean useCompression = true;
+        boolean useFullFlush = true;
+        boolean javaNetDebug = false;
+        boolean smackDebug = false;
+
+        if (useFullFlush) {
+            XMPPInputOutputStream.setFlushMethod(FlushMethod.FULL_FLUSH);
+        }
+
+        if (javaNetDebug) {
+            System.setProperty("javax.net.debug", "all");
+        }
+
+        final SecurityMode securityMode;
+        if (useTls) {
+            securityMode = SecurityMode.required;
+        } else {
+            securityMode = SecurityMode.disabled;
+        }
+
+        final SmackDebuggerFactory smackDebuggerFactory;
+        if (smackDebug) {
+            smackDebuggerFactory = ConsoleDebugger.Factory.INSTANCE;
+        } else {
+            smackDebuggerFactory = null;
+        }
+
+        XMPPTCPConnectionConfiguration configuration = XMPPTCPConnectionConfiguration.builder()
+                .setUsernameAndPassword(username, password)
+                .setXmppDomain(service)
+                .setDebuggerFactory(smackDebuggerFactory)
+                .setCompressionEnabled(useCompression)
+                .setSecurityMode(securityMode)
+                .build();
+
+        XmppNioTcpConnection connection = new XmppNioTcpConnection(configuration);
+
+        connection.setReplyTimeout(5 * 60 * 1000);
+
+        connection.addConnectionStateMachineListener((event, c) -> {
+            LOGGER.info("Connection event: " + event);
+        });
+
+        connection.connect();
+
+        connection.login();
+
+        Message message = new Message("flo@geekplace.eu",
+                "It is alive! " + XmppDateTime.formatXEP0082Date(new Date()));
+        connection.sendStanza(message);
+
+        Thread.sleep(1000);
+
+        connection.disconnect();
+
+        XmppNioTcpConnection.Stats connectionStats = connection.getStats();
+
+        // CHECKSTYLE:OFF
+        System.out.println("NIO successfully finished, yeah!\n" + connectionStats);
+        // CHECKSTYLE:ON
+    }
+
+}

smack-repl/src/main/java/org/igniterealtime/smack/smackrepl/StateGraph.java

@@ -0,0 +1,44 @@
+/**
+ *
+ * Copyright 2018 Florian Schmaus
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.igniterealtime.smack.smackrepl;
+
+import java.io.PrintWriter;
+import java.lang.reflect.InvocationTargetException;
+import java.util.Collections;
+
+import org.jivesoftware.smack.fsm.StateDescriptor;
+import org.jivesoftware.smack.fsm.StateDescriptorGraph;
+import org.jivesoftware.smack.fsm.StateDescriptorGraph.GraphVertex;
+import org.jivesoftware.smack.tcp.XmppNioTcpConnection;
+
+public class StateGraph {
+
+    @SuppressWarnings("DefaultCharset")
+    public static void main(String[] args) throws InstantiationException, IllegalAccessException,
+            IllegalArgumentException, InvocationTargetException, NoSuchMethodException, SecurityException {
+        GraphVertex<StateDescriptor> stateGraph = StateDescriptorGraph.constructStateDescriptorGraph(XmppNioTcpConnection.getBackwardEdgesStateDescriptors());
+
+        PrintWriter pw = new PrintWriter(System.out);
+
+        boolean breakStateName = args.length == 0;
+
+        StateDescriptorGraph.stateDescriptorGraphToDot(Collections.singleton(stateGraph), pw, breakStateName);
+
+        pw.flush();
+    }
+
+}