split into two modules, document the differences

.gitignore

@@ -1,3 +1,5 @@
 target/
 .idea/
-*.iml
+*.iml
+.mvn/
+logs/

Readme.md

@@ -2,26 +2,30 @@
 
 Teflon is a simple, configurable peer to peer chat application implemented in Java. It uses IPV6 multicast over UDP to transmit, Swing for a user interface, and JSON serialization.
 
-### Building ###
+### Modules ###
 
-    mvn compile
+There are two Maven modules, one implementing the core network event loop, and the other providing a simple Swing wrapper around the former, which is packaged as a runnable Jar.
 
 ### Generating Binaries ###
 
     mvn install
 
+_note: the resulting runnable Jar will appear at the following path: swing\target\swing-{version}-....jar_
+
 ### Configuring ###
 
-You need a configuration in the working directory of the program, of name "teflon.json".
+You need a configuration file in the working directory of the program, of name "teflon.json".
 
 Here is the documentation on each of the fields:
 
 * udpPort - the port to send and receive on
-* inputBufferLength - the largest message buffer you want to receive
+* bufferLength - the largest message buffer you want to receive
 * backlogLength - how many messages to store in memory before dropping
-* multicastGroup - the IPv6 multicast group address to join
+* hostAddress - a host address, probably the IPv6 multicast group address to join
 * interfaceName - the network interface name to join a multicast group with
 
+_note: see the provided teflon.json reference in the swing module._
+
 #### Network Interfaces ####
 
 If you run the program with a command line argument -L, it will list the names of all available interfaces.

core/.gitignore

@@ -0,0 +1,27 @@
+/target/
+!.mvn/wrapper/maven-wrapper.jar
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+/build/
+
+.mvn

core/pom.xml

@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
+         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>
+    <parent>
+        <groupId>name.maxdeliso</groupId>
+        <artifactId>teflon</artifactId>
+        <version>1.0.5-SNAPSHOT</version>
+    </parent>
+    <groupId>name.maxdeliso.teflon</groupId>
+    <artifactId>core</artifactId>
+    <version>1.0.5-SNAPSHOT</version>
+    <name>core</name>
+    <description>core Teflon classes</description>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>2.8.5</version>
+            <scope>compile</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.google.dagger</groupId>
+            <artifactId>dagger</artifactId>
+            <version>${dagger.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>1.7.25</version>
+        </dependency>
+    </dependencies>
+</project>

core/src/main/java/module-info.java

@@ -0,0 +1,10 @@
+module name.maxdeliso.teflon.core {
+    requires slf4j.api;
+    requires gson;
+    requires dagger;
+    requires javax.inject;
+
+    exports name.maxdeliso.teflon.core.data;
+    exports name.maxdeliso.teflon.core.net;
+    exports name.maxdeliso.teflon.core.di;
+}

src/main/java/name/maxdeliso/teflon/data/JsonMessageMarshaller.java → core/src/main/java/name/maxdeliso/teflon/core/data/JsonMessageMarshaller.java

@@ -1,4 +1,4 @@
-package name.maxdeliso.teflon.data;
+package name.maxdeliso.teflon.core.data;
 
 import com.google.gson.Gson;
 import com.google.gson.JsonSyntaxException;

src/main/java/name/maxdeliso/teflon/data/Message.java → core/src/main/java/name/maxdeliso/teflon/core/data/Message.java

@@ -1,4 +1,4 @@
-package name.maxdeliso.teflon.data;
+package name.maxdeliso.teflon.core.data;
 
 /**
  * A simple message class with a sender id and a string body.

src/main/java/name/maxdeliso/teflon/data/MessageMarshaller.java → core/src/main/java/name/maxdeliso/teflon/core/data/MessageMarshaller.java

@@ -1,9 +1,10 @@
-package name.maxdeliso.teflon.data;
+package name.maxdeliso.teflon.core.data;
 
 import java.nio.ByteBuffer;
 import java.util.Optional;
 
 public interface MessageMarshaller {
     Optional<Message> bufferToMessage(final byte[] buffer);
+
     ByteBuffer messageToBuffer(final Message message);
 }

core/src/main/java/name/maxdeliso/teflon/core/di/TeflonCoreModule.java

@@ -0,0 +1,89 @@
+package name.maxdeliso.teflon.core.di;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import dagger.Module;
+import dagger.Provides;
+import name.maxdeliso.teflon.core.data.JsonMessageMarshaller;
+import name.maxdeliso.teflon.core.data.Message;
+import name.maxdeliso.teflon.core.net.NetSelector;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.inject.Named;
+import javax.inject.Singleton;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketAddress;
+import java.net.SocketException;
+import java.net.UnknownHostException;
+import java.nio.ByteBuffer;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.function.BiConsumer;
+import java.util.function.Supplier;
+
+@Module
+public class TeflonCoreModule {
+    private static final Logger LOG = LoggerFactory.getLogger(TeflonCoreModule.class);
+
+    @Provides
+    @Singleton
+    BlockingQueue<Message> provideMessageQueue(@Named("teflon.backlogLength") final int backlogLength) {
+        return new LinkedBlockingQueue<>(backlogLength);
+    }
+
+    @Provides
+    @Singleton
+    InetAddress provideInetAddress(@Named("teflon.host.address") final String hostAddress) {
+        try {
+            // NOTE: this causes a DNS Query to run
+            return InetAddress.getByName(hostAddress);
+        } catch (UnknownHostException uhe) {
+            LOG.error("failed to process multicast group from config", uhe);
+            throw new RuntimeException(uhe);
+        }
+    }
+
+    @Provides
+    @Singleton
+    NetworkInterface provideNetworkInterface(@Named("teflon.host.interface") final String hostInterface) {
+        try {
+            // NOTE: this invokes some platform specific code
+            return NetworkInterface.getByName(hostInterface);
+        } catch (final SocketException se) {
+            LOG.error("failed to process interface name from config", se);
+            throw new RuntimeException(se);
+        }
+    }
+
+    @Provides
+    @Singleton
+    NetSelector provideNetSelector(@Named("teflon.udp.port") final int udpPort,
+                                   @Named("teflon.udp.bufferLength") final int bufferLength,
+                                   final BiConsumer<SocketAddress, byte[]> incomingConsumer,
+                                   final InetAddress multicastGroupAddress,
+                                   final NetworkInterface multicastInterface,
+                                   final Supplier<ByteBuffer> outgoingDataSupplier) {
+        return new NetSelector(
+                udpPort,
+                bufferLength,
+                incomingConsumer,
+                multicastGroupAddress,
+                multicastInterface,
+                outgoingDataSupplier);
+
+    }
+
+    @Provides
+    @Singleton
+    Gson provideGSON() {
+        return new GsonBuilder().create();
+    }
+
+    @Provides
+    @Singleton
+    JsonMessageMarshaller provideJsonMessageMarshaller(final Gson gson) {
+        return new JsonMessageMarshaller(gson);
+    }
+}

src/main/java/name/maxdeliso/teflon/net/NetSelector.java → core/src/main/java/name/maxdeliso/teflon/core/net/NetSelector.java

@@ -1,6 +1,5 @@
-package name.maxdeliso.teflon.net;
+package name.maxdeliso.teflon.core.net;
 
-import name.maxdeliso.teflon.config.Config;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -26,7 +25,6 @@
 public class NetSelector {
     private static final Logger LOG = LoggerFactory.getLogger(NetSelector.class);
 
-    private final AtomicBoolean alive;
     private final ByteBuffer incomingBuffer;
     private final InetSocketAddress multicastSendSocketAddress;
     private final InetSocketAddress multicastListenSocketAddress;
@@ -35,19 +33,20 @@ public class NetSelector {
     private final NetworkInterface multicastInterface;
     private final Supplier<ByteBuffer> outgoingMessageSupplier;
 
-    public NetSelector(final AtomicBoolean alive,
+    private final AtomicBoolean alive = new AtomicBoolean(true);
+
+    public NetSelector(final int udpPort,
+                       final int bufferLength,
                        final BiConsumer<SocketAddress, byte[]> incomingByteBufferConsumer,
                        final InetAddress multicastGroupAddress,
                        final NetworkInterface multicastInterface,
-                       final Supplier<ByteBuffer> outgoingDataSupplier,
-                       final Config config) {
-        this.alive = alive;
+                       final Supplier<ByteBuffer> outgoingDataSupplier) {
         this.incomingByteBufferConsumer = incomingByteBufferConsumer;
         this.multicastGroupAddress = multicastGroupAddress;
         this.multicastInterface = multicastInterface;
-        this.incomingBuffer = ByteBuffer.allocate(config.getInputBufferLength());
-        this.multicastSendSocketAddress = new InetSocketAddress(multicastGroupAddress, config.getUdpPort());
-        this.multicastListenSocketAddress = new InetSocketAddress(config.getUdpPort());
+        this.incomingBuffer = ByteBuffer.allocate(bufferLength);
+        this.multicastSendSocketAddress = new InetSocketAddress(multicastGroupAddress, udpPort);
+        this.multicastListenSocketAddress = new InetSocketAddress(udpPort);
         this.outgoingMessageSupplier = outgoingDataSupplier;
     }
 
@@ -82,8 +81,7 @@ public void selectLoop() {
                                 .map(bufferToSend -> {
                                     try {
                                         final var bufferLength = bufferToSend.array().length;
-                                        final var sentBytes = datagramChannel
-                                                .send(bufferToSend, multicastSendSocketAddress);
+                                        final var sentBytes = datagramChannel.send(bufferToSend, multicastSendSocketAddress);
                                         LOG.debug("sent {} of {} bytes over the wire", sentBytes, bufferLength);
                                         return bufferLength == sentBytes;
                                     } catch (IOException exc) {
@@ -117,4 +115,8 @@ private DatagramChannel setupDatagramChannel() throws IOException {
         channel.join(multicastGroupAddress, multicastInterface);
         return channel;
     }
+
+    public void signalExit() {
+        this.alive.set(false);
+    }
 }