Initial commit

.gitignore

+# Project-specific
+doc/
+
+# Mac file finder metadata
+.DS_Store
+# MS Office temporary file
+~*
+# Emacs backup file
+*~
+
+# LaTeX files
+*.aux
+*.log
+*.out
+*.tex.gz
+*.synctex.gz
+*.texmk
+*.dvi
+*.fls
+*.fdb_latexmk
+
+# C files
+*.o
+*.out
+
+# Java files
+*.class
+
+# Python files
+*.pyc
+*.pyo
+
+# JetBrains (IntelliJ IDEA, PyCharm, etc) files
+.idea/
+cmake-build-*/
+out/
+bin/
+*.iml
+*.iws
+*.ipr
+
+# Eclipse files
+bin/
+.settings/
+.classpath
+.project
+
+# Maven
+target/
+
+# Miscellaneous
+tmp/
+*.tmp
+*.bak
+*.swp
+

README.md

+# Socket Chat
+
+Socket Chat is a simple 2-way chat program, essentially a bi-directional echo server/client. It is remarkably
+non-robust, as its sole purpose is to demonstrate the use of Java sockets.
\ No newline at end of file

pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         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>
+
+    <groupId>edu.unl.cse</groupId>
+    <artifactId>SocketChat</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <addClasspath>true</addClasspath>
+                            <mainClass>edu.unl.cse.socketchat.Chat</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+
+
+</project>

src/main/java/edu/unl/cse/socketchat/Chat.java

+/*
+ * Copyright (c) 2019 Christopher A. Bohn, bohn@unl.edu.
+ */
+
+package edu.unl.cse.socketchat;
+
+import java.io.*;
+import java.net.InetAddress;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.Scanner;
+
+public class Chat {
+
+    private Socket socket;
+    private Scanner scanner;
+    private boolean isHost;
+    private PrintStream[] output = new PrintStream[2];
+    private BufferedReader[] input = new BufferedReader[2];
+
+    public Chat() {
+        scanner = new Scanner(System.in);
+        try {
+            socket = connect();
+            if (isHost) {
+                input[0] = new BufferedReader(new InputStreamReader(System.in));
+                input[1] = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+                output[0] = new PrintStream(socket.getOutputStream());
+                output[1] = System.out;
+            } else {
+                input[0] = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+                input[1] = new BufferedReader(new InputStreamReader(System.in));
+                output[0] = System.out;
+                output[1] = new PrintStream(socket.getOutputStream());
+            }
+        } catch (IOException ioException) {
+            System.err.println("Connection failed: " + ioException);
+            System.exit(1);
+        }
+    }
+
+    public void communicate() {
+        System.out.println("Host goes first.");
+        String message = "";
+        int turn = 0;
+        try {
+            while (!message.equals("EXIT")) {
+                message = input[turn].readLine();
+                output[turn].println(message);
+                turn = (turn + 1) % 2;
+            }
+            socket.close();
+        } catch (IOException ioException) {
+            System.err.println("Connection dropped: " + ioException);
+            System.exit(1);
+        }
+    }
+
+    private Socket connect() throws IOException {
+        System.out.print("Are you the chat host? [Y] ");
+        String answerString = scanner.nextLine().toUpperCase();
+        char answer = answerString.length() > 0 ? answerString.charAt(0) : 'Y';
+        isHost = (answer != 'N');
+        return isHost ? connectAsServer(6858) : connectAsClient(6858);
+    }
+
+    private Socket connectAsServer(int port) throws IOException {
+        byte[] address = InetAddress.getLocalHost().getAddress();
+//        byte[] address = InetAddress.getLoopbackAddress().getAddress();
+        System.out.println("Host address: " + address[0] + "." + address[1] + "." + address[2] + "." + address[3]);
+        ServerSocket serverSocket = new ServerSocket(port);
+        return serverSocket.accept();
+    }
+
+    private Socket connectAsClient(int port) throws IOException {
+        System.out.print("Enter IP address of host <##.##.##.##>: ");
+        String addressString = scanner.nextLine();
+        String tokens[] = addressString.split("\\.");
+        byte[] address = new byte[4];
+        for (int i = 0; i < 4; i++) {
+            address[i] = Byte.valueOf(tokens[i]);
+        }
+        return new Socket(InetAddress.getByAddress(address), port);
+    }
+
+    public static void main(String args[]) {
+        Chat chat = new Chat();
+        chat.communicate();
+    }
+}