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start implementing a command line user interface
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‎src/net/sharksystem/cmdline/CmdLineUI.java‎

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package net.sharksystem.cmdline;
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import net.sharksystem.util.localloop.TCPChannel;
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import sun.rmi.transport.tcp.TCPConnection;
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import java.io.*;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.StringTokenizer;
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/**
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* commands
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* - open
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* - connect
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* - list
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* - kill
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*
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* @author thsc
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*/
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public class CmdLineUI {
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public static final String CONNECT = "connect";
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public static final String OPEN = "open";
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public static final String EXIT = "exit";
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public static final String LIST = "list";
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public static final String KILL = "kill";
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private final PrintStream consoleOutput;
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private final BufferedReader userInput;
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public static void main(String[] args) {
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PrintStream os = System.out;
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os.println("Welcome SN2 version 0.1");
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CmdLineUI userCmd = new CmdLineUI(os, System.in);
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userCmd.printUsage();
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userCmd.runGame();
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}
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public CmdLineUI(PrintStream os, InputStream is) {
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this.consoleOutput = os;
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this.userInput = new BufferedReader(new InputStreamReader(is));
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}
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public void printUsage() {
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StringBuilder b = new StringBuilder();
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b.append("\n");
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b.append("\n");
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b.append("valid commands:");
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b.append("\n");
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b.append(CONNECT);
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b.append(".. connect to remote engine");
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b.append("\n");
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b.append(OPEN);
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b.append(".. open socket");
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b.append("\n");
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b.append(EXIT);
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b.append(".. exit");
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this.consoleOutput.println(b.toString());
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}
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public void printUsage(String cmdString, String comment) {
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PrintStream out = this.consoleOutput;
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if(comment == null) comment = " ";
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out.println("malformed command: " + comment);
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out.println("use:");
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switch(cmdString) {
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case CONNECT:
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out.println(CONNECT + " IP/DNS-Name_remoteHost remotePort");
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out.println("example: " + CONNECT + " localhost 7070");
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out.println("tries to connect to localhost:7070");
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break;
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case OPEN:
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out.println(OPEN + " localPort");
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out.println("example: " + OPEN + " 7070");
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out.println("opens a server socket #7070");
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break;
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case LIST:
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out.println("lists all open connections / client and server");
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break;
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case KILL:
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out.println(KILL + " channel name");
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out.println("example: " + KILL + "localhost:7070");
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out.println("kills channel named localhost:7070");
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out.println("channel names are produced by using list");
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break;
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}
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out.println("unknown command: " + cmdString);
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}
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public void runGame() {
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boolean again = true;
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while(again) {
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System.out.println("TODO: do not use that TCPChannel Class");
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try {
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// read user input
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String cmdLineString = userInput.readLine();
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// finish that loop if less than nothing came in
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if(cmdLineString == null) break;
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// trim whitespaces on both sides
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cmdLineString = cmdLineString.trim();
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// extract command
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int spaceIndex = cmdLineString.indexOf(' ');
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spaceIndex = spaceIndex != -1 ? spaceIndex : cmdLineString.length();
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// got command string
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String commandString = cmdLineString.substring(0, spaceIndex);
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// extract parameters string - can be empty
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String parameterString = cmdLineString.substring(spaceIndex);
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parameterString = parameterString.trim();
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// start command loop
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switch(commandString) {
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case CONNECT:
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this.doConnect(parameterString); break;
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case OPEN:
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this.doOpen(parameterString); break;
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case LIST:
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this.doList(); break;
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case KILL:
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this.doKill(parameterString); break;
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case "q": // convenience
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case EXIT:
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again = false; break; // end loop
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default: this.consoleOutput.println("unknown command:" +
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cmdLineString);
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this.printUsage();
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break;
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}
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} catch (IOException ex) {
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this.consoleOutput.println("cannot read from input stream");
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System.exit(0);
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}
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}
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}
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private Map<String, TCPChannel> openConnections = new HashMap<>();
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private void startChannel(String name, TCPChannel channel) {
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channel.start();
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this.openConnections.put(name, channel);
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}
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private void doConnect(String parameterString) {
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StringTokenizer st = new StringTokenizer(parameterString);
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try {
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String remoteHost = st.nextToken();
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String remotePortString = st.nextToken();
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int remotePort = Integer.parseInt(remotePortString);
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String name = remoteHost + ":" + remotePortString;
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this.startChannel(name, new TCPChannel(remotePort, false, name));
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}
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catch(RuntimeException re) {
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this.printUsage(CONNECT, re.getLocalizedMessage());
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}
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}
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private void doOpen(String parameterString) {
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StringTokenizer st = new StringTokenizer(parameterString);
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try {
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String portString = st.nextToken();
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int port = Integer.parseInt(portString);
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String name = "server:" + port;
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this.startChannel(name, new TCPChannel(port, true, name));
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}
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catch(RuntimeException re) {
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this.printUsage(OPEN, re.getLocalizedMessage());
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}
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}
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private void doList() {
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for(String connectionName : this.openConnections.keySet()) {
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System.out.println(connectionName);
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}
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}
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private void doKill(String parameterString) {
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StringTokenizer st = new StringTokenizer(parameterString);
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String channelName = st.nextToken();
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TCPChannel channel = this.openConnections.remove(channelName);
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if(channel == null) {
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System.err.println("channel does not exist: " + channelName);
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return;
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}
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System.out.println("close channel");
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InputStream inputStream = null;
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try {
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inputStream = channel.getInputStream();
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inputStream.close();
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channel.getOutputStream().close();
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}
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catch(IOException e) {
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System.out.println("no open stream yet - kill anyway");
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channel.interrupt();
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}
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System.out.println(".. done");
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}
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}
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