2021-01-06 16:39:45 +01:00

130 lines
4.6 KiB
Java

package dslab.nameserver;
import java.io.InputStream;
import java.io.PrintStream;
import java.rmi.*;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import at.ac.tuwien.dsg.orvell.Shell;
import at.ac.tuwien.dsg.orvell.StopShellException;
import dslab.ComponentFactory;
import dslab.util.Config;
public class Nameserver implements INameserver {
private Registry registry;
private String componentId;
private PrintStream out;
private String registryName;
private INameserverRemote nameserverRemote;
private NameServerRemote nameServerLocal;
private Shell shell;
/**
* Creates a new server instance.
*
* @param componentId the id of the component that corresponds to the Config resource
* @param config the component config
* @param in the input stream to read console input from
* @param out the output stream to write console output to
*/
public Nameserver(String componentId, Config config, InputStream in, PrintStream out) {
this.componentId = componentId;
this.out = out;
// only root nameserver creates RMI registry
registryName = config.getString("root_id");
String registryHost = config.getString("registry.host");
int registryPort = config.getInt("registry.port");
if (this.componentId.equals("ns-root")) {
// Root Nameserver
nameServerLocal = new NameServerRemote("root");
try {
nameserverRemote = (INameserverRemote) UnicastRemoteObject.exportObject(nameServerLocal, registryPort);
registry = LocateRegistry.createRegistry(registryPort);
registry.rebind(registryName, nameserverRemote);
System.out.println("Nameserver bound.");
} catch (RemoteException e) {
System.err.println("Nameserver exception:");
e.printStackTrace();
}
} else {
// Zone Nameserver
String domain = config.getString("domain");
nameServerLocal = new NameServerRemote(domain);
try {
registry = LocateRegistry.getRegistry(registryHost, registryPort);
nameserverRemote = (INameserverRemote) registry.lookup(registryName);
nameserverRemote.registerNameserver(domain, nameServerLocal);
} catch (RemoteException | NotBoundException e) {
e.printStackTrace();
} catch (InvalidDomainException e) {
e.printStackTrace();
} catch (AlreadyRegisteredException e) {
e.printStackTrace();
}
System.out.printf("Zone Nameserver %s started!%n", domain);
}
shell = new Shell(in, out)
.register("nameservers", ((input, context) -> this.nameservers()))
.register("addresses", ((input, context) -> this.addresses()))
.register("shutdown", (((input, context) -> {
System.out.println("shutting down...");
this.shutdown();
throw new StopShellException();
})));
}
@Override
public void run() {
shell.run();
}
@Override
public void nameservers() {
out.printf("Nameservers stored in the nameserver %s:%n", componentId);
List<String> nameservers = nameServerLocal.getNameservers();
out.println(nameservers);
AtomicInteger count = new AtomicInteger(0);
nameservers.forEach(nameserver -> out.printf("%d. %s%n", count.incrementAndGet(), nameserver));
}
@Override
public void addresses() {
this.out.println(nameServerLocal.getAddresses());
}
@Override
public void shutdown() {
// shell is already interrupted
// so just close other things
if (this.componentId.equals("ns-root")) {
try {
registry.unbind(registryName);
UnicastRemoteObject.unexportObject(nameServerLocal, true);
} catch (RemoteException e) {
e.printStackTrace();
} catch (NotBoundException e) {
e.printStackTrace();
}
} else {
this.nameservers();
System.out.println("Zone Nameserver...");
}
System.out.println("Nameserver shut down successfully!");
}
public static void main(String[] args) throws Exception {
INameserver component = ComponentFactory.createNameserver(args[0], System.in, System.out);
component.run();
}
}