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package edu.caltech.nanodb.client;
import java.io.IOException;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
import edu.caltech.nanodb.commands.Command;
import edu.caltech.nanodb.server.CommandResult;
import edu.caltech.nanodb.server.NanoDBException;
import edu.caltech.nanodb.server.NanoDBServer;
import org.antlr.v4.runtime.misc.ParseCancellationException;
/**
* <p>
* This class is used for starting the NanoDB database in "exclusive mode,"
* where only a single client interacts directly with the database system.
* In fact, the exclusive client embeds the {@link NanoDBServer} instance in
* the client object, since there is no need to interact with the server over
* a network socket.
* </p>
* <p>
* <b>Note that it is <u>wrong</u> to start multiple exclusive clients against
* the same data directory!!!</b> Exclusive-mode operation expects that only
* this server is interacting with the data files. For concurrent access from
* multiple clients, see the {@link SharedServerClient} class.
* </p>
*/
public class ExclusiveClient extends InteractiveClient {
private static Logger logger = LogManager.getLogger(ExclusiveClient.class);
/** The server that this exclusive client is using. */
private NanoDBServer server;
@Override
public void startup() {
// Start up the various database subsystems that require initialization.
server = new NanoDBServer();
try {
server.startup();
}
catch (NanoDBException e) {
System.out.println("DATABASE STARTUP FAILED:");
e.printStackTrace(System.out);
System.exit(1);
}
}
@Override
public CommandResult handleCommand(String command) {
return server.doCommand(command, false);
}
@Override
public void shutdown() {
// Shut down the various database subsystems that require cleanup.
if (!server.shutdown())
System.out.println("DATABASE SHUTDOWN FAILED.");
}
public static void main(String args[]) {
ExclusiveClient client = new ExclusiveClient();
client.startup();
client.mainloop();
client.shutdown();
}
}