Magne.Qvarme
lab3

Repository

Command command = this.allCommands.get(commandName);
if (command != null) {
  String result = command.run(args);
  return result;
} else {
  return "Command not found: \"" + commandName + "\"";
}
package no.uib.inf101.terminal;

public interface Command {

}
String[] args = new String[] { "foo", "bar" };
String result = command.run(args);
String run(String[] args);
String getName();
private final HashMap<String, Command> allCommands = new HashMap<>();
this.allCommands.put(command.getName(), command);
SimpleShell shell = new SimpleShell();
shell.installCommand(new CmdEcho());

Terminal gui = new Terminal(shell);
gui.run();
Command command = this.allCommands.get(commandName);
if (command != null) {
  return command.run(args);
} else if (/* ... */) {
  // ...
} else {
  return "Command not found: \"" + commandName + "\"";
}
default void setContext(Context context) { /* do nothing */ };
command.setContext(this.context);
package no.uib.inf101.terminal;

public class HelloWorld {
  public static void main(String[] args) {
    System.out.println("Hello World!");
  }
}
package no.uib.inf101.terminal;

import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import java.lang.reflect.Method;
import java.nio.charset.StandardCharsets;

public class CmdJavaProgram implements Command {

  private final Class<?> mainClass;
  private final String commandName;

  /**
   * Create a command from a Java program. Programs that read from
   * standard input are not supported, but printing to standard
   * output (i.e. using System.out to print) is ok.
   *
   * @param commandName  The name of the command
   * @param mainClass  The class containing a main(String[]) method
   */
  public JavaProgram(String commandName, Class<?> mainClass) {
    this.mainClass = mainClass;
    this.commandName = commandName;
  }

  @Override
  public String getName() {
    return this.commandName;
  }

  @Override
  public String run(String[] args) {
    // Remember original System.out and System.err
    final PrintStream orgOut = System.out;
    final PrintStream orgErr = System.err;

    try {
      // Prepare for capturing the output of the program
      ByteArrayOutputStream out = new ByteArrayOutputStream();
      PrintStream newOut = new PrintStream(out, true, StandardCharsets.UTF_8);
      System.setOut(newOut);
      System.setErr(newOut);

      // Invoke  main method of the class for which this command was created
      Method main = this.mainClass.getMethod("main", String[].class);
      main.invoke(null, new Object[] {args});

      // Convert the captured output to a string and return it
      return out.toString(StandardCharsets.UTF_8);
    } catch (NoSuchMethodException e) {
      return "No main method found in class " + this.mainClass.getName();
    } catch (Exception e) {
      return e.toString();
    } finally {
      // Restore the original System.out and System.err
      System.setOut(orgOut);
      System.setErr(orgErr);
    }
  }
}
shell.installCommand(new CmdJavaProgram("hello", HelloWorld.class));
shell.installCommand(new CmdJavaProgram("new", Main.class));