/*
 * kill.java
 *
 * Implementation of the KILL command.
 */
package commands;

import kernel.*;

/**
 * Terminates one or more processes according to the given PIDs.
 * 
 * @author Jan Horky
 */
public class kill extends AbstractProcess {
  /**
   * Realizes the KILL command.
   * 
   * @throws AppException
   *             Exception caused by an error in the virtual machines manager.
   */
  public void realization() throws AppException {
    if (getArgs().size() == 0)
      this.printError("kill: Too few arguments\n");
    else
      for (String arg : getArgs()) {
        int pid = -1;
        AbstractProcess process = null;
        try {
          pid = Integer.parseInt(arg);
          process = getServices().getProcess(pid);
          process.kill();
        } catch (NumberFormatException nfe) {
          this.printError("kill: Invalid argument " + pid + "\n");
        } catch (NullPointerException npe) {
          this.printError("kill: Process " + pid + " doesn't exist\n");
        }
      }
  }

  /**
   * Provides full description of the command to be used in the MAN command.
   * 
   * @return Full description of the command including the syntax.
   */
  public String getHelp() {
    return "\n\nDescription:\nTerminates selected processes according to the given PIDs.\n\nUsage:\n"
        + "kill [PID1 [PID2 [...]]]\n\n"
        + "PID1, PID2, ...\tIDs of the processes to be terminated";
  }
}