command.java

This project developed in java leads us to realize a flight reservation system in order to emulate d

/*
 * Command.java
 * The package reservation contains the different class allowing to choose the action to realise.
 */
package reservation;
import reservation.system.functions.*;

import java.util.StringTokenizer;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

/**
 * This class hold Command structure. This object analyse the instruction written by the user and determine according to the first element the command to execute.
 * Then it instancie a new object which depends to the command and which will execute the instruction of the user.
 * @author Texier Mathieu and Frederic Bidon
 */
public class Command implements Mode{
    
    /** Creates a new instance of Command */
    public Command () {
    }
    
    /**
     * Take over the instruction written by the user and also if it want execute the command in Verbose Mode
     * @param in The input stream from which the data are interpreted
     * @param VerboseMode the verbosity level (QUIET, NORMAL, DEBUG)
     */
    public Command (BufferedReader in, int VerboseMode) {
        this.in = in;
        this.VerboseMode = VerboseMode;
    }
    
   /**
    * This method determine the number of element of the user's instruction and analyse the first element of this one.
    * If it corresponds to an available command of the system, it create a new object depending of the command.
    * This new object will execute the instruction with the other elements of the command. 
    */
    public void process () {
        Action action = null;
            boolean escape = false;
        do {
            boolean boolError = false;
            StringTokenizer st = null;
            do {
                try {
                    if (VerboseMode > QUIET)
                        System.out.print ("CMD>");
                    String readLine = in.readLine ();
                    if (readLine == null)
                        return;
                    st = new StringTokenizer (readLine);
                } catch (IOException e){ System.err.println (e);}
            } while (st.countTokens () < 1);
            
            int AgumentNumber= st.countTokens ()-1;
            String line[] = new String[AgumentNumber];
            String Command = st.nextToken ().toLowerCase ();
            
            for (int i = 0;st.hasMoreTokens (); i++)
                line[i] = st.nextToken ();

            try {
                if (Command.equals ("create"))
                    action = new Create ();
                else if (Command.equals ("reserve"))
                    action = new Reserve ();
                else if (Command.equals ("list"))
                    action = new Lists ();
                else if (Command.equals ("identify"))
                    action = new Identify ();
                else if (Command.equals ("cancel"))
                    action = new Cancel ();
                else if (Command.equals ("flights"))
                    action = new Flights ();
                else if (Command.equals ("store"))
                    action = new Store ();
                else if (Command.equals ("reload"))
                    action = new Reload ();
                else if (Command.equals ("exit")) {
                    Functions.ArgumentIsValid (line, 0, 0);
                    escape = true;
                }
                else {throw new Exception ("This command doesn't exist.");}
            } catch (Exception e) {
                System.err.println (e.getMessage ());
                if (VerboseMode > HIGH) {
                	e.printStackTrace ();
                }
                boolError = true;
            }
            System.out.flush ();
            String res = "";
            try {
                if (!boolError && !escape) {
                    res = action.execute (line);
                }
                if (VerboseMode > QUIET)
                    System.out.println (res);
                if (VerboseMode > NORMAL)
                    System.out.println (Action.fs);
            } catch (Exception e) {
                System.err.println (e.getMessage ());
                if (VerboseMode > HIGH)
                    e.printStackTrace ();
            }
            System.err.flush ();
        } while (!escape) ;
    }
    
    private BufferedReader in = new BufferedReader (new InputStreamReader (System.in));
    private int VerboseMode = NORMAL;
}