functions.java

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

/*
 * Functions.java
 * The package functions contains the different class executing the different functions of the FlightSystem Reservation.
 */
package reservation.system.functions;

/**
 * This class uniform the way to call each sub-class (Create, Reserve, Cancel, Lists, Identify) that processes the commands.
 * It delegates to the sub-class the implementation of the function execute () and check ().
 * Also it masks the machinery and helps the developer who want to reuse the program.
 * @author Texier Mathieu and Frederic Bidon
 */
public abstract class Functions extends Object implements reservation.Action {    
    /**
     * Proceed the execution of the request
     * @throws Exception if the excution is not complete
     * @return The apropriate description
     */    
    public abstract String execute () throws Exception;
    
    /**
     * Display the usage for the command (details the different arguments, his type...).
     * @return the Usage
     */ 
    static public String usage (){
        return new String (Create.usage () + "\r\n"
                         + Reserve.usage ()+ "\r\n"
                         + Cancel.usage () + "\r\n"
                         + Identify.usage () + "\r\n"
                         + Lists.usage () + "\r\n"
                         + Store.usage () + "\r\n"
                         + Reload.usage () + "\r\n");
    }
  
    /**
     * Process the array of argument
     * @return the result of the request.
     * @throws Exception If the command is not executed
     * @param arg the list of command to be proceed
     */
    public String execute(String[] arg) throws Exception {
        this.arg = (String[]) arg.clone ();
         _check (arg);
        return execute ();
    }
    
    /**
     * Verify invariants :
     * <PRE>
     * - <CODE>regex</CODE> ^0*[1-9]+0*
     * * - <CODE>arg</CODE> belongs to [min max]
     * </PRE>
     * @return false if the invariants is violated
     * @param min the minimun number allowed in <CODE>arg</CODE>
     * @param max the maximum number allowed in <CODE>arg</CODE>
     * @param arg the input String that will be checked
     */
    static public boolean checkInteger (String arg, int min, int max) {
        if (arg.matches ("^0*[1-9]+0*"))
            return ((Integer.parseInt (arg) >= min) && (Integer.parseInt (arg) <= max)) ;
        return false;
    }

    /**
     * Verify the number of arguments of the command
     * Verify invariants :
     * <PRE>
     * - <CODE>regex</CODE> ^[A-Z][a-z]*
     * - seat < dimension of the flight and > 0
     * </PRE>
     * @param arg the input array that will be checked
     * @param min the minimum argument allowed in <CODE>arg</CODE>
     * @param max the maximum argument allowed in <CODE>arg</CODE>
     * @throws Exception if the invariants is violated
     */
    public static void ArgumentIsValid (String[] arg, int min, int max) throws Exception {
        boolean badFormat = false;
        if (arg != null) {
            for (int i = 0; i < arg.length; i++) {
                if (arg[i] == null)
                    throw new IllegalArgumentException ("The command can not have null parameter\r\n");
            }
            if (arg.length < min || arg.length > max)
                badFormat = true;
        } else badFormat = true;
        if (badFormat) throw new IllegalArgumentException ("The number of argument for this method is not correct\r\n");
    }

    /**
     * Verify that at least one flight is created.
     * @throws Exception if the FlightList contains no flight.
     */
    static void CheckFlightListNotEmpty () throws Exception {
        if (fs.getFlightList ().length <= 0)
            throw new Exception ("Please create a flight first");
    }

    /**
     * Verify that one reservation has been made.
     * @throws Exception if the BookingList contains no BookingNumber.
     */
    static void CheckBookingListNotEmpty () throws Exception {
        if (fs.getBookingList ().length <= 0)
            throw new Exception ("Please reserve for a person first;");
    }
    
    
   /**
    * Check if the arguments are correct and  can be executed
    * @throws Exception if the argument is violated
    */
    abstract void _check (String[] arg) throws Exception;
    
    /**
     * The list of argnument receive from the command
     */    
    protected String[] arg;
}