store.java

来自「This project developed in java leads us 」· Java 代码 · 共 62 行

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

import java.io.*;

/**
 * This class hold Create structure. This object allows to create a new flight in the data base by calling the method <CODE>create</CODE> in {@link reservation.system.FlightSystem}.
 * @author Texier Mathieu and Frederic Bidon
 */public class Store extends Functions {
    
    /**Name of the file where we want to save the data.*/
    private File datafile;
    
    /**
     * Verify invariants :
     * <PRE>
     * - Argument not null
     * - The number of argument equals 1
     * - File's name doesn't exist
     * - The file can be created
     * </PRE>
     * @throws Exception if the file exists or cannot be created.
     */
    void _check (String[] arg) throws Exception {
        CheckFlightListNotEmpty ();
        ArgumentIsValid (arg, 1, 1);
        File datafile = new File (arg[0]);
        if (!datafile.exists ()) {
            if (!datafile.createNewFile ())
                throw new Exception ("Cannot create the file: " + datafile.getPath ());
        } else
            throw new Exception ("file " + datafile.getPath () + " already exist");
        
        this.datafile = datafile;
    }
    
    /**
     * Display the usage for the command <CODE>reload</code>.
     * @return the usage.
     */
    static public String usage() {
        String usage = " Usage command Store: store <fileName>\n\r";
        usage += " - The <fileName> is the path to the file to be store \n\r";
        usage +=" The file extention is .out .\n";
        return usage;
    }
    
    /**
     * Store in a file the data contained in the database.
     * @throws Exception if the file is not saved.
     * @return a confimation's message if the data are stored.
     */
    public String execute () throws Exception {
        ObjectOutputStream fout = new ObjectOutputStream (new FileOutputStream (datafile));
        fout.writeObject (fs);
        return "Flight stored";
    }
}