jash | linux shell for Operating Systems course | Command Line Interface library

  package com.madhubanti.singleprocess.player.interaction.main;

    import com.madhubanti.singleprocess.player.interaction.initiation.Initiator;
    import com.madhubanti.singleprocess.player.interaction.receiver.Receiver;

    /**
     * Starts application, Instantiate Players and help in garbage collection
     * 
     */
    public class MainApp {

        /**
         * main method instantiates Initiator and Receiver and helps in message
         * communication between them
         * 
         * Also sets unused objects to null and callss System.exit
         * 
         * @param args
         *            String array
         */
        public static void main(String[] args) {
            // Instantiates Initiator
            Initiator initiatorPlayer = new Initiator();
            // Instantiates Receiver
            Receiver receiverPlayer = new Receiver();
            // start sending message
            initiatorPlayer.sendMessage(receiverPlayer);
            // sets the value of the unused instances to null for garbage collection
            initiatorPlayer = null;
            receiverPlayer = null;
            System.exit(0);
        }

    }

    package com.madhubanti.singleprocess.player.interaction;

    import com.madhubanti.singleprocess.player.interaction.initiation.Initiator;

    /**
     * Parent class of {@link Initiator} and {@link Receiver}
     * 
     * @author Madhubanti Jash
     * 
     */
    public class Player {

        /**
         * returns counter value in string
         * 
         * @param counter
         *            1,2,3 etc
         * @return String format of counter
         */
        public String checkCounter(int counter) {
            switch (counter) {
            case 1:
                return "first";
            case 2:
                return "second";
            case 3:
                return "third";
            case 4:
                return "fourth";
            case 5:
                return "fifth";
            case 6:
                return "sixth";
            case 7:
                return "seventh";
            case 8:
                return "eighth";
            case 9:
                return "ninth";
            case 10:
                return "tenth";
            default:
                return "garbage collection";
            }
        }

    }

    package com.madhubanti.singleprocess.player.interaction.initiation;

    import java.util.logging.Level;
    import java.util.logging.Logger;

    import com.madhubanti.singleprocess.player.interaction.Player;
    import com.madhubanti.singleprocess.player.interaction.log.ConfigLogger;
    import com.madhubanti.singleprocess.player.interaction.receiver.Receiver;

    /**
     * Initiates message communication with {@link Receiver} and receives new
     * message from it.
     * 
     * @author Madhubanti Jash
     * 
     */
    public class Initiator extends Player {

        /** initializes logger */
        private static final Logger LOGGER = Logger.getLogger(Initiator.class.getName());

        /**
         * sends message to Receiver and receives new message in return
         * 
         * @param receiverPlayer
         *            instance of Receiver
         * 
         */
        public void sendMessage(Receiver receiverPlayer) {
            ConfigLogger.addLoggerHandler(LOGGER);
            String message = "";
            String prefix = "Sent message for ";
            String postfix = " Time";
            for (int counter = 1; counter <= 10; counter++) {
                message = prefix + super.checkCounter(counter) + postfix;
                LOGGER.log(Level.FINER, "message to be sent is: {0}", message);
                String newReceivedMessage = receiverPlayer.receiveMessage(message, counter);
                LOGGER.log(Level.FINER, "Received new message from Receiver is: {0}", newReceivedMessage);
            }
        }
    }

    package com.madhubanti.singleprocess.player.interaction.receiver;

    import com.madhubanti.singleprocess.player.interaction.Player;
    import com.madhubanti.singleprocess.player.interaction.initiation.Initiator;

    /**
     * Receives message communication from {@link Initiator} and sends back new
     * message
     * 
     * @author Madhubanti Jash
     * 
     */
    public class Receiver extends Player {

        /**
         * receives message from initiator and sends back new message in return
         * 
         * @param message
         *            received message
         * @return newMessage new message to Initiator
         * 
         */
        public String receiveMessage(String message, int counter) {
            String messageForNullValue = "have not received message; so not returning new message.";
            String postfix = " time from Receiver class.";
            String receivedMessage = message;
            String prefix = "Received message for ";
            String checkCounter = checkCounter(counter);
            String counterString = " The counter is: ";
            String newMessage = receivedMessage == null ? messageForNullValue
                    : prefix + checkCounter + postfix + counterString + counter;
            return newMessage;
        }

    }

    package com.madhubanti.singleprocess.player.interaction.log;

    import java.util.logging.ConsoleHandler;
    import java.util.logging.Level;
    import java.util.logging.Logger;

    /** responsible to add log level and handler */
    public class ConfigLogger extends Logger {

        /**
         * parameterized constructor
         * 
         * @param name
         *            A name for the logger
         * @param resourceBundleName
         *            name of resource bundle
         * 
         */
        protected ConfigLogger(String name, String resourceBundleName) {
            super(name, resourceBundleName);
        }

        /**
         * add log level and handler
         * 
         * @param logger
         *            LOGGER
         */
        public static void addLoggerHandler(Logger logger) {
            ConsoleHandler consoleHandler = new ConsoleHandler();
            logger.addHandler(consoleHandler);
            consoleHandler.setLevel(Level.ALL);
            logger.setLevel(Level.ALL);
        }
    }

create function whichcountry(@city varchar(20)) returns varchar(30)
as
begin
declare @return varchar(30)
select @return = 
    CASE @city
when 'New delhi' then 'India'
when 'Mumbai' then 'India'
when 'Dhaka' then 'Bangladesh'
else 'UNKNOWN'
end
return @return
end

select country = dbo.whichcountry(city.city),city *from city
create table city(eno int,
                  ename varchar(20),
                  city varchar(30));

insert into city values(1,'Ray','New Delhi'),
                       (2,'Jash','Mumbai'),
                       (3,'Ravi','Dhaka');