design a class to conduct a survey of three hospitals. you want to know how many sectors (eg operation, children, gastronomic) each hospitals have, and how many doctors there are in each sector.
what is the process of class design?
I'm currently taking a computer program design class which has done a lot for my understanding of how to organize classes, but isn't giving me challenging enough assignments and I don't believe it's going to be covering interfaces and abstract classes, which is a shame. So I've been digging into these topics myself and decided to work on my own program (an Uno game program) that would utilize everything we've been learning and give me some practice with GUIs.
My current plan:
Have an abstract UnoCard class that determines the basic properties/methods common to all cards. Create a class for each card type extending from UnoCard, which would be - the generic card (number and color), action cards (skip, reverse, draw two), and special cards (wild, wild draw four, and blank).
Two enums, one for color, one for rank (which includes the numbers, as well as the action and special card ranks (reverse, wild, exc.) ).
A deck class would have an ArrayList <UnoCard> property and it's constructor would initialize a fresh deck.
A hand class that also has an ArrayList <UnoCards> where it gets said cards from the deck class.
A discard pile class, which contains the cards discarded and the current card in play.
A "board" class (haven't figured out a better name for it yet) which would determine/keep track of the number of players/hands, the turn order, the locations of the cards, and the winning condition.
Area of confusion and concern I'm having:
From what I've read, I want to avoid circular dependency. So if that's the case, when a card type effects the state of a "hand" or the turn order or really anything else, then in what class do I place the method(s) that effect that? If I place it in the specific card class, wouldn't that create a circular dependency? So would it be better then to have the hand class figure out what can be done with a specific card and what that specific card effects (which wouldn't that hinder the cohesion of the class?)?
I was also thinking a possible solution might be to have the non-generic card types contain methods that return values as apposed to manipulating higher level classes, such as a boolean drawCards which returns true if cards need to be drawn, false otherwise (same for skip, reverse, exc.).Then maybe the board class can determine what to do if those values are true or false (which actually seems more convoluted since only one value would be allowed to be true at any given time).
The other solution I was considering is to have a single UnoCardRules class, which serves the sole function of providing methods to determine the effects of each card, that way each card class can only worry about defining the card's state.
How do you call classes within other classes? Or can you only call classes through the main?
View Replies View RelatedI was reading head first java and the author told to read head first design pattern next.
View Replies View Relatedwe have been given a scenario to design a system in which we have to make the class diasgrams. however we have to use appropriate patterns that match the scenario.
View Replies View RelatedI am designing an application I want to know what are the best technology Like Java FX for front end design?
View Replies View RelatedBasically I have to enter 5 numbers that I put through a loop and they print the star * depending on the number.An example would be this 5:*****. However, my codes prints out 5:*; 5 times. How to correct my code
Java Code:
import java.util.Scanner;
public class IntegerOutput
{
public static void main( String args[] )
{
Scanner input = new Scanner( System.in );
int num1;
int num2;
int num3;
int num4;
int num5;
[code]....
I have done this a few times but I want to make sure I am doing it correctly. In other words creating a clean understandable program. Instead of posting code I will just talk about this is my plan:
Create a model (getter and setters)
Create a view (via swing)
Create a controller (pass the model and view in the parameter)
Database DatabaseConnection:
Use the singleton pattern
Database:
Create an interface called Database with all the queries I will need (insert, delete etc)
Create a class called DataBaseDAO and implement the interface database and get an instance of the DatabaseConnection.
Tying it all together:
In the controller should I use the "new" operator and create a new database class or extend the database class? I am thinking I should not do it in the controllers constructor but make a field if I use the "new" operator like:
private Database db = new Database();
Create a class called App
Create a new Model
Create a new View
Pass the view and model into the controllers parameter.
Am I on the right track? Is this messy? Is there a better way of doing it?
I have a class as shown below. This class has a method addFilter with 2 parameters (type String and type Command1 )
public class Command1 {
public StringBuffer addFilter(String query, Command1 dataBase) {
//concrete implementation
return query;
}
}
I have another class Command2. Here I need a similar method. The only difference is in the type of parameters passed. (type String and type Command).
public class Command2 {
//TO DO:
public StringBuffer addFilter(String query, Command2 cmd) {
//concrete implementation
return query;
}
}
I have started by using Interface
public interface Helper {
public StringBuffer addFilter(String query, XXXXX parameter2);
}
I would like the classes Command1 and Command2 to implement the interface Helper and override it these two public classes.
However my problem is in dealing with the 2nd parameter. Am I right in my approach? How do I handle this issue?
I need selecting which design pattern to use in my case.
I am creating a list of objects "items" to be presented in a list for the user to choose from, all objects have a title and a check box. Some objects have additional textbox for user input, some objects have additional image for illustration, and some objects have additional textbox and image as well.
I read and saw online videos but not sure if my selection "Factory Design Pattern" is the best match.
I'm doing an aggregation exercise that's suppose to find the volume and surface area of a cylinder. What I'm trying to do is pass values from one class, to a second class, and that second class passes values to a third class.
This may be a clearer explanation: The first class is the main program which sends values to the second and third class. The second class is used do calculations for a circle (a pre-existing class from another assignment). The third class grabs the values that the second class calculated and calculates those values with the one that was passed from the first class to the third class. The first class then prints the outcome.
Problem is when the program gets to the third class, it just calculates the value from the first class with the default constructor from the second class. It's like the second class never received the values from the first class. I think I'm missing a step, but I don't what it is.
First Class:
package circle;
import java.util.Scanner;
public class CylinderInput
{
static Scanner in = new Scanner(System.in);
public static void main(String[] args)
{
//user defined variable
[Code]...
I am completing the exercises in Java How To Program 8th Edition by Harvey and Paul Deitel.There are two optional exercises GUI and Graphics Case Study Exercises on page 141 Chapter 4.
I have to use loops and control statements to draw lines thereby creating two designs.I am trying to create the design on Fig. 4.20. The lines do not line up correctly.The lines should fan out from all corners. Individually, they look exactly like it should.
Example of one corner.
int width = getWidth();
int height = getHeight();
// upper-left corner
int startX = 0;
int startY = 0;
int endX = 0;
[Code] ....
For the other corners I have different starting and ending positions.To draw upper-left corner I have a starting position of 0,0 and ending position of 0,height.I then move ending position up one vertical step and right one horizontal step. I repeat this fifteen times.
To draw upper-right corner I have a starting position of width,0 and ending position of width,height. I then move ending position up one vertical step and left one horizontal step.
To draw bottom-left corner I have a starting position of 0,height and ending position of 0,0. I then move ending position down one vertical step and right one horizontal step.
To draw bottom-right corner I have a starting position of width, height and ending position of width,0. I then move ending position down one vertical step and left one horizontal step.
For the second design Fig. 4.21 all my lines line up correctly no matter the direction I resize it. Both designs frame size is 250,250. Both designs are divided into fifteen steps.
Design Patterns are one form of reuse. so is inheritance. what are the similarities and difference between them?
View Replies View RelatedI am trying to design properly a simple 1to50 game (yes, the one that is so popular among mobile apps), but as a web application that allows two player games. I tried to document myself on the technologies I could use and came to the decision that some kind of Java would be suitable. I know that HTML, HTML5, CSS, JavaScript are client side languages with what I can basically design the client application that runs on a web browser. I installed Tomcat web server, configured Java Servlet API, done some research on Servlets and JSP, but I still cannot really imagine how all of this can work. Servlets form the Controller, JSP files the Model? How can I make them communicate, how can Servlets "tell" JSP files what to dynamically generate? Can JSP files communicate with JavaScript? Is JavaScript even necessary?
I thought that this question is not basically about a specific thing regarding JSP or Servlets, more about design and general concept, that is why I put this question under beginning Java.
I was told to design a class named Rectangle to represent a rectangle.The class contains:
■ Two double data fields named width and height that specify the width and height of the rectangle. The default values are 1 for both width and height.
■ A no-arg constructor that creates a default rectangle.
■ A constructor that creates a rectangle with the specified width and height.
■ A method named getArea() that returns the area of this rectangle.
■ A method named getPerimeter() that returns the perimeter.
Draw the UML diagram for the class and then implement the class. Write a test program that creates two Rectangle objects one with width 4 and height 40 and the other with width 3.5 and height 35.9. Display the width, height, area,and perimeter of each rectangle in this order.Here is my code for the Rectangle Class:
class Rectangle
{
double width;
double height;
public Rectangle() {
width = 1;
height = 1;
[code]....
The error that I am given when I compile the driver is as follows:constructor Rectangle in class Rectangle cannot be applied to given types; required: no arguments; found:int,int; reason: actual and formal argument lists differ in length.
I've looked over the concepts of Java programming, tested them in code and i understand most of them. I have a problem when i need to make harder programs , this might be because i dont know design patterns and algorithms.I'm curious what a entry level programmer needs to know to get a job in the field. Right now i was thinking i need to know:
1. The way all big concepts work and most of the keywords.
2. Design patterns.
3. Algorithms.
what i actually need to know for an entry level job and can you tell me which design patterns and algorithms are a must know for that first job. Considering i might have financial problems in the near future this is not a theoretical question, i really need to know what i need to learn in the next 2-3 months to get an entry level job down.
I am working on a Project of Ecommerce Shopping WebSite in Java.
First I Decided to use Servets,JSP,Spring,hibernate etc.. from Scratch to design its Layouts and Functionality.
But After Reading this Thread [URL]...
I Found that there are already some Ecommerece Solution that are availabale in Java Like Magento.
Is it worth To use these Ecommerce Solution for Development Purpose of Premium Purpose.
I read that some of them are Open Source.
If a ShoppingCart Solution is OpenSource then Can We Use that to develop and Distribute for Premium Purpose?
I need to get Windows application made. Is there a graphical, drag&drop layout tool in which I can place 'controls' such as buttons, panels, toolbars onto a window then write the code to respond to them? It seems to be common place in other systems.
View Replies View RelatedHere is an example of a GUI. Is it possible to make this kind of a thing using Java Swing? Is it possible to have a picture on the entire background of the JFrame, and then other Swing components like buttons, labels etc. sitting on it?Is it possible to have action listeners behind pictures? In other words, they will behave like buttons: the user clicks on them and they do something.
View Replies View RelatedI have to create a Swing application for which i haved a set of requirements as,
1. there will be two JPanels ,left and right, on the main JFrame , left frame would contain a JTextField and a submit JButton ,user can enter values 1,2,3 ,in the JTextField and presses the JButton
a. if user enters 1, a JTextField will be shown on right JPanel
b. if user enters 2, a JTextField and a JRadioButton will be shown on right JPanel
c. if user enters 3, a JTextField and a JComboBox will be shown on right JPanel
So I have done that but when my boss sees the code behind this application he told me to make it more extensible i.e. if there is going to be an additional requirement for values 4 or 5 or 6 and so on , then i have to make minimal changes in my code or no change in my code and it should work . how this can be done ? is it possible make such software design ?
public class DesktopApp extends JFrame {
private static final long serialVersionUID = 1L;
private static final Logger logger = Logger.getLogger(DesktopApp.class);
private JPanel jp, jp2, mainPanel;
private JLabel jl, jl1, jl2, jl3, jl4, jl5;
private JTextField jText, jText2, jText3, jText4;
[Code] ....
What wrong am i doing here in this code which in not considered to be an extensible design ?
I'm working on a consulting training project to create a eCommerce online shopping application. Nothing big, just something functional and simple. That's why I want to structure it with the easiest maintainability possible. I've already ironed out the the database entities and how they'll relate to one another and even managed to establish connection to the database from my java application class. NOW I need to configure a user session on the web.xml, from what I've learned so far in my consulting, I can easily use jsp and servlets to have httpsession objects receive and send the information needed to and from the database, but the question is, how many do I need for a client's session?
Would maintainability be easier if I divide each entity's class actions to different servlets(a customer servlet, order servlet, product servlet, etc...), or can a single servlet handle an entire session without any complication?
I have a project about programing a game in java . In this project you are required to design and implement a word guessing game. In the game, user selects one of the available dictionaries (animals, plants, technical, names, etc. ), and the program randomly chooses one word from that dictionary and displays it by scrambling the letters. The user tries to guess the word while a guess counter starts to count down (lets assume it starts from 5).
While counter counts towards zero, the program chooses -randomly- two misplaced letters and puts them into correct positions to reveal the word more and give the user a hint. However, giving a new hint reduces the total value of the question. Lets say if the initial value of the question is 500 when all letters are scrambled, it reduces to 400 after 1st incorrect guess and hint, then after every incorrect guess it reduces more. You can determine the value of the question by the length of the word. The other details of the game is as follows:
1.You must design at least three classes (for example game, scrambledword, and dictionary).
2.Dictionaries are written in text files. If you design a class for dictionary, it must be constructed by a user chosen category ((animals, plants, technical, names, etc). In the constructor, the dictionary text file corresponding to this category must be opened and read; and words in that dictionary must be read into memory (e.g. String array). You must submit your dictionaries with your code. Do not share dictionaries between friends.
3.The game will record your total points and name in a text file where a hall of fame which has different users and their total points in 10 questions. You can design and implement a class for this.
4.Bonus+5%: Put user interface modules textboxes, buttons, etc Or
a.Use class hierarchy
b.Use of thread and timers and reducing the question value by timer instead of guesses.
I want to design an open-answer quiz game using Java. Basically, the plan is to design a quiz where the name of a medicine is displayed as "the question" and the player will need to input the unique code (as "the answer") of the medicine in an open box (all the codes are two characters). The list has about 204 named medicine (with potentially more to be included at a later stage). The questions will not appear in the same order for each session restarted; they will appear randomly.
The player will have 60 seconds, and for each correct answer, will score 1 point and add 2 seconds to the timer. The player will also have 6 "lives", and for each incorrect answer, the player will lose a life, with no effect on the time.The idea of the game is to support the player memorise as many of these medicine codes as possible. How this can be achieved from total grassroots.
For example
Select food;
1. hamburger 2. pizza 3.chicken 4.sandwich .. etc
if I choose hamburger there are choices again
1. big mac 2.Quarter Pounder with Cheese 3.Double Cheeseburger ...etc
If I choose big mac there are choices again!!.
choose the drink you want
1.coke 2.orange juice ..etc
situations like this, what design pattern should I use?
it may reflect some of those changes that happened after you created the iterator but there is no guarantee. I think the state changes that take place after you start iterating are never reflected. But these are implementation details. As such we know that iterating through a ConcurrentHashMap may not give us the most recent updates that happened to the Map ( the ones that happened after we created the iterator ). We would use it if we either don't care about missing some of the updates or if we know that such updates are not likely and we want maximum concurrency in that kind of a setting.
This isn't the case with the iterator returned by a LinkedHashMap or a synchronized view of a LinkedHashMap.There are some small but significant incorrect things I have said in my response. Here is a better response.It may reflect some of those structural changes that happened after you created the iterator but there is no guarantee. I think the state changes that take place after you start iterating are never reflected. But these are implementation details. (This is an just an untested observation. Not even an implementation detail. As such we know that iterating through a ConcurrentHashMap may not give us the most recent structural updates that happened to the Map ( the ones that happened after we created the iterator ). We would use it if we either don't care about missing some of the structural updates or if we know that such updates are not likely and we want maximum concurrency in that kind of a setting.
I've since been looking at the new TableView class made available via JavaFX from this Oracle tutorial here. It looks like I can do the following:
1) Create a POJO class that contains the columns as properties of the class. Each object of the class represents a row.
2) Create a TableView class that contains a list of the new POJO class from 1) above. Any insertion of additional POJO class from 1) represents a new row inserted into the TableView class and this gets reflected immediately and automagically on the JavaFX GUI.
This is all great! But how do I do the following:
1) Access a specific cell in the table via a row name and col name?
2) Return all cells in a column as an array, by specifying the col name?
3) Have more than one GUI data binded to this TableView?
4) Specify the POJO class dynamically at run time? If I want to create an interface (say a web service) that allows someone to add columns, remove columns, etc at run time and this needs to be reflected both internally in memory and externally on all the connected GUIs?
When it comes to Java EE I see many developers having trouble with the usage of transactions and exceptions and when to use what.
I see a full chapter of RESTful Web Services, but do you also relate these Web Services to their counterparts (SOAP Web Services)?