Create A Class Which When Implemented Requires To Have HashMap And Methods
Oct 13, 2014
I want to make several classes which extend different objects and add additional functions to simplify them and make their purpose in my projects more narrow and make their instances easier to use. So an example, Image class which extends BufferedImage and the constructor in Image class directly loads the file without having to create it first and then have to use Try Catch and all that additional code. Now, here is where my question comes in. Can I make an class, an abstract class or something which can be IMPLEMENTED into these several classes such as the Image class, and in doing so those several classes will have to have (like unimplemented methods) a HashMap<String key, ChildClass instance_as_value>, child class being the Image class as an example.
So I would have something like public class Image extends BufferedImage implements Library, and this class, because it implements Library will have a HashMap<String key, Image value> in it or it's parent class.
i am having a problem while calling a method..i am having a class
Java Code:
public class MySer implements Runnable { public void getMessage(String msg) { ..., }.., } mh_sh_highlight_all('java'); i use the above class in another class
So in the code below I create an instance of my own triangle class and use one of its methods. The thing is I use one of my triangle classes methods in a method other the main method of my main program so I'm thinking it can't access it?
Any way here's the code for my triangle class
import java.util.Scanner; public class QudratullahMommandi_Triangle_06 { Scanner keyboard = new Scanner(System.in); private double side1; private double side2; private double side3;
[Code] ....
and here's the error message
QudratullahMommandi_S_06.java:46: error: cannot find symbol { triangle1.outPut(); ^ symbol: variable triangle1 location: class QudratullahMommandi_S_06 1 error
The one problem in my book was to create a constructor for different shirt features, which I did and ran successfully. Out of curiosity, I also added other methods to see if it would run if the parameters were different from the constructor. It keeps giving me a constructor error. So, my question is, am I able to create a class that uses a constructor with parameters and other methods without errors? I'm guessing there's no reason to since it would be wasted space since the constructor could do it but was just curious if it's possible.
Is everything from the constructor down (in the class) and Shirt.oneShirt (in the main) just a waste of time?
Here's my example:
public class Shirt//class name. { int collarSize;//data field. int sleeveLength;//data field. int pocketNumber;//data field public final static String MATERIAL = "cotton";//final data field for material. public Shirt(int collarSize, int sleeveLength, int pocketNumber)//start of constructor. {
How do I use two constructors and I'm having trouble with using char for gender...
Write a program to test the Person class defined below. Your test program should create two instances of the class (each to test a different constructor) and test each of the methods. You are also required to illustrate the error in trying to access private data members from the client class (for clarity temporarily change the private modifier to public and test again). See screenshots below for sample output.
The screen shots are displayed as:
p1 name = Not Given Age = 0 Gender = U p2 name = Jane Doe Age = 0 Gender = F p1 name = John Doe Age = 25 Gender = M
and
PersonTester.jave:20: name has private access in Person System.out.println("p2 name = " + p2.name + "Age = " + p2.age + "Gender = " + p2.gender); PersonTester.jave:20: age has private access in Person System.out.println("p2 name = " + p2.name + "Age = " + p2.age + "Gender = " + p2.gender); PersonTester.jave:20: gender has private access in Person System.out.println("p2 name = " + p2.name + "Age = " + p2.age + "Gender = " + p2.gender);
3 errors
Here is the class given :
class Person { // Data Members private String name; // The name of this person private int age; // The age of this person private char gender; // The gender of this person
If i have a class(lets say class name is Approval) with the following private members: String recip_id, Int accStat, String pDesc, String startDate How can i create public get and setter methods for these private members of the class?
my query is like: "i want to create hashmaps where the inner hashmap contains the key as firstname and value as a Class Student which contains parameters firstname, lastname,etc. I need this hashmap to be accessed by other objects of different classes".
As we give the values by Scanner, it should be Stored in Hashmap and how those values can be accessed by other object classes?How does the Logic works? What my next step?
How do you declare methods for a class within the class whilst objects of the class are declared else where?
Say for instance, I have a main class Wall, and another class called Clock, and because they are both GUI based, I want to put a Clock on the Wall, so I have declared an instance object of Clock in the Wall class (Wall extends JFrame, and Clock extends JPanel).
I now want to have methods such as setClock, resetClock in the Clock class, but im having trouble in being able to refer to the Clock object thats been declared in the Wall class.
Is this possible? Or am I trying to do something thats not possible? Or maybe I've missed something really obvious?
I am working on a program that simulates a bug moving along a horizontal line, My code works correctly when I test it in it's own class but when I tried testing my constructor and methods in a test class I received an error saying, "package stinkBug does not exist" on lines with my methods. However, stinkbug is not a package.
Java Code:
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */
In the class below I'm trying to create a class that will accept dates in various formats and create a range. The first constructor is easy because I send it the begin date and end date as Date objects. Now I want to send a month(and year) in a constructor and derive the begin and end dates from it. In my constructor that accepts the month/year I need to put the this(startDate, endDate) at the top to be allowed, but the parameters are not built yet.
package com.scg.athrowaway; import java.util.Calendar; import java.util.Date; public class DateRange { private Date startDate; private Date endDate;
For some reason, even though I am giving it the correct number of arguments for the constructor to be initalized it doesn't go through. I end up with a compile error:
PatientBuilder.java:17: error:
constructor Patient in class Patient cannot be applied to given types; Patient aPatient = new Patient(bloodType, rhFactor, ID, age); ^ required: no arguments found: String,String,int,int reason: actual and formal argument lists differ in length
And I'm not understanding how that's possible when it calls for 2 strings and 2 ints and that's what I am passing.
I have this in my main method Scanner inputDevice = new Scanner(System.in);
System.out.println("What is the patients ID number?"); int ID = inputDevice.nextInt(); System.out.println("What is the patients age?"); int age = inputDevice.nextInt();
[Code] ....
And then here are my two constructors, one default and one overloaded.
public Patient() { patientBlood = new BloodData(); ID = 0; age = 0; bloodType = "O"; rhFactor = "+";
How to implement a RequestDispatcher, so I checked tomcat's source code, the ApplicationDispatcher class, but there are many places I can't understand.
I found in the ApplicationDispatcher class that the method used to forward request and response to the designated resource is the invoke(ServletRequest,ServletResponse) method, and this part is responsible for executing forward:
support.fireInstanceEvent(InstanceEvent.BEFORE_DISPATCH_EVENT, servlet, request, response); // for includes/forwards if ((servlet != null) && (filterChain != null)) { filterChain.doFilter(request, response); } // Servlet Service Method is called by the FilterChain support.fireInstanceEvent(InstanceEvent.AFTER_DISPATCH_EVENT, servlet, request, response);
I can't understand this part of code, does this mean the RequestDispatcher.forward() and RequestDispatcher.include() methods are all executed in a filterchain? What is the mechanism of it?
I have attached a picture. I am struggling to understand one of the errors. It says it requires an int and a string. I have put a number in but I don't understand the string part!
How to create object for "class B" and call the "function_B" from other different class D where class D has no connection with class A? Here is my program.
public class A(){ void print(){} } class B{ void function_B(){} } class C{ void function_C(){} }
Here, A, B, C are in the same package. But class D is in different package.
I have to make two classes. The first one crates an instance of an array of several integers and prints data (average, greatest, lowest, et cetera) based on the second class, which contains the methods. I'm having a problem with the syntax for the first class required to use the methods.
Here's a shortened version of what I have right now just based on processing the number of integers in the array (because if I can get just one method properly connected, I could figure out everything else).
Driver
import java.util.Arrays; public class ArrayMethodsDriver { //Creates the ArrayMethods object public static void main(String[] args) { int[] a = {7,8,8,3,4,9,8,7};
[Code] ....
When I try to compile this, I currently get the "class expected" error on the count part.
Design a class named Person and its two subclasses named Student and Employee. Make Faculty and Staff subclasses of Employee. There is also a MyDate class as explained below. A person has a name, address, phone number, and email address. A student has a status (freshman, sophomore, junior, or senior). Define the status as an integer which can have the value 0 (for "Freshman"),
1 (for "Sophomore"), 2 (for "Junior"), and 3 (for "Senior"),
but don't allow the status to be set to any other values. An employee has an office, salary, and dateHired. The dateHired is a MyDate field, which contains the fields: year, month, and day. The MyDate class does not explicitly inherit from any class, and it should have a no-arg constructor that sets the year, month, and day to the current year, month, and day. The MyDate class should also have a three-argument constructor that gets three int arguments for the year, month and day to set the year, month and day.
A faculty member has office hours and a rank. Define the rank as a String (for values like "Professor" or "Instructor"). A staff member has a title, which is also a String. Use data types for the fields as specified, or where one is not specified, use a data type that is appropriate for the particular field. Write a test program called TestEveryone.java that creates a Person, Student, Employee, Faculty, and Staff object, and invoke their toString() method (you don't need to call the objects' toString() method explicitly).
Note: Your MyDate.java class is the object class that your dateHired field is created from in the Employee.java class.
Do not use the Person, Employee or Faculty classes defined on pages 383 and 384 of the book. Create new ones.Here is the code I have so far concerning the employee and MyDate.
public class Employee extends Person { private String office; private double salary; //private MyDate dateHired; //7 argument constructor for employee public Employee(String name, String phoneNumber, String email, String address, String office, double salary /*MyDate dateHired*/) { super(name, phoneNumber, email, address);
The assignment is to create a SmartString class that implements a SmartStringInterface class (created by professor) and implements a few methods. We are basically taking a string and then taking various substrings and inserting, deleting them and undoing changes as well. Here are the methods in the interface to use along with the parameters.
public interface SmartStringInterface { public void insert(int pos, String sstring); public void delete(int pos, int count); public void undo(); public String toString();
The Undo is supposed to be able to be called multiple times (to be tested using a driver program that we must create) but the part that's got me is that the changes are only supposed to be stored. Currently, I am storing the "new" string after each change onto a stack, so that undo can just pop off the stack and it will revert to the previous string. Professor said that was wrong, so I don't know how to do it. Here is what I have so far (some of the code we have is using default StackADT stuff from our book, so if you need that I can post as well. You can see in the undo method where I currently save the string. We can use multiple stacks if needed, but the less the better. Must use at least 1. The exception code is already coded for us in another file also. I am only having to code these methods and the driver to test.
import java.util.Arrays; public class ArrayStack<T> implements StackADT<T> private final static int DEFAULT_CAPACITY = 100 private int top; private T[] stack;
I am doing a homework assignment and I am clueless as to what I did wrong or supposed to do in terms of placement of coding. If someone could dumb down their response and tell me what I did wrong
This is what I supposed to do:
1.) Type the following shell for the class:
public class ParadiseInfo { }
2.) Between curly braces of the class, indent a few spaces and create the shell for the main() method:
public static void main(String[] args) { }
3.) Between the braces of the main()Method, insert a call to the displayInfo() method:
displayInfo();
4.) Place the displayInfo() method outside of the main() method, just before the closing curly brace for the ParadiseInfo class:
public static void displayInfo() { system.out.println ("Paradise Day Spa wants to pamper you."); system.out.println ("We will make you look good."); }
This is what I attempted to do: I know it is wrong I am just clueless on where to put the code and why
public class ParadiseInfo { displayInfo(); public static void main(String[] args) { public static void displayInfo(); } system.out.println("Paradise Day Spa wants to pamper you."); system.out.println("We will make you look good."); }
--- Update ---
I have also tried this:
public class ParadiseInfo { displayInfo(); public static void main(String[] args) { } public static void displayInfo(); {
[Code]...
The very last attempt I only ended up with one error which is:
import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicInteger; import java.util.concurrent.locks.Condition; import java.util.concurrent.locks.Lock; public class tree_lock_test{ int total_instances; int thread_instances = 0; int N;
[Code] .....
this is compiled with another Peterson class which has implemeted peterson lock for two threads ...
I am doing an assignment and I am clueless as to what I did wrong or supposed to do in terms of placement of coding.
This is what I supposed to do:
1.) Type the following shell for the class:
public class ParadiseInfo { }
2.) Between curly braces of the class, indent a few spaces and create the shell for the main() method:
public static void main(String[] args) { }
3.) Between the braces of the main()Method, insert a call to the displayInfo() method:
displayInfo();
4.) Place the displayInfo() method outside of the main() method, just before the closing curly brace for the ParadiseInfo class:
public static void displayInfo() { system.out.println ("Paradise Day Spa wants to pamper you."); system.out.println ("We will make you look good."); }
This is what I attempted to do:
I know it is wrong I am just clueless on where to put the code and why
public class ParadiseInfo { displayInfo(); public static void main(String[] args) { public static void displayInfo(); } system.out.println("Paradise Day Spa wants to pamper you."); system.out.println("We will make you look good."); }
--- Update ---
I also tried it this one and ended up with 1 error..
public class ParadiseInfo { displayInfo(); public static void main(String[] args) { } public static void displayInfo(); { system.out.println("Paradise Day Spa wants to pamper you."); system.out.println("We will make you look good."); } }
