Data Type That Can Store Methods
Mar 21, 2015I was wondering is there any data type that can store method?
View RepliesI was wondering is there any data type that can store method?
View Repliespublic class InputFileData {
/**
* @param inputFile a file giving the data for an electronic
* equipment supplier’s product range
* @return an array of product details
* @throws IOException
*/
public static Product [] readProductDataFile(File inputFile)
throws IOException{
// YOUR CODE HERE
}
This code is meant to be used to read a text file and store the data in an array of type Product[]. I know how to read in a text file and have it sort it into an array, but I've never seen code laid out in this fashion before (specifically "public static Product[]", and I'm unsure how to work with "(File inputfile)". I've looked all over the place but can't find any examples of anything like this.
Also, the code given cannot be changed, as it's that code I have to work with.
I still don't understand how to use it as a whole. For example, do I read the file in the main and have this method read that in and output to the Product class? Do I read the file in this method? I can't work out how to make this work when I have to use this method.
This isn't solely related to java.awt.Color, it's more of a question on how to store methods or redirections to use methods on any value passed in. To explain my question I'll describe a scenario:
ClassA is an instanstiatable class
ClassA has an instance of ClassB called cB
ClassA has methods of affecting cB
ClassD is also an instanstiatable class
ClassD has an Array[x][y] of instances of ClassA
I want to create a ClassE which I would initiate it with references to ClassA's methods or their actual methods and then I can use ClassE to easily transform ClassD's instances of ClassA by the same methods.
What I'm actually doing:
I made a class called GameColor, it has methods like changeHue, setRed, setHue, changeBrightness, setSaturation etc, these methods affect an instance of java.awt.Color in the GameColor class instances, so like they can change the hue or set it with changeHue or setHue etc...
Now I want to do something like perform a single method on a whole BufferedImage, on each of it's pixels RGB. So, I'm thinking of creating a GameColorEffects class which I store references or actual methods of GameColor like changeHue, and then I use GameColorEffects somehow to change a whole BufferedImage more efficiently, what's the most efficient way I can store methods or their reference of GameColor and then later apply them on each pixel of a BufferedImage using GameColorEffects. So all I do is initiate GameColorEffects with methods or reference from GameColor, and then I can apply it to easily transform each pixel.
in my progrm there are three diff array of objects...namely garments..gadgets and home app...now one who buys from each of these sections will have to make a bill at last...when he choses to make the bill he will be shown the list of products he bought and their details (like price...brand...etc)...so i thought that while he orders each product(which is done in a previous method called purchase()...)....(each product is stored as an object in there diif arrays namely garments...gadgets ...appliances)....each of those object will be copied in a new array in a diif class...then that array print will give me the desired result...
is this approach correct...?and if its correct then how can i pull out a specific obj frm a stored array of object and then save it in a new array....?
method passing null to the called function, compiler would take that parmer as what type of paramer???
View Replies View RelatedI am new to Java programming and how to store data in Java.....Here is a example:Unique number, description, qty in box, price...There are thousands of these in my list. What would be the best way to store them.
View Replies View RelatedI have a java query like this
query ="Select major_career.Major_Title, career.ISCOTitle,career.FS.... " //only partial,
// I swear the query is correct
resultSet = statement.executeQuery(query); //this executes it
relArr = new ArrayList<String>(); //don't worry it is intialized
In the code below I tried to store the resultset components into the arraylist
int j = 1;
while (resultSet.next()) {
while(j<=numberOfColumns){
relArr.add(resultSet.getObject(j).toString());
j++;
}
} // end while
I am not sure whether the arraylist is able to store the result set because when i try to display it like show below it only shows some rows and only the first column
Iterator it = relArr.iterator();
while (it.hasNext())
{
System.out.println(it.next());
I want to manipulate the resultset results in my program by copying the resultset values to other datastructures.
I am making a program to read data from excel files and store them in tables by their IDs. I have managed to read all the data from excel files as a string and store them in a table. But my project is to store them in table by ascending IDs. I have created the comparator in another class but when i call it in the main class nothing happened. The data that I have to store is like the below:
ID Name Salary
50 christine 2349000
43 paulina 1245874
54 laura 4587894
23 efi 3456457
43 jim 4512878
The codes are below:
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
[URL] ....
Basically I'm trying to code this program but I keep getting error can't be applied to given types. I know it has to do with my method trying to be called by an array, but I'm just kinda lost.
Write a program that prompts the user to input cash amounts and use a method to calculate the average amount for a week given 7 inputs of daily cash intake amounts for a cash register. Use an array to store the values. Recall that average is the sum of the values divided by the number of values. The method should take argument(s) of type double and return average weekly cash amount as a double.
Make sure you test your program using the test data given below and calls the averageCash() method defined above passing in the values. Verify that the input values are greater than or equal to 0. Negative numbers are not allowed. Output the values used and the averageCash value.
import java.util.*;
public class ArrayHandout {
public static void main(String args[]) {
int[] a=new int[6];
Scanner sc=new Scanner(System.in);
[Code] ....
Generic methods are methods that introduce their own type parameters. This is similar to declaring a generic type, but the type parameter's scope is limited to the method where it is declared. Static and non-static generic methods are allowed, as well as generic class constructors.
1. The method is only exclusively to be used for the declared argument parameter? For example given a generic method:public static <String, Integer> boolean method(Pair<K, V> p1) {}I could only invoke the method if Pair argument parameter is <String, Integer>?
2. Or, it will return a <String, Integer> value?
I am able to perform column operation but not able to perform row operation because i am not able to store data say a 2 matrix [][]. I need to store the data into a 2-D matrix. Here is my code:
Java Code:
import java.awt.List;
import java.io.BufferedReader;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Scanner;
public class colRowRead {
[Code] ....
I tried something like that:
for(int i=0; i<rows; i++) {
for(int j=0; j<cols; j++){
matrix [i][j]=textFile.get(i).split(" ");
//System.out.println(matrix[i][j]);
}
}
*/ mh_sh_highlight_all('java');
File col.txt is like this:
Java Code:
5 9 7 1 5
3 6 8 6 8
4 6 7 8 9
9 8 3 5 7 mh_sh_highlight_all('java');
i am newbie to servlet and m working on a project like online shopping. I have list of data items in my database and i am able to fetch and display the data from database but i want to know that how can i store these data items in ServletContext so that i can use use it frequently in other pages.
View Replies View RelatedI am trying to develop a new web application which takes in data from a form and stores data in a database.I have included all the three files join.jsp(the form which takes in data),reg.java(servlet) and JavaConncetDb(method which connects db and servlet). I get a 404 error when i try load the web application.
My file structure in eclipse
The error I am getting
join.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
[Code] .....
I want to create few forms in our project. I searched in web, All are PHP form Generator only not for any JSP. I could see one JSP form Generator Site. But the Content will store it in their Server. How to create Feedback form in JSP which will store the Data in Database directly.
View Replies View RelatedHow i can get the data from a file, for a key that have multiple values without using split method and i want to store that data in an array
file name:"new.txt"[contains below data]
Name=google.com, yahoo.com,facebook.com
Attachment=abc1,abc2,abc3
I am successfully able to do this using following code
Properties props = new Properties();
String configFilePath = (Cjava_confignew.txt);
props.load(new FileReader(configFilePath));
String TestName = props.getProperty(Name);
String test[] = TestName.split(,);
Now i just want to store the values for key "Name" in array without using TestName.split(,); but i am not able to do this.
I have also used .yml file to avoid this but did not succeed, some way to do this
file name test.yml
Name
-google.com
-yahoo.com
-facebook.com
Attachment
-abc1
-abc2
-abc3
i want to store multiple values for single key(Name) within the array
While practicing java i have came across boolean data type. i have executed below program but i am not sure how i got output of the program like below:
10 > 9 is true
Here is my program:
class BoolTest3
{
public static void main(String args[])
{
System.out.println("10 > 9 is "+(10>9));
}
}
My question is: how this program will come to know that 10>9 true or false.. how bolean data type used in this program.
I'm writing a program that involves the use of set/get methods. I will submit a sample code of my issue. The format appears to be alright however the program is not returning any data. This is the same format as my actual code. Why this might be happening?
Java Code:
public static void main(String [] args) {
SecondClass object = new SecondClass();
object.setName("Name");
object.getName();
} mh_sh_highlight_all('java');
Java Code:
public class SecondClass {
private String name;
public SecondClass(){
name = " ";
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
} mh_sh_highlight_all('java');
i need to create an array with attributes name, gender, phone, age.and then sort acording to age in ascending order.
i created like this,
public class Array{
private String[] name={"ram", "katy", "priti", "john"};
private String[] gender={"male","female","female","male"};
private int[] phone={989898089,89898989,8982989089,898908989};
private int[] age={45,24,30,28};
public void printarray(){
[code]....
This code sorts the age attribute alone and when printing ouput it swaps one person's age to other person, how to make it correct
I am totally new to Java. What is the purpose of this method?
Flow of the int x=3; like where does the 3 go step by step?
Passing Primitive Data Type Arguments (from oracle java tutorials)
Primitive arguments, such as an int or a double, are passed into methods by value. This means that any changes to the values of the parameters exist only within the scope of the method. When the method returns, the parameters are gone and any changes to them are lost. Here is an example:
public class PassPrimitiveByValue {
public static void main(String[] args) {
int x = 3;
// invoke passMethod() with
// x as argument
passMethod(x);
[Code] ....
I was struggling to use BufferedReader to extract some data and then perform some calculations and then have the results as outputs.
I haven't quite solved that issue but in order to progress, I hard coded some values into my application and proceeded with the actual calculation loops etc.
Currently, the value out put from one of my calculations is given as:
1.1704926E7
How can I make the console show it in a natural way. I've performed the calculation manually and it should be 11704926.5 I don't want to lose that .5!
Primitive arguments, such as an int or a double, are passed into methods by value. This means that any changes to the values of the parameters exist only within the scope of the method. When the method returns, the parameters are gone and any changes to them are lost.
Reference data type parameters, such as objects, are also passed into methods by value. This means that when the method returns, the passed-in reference still references the same object as before. However, the values of the object's fields can be changed in the method, if they have the proper access level.For example, consider a method in an arbitrary class that moves Circle objects:
public void moveCircle(Circle circle, int deltaX, int deltaY) {
// code to move origin of
// circle to x+deltaX, y+deltaY
circle.setX(circle.getX() + deltaX);
circle.setY(circle.getY() + deltaY);
// code to assign a new
// reference to circle
circle = new Circle(0, 0);
}
Let the method be invoked with these arguments: moveCircle(myCircle, 23, 56)
Inside the method, circle initially refers to myCircle. The method changes the x and y coordinates of the object that circle references (i.e., myCircle) by 23 and 56, respectively. These changes will persist when the method returns. Then circle is assigned a reference to a new Circle object with x = y = 0. This reassignment has no permanence, however, because the reference was passed in by value and cannot change. Within the method, the object pointed to by circle has changed, but, when the method returns, myCircle still references the same Circle object as before the method was called.
I am trying to use double data type in a for loop for precise operations and just to see if there could be any problem doing that I tested a small code :
public class doubleLimit {
public static void main(String[] args){
for(double i=-0.1;i<=0;i+=0.01)
System.out.println(i); }}
The output I was expecting is :
-0.1
-0.09
-0.08
-0.07
-0.06
-0.05
-0.04
-0.03
-0.02
-0.01
0.00
But the output of the code is :
-0.1
-0.09000000000000001
-0.08000000000000002
-0.07000000000000002
-0.06000000000000002
-0.05000000000000002
-0.040000000000000015
-0.030000000000000013
-0.02000000000000001
-0.01000000000000001
-1.0408340855860843E-17
Why is the code not working the way I expected, I think it has something to do with any property of double but I am not sure.
Is this the proper way to add to a generic list? My code works just fine, but I got this feeling that there might be some kind of flaw in it or something. Is this pretty much the basic way to add any type of data to a generic list?
import java.util.LinkedList;
public class ListOfGeneric<E> {
private LinkedList<E> myList;
ListOfGeneric(){
myList = new LinkedList<E>();
[Code] ....
How do I pass the data within an initialized array from inside one method to another method of the same class? Will I need to return the array, assigning it to a temp array, which will then be passed as an argument to the other array? The idea is to create an array for an entire year, and be able to manipulate or edit data for a particular month using the other method.
public class Temperature {
static Scanner input = new Scanner(System.in);
static String [] monthArray = {"January", "February", "March", "April", "May",
"June", "July", "August", "October", "November", "December"};
public static void main(String[] args) {
[Code] .....
In my project i am facing an problem, The My SQL Data base will accept the date format of yyyy/mm/dd only as "Date" data type but in my program i wants to use dd/mm/yyyy format. (i have this same format now) that's why I am unable to insert / retrieve it..
View Replies View RelatedI have doubt in generics,
List<int> c=new ArrayList<int>();
why we cannot use primitive data type like int,double.