Comparing Two Different Object Types With Common Attributes
Aug 18, 2014
I have two different "business objects", and they have multiple attributes in common(around 25 I believe, all of which are simply a String). Basically, these objects are used for documentation purposes on the same file.
The program can choose to update a given Document at any point in time, even if changes haven't been made to existing version. So what I'm trying to do, is check to see if these attributes differ any between the two files(the exisitng copy, and the new request). If so, I'll update...else I simply throw out the request. The workload can be rather intense at times so I don't want to bog down the system anymore then necessary.
Simply pulling down every attribute for each and comparing seems like a lot of overhead, any more efficient way to achieve these results?
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Oct 15, 2014
import java.util.*;
public class CommonElements
{
private int comparisons; // number of comparisons made
private Comparable[] arrayToSearch; // current array being traversed
private Comparable[] commonElements = new Comparable[10];
private int arrayPosition = 0; //keeps track of what index to add an element to common at
[Code] ...
I have trying to get this down to the bar minimum. I am trying to cast the desired object array to a array of comparable. This is all required by the assignment.
I am getting a runtime error that I can not perform the desired cast. What do I need to provide the compiler in order to allow for this casting. I can not change the signature of the method however nothing about the class has been specified do I need to implement comparable? Also I don not now what the client is passing so how would I write a generic compareTo method to compare object of unknown types.
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Oct 7, 2014
I am new to Java and have read books, the Java docs, and searched the Internet for my problem to no avail. I have an Array of objects that contains strings. How can I get the object's strings to print in a list so that the user can select that object to manipulate its attributes? For example, the user can select "Guitar 1" from a list and manipulate its attributes like tuning it, playing it, etc. I have a class called Instruments and created 10 guitar objects.Here is the code:
Instrument [] guitar = new Instrument[10];
for (int i = 0; i < 10; i++) {
guitar[0] = new Instrument("Guitar 1");
guitar[1] = new Instrument("Guitar 2");
guitar[2] = new Instrument("Guitar 3");
guitar[3] = new Instrument("Guitar 4");
guitar[4] = new Instrument("Guitar 5");
guitar[5] = new Instrument("Guitar 6");
[code]...
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Feb 5, 2015
when a new object is created in Java it follows the idiom:
Object obj = new Object();
where the Object() constructor matches the object type Object.
But what if it doesn't? I understand from the Oracle Docs on creating objects and polymorphism that the constructor must be in that object's class or one of its subclasses. However, suppose we wanted to declare a new stack. My first instinct would be:
Stack s1 = new Stack();
But I assume it's valid to do it this way, too:
Object s2 = new Stack(); // Is there a difference here? What are we really saying about s2? I'm guessing s2 is simply an empty stack, but only has access to the Object class methods? I'm not sure why someone would ever do this, but I want to solidify my understanding of the Java hierarchy. Are there really any circumstances where someone would use a subclass's constructor when creating a new object?
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Jan 29, 2014
"What happens if you modify the common object references in these lists, myArrList and urArrList ? We have 2 cases here: In the first one, you reassign the object reference using either of the lists. In this case, the value in the second list will remain unchanged.In the second case, you modify the internals of any of the common list elements - in this case, the change will be reflected in both lists."
I have written the following code, which tests the first case mentioned above, and i get the output as expected: myarrList remains unchanged. How can i test the second case ? My thoughts are ....'second case is untestable the following code, because String is immutable. I need to use StringBuilder or something else to write code for test of second case mentioned'.
ArrayList<String> myarrList = new ArrayList<>();
myarrList.add("one");
myarrList.add("two");
ArrayList<String> urarrList = new ArrayList<>();
urarrList.add("three");
urarrList.add("four");
System.out.println("ArrayLists setup");
[code]....
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Dec 29, 2014
public class BookExamples {
String title;
String genre;
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("Hey");
[code]...
Eclipse gives me an error for b1.genre = "hey"; saying "Syntax error on token "genre", VariableDeclaratorId expected after this token". I am learning from a HeadFirst Java book that is all in Java 5.0 version which may be part of the problem.
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Oct 6, 2014
I have an Array of objects that contains strings. I am new to Java and have read books, the Java docs, and searched the Internet for my problem to no avail. How can I get my strings to print in a list so that the user can select an object to manipulate its attributes? I have a class called Instruments and created 10 guitar objects. Here is the code:
Instrument [] guitar = new Instrument[10];
for (int i = 0; i < 10; i++) {
guitar[0] = new Instrument("Guitar 1");
guitar[1] = new Instrument("Guitar 2");
guitar[2] = new Instrument("Guitar 3");
guitar[3] = new Instrument("Guitar 4");
[Code] ....
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Mar 17, 2014
how objects relate to classes and how you can create and re-use object types.on that point, but this has me baffled. I most certainly do not have a firm grasp yet on passing things to and from methods that just makes my head hurt. SO anyway I tried out one of the code examples:
/* ElectricGuitar.java */
class ElectricGuitar {
String brand;
int numOfPickups;
boolean rockStarUsesIt;
[code]...
But I just realized this thing has no main method and only one class defined.....so I guess I just tried to compile.
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Dec 8, 2014
I need to write a class that represents and image of RGB pixels. This class uses a two-dimensional array of object type that represents R,G and B values.
When I compile the class it completes successfully. However, when I try running a "tester" class , I'm encountering errors in a few methods. I've been trying it out for 2 days now, but unsuccessfully thus far..Those method are : rotating the image by 90 degrees clockwise (and vice versa , but I just use clockwise method 3 times for that) , shifting the image sideways, and shifting the image up/down..
I've attached the whole source code for the class , and the list of errors I get when I try to run my tester. URL...
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Jul 1, 2014
Here's My Code.
package bin;
import java.util.Scanner;
public class AppletMain{
public static void main(String[] args){
Scanner oneinput = new Scanner(System.in);
String one;
[Code] ....
I am trying to get it to compare the word I type in to the set word in the object 'secretword'. I have tried everything from equal to == to compareTo, I even created a two hundred line program to do this SIMPLE problem.
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Jun 29, 2014
How to use common functions and constants in one jsp page which are used in another jsp page on page load time?
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May 12, 2014
Which of these is not a real differentiator for programming languages:
a) Object-oriented / Process-Oriented
b) Interactive / Automated
c) Interpreted / Compiled
d) Strongly-Typed / Weakly-Typed
e) All of the above
f) B and C
g) B and D
Almost all support OOP, Interactive/Automated, Interpreted/Compiled but not sure about Strongly typed/Weakly typed.
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Apr 6, 2015
I have two ArrayLists and I want to compare them for common elements, and based on the result I want to update the first Arraylist to only have these elements. sort of like the opposite of RemoveAll() which removes elements in common and keep the ones that are unique. so far I thought of using for loop and .contains() in case it was fault,element not present, remove from list. but I was wondering
in what other ways, perhaps APIs i can use to do that?
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Mar 19, 2014
I need to create an algorithm that finds the common element(s) in all arrays that has a signature of public Comparable[] findCommonElements(Object[] collection) that has an efficiency of at most O(knlogn), uses a query array, and accepts as input a collection of arrays. I am aware my time would be better spent learning how to use array lists and hash sets, but I am supposed to use concepts already covered, and these have not been.
I feel like this code should work, but it is returning null for the array of common elements. Which means it obviously is not working correctly. I am also likely going to need implementing the sort algorithm, but I wanted to get the part of finding the common elements set first.
public class CommonElements2<T extends Comparable<T>>
{
Comparable[] tempArr;
Comparable[] common;
Comparable[] queryArray;
/*
sort algorithm goes here
*/
public Comparable[] findCommonElements(Object[] collections)
[code]....
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Mar 16, 2015
I have developed a web portal using jsp and struts 2. I have approximately 10 JSP pages which looks exactly the same and have two text areas and two hidden fields. All 10 pages are exactly the same except for hidden field value. Can't i have a single common jsp page. How can i achieve it. A sample page i am attaching...
<%@ page contentType="text/html; charset=UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<%@ page pageEncoding="UTF-8"%>
<%@ page language="java"%>
[Code]....
As this is an Assignment page so hidden field value is assignment. If the page is OBJECTIVEs then value will be OBJECTIVE.
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Sep 17, 2014
i need to find common String between to Strings :
Example 1:
Customer Name 1: Dr. Joe Smith
Customer Name 2: Joseph Smith, MD.
I need to search the string for a match, in this example "Smith"
Example 2:
Customer Name1: New York Market Place
Customer Name 2: NY Marketplace
I need to search the string for a match, in this example Market place
Example 3:
Customer Name1: The Deli on the Corner
Customer Name 2: Corner Deli
I need to search the string for a match, in this example Deli Corner
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May 14, 2015
I am using the following regex - [a-zA-Z0-9]{9,18} which means I can use alphabets and numbers with minimum length as 9 and maximum length as 18.It should not take special characters.
It takes values like ADV0098890 etc. but it is also taking ADV0098890[] which is wrong.
How can I prevent that ?
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Oct 16, 2014
After learning about Euclid's Algorithm for finding the greatest common divisor of 2 integers, I decided to make a demo program in Java.
public static int gcd(int number1, int number2) {
int num1 = number1;
int num2 = number2;
if(number1 < number2){
[Code] .....
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Feb 7, 2007
import javax.swing.*;
public class mostFrequent{
public static void main(String args[]){
char index;
String s;
s = JOptionPane.showInputDialog("Enter String here");
int currFrequency = 0;
for(index = 0; index<s.length(); index = index++){
int i = 0;
for(i = 'A'; i<='Z'; i++){
if(i==s.charAt(index)){
currFrequency = currFrequency + 1;
}
}
}
System.out.println("end");
}
}
//my code so far
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Jul 16, 2013
I have a small problem to solve by which I would like to merge 2 sorted maps into 1.
Map A
-------
Keys, Values
1, A
2, B
3, C
4, D
5, E
Map B
-------
Keys, Values
1, 10
2, 20
3, 30
4, 40
5, 50
Final Map should look like:
Keys, Values
A, 10
B, 20
C, 30
D, 40
E, 50
The final map would have all the values from Map A as a key and the values from Map B as values in the Final Map. Is there a way to do this using Java?
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Jan 31, 2015
I have done one program, that calculates the Least Common Multiple. The idea is to use WindowsBuilder on Ecplise in order to run it in a separate window. But when I started nothing happens. The code is:
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.unit.Scanner;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
[Code] ....
Just wondering what could I do to make it happen. One thing came up on my mind - this is that need to connect the button with the function of the method, but still not sure will work.
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Aug 26, 2014
I am working with Netbeans 8.0 and JSF2.2. I am trying to create a web site that has a common header, footer, and menu. The only part that would be dynamic is the content. So here goes...
1) I need a common template that has 4 parts, Header, Footer, Menu, Content
2) The header, footer and menu are to be in a separate files of which are called from the main template
3) The content will change based on the menu item changed
4) The menu has to change the content section only
I know how to do this in HTML but I am trying to set up some thing in JSF to learn more on JSF pages. All I am looking for is an example that I can follow along with having the multiple pages as well having the menu change the content (I have done a ton of internet searching but nothing really fits the bill).
This is the code I have currently.
Index (Main Template)
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://xmlns.jcp.org/jsf/facelets"
xmlns:h="http://xmlns.jcp.org/jsf/html">
[Code] .....
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Sep 25, 2014
In attempting to find the greatest common divisor (gcd) of two integers, n1 and n2, whereas k is a possible gcd and gcd is initialized to 1, the following code has been entered:
for (int k = 2; k <= n1 && k <= n2; k++) {
if ( n1 % 2 == 0 && n2 % 2 == 0)
gcd= k;
}
When asked to change the previous line of code to this:
for (int k = 2; k <= n1 / 2 && k < n2 / 2; k++){
the questions states this revision is wrong and to find the reason.....well, I've changed it, entered "3" (per the answer key) for n1 and n2....
now I can see logically where k (2 in this example) is not <= n1/2, which is 3/2 or 1, since we're dealing w/integers, yet when I compile and run, my answer is indeed, gcd = 1. However, since this is a Boolean expression where && is being used, since the first portion evaluates to "false", the 2nd portion isn't executed and thus my result of 1?...... loops are throwing me for one, for sure....
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Dec 17, 2014
My program is user input 20 char and the program will print the most common. So I use another int arr which count the number appears in the original array. i know its not so Effective but I don't know why it run but it stop in the middle. I got this code :
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 20
at Ex2.common(Ex2.java:39)
at Ex2.main(Ex2.java:23)
import java.util.Scanner;
class Ex2 {
public static void main(String[] arg) {
Scanner reader = new Scanner (System.in);
char[] arr=new char[20];
System.out.println("Please enter 20 chars:");
for (int i=0;i<20;i++)
[Code] ....
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Jan 21, 2014
I would like to use the attribute A of my class Selecter1, in my main class Resizing. How?
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Mar 19, 2014
We can have attributes in different scopes in a JSP page. Suppose there is an attribute named 'name' with values in different scopes as below:
request - A
session - B
application - C
page - D
Suppose I print ${name} in a JSP page, then what will be the value printed on the JSP? And, what will be the preference order of attributes search in different scopes?
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