Changing Superclass Parameters?
Jul 16, 2014
My understanding was I could override a method from the superclass, including with different parameters, but when I try to use super. it gives me an error the arguments have to match the superclass. But, if I do that it won't make any sense.
The first code below is the superclass. The issue I'm having is on the second code at lines 7 and 10. The ultimate goal is to make a new class where I'm able to display various packages with or without insurance.
public class Package {
double shippingWeight;
public char shippingMethod;
final char air = 'A';
final char truck = 'T';
final char mail = 'M';
double shippingCost;
[code]....
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Apr 30, 2014
I have a question about query execution strategy ...
Scenario: let's suppose I've to query a table with a query like
SELECT F1, F2, F3 FROM MYTABLE WHERE F1 = ? AND F2 = ? AND F3 = ?.
I need to execute this query changing parameters' actual values in a combinatorial way, until a combination gives back at least one row or all combinations are unsuccessfully tried. For instance, I may have this sequence of values:
(V1,V2,V3);
(V1,V2,"");
(V1,"",V3);
(V1,"","");
where V1, V2, V3 may by string values and V1 is always present, not null, and not blank in each combination.
A first strategy may be to prepare the statement, clear the parameters each time I execute the query, until stop condition is met.
I wonder if may be more efficient transform the query into
SELECT F1, F2, F3 FROM MYTABLE WHERE F1 = V1
and cycling over the cursor and, for each cursor row, verify if the returned tuple (F1,F2,F3) matches the combination (V1x,V2x,V3x). When at least 1 rows matches, or all combination are done, I'll exit iteration.
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Jan 23, 2014
I've a question regarding polymorphism.
Is polymorphism possible only when the superclass is abstract?
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Mar 14, 2015
I am trying to display the getCommands() method from my subclasses but I do not know how to cast them both. At the moment I can only display one animals getCommands() method.
public class Test {
public static void main(String[] args) {
Pet [] pet = new Pet[5];
pet[0] = new Dog("Scamp", 1, "run");
pet[1] = new Dog("Molly", 2, "fetch");
pet[2] = new Dog("Rover", 3, "dig");
[Code] ....
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Apr 13, 2015
So far I thought that setting superclass member variables as protected would allow the subclasses to access them using this. and that this was a good approach. However now after further reading am finding that actually these variables are better set as private and then accessed by the subclasses using public method (getters and setters) or constructor.
So my question is do you recommend setting them as private instead of protected and what would be the best way to access these variables from the subclasses ?
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Oct 9, 2014
I would like to pass a variable I have in my main to my JFrame. In my main I calculate which pictures I should show in my JFrame. Is it possible to make objects of these pictures in my main class and use them in my JFrame? something like my code below.
public class JFrameTesting {
public static void main(String[] args) {
Image ImageVariable = Toolkit.getDefaultToolkit().getImage("C:1.jpg");
MyJFrame f = new MyJFrame();
f.setTitle("Drawing Graphics in Frames");
[code]....
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May 14, 2014
I'm using binding into fxml:
<Button fx:id="btnSalva" defaultButton="true" mnemonicParsing="false" disable="${controller.busy}"
onAction="#salva" prefHeight="57.0" prefWidth="141.0" styleClass="text-bold" text="Salva" />
Controller is my controller that extends another class from which it inherits busy property.
I see that fxmlloader only looks into the bottom class and not in superclasses, don't know if it's voluntarily or a bug.
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Apr 16, 2014
I have a superclass used for all the other entity
@MappedSuperclass
public abstract class BssStandardEntityLaravel extends BssStandardEntity
implements InterfacciaBssStandardEntity, Cloneable{
private static final long serialVersionUID = 1L;
@Column(name = "created_at", nullable=true)
@Temporal(TemporalType.TIMESTAMP)
protected Date created_at = new Date();
[Code] ....
When i try to read some data with a JPA controller, this error is raised:
Persistent class "com.bss.libbssabstract.database.entity.BssStandardEntityLaravel" has no table in the database, but the operation requires it. Please check the specification of the MetaData for this class.
org.datanucleus.store.rdbms.exceptions.NoTableManagedException: Persistent class "com.bss.libbssabstract.database.entity.BssStandardEntityLaravel" has no table in the database, but the operation requires it. Please check the specification of the MetaData for this class.
at org.datanucleus.store.rdbms.RDBMSStoreManager.getDatastoreClass(RDBMSStoreManager.java:702)
[Code] ....
It requires BssStandardEntityLaravel table like a normal entity. I used the same entity package in other applications and it works perfectly. Why this error is raised?
I use jpa2.1.0 and datanucleus to enhance classes
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Aug 25, 2014
i would like from my bean to redirect after an operation is completed to the page faces/test.xhtml?id=2? Is there a way to do this?
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Aug 2, 2014
So I created this line class and when I try to create Line object with parameters, I don't know how to pass the parameters properly. It has to return two points, so it should be like [(1,2),(5,12)].I tried different things likeLine l1=new Line(Point p1(1,2),Point p2(5,12)); and similar, but nothing worked.
package line;
import java.awt.Point;
public class Line {
private Point p1;
private Point p2;
[code]...
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Jan 31, 2015
public class TestClass {
public TestClass(String k){System.out.println(k);}
public static void main(String[] args) {
try {
hello();
}
catch(Exception e){System.out.println(e);}
[Code] ....
Explain how to catch block act as constructor with parameter?
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Mar 1, 2015
I have this JAVA written but I can't get the parameters for the if statements right.
import java.util.Scanner;
public class myFirstJAVA {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Please enter command: ");
String text = input.nextLine();
[Code] ....
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Sep 12, 2014
I'm trying to pass a parmeter to a jsf page from a servlet(i.e. associated with paypal adaptive api), but I keep getting the following error, even though the productType on ProductDetailsVO is a String.
INFO: WARNING: FacesMessage(s) have been enqueued, but may not have been displayed.
sourceId=j_idt2[severity=(ERROR 2), summary=(j_idt2: '45;productType=Sport'
must be a number consisting of one or more digits.), detail=(j_idt2: '45;productType=Sport' must be a number between -2147483648 and 2147483647 Example: 9346)]
Calling JSF page contains:-
returnURL = new URL(new URL(request.getRequestURL().toString()),"pages/paypalpaymentapproved.xhtml?paypalID="+paypalID+";productType=Sport");
response.sendRedirect(returnURL.toString());
[Code] ....
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Mar 19, 2014
How to use a constructor with parameters where the user inputs the information? I'm doing a problem where I create a Delivery class that accepts arguments for the year, delivery number within the year, distance code (1 for short distance, 2 for long), and weight of package. The constructor is supposed to also determine the eight digit delivery number (combining the year and delivery number, like 20140054 for this year, package #54).
I know I'm not close to being done but I'm struck on the application with the constructor parameters. If I'm asking the user to input the information, does that mean I have to create a no argument constructor so it will compile? Right now it won't compile because it's asking for the parameters but I can't put them.
This is the class:
public class Delivery {
int year;
int delNum;
double weight;
int code;
[Code] .....
And the error is:
CreateDelivery.java:22: error: constructor Delivery in class Delivery cannot be applied to given types;
Delivery firstDelivery = new Delivery();
^
required: int,int,int,double
found: no arguments
reason: actual and formal argument lists differ in length
1 error
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Feb 10, 2014
For example, if I have a class called Teacher with the constructor:
public Teacher(double yearsTeaching, boolean isMale, double age)
{
this.yearsTeaching = yearsTeaching;
this.isMale = isMale;
this.age = age;
}
How would I add it to these parameters to my ArrayList in my Tester class?
List<Teacher> teachers = new ArrayList<Teacher>();
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Feb 12, 2014
I have made a class here that has two methods. As you guys can notice, in my two methods that I made, I have listed some arguments in there with parameters. My question is that the variables im using in first method, can they be identical on my second method? Is this ok to do?
public class StudentScore {
private int math;
private int science;
private int calc;
private int history;
private int pe;
[Code] .....
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Jan 11, 2014
In the following Java Code:
public static void f() {
int n = 5;
p(n, 2 * n);
}
public static void p(int a, int b) {
int x = 1;
q(x, a + b);
}
public static void q(int x, int y) {
int z = x + y;
x = 0;
...
} mh_sh_highlight_all('java');
When we write x = 0; that refers to the formal parameter int x and hence it's the formal parameter that changes value. why isn't the value of the actual parameter also changing?
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Mar 7, 2015
Using Eclipse. I have this line of code:
BufferedReader br = new BufferedReader(new InputStreamReader(in));
I want to do something with br in a method that I defined. But Eclipse is complaining about br declared as
public static void Get_Next(String next_line, BufferedReader br) {
How do I make this work?
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May 26, 2014
So while experimenting with constructors, repeating constructors with the same parameters, and with different parameters. I got an output -explaining how I got it.
I made 2 classes. a "support class" (has all the info) and an "execute class" (executes info).
Support:
package inschool;
public class Constructors {
String video;
public Constructors() {
video = "frozen";
[Code] ....
Execute:
package inschool;
//this is part of Constructors class
public class App{
public static void main(String[] args){
[Code] ....
The Output:
the video name is frozen
Second constructor running
Constructor running!
the video name is frozen
Output Explanation:
constructor call number 1 and 3 are the same (essentially) and both refer to the same constructor.
My Question: if both call #1 and #3 refer to the same constructor, why is the output for #1 "the video name is frozen"
while the output for #3 used both methods in the accessed constructor-with the resulting output as
"Constructor running!"
and
"the video name is frozen"
I double checked the output-and this time made sure to scroll up ... its the same result
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May 31, 2014
I am trying to write a simple test case for one of my web service.The main method
return object :: offersService
MainClass
public OffersService getOffers(String input1, Map input2) {
// userId, Password loaded from another properties files
String response = validateUser(String userId, String Password)
[code]...
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Aug 7, 2014
If I have a method that takes an ArrayList of a class called Piece and it uses the setPosition() method from Piece. It is changing the value of the array that I passed in, but I want the ArrayList to stay the same outside of the method. Is there any way I can change only the values on the inside of the method, but keep the same position values outside the method?Here is an example.
Piece class
Java Code: public class Piece {
private int xCoor;
private int yCoor;
[code]....
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Mar 1, 2015
I want to have parameters that I use the "void" for, in other words it doesn't return anything.
class code
{
void go()
{
int TestStuff t = new TestStuff();
t.takeTwo(12,34)
}
void takeTwo (int x, int y) {
int z = x + y;
System.out.println("Total is:" + z);
}
}
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Sep 25, 2014
I am currently working on Java software which resize jpeg images and change DPI also. For JPEG images having app0JFIF node it works fine and the images new DPI is reflected in Photoshop. But if app0JFIF node not exist, I am trying to create a new one and set the DPI value there. Everything is going proper but if I open these images in photoshop it does not reflect new DPI but the size changes.
Java Code:
double dpi_in_inch = 0.393701 * newres;
File file1 = new File(imgName);
image = ImageIO.read(file1);
int wd, hi;
wd = (int) (newsize * dpi_in_inch);
[Code] ...
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Sep 16, 2014
I'm using JSF framework. I can let Netbeans to create the persistence unit and hardcodes connection parameters into the persistence.xml file or i can use resource tag in context.xml file or using another file like property file or class for holding connection parameters like username and password; what is the most secure way or expert way to use connection properties in my app or there is no difference?
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Jul 30, 2006
What is the difference between Attributes and Parameters.that is difference between two methods request.getAttribute() and request.getParameter() and why we have this two methods?
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Aug 6, 2008
I am using AXIS2 tomcat6 and jre1.6.0_07 and I created java project using net beans. but when I execute java2wsdl I am getting the following. Can you solve my problem? Also I would like to know what is the function of java2wsdl and its parameters?T
C:axis2-1.4-binaxis2-1.4in>%AXIS2_HOME%injava2wsdl -cp . -cn samples.quickstart.service.pojo.StockQuoteService -of StockQuoteService.wsdlUsing AXIS2_HOME: c:axis2-1.4-binaxis2-1.4Using JAVA_HOME: C:Program FilesJavajre1.6.0_07An error occured while generating codejava.lang.ClassNotFoundException: samples.quickstart.service.pojo.StockQuoteService C:axis2-1.4-binaxis2-1.4in>
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