Guideline for deciding method return type
Hi All,
I have some concerns in deciding the return type of some specific methods in the application (web service application to be specific).
Concern: There are methods like 'deleteData', 'cancelProcess', 'uploadData' etc. Ideally these methods don't require server to perform complex business logic. Now there are 2 views to decide the return type of these methods. The first approach could be to return a boolean indicating whether the operation is successful or not and the other apporach is to return void but throw an exception if anything goes wrong.
Both approaches have their own advantages and drawbacks. Sending a boolean seems to be cleaner but in case of unsuccess caller won't get the exact exception but just a flag. In second apporach, the caller has to rely on try/catch to decide the logical flow.
I know, there can't be any generic answer to this question but I just wanted to know comments from experts on this or probably some guidelines.
Thanks and Regards,
Ashish Arya
If there is a legitimate reason why your method might not actually do what it should, then use the boolean return value.
Example: someList.remove("foo") will return false if "foo" is not actually in the list (because remove() simply specifies that it will make sure that the element is not in the list after the call. Since this is fulfilled in this case, there's no case to throw an exception, even if it didn't actually remove anything).
If the only reason for not doing what it should is some error condition, then throw an exception:
Example: someList.get(100) will throw an exception, when the list has less than 101 elements.
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The class of the deferred-methods return type "{0}" can not be found.
I am developing a multilingual portal application.
I have the method that changes the locale based on user's choice in the bean and the method is being referred to as below.
<af:selectOneChoice label="Select Language" autoSubmit="true"
value="#{localeBean.locale}"
valueChangeListener="localeBean.changeLocale">
<af:selectItem label="English" value="en" id="si1"/>
<af:selectItem label="French" value="fr" id="si2"/>
<af:selectItem label="Dutch" value="nl" id="si3"/>
</af:selectOneChoice>
when i try to run the application, i am getting compile time errors as below,
The class of the deferred-methods return type "{0}" can not be found.
No property editor found for the bean "javax.el.MethodExpression".
After going through the discussion forums i learned that the compilation errors can be resolved by setting the <jsp:directive.page deferredSyntaxAllowedAsLiteral="false> at the starting of the page.
Even after that i am getting the compilation error.
Any solutions, suggestions or possible approaches would be helpful as i am new to Webcenter Portal development.
Thanks,The error you get points to a problem on the page (somewhere). Switch to source mode and check the right margin if you see orange or red marks. These are pointing to problems (not all are show stoppers, but they give you hints that something is not according to the standard for jsf, jsff, jsp or jspx pages.
Have you checked that the bean is correctly defined and that it's reachable?
Start a fresh page and isolate the problem, e.g. build a selectOneChoiuce on the new page (don't copy it as you might copy the error too) and make it work on the new page. Once you have it running you can compare the solution to your not running page.
Timo -
OracleDbType for function OBJECT return type
Hi all,
I inherited an oracle function that has an object as a return type:
create or replace TYPE OBJECTPATH IS OBJECT (OBJECTID NUMBER);
create or replace TYPE OBJECTPATH_TAB AS TABLE OF OBJECTPATH;
create or replace FUNCTION GETOBJECTINPATH ( pobjectid in NUMBER, role1 varchar2, role2 varchar2 ) RETURN OBJECTPATH_TAB
IS
v_tmp_tab OBJECTPATH_TAB:=OBJECTPATH_TAB();
parentid NUMBER;
rowno INTEGER;
BEGIN
rowno:=0;
parentid:=pobjectid;
loop
select objectid into parentid from dual left join (select ro2.objectid from relationshipobject ro1, relationshipobject ro2
where ro1.role=role1 and ro2.role=role2 and ro1.relationshipid=ro2.relationshipid and ro1.objectid=parentid)
on 1=1;
if parentid is null then
exit;
end if;
v_tmp_tab.extend;
rowno:=rowno1;+
v_tmp_tab(rowno) := OBJECTPATH(parentid);
end loop;
RETURN v_tmp_tab;
END;
On my application side, I am trying to run this function and retrieve the return value with ODP.NET as below. However, I am stumped when I need to supply an OracleDbType for the function return type.
1. What is the OracleDbType I should use for the return type? I read that there used to be support for OracleDbType.Object, but it seems like it is now not supported. I am using ODP.NET 11g. Am I getting the situation correct?
2. If retrieving an object return type is not as straightforward as setting the parameters (as what I have done below), what is the workaround to achieve it?
OracleCommand runGetPObjectInPathCmd = new OracleCommand("GETOBJECTINPATH", conn);
runGetPObjectInPathCmd.CommandType = CommandType.StoredProcedure;
runGetPObjectInPathCmd.Parameters.Add(new OracleParameter("pobjectid", OracleDbType.Decimal)).Value = pobjectId;
runGetPObjectInPathCmd.Parameters["pobjectid"].Direction = ParameterDirection.Input;
runGetPObjectInPathCmd.Parameters.Add(new OracleParameter("role1", OracleDbType.Varchar2, 255)).Value = role1;
runGetPObjectInPathCmd.Parameters["role1"].Direction = ParameterDirection.Input;
runGetPObjectInPathCmd.Parameters.Add(new OracleParameter("role2", OracleDbType.Varchar2, 255)).Value = role2;
runGetPObjectInPathCmd.Parameters["role2"].Direction = ParameterDirection.Input;
runGetPObjectInPathCmd.Parameters.Add("OBJECTPATH_TAB", OracleDbType.Decimal); // this is not correct as the return type is not a NUMBER
runGetPObjectInPathCmd.Parameters["OBJECTPATH_TAB"].Direction = ParameterDirection.ReturnValue;
runGetPObjectInPathCmd.ExecuteNonQuery();
Thanks in advance for any help and would greatly appreciate it.Hi Greg,
Thanks for your reply. I am not exactly sure whether I am using 11.1.0.6.21. The Oracle.DataAccess.dll I see under my \ODP.NET\bin\2.x directory is of Assembly/Product Version 2.111.6.0 - is this version 11.1.0.6.21? I also do not have the samples directory. Am I working on a wrong version? Thanks for your patience as I am really new to this and appreciate your guidance. -
Guidelines for deciding directory structure for Swing Application
Hi,
We are developing a Swing Application for our organization. We want to organize the code and resources/icons/properties files in correct manner.
We have guidelines for arranging the code for web application. Is there any such guidelines available for desktop application as well? What is the preferred location for keeping the icons and properties files?
Regards,
ManuThanks Maran.
I have already checked many installation guides before posting here. All of them mention about creating folders like /admin or /oradata on various mount points but none of the naming conventions really indicate whether it is a 8i database or a 10g database.
This is required when you are having multiple Oracle installations under /opt and databases are running from different mount points.
Regards, -
EJB3 Creating Web Services with Complex Return Types
Hi
Not sure if this is the right place, but hoping someone can help!
I have an entity bean that has a collection (list<Address>) of sub-entities. I have then created a session bean to retrieve the Business and populate it's children.
I then expose this as a web service and although it works and I get appropriate XML out, the WSDL of the deployed service is not as I would like.
For example:
The return type is
<complextype name="Business">
<sequence>
<element name="id" type="int"/>
<element name="addresses" type="ns1:list"/>
</sequence>
</complextype>
<complextype name="Address">
<sequence>
<element name="id" type="int"/>
<element name="addresses1" type="string"/>
<element name="addresses2" type="string"/>
<element name="addresses3" type="string"/>
</sequence>
</complextype>
ns1:list is included as a separate schema as a complex extension of the base "collection"
So, even though the Address type is there it is not referenced from Business.
So, when I'm calling the Web Service from BPEL or ESB, I have not got the ability to map adequately back from the response.
I have tried a whole bunch of ways of getting this to work, but so far to no avail...
Has anyone seen this before, or can I somehow override the mapping from the Entity to the WSDL?
Any help would be most appreciated.
Thanks
ChrisThanks. We are using a Java Proxy to consume the web service as we need to use JAX-WS handlers. We created data control from the service stub that was created by the proxy. Our issue is with the response XML which comes as a complex type. Also, the data control is understanding the complex type and is creating the structure right. The problem is when we drag that control on a JSF page. No data is displayed. We think that we are not traversing the complex object properly which is creating the issue.
I understand that you answer related to the input is applicable to output as well. We can change the structure by flattening it but we thought that in 11G there is some new features where we can use the complex types out of the box without any change. Is that true? Also, any luck in finding the documents (broken links) on your blog page? -
Best way to handle Interface Return Type for Web Service Method
Hi All,
i have the followinig situation. I would like to create a method as a web service:
Customer getCustomer(someType){....}
ie: getCustomer method, with a parameter that indicates some backend data source. The method returns a Customer object. However, depending on the datasource this method uses (which is dependent on the type passed in, ie FooDB, BarDB etc) then i return either a:
FooCustomer extends AbstractCustomer implements Customer
BarCustomer extends AbstractCustomer implements Customer
Now this fails because JAXB cant handle interfaces because when sending XML over the wire it needs a concrete representation (as far as i understand).
So how should i deal with this?
Do I need to create a differnet method for each datasource (foo DB, bar DB), ie:
FooCustomer getFooCustomer()
BarCustomer getBarCustomer()
or do i continue calling getCustomer but somehow indicate in the WSDL that I have an AbstractCustomer object and some other bits from FooCusotmer or BarCustomer or ....
kinda stumpeed here? I wouldve thought itd be handy to be able to do this (ie: call one getCustomer() method and get back Customer objects representing nay type of customer ... in some way...but cant see how to achieve this.
Any pointers would be greatly appreciated
cheers
MartyTry to explore abstract schema type.
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Hello,
My entity manager executes a native query for a count(*) operation to get the row count from a table. But I am confused to see that while executing I get different datatypes such BigInteger, BigDecimal etc on different runs of the same query. Why is this so?
What is the deciding factor for count queries data type??
Please help....The whole point of a constructor is to create an object on the heap and return a reference to that memory block. In fact the call to the constructor will return a reference to the instantiated object. Thus there is no point in specifying a return type to a constructor.
If you think about the way we call the constructor then it's obvious that it's not a regular method which goes inside an object.
Hope this will do what you want :) -
Non-void return type for Application Module Clients Interface
Hello, can anyone guide me on how will I solve my problem.
first of all, I'm using JDeveloper 10.1.3, I use JSF, ADF Faces, ADF Model, ADF Business Components.
I made a web page that has a Transactional Capabilities, all is going smoothly, all data's can be saved to oracle database. I created a Custom Method in my Application Module and can be used in Clients Interface, that method is for saving data's to database.
My problem is I dont know how to create a custom method that returns a value in my Application Module. Which means if I set it to non-void return type, it is not visible to Client Interface. If you're going to ask me why I need it to return a value? Well since that method is for saving data's, if there's an Error Occured, I can return the Error Message and show it to my user interface.
Please help. thanksIf you want to return your own type then simply define it as serializable and you will find that it will appear in the Client Interface dialog of your AM.
eg, you could return this type from your application module to progagate a meaningful message to your UI:
package com.delexian.model;
import java.io.Serializable;
public class MyMessage implements Serializable {
private String _severity;
private String _message;
public MyMessage() {
public void setSeverity(String severity) {
this._severity = severity;
public String getSeverity() {
return _severity;
public void setMessage(String message) {
this._message = message;
public String getMessage() {
return _message;
}regards,
Brenden -
Is there a way to end a method that has no return type?
Without using an exception, as they are costly I am told, and without using may if then statements, is it possible to end a method if some criteria isn't met.
example.
public void doThis(){
// the method relies on the state of some
// other things.
if(!someBoolean) endHere
// then following is the rest of the method.
// I'd like to be able to do this so that the "meat"
// of the method is located under the conditions
// that must be met.
}... Any thoughts?
Thank YouNo need to hide or commit ritual suicide, the "void" keyword could lead you to think that your method can't use the return statement. At least you wrote code to investigate and didn't spend 10 or 20 posts asking for verification. Be aware, some folk will tell you that there should be only one exit point from the method, often this is true. In large methods you can get lost in the execution path if there are multiple exit points. I think it's a judgement call.
As for returning a bogus boolean, but, from a design point of view, if your method really doesn't have anything to return to its caller then the signature should reflect that with a return type of void (I know you are suggesting returning the bogus boolean for a different reason, and you've abandoned the idea anyway, I'm just being pedantic here)(indulge me). Returning a bogus boolean makes the class method more difficult to understand from a design and JavaDoc point of view because I, as the user of your method, will see it returing a boolean and expect to be able to use that value, and it might color my view of what the method does.
Lee -
Getting an Annotation for a Return Type (Java 1.5 Beta)
Hi
I am trying to access the annoation information on a class using reflection. I can't find any way to get access to an annotation on the return type of a method. For example the code below complies however there is no method on the "java.lang.reflect.Method" class (that I can see) that gives me access to the annoation.
Could someone point me to something I may have misses.
example:
import java.lang.annotation.*;
@Retention(value=RetentionPolicy.RUNTIME)
@Target(value=ElementType.ANNOTATION_TYPE)
public @interface MyAnnotation {
String value();
public class TestClass {
public static @MyAnnotation("hello")void myMethod() {
Thank
Raymond McCraeThe annotation isn't on the return type, it is on the method.
You want the method
public <T extends Annotation> T getAnnotation(Class<T> annotationClass);It is used like this
MyAnnotation m = TestClass.getMethod("myMethod").getAnnotation(MyAnnotation.class);Note that it is typesafe! -
Asking for return type with constructor
import java.swing.*;
public class firstWindow extends JFrame
public static final int WIDTH = 300;
public static final int HEIGHT = 200;
public FirstWindow()
super();
setSize(WIDTH,HEIGHT);
JLabel newLabel = new JLabel("My Medical Record.");
getContentPane().add(newLabel);
WindowDestroyer listener = new WindowDestroyer();
addWindowListener(listener);
}Continue to get a 'method with no return type'. I looked for a syntax error but can't see it.
Edited by: Zarnon on Mar 2, 2008 2:07 PMradiorx wrote:
public FirstWindow()Class name is firstWindow, so the constructor should be re-named :
public firstWindow()In the former case, the FirstWindow identifier creates a method rather than a constructor, and methods in Java need a return type.
Hope this helpsInstead of renaming the constructor, rename the class file public class firstWindow extends JFrame into public class FirstWindow extends JFrame -
Implementing Empty Versions of Interface Methods with Return Types
Subject probably is probably a bit long but I was stumped for a brief way to summarize my question. Let's say I have the interface below:
public interface DAO {
...snip...
public Object get(int id);
public Object[] get(String clause);
...snip...
}From this I want to make two concrete classes, say ClassOne and ClassTwo. Given the type of data each one is fetching, ClassOne only needs (and should only) implement get(int id) and ClassTwo only needs (and should only) implement get(String clause). This is because the first class will always deal with only one record from table_a and the second class will always deal with one or more records from table_b. So my question is what is the correct way to provide empty implementations for the unnecessary methods?
I've thought of using an adapter to implement empty methods but a) I'm not sure that makes sense and b) I still end up have to return something. Another option was maybe having multiple interfaces, one returning a single object and the other returning an array. Neither of those options felt right and looked a bit goofy when I prototyped them out. It seems to me that I wouldn't want the classes using the concrete DAO classes to be able to call the wrong method, but I don't know how to hide the unused method. Right now I just return an empty Object or Object[] for the unused method but that seems goofy too, and makes the class using ClassOne or ClassTwo know the innards of the implementations.
Anyway, any tips appreciated.
Thanks,
PabloIt sounds as if the methods weren't meant to be together, and so I'm wondering if you aren't better off with two distinct interfaces, one for each method. Otherwise one solution would be to implement a method that throws an exception if it is not meant to be called.
edit: D'oh! Just when you least expect them, Ninjas! They're everywhere!
Edited by: Encephalopathic on Apr 30, 2009 1:41 PM -
Invalid method declaration; return type required
The code:
public Reminder(int seconds) {
timer = new Timer();
timer.schedule(new RemindTask(), seconds*1000);
class RemindTask extends TimerTask {
public void run() {
System.out.format("Time's up!%n");
timer.cancel(); //Terminate the timer thread
public static void main(String[] args)
JFrame.setDefaultLookAndFeelDecorated(true);
JDialog.setDefaultLookAndFeelDecorated(true);
try
UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
catch (Exception ex)
System.out.println("Failed loading L&F: ");
System.out.println(ex);
new superball();
new Reminder(5);
System.out.format("Task scheduled.%n");
//= End of Testing =
}Gives:
"invalid method declaration; return type required"
If i add void to public Reminder(int seconds) {It prints:
cannot find symbol
symbol : class Reminder
location: class superball
new Reminder(5);
Is it because of the public class?
public class superball extends JFrameHere is the FULL code:
/* superball */
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.regex.Pattern;
import java.util.Timer;
import java.util.TimerTask;
import java.util.*;
import java.io.*;
* Summary description for superball
public class superball extends JFrame
// Variables declaration
int ballx;
int bally;
int jumpstop;
int stopper;
int coin;
int coinx;
int coiny;
int coinvaluex;
int coinvaluey;
Timer timer;
private int value = 0;
private static Random r = new Random();
private JLabel jLabel1;
private JLabel jLabel2;
private JLabel jLabel4;
private JLabel jLabel5;
private JLabel jLabel7;
private JLabel jLabel9;
private JLabel jLabel10;
private JPanel contentPane;
private JPanel jPanel1;
// End of variables declaration
public superball()
super();
initializeComponent();
// TODO: Add any constructor code after initializeComponent call
this.setVisible(true);
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always regenerated
* by the Windows Form Designer. Otherwise, retrieving design might not work properly.
* Tip: If you must revise this method, please backup this GUI file for JFrameBuilder
* to retrieve your design properly in future, before revising this method.
private void initializeComponent()
jLabel1 = new JLabel();
jLabel2 = new JLabel();
jLabel4 = new JLabel();
jLabel5 = new JLabel();
jLabel7 = new JLabel();
jLabel9 = new JLabel();
jLabel10 = new JLabel();
coin = 1;
coinx = Math.abs(r.nextInt()) % 460 + 100;
coiny = Math.abs(r.nextInt()) % 200 + 100;
ballx = 342;
bally = 338;
jumpstop = 0;
stopper = 13;
contentPane = (JPanel)this.getContentPane();
jPanel1 = new JPanel();
// jLabel1
jLabel1.setIcon(new ImageIcon("IMG\\coin.gif"));
jLabel1.setText("0");
// jLabel2
jLabel2.setIcon(new ImageIcon("IMG\\logo.PNG"));
// jLabel4
jLabel4.setIcon(new ImageIcon("IMG\\black.GIF"));
// jLabel5
jLabel5.setIcon(new ImageIcon("IMG\\ballstanding2.gif"));
// jLabel7
jLabel7.setIcon(new ImageIcon("IMG\\star-heart.gif"));
jLabel7.setText(" 100");
// jLabel9
jLabel9.setIcon(new ImageIcon("IMG\\coin.gif"));
// jLabel10
jLabel10.setIcon(new ImageIcon("IMG\\stage1.GIF"));
// contentPane
contentPane.setLayout(null);
contentPane.setBackground(new Color(255, 254, 254));
addComponent(contentPane, jLabel5, 342,338,60,18);
addComponent(contentPane, jLabel1, 561,4,100,18);
addComponent(contentPane, jLabel2, 2,3,208,24);
addComponent(contentPane, jLabel7, 495,4,60,18);
addComponent(contentPane, jLabel9, coinx,coiny,19,18);
addComponent(contentPane, jLabel2, 2,3,208,24);
addComponent(contentPane, jLabel10, -2,29,738,412);
addComponent(contentPane, jPanel1, 79,209,200,100);
// jPanel1
jPanel1.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));
jPanel1.setFocusable(true);
jPanel1.addKeyListener(new KeyAdapter() {
public void keyPressed(KeyEvent e)
jPanel1_keyPressed(e);
public void keyReleased(KeyEvent e)
jPanel1_keyReleased(e);
public void keyTyped(KeyEvent e)
jPanel1_keyTyped(e);
// superball
this.setTitle("Superball created by Hannes Karlsson");
this.setLocation(new Point(0, 0));
this.setSize(new Dimension(617, 450));
this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
this.setResizable(false);
/** Add Component Without a Layout Manager (Absolute Positioning) */
private void addComponent(Container container,Component c,int x,int y,int width,int height)
c.setBounds(x,y,width,height);
container.add(c);
// TODO: Add any appropriate code in the following Event Handling Methods
private void jPanel1_keyPressed(KeyEvent e)
System.out.println("\njPanel1_keyPressed(KeyEvent e) called.");
// TODO: Add any handling code here
if(e.getKeyCode()==e.VK_LEFT) // when the user enters left
jLabel5.setLocation(new Point(ballx--, bally));
jLabel5.setLocation(new Point(ballx--, bally));
jLabel5.setLocation(new Point(ballx--, bally));
jLabel5.setLocation(new Point(ballx--, bally));
jLabel5.setIcon(new ImageIcon("IMG\\ballroll.gif"));
} // equalling PLAIN_SPEED
if(e.getKeyCode()==e.VK_RIGHT) // when the user enters right
jLabel5.setLocation(new Point(ballx++, bally));
jLabel5.setLocation(new Point(ballx++, bally));
jLabel5.setLocation(new Point(ballx++, bally));
jLabel5.setLocation(new Point(ballx++, bally));
jLabel5.setIcon(new ImageIcon("IMG\\ballroll.gif"));
} // equalling PLAIN_SPEED
if(e.getKeyCode()==e.VK_UP) // when the user enters up
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setIcon(new ImageIcon("IMG\\balljetpack.gif"));
} // equalling PLAIN_SPEED
if(e.getKeyCode()==e.VK_DOWN) // when the user enters up
jLabel5.setLocation(new Point(ballx, bally++));
jLabel5.setLocation(new Point(ballx, bally++));
jLabel5.setLocation(new Point(ballx, bally++));
jLabel5.setLocation(new Point(ballx, bally++));
jLabel5.setIcon(new ImageIcon("IMG\\ballroll.gif"));
} // equalling PLAIN_SPEED
if(bally>=340)
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
System.out.println("LOW!!!");
if(bally<=-2)
jLabel5.setLocation(new Point(ballx, bally++));
jLabel5.setLocation(new Point(ballx, bally++));
jLabel5.setLocation(new Point(ballx, bally++));
jLabel5.setLocation(new Point(ballx, bally++));
System.out.println("HIGH!!!");
if(ballx>=594)
jLabel5.setLocation(new Point(ballx--, bally));
jLabel5.setLocation(new Point(ballx--, bally));
jLabel5.setLocation(new Point(ballx--, bally));
jLabel5.setLocation(new Point(ballx--, bally));
System.out.println("RIGHT!!!");
if(ballx<=-3)
jLabel5.setLocation(new Point(ballx++, bally));
jLabel5.setLocation(new Point(ballx++, bally));
jLabel5.setLocation(new Point(ballx++, bally));
jLabel5.setLocation(new Point(ballx++, bally));
System.out.println("LEFT!!!");
if (bally==294 && (ballx > 218 && ballx < 274))
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
if (bally==262 && (ballx > 246 && ballx < 306))
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
if (bally==230 && (ballx > 486 && ballx < 562))
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
if (bally==310 && (ballx > 486 && ballx < 594))
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
if (bally==262 && (ballx > 442 && ballx < 514))
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
if (bally==294 && (ballx > 378 && ballx < 466))
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
jLabel5.setLocation(new Point(ballx, bally--));
// COIN
if ((bally > coiny-10 && bally < coiny+10) && (ballx > coinx-10 && ballx < coinx+10))
coinx = Math.abs(r.nextInt()) % 617 + 1;
coiny = Math.abs(r.nextInt()) % 300 + 1;
jLabel9.setLocation(new Point(coinx, coiny));
System.out.println("Coinx:"+coinx+"");
System.out.println("Coiny:"+coiny+"");
jLabel1.setText(""+ coin++ +"");
System.out.println("Ballx:"+ballx+"");
System.out.println("Bally:"+bally+"");
private void jPanel1_keyReleased(KeyEvent e)
System.out.println("\njPanel1_keyReleased(KeyEvent e) called.");
// TODO: Add any handling code here
jLabel5.setIcon(new ImageIcon("IMG\\ballstanding2.gif"));
private void jPanel1_keyTyped(KeyEvent e)
System.out.println("\njPanel1_keyTyped(KeyEvent e) called.");
// TODO: Add any handling code here
// TODO: Add any method code to meet your needs in the following area
//============================= Testing ================================//
//= =//
//= The following main method is just for testing this class you built.=//
//= After testing,you may simply delete it. =//
//======================================================================//
public void Reminder(int seconds) {
timer = new Timer();
timer.schedule(new RemindTask(), seconds*1000);
class RemindTask extends TimerTask {
public void run() {
System.out.format("Time's up!%n");
timer.cancel(); //Terminate the timer thread
public static void main(String[] args)
JFrame.setDefaultLookAndFeelDecorated(true);
JDialog.setDefaultLookAndFeelDecorated(true);
try
UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
catch (Exception ex)
System.out.println("Failed loading L&F: ");
System.out.println(ex);
new superball();
new Reminder(5);
System.out.format("Task scheduled.%n");
//= End of Testing =
}No, it's because you can't have a constructor called Reminder if you don't have a class named Reminder.
-
Have an object as return type in a method in the WebDynproComponent
Hello together.
I've wrote an EJB in which is a method that read out a DB Table XYZ. In this EJB also are methods to search a single entry.
In my WebDynpro applixcation i have a method in the Component that access the EJB and retrive the single entry for example. In the View implemantation i call the method from the "WEbDynPro component" which have a string as return type.
Is it possible to have an object as return type?
public java.lang.String sr( int KVNR )
//@@begin sr()
KVNummerDTO kvnrObject = new KVNummerDTO();
String Kasse = "";
try
KVNRSessionLocal kVNummerSessionLocal = kVNRSessionLocalHome.create();
kvnrObject = kVNummerSessionLocal.getKVNummer(KVNR);
Kasse = kvnrObject.getKasse();
catch (Exception e)
e.printStackTrace();
wdComponentAPI.getMessageManager().reportException(e.getMessage(), true);
return Kasse;
//@@end
I want to return kvnrObject and not only a string!Hello Micheal,
While Creating a method in front of the return type click on the browse and select Java Native Type Radio Button and again click on the browse button available there. Type the name of the class in the class in it and you can select the return type. If it is a user made class then first the required Java files under the path Resources>src>packages><create a folder>java file. Then build the project so that the class name is visible in list while selecting the return type.
Regards,
Ardhendu -
Native method with String return type
Hi
i am implementing a Native method with String Return type.
i am able call the respective C++ method and my C++ method is printing the String (jstring in c++ code ) correctly
i but i am getting nullpointerexcepti while loading the string in to my Java String .
i am sure my java code calling the C++ code beacause my C++ code is printing the value and one more wonder is after the NPE my c++ code able to print the value
the code follows
HelloWorld.java
public class HelloWorld {
private native String print();
static {
System.loadLibrary("HelloWorld");
public static void main(String[] args) throws InterruptedException,NullPointerException{
HelloWorld hW= new HelloWorld();
for(int i=0;;i++){
String str= new HelloWorld().print();
System.out.println(str);
Thread.sleep(10000);
}and HelloWorld.cpp
// HelloWorld.cpp : Defines the entry point for the DLL application.
#include "stdafx.h"
#include "jni.h"
#include <stdio.h>
#include "HelloWorld.h"
#include <windows.h>
#include "tchar.h"
#include "string.h"
#ifdef _MANAGED
#pragma managed(push, off)
#endif
CHAR cpuusage(void);
typedef BOOL ( __stdcall * pfnGetSystemTimes)( LPFILETIME lpIdleTime, LPFILETIME lpKernelTime, LPFILETIME lpUserTime );
static pfnGetSystemTimes s_pfnGetSystemTimes = NULL;
static HMODULE s_hKernel = NULL;
void GetSystemTimesAddress()
if( s_hKernel == NULL )
s_hKernel = LoadLibrary(_T("Kernel32.dll"));
if( s_hKernel != NULL )
s_pfnGetSystemTimes = (pfnGetSystemTimes)GetProcAddress( s_hKernel, "GetSystemTimes" );
if( s_pfnGetSystemTimes == NULL )
FreeLibrary( s_hKernel ); s_hKernel = NULL;
// cpuusage(void)
// ==============
// Return a CHAR value in the range 0 - 100 representing actual CPU usage in percent.
CHAR cpuusage()
FILETIME ft_sys_idle;
FILETIME ft_sys_kernel;
FILETIME ft_sys_user;
ULARGE_INTEGER ul_sys_idle;
ULARGE_INTEGER ul_sys_kernel;
ULARGE_INTEGER ul_sys_user;
static ULARGE_INTEGER ul_sys_idle_old;
static ULARGE_INTEGER ul_sys_kernel_old;
static ULARGE_INTEGER ul_sys_user_old;
CHAR usage = 0;
// we cannot directly use GetSystemTimes on C language
/* add this line :: pfnGetSystemTimes */
s_pfnGetSystemTimes(&ft_sys_idle, /* System idle time */
&ft_sys_kernel, /* system kernel time */
&ft_sys_user); /* System user time */
CopyMemory(&ul_sys_idle , &ft_sys_idle , sizeof(FILETIME)); // Could been optimized away...
CopyMemory(&ul_sys_kernel, &ft_sys_kernel, sizeof(FILETIME)); // Could been optimized away...
CopyMemory(&ul_sys_user , &ft_sys_user , sizeof(FILETIME)); // Could been optimized away...
usage =
(ul_sys_kernel.QuadPart - ul_sys_kernel_old.QuadPart)+
(ul_sys_user.QuadPart - ul_sys_user_old.QuadPart)
(ul_sys_idle.QuadPart-ul_sys_idle_old.QuadPart)
(100)
(ul_sys_kernel.QuadPart - ul_sys_kernel_old.QuadPart)+
(ul_sys_user.QuadPart - ul_sys_user_old.QuadPart)
ul_sys_idle_old.QuadPart = ul_sys_idle.QuadPart;
ul_sys_user_old.QuadPart = ul_sys_user.QuadPart;
ul_sys_kernel_old.QuadPart = ul_sys_kernel.QuadPart;
return usage;
BOOL APIENTRY DllMain( HMODULE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
return TRUE;
#ifdef _MANAGED
#pragma managed(pop)
#endif
JNIEXPORT jstring JNICALL
Java_HelloWorld_print(JNIEnv *env, jobject obj)
int n;
GetSystemTimesAddress();
jstring s=(jstring)cpuusage();
printf("CPU Usage from C++: %3d%%\r",s);
return s;
}actually in the above code below part does that all, in the below code the printf statement printing correctly
JNIEXPORT jstring JNICALL
Java_HelloWorld_print(JNIEnv *env, jobject obj)
int n;
GetSystemTimesAddress();
jstring s=(jstring)cpuusage();
printf("CPU Usage from C++: %3d%%\r",s);
return s;
}and the NPE i get is
Exception in thread "main" java.lang.NullPointerException
at HelloWorld.print(Native Method)
at HelloWorld.main(HelloWorld.java:10)
CPU Usage from C++: 6%any solution?
Thanks
R
Edited by: LoveOpensource on Apr 28, 2008 12:38 AMSee the function you wrote:
JNIEXPORT jstring JNICALL Java_HelloWorld_print(JNIEnv *env, jobject obj)
int n;
GetSystemTimesAddress();
_jstring s=(jstring)cpuusage();_
printf("CPU Usage from C++: %3d%%\r",s);
return s;
}Here you try to cast from char to jstring, this is your problem, jstring Object should be created:
char str[20];
sprintf(str, "%3d", (int)cpuusage());
printf("CPU Usage from C++: %s%%\r",str);
jstring s=env->NewStringUTF(str);
return s;
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