Problem about interface implementation

Sorry, solved!
Message was edited by:
xixiao

Hi Chris,
Thanks for your reply. I said that it worked but looks like I still have a question.
Can I use an interface type as an instance member. If I do, I get an exception
Exception Description: [MySampleTypeImpl] uses a non-entity [interface MyStatus] as target entity in the relationship attribute.
When I have MySampleTypeImpl defined as under
Class MySampleTypeImpl {
@ManyToOne
MyStatusImpl status;
And I put the interface type in the list of classes in persistence.xml it works fine. But when I have the definition of MySampleTypeImpl as below
Class MySampleTypeImpl {
@ManyToOne
MyStatus status;
Where MyStatus is an interface type I get the exception above. Is there a way out for this.
Thanks and Regards
Anil

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A problem about Interfaces

public abstract interface Business{
        public void growth(String s);
    public class Q3 implements Business{
        public void growth(String f){
    }Above code gives a compile error :
But when I remove public modifier of the interface, it compiled..
Can anyone give the reason for this, please

Do you have those two types in one file?
There may be only one public type (class, interface, annotation or enum) in each file and it's name must be equal to that of the file (minus the ".java" of course).
So if you want a public interface Business it needs to go into a file called "Business.java" and if you want a public class Q3 it needs to go into a file "Q3.java".
If you don't need the type to be public you can put it into another file in this package (but I'd suggest you still put it into its own file, since it keeps stuff simple and easy to find).

Partial Interface Implementation.....am I right?

Hi there everyone,
I am reading Ivor Hortons book, "Beginning Java 2 SDK 1.4 Edition". I have just got to the part where he talks about interfaces. I get interfaces, no problem.....but then he goes on about implementing some methods from an interface and not others. I quote: -
"You can omit the implementation of one or more of the methods from the interface in a class that implements the interface, but in this case the class inherits some abstract methods from the interface so we would need to declare the class itself as abstract"
This is what I think he means (from what I have learned so far)....
An abstract class is a class that that declares methods without actually "filling them in"....it is assumed that this will be done by a sub-class which inherits from this super-class.
Therefore, if you don't implement all the methods in the interface in a class, that class must also be declared as abstract, as you have methods left over that you have not implemented.
Is this right?
He goes on to say that because the class is an abstract class, you can't create instances of this class....unless a sub-class of this class is created that implements the remaining methods. Which seems logical, I guess.....but why would you do this? It seems to be a lot of trouble just to neglect a few methods...they have to be implemented in a sub-class anyway to "arrive at a useful class" as he puts it.
So whats the point?
Also (as an aside)....if you have a class that must enforce method formatting.....why would you use an interface instead of having your class inherit abstract methods from a super-class? Is is because you can only inherit from one super-class (which wouldn't be much use for sub-classes that needed to enforce certain other methods)? I understand that C++ can inherit from multiple super-classes, thus negating the need for interfaces. This seems right to me.
How did I do? :) Any comments?
Thank you.
Jon

An abstract class is a class that that declares
methods without actually "filling them in"....
etc....
Is this right?Pretty much, yep.
He goes on to say that because the class is an
abstract class, you can't create instances of this
class....unless a sub-class of this class is created
that implements the remaining methods. Which seems
logical, I guess.....but why would you do this? It
seems to be a lot of trouble just to neglect a few
methods...they have to be implemented in a sub-class
anyway to "arrive at a useful class" as he puts it.
So whats the point?When you specify the interace, let's call it Foo, you're saying what methods a class must provide if it's to call itself a Foo, but not how do provide that funcionality--that's left up to the actual implementation, as you've learned. For a given interface, there are many ways it could be implemented. However, there may be some common implementations for some of the methods that a family of implementing classes can share--a default implementation that isn't tuned and tweaked for any particular kind of use, but that does work. There may also be some methods for which no reasonable default exists, because it would be too closely tied to whatever your particular implementation is.
For a good example of this, look at the Collections Framework in the java.util package: List, AbstractList, AbstractSequentialList, LinkedList, ArrayList. By the time you get down to either LinkedList or ArrayList, there are only a couple of methods that are left unimplemented. Those methods interact directly with the backing store--i.e. that have to access "array[ix]" for ArrayList or the linked list nodes for LinkedList, so it doesn't make sense to provide a "common" or "default" implementation. The other methods use these methods to do their work, so they don't depend on the particulars of the backing store and hence a common/default implementation is provided for them.

Component interface ( implementation ) is missing

Hello,
I had imported from NWDI one SWC that have some DC's. When I create a project in NWDS form one DC that have a dependence from another DC where the project has bveen already created in NWDS I have the following error message for this DC: "<error: missing compoent> component interface ( implementation ) is missisng". When I delete the referenced DCt from NWDS and sync used DC's from the DC with the error, the problem is solved.
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thanks in advance.

You are absolute right in this, but this is not my problem. I will try to explain it once again. Currently I have the following configuration on my PE router
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interface FastEthernet0/0
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The problem about vrrp

Dear all,I have a problem about vrrp,my core switch is cisco 3750x and huawei S5700-28C-EI, after I configured vrrp between them,the switch log got the error problem as follow:
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If cisco and huawei cannot interconnect with each other?

Can you post the interface config from the huawei and cisco device?
HTH,
John
*** Please rate all useful posts ***

TS1702 I had this Scrabble on my iPad2 and began to have connection problems, it would lock in the "connecting" position. This is not the first time Scrabble has had problems with interface. Typically customers delete the Ap then download it again to rein

I have contacted EA about this and can find no help. I had this Scrabble on my iPad2 and began to have connection problems, it would lock in the "connecting" position. This is not the first time Scrabble has had problems with interface. Typically customers delete the Ap then download it again to reinstall it. During the process you sign in and approve the purchase KNOWING that another window will open saying that you have previously purchased it and that there is no charge. So what happened this time? It will not connect and all of my saved and current games are wiped out. I want my money back, this game interface is pretty junk and operates like some ancient DOS program,,bug,bug,buggy. I want my money back.

Go here:
http://www.apple.com/support/itunes/contact/
and follow the instructions to report the issue to the iTunes Store.
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Hi everyone,
I have a question about interface :
an interface can only have abstract methods, right ?
so how come ResultSet (which is an interface) has methods like next() which can't be abstract otherwise it wouldn't do anything ?
thanks for answering !

an interface can only have abstract methods, right ?Yes. All methods in an interface are inherently public and abstract.
so how come ResultSet (which is an interface) has
methods like next() which can't be abstract otherwise
it wouldn't do anything ?It defines the next() method for classes that implement the interface. When you get a ResultSet reference returned from a method call, you're not getting a reference to an interface; you're getting a reference to an object that implements that interface (or null, as the case may be).

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1. if we r implementing client proxies, it means sap r/3(proxy)->>xi->>>file
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Sreeram,
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If you see this blog by Ravi ( incidentally he is my boss as well ) this is exactly what we have done as well.
/people/ravikumar.allampallam/blog/2005/03/14/abap-proxies-in-xiclient-proxy
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How to register new interface implementation?

Hi,
I have the following problem:
There exists a self written webdynpro application. This application uses a Java Interface. The administrator of the application can add new functionality to the application by adding a new line to a table. He inserts the name of a class which implements that Java interface. This class has the new functionality.
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Now I wonder how I can tell to the webdynpro application that it knows all interface implementations which will come in the future? If I do not "register" or reference the new interface implementations, then I think the webdynpro application has ClassNotFound errors.
The developers should make there own projects for each interface implementation an deploy them. But what must be done, that the webdynpro application knows them?
Can you please give me some suggestions?
Thank you and best regards,
Marcus

You can register a Mac, but not an accessory like the Time Capsule. Keep a copy of your sales receipt.....just in case.

Designs for interface/implementation factory APIs

I've been building a complex data store for geographical information based on JNDI.
The store is basically working but I've been trying to make the API for programs accessing it more regular.
I'm dissatisfied with the way that new objects for addition to the store are instanciated. It's all a bit ad-hoc at the moment so I want to create a proper factory system, separating interface from implementation and allowing for the case where the interface has a different implentation for remote and local contexts.
I'm thinking the best approach would be to have a single create method, probably as a member of the extended context interface.
What I want to get is a sample of how programmers feal about different methods of passing creation parameters to such a factory method (or for that matter, to invite comments on the basic idea).
One possibility would be as a Hashtable or Hashmap. Generic keys (like datastore path) would be defined as constants in the context or factory interface, type specific keys in the interface which is used to access the object being created.
e.g.
Hashtable fsCreate = new Hashtable(5);
fgCreate.put(DataContext.PATH_KEY, "test.features");
fgCreate.put(DataContext.FORMAT_KEY, format);
fgCreate.put(DataContext.BOUNDS_KEY, boundaryRectangle);
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FeatureSetParams fsCreate = new fsCreate();
fsCreate.setPath("test.features");
fsCreate.setFormat(format);
fgCreate.setBounds(boundaryRectangle);
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If there's a create method in the interface, wouldn't
that make it accessible from anything that knows about
the interface? This would nullify the factory
pattern, wouldn't it?Not necesasrilly, that would depend how the create method was implemented. I already have a "retriever" object associated with each implentation class that can be retrieved from the data store. I can add a "create" method, effectively adding a factory class function to these. These retrievers are already registered with the concrete implentation of the JNDI Context.
Granted the implentations are in several different packages, so I can't restrict acces to these retriever objects to the package level.

The Problem about Monitoring Motion using PCI-7358 on LabVIEW Real Time Module

Hello everyone,
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Read Position.flx can execute much faster than 5 ms but as it reads a register that is updated every 5 ms on the board, it reads the same value multiple times.
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An old and difficult problem about "UnsatisfiedLinkError"

Hi dear all,
I have been struck with the problem about "UnsatisfiedLinkError". I have a c++ class HelloWorld with a method hello(), and I want to call it from within a java class. In fact, I have succeeded in calling it on the windows platform. But when I transfer it to linux, the error "UnsatisfiedLinkError" comes out. I have tried to take the measures as Forum has suggested, but it failed.
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"HelloWorld.h"
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#define INCLUDEDHELLOWORLD_H
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"HelloWorld.cpp"
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cout << "Hello, World!" << endl;
"JHelloWorld.java"
public class JHelloWorld
public native void hello();
static
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"JHelloWorld.cpp"
#include <iostream>
#include <jni.h>
#include "HelloWorld.h"
#include "JHelloWorld.h"
JNIEXPORT void JNICALL Java_JHelloWorld_hello (JNIEnv * env, jobject obj)
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All the files are in the same directory and all the processes are under the dirctory:
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4. ld -shared -o hellolib.so *.o
5. java -cp . -Djava.library.path=. JHelloWorld
Exception in thread "main" java.lang.UnsatisfiedLinkError: no hellolib in java.library.path
at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1349)
at java.lang.Runtime.loadLibrary0(Runtime.java:749)
at java.lang.System.loadLibrary(System.java:820)
at JHelloWorld.<clinit>(JHelloWorld.java:7)
Tried another measure:
i) export LD_LIBRARY_PATH=.:$LD_LIBRARY_PATH
ii)java -cp . JHelloWorld
The same error came out as above.
I really don't know what is wrong with it.
Would you like to help me as soon as possible?
Thanks.
Regards,
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Hi Fabio,
Thanks a lot for your help.
It is very kind of you.
Regards,
Johnson

A problem about calling Labview vi in VB

Hi all:
I meeting a problem about data transfer and parallel operation between VB and Labview.
Actually, I want develop a VB program, in which, the Labview VI can be called and corresponding parameters can be transferred to Labview. and then, I also can operate my system by VB program at same time. something like parallel operation (VB and Labview program).
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Does anybody know something about it? Thanks a lot
Message Edited by hanwei on 11-07-2008 03:18 PM
Attachments:
vb_labview_error_message_1.JPG ‏14 KB
VB_to_LV.zip ‏10 KB

I sure hope OP has solved it by now.
/Y
LabVIEW 8.2 - 2014
"Only dead fish swim downstream" - "My life for Kudos!" - "Dumb people repeat old mistakes - smart ones create new ones."
G# - Free award winning reference based OOP for LV

HT201210 hi everyone, i have a problem about my iphone 4S, doesn't work with wifi connection and bluetooth since upgrade to the IOS 7.0.3. Can anyone can help me tosolve this problem?????Thank's regards paulus

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Try the suggestions here to see if they resolve your problem:
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NetWeaver 2004s --- XI
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SAP Help Document über File Adapter
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Help Docu

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http://help.sap.com/saphelp_nw04/helpdata/en/44/f565854b7341e6e10000000a1553f6/frameset.htm
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<a href="/people/michal.krawczyk2/blog/2005/06/28/xipi-faq-frequently-asked-questions"><b>XI / PI FAQ - Frequently Asked Questions</b></a>

Problem about interface implementation

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