Optional implemenation for interface methods?

hi, is there a way of putting several methods of a
interface to optional implemenation? such as one
method name but different parameters, and put all of
them to optional implemenation for classes that
implements the interface? thanks :DNo.
If a class implements that interface, then it must either implement all the methods, or declare itself abstract.
You can do like the various XxxAdapter classes to in Swing. Create a concrete class that implements the interface, and give all its methods empty bodies. A subclass then overrides only those methods that it wants to actually do something with.
Note that I don't think this approach is usually a good one. If there are some methods that are optional, then maybe they should be in different interfaces, and classes can implement various combinations of your interfaces.

Similar Messages

Access specifiers for interface methods

When we implement the interface ,we have to specify the implementing method access specifier to be "PUBLIC" ,but not "PROTECTED" or "PRIVATE".
Compiler is giving an error -- attempting to assign weaker access privileges ,when we specify protected.
what is the internal reason for this?Why we shouldnt make the access weaker in the implementing class.
Can any one help me on this.Your help is highly appreciated.

When we implement the interface ,we have to specify
the implementing method access specifier to be
"PUBLIC" ,but not "PROTECTED" or "PRIVATE".
Compiler is giving an error -- attempting to assign
weaker access privileges ,when we specify protected.
what is the internal reason for this?There is absolutely no point in having a private interface method. The interface represents a visible abstraction and private methods are never visible so it is a contradiction in terms.
An interface is intended to represent an abstraction that a user (software) uses. Protected via child/parent represents a usage that is restricted to a child from a parent. The child can already see the parent so there is no point in having an abstraction for the child. And it would probably be unwise to limit a child by such an abstraction.
Protected via the package and interfaces is more contentious as to why it is not allowed. There are those that argue that this should be allowed so that a package can use interfaces but restrict them to the package. To me this seems like a minor point given that most interfaces will probably represent an abstraction to other packages and not within a single package. This applies specifically to default access as well.

JDBC - Optional support for certain methods

According to the notes on http://java.sun.com/products/jdbc/driverdevs.html (Section A.2.1) a method that is inappropriate for the underlying DBMS may throw SQLException. Presumably the text associated with this exception would indicate that the method is not supported. However, the actual text used is not defined. Indeed, how can it be if full internationalisation is to be accounted for?
And so to my dilemma...
Let's say I want to write a generic wrapper for any JDBC driver and somewhere in my code I want to invoke PreparedStatement.setBigDecimal(). This method must be implemented but isn't necessarily supported. [ The JDBC driver supplied by SAS Institute is an example of this. ] When invoked, this method throws SQL Exception unconditionally.
What I want to be able to do is to determine in advance whether or not this method, or indeed any of the optional methods, is supported.
There are certain useful methods available in the implementation of DatabaseMetaData but nothing to help me in this particular case.
It's no good catching the exception because there's no well-defined way to interrogate the exception's message String to determine how or why it was generated.
Am I missing something here or is this really a "hole" in the standard?

Am I missing something here or is this really a "hole"
in the standard? You are missing something.
You are assuming that there is some sort of real standard compliance for JDBC drivers.
There is not.

Interface method not implemented by class :(

I'm getting an error for interface method
Interface method handleLogout in namespace views.interfaces:IWiseMediator not implemented by class views.mediators:RatingViewMediator.    RatingViewMediator.as
package views.interfaces
    import flash.events.Event;
    public interface IWiseMediator
        function handleLogout(event:Event):void;
but I done this in RatingViewMediator
private function handleLogout(event:Event):void
            viewObject.clearFields();

interfaces are used to enforce a public 'interface' to the class. as a private method can only be accessed by the class itself, it doesn't make sense to include private methods in an interface.

Select-options for OO Methods

Hi all,
How can I define select-options for a method in a global class.
And how can I pass these select-options from a report.
Thanks & Regards
Eshwar

Hi all,
How can I define select-options for a method in a global class.
And how can I pass these select-options from a report.
Thanks & Regards
Eshwar

How to set transaction isolation level for a method in a Local Interface

 By reference at:
 http://e-docs.bea.com/wls/docs61/ejb/reference.html#1071267,
 the value for method-intf can only be "Remote" or "Home".
 My question is--
 How to set transaction isolation level for a method inside a Local Interface or
 Local_Home Interface?
 Thanks.
 Xing


I'd try 6.1SP2. I'm pretty sure this works now.
 -- Rob
 Xing wrote:
 > I tried "Local", but got an error when deploying the EJB jar, saying that only
 > "Remote" or "Home" is allowed.
 >
 > Any idea?
 >
 > Xing
 >
 > Rob Woollen <[email protected]> wrote:
 > >
 > >
 > >Use LocalHome or Local.
 > >
 > >-- Rob
 > >
 > >Xing wrote:
 > >
 > >> By reference at:
 > >> http://e-docs.bea.com/wls/docs61/ejb/reference.html#1071267,
 > >> the value for method-intf can only be "Remote" or "Home".
 > >>
 > >> My question is--
 > >>
 > >> How to set transaction isolation level for a method inside a Local
 > >Interface or
 > >> Local_Home Interface?
 > >>
 > >> Thanks.
 > >>
 > >> Xing
 > >
 > >--
 > >
 > >----------------------------------------------------------------------
 > >
 > >AVAILABLE NOW!: Building J2EE Applications & BEA WebLogic Server
 > >
 > >by Michael Girdley, Rob Woollen, and Sandra Emerson
 > >
 > >http://learnWebLogic.com
 > >
 > >
 > >
 > >
 > ><!doctype html public "-//w3c//dtd html 4.0 transitional//en">
 > ><html>
 > >Use LocalHome or Local.
 > >-- Rob
 > >Xing wrote:
 > ><blockquote TYPE=CITE>By reference at:
 > > http://e-docs.bea.com/wls/docs61/ejb/reference.html#1071267,
 > > the value for method-intf can only be "Remote" or "Home".
 > >My question is--
 > >How to set transaction isolation level for a method inside a Local
 > >Interface
 > >or
 > > Local_Home Interface?
 > >Thanks.
 > >Xing</blockquote>
 > >
 > ><pre>--
 > >
 > >----------------------------------------------------------------------
 > >
 > >AVAILABLE NOW!: Building J2EE Applications & BEA WebLogic Server
 > >
 > >by Michael Girdley, Rob Woollen, and Sandra Emerson
 > >
 > >http://learnWebLogic.com</pre>
 > > </html>
 > >
 > >
 AVAILABLE NOW!: Building J2EE Applications & BEA WebLogic Server
 by Michael Girdley, Rob Woollen, and Sandra Emerson
 http://learnWebLogic.com
 [att1.html]

No static methods for Interfaces ?

Hi,
I was going though some documentation about the interfaces and it says that, an interface methods must not be static.
Can someone please explain or direct me in the direction which tell me why the internet methods cannot be static.
Thanx.
Mel

Defining a static method in a interface would be useless, since static methods can't be executed with dynamic binding. You'd have to know the name of the implementing class of the interface at compile time to call it, which would negate the need for an interface.
For more details google it, that question has been asked thousands of times.

2 interfaces for one method ???.

Hi, anybody can see what will happen if we implemented two interfaces , each of which have a method named e.g. move()for example, Cowboy and Shape.
Thanks
Mario

If the methods in the different interfaces have
different parameters or the same return type, it's not
a problem. Otherwise a compile-time error occurs.
shakes head Nope. Consider the following code:
// File = TestI.java
public interface TestI
    public void test();
// File = TestI2.java
public interface TestI2
    public void test();
// File = Test.java
public class Test
    public static void main(String arg[])
        new Test().test();
    public void test()
        System.out.println("Hello, world!!");
}This code both compiles and runs. A compile-time error will probably result if the two interfaces specify different return types for their methods (a supposition that I have not yet tested). The only real problem with doing this, however, is that the interfaces may dictate two entirely different (and possibly contradictory) actions.
Best bet is to name your interface methods more distinctly. The method name "move" isn't incredibly descriptive.

HT1657 Have a $15.00 credit and wish to rent a movie on Ipad but am being asked for payment method and redemption is not an option.

Have a $15.00 credit and wish to rent a movie on Ipad but am being asked for payment method and redemption is not an option. Any suggestions?

To Contact iTunes Customer Service and request assistance
Use this Link > Apple Support iTunes Store Contact

Design options for interfacing RFC as Receiver

hello guys ,
Need some ideas in developing a scenario for interfacing RFC as receiver from a stored procedure call on DB side , what would be best and easy way to interface this RFC?
Best regards
Krishna

hi,
but what do you need to know?
you can call stored procureude with sender jdbc adapter
and put the data via RFC
it's better to use an abap proxy but if you cannot use the rfc
you don't need any BPM as this is a jdbc - rfc flow
Regards,
michal

Response options for POST method in Restufl services?

I am using the Restful services for the Oracle Cloud Database and I am trying to see what my options are for returning responses from my POST calls but haven't had any luck. It doesnt seem that using dbms_output.put_line() is respected for returning information in the body of the response and I havent had any luck with OUT parameters. Obviously GETs work fine returning the selected dataset, but I can't figure out what to do for POSTs. Can someone give me a quick simple, PL/SQL hello world example of returning data (body or header, either is fine) for the REST APIs?
Edited by: 1003431 on Apr 30, 2013 3:56 PM

user588066 wrote:
Thank you for your response,
I constructed HTML data in different ways, but in all cases I am getting 200(OK) response. But nothing is happening As I mentioned, you must not construct HTML for a POST.
A POST consists of two basic parts. A header part. A data part.
The POST that you need to create, should look something as follows:
POST /servlet/servlet.WebToLead HTTP/1.1
Host: www.salesforce.com
User-Agent: Mozilla/4.0
Content-Length: <number>
Content-Type: application/x-www-form-urlencoded
oid=00D400000008XSQ&first_name=Scott&last_name=Tiger&email=[email protected] header part contains the standard HTTP header information - such as the size, content type and so on.
The data part contains what a query string for a GET command typically would contain. Name-value pairs, separated by the ampersand character, and control characters encoded where needed.
I suggest that you use your favourite search engine and research the topic of what the content and structure is for a http POST - and once you understand that, put some PL/SQL code together to create such a structure. And make that simplistic first so it is easy to debug and test - before tackling a more complex POST using https in addition too.

Interface (Methods Public ????)

hello friends,
In interface , Y are the methods default declared as public???? and Y cannot we declare them as friend or protected ?
Can anybody tell me in details abt the same ????

Declaring protected would be unusual too since only
descendants can access protected methods and an
interface cannot have descendants of course you mean only descendands and classes
in the
same package can access protected methods ... :)Well yes, though redundant for this argument since that is already covered by package-private access. The difference between the two access-levels, the descendants, is an empty set for interfaces.
This should act a response to the previous post also - because it would make no sense to allow protected. I can see, and demonstrate, cases where package-private is of value however.
Sun made the decision it seems without full consideration. They cannot now change that decision because of the implicit manner in which package-private is indicated to the compiler (by the absence of another access level). That's a problem since the compiler automatically infers 'public' access for methods in interfaces in cases where the grammar would normally indicate package-private. Changing this would break a massive amount of code.
An option would be to introduce a new keyword 'friendly' or 'packageprivate' and keep the current rules for implied access. This would allow the new access without breaking much code. The only code to break would be that which uses the new keyword for another purpose.
These collisions would be uncommon because:
- The name of a type uses the convention of a leading uppercase first letter.
- The name of a method uses the conventions for property accessors and
mutators using the prefixes 'get', 'set', 'is' and 'has' or is a behaviour and
more likely to use a verb.
local variables and fields are the only likely collisions - these should be minimal and not used in exposed APIs.
Talden

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,
Pablo

It 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

Is there a (relatively simple) way to skip tracks with an iPod touch 5th gen using a physical button? I'm aware songs can be skipped on-screen without unlocking the iPod, but I'm looking for a method that doesn't require taking my eyes off the road.

Is there a (relatively simple) way to skip tracks with an iPod touch 5th gen using a physical button? I'm aware songs can be skipped on-screen without unlocking the iPod, but I'm looking for a method that doesn't require taking my eyes off the road while driving. For that reason, I'm also not interested in adding in headphones or additional devices that have the desired button functions. Going both forward and back would be great but I would be pleased just to have a "sight-free" way to go forward.
I've seen some mention here and there about ways to maybe change it so the volume buttons change tracks and holding the volume buttons changes the volume... but I don't know what's involved in that or if its even possible/recommended for a new 5th gen iPod. I think its a great device but its sadly lacking in music oriented functions and features... which is disappointing since music is why most people would bother getting one instead of some other "iDevice" :/

Given that you cannot do what you have asked for, perhaps you simply need to find another solution to your root problem.
Presumably, you want to skip to the next track because you don't want to hear the current one, and that is because...
You don't like it.
You've heard it recently and don't want to hear it now.
Simply don't want to hear it at this time.
For problem number 1. Don't put it on the iPod in the first place. (I know, obvious answer!)
For problem number 2. How about playing from a Smart Playlist (initially created in your iTunes Library) which has only songs you've not played recently?
For problem number 3. Hhhmmm! Create alternative Playlists for use in the car.
As for going back to the start of the "now playing" track.... Well, if your Playlist has only songs that you really, really want to hear, then you'll be looking forward to that rather go back to the beginning of the current song.
I'm not trying to be prescriptive, just giving you food for thought.
(They are all cheaper options than buying a car which can control the iPod from the steering wheel.)

Please do not enter data for payment method Cheque papel error in IT0009

Hi Experts,
Whenever i try to maintain bank details infotype for payment type C(Check Papel),the system is throwing error "Please do not enter data for payment method Cheque papel". As per SAP std, I had deleted the entries for bank key, bank account and bank control key and maintained IBAN field in IT0009.While saving i am getting the error""Please do not enter data for payment method Cheque papel" and I couldn't save the record.
Then i deleted the entries for bank key, bank account and bank control key and IBAN field also in IT0009. While saving i am getting the error "Fill in all required entry fields". System behaves as if Iban a required field in IT0009. Our bank details infotype is country specific.We made it country
specific through feature P0009 and setting in table T588M.As per our conf setting IBAN field is optional. Even though IBAN field is optional, this field behaves as that of a mandatory field in IT0009.Iam facing this issues only for a few countries like Spain,Italy etc.For other counties i am able to change of create Bank details record for payment type C.
I have checked in Payment Methods by Country in FBZP (Payment Method Classification is set to Check and BANK DETAILS box is unchecked) but still no solution. Do i need to check in any other setting.
Please shed some light on this issue.Thanks in Advance.

Hi Jobish,
It's weird but I tried the below method and it works
Here's what you can try in case you do not want to enter the bank details for payment method 'C'..
Tcode FBZP - > payment methods by country - > select payment method as 'C' and make below changes (make a note of these changes as you will have to undo them after saving the table):
a. Payment method by classification - select bank transfer
b. Reqd master record specifications - check the bank details options and select the options which you want to be entered (a/c no required, IBAN rqd, SWIFT code rqd)
Save the table.
PA30- > Edit any record once again and save it.
Again go to FBZP and undo the above changes, i.e, revert to the original entries and again save the table.
Try editing the record now in PA30 and it allows to save. This is the second weird workaround that I have come across and still not sure why
After above workaround, I didn't get any error while maintaining the record, for this or any pernr.
See if it works.
Regards
Neha

Optional implemenation for interface methods?

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