Language inheritance and Xbase

Hi
Say that I have an extension of Xbase, call it XB1, with a new
expression, and thus, with a custom type computer and custom xbase
compiler handling the new expression, and then are specified in the
runtime module.
Now I define a new language XB2 which inherits from XB1. I just
realized that the runtime module for XB2 does not inherit from the one
of XB1, so the bindings for the xbase compiler and the xbase type
computer must be explicitly redefined in the runtime module of XB2.
I guess this manual specification in the runtime module cannot be
avoided, can it?
thanks in advance
Lorenzo
Lorenzo Bettini, PhD in Computer Science, DI, Univ. Torino
HOME: http://www.lorenzobettini.it
Xtext Book:
http://www.packtpub.com/implementing-domain-specific-languages-with-xtext-and-xtend/book

On 30/07/2015 19:03, Sebastian Zarnekow wrote:
> Hi Lorenzo,
>
> there is no built-in facility to avoid that. You could extract the
> necessary bindings into an own module and call that one from all your
> runtime modules by means of binder.install(..)
>
> Best,
> Sebastian
Hi Sebastian
thanks for the suggestion, but that won't work for bindings that have
already been defined in the generated abstract runtime module...
If I understand correctly what you're suggesting, you say (recall XB2
inherits from XB1 which has some custom Xbase classes, like type
computer, compiler, etc, that I want XB2 to reuse):
public class XB2RuntimeModule extends
xjbase.example.purexjbase.AbstractXB2RuntimeModule {
@Override
public void configure(Binder binder) {
super.configure(binder);
binder.install(new XB1InstallableRuntimeModule());
where XB1InstallableRuntimeModule has bindings of the shape
public Class<? extends IGenerator> bindIGenerator() {
return XB1JvmModelGenerator.class;
public Class<? extends XbaseCompiler> bindXbaseCompiler() {
return XB1XbaseCompiler.class;
is that right?
So XB1InstallableRuntimeModule has only the bindings for the Xbase
custom components.
Unfortunately this will generate runtime errors since Guice will
complain that a binding for IGenerator is already defined (indeed it's
in the AbstractXB2RuntimeModule), while it works for bindXbaseCompiler
since there's no explicit binding for that.
As an alternative solution I override XB2StandaloneSetup.createInjector
as follows
@Override
public Injector createInjector() {
return Guice.createInjector(
Modules2.mixin(
new XB2RuntimeModule(),
new XB1InstallableRuntimeModule()));
and this works! :)
Does this make sense?
thanks in advance
cheers
Lorenzo
Lorenzo Bettini, PhD in Computer Science, DI, Univ. Torino
HOME: http://www.lorenzobettini.it
Xtext Book:
http://www.packtpub.com/implementing-domain-specific-languages-with-xtext-and-xtend/book

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Inheritance and access control - "private protected"

I'm reopening an old topic, seems to have been last discussed here 2-3 years ago.
It concerns the concept of restricting access to class members to itself, and its subclasses. This is what "protected" does in C++ and "private protected" did in early versions of the Java language. This feature was removed from Java with a motivation along the lines of not being "simple", and "linear" (in line with the other access modes, each being a true subset of the next). Unfortunately, the article which explained Sun's position on this keyword combination seems to have been removed from the site, so I haven't been able to read its original text.
But regardless of simplicity of implementation or explaining Java's access modifiers to newbies, I believe it is a fundamental part of OO programming for such an access mode to exist. The arguments for having the standard "private" mode in fact also apply for having a C++-style "protected" mode. (Arguing that classes within a package are related and it therefore doesn't hurt to also give them access to Java's "protected" members, is equally arguing that "private" is unneccessary, which noone of course believes.)
The whole concept of inheritance and polymorphism and encapsulation builds on the access modes private, protected, and public (in the C++ senses). In Java the "package" concept was added - a nice feature! But I see no justification for it to negate the proper encapsulation of a class and its specializations.

What effect upon inheritance other than hiding members
from subclasses is there?
None. And I cant think of another declaration that prevents members from being inherited but private.
Of course the onus comes on the programmer with Java's
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1) there is rarely a single programmer working within
a package
The point was the package is a unit which does not hide from itself. Just like all methods within a class can see each other, all classes within a package can, and all packages within a program can.
2) it muddies the encapsulation in the design - when
you see a "protected" method someone else, or yourself
some time ago - wrote, how do you know if the design
intention is to have it accessed solely by the class
and its subclasses, or if it is indeed intended to be
shared with the whole package? The only way to do
this today is to always explicitly specify this in the
comments, which may be lacking, inconsistent, and
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I understand where you are coming from, but I really have not had occasion to take issue with it. I can't think of a real codeing situation where this is required. OTOH, I can't think of a coding situation where I need to access a protected method from another class either.

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Hello,
My question is a bit complicated, so let's first explain the situation with a little pseudo code:
class A {...}
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class C extends B {...}
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multiple inheritance and interfaces
http://www.javaworld.com/javaqa/2002-07/02-qa-0719-multinheritance.html
http://java.sun.com/docs/books/tutorial/java/interpack/interfaceDef.html
http://www.artima.com/intv/abcs.html
http://www.artima.com/designtechniques/interfaces.html
http://www.javaworld.com/javaqa/2001-03/02-qa-0323-diamond_p.html
http://csis.pace.edu/~bergin/patterns/multipleinheritance.html
http://www.cs.rice.edu/~cork/teachjava/2002/notes/current/node48.html
http://www.cyberdyne-object-sys.com/oofaq2/DynInh.htm
http://www.gotw.ca/gotw/037.htm
http://www.javajunkies.org/index.pl?lastnode_id=2826&node_id=2842
http://saloon.javaranch.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic&f=1&t=001588
http://pbl.cc.gatech.edu/cs170/75
Downcasting and run-time
http://www.codeguru.com/java/tij/tij0083.shtml
type identification
Since you lose the specific type information via an upcast (moving up the inheritance hierarchy), it makes sense that to retrieve the type information ? that is, to move back down the inheritance hierarchy ? you use a downcast. However, you know an upcast is always safe; the base class cannot have a bigger interface than the derived class, therefore every message you send through the base class interface is guaranteed to be accepted. But with a downcast, you don?t really know that a shape (for example) is actually a circle. It could instead be a triangle or square or some other type.
To solve this problem there must be some way to guarantee that a downcast is correct, so you won?t accidentally cast to the wrong type and then send a message that the object can?t accept. This would be quite unsafe.
In some languages (like C++) you must perform a special operation in order to get a type-safe downcast, but in Java every cast is checked! So even though it looks like you?re just performing an ordinary parenthesized cast, at run time this cast is checked to ensure that it is in fact the type you think it is. If it isn?t, you get a ClassCastException. This act of checking types at run time is called run-time type identification (RTTI). The following example demonstrates the behavior of RTTI:
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import java.util.*;
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public void g() {}
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public void f() {}
public void g() {}
public void u() {}
public void v() {}
public void w() {}
public class RTTI {
public static void main(String[] args) {
Useful[] x = {
new Useful(),
new MoreUseful()
x[0].f();
x[1].g();
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I found a case where "super" is not working as I understand it should...
Can someone explain me the underlying theory that makes JAVA behave this way??
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THANKS!!

IgnacioKriche wrote:
But I used "super", so this means to use the methods of the super class and I understand that a method called within another, is part of this last one. this is:
if inside method 'x', method 'y' is called, then 'y' is part of 'x' . Agree? And therefore since I am using super I'm saying use 'x' method from super class since 'y' is part of 'x' then super applies for 'y' as well so what is method from the extended class doing here? It's like we have a mix between the 'x' from super and 'y' from the extended. Something like super only applies for the first level not at a deeper level (a method called from another)No. Just because the base class method2() invokes method3() does NOT mean it will always invoke base's version of method3. If it did that, then polymorphism would definitely be broken.
You explicitly invoked super.method2(), so that told the compiler to explicitly use the base class version of that method. But then method2 in the base class invokes method3(). That ends up invoking the overridden version in the subclass, by design, because afterall the actual object whose methods are being executed is a subclass instance. If it didn't do that, then polymorphism would be broken for everyone else.
If you think you need the behavior you are looking for, you are just designing it wrong in the first place.

Language Inheritance

Hi All,
Do we need to configure the Primary and Secondary language any where in the console?
Let's take an example i have English[US] -
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I have 4 more languages which are English[UK] --- Data Not maintaing
German ---data maintaining
French --- Data Not Maintaining
Russian---data not maintaining
In this scenario do i need to set up anything to take the English[US] -
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the same case with German and French .
German -
Primary Inheritance to ---French
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Please let me know ASAP.

Hi Priya,
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Hope this would be helpful..
If helpful do reward Points!!!!!!!!!!!!
Regards,
Parul

Difference between inheritance and abstract class

difference between inheritance and abstract class

See this thread:
http://forum.java.sun.com/thread.jspa?forumID=24&threadID=663657
And before Post New Topic, just search in this forums. All most will get answers.

Problem with inheritance and outputting values in toString.

Hey guys, i'm having a major problem with inheritances.
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http://www.4shared.com/file/ZleBitzP/Assign7.html
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Basshunter36 wrote:
Hey guys, i'm having a major problem with inheritances.
What i'm trying to do with my program is to create objects in my demo class. Values are passed to several other objects that each do their own calculations of grades and results and then outputs the result in my toString. I followed step by step the instructions in my book on how to setup the inheritance and such. I can only output everything that was created in my superclass, any other thing that was created in an object that belongs to a subclass does not display in the output at all.
Even if I change or create new instance variables, I can't figure out for the life of myself how to output the other values.No idea what you're talking about. Provide an [url http://sscce.org]SSCCE.
Because there's so much code to be splitting on the forums, I zipped my whole project in a RAR. I'll link it here
http://www.4shared.com/file/ZleBitzP/Assign7.html
Not gonna happen. Provide an [url http://sscce.org]SSCCE. And don't say you can't. You definitely can. You may have to spend an hour building a new program from scratch and getting it to reproduce the problem, but if you can't or won't do that, you'll find few people here willing to bother with it.

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Another problem I want to report is my iPhone 5S (iOS 8.0.2) Bluetooth connection, which has a big issue. Since iOS 8.0.2 upgrade, I could not use my Bluetooth anymore. My device can be found from other devices, such as my Macbook Pro, for example, however, I am not able to pair or even find any other device from my iPhone to others.
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Shut down your computer and disconnect all peripherals (keyboard & mouse if pertinent) from your computer. Now reboot.
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If none of the above works, again disconnect all peripherals from your Mac, hold down the "shift" key to start up in "Safe Boot" mode.
If the Mac starts up correctly, restart without pressing the "shift" key.
If your computer still does not start up properly, shut it down and restart it while holding down the Apple+Option-P-R keys; keep holding "all 4 keys" down until you hear the startup sound "twice."
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Select your language.
Once on the desktop, select Utility in the menu bar.
Select Disk Utility.
Select the disk or volume in the list of disks and volumes, and then click First Aid.
Click Repair Disk.
(If Disk Utility cannot repair, you will need a stronger utility (3rd party) - Diskwarrior or Techtool PRO)
Restart your computer when done.
Repair permissions after you reach the desktop-http://docs.info.apple.com/article.html?artnum=25751 and restart your computer.
Remove any 3rd party ram.
Reinstall Leopard - This will install a "fresh" copy Leopard without archiving old system files but leaves the rest of your files in place.
If you still want to restore your computer to factory level...
Start up from your install disc, go to Disk Utility and select the disk and click erase - to securely erase data click Security Options and Erase Free Space which will entirely wipe your disk, overwriting it with zeros so that no data is recoverable.
To restore read the instructions in the Mac OS X v10.5 Leopard - Installation and Setup Guide PDF

How to install photoshop cc in several languages, Spanish and English

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In
Re: Change language?
PECourtejoie posted this Link:
Installing Multiple Languages of a Desktop Application | CS6 & Creative Cloud Feature Tour for Design | Adobe TV

I know c,c++ and java language ! and i want to contribute for development of mozilla products ! any idea where i can find beginner level projects ?

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You could also try jumping in on some of the Mozilla IRC chat channels as was suggested to someone else in another thread.
Also you could also try the [/forums/buddies new contributors forum], it does now have an Admin monitoring and replying. (At the time of the quoted post Admins were almost impossible to get hold of for forum matters )
''Noah_SUMO [/forums/buddies/710569#post-61671 said]''
<blockquote>
Sorry I didn't see this earlier. :)
I know just the places where I think you'd fit in best. To make sure, just join us in #sumodev and #mozwebqa and #communityit at irc://irc.mozilla.org
I think your skills in php, javascript, python and server admin-y stuff will come in real handy at these places. :D
For example, some help is needed here to fix these tests after a new theme was added to wiki.mozilla.org and they are in python. https://github.com/mozilla/wiki-tests - more info in #mozwebqa
And maybe some help with perl might be needed with firebot, a irc bot written in perl. Channel #firebot for that.
And #communityit (for server admin stuff) and #sumodev could use some help as well, just pop in and ask. :)
</blockquote>
Also see
* [[Contributor News & Resources#w_communication-channels]]_communication-channels
** Mibbit link (this one for #sumo channel ) https://www.mibbit.com/?server=irc.mozilla.org&channel=%23sumo
P.S. and see
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When to use inheritance and When to use Composition

java support both inheratiance and composition .I also know "is a" and
"has a realitionship" but there is always a problem with me to understanding whethere i have to use extends or having a object of a class has a member of othere class.
and also "A pure OOP must support polimorphisim,inheretiance,encapluction,Abstraction and Composition" correct me if i am wrong
thank you and have a nice day.

Bruce Eckel, author of Thinking In Java, has this to say about composition vs. inheritance:
When deciding between inheritance and composition, ask if you need to upcast to the base type. If not, prefer composition (member objects) to inheritance. This can eliminate the perceived need for multiple base types. If you inherit, users will think they are supposed to upcast.
Choose composition first when creating new classes from existing classes. You should only used inheritance if it is required by your design. If you use inheritance where composition will work, your designs will become needlessly complicated.
Bill Venners: Composition versus Inheritance
Use inheritance (of implementation) only when the class satisfies the following criteria:
1) "Is a special kind of," not "is a role played by a";
2) Never needs to transmute to be an object in some other class;
3) Extends rather than overrides or nullifies superclass;
4) Does not subclass what is merely a utility class (useful functionality you'd like to reuse); and
5) Within PD: expresses special kinds of roles, transactions, or things.
-- from Java Design: Building Better Apps and Applets (2nd Edition), by Peter Coad and Mark Mayfield

When to use inheritance and when not to?

I've just been trying find out when to use inheritance and when not to use inheritance? I know that inheritance gives advantages such as code reuse and maintainability. But when are their times not to use inheritance that may effect the design of a project?
Also when should one consider aggregation over inheritance(is-a relationship)?
thanks,
plandis

Hi
Answering this question usually requires a few books, so, I'm sorry, it's not really as simple as choosing between using a screwdriver vs. a hammer.
But, very short, inheritance should ideally only be used when there exist a strict 'is-a' relationship. However, sometimes it may be clever to inherit when you have a 'is-almost-a' relationship... And sometimes this is a stupid move. This depends on the context/circumstances.
Aggregation is normally considered a 'has-a' relationship, thereby differing clearly from inheritance. The old 'car' model says "a car is-a vehicle and has-some (at least) wheels."
The wheels are aggregated to the car class, that itself is inherited from vehicle.
However, this is just a good rule-of-thumb and there may be circumstantial reasons for not following these guidelines.

Language inheritance and Xbase

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