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If you write everything from scratch, you will have more control by definition.
If you use a code generator you may (depending on the code generator) get better or more consistent code quality, and you will definitely save time.
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What about the performance issues?
Will the code generator not weigh down the application?
Oh and is there any difference a code generator and a template (for an application)? Also is there a relation between the two?
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All occasions I've seen and used code generation tools, that's been a build-time issue, not run-time. You run the tool to create code, which is included in the compiling and build of the software. As such, there's no performance penalty when running, although it can complicat the build process.
For instance, Microsoft has a tool that takes an XML file and creates an XML schema from it. This schema can then be run through the same tool which can generate C# classes to represent it. This means you don't have to hand code the classes needed to serialise the XML, but have used a code generation tool. Typically, you'd only do this when there's been a change in the XML schema, not every time you build the system.
I'm not entirely clear what you mean by template here? Do you mean the different application and library types you can pick from when creating a new project in Visual C#? Those templates are effectivel recipes used by the code generation tool to create the project and its initial files.
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I very much dislike generated code. If you need so much code to accomplish something that you feel the need to generate it, there is a more fundamental problem that needs addressing, perhaps in the language or choice of technology.
I don't include code which is generated from a non-text editor, like WinForms designer files or WPF/Silverlight XAML. You're still in charge of that, it's just the text editor isn't your usual editing environment. But the abominations that Microsoft create for you when you communicate with a COM or WCF server are fairly clear indications that they need to provide better tools to access those technologies.
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The more experienced a developer is, the less likely they are to use any kind of generator.
Snippets as templates will get used, but not generated code.
I wasn't, now I am, then I won't be anymore.
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But is it not true that developers at entry level have to use a much more hands-on approach, whereas developers at a higher level will have to concentrate on the design of the application from an architectural point of view.
Also as you reach a higher level your responsibilities will increase. Will you use up more of your time by manual coding when you can save your time with a good code generator?
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Phanindra261 wrote: a good code generator
When I first started out as a developer many years ago, I thought that a code generator was a time saver and a great idea. The more experienced I got, the more I realized that code generators end up costing more time than an experienced developer writing it right the first time. Troubleshooting code from a generator is very often far more time consuming.
I have mentored a few developers over the years and I always try to steer them away from using "the easy button" because you don't learn much in development without doing the work yourself. So all in all, I don't like generators at all and I've found that most seasoned developers have tended to come to the same opinion I have of them. Cheers.
I wasn't, now I am, then I won't be anymore.
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What a load of rubbish, you should be using a code generator where it is a valid tool for the job. Coding up the DAL layer is just crazy, coding up the model is just as dumb. Generating code for VM or the VIEW is impossible.
Obviously we are using Silverlight but the code generator we use started life as a VB5 tool in the 90s, it is called ClassBuilder, I pinched it from the lead developer on that project and have rewritten it a dozen times. It does the CRUD stored procedures, the Model (based on a view of the table) and the DAL. Half a dozen click and I have my WCF written.
We tried writing something for the VM and the View but that is where the hand coding is required.
Never underestimate the power of human stupidity
RAH
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Mycroft Holmes wrote: Coding up the DAL layer is just crazy
I disagree. In my opinion, DAL code that can be generated shouldn't exist at all.
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What about your standard CRUD operations?
Never underestimate the power of human stupidity
RAH
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It depends. I'm generally not a fan, but I'm old-school.
Something like Linq-to-SQL will generate SQL code for you; if you're no good at writing SQL, then using it may be of benefit; if you are good at writing SQL, it may not be. (I don't use it.)
Other than the WinForms designers, the only code generators I use are ones I wrote to perform certain tasks for me:
GenOmatic[^]
Implanting Common Code in Unrelated Classes[^]
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suppose I have a class A, and the interfaces I1 and I2.
Interfaces I1 contains methods a,b
Interfaces I2 contains methods a,b,c and d
class A can implements I1 or I2 depending on how it is constructed.
Question, what is the best structure to organize it?
one solution is to create a base class for Class A which implements only I1, and make Class A derived implementing I2:
Class BaseA:I1
Class A: I2, BaseA
Do you know any smarter solution?
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You should only use a base class where you want the exact same implementation in all derived classes.
A an interface is a contract (no implementation unlike an abstract class) I don't really see the problem. This works just fine:
public interface I1
{
void A();
void B();
}
public interface I2
{
void A();
void B();
void C();
void D();
}
public class ClassA : I1, I2
{
public void A()
{ }
public void B()
{ }
public void C()
{ }
public void D()
{ }
}
If you want differing implementations of A and B depending on whether usin I1 or I2 then use explicit declaration:
public class ClassA2 : I1, I2
{
void I1.A()
{ }
void I2.A()
{ }
void I1.B()
{ }
void I2.B()
{ }
public void C()
{ }
public void D()
{ }
}
You will now need to cast the instance to either I1 or I2 to have access to methods A or B, but you can mix it up and provide the default implementation:
public class ClassA2 : I1, I2
{
public void A()
{
(this as I1).A();
}
public void B()
{
(this as I1).B();
}
void I1.A()
{ }
void I2.A()
{ }
void I1.B()
{ }
void I2.B()
{ }
public void C()
{ }
public void D()
{ }
}
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may be not clear my question:
I2 has "a" and "b" methods that are the same of I1
So I2:I1
But the class A not always is able to implement I2. It depend on the constructor used in A. If A is instantiated using a contructor, then A implement I2, otherwise only I1.
This is why I create a base class
So:
I2:I1
BaseA: I1
A:BaseA, I2
This is the herarchy, it works, but it looks a bit overkilling for the simple problem. I was only asking if there is a more elegant solution..
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Why not make I2 and abstract class so that when I2's methods are not implemented by ClassA the default empty implementation will work. here is some sample code:
Note: Replace I2 with A2 and ClassA and ClassA2 are two possible versions you could have for ClassA
public interface I1
{
void A();
void B();
}
public abstract class A2 : I1
{
public virtual void C()
{
}
public virtual void D()
{
}
#region I1 Members
public abstract void A();
public abstract void B();
#endregion
}
public class ClassA : A2
{
public override void A()
{
}
public override void B()
{
}
}
public class ClassA2 : A2
{
public override void A()
{
}
public override void B()
{
}
public override void C()
{
}
public override void D()
{
}
}
Every now and then say, "What the Elephant." "What the Elephant" gives you freedom. Freedom brings opportunity. Opportunity makes your future.
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Is there a plus in this design with respect my one?
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Strictly talking from a designs standpoint - Yes there is.
You see when we have an interface we are saying that we are defining a contract and all the classes implementing this interface should implement this contract i.e. methods. We cannot then say that we need to selectively implement the methods.
The abstract class says that, I am providing a default implementation and the derived class is free to have his own IF it needs to.
So in your case you needed some functions to be implemented selectively and some mandatory so following the design principle, I moved the mandatory ones in the contract i.e. the interface and the optional ones in abstract class. and in this particular case the default implementation of optional methods is to do nothing.
I hope i am able to convey my thoughts clearly. Do let me know if not. I am also open to counter arguments as they will only enhance my learning. (counter arguments == brainstorming) i.e. always beneficial 
Every now and then say, "What the Elephant." "What the Elephant" gives you freedom. Freedom brings opportunity. Opportunity makes your future.
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TheGermoz wrote: class A can implements I1 or I2 depending on how it is constructed
This is a dead giveaway for poor design. Inheritance hierarchies are telling you what operations you can do on an object, and you should be able to tell from the type of something what you can do with it. That is, an instance of A should always be treatable as an I2, or never.
What you almost certainly want to do is:
interface I1 {
void A();
void B();
}
interface I2 : I1 {
void C();
void D();
}
class A : I1 {
public virtual void A() {}
public virtual void B() {}
}
class A2 : A, I2 {
public void C() {}
public void D() {}
public override void A() {
base.A();
}
}
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yes this is my degign I propose, I was wandering if it is ok
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This is good. +5.
P.S. We might do away with the interface containing the optional functions as these are not a part of the contract. Also we can make class A as abstract to make sure no one is able to create it directly as its only purpose is to facilitate default implementation for optional functions.
I tried to do this design this way. I would love to hear your opinion on it:
http://www.codeproject.com/Messages/4429095/Re-Design-Question.aspx[^]
Every now and then say, "What the Elephant." "What the Elephant" gives you freedom. Freedom brings opportunity. Opportunity makes your future.
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Since we don't know what the interfaces or the class 'A' represent we can't be sure what the contracts needed are. But as the question has two interfaces in it, it seems likely that he needs both, and publicly instantiable classes that implement each.
Rahul Rajat Singh wrote: Also we can make class A as abstract to make sure no one is able to create it directly as its only purpose is to facilitate default implementation for optional functions.
I don't think that's true. The original question suggests that it is possible to construct an A which is fully functional but only supports the I1 operations, and that it's also possible to construct an A which additionally implements I2. That means you need a concrete class and a concrete subclass.
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Is there a reason why you are using interfaces? Too many .NET programmers make the mistake of thinking they need to use interfaces everywhere. Just like any other technology/construct/etc., you should only use interfaces when appropriate.
Is anybody using your class external to your app?
Based on the information you provided in your post, your design should be:
class A
{
virtual void a();
virtual void b();
}
class B : A
{
virtual void c();
virtual void d();
}
why over complicate? KISS.
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Yes really there is a reason, the example was a very simplify version of may real problem. Anyway I appreciate your answer
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Make interface I1 an abstract class instead (A1) or just create the class, whichever makes more sense, and inherit from A1 when you implement I2. Probably no reason to have the interface and the base class A1
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