How do I decide for class responsibilities?
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How do I decide what types to make and what responsibilities to give them, given a design concept? Should I base myself on user stories/functional requirements in order to decide which responsibilities my classes need? It's not easy to adhere to the SOLID principle. For example I have this.. 'make a blog' assignment. I wrote down one of those functional requirements: "a blog entry has to have a title and a body". Does that mean I have to write a class Post with members Body and Title? Should a Post (BlogEntry) class only have a body and the title is supposed to be the responsibility of another class? Kind of confusing. There must be a set of rules that tell programmers how to decide on which objects to make and what responsibilities and implementation to give them. Any ideas on this? Thanks
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How do I decide what types to make and what responsibilities to give them, given a design concept? Should I base myself on user stories/functional requirements in order to decide which responsibilities my classes need? It's not easy to adhere to the SOLID principle. For example I have this.. 'make a blog' assignment. I wrote down one of those functional requirements: "a blog entry has to have a title and a body". Does that mean I have to write a class Post with members Body and Title? Should a Post (BlogEntry) class only have a body and the title is supposed to be the responsibility of another class? Kind of confusing. There must be a set of rules that tell programmers how to decide on which objects to make and what responsibilities and implementation to give them. Any ideas on this? Thanks
This is something that gets easier the more you practice. Start by writing down in PROPER prose what the software will do. Now take all the nouns out, they are your candidate classes. Firstly find the items that are synonyms - blog, post, posting and entry will most likely be used to reference the same thing. Then have a look at what is left and if the items actually perform anything or if they just record a state. If all they are recording is state, then they are probably attributes rather than classes. In your case, I think you'll find the body and title are probably just attributes. However, there is not a single way to do these things and it is an experience thing that will tell you which is best. Alas there is not really enough here for me to give you a fuller answer.
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
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This is something that gets easier the more you practice. Start by writing down in PROPER prose what the software will do. Now take all the nouns out, they are your candidate classes. Firstly find the items that are synonyms - blog, post, posting and entry will most likely be used to reference the same thing. Then have a look at what is left and if the items actually perform anything or if they just record a state. If all they are recording is state, then they are probably attributes rather than classes. In your case, I think you'll find the body and title are probably just attributes. However, there is not a single way to do these things and it is an experience thing that will tell you which is best. Alas there is not really enough here for me to give you a fuller answer.
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
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Hmm.. I learned that the method of taking out nouns and looking at verbs is incorrect. It is more abstract.
So your 1 semester class trumps my 25 years of experience, well done. I said it is a starting point. With EXPERIENCE you don't need to bother and you can see the classes inherent in a system easily, but that comes with practice. Lots and lots of practice.
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
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So your 1 semester class trumps my 25 years of experience, well done. I said it is a starting point. With EXPERIENCE you don't need to bother and you can see the classes inherent in a system easily, but that comes with practice. Lots and lots of practice.
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
Excuse me? I come from a university with one of the highest reputations there are. We program and work the qualitative way. This isn't one semester. It's my graduate year. I'm actually going to be an Application Developer. There's only so far you can get with 'practice' and 'experience'. Fundamental concepts and methods are far more important. That's why the top engineers get higher ranked without doing the work. Didn't you ever learn that? The tons of math and logic theory I had to process before I came to this point. The years of lectures on Software Engineering. Never underestimate the importance of scholar theory.
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Excuse me? I come from a university with one of the highest reputations there are. We program and work the qualitative way. This isn't one semester. It's my graduate year. I'm actually going to be an Application Developer. There's only so far you can get with 'practice' and 'experience'. Fundamental concepts and methods are far more important. That's why the top engineers get higher ranked without doing the work. Didn't you ever learn that? The tons of math and logic theory I had to process before I came to this point. The years of lectures on Software Engineering. Never underestimate the importance of scholar theory.
Dear boy, I have been there already. FYI, I recently did another degree course - exactly to get an update on the academic theory - and noun/verbal extraction is still a very valid and useful exercise. When, or if, you work professionally, you will understand that there is so much within the problem domain that impacts how classes are decided upon. Experience is the dog's doo-dahs in deciding how to break down a problem domain to find candidate classes.
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
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Excuse me? I come from a university with one of the highest reputations there are. We program and work the qualitative way. This isn't one semester. It's my graduate year. I'm actually going to be an Application Developer. There's only so far you can get with 'practice' and 'experience'. Fundamental concepts and methods are far more important. That's why the top engineers get higher ranked without doing the work. Didn't you ever learn that? The tons of math and logic theory I had to process before I came to this point. The years of lectures on Software Engineering. Never underestimate the importance of scholar theory.
CsTreval wrote:
I come from a university with one of the highest reputations there are.
Soon to be lowest.
CsTreval wrote:
I'm actually going to be an Application Developer.
With this attitude you are bound to go far.
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Excuse me? I come from a university with one of the highest reputations there are. We program and work the qualitative way. This isn't one semester. It's my graduate year. I'm actually going to be an Application Developer. There's only so far you can get with 'practice' and 'experience'. Fundamental concepts and methods are far more important. That's why the top engineers get higher ranked without doing the work. Didn't you ever learn that? The tons of math and logic theory I had to process before I came to this point. The years of lectures on Software Engineering. Never underestimate the importance of scholar theory.
My graduate university is ranked among the lowest in England, even they taught us that even with experience there is always more to learn. Education is great but never tie yourself to it, what works in theory doesn't always apply to every situation. In industry experience is worth more atleast until you actually have had a few jobs. Software development is the one field where a specific degree doesn't necessarily make you better than Joe Bloggs who self-taught. Also experience > actual software developed > education as far as I can see Also lose the idea that top people get paid to do practically nothing you will find that even some CEOs work over 9 hours a day, design and planning may be what they (top engineers) actually get paid for but that still involves thinking and much of that comes as the result of experience.
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My graduate university is ranked among the lowest in England, even they taught us that even with experience there is always more to learn. Education is great but never tie yourself to it, what works in theory doesn't always apply to every situation. In industry experience is worth more atleast until you actually have had a few jobs. Software development is the one field where a specific degree doesn't necessarily make you better than Joe Bloggs who self-taught. Also experience > actual software developed > education as far as I can see Also lose the idea that top people get paid to do practically nothing you will find that even some CEOs work over 9 hours a day, design and planning may be what they (top engineers) actually get paid for but that still involves thinking and much of that comes as the result of experience.
Right. At your university they never taught you in the advanced English class about the Dilbert principle? This happens in real life too, you know? Hence the principle. I know some people who get paid very highly and I chat with them for about 50% of the time I'm taking lectures. What does this imply? Well, it implies that they are sitting on their chair all day being lazy and getting paid huge salaries (because I know his function). It used to be that the really hard working and intelligent people were bumped up to manager. Now it's the other way around. If you really believe that hard working smart people get the better salaries, you're wrong. I've experienced nothing like it in the real world. I've worked before as well. I've been programming on a 3 month contract in a company my university suggested. The programmers were just absolutely horrible and cynical people. They were also not very bright. I knew more about programming and computers than they did. Anyway not to drift off the point here. Experience certainly may help in the IT industry of today, but if it wasn't for my university's high reputation (because they have excellent courses and professors) I wouldn't even have had the slightest chance to function as a temporary programmer in a company. I tried before. You have no idea how many 'no' answers I got. Meanwhile, a top paid programmer I know who works for one of the best software development companies can only type with two fingers and can't even do a copy paste in Excel! How fair is that?! Yes, what a world. With hard work you get somewhere.. please.
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Right. At your university they never taught you in the advanced English class about the Dilbert principle? This happens in real life too, you know? Hence the principle. I know some people who get paid very highly and I chat with them for about 50% of the time I'm taking lectures. What does this imply? Well, it implies that they are sitting on their chair all day being lazy and getting paid huge salaries (because I know his function). It used to be that the really hard working and intelligent people were bumped up to manager. Now it's the other way around. If you really believe that hard working smart people get the better salaries, you're wrong. I've experienced nothing like it in the real world. I've worked before as well. I've been programming on a 3 month contract in a company my university suggested. The programmers were just absolutely horrible and cynical people. They were also not very bright. I knew more about programming and computers than they did. Anyway not to drift off the point here. Experience certainly may help in the IT industry of today, but if it wasn't for my university's high reputation (because they have excellent courses and professors) I wouldn't even have had the slightest chance to function as a temporary programmer in a company. I tried before. You have no idea how many 'no' answers I got. Meanwhile, a top paid programmer I know who works for one of the best software development companies can only type with two fingers and can't even do a copy paste in Excel! How fair is that?! Yes, what a world. With hard work you get somewhere.. please.
Wow. That was a bunch of useless, meaningless crap. Did they also teach you, in your exalted university, that your final year is where you demonstrate that you can apply the techniques and information you've been fed over the last 3 years? If you're asking this question now, it seems that you're in a bit of trouble.
A guide to posting questions on CodeProject[^]
Dave Kreskowiak -
How do I decide what types to make and what responsibilities to give them, given a design concept? Should I base myself on user stories/functional requirements in order to decide which responsibilities my classes need? It's not easy to adhere to the SOLID principle. For example I have this.. 'make a blog' assignment. I wrote down one of those functional requirements: "a blog entry has to have a title and a body". Does that mean I have to write a class Post with members Body and Title? Should a Post (BlogEntry) class only have a body and the title is supposed to be the responsibility of another class? Kind of confusing. There must be a set of rules that tell programmers how to decide on which objects to make and what responsibilities and implementation to give them. Any ideas on this? Thanks
It is confusing if you concentrate on one item to the exclusion of all else. Take your example; you have a statement that "a blog entry has to have a title and a body". Okay, I can see where you are going with that, but you're now wondering whether or not you violate SOLID to have a body element AND a title element. This is designing in isolation. You need to consider the other requirements to see what effect they have. For instance, suppose you have a requirement that states that a title must have more than 20 characters and less than 150 characters. Does this mean that you need to create a separate Title class which encapsulates the rules, or do you make it part of the BlogEntry class? Well, that depends - you might want to create a separate validation engine which is responsible for enforcing the rules, in which case you would probably just use attributes on your BlogEntry properties, so the mechanism for defining HOW to validate the properties is external, but the rules for each element are attached (this is a common technique). Then you need to consider where your rules are applied. Do you do everything in your UI, or do you abstract to a business rules class? Is your BlogEntry class actually a model instead? Should you use MVC? The thing I'm trying to get at here is that there is no "one size fits all" solution. As others have said, it's experience, but it is also a case that your start and end point has to be "what do I need to put in to satisfy the requirements?" By all means, consider the use cases - a well architected use case should be a vital part of developing your application because it should tell you how the user will actually use your application. Beyond that, adhering to SOLID is a mix of experience and common sense, and you shouldn't slavishly adhere to something just because someone else has written about how good it is.
*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington
"Mind bleach! Send me mind bleach!" - Nagy Vilmos
CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier
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It is confusing if you concentrate on one item to the exclusion of all else. Take your example; you have a statement that "a blog entry has to have a title and a body". Okay, I can see where you are going with that, but you're now wondering whether or not you violate SOLID to have a body element AND a title element. This is designing in isolation. You need to consider the other requirements to see what effect they have. For instance, suppose you have a requirement that states that a title must have more than 20 characters and less than 150 characters. Does this mean that you need to create a separate Title class which encapsulates the rules, or do you make it part of the BlogEntry class? Well, that depends - you might want to create a separate validation engine which is responsible for enforcing the rules, in which case you would probably just use attributes on your BlogEntry properties, so the mechanism for defining HOW to validate the properties is external, but the rules for each element are attached (this is a common technique). Then you need to consider where your rules are applied. Do you do everything in your UI, or do you abstract to a business rules class? Is your BlogEntry class actually a model instead? Should you use MVC? The thing I'm trying to get at here is that there is no "one size fits all" solution. As others have said, it's experience, but it is also a case that your start and end point has to be "what do I need to put in to satisfy the requirements?" By all means, consider the use cases - a well architected use case should be a vital part of developing your application because it should tell you how the user will actually use your application. Beyond that, adhering to SOLID is a mix of experience and common sense, and you shouldn't slavishly adhere to something just because someone else has written about how good it is.
*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington
"Mind bleach! Send me mind bleach!" - Nagy Vilmos
CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier
Intelligence without being a third year undergraduate! How the fock did you do that?
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
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Right. At your university they never taught you in the advanced English class about the Dilbert principle? This happens in real life too, you know? Hence the principle. I know some people who get paid very highly and I chat with them for about 50% of the time I'm taking lectures. What does this imply? Well, it implies that they are sitting on their chair all day being lazy and getting paid huge salaries (because I know his function). It used to be that the really hard working and intelligent people were bumped up to manager. Now it's the other way around. If you really believe that hard working smart people get the better salaries, you're wrong. I've experienced nothing like it in the real world. I've worked before as well. I've been programming on a 3 month contract in a company my university suggested. The programmers were just absolutely horrible and cynical people. They were also not very bright. I knew more about programming and computers than they did. Anyway not to drift off the point here. Experience certainly may help in the IT industry of today, but if it wasn't for my university's high reputation (because they have excellent courses and professors) I wouldn't even have had the slightest chance to function as a temporary programmer in a company. I tried before. You have no idea how many 'no' answers I got. Meanwhile, a top paid programmer I know who works for one of the best software development companies can only type with two fingers and can't even do a copy paste in Excel! How fair is that?! Yes, what a world. With hard work you get somewhere.. please.
Did your super duper university not teach you what a paragraph is? Legibility. Learn the word and learn it quickly!
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
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Intelligence without being a third year undergraduate! How the fock did you do that?
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
I probably knicked it from someone clever. And I'm someone who hasn't got a computer degree - largely self taught. I don't think it's done me any harm.
*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington
"Mind bleach! Send me mind bleach!" - Nagy Vilmos
CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier
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CsTreval wrote:
I come from a university with one of the highest reputations there are.
Soon to be lowest.
CsTreval wrote:
I'm actually going to be an Application Developer.
With this attitude you are bound to go far.
Undergraduates are so sweet when they think they know things.
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
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I probably knicked it from someone clever. And I'm someone who hasn't got a computer degree - largely self taught. I don't think it's done me any harm.
*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington
"Mind bleach! Send me mind bleach!" - Nagy Vilmos
CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier
I got my 'putin' degree only last year - after 25+ years - to find out what's new. Very little is the answer.
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
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I got my 'putin' degree only last year - after 25+ years - to find out what's new. Very little is the answer.
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
I believe most of it is just fancy names for what we were doing anyway.
*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington
"Mind bleach! Send me mind bleach!" - Nagy Vilmos
CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier
-
Did your super duper university not teach you what a paragraph is? Legibility. Learn the word and learn it quickly!
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
He didn't actually say what the University's reputation was for, just that it was the highest.
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I believe most of it is just fancy names for what we were doing anyway.
*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington
"Mind bleach! Send me mind bleach!" - Nagy Vilmos
CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier
The one thing I found fascinating was Systems Theory[^]. It has nothing to do what you think and is a complete mind fock until you get the little light come on...
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett
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He didn't actually say what the University's reputation was for, just that it was the highest.
Top for arrests? Absenteeism? We may never know... :-D
Panic, Chaos, Destruction. My work here is done. Drink. Get drunk. Fall over - P O'H OK, I will win to day or my name isn't Ethel Crudacre! - DD Ethel Crudacre I cannot live by bread alone. Bacon and ketchup are needed as well. - Trollslayer Have a bit more patience with newbies. Of course some of them act dumb - they're often *students*, for heaven's sake - Terry Pratchett