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• Automated Java to Scala source code conversion?

  - by Alex R

  (Yes I know I can call Java code from Scala; but that is pointless; I want to DELETE the Java code, not keep it around and have to look at it and maintain it forever!) Are there any utilities out there to convert Java source to Scala source? I believe theoretically it should be possible to accomplish with minimal lossage. I have found this but it seems inactive, probably buggy/incomplete... http://sourceforge.net/projects/java2scala/ Any alternatives?

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• Organizing Eager Queries in an ObjectContext

  - by Nix

  I am messing around with Entity Framework 3.5 SP1 and I am trying to find a cleaner way to do the below. I have an EF model and I am adding some Eager Loaded entities and i want them all to reside in the "Eager" property in the context. We originally were just changing the entity set name, but it seems a lot cleaner to just use a property, and keep the entity set name in tact. Example: Context - EntityType - AnotherType - Eager (all of these would have .Includes to pull in all assoc. tables) - EntityType - AnotherType Currently I am using composition but I feel like there is an easier way to do what I want. namespace Entities{ public partial class TestObjectContext { EagerExtensions Eager { get;set;} public TestObjectContext(){ Eager = new EagerExtensions (this); } } public partial class EagerExtensions { TestObjectContext context; public EagerExtensions(TestObjectContext _context){ context = _context; } public IQueryable<TestEntity> TestEntity { get { return context.TestEntity .Include("TestEntityType") .Include("Test.Attached.AttachedType") .AsQueryable(); } } } } public class Tester{ public void ShowHowIWantIt(){ TestObjectContext context= new TestObjectContext(); var query = from a in context.Eager.TestEntity select a; } }

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• How many parameters in C# method are acceptable?

  - by Valentin Heinitz

  I am new to C# and have to maintain a C# Application. Now I'v found a method vaving 32 Parameters (not auto-generated code). From C/C++ I remember the rule of thumb "4 Parameters". It may be an old-fashioned rule rooting back to old 0x86 compilers, where 4 Parameters could be accomodated in registers (fast) or on stack otherwise. I am not concerning about performance, but I do have a feeling, that 32 parameters per functions are not easy to maintain even in C#. Or am I completly not up to date? What is the rule of thumb for C#? Thank you for any hint!

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• how to write a constructor...

  - by Nima

  is that correct to write a constructor like this? class A { A::A(const A& a) { .... } }; if yes, then is it correct to invoke it like this: A* other; ... A* instance = new A(*(other)); if not, what do you suggest? Thanks

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• Are these jobs for developer or designers or for client itself? for a web-site projects

  - by jitendra

  Spell checking grammar checking Descriptive alt text for big chart , graph images, technical images To write Table summary and caption Descriptive Link text Color Contrast checking Deciding in content what should be H2 ,H3, H4... and what should be <strong> or <span class="boldtext"> Meta Description and keywords for each pages Image compression To decide Filenames for images,PDf etc To decide Page's <title> for each page

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• Are these jobs for developer or designers or for client himself? for a web-site projects [closed]

  - by jitendra

  Are these jobs for developer or for designers or for client himself? for a web-site projects. Client is asking to do all things to XHTML CSS PHP coder.. Spell checking grammar checking Descriptive alt text for big chart , graph images, technical images To write Table summary and caption Descriptive Link text Color Contrast checking Deciding in content what should be H2 ,H3, H4... and what should be <strong> or <span class="boldtext"> Meta Description and keywords for each pages Image compression To decide Filenames for images,PDf etc To decide Page's <title> for each page

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• Need some clarification with Patterns (DAO x Gateway)

  - by Marcos Placona

  Me and my colleagues got into this discussion early this morning, and our opinions started to clash a bit, so I decided to get some impartial advice here. One of my colleagues reckons that the DAO should return an object (populated bean). I think it's completely fine when you're returning a recordset with only one line, but think it's overkill if you have to return 10 lines, and create 10 separate objects. I on the other see that the difference between DAO and Gateway pattern is that the gateway pattern will allow you to return a recordset to your business class, which will therefore deal with the recordset data and do whatever it needs to do. My questions here are: Which assumptions are correct? What should the return type be for a DAO (i.e. getContact() - for one record) Should getContacts() (for multiple records) even be on the DAO, if so, what's it's returntype? We seem to be having some sort of confusion about DAO and Gateway Patterns. Should they be used together? Thanks in advance

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• Events and references pattern

  - by serhio

  In a project I have the following relation between BO and GUI By e.g. G could represent a graphic with time lines, C a TimeLine curve, P - points of that curve and T the time that represents each point. Each GUI object is associated with the BO corresponding object. When T changes GUI P captures the Changed event and changes its location. So, when G should be modified, it modifies internally its objects and as result T changes, P moves and the GuiG visually changes, everything is OK. But there is an inconvenient of this architecture... BO should not be recreated, because this will breack the link between BO and GUIO. In particular, GUI P should always have the same reference of T. If in a business logic I do by e.g. P1.T = new T(this.T + 10) GUI_P1 will not move anymore, because it wait an event from the reference of former P1.T object, that does not belongs to P1 anymore. So the solution was to always modify the existing objects, not to recreate it. But here is an other inconvenient: performance. Say I have a ready newC object that should replace the older one. Instead of doing G1.C = newC I should do foreach T in foreach P in C replace with T from P from newC. Is there an other more optimal way to do it?

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• How to make some functions of a class as private for third level of inheritance.

  - by Shantanu Gupta

  I have created a class say A which has some functions defined as protected. Now Class B inherits A and class C inherits B. Class A has private default constructor and protected parameterized constructor. I want Class B to be able to access all the protected functions defined in Class A but class C can have access on some of the functions only not all the functions and class C is inheriting class B. How can I restrict access to some of the functions of Class A from Class C ? Class A { private A(){} protected A(int ){} protected calc(){} protected allow(){} } Class B : A {} // calc() and allow() should be accessible here CLass C:B { // calc() should not be accessible here but allow() should be accessible here. }

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• Database Table Schema and Aggregate Roots

  - by bretddog

  Hi, Applicaiton is single user, 1-tier(1 pc), database SqlCE. DataService layer will be (I think) : Repository returning domain objects and quering database with LinqToSql (dbml). There are obviously a lot more columns, this is simplified view. http://img573.imageshack.us/img573/3612/ss20110115171817w.png This is my first attempt of creating a 2 tables database. I think the table schema makes sense, but I need some reassurance or critics. Because the table relations looks quite scary to be honest. I'm hoping you could; Look at the table schema and respond if there are clear signs of troubles or errors that you spot right away.. And if you have time, Look at Program Summary/Questions, and see if the table layout makes makes sense to those points. Please be brutal, I will try to defend :) Program summary: a) A set of categories, each having a set of strategies (1:m) b) Each day a number of items will be produced. And each strategy MAY reference it. (So there can be 50 items, and a strategy may reference 23 of them) c) An item can be referenced by more than one strategy. So I think it's an m:m relation. d) Status values will be logged at fixed time-fractions through the day, for: - .... each Strategy.....each StrategyItem....each item e) An action on an item may be executed by a strategy that reference it. - This is logged as ItemAction (Could have called it StrategyItemAction) User Requsts b) - e) described the main activity mode of the program. To work with only today's DayLog , for each category. 2nd priority activity is retrieval of history, which typically will be From all categories, from day x to day y; Get all StrategyDailyLog. Questions First, does the overall layout look sound? I'm worried to see that there are so many relationships in all directions, connecting everything. Is this normal, or does it look like trouble? StrategyItem is made to represent an m:m relationship. Is it correct as I noted 1:m / 1:1 (marked red) ? StrategyItemTimeLog and ItemTimeLog; Logs values that both need to be retrieved together, when retreiving a StrategyItem. Reason I separated is that the first one is strategy-specific, and several strategies can reference same item. So I thought not to duplicate those values that are not dependent no strategy, but only on the item. Hence I also dragged out the LogTime, as it seems to be the only parameter to unite the logs. But this all looks quite disturbing with those 3 tables. Does it make sense at all? Or you have suggestion? Pink circles shows my vague attempt of Aggregate Root Paths. I've been thinking in terms of "what entity is responsible for delete". Though I'm unsure about the actual root. I think it's Category. Does it make sense related to User Requests described above?

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• Meta Search Engine Architecture

  - by Loki

  The question wasn't clear enough, I think; here's an updated straight to the point question: What are the common architectures used in building a meta search engine and is there any libraries available to build that type of search engine? I'm looking at building an "enterprise" type of search engine where the indexed data could be coming from proprietary (like Autonomy or a Google Box) or public search engines (like Google Web or Yahoo Web).

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• Creating an object relational schema from a Class diagram

  - by Caylem

  Hi Ladies and Gents. I'd like some help converting the following UML diagram: UML Diagram The diagram shows 4 classes and is related to a Loyalty card scheme for an imaginary supermarket. I'd like to create an object relational data base schema from it for use with Oracle 10g/11g. Not sure where to begin, if somebody could give me a head start that would be great. Looking for actually starting the schema, show abstraction, constraints, types(subtypes, supertypes) methods and functions. Note: I'm not looking for anyone to make any comments regarding the actual classes and whether changes should be made to the Diagram, just the schema. Thanks

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• How to model a mutually exclusive relationship in sql server

  - by littlechris

  Hi, I have to add functionality to an existing application and I've run into a data situation that I'm not sure how to model. I am being restricted to the creation of new tables and code. If I need to alter the existing structure I think my client may reject the proposal..although if its the only way to get it right this is what I will have to do. I have an Item table that can me link to any number of tables, and these tables may increase over time. The Item can only me linked to one other table, but the record in the other table may have many items linked to it. Examples of the tables/entities being linked to are "Person", "Vehicle", "Building", "Office". These are all separate tables. Example of Items are "Pen", "Stapler", "Cushion", "Tyre", "A4 Paper", "Plastic Bag", "Poster", "Decoration" For instance a "Poster" may be allocated to a "Person" or "Office" or "Building". In the future if they add a "Conference Room" table it may also be added to that. My intital thoughts are: Item { ID, Name } LinkedItem { ItemID, LinkedToTableName, LinkedToID } The LinkedToTableName field will then allow me to identify the correct table to link to in my code. I'm not overly happy with this solution, but I can't quite think of anything else. Please help! :) Thanks!

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• smallest mysql type that accomodates single decimal

  - by donpal

  Database newbie here. I'm setting up a mysql table. One of the fields will accept a value in increment of a 0.5. e.g. 0.5, 1.0, 1.5, 2.0, .... 200.5, etc. I've tried int but it doesn't capture the decimals. `value` int(10), What would be the smallest type that can accommodate this value, considering it's only a single decimal. I also was considering that because the decimal will always be 0.5 if at all, I could store it in a separate boolean field? So I would have 2 fields instead. Is this a stupid or somewhat over complicated idea? I don't know if it really saves me any memory, and it might get slower now that I'm accessing 2 fields instead of 1 `value` int(10), `half` bool, //or something similar to boolean What are your suggestions guys? Is the first option better, and what's the smallest data type in that case that would get me the 0.5?

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• In a PHP project, how do you organize and access your helper objects?

  - by Pekka

  How do you organize and manage your helper objects like the database engine, user notification, error handling and so on in a PHP based, object oriented project? Say I have a large PHP CMS. The CMS is organized in various classes. A few examples: the database object user management an API to create/modify/delete items a messaging object to display messages to the end user a context handler that takes you to the right page a navigation bar class that shows buttons a logging object possibly, custom error handling etc. I am dealing with the eternal question, how to best make these objects accessible to each part of the system that needs it. my first apporach, many years ago was to have a $application global that contained initialized instances of these classes. global $application; $application->messageHandler->addMessage("Item successfully inserted"); I then changed over to the Singleton pattern and a factory function: $mh =&factory("messageHandler"); $mh->addMessage("Item successfully inserted"); but I'm not happy with that either. Unit tests and encapsulation become more and more important to me, and in my understanding the logic behind globals/singletons destroys the basic idea of OOP. Then there is of course the possibility of giving each object a number of pointers to the helper objects it needs, probably the very cleanest, resource-saving and testing-friendly way but I have doubts about the maintainability of this in the long run. Most PHP frameworks I have looked into use either the singleton pattern, or functions that access the initialized objects. Both fine approaches, but as I said I'm happy with neither. I would like to broaden my horizon on what is possible here and what others have done. I am looking for examples, additional ideas and pointers towards resources that discuss this from a long-term, real-world perspective. Also, I'm interested to hear about specialized, niche or plain weird approaches to the issue. Bounty I am following the popular vote in awarding the bounty, the answer which is probably also going to give me the most. Thank you for all your answers!

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• Should I use custom exceptions to control the flow of application?

  - by bonefisher

  Is it a good practise to use custom business exceptions (e.g. BusinessRuleViolationException) to control the flow of user-errors/user-incorrect-inputs??? The classic approach: I have a web service, where I have 2 methods, one is the 'checker' (UsernameAlreadyExists()) and the other one is 'creator' (CreateUsername())... So if I want to create a username, I have to do 2 roundtrips to webservice, 1.check, 2.if check is OK, create. What about using UsernameAlreadyExistsException? So I call only the 2. web service method (CrateUsername()), which contains the check and if not successfull, it throws the UsernameAlreadyExistsException. So the end goal is to have only one round trip to web service and the checking can be contained also in other web service methods (so I avoid calling the UsernameAlreadyExists() all the times..). Furthermore I can use this kind of business error handling with other web service calls completely avoiding the checking prior the call.

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• Postgre database ignoring created index ?!

  - by drasto

  I have an Postgre database and a table called my_table. There are 4 columns in that table (id, column1, column2, column3). The id column is primary key, there are no other constrains or indexes on columns. The table has about 200000 rows. I want to print out all rows which has value of column column2 equal(case insensitive) to 'value12'. I use this: SELECT * FROM my_table WHERE column2 = lower('value12') here is the execution plan for this statement(result of set enable_seqscan=on; EXPLAIN SELECT * FROM my_table WHERE column2 = lower('value12')): Seq Scan on my_table (cost=0.00..4676.00 rows=10000 width=55) Filter: ((column2)::text = 'value12'::text) I consider this to be to slow so I create an index on column column2 for better prerformance of searches: CREATE INDEX my_index ON my_table (lower(column2)) Now I ran the same select: SELECT * FROM my_table WHERE column2 = lower('value12') and I expect it to be much faster because it can use index. However it is not faster, it is as slow as before. So I check the execution plan and it is the same as before(see above). So it still uses sequential scen and it ignores the index! Where is the problem ?

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• Question about best practices and Macros from the book 'C++ Coding Standards'

  - by Victor T.

  From Herb Sutter and Andrei Alexandrescu's 'C++ Coding Standards', Item 16: Avoid Macros under Exceptions for this guideline they wrote: For conditional compilation (e.g., system-dependent parts), avoid littering your code with #ifdefs. Instead, prefer to organize code such that the use of macros drives alternative implementations of one common interface, and then use the interface throughout. I'm having trouble understanding exactly what they mean by this. How can you drive alternate implementations without the use of #ifdef conditional compile macro directives? Can someone provide an example to help illustrate what's being proposed by the above paragraph? Thanks

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• Normalizing Item Names & Synonyms

  - by RabidFire

  Consider an e-commerce application with multiple stores. Each store owner can edit the item catalog of his store. My current database schema is as follows: item_names: id | name | description | picture | common(BOOL) items: id | item_name_id | picture | price | description | picture item_synonyms: id | item_name_id | name | error(BOOL) Notes: error indicates a wrong spelling (eg. "Ericson"). description and picture of the item_names table are "globals" that can optionally be overridden by "local" description and picture fields of the items table (in case the store owner wants to supply a different picture for an item). common helps separate unique item names ("Jimmy Joe's Cheese Pizza" from "Cheese Pizza") I think the bright side of this schema is: Optimized searching & Handling Synonyms: I can query the item_names & item_synonyms tables using name LIKE %QUERY% and obtain the list of item_name_ids that need to be joined with the items table. (Examples of synonyms: "Sony Ericsson", "Sony Ericson", "X10", "X 10") Autocompletion: Again, a simple query to the item_names table. I can avoid the usage of DISTINCT and it minimizes number of variations ("Sony Ericsson Xperia™ X10", "Sony Ericsson - Xperia X10", "Xperia X10, Sony Ericsson") The down side would be: Overhead: When inserting an item, I query item_names to see if this name already exists. If not, I create a new entry. When deleting an item, I count the number of entries with the same name. If this is the only item with that name, I delete the entry from the item_names table (just to keep things clean; accounts for possible erroneous submissions). And updating is the combination of both. Weird Item Names: Store owners sometimes use sentences like "Harry Potter 1, 2 Books + CDs + Magic Hat". There's something off about having so much overhead to accommodate cases like this. This would perhaps be the prime reason I'm tempted to go for a schema like this: items: id | name | picture | price | description | picture (... with item_names and item_synonyms as utility tables that I could query) Is there a better schema you would suggested? Should item names be normalized for autocomplete? Is this probably what Facebook does for "School", "City" entries? Is the first schema or the second better/optimal for search? Thanks in advance! References: (1) Is normalizing a person's name going too far?, (2) Avoiding DISTINCT

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• How can I handle dynamic calculated attributes in a model in Django?

  - by bullfish

  In Django I calculate the breadcrumb (a list of fathers) for an geographical object. Since it is not going to change very often, I am thinking of pre calculating it once the object is saved or initialized. 1.) What would be better? Which solution would have a better performance? To calculate it at _init_ or to calculate it when the object is saved (the object takes about 500-2000 characters in the DB)? 2.) I tried to overwrite the _init_ or save() methods but I don't know how to use attributes of the just saved object. Accessing *args, **kwargs did not work. How can I access them? Do I have to save, access the father and then save again? 3.) If I decide to save the breadcrumb. Whats the best way to do it? I used http://www.djangosnippets.org/snippets/1694/ and have crumb = PickledObjectField(). Thats the method to calculate the attribute crumb() def _breadcrumb(self): breadcrumb = [ ] x = self while True: x = x.father try: if hasattr(x, 'country'): breadcrumb.append(x.country) elif hasattr(x, 'region'): breadcrumb.append(x.region) elif hasattr(x, 'city'): breadcrumb.append(x.city) else: break except: break breadcrumb.reverse() return breadcrumb Thats my save-Method: def save(self,*args, **kwargs): # how can I access the father ob the object? father = self.father # does obviously not work father = kwargs['father'] # does not work either # the breadcrumb gets calculated here self.crumb = self._breadcrumb(father) super(GeoObject, self).save(*args,**kwargs) Please help me out. I am working on this for days now. Thank you.

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• Is there a programming language that performs currying when named parameters are omitted?

  - by Adam Gent

  Many functional programming languages have support for curried parameters. To support currying functions the parameters to the function are essentially a tuple where the last parameter can be omitted making a new function requiring a smaller tuple. I'm thinking of designing a language that always uses records (aka named parameters) for function parameters. Thus simple math functions in my make believe language would be: add { left : num, right : num } = ... minus { left : num, right : num } = .. You can pass in any record to those functions so long as they have those two named parameters (they can have more just "left" and "right"). If they have only one of the named parameter it creates a new function: minus5 :: { left : num } -> num minus5 = minus { right : 5 } I borrow some of haskell's notation for above. Has any one seen a language that does this?

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• Is it possible to create a domain model for legacy code without refactoring?

  - by plaureano

  I currently have a client that wants me to 'abstract' out a domain model from the existing code but they specifically said that I shouldn't refactor the existing code itself. My question is 1) whether or not this is advisable and 2) what techniques would you apply in this scenario if you can't refactor the code yet they expect you to come up with a model for it? (EDIT: I can't quite put my finger on it, but somehow, not being able to refactor in this case just feels wrong. Has anyone else run into this type of scenario?)

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• what happens to running/blocked runnables when executorservice is shutdown()

  - by prmatta

  I posted a question about a thread pattern today, and almost everyone suggested that I look into the ExecutorService. While I was looking into the ExecutorService, I think I am missing something. What happens if the service has a running or blocked threads, and someone calls ExecutorService.shutdown(). What happens to threads that are running or blocked? Does the ExecutorService wait for those threads to complete before it terminates? The reason I ask this is because a long time ago when I used to dabble in Java, they deprecated Thread.stop(), and I remember the right way of stopping a thread was to use sempahores and extend Thread when necessary: public void run () { while (!this.exit) { try { block(); //do something } catch (InterruptedException ie) { } } } public void stop () { this.exit = true; if (this.thread != null) { this.thread.interrupt(); this.thread = null; } } How does ExecutorService handle running threads?

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• What is there so useful in the Decorator Pattern? My example doesn't work

  - by Green

  The book says: The decorator pattern can be used to extend (decorate) the functionality of a certain object I have a rabbit animal. And I want my rabbit to have, for example, reptile skin. Just want to decorate a common rabbit with reptile skin. I have the code. First I have abstract class Animal with everythig that is common to any animal: abstract class Animal { abstract public function setSleep($hours); abstract public function setEat($food); abstract public function getSkinType(); /* and more methods which for sure will be implemented in any concrete animal */ } I create class for my rabbit: class Rabbit extends Animal { private $rest; private $stomach; private $skinType = "hair"; public function setSleep($hours) { $this->rest = $hours; } public function setFood($food) { $this->stomach = $food; } public function getSkinType() { return $this->$skinType; } } Up to now everything is OK. Then I create abstract AnimalDecorator class which extends Animal: abstract class AnimalDecorator extends Animal { protected $animal; public function __construct(Animal $animal) { $this->animal = $animal; } } And here the problem comes. Pay attention that AnimalDecorator also gets all the abstract methods from the Animal class (in this example just two but in real can have many more). Then I create concrete ReptileSkinDecorator class which extends AnimalDecorator. It also has those the same two abstract methods from Animal: class ReptileSkinDecorator extends AnimalDecorator { public function getSkinColor() { $skin = $this->animal->getSkinType(); $skin = "reptile"; return $skin; } } And finaly I want to decorate my rabbit with reptile skin: $reptileSkinRabbit = ReptileSkinDecorator(new Rabbit()); But I can't do this because I have two abstract methods in ReptileSkinDecorator class. They are: abstract public function setSleep($hours); abstract public function setEat($food); So, instead of just re-decorating only skin I also have to re-decorate setSleep() and setEat(); methods. But I don't need to. In all the book examples there is always ONLY ONE abstract method in Animal class. And of course it works then. But here I just made very simple real life example and tried to use the Decorator pattern and it doesn't work without implementing those abstract methods in ReptileSkinDecorator class. It means that if I want to use my example I have to create a brand new rabbit and implement for it its own setSleep() and setEat() methods. OK, let it be. But then this brand new rabbit has the instance of commont Rabbit I passed to ReptileSkinDecorator: $reptileSkinRabbit = ReptileSkinDecorator(new Rabbit()); I have one common rabbit instance with its own methods in the reptileSkinRabbit instance which in its turn has its own reptileSkinRabbit methods. I have rabbit in rabbit. But I think I don't have to have such possibility. I don't understand the Decarator pattern right way. Kindly ask you to point on any mistakes in my example, in my understanding of this pattern. Thank you.

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• Autmatically create table on MySQL server based on date?

  - by Anthony

  Is there an equivalent to cron for MySQL? I have a PHP script that queries a table based on the month and year, like: SELECT * FROM data_2010_1 What I have been doing until now is, every time the script executes it does a query for the table, and if it exists, does the work, if it doesn't it creates the table. I was wondering if I can just set something up on the MySQL server itself that will create the table (based on a default table) at the stroke of midnight on the first of the month. Update Based on the comments I've gotten, I'm thinking this isn't the best way to achieve my goal. So here's two more questions: If I have a table with thousands of rows added monthly, is this potentially a drag on resources? If so, what is the best way to partition this table, since the above is verboten? What are the potential problems with my home-grown method I originally thought up?

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