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  • How to fine tune FluentNHibernate's auto mapper?

    - by Venemo
    Okay, so yesterday I managed to get the latest trunk builds of NHibernate and FluentNHibernate to work with my latest little project. (I'm working on a bug tracking application.) I created a nice data access layer using the Repository pattern. I decided that my entities are nothing special, and also that with the current maturity of ORMs, I don't want to hand-craft the database. So, I chose to use FluentNHibernate's auto mapping feature with NHibernate's "hbm2ddl.auto" property set to "create". It really works like a charm. I put the NHibernate configuration in my app domain's config file, set it up, and started playing with it. (For the time being, I created some unit tests only.) It created all tables in the database, and everything I need for it. It even mapped my many-to-many relationships correctly. However, there are a few small glitches: All of the columns created in the DB allow null. I understand that it can't predict which properties should allow null and which shouldn't, but at least I'd like to tell it that it should allow null only for those types for which null makes sense in .NET (eg. non-nullable value types shouldn't allow null). All of the nvarchar and varbinary columns it created, have a default length of 255. I would prefer to have them on max instead of that. Is there a way to tell the auto mapper about the two simple rules above? If the answer is no, will it work correctly if I modify the tables it created? (So, if I set some columns not to allow null, and change the allowed length for some other, will it correctly work with them?) EDIT: I managed to achieve the above by using Fluent NHibernate's convention API. Thanks to everyone who helped! However, there is one more thing: after checking out the convention API, I really would like my IDs to be calld "ID", not "Id", but it seems to me that the PrimaryKey.Name.Is(x => "ID") is not working at all. If I add it to the conventions collection and rewrite my entities' properties to "ID" instead of "Id", it throws an exception that there is no primary key mapped. Any thoughts on this?

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  • Myself throwing NullReferenceException... needs help

    - by Amit Ranjan
    I know it might be a weird question and its Title too, but i need your help. I am a .net dev , working on platform for the last 1.5 years. I am bit confused on the term usually we say " A Good Programmer ". I dont know ,what are the qualities of a good programmer ? Is the guy who writes a bug free code? or Can develop applications solely? or blah blah blah...lots of points. I dont know... But as far i am concerned , I know I am not a good programmer, still in learning phase an needs a lot to learn in coming days. So you guys are requested to please help me with this two problems of mine My first problem is regarding the proper Error Handling, which is a most debatable aspect of programming. We all know we use ` try { } catch { } finally { } ` in our code to manage exception. But even if I use try { } catch(exception ex) { throw ex } finally { } , different guys have different views. I still dont know the good way to handle errors. I can write code, use try-catch but still i feel I lacks something. When I saw the codes generated by .net fx tools even they uses throw ex or `throw new Exception("this is my exception")`.. I am just wondering what will be the best way to achieve the above. All means the same thing but why we avoid something. If it has some demerits then it must be made obselete.Anyways I still dont have one [how to handle errors efficiently?]. I generally follow the try-catch(execoption ex){throw ex}, and usually got stucked in debates with leads why you follow this why not that... 2.Converting your entire code blocks in modules using Design patterns of some OOPs concepts. How do you guys decide what architeture or pattern will be the best for my upcoming application based on its working, flow etc. I need to know what you guys can see that I can't. Since I know , I dont have that much experience but I can say, with my experience that experience doesnot comes either from degree/certificates or success you made instead it cames from failures you faced or got stucking situations. Pleas help me out.

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  • Emails sent using Flex app are delayed

    - by user363825
    I'm currently building an application in Flex that utilizes SMTP Mailer to automatically send out emails to the user when a particular condition is satisfied. The application checks this condition every 30 seconds. The condition is satisfied based on new records being returned from a database table. The problem is as follows: When the condition is first satisfied, the email is delivered to the user with no issues. The second time the condition is satisfied, the email is not delivered. In the smtp logs, the delivery attempt appears to get hung up on the following line: 354 Start mail input; end with <CRLF>.<CRLF> No error codes are present in the smtp logs, but I do trace the following event from the SMTP Mailer class: [Event type="mailError" bubbles=false cancelable=false eventPhase=2] When the condition is satisfied a third time, the email that was not delivered when the condition was satisfied the previous time is now delivered, along with the email for this instance. This pattern then repeats itself, with the next email not being sent followed by two emails being sent simulatneously when the condition is met again. The smtp server being used is Windows 2003, on an internal network. The email is being sent to an outlook account hosted on an exchange server that is also on this internal network. Here is the actionscript code that creates the SMTPMailer object: public var testMail:SMTPMailer = null; public function alertNotify() { Security.loadPolicyFile("crossdomain.xml"); this.testMail = new SMTPMailer("myserver.ec.local",25); this.testMail.addEventListener(SMTPEvent.MAIL_SENT, onEmailEvent); this.testMail.addEventListener(SMTPEvent.MAIL_ERROR, onEmailError); this.testMail.addEventListener(SMTPEvent.DISCONNECTED, onEmailConn); this.testMail.addEventListener(SecurityErrorEvent.SECURITY_ERROR, onEmailError); } Here is the code that creates the email body and calls the method to send the email: public function alertUser(emailAC:ArrayCollection):void { trace ("In alertUser() before send, testMail.connected = " + testMail.connected.toString()); var testStr:String = " Key Location Event Type Comment Update Time "; for each (var event:rEntity in emailAC) { testStr = testStr + "" + event.key.toString() + "" + event.xml.address.toString() + " " + [email protected]() + "" + [email protected]() + "" + [email protected]() + "" + event.xml.attribute("update-time").toXMLString() + ""; } testStr = testStr + ""; testMail.flush(); testMail.sendHTMLMail("[email protected]","[email protected]","Event Notification",testStr); } Really not sure where the email that gets hung up is being stored until it is finally sent.... Any suggestions as to how to begin to remedy this issue would be much appreciated.

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  • Unresolved External Symbol linker error (C++)

    - by Niranjan
    Hi, I am trying to develop abstract design pattern code for one of my project as below.. But, I am not able to compile the code ..giving some compile errors(like "unresolved external symbol "public: virtual void __thiscall Xsecs::draw_lines(double,double)" (?draw_lines@Xsecs@@UAEXNN@Z)" ).. Can any one please help me out in this... #include "stdafx.h" #include <iostream> #include <vector> #include "Xsecs.h" using namespace std; //Product class class Xsecs { public: virtual void draw_lines(double pt1, double pt2); virtual void draw_curves(double pt1, double rad); }; class polyline: public Xsecs { public: virtual void draw_lines(double pt1,double pt2) { cout<<"draw_line in polygon"<<endl; } virtual void draw_curves(double pt1, double rad) { cout<<"Draw_curve in circle"<<endl; } /*void create_polygons() { cout<<"create_polygon_thru_draw_lines"<<endl; }*/ }; class circle: public Xsecs { public: virtual void draw_lines(double pt1,double pt2) { cout<<"draw_line in polygon"<<endl; } virtual void draw_curves(double pt1, double rad) { cout<<"Draw_curve in circle"<<endl; } /*void create_circles() { cout<<"Create circle"<<endl; }*/ }; //Factory class class Factory { public: virtual polyline* create_polyline()=0; virtual circle* create_circle()=0; }; class Factory1: public Factory { public: polyline* create_polyline() { return new polyline(); } circle* create_circle() { return new circle(); } }; class Factory2: public Factory { public: circle* create_circle() { return new circle(); } polyline* create_polyline() { return new polyline(); } }; int _tmain(int argc, _TCHAR* argv[]) { Factory1 f1; Factory * fp=&f1; return 0; }

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  • Is it ok to dynamic cast "this" as a return value?

    - by Panayiotis Karabassis
    This is more of a design question. I have a template class, and I want to add extra methods to it depending on the template type. To practice the DRY principle, I have come up with this pattern (definitions intentionally omitted): template <class T> class BaseVector: public boost::array<T, 3> { protected: BaseVector<T>(const T x, const T y, const T z); public: bool operator == (const Vector<T> &other) const; Vector<T> operator + (const Vector<T> &other) const; Vector<T> operator - (const Vector<T> &other) const; Vector<T> &operator += (const Vector<T> &other) { (*this)[0] += other[0]; (*this)[1] += other[1]; (*this)[2] += other[2]; return *dynamic_cast<Vector<T> * const>(this); } } template <class T> class Vector : public BaseVector<T> { public: Vector<T>(const T x, const T y, const T z) : BaseVector<T>(x, y, z) { } }; template <> class Vector<double> : public BaseVector<double> { public: Vector<double>(const double x, const double y, const double z); Vector<double>(const Vector<int> &other); double norm() const; }; I intend BaseVector to be nothing more than an implementation detail. This works, but I am concerned about operator+=. My question is: is the dynamic cast of the this pointer a code smell? Is there a better way to achieve what I am trying to do (avoid code duplication, and unnecessary casts in the user code)? Or am I safe since, the BaseVector constructor is private?

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  • How do you create a MANIFEST.MF that's available when you're testing and running from a jar in produ

    - by warvair
    I've spent far too much time trying to figure this out. This should be the simplest thing and everyone who distributes Java applications in jars must have to deal with it. I just want to know the proper way to add versioning to my Java app so that I can access the version information when I'm testing, e.g. debugging in Eclipse and running from a jar. Here's what I have in my build.xml: <target name="jar" depends = "compile"> <property name="version.num" value="1.0.0"/> <buildnumber file="build.num"/> <tstamp> <format property="TODAY" pattern="yyyy-MM-dd HH:mm:ss" /> </tstamp> <manifest file="${build}/META-INF/MANIFEST.MF"> <attribute name="Built-By" value="${user.name}" /> <attribute name="Built-Date" value="${TODAY}" /> <attribute name="Implementation-Title" value="MyApp" /> <attribute name="Implementation-Vendor" value="MyCompany" /> <attribute name="Implementation-Version" value="${version.num}-b${build.number}"/> </manifest> <jar destfile="${build}/myapp.jar" basedir="${build}" excludes="*.jar" /> </target> This creates /META-INF/MANIFEST.MF and I can read the values when I'm debugging in Eclipse thusly: public MyClass() { try { InputStream stream = getClass().getResourceAsStream("/META-INF/MANIFEST.MF"); Manifest manifest = new Manifest(stream); Attributes attributes = manifest.getMainAttributes(); String implementationTitle = attributes.getValue("Implementation-Title"); String implementationVersion = attributes.getValue("Implementation-Version"); String builtDate = attributes.getValue("Built-Date"); String builtBy = attributes.getValue("Built-By"); } catch (IOException e) { logger.error("Couldn't read manifest."); } } But, when I create the jar file, it loads the manifest of another jar (presumably the first jar loaded by the application - in my case, activation.jar). Also, the following code doesn't work either although all the proper values are in the manifest file. Package thisPackage = getClass().getPackage(); String implementationVersion = thisPackage.getImplementationVersion(); Any ideas?

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  • can this code be broken?

    - by user105165
    Consider the below html string <p>This is a paragraph tag</p> <font>This is a font tag</font> <div>This is a div tag</div> <span>This is a span tag</span> This string is processed to tokanize the text found in it and we get 2 results as below 1) Token Array : $tokenArray == array( 'This is a paragraph tag', 'This is a div tag', '<font>This is a font tag</font>', '<span>This is a span tag</span>' ); 2) Tokenized template : $templateString == "<p>{0}</p>{2}<div>{1}</div>{3}"; If you observe, the sequence of the text strings segments from the original HTML strings is different from the tokenized template The PHP code below is used to order the tokenized template and accordingly the token array to match the original html string class CreateTemplates { public static $tokenArray = array(); public static $tokenArrayNew = array(); function foo($templateString,$tokenArray) { CreateTemplates::$tokenArray = $tokenArray; $ptn = "/{[0-9]*}*/"; // Search Pattern from the template string $templateString = preg_replace_callback($ptn,array(&$this, 'callbackhandler') ,$templateString); // function call return $templateString; } // Function defination private static function callbackhandler($matches) { static $newArr = array(); static $cnt; $tokenArray = CreateTemplates::$tokenArray; array_push($newArr, $matches[0]); CreateTemplates::$tokenArrayNew[count($newArr)] = $tokenArray[substr($matches[0],1,(strlen($matches[0])-2))]; $cnt = count($newArr)-1; return '{'.$cnt.'}'; } // function ends } // class ends Final output is (ordered template and token array) $tokenArray == array('This is a paragraph tag', '<font>This is a font tag</font>', 'This is a div tag', '<span>This is a span tag</span>' ); $templateString == "<p>{0}</p>{1}<div>{2}</div>{3}"; Which is the expected result. Now, I am not confident whether this is the right way to achieve this. I want to see how this code can be broken or not. Under what conditions will this code break? (important) Is there any other way to achieve this? (less important)

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  • Design patterns and interview question

    - by user160758
    When I was learning to code, I read up on the design patterns like a good boy. Long after this, I started to actually understand them. Design discussions such as those on this site constantly try to make the rules more and more general, which is good. But there is a line, over which it becomes over-analysis starts to feed off itself and as such I think begins to obfuscate the original point - for example the "What's Alternative to Singleton" post and the links contained therein. http://stackoverflow.com/questions/1300655/whats-alternative-to-singleton I say this having been asked in both interviews I’ve had over the last 2 weeks what a singleton is and what criticisms I have of it. I have used it a few times for items such as user data (simple key-value eg. last file opened by this user) and logging (very common i'm sure). I've never ever used it just to have what is essentially global application data, as this is clearly stupid. In the first interview, I reply that I have no criticisms of it. He seemed disappointed by this but as the job wasn’t really for me, I forgot about it. In the next one, I was asked again and, as I wanted this job, I thought about it on the spot and made some objections, similar to those contained in the post linked to above (I suggested use of a factory or dependency injection instead). He seemed happy with this. But my problem is that I have used the singleton without ever using it in this kind of stupid way, which I had to describe on the spot. Using it for global data and the like isn’t something I did then realised was stupid, or read was stupid so didn’t do, it was just something I knew was stupid from the start. Essentially I’m supposed to be able to think of ways of how to misuse a pattern in the interview? Which class of programmers can best answer this question? The best ones? The medium ones? I'm not sure.... And these were both bright guys. I read more than enough to get better at my job but had never actually bothered to seek out criticisms of the most simple of the design patterns like this one. Do people think such questions are valid and that I ought to know the objections off by heart? Or that it is reasonable to be able to work out what other people who are missing the point would do on the fly? Or do you think I’m at least partially right that the question is too unsubtle and that the questions ought to be better thought out in order to make sure only good candidates can answer. PS. Please don’t think I’m saying that I’m just so clever that I know everything automatically - I’ve learnt the hard way like everyone else. But avoiding global data is hardly revolutionary.

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  • ActionResult - Service

    - by cem
    I bored, writing same code for service and ui. Then i tried to write a converter for simple actions. This converter, converting Service Results to MVC result, seems like good solution for me but anyway i think this gonna opposite MVC pattern. So here, I need help, what you think about algorithm - is this good or not? Thanks ServiceResult - Base: public abstract class ServiceResult { public static NoPermissionResult Permission() { return new NoPermissionResult(); } public static SuccessResult Success() { return new SuccessResult(); } public static SuccessResult<T> Success<T>(T result) { return new SuccessResult<T>(result); } protected ServiceResult(ServiceResultType serviceResultType) { _resultType = serviceResultType; } private readonly ServiceResultType _resultType; public ServiceResultType ResultType { get { return _resultType; } } } public class SuccessResult<T> : ServiceResult { public SuccessResult(T result) : base(ServiceResultType.Success) { _result = result; } private readonly T _result; public T Result { get { return _result; } } } public class SuccessResult : SuccessResult<object> { public SuccessResult() : this(null) { } public SuccessResult(object o) : base(o) { } } Service - eg. ForumService: public ServiceResult Delete(IVUser user, int id) { Forum forum = Repository.GetDelete(id); if (!Permission.CanDelete(user, forum)) { return ServiceResult.Permission(); } Repository.Delete(forum); return ServiceResult.Success(); } Controller: public class BaseController { public ActionResult GetResult(ServiceResult result) { switch (result.ResultType) { case ServiceResultType.Success: var successResult = (SuccessResult)result; return View(successResult.Result); break; case ServiceResultType.NoPermission: return View("Error"); break; default: return View(); break; } } } [HandleError] public class ForumsController : BaseController { [ValidateAntiForgeryToken] [Transaction] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Delete(int id) { ServiceResult result = ForumService.Delete(WebUser.Current, id); /* Custom result */ if (result.ResultType == ServiceResultType.Success) { TempData[ControllerEnums.GlobalViewDataProperty.PageMessage.ToString()] = "The forum was successfully deleted."; return this.RedirectToAction(ec => Index()); } /* Custom result */ /* Execute Permission result etc. */ TempData[ControllerEnums.GlobalViewDataProperty.PageMessage.ToString()] = "A problem was encountered preventing the forum from being deleted. " + "Another item likely depends on this forum."; return GetResult(result); } }

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  • Saving image from Gallery to db - Coursor IllegalStateException

    - by MyWay
    I want to save to db some strings with image. Image can be taken from gallery or user can set the sample one. In the other activity I have a listview which should present the rows with image and name. I'm facing so long this problem. It occurs when I wanna display listview with the image from gallery, If the sample image is saved in the row everything works ok. My problem is similar to this one: how to save image taken from camera and show it to listview - crashes with "IllegalStateException" but I can't find there the solution for me My table in db looks like this: public static final String KEY_ID = "_id"; public static final String ID_DETAILS = "INTEGER PRIMARY KEY AUTOINCREMENT"; public static final int ID_COLUMN = 0; public static final String KEY_NAME = "name"; public static final String NAME_DETAILS = "TEXT NOT NULL"; public static final int NAME_COLUMN = 1; public static final String KEY_DESCRIPTION = "description"; public static final String DESCRIPTION_DETAILS = "TEXT"; public static final int DESCRIPTION_COLUMN = 2; public static final String KEY_IMAGE ="image" ; public static final String IMAGE_DETAILS = "BLOP"; public static final int IMAGE_COLUMN = 3; //method which create our table private static final String CREATE_PRODUCTLIST_IN_DB = "CREATE TABLE " + DB_TABLE + "( " + KEY_ID + " " + ID_DETAILS + ", " + KEY_NAME + " " + NAME_DETAILS + ", " + KEY_DESCRIPTION + " " + DESCRIPTION_DETAILS + ", " + KEY_IMAGE +" " + IMAGE_DETAILS + ");"; inserting statement: public long insertToProductList(String name, String description, byte[] image) { ContentValues value = new ContentValues(); // get the id of column and value value.put(KEY_NAME, name); value.put(KEY_DESCRIPTION, description); value.put(KEY_IMAGE, image); // put into db return db.insert(DB_TABLE, null, value); } Button which add the picture and onActivityResult method which saves the image and put it into the imageview public void AddPicture(View v) { // creating specified intent which have to get data Intent intent = new Intent(Intent.ACTION_PICK); // From where we want choose our pictures intent.setType("image/*"); startActivityForResult(intent, PICK_IMAGE); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { // TODO Auto-generated method stub super.onActivityResult(requestCode, resultCode, data); // if identification code match to the intent, //if yes we know that is our picture, if(requestCode ==PICK_IMAGE ) { // check if the data comes with intent if(data!= null) { Uri chosenImage = data.getData(); String[] filePathColumn = {MediaStore.Images.Media.DATA}; Cursor cursor = getContentResolver().query(chosenImage, filePathColumn, null, null, null); cursor.moveToFirst(); int columnIndex = cursor.getColumnIndex(filePathColumn[0]); String filePat = cursor.getString(columnIndex); cursor.close(); ImageOfProduct = BitmapFactory.decodeFile(filePat); if(ImageOfProduct!=null) { picture.setImageBitmap(ImageOfProduct); } messageDisplayer("got picture, isn't null " + IdOfPicture); } } } Then the code which converts bitmap to byte[] public byte[] bitmapToByteConvert(Bitmap bit ) { // stream of data getted for compressed bitmap ByteArrayOutputStream gettedData = new ByteArrayOutputStream(); // compressing method bit.compress(CompressFormat.PNG, 0, gettedData); // our byte array return gettedData.toByteArray(); } The method which put data to the row: byte[] image=null; // if the name isn't put to the editView if(name.getText().toString().trim().length()== 0) { messageDisplayer("At least you need to type name of product if you want add it to the DB "); } else{ String desc = description.getText().toString(); if(description.getText().toString().trim().length()==0) { messageDisplayer("the description is set as none"); desc = "none"; } DB.open(); if(ImageOfProduct!= null){ image = bitmapToByteConvert(ImageOfProduct); messageDisplayer("image isn't null"); } else { BitmapDrawable drawable = (BitmapDrawable) picture.getDrawable(); image = bitmapToByteConvert(drawable.getBitmap()); } if(image.length>0 && image!=null) { messageDisplayer(Integer.toString(image.length)); } DB.insertToProductList(name.getText().toString(), desc, image ); DB.close(); messageDisplayer("well done you add the product"); finish(); You can see that I'm checking here the length of array to be sure that I don't send empty one. And here is the place where Error appears imo, this code is from activity which presents the listview with data taken from db private void LoadOurLayoutListWithInfo() { // firstly wee need to open connection with db db= new sqliteDB(getApplicationContext()); db.open(); // creating our custom adaprer, the specification of it will be typed // in our own class (MyArrayAdapter) which will be created below ArrayAdapter<ProductFromTable> customAdapter = new MyArrayAdapter(); //get the info from whole table tablecursor = db.getAllColumns(); if(tablecursor != null) { startManagingCursor(tablecursor); tablecursor.moveToFirst(); } // now we moving all info from tablecursor to ourlist if(tablecursor != null && tablecursor.moveToFirst()) { do{ // taking info from row in table int id = tablecursor.getInt(sqliteDB.ID_COLUMN); String name= tablecursor.getString(sqliteDB.NAME_COLUMN); String description= tablecursor.getString(sqliteDB.DESCRIPTION_COLUMN); byte[] image= tablecursor.getBlob(3); tablefromDB.add(new ProductFromTable(id,name,description,image)); // moving until we didn't find last row }while(tablecursor.moveToNext()); } listView = (ListView) findViewById(R.id.tagwriter_listoftags); //as description says // setAdapter = The ListAdapter which is responsible for maintaining //the data backing this list and for producing a view to represent //an item in that data set. listView.setAdapter(customAdapter); } I put the info from row tho objects which are stored in list. I read tones of question but I can't find any solution for me. Everything works when I put the sample image ( which is stored in app res folder ). Thx for any advice

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  • c++ compile error

    - by Niranjan
    Hi, I am trying to develop abstract design pattern code for one of my project as below.. But, I am not able to compile the code ..giving some compile errors(like "conversion from 'ProductA1 *' to 'ProductA *' exists, but is inaccessible" ).. Can any one please help me out in this... #include "stdafx.h" #include <iostream> using namespace std; class ProductA { public: virtual void Operation1()=0; virtual void Operation2()=0; }; class ProductA1 : ProductA { public: virtual void Operation1() {cout<<"PD ProductA1 Operation1"<<endl; } virtual void Operation2() {cout<<"PD ProductA1 Operation2"<<endl; } }; class ProductA2 : ProductA { public: virtual void Operation1() {cout<<"DT ProductA2 Operation1"<<endl; } virtual void Operation2() {cout<<"DT ProductA2 Operation2"<<endl; } }; //------------------------------------------------------------- class ProductB { public: virtual void Operation3()=0; virtual void Operation4()=0; }; class ProductB1 : ProductB { public: void Operation3() { cout<<"PD ProductB1 Operation3"<<endl; } void Operation4() { cout<<"PD ProductB1 Operation4"<<endl; } }; class ProductB2 : ProductB { public: void Operation3() { cout<<"DT ProductB2 Operation3"<<endl; } void Operation4() { cout<<"DT ProductB2 Operation4"<<endl; } }; //--------------- abstrct factory --------------------------- class Factory { public: virtual ProductA* CreateA () =0; virtual ProductB* CreateB ()=0; }; class Factory1 : Factory { public: ProductA* CreateA () { return new ProductA1(); } ProductB* CreateB () { return new ProductB1(); } }; class Factory2 : Factory { public: ProductA* CreateA () { return new ProductA2(); } ProductB* CreateB () { return new ProductB2(); } }; //--------------------- client -------------------------------- int _tmain(int argc, _TCHAR* argv[]) { Factory* pf = new Factory1(); ProductA *pa = pf->CreateA(); pa->Operation1(); pa->Operation2(); ProductB *pb = pf->CreateB(); pb->Operation3(); pb->Operation4(); return 0; }

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  • Problem setting row backgrounds in Android Listview

    - by zchtodd
    I have an application in which I'd like one row at a time to have a certain color. This seems to work about 95% of the time, but sometimes instead of having just one row with this color, it will allow multiple rows to have the color. Specifically, a row is set to have the "special" color when it is tapped. In rare instances, the last row tapped will retain the color despite a call to setBackgroundColor attempting to make it otherwise. private OnItemClickListener mDirectoryListener = new OnItemClickListener(){ public void onItemClick(AdapterView parent, View view, int pos, long id){ if (stdir.getStationCount() == pos) { stdir.moreStations(); return; } if (playingView != null) playingView.setBackgroundColor(Color.DKGRAY); view.setBackgroundColor(Color.MAGENTA); playingView = view; playStation(pos); } }; I have confirmed with print statements that the code setting the row to gray is always called. Can anyone imagine a reason why this code might intermittently fail? If there is a pattern or condition that causes it, I can't tell. I thought it might have something to do with the activity lifecycle setting the "playingView" variable back to null, but I can't reliably reproduce the problem by switching activities or locking the phone. private class DirectoryAdapter extends ArrayAdapter { private ArrayList<Station> items; public DirectoryAdapter(Context c, int resLayoutId, ArrayList<Station> stations){ super(c, resLayoutId, stations); this.items = stations; } public int getCount(){ return items.size() + 1; } public View getView(int position, View convertView, ViewGroup parent){ View v = convertView; LayoutInflater vi = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); if (position == this.items.size()) { v = vi.inflate(R.layout.morerow, null); return v; } Station station = this.items.get(position); v = vi.inflate(R.layout.songrow, null); if (station.playing) v.setBackgroundColor(Color.MAGENTA); else if (station.visited) v.setBackgroundColor(Color.DKGRAY); else v.setBackgroundColor(Color.BLACK); TextView title = (TextView)v.findViewById(R.id.title); title.setText(station.name); return v; } };

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  • Using Core Data Concurrently and Reliably

    - by John Topley
    I'm building my first iOS app, which in theory should be pretty straightforward but I'm having difficulty making it sufficiently bulletproof for me to feel confident submitting it to the App Store. Briefly, the main screen has a table view, upon selecting a row it segues to another table view that displays information relevant for the selected row in a master-detail fashion. The underlying data is retrieved as JSON data from a web service once a day and then cached in a Core Data store. The data previous to that day is deleted to stop the SQLite database file from growing indefinitely. All data persistence operations are performed using Core Data, with an NSFetchedResultsController underpinning the detail table view. The problem I am seeing is that if you switch quickly between the master and detail screens several times whilst fresh data is being retrieved, parsed and saved, the app freezes or crashes completely. There seems to be some sort of race condition, maybe due to Core Data importing data in the background whilst the main thread is trying to perform a fetch, but I'm speculating. I've had trouble capturing any meaningful crash information, usually it's a SIGSEGV deep in the Core Data stack. The table below shows the actual order of events that happen when the detail table view controller is loaded: Main Thread Background Thread viewDidLoad Get JSON data (using AFNetworking) Create child NSManagedObjectContext (MOC) Parse JSON data Insert managed objects in child MOC Save child MOC Post import completion notification Receive import completion notification Save parent MOC Perform fetch and reload table view Delete old managed objects in child MOC Save child MOC Post deletion completion notification Receive deletion completion notification Save parent MOC Once the AFNetworking completion block is triggered when the JSON data has arrived, a nested NSManagedObjectContext is created and passed to an "importer" object that parses the JSON data and saves the objects to the Core Data store. The importer executes using the new performBlock method introduced in iOS 5: NSManagedObjectContext *child = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType]; [child setParentContext:self.managedObjectContext]; [child performBlock:^{ // Create importer instance, passing it the child MOC... }]; The importer object observes its own MOC's NSManagedObjectContextDidSaveNotification and then posts its own notification which is observed by the detail table view controller. When this notification is posted the table view controller performs a save on its own (parent) MOC. I use the same basic pattern with a "deleter" object for deleting the old data after the new data for the day has been imported. This occurs asynchronously after the new data has been fetched by the fetched results controller and the detail table view has been reloaded. One thing I am not doing is observing any merge notifications or locking any of the managed object contexts or the persistent store coordinator. Is this something I should be doing? I'm a bit unsure how to architect this all correctly so would appreciate any advice.

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  • C++ - Breaking code implementation into different parts

    - by Kotti
    Hi! The question plot (a bit abstract, but answering this question will help me in my real app): So, I have some abstract superclass for objects that can be rendered on the screen. Let's call it IRenderable. struct IRenderable { // (...) virtual void Render(RenderingInterface& ri) = 0; virtual ~IRenderable() { } }; And suppose I also have some other objects that derive from IRenderable, e.g. Cat and Dog. So far so good. I add some Cat and Dog specific methods, like SeekForWhiskas(...) and Bark(...). After that I add specific Render(...) method for them, so my code looks this way: class Cat : public IRenderable { public: void SeekForWhiskas(...) { // Implementation could be here or moved // to a source file (depends on me wanting // to inline it or not) } virtual void Render(...) { // Here comes the rendering routine, that // is specific for cats SomehowDrawAppropriateCat(...); } }; class Dog : public IRenderable { public: void Bark(...) { // Same as for 'SeekForWhiskas(...)' } virtual void Render(...) { // Here comes the rendering routine, that // is specific for dogs DrawMadDog(...); } }; And then somewhere else I can do drawing the way that an appropriate rendering routine is called: IRenderable* dog = new Dog(); dog->Render(...); My question is about logical wrapping of such kind of code. I want to break apart the code, that corresponds to rendering of the current object and it's own methods (Render and Bark in this example), so that my class implementation doesn't turn into a mess (imagine that I have 10 methods like Bark and of course my Render method doesn't fit in their company and would be hard to find). Two ways of making what I want to (as far as I know) are: Making appropriate routines that look like RenderCat(Cat& cat, RenderInterface* ri), joining them to render namespace and then the functions inside a class would look like virtual void Render(...) { RenderCat(*this, ...); }, but this is plain stupid, because I'll lose access to Cat's private members and friending these functions looks like a total design disaster. Using visitor pattern, but this would also mean I have to rebuild my app's design and looks like an inadequate way to make my code complicated from the very beginning. Any brilliant ideas? :)

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  • C++ game designing & polymorphism question

    - by Kotti
    Hi! I'm trying to implement some sort of 'just-for-me' game engine and the problem's plot goes the following way: Suppose I have some abstract interface for a renderable entity, e.g. IRenderable. And it's declared the following way: interface IRenderable { // (...) // Suppose that Backend is some abstract backend used // for rendering, and it's implementation is not important virtual void Render(Backend& backend) = 0; }; What I'm doing right now is something like declaring different classes like class Ball : public IRenderable { virtual void Render(Backend& backend) { // Rendering implementation, that is specific for // the Ball object // (...) } }; And then everything looks fine. I can easily do something like std::vector<IRenderable*> items, push some items like new Ball() in this vector and then make a call similiar to foreach (IRenderable* in items) { item->Render(backend); } Ok, I guess it is the 'polymorphic' way, but what if I want to have different types of objects in my game and an ability to manipulate their state, where every object can be manipulated via it's own interface? I could do something like struct GameState { Ball ball; Bonus bonus; // (...) }; and then easily change objects state via their own methods, like ball.Move(...) or bonus.Activate(...), where Move(...) is specific for only Ball and Activate(...) - for only Bonus instances. But in this case I lose the opportunity to write foreach IRenderable* simply because I store these balls and bonuses as instances of their derived, not base classes. And in this case the rendering procedure turns into a mess like ball.Render(backend); bonus.Render(backend); // (...) and it is bad because we actually lose our polymorphism this way (no actual need for making Render function virtual, etc. The other approach means invoking downcasting via dynamic_cast or something with typeid to determine the type of object you want to manipulate and this looks even worse to me and this also breaks this 'polymorphic' idea. So, my question is - is there some kind of (probably) alternative approach to what I want to do or can my current pattern be somehow modified so that I would actually store IRenderable* for my game objects (so that I can invoke virtual Render method on each of them) while preserving the ability to easily change the state of these objects? Maybe I'm doing something absolutely wrong from the beginning, if so, please point it out :) Thanks in advance!

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  • What is the best way to return two values from a method?

    - by Edward Tanguay
    When I have to write methods which return two values, I usually go about it as in the following code which returns a List<string>. Or if I have to return e.g. a id and string, then I return a List<object> and then pick them out with index number and recast the values. This recasting and referencing by index seems inelegant so I want to develop a new habit for methods that return two values. What is the best pattern for this? using System; using System.Collections.Generic; using System.Linq; namespace MultipleReturns { class Program { static void Main(string[] args) { string extension = "txt"; { List<string> entries = GetIdCodeAndFileName("first.txt", extension); Console.WriteLine("{0}, {1}", entries[0], entries[1]); } { List<string> entries = GetIdCodeAndFileName("first", extension); Console.WriteLine("{0}, {1}", entries[0], entries[1]); } Console.ReadLine(); } /// <summary> /// gets "first.txt", "txt" and returns "first", "first.txt" /// gets "first", "txt" and returns "first", "first.txt" /// it is assumed that extensions will always match /// </summary> /// <param name="line"></param> public static List<string> GetIdCodeAndFileName(string line, string extension) { if (line.Contains(".")) { List<string> parts = line.BreakIntoParts("."); List<string> returnItems = new List<string>(); returnItems.Add(parts[0]); returnItems.Add(line); return returnItems; } else { List<string> returnItems = new List<string>(); returnItems.Add(line); returnItems.Add(line + "." + extension); return returnItems; } } } public static class StringHelpers { public static List<string> BreakIntoParts(this string line, string separator) { if (String.IsNullOrEmpty(line)) return null; else { return line.Split(new string[] { separator }, StringSplitOptions.None).Select(p => p.Trim()).ToList(); } } } }

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  • Do you use an exception class in your Perl programs? Why or why not?

    - by daotoad
    I've got a bunch of questions about how people use exceptions in Perl. I've included some background notes on exceptions, skip this if you want, but please take a moment to read the questions and respond to them. Thanks. Background on Perl Exceptions Perl has a very basic built-in exception system that provides a spring-board for more sophisticated usage. For example die "I ate a bug.\n"; throws an exception with a string assigned to $@. You can also throw an object, instead of a string: die BadBug->new('I ate a bug.'); You can even install a signal handler to catch the SIGDIE psuedo-signal. Here's a handler that rethrows exceptions as objects if they aren't already. $SIG{__DIE__} = sub { my $e = shift; $e = ExceptionObject->new( $e ) unless blessed $e; die $e; } This pattern is used in a number of CPAN modules. but perlvar says: Due to an implementation glitch, the $SIG{DIE} hook is called even inside an eval(). Do not use this to rewrite a pending exception in $@ , or as a bizarre substitute for overriding CORE::GLOBAL::die() . This strange action at a distance may be fixed in a future release so that $SIG{DIE} is only called if your program is about to exit, as was the original intent. Any other use is deprecated. So now I wonder if objectifying exceptions in sigdie is evil. The Questions Do you use exception objects? If so, which one and why? If not, why not? If you don't use exception objects, what would entice you to use them? If you do use exception objects, what do you hate about them, and what could be better? Is objectifying exceptions in the DIE handler a bad idea? Where should I objectify my exceptions? In my eval{} wrapper? In a sigdie handler? Are there any papers, articles or other resources on exceptions in general and in Perl that you find useful or enlightening.

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  • Can I write a test that succeeds if and only if a statement does not compile?

    - by Billy ONeal
    I'd like to prevent clients of my class from doing something stupid. To that end, I have used the type system, and made my class only accept specific types as input. Consider the following example (Not real code, I've left off things like virtual destructors for the sake of example): class MyDataChunk { //Look Ma! Implementation! }; class Sink; class Source { virtual void Run() = 0; Sink *next_; void SetNext(Sink *next) { next_ = next; } }; class Sink { virtual void GiveMeAChunk(const MyDataChunk& data) { //Impl }; }; class In { virtual void Run { //Impl } }; class Out { }; //Note how filter and sorter have the same declaration. Concrete classes //will inherit from them. The seperate names are there to ensure only //that some idiot doesn't go in and put in a filter where someone expects //a sorter, etc. class Filter : public Source, public Sink { //Drop objects from the chain-of-command pattern that don't match a particular //criterion. }; class Sorter : public Source, public Sink { //Sorts inputs to outputs. There are different sorters because someone might //want to sort by filename, size, date, etc... }; class MyClass { In i; Out o; Filter f; Sorter s; public: //Functions to set i, o, f, and s void Execute() { i.SetNext(f); f.SetNext(s); s.SetNext(o); i.Run(); } }; What I don't want is for somebody to come back later and go, "Hey, look! Sorter and Filter have the same signature. I can make a common one that does both!", thus breaking the semantic difference MyClass requires. Is this a common kind of requirement, and if so, how might I implement a test for it?

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  • Read from file in eclipse

    - by Buzkie
    I'm trying to read from a text file to input data to my java program. However, eclipse continuosly gives me a Source not found error no matter where I put the file. I've made an additional sources folder in the project directory, the file in question is in both it and the bin file for the project and it still can't find it. I even put a copy of it on my desktop and tried pointing eclipse there when it asked me to browse for the source lookup path. No matter what I do it can't find the file. here's my code in case it's pertinent: System.out.println(System.getProperty("user.dir")); File file = new File("file.txt"); Scanner scanner = new Scanner(file); in addition, it says the user directory is the project directory and there is a copy there too. I have no clue what to do. Thanks, Alex after attempting the suggestion below and refreshing again, I was greeted by a host of errors. FileNotFoundException(Throwable).<init>(String) line: 195 FileNotFoundException(Exception).<init>(String) line: not available FileNotFoundException(IOException).<init>(String) line: not available FileNotFoundException.<init>(String) line: not available URLClassPath$JarLoader.getJarFile(URL) line: not available URLClassPath$JarLoader.access$600(URLClassPath$JarLoader, URL) line: not available URLClassPath$JarLoader$1.run() line: not available AccessController.doPrivileged(PrivilegedExceptionAction<T>) line: not available [native method] URLClassPath$JarLoader.ensureOpen() line: not available URLClassPath$JarLoader.<init>(URL, URLStreamHandler, HashMap) line: not available URLClassPath$3.run() line: not available AccessController.doPrivileged(PrivilegedExceptionAction<T>) line: not available [native method] URLClassPath.getLoader(URL) line: not available URLClassPath.getLoader(int) line: not available URLClassPath.access$000(URLClassPath, int) line: not available URLClassPath$2.next() line: not available URLClassPath$2.hasMoreElements() line: not available ClassLoader$2.hasMoreElements() line: not available CompoundEnumeration<E>.next() line: not available CompoundEnumeration<E>.hasMoreElements() line: not available ServiceLoader$LazyIterator.hasNext() line: not available ServiceLoader$1.hasNext() line: not available LocaleServiceProviderPool$1.run() line: not available AccessController.doPrivileged(PrivilegedExceptionAction<T>) line: not available [native method] LocaleServiceProviderPool.<init>(Class<LocaleServiceProvider>) line: not available LocaleServiceProviderPool.getPool(Class<LocaleServiceProvider>) line: not available NumberFormat.getInstance(Locale, int) line: not available NumberFormat.getNumberInstance(Locale) line: not available Scanner.useLocale(Locale) line: not available Scanner.<init>(Readable, Pattern) line: not available Scanner.<init>(ReadableByteChannel) line: not available Scanner.<init>(File) line: not available code used: System.out.println(System.getProperty("user.dir")); File file = new File(System.getProperty("user.dir") + "/file.txt"); Scanner scanner = new Scanner(file);

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  • Robust way to save/load objects with dependencies?

    - by mrteacup
    I'm writing an Android game in Java and I need a robust way to save and load application state quickly. The question seems to apply to most OO languages. To understand what I need to save: I'm using a Strategy pattern to control my game entities. The idea is I have a very general Entity class which e.g. stores the location of a bullet/player/enemy and I then attach a Behaviour class that tells the entity how to act: class Entiy { float x; float y; Behavior b; } abstract class Behavior { void update(Entity e); {} // Move about at a constant speed class MoveBehavior extends Behavior { float speed; void update ... } // Chase after another entity class ChaseBehavior extends Behavior { Entity target; void update ... } // Perform two behaviours in sequence class CombineBehavior extends Behavior { Behaviour a, b; void update ... } Essentially, Entity objects are easy to save but Behaviour objects can have a semi-complex graph of dependencies between other Entity objects and other Behaviour objects. I also have cases where a Behaviour object is shared between entities. I'm willing to change my design to make saving/loading state easier, but the above design works really well for structuring the game. Anyway, the options I've considered are: Use Java serialization. This is meant to be really slow in Android (I'll profile it sometime). I'm worried about robustness when changes are made between versions however. Use something like JSON or XML. I'm not sure how I would cope with storing the dependencies between objects however. Would I have to give each object a unique ID and then use these IDs on loading to link the right objects together? I thought I could e.g. change the ChaseBehaviour to store a ID to an entity, instead of a reference, that would be used to look up the Entity before performing the behaviour. I'd rather avoid having to write lots of loading/saving code myself as I find it really easy to make mistakes (e.g. forgetting to save something, reading things out in the wrong order). Can anyone give me any tips on good formats to save to or class designs that make saving state easier?

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  • cakephp datetime insertion behaviour

    - by littlechad
    hi everyone this is a cakePHP question about datetime database insertion mismatch, i jumped in to this project while the whole thing is already built around 70%. here's what happen, every time i insert a data that contain a datetime, the inserted time doesn't match the inputted date, and the mismatch has no pattern or what ever, in some table the differences is 5 hours, while in others it could be 12 hours, 7 hours, or even 15 hours. i have traced this by investigating the controller, the model, the app_controller, everything but i don't find anything that indicate a datetime insertion rules. if the view : echo $form->input('start_date', array('label' => __l('start date')); i can't even find in the controller anything like: $this->data['current_controller']['start_date'] = $this->data['current_controller']['start_date']; when i use pr($this-data); to print the posted data, this is shown: [start_date] => Array ( [month] => 02 [day] => 16 [year] => 2011 [hour] => [min] => [meridian] => ) so i figured doing something like: $yearMonDay = $this->data['current_controller']['start_date']['year']."-"; $yearMonDay .= $this->data['current_controller']['start_date']['month']."-"; $yearMonDay .= $this->data['current_controller']['start_date']['day']; if(!empty($this->data['current_controller']['start_date']['hour'])){ $hourMinSec = $this->data['current_controller']['start_date']['hour'].":"; $hourMinSec .= $this->data['current_controller']['start_date']['min'].":"; $hourMinSec .= $this->data['current_controller']['start_date']['meridian']; }else{ $hourMinSec = "00:00:00"; } $this->data['Deal']['start_date'] = $yearMonDay." ".$hourMinSec; just to make sure the funny thing is that those posted datetime is inserted into the database with the mismatch value anyway. it's getting pretty frustrating, is there any suggestion on where else should i find the codes that define how the datetime should be inserted? or probably give me a clue on how to override those mismatched insertion rules? thanks

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  • php regex guitar tab (tabs or tablature, a type of music notation)

    - by John
    I am in the process of creating a guitar tab to rtttl (Ring Tone Text Transfer Language) converter in PHP. In order to prepare a guitar tab for rtttl conversion I first strip out all comments (comments noted by #- and ended with -#), I then have a few lines that set tempo, note the tunning and define multiple instruments (Tempo 120\nDefine Guitar 1\nDefine Bass 1, etc etc) which are stripped out of the tab and set aside for later use. Now I essentially have nothing left except the guitar tabs. Each tab is prefixed with it's instrument name in conjunction with the instrument name noted prior. Some times we have tabs for 2 separate instruments that are linked because they are to be played together, ie a Guitar and a Bass Guitar playing together. Example 1, Standard Guitar Tab: |Guitar 1 e|--------------3-------------------3------------| B|------------3---3---------------3---3----------| G|----------0-------0-----------0-------0--------| D|--------0-----------0-------0-----------0------| A|------2---------------2---2---------------2----| E|----3-------------------3-------------------3--| Example 2, Conjunction Tab: |Guitar 1 e|--------------3-------------------3------------| B|------------3---3---------------3---3----------| G|----------0-------0-----------0-------0--------| D|--------0-----------0-------0-----------0------| A|------2---------------2---2---------------2----| E|----3-------------------3-------------------3--| | | |Bass 1 G|----------0-------0-----------0-------0--------| D|--------2-----------2-------2-----------2------| A|------3---------------3---3---------------3----| E|----3-------------------3-------------------3--| I have considered other methods of identifying the tabs with no solid results. I am hoping that someone who does regular expressions could help me find a way to identify a single guitar tab and if possible also be able to match a tab with multiple instruments linked together. Once the tabs are in an array I will go through them one line at a time and convert them into rtttl lines (exploded at each new line "\n"). I do not want to separate the guitar tabs in the document via explode "\n\n" or something similar because it does not identify the guitar tab, rather, it is identifying the space between the tabs - not on the tabs themselves. I have been messing with this for about a week now and this is the only major hold up I have. Everything else is fairly simple. As of current, I have tried many variations of the regex pattern. Here is one of the most recent test samples: <?php $t = " |Guitar 1 e|--------------3-------------------3------------| B|------------3---3---------------3---3----------| G|----------0-------0-----------0-------0--------| D|--------0-----------0-------0-----------0------| A|------2---------------2---2---------------2----| E|----3-------------------3-------------------3--| |Guitar 1 e|--------------3-------------------3------------| B|------------3---3---------------3---3----------| G|----------0-------0-----------0-------0--------| D|--------0-----------0-------0-----------0------| A|------2---------------2---2---------------2----| E|----3-------------------3-------------------3--| | | |Bass 1 G|----------0-------0-----------0-------0--------| D|--------2-----------2-------2-----------2------| A|------3---------------3---3---------------3----| E|----3-------------------3-------------------3--| "; preg_match_all("/^.*?(\\|).*?(\\|)/is",$t,$p); print_r($p); ?> It is also worth noting that inside the tabs, where the dashes and #'s are, you may also have any variation of letters, numbers and punctuation. The beginning of each line marks the tuning of each string with one of the following case insensitive: a,a#,b,c,c#,d,d#,e,f,f#,g or g. Thanks in advance for help with this most difficult problem.

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  • Separation of domain and ui layer in a composite

    - by hansmaad
    Hi all, i'm wondering if there is a pattern how to separate the domain logic of a class from the ui responsibilities of the objects in the domain layer. Example: // Domain classes interface MachinePart { CalculateX(in, out) // Where do we put these: // Draw(Screen) ?? // ShowProperties(View) ?? // ... } class Assembly : MachinePart { CalculateX(in, out) subParts } class Pipe : MachinePart { CalculateX(in, out) length, diamater... } There is an application that calculates the value X for machines assembled from many machine parts. The assembly is loaded from a file representation and is designed as a composite. Each concrete part class stores some data to implement the CalculateX(in,out) method to simulate behaviour of the whole assembly. The application runs well but without GUI. To increase the usability a GUi should be developed on top of the existing implementation (changes to the existing code are allowed). The GUI should show a schematic graphical representation of the assembly and provide part specific dialogs to edit several parameters. To achieve these goals the application needs new functionality for each machine part to draw a schematic representation on the screen, show a property dialog and other things not related to the domain of machine simulation. I can think of some different solutions to implement a Draw(Screen) functionality for each part but i am not happy with each of them. First i could add a Draw(Screen) method to the MachinePart interface but this would mix-up domain code with ui code and i had to add a lot of functionality to each machine part class what makes my domain model hard to read and hard to understand. Another "simple" solution is to make all parts visitable and implement ui code in visitors but Visitor does not belong to my favorite patterns. I could derive UI variants from each machine part class to add the UI implementation there but i had to check if each part class is suited for inheritance and had to be careful on changes to the base classes. My currently favorite design is to create a parallel composite hierarchy where each component stores data to define a machine part, has implementation for UI methods and a factory method which creates instances of the corresponding domain classes, so that i can "convert" a UI assembly to a domain assembly. But there are problems to go back from the created domain hierarchy to the UI hierarchy for showing calculation results in the drawing for example (imagine some parts store some values during the calculation i want to show in the schematic representation after the simluation). Maybe there are some proven patterns for such problems?

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  • Persistence scheme & state data for low memory situations (iphone)

    - by Robin Jamieson
    What happens to state information held by a class's variable after coming back from a low memory situation? I know that views will get unloaded and then reloaded later but what about some ancillary classes & data held in them that's used by the controller that launched the view? Sample scenario in question: @interface MyCustomController: UIViewController { ServiceAuthenticator *authenticator; } -(id)initWithAuthenticator:(ServiceAuthenticator *)auth; // the user may press a button that will cause the authenticator // to post some data to the service. -(IBAction)doStuffButtonPressed:(id)sender; @end @interface ServiceAuthenticator { BOOL hasValidCredentials; // YES if user's credentials have been validated NSString *username; NSString *password; // password is not stored in plain text } -(id)initWithUserCredentials:(NSString *)username password:(NSString *)aPassword; -(void)postData:(NSString *)data; @end The app delegate creates the ServiceAuthenticator class with some user data (read from plist file) and the class logs the user with the remote service. inside MyAppDelegate's applicationDidFinishLaunching: - (void)applicationDidFinishLaunching:(UIApplication *)application { ServiceAuthenticator *auth = [[ServiceAuthenticator alloc] initWithUserCredentials:username password:userPassword]; MyCustomController *controller = [[MyCustomController alloc] initWithNibName:...]; controller.authenticator = auth; // Configure and show the window [window addSubview:..]; // make everything visible [window makeKeyAndVisible]; } Then whenever the user presses a certain button, 'MyCustomController's doStuffButtonPressed' is invoked. -(IBAction)doStuffButtonPressed:(id)sender { [authenticator postData:someDataFromSender]; } The authenticator in-turn checks to if the user is logged in (BOOL variable indicates login state) and if so, exchanges data with the remote service. The ServiceAuthenticator is the kind of class that validates the user's credentials only once and all subsequent calls to the object will be to postData. Once a low memory scenario occurs and the associated nib & MyCustomController will get unloaded -- when it's reloaded, what's the process for resetting up the 'ServiceAuthenticator' class & its former state? I'm periodically persisting all of the data in my actual model classes. Should I consider also persisting the state data in these utility style classes? Is that the pattern to follow?

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  • How do make dependency generation work for C? (Also..decode this sed/make statement!)

    - by Derek
    Hi all. I have a make build system that I am trying to decipher that someone else wrote. I am getting an error when I run it on a redhat system, but not when I run it on my solaris system. The versions of gmake are the same major revision (one off on minor revision). This is for building a C project, and the make system has a global Makefile.global that is inherited by each directory's local Makefile The Makefile.global has all the targets in it, starting with all: $(LIB) $(BIN) where LIB builds libs and BIN builds binaries. jumping down the targets I have $(LIB) : $(GEN_LIB) $(GEN_LIB) : $(GEN_DEPS) $(GEN_OBJS) $(AR) $(ARFLAGS) $(GEN_LIB) $(GEN_OBJS) $(GEN_DEPS) : @set -e; rm -f $@; \ $(CC) $(CDEP_FLAG) $(CFLAGS) $(INCDIRS) `basename $@ | sed 's/\.d/\.c/' | sed 's,^,$(HOME_SRC)/,'` | sed 's,\(.*\)\.o: ,$(GEN_OBJDIR)/\1.o $@ :,g' > [email protected] ; \ cat [email protected] > $@ ; \ cat [email protected] | cut -d: -f2 | grep '\.h' | sed 's,\.h,.h :,g' >> $@ ; \ rm [email protected] $(GEN_OBJS) : $(CC) $(CFLAGS) $(INCDIRS) -c $(*F).c -lmpi -o $@ I think these are all the relevant targets I need to include to answer my question. Definitions of those variables: CC = icc CDEP_FLAG = -M CFLAGS = various compiler flags ifdef type flags INCDIRS = include directory where all .h files are GEN_OBJDIR = /lib/objs HOME_SRC = . GEN_LIB = lib/$(LIB) GEN_DEPDIR=/lib/deps GEN_DEPS = $(addprefix $(GEN_DEPDIR)/,$(addsuffix .d,$(basename $(OBJS)))) I think this has everything covered you need. Basically self explanatory from the names. Now as best I can tell, this is generating in /lib/deps a .d file that has the object and source dependencies in it. In other words, for the utilities.a library, I will get a utils.o and utils.c dependency stack, all in the file utils.d There is some syntax error that is being generated in that file I think, because I get the following error: ../lib/deps/util.d:25: *** target pattern contains no '%'. Stop. gmake[2]: *** [all] Error 2 gmake[1]: *** [all] Error 2 gmake: *** [all] Error 2 I am not sure if my error is in the dependency generation, or some further down part, like the object generation target? If you need further info, let me know, I will add to post

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