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  • Efficient database access when dealing with multiple abstracted repositories

    - by Nathan Ridley
    I want to know how most people are dealing with the repository pattern when it involves hitting the same database multiple times (sometimes transactionally) and trying to do so efficiently while maintaining database agnosticism and using multiple repositories together. Let's say we have repositories for three different entities; Widget, Thing and Whatsit. Each repository is abstracted via a base interface as per normal decoupling design processes. The base interfaces would then be IWidgetRepository, IThingRepository and IWhatsitRepository. Now we have our business layer or equivalent (whatever you want to call it). In this layer we have classes that access the various repositories. Often the methods in these classes need to do batch/combined operations where multiple repositories are involved. Sometimes one method may make use of another method internally, while that method can still be called independently. What about, in this scenario, when the operation needs to be transactional? Example: class Bob { private IWidgetRepository _widgetRepo; private IThingRepository _thingRepo; private IWhatsitRepository _whatsitRepo; public Bob(IWidgetRepository widgetRepo, IThingRepository thingRepo, IWhatsitRepository whatsitRepo) { _widgetRepo = widgetRepo; _thingRepo= thingRepo; _whatsitRepo= whatsitRepo; } public void DoStuff() { _widgetRepo.StoreSomeStuff(); _thingRepo.ReadSomeStuff(); _whatsitRepo.SaveSomething(); } public void DoOtherThing() { _widgetRepo.UpdateSomething(); DoStuff(); } } How do I keep my access to that database efficient and not have a constant stream of open-close-open-close on connections and inadvertent invocation of MSDTS and whatnot? If my database is something like SQLite, standard mechanisms like creating nested transactions are going to inherently fail, yet the business layer should not have to be concerning itself with such things. How do you handle such issues? Does ADO.Net provide simple mechanisms to handle this or do most people end up wrapping their own custom bits of code around ADO.Net to solve these types of problems?

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  • How much is too much memory allocation in NDK?

    - by Maximus
    The NDK download page notes that, "Typical good candidates for the NDK are self-contained, CPU-intensive operations that don't allocate much memory, such as signal processing, physics simulation, and so on." I came from a C background and was excited to try to use the NDK to operate most of my OpenGL ES functions and any native functions related to physics, animation of vertices, etc... I'm finding that I'm relying quite a bit on Native code and wondering if I may be making some mistakes. I've had no trouble with testing at this point, but I'm curious if I may run into problems in the future. For example, I have game struct defined (somewhat like is seen in the San-Angeles example). I'm loading vertex information for objects dynamically (just what is needed for an active game area) so there's quite a bit of memory allocation happening for vertices, normals, texture coordinates, indices and texture graphic data... just to name the essentials. I'm quite careful about freeing what is allocated between game areas. Would I be safer setting some caps on array sizes or should I charge bravely forward as I'm going now?

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  • Is this a correct way to stop Execution Task

    - by Yan Cheng CHEOK
    I came across code to stop execution's task. private final ExecutorService executor = Executors.newSingleThreadExecutor(); public void stop() { executor.shutdownNow(); try { executor.awaitTermination(100, TimeUnit.DAYS); } catch (InterruptedException ex) { log.error(null, ex); } } public Runnable getRunnable() { return new Runnable() { public void run() { while (!Thread.currentThread().isInterrupted()) { // What if inside fun(), someone try to clear the interrupt flag? // Say, through Thread.interrupted(). We will stuck in this loop // forever. fun(); } } }; } I realize that, it is possible for Runnable to be in forever loop, as Unknown fun may Thread.sleep, clear the interrupt flag and ignore the InterruptedException Unknown fun may Thread.interrupted, clear the interrupt flag. I was wondering, is the following way correct way to fix the code? private final ExecutorService executor = Executors.newSingleThreadExecutor(); private volatile boolean flag = true; public void stop() { flag = false; executor.shutdownNow(); try { executor.awaitTermination(100, TimeUnit.DAYS); } catch (InterruptedException ex) { log.error(null, ex); } } public Runnable getRunnable() { return new Runnable() { public void run() { while (flag && !Thread.currentThread().isInterrupted()) { // What if inside fun(), someone try to clear the interrupt flag? // Say, through Thread.interrupted(). We will stuck in this loop // forever. fun(); } } }; }

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  • Constructing a WeakReference<T> throws COMException

    - by ChaseMedallion
    The following code: IDisposable d = ... new WeakReference<IDisposable>(d); Has started throwing the following exception on SOME machines. What could cause this? System.Runtime.InteropServices.COMException: Unspecified error (Exception from HRESULT: 0x80004005 (E_FAIL)) EDIT: the machines that experience the error are running Windows Server 2008 R2. Windows Server 2012 and desktop machines running windows 7 work fine. (this is true, but I now think a different issue is the relevant difference... see below). EDIT: as an additional note, this occurred right after updating our codebase to Entity Framework 6.1.1.-beta1. In the above code, The IDisposable is a class which wraps an EF DbContext. EDIT: why the votes to close? EDIT: the stack trace of the failure ends at the WeakReference<T> constructor called in the above code: at System.WeakReference`1..ctor(T target, Boolean trackResurrection) // from here on down it's code we wrote/simple LINQ. None of this code has changed recently; // we just upgraded to EF6 and saw this failure start happening at Core.Data.EntityFrameworkDataContext.RegisterDependentDisposable(IDisposable child) at Core.Data.ServiceFactory.GetConstructorParameter[TService](Type parameterType) at System.Linq.Enumerable.WhereSelectListIterator`2.MoveNext() at System.Linq.Buffer`1..ctor(IEnumerable`1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source) at Core.Data.ServiceFactory.CreateService[TService]() at MVC controller action method EDIT: it turns out that the machines having issues with this were running AppDynamics. Uninstalling that seems to have removed the issue.

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  • StoreFilterField input doesn't react

    - by user1289877
    I'm trying to build grid with build in column filtering (using sencha gxt), here is my code: public Grid<Stock> createGrid() { // Columns definition ColumnConfig<Stock, String> nameCol = new ColumnConfig<Stock, String>(props.name(), 100, "Company"); // Column model definition and creation List<ColumnConfig<Stock, ?>> cl = new ArrayList<ColumnConfig<Stock, ?>>(); cl.add(nameCol); ColumnModel<Stock> cm = new ColumnModel<Stock>(cl); // Data populating ListStore<Stock> store = new ListStore<Stock>(props.key()); store.addAll(TestData.getStocks()); // Grid creation with data final Grid<Stock> grid = new Grid<Stock>(store, cm); grid.getView().setAutoExpandColumn(nameCol); grid.setBorders(false); grid.getView().setStripeRows(true); grid.getView().setColumnLines(true); // Filters definition StoreFilterField<Stock> filter = new StoreFilterField<Stock>() { @Override protected boolean doSelect(Store<Stock> store, Stock parent, Stock item, String filter) { // Window.alert(String.valueOf("a")); String name = item.getName(); name = name.toLowerCase(); if (name.startsWith(filter.toLowerCase())) { return true; } return false; } }; filter.bind(store); cm.addHeaderGroup(0, 0, new HeaderGroupConfig(filter, 1, 1)); filter.focus(); return grid; } My problem is: after I run this code, I cannot write anything to filter input, I'm using test data and classes (Stock.java and StockProperties.java) from this example: http://sencha.com/examples-dev/#ExamplePlace:filtergrid I try to put allert in doSelect method to check if this function was called, but it wasn't. Any idea will be welcome. Thanks.

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  • Handle BACK key event in child view

    - by Mick Byrne
    In my app, users can tap on image thumbnails to see a full size version. When the thumbnail is tapped a bunch of new views are created in code (i.e. no XML), appended at the end of the view hierarchy and some scaling and rotating transitions happen, then the full size, high res version of the image is displayed. Tapping on the full size image reverses the transitions and removes the new views from the view hierarchy. I want users to also be able to press the BACK key to reverse the image transitions. However, I can't seem to catch the KeyEvent. This is what I'm trying at the moment: // Set a click listener on the image to reverse everything frameView.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { zoomOut(); // This works fine } }); // Set the focus onto the frame and then set a key listener to catch the back buttons frameView.setFocusable(true); frameView.setFocusableInTouchMode(true); frameView.requestFocus(); frameView.setOnKeyListener(new OnKeyListener() { @Override public boolean onKey(View v, int keyCode, KeyEvent event) { // The code never even gets here !!! if(keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) { zoomOut(); return true; } return false; } });

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  • Recursive Enumeration in Java

    - by Harm De Weirdt
    Hello everyone. I still have a question about Enumerations. Here's a quick sketch of the situation. I have a class Backpack that has a Hashmap content with as keys a variable of type long, and as value an ArrayList with Items. I have to write an Enumeration that iterates over the content of a Backpack. But here's the catch: in a Backpack, there can also be another Backpack. And the Enumeration should also be able to iterate over the content of a backpack that is in the backpack. (I hope you can follow, I'm not really good at explaining..) Here is the code I have: public Enumeration<Object> getEnumeration() { return new Enumeration<Object>() { private int itemsDone = 0; //I make a new array with all the values of the HashMap, so I can use //them in nextElement() Collection<Long> keysCollection = getContent().keySet(); Long [] keys = keysCollection.toArray(new Long[keysCollection.size()]); public boolean hasMoreElements() { if(itemsDone < getContent().size()) { return true; }else { return false; } } public Object nextElement() { ArrayList<Item> temporaryList= getContent().get(keys[itemsDone]); for(int i = 0; i < temporaryList.size(); i++) { if(temporaryList.get(i) instanceof Backpack) { return temporaryList.get(i).getEnumeration(); }else { return getContent().get(keys[itemsDone++]); } } } }; Will this code work decently? It's just the "return temporaryList.get(i).getEnumeration();" I'm worried about. Will the users still be able to use just the hasMoreElemens() and nextElement() like he would normally do? Any help is appreciated, Harm De Weirdt

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  • Can't call function from within onOptionsItemSelected

    - by Kristy Welsh
    public boolean onOptionsItemSelected(MenuItem item) { //check selected menu item switch (item.getItemId()) { case R.id.exit: this.finish(); return true; case R.id.basic: Difficulty = DIFFICULTY_BASIC; Toast.makeText(YogaPosesActivity.this, "Difficulty is Basic", Toast.LENGTH_SHORT).show(); SetImageView(myDbHelper); return true; case R.id.advanced: Toast.makeText(YogaPosesActivity.this, "Difficulty is Advanced", Toast.LENGTH_SHORT).show(); Difficulty = DIFFICULTY_ADVANCED; SetImageView(myDbHelper); return true; case R.id.allPoses: Toast.makeText(YogaPosesActivity.this, "All Poses Will Be Displayed", Toast.LENGTH_SHORT).show(); Difficulty = DIFFICULTY_ADVANCED_AND_BASIC; SetImageView(myDbHelper); return true; default: return super.onOptionsItemSelected(item); } } I get an error when I call the SetImageView function, which was defined out of the OnCreate Activity. Can you not call a function unless it was defined inside the OnCreate? I get a nullPointer Exception when calling the function.

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  • Getting problem in threading in JAVA

    - by chetans
    In this program i want to stop GenerateImage & MovingImage Thread both... And i want to start those threads from begining. Can u send me the solution? Here is the code........ package Game; import java.applet.Applet; import java.awt.Color; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Image; import java.awt.MediaTracker; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import java.net.MalformedURLException; import java.net.URL; public class ThreadInApplet extends Applet implements KeyListener { private static final long serialVersionUID = 1L; Image[] asteroidImage; Image spaceshipImage; String levelstr="Easy Level"; int[] XPos,YPos; int number=0,XPosOfSpaceship,YPosOfSpaceship,NoOfObstacles=5,speed=1,level=1,spaceBtnPressdCntr=0; boolean gameStart=false,pauseGame=false,collideUp=false,collideDown=false,collideLeft=false,collideRight=false; private Image offScreenImage; private Dimension offScreenSize; private Graphics offScreenGraphics; Thread GenerateImages,MoveImages; public void init() { try { GenerateImages=new Thread () //thread to create obstacles { synchronized public void run () { for(int g=0;g<NoOfObstacles;g++) { try { sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } number++; // Temporary counter to count the no of obstacles created } } } ; MoveImages=new Thread () //thread to move obstacles { @SuppressWarnings("deprecation") synchronized public void run () { while(YPos[NoOfObstacles-1]!=600) { pauseGame=false; if(collide()==true) { GenerateImages.suspend(); repaint(); } else GenerateImages.resume(); for(int l=0;l<number;l++) { if(collide()==false) YPos[l]++; else GenerateImages.suspend(); } repaint(); try { sleep(speed); } catch (InterruptedException e) { e.printStackTrace(); } } if(YPos[NoOfObstacles-1]>=600) //level complete state { level++; try { levelUpdation(level); System.out.println("aahe"); } catch (MalformedURLException e) { e.printStackTrace(); } repaint(); } } }; initialPos(); spaceshipImage=getImage(new URL(getCodeBase(),"images/space.png")); for(int i=0;i<NoOfObstacles;i++) { asteroidImage[i]=getImage(new URL(getCodeBase(),"images/asteroid.png")); XPos[i]=(int) (Math.random()*700); YPos[i]=0; } MediaTracker tracker = new MediaTracker (this); for(int i=0;i<NoOfObstacles;i++) { tracker.addImage (asteroidImage[i], 0); } } catch (MalformedURLException e) { e.printStackTrace(); } setBackground(Color.black); addKeyListener(this); } //Sets initial positions of spaceship & obstacle images------------------------------------------------------ public void initialPos() throws MalformedURLException { asteroidImage=new Image[NoOfObstacles]; XPos=new int[NoOfObstacles]; YPos=new int[NoOfObstacles]; XPosOfSpaceship=getWidth()/2-35; YPosOfSpaceship=getHeight()-100; collideUp = false; collideDown=false; collideLeft=false; collideRight=false; } //level finished updations------------------------------------------------------------------------------ @SuppressWarnings("deprecation") public void levelUpdation(int level) throws MalformedURLException { NoOfObstacles=NoOfObstacles+20; speed=speed-3; System.out.println(NoOfObstacles+" "+speed); pauseGame=true; initialPos(); repaint(); } //paint method of graphics to print the messages--------------------------------------------------------- public void paint(Graphics g) { g.setColor(Color.white); if(gameStart==false) { g.drawString("SPACE to start", (getWidth()/2)-15, getHeight()/2); g.drawString(levelstr, (getWidth()/2), getHeight()/2+20); } if(level>1) { if(level==2) levelstr="Medium Level"; else levelstr="High Level"; g.drawString("Level Complete ", (getWidth()/2)-15, getHeight()/2); g.drawString(levelstr, (getWidth()/2), getHeight()/2+20); //g.drawString("SPACE to start", (getWidth()/2)-15, getHeight()/2+40); } for(int n=0;n<number;n++) { if(n>0) g.drawImage(asteroidImage[n],XPos[n],YPos[n],this); } g.drawImage(spaceshipImage,XPosOfSpaceship,YPosOfSpaceship,this); } //update method of graphics to print the messages--------------------------------------------------------- @SuppressWarnings("deprecation") public void update(Graphics g) { Dimension d = size(); if((offScreenImage == null) || (d.width != offScreenSize.width) || (d.height != offScreenSize.height)) { offScreenImage = createImage(d.width, d.height); offScreenSize = d; offScreenGraphics = offScreenImage.getGraphics(); } offScreenGraphics.clearRect(0, 0, d.width, d.height); paint(offScreenGraphics); g.drawImage(offScreenImage, 0, 0, null); } public void keyReleased(KeyEvent arg0){} public void keyTyped(KeyEvent arg0) {} //---------------------Key pressed event to start game & to move the spaceship-------------------------------------- public void keyPressed(KeyEvent e) { if(e.getKeyCode()==32) { spaceBtnPressdCntr++; if(spaceBtnPressdCntr==1) { gameStart=true; GenerateImages.start(); MoveImages.start(); } } if(gameStart==true) { if(e.getKeyCode()==37) { new Thread () { @SuppressWarnings("deprecation") synchronized public void run () { for(int cnt1=1;cnt1<=10;cnt1++) { if(collide()==true && collideLeft == true) { GenerateImages.suspend(); } else { if(XPosOfSpaceship>0) XPosOfSpaceship--; } } repaint(); } }.start(); } if(e.getKeyCode()==38) { new Thread () { @SuppressWarnings("deprecation") synchronized public void run () { for(int cnt1=1;cnt1<=10;cnt1++) { if(collide()==true && collideUp == true) { GenerateImages.suspend(); } else { if(YPosOfSpaceship>10) YPosOfSpaceship--; } } repaint(); } }.start(); } if(e.getKeyCode()==39) { new Thread () { @SuppressWarnings("deprecation") synchronized public void run () { for(int cnt1=1;cnt1<=10;cnt1++) { if(collide()==true && collideRight == true) { GenerateImages.suspend(); } else { if(XPosOfSpaceship<750) XPosOfSpaceship++; } } repaint(); } }.start(); } if(e.getKeyCode()==40) { new Thread () { @SuppressWarnings("deprecation") synchronized public void run () { for(int cnt1=1;cnt1<=10;cnt1++) { if(collide()==true && collideDown == true) { GenerateImages.suspend(); } else { if(YPosOfSpaceship<550) YPosOfSpaceship++; } } repaint(); } }.start(); } } } //------------------------------Collision checking between Spaceship & obstacles------------------------------ public boolean collide() { int x1,y1,x2,y2,x3,y3,x4,y4; //coordinates of obstacles int a1,b1,a2,b2,a3,b3,a4,b4; //coordinates of spaceship a1 =XPosOfSpaceship; b1=YPosOfSpaceship; a2=a1+spaceshipImage.getWidth(this); b2=b1; a3=a1; b3=b1+spaceshipImage.getHeight(this); a4=a2; b4=b3; for(int a=0;a<number;a++) { x1 =XPos[a]; y1=YPos[a]; x2=x1+asteroidImage[a].getWidth(this); y2=y1; x3=x1; y3=y1+asteroidImage[a].getHeight(this); x4=x2; y4=y3; /********checking asteroid touch spaceship from up direction********/ if(y3==b1 && x4>=a1 && x4<=a2) { collideUp = true; collideDown=false; collideLeft=false; collideRight=false; return(true); } if(y3==b1 && x3>=a1 && x3<=a2) { collideUp = true; collideDown=false; collideLeft=false; collideRight=false; return(true); } /********checking asteroid touch spaceship from left direction******/ if(x2==a1 && y4>=b1 && y4<=b3) { collideLeft=true; collideUp = false; collideDown=false; collideRight=false; return(true); } if(x2==a1 && y2>=b1 && y2<=b3) { collideLeft=true; collideUp = false; collideDown=false; collideRight=false; return(true); } /********checking asteroid touch spaceship from right direction*****/ if(x1==a2 && y3>=b2 && y3<=b4) { collideRight=true; collideLeft=false; collideUp = false; collideDown=false; return(true); } if(x1==a2 && y1>=b2 && y1<=b4) { collideRight=true; collideLeft=false; collideUp = false; collideDown=false; return(true); } /********checking asteroid touch spaceship from down direction*****/ if(y1==b3 && x2>=a3 && x2<=a4) { collideDown=true; collideRight=false; collideLeft=false; collideUp = false; return(true); } if(y1==b3 && x1>=a3 && x1<=a4) { collideDown=true; collideRight=false; collideLeft=false; collideUp = false; return(true); } } return(false); } }

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  • Project Euler, Problem 10 java solution now working

    - by Dennis S
    Hi, I'm trying to find the sum of the prime numbers < 2'000'000. This is my solution in java but I can't seem get the correct answer. Please give some input on what could be wrong and general advice on the code is appreciated. Printing 'sum' gives: 1308111344, which is incorrect. /* The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. */ class Helper{ public void run(){ Integer sum = 0; for(int i = 2; i < 2000000; i++){ if(isPrime(i)) sum += i; } System.out.println(sum); } private boolean isPrime(int nr){ if(nr == 2) return true; else if(nr == 1) return false; if(nr % 2 == 0) return false; for(int i = 3; i < Math.sqrt(nr); i += 2){ if(nr % i == 0) return false; } return true; } } class Problem{ public static void main(String[] args){ Helper p = new Helper(); p.run(); } }

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  • Is locking on the requested object a bad idea?

    - by Quick Joe Smith
    Most advice on thread safety involves some variation of the following pattern: public class Thing { private static readonly object padlock = new object(); private string stuff, andNonsense; public string Stuff { get { lock (Thing.padlock) { if (this.stuff == null) this.stuff = "Threadsafe!"; } return this.stuff; } } public string AndNonsense { get { lock (Thing.padlock) { if (this.andNonsense == null) this.andNonsense = "Also threadsafe!"; } return this.andNonsense; } } // Rest of class... } In cases where the get operations are expensive and unrelated, a single locking object is unsuitable because a call to Stuff would block all calls to AndNonsense, degrading performance. And rather than create a lock object for each call, wouldn't it be better to acquire the lock on the member itself (assuming it is not something that implements SyncRoot or somesuch for that purpose? For example: public string Stuff { get { lock (this.stuff) { // Pretend that this is a very expensive operation. if (this.stuff == null) this.stuff = "Still threadsafe and good?"; } return this.stuff; } } Strangely, I have never seen this approach recommended or warned against. Am I missing something obvious?

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  • Can Haskell's monads be thought of as using and returning a hidden state parameter?

    - by AJM
    I don't understand the exact algebra and theory behind Haskell's monads. However, when I think about functional programming in general I get the impression that state would be modelled by taking an initial state and generating a copy of it to represent the next state. This is like when one list is appended to another; neither list gets modified, but a third list is created and returned. Is it therefore valid to think of monadic operations as implicitly taking an initial state object as a parameter and implicitly returning a final state object? These state objects would be hidden so that the programmer doesn't have to worry about them and to control how they gets accessed. So, the programmer would not try to copy the object representing the IO stream as it was ten minutes ago. In other words, if we have this code: main = do putStrLn "Enter your name:" name <- getLine putStrLn ( "Hello " ++ name ) ...is it OK to think of the IO monad and the "do" syntax as representing this style of code? putStrLn :: IOState -> String -> IOState getLine :: IOState -> (IOState, String) main :: IOState -> IOState -- main returns an IOState we can call "state3" main state0 = putStrLn state2 ("Hello " ++ name) where (state2, name) = getLine state1 state1 = putStrLn state0 "Enter your name:"

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  • Problems with Database Search Code (asp.net vb)

    - by Phil
    Here is a sample of my database search code: Dim sql As String = "Select * From Table Where " Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim andor As Boolean = AndOr1.SelectedValue 'selection can be AND or OR (0 / 1) 'Code for when the user selects AND If NameSearch.Text.ToString IsNot String.Empty And andor = 0 Then sql += "Surname LIKE '%" & name & "%' AND " End If If EmailSearch.Text.ToString IsNot String.Empty And andor = 0 Then sql += "Email LIKE '%" & email & "%' AND " End If If CitySearchBox.Text.ToString IsNot String.Empty And andor = 0 Then sql += "City LIKE '%" & city & "%' AND " End If 'Code for when the user selects OR If NameSearch.Text.ToString IsNot String.Empty And andor = 1 Then sql += "(Surname LIKE '%" & name & "%' OR " End If If EmailSearch.Text.ToString IsNot String.Empty And andor = 1 Then sql += "Email LIKE '%" & email & "%') OR " End If If CitySearchBox.Text.ToString IsNot String.Empty And andor = 1 Then sql += "(City LIKE '%" & city & "%' OR " End If sql = CleanString(sql) End Sub When the user selects AND (as andor.selectedvalue(0)) then the sql is produced fine like this; Select * From Table Where Surname LIKE '%test%' AND Email LIKE '%test%' AND City LIKE '%test%' But if the user selects OR (as andor.selectedvalue(1)), nothing is outputted except; Select * From Table Where Im sure the controls have values so are not string.empty and when the user selects OR the correct value 1 is being assigned to andor.

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  • Java string to double conversion.

    - by wretrOvian
    Hi, I've been reading up on the net about the issues with handling float and double types in java. Unfortunately, the image is still not clear. Hence, i'm asking here direct. :( My MySQL table has various DECIMAL(m,d) columns. The m may range from 5 to 30. d stays a constant at 2. Question 1. What equivalent data-type should i be using in Java to work (i.e store, retrieve, and process) with the size of the values in my table? (I've settled with double - hence this post). Question 2. While trying to parse a double from a string, i'm getting errors Double dpu = new Double(dpuField.getText()); for example - "1" -> java.lang.NumberFormatException: empty String "10" -> 1.0 "101" -> 10.0 "101." -> 101.0 "101.1" -> 101.0 "101.19" -> 101.1 What am i doing wrong? What is the correct way to convert a string to a double value? And what measures should i take to perform operations on such values?

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  • [Rails] checkbox to update attribute

    - by Jeff
    [Updated a bit] I have a Task model that has a :completed boolean attribute. If I click on it I want it to execute the 'finish' method. The main problem is that I am displays a series of checkboxes in a list and subsequent checkboxes after the first one are ignored. The method is never called for the given task/checkbox combo. I have this chunk of code in my view: <% current_user.tasks.each do |t|%> <% if t.completed == false %> <%= check_box_tag :completed, true, checked = false %> <%= observe_field :completed, :url => { :controller => 'tasks', :action => :finish , :id => t.id }, :frequency => 0.25, :update => :completed, :with => true %> and my finish method looks like this: def finish @task = Task.find(params[:id]) new = {:completed => true} @task.update_attributes(new) render :update do |page| page.replace_html "taskListing", :partial => 'home/task_listing' end

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  • How can several different datatypes be saved in one table

    - by poseidon
    This is my situation: I am constructing an ad-like application in Django and Mysql. I am using a flexible-ad approach where we have: a table with ad categories (several categories such as home, furniture, cars, etc.) id_category name a table with details for the ad categories (home: area, squared meters. car: seats, color.) id_detail id_category (the categ the detail describes) name type (boolean, char, int, long, etc.) the ad table (i am selling a house. i am selling a car.) id_ad id_category text date a table where i plan to consolidate the details of the ads (home: A-area, 500 sq-meters. car: 5 seats, red.) id_detail_ad id_ad id_detail value Is this possible? Can I have a table of details for all the ads, even if details include numbers, texts, booleans, etc? Or would I have to save them all as text and then interpret them via code accordingly? Please express your opinions. Thank you.

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  • grails question (sample 1 of Grails To Action book) problem with Controller and Service

    - by fegloff
    Hi, I'm doing Grails To Action sample for chapter one. Every was just fine until I started to work with Services. When I run the app I have the following error: groovy.lang.MissingPropertyException: No such property: quoteService for class: qotd.QuoteController at qotd.QuoteController$_closure3.doCall(QuoteController.groovy:14) at qotd.QuoteController$_closure3.doCall(QuoteController.groovy) at java.lang.Thread.run(Thread.java:619) Here is my groovie QuoteService class, which has an error within the definition of GetStaticQuote (ERROR: Groovy:unable to resolve class Quote) package qotd class QuoteService { boolean transactional = false def getRandomQuote() { def allQuotes = Quote.list() def randomQuote = null if (allQuotes.size() > 0) { def randomIdx = new Random().nextInt(allQuotes.size()) randomQuote = allQuotes[randomIdx] } else { randomQuote = getStaticQuote() } return randomQuote } def getStaticQuote() { return new Quote(author: "Anonymous",content: "Real Programmers Don't eat quiche") } } Controller groovie class package qotd class QuoteController { def index = { redirect(action: random) } def home = { render "<h1>Real Programmers do not each quiche!</h1>" } def random = { def randomQuote = quoteService.getRandomQuote() [ quote : randomQuote ] } def ajaxRandom = { def randomQuote = quoteService.getRandomQuote() render "<q>${randomQuote.content}</q>" + "<p>${randomQuote.author}</p>" } } Quote Class: package qotd class Quote { String content String author Date created = new Date() static constraints = { author(blank:false) content(maxSize:1000, blank:false) } } I'm doing the samples using Eclipse with grails addin. Any advice? Regards, Francisco

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  • Refactor link to show/hide a table row

    - by abatishchev
    I have a table with row which cab be hidden by user. It's implemented this way: Markup: <table> <tr> <td> <table style="margin-left: auto; text-align: right;"> <tr> <td class="stats-hide"> <a href="#" onclick="hideStats();">Hide</a> </td> <td class="stats-show" style="display: none;"> <a href="#" onclick="showStats();">Show</a> </td> </tr> </table> </td> </tr> <tr class="stats-hide"> <td> <!-- data --> </td> </tr> </table> And jQuery code: <script type="text/javascript" language="javascript"> function hideStats() { hideControls(true, $('.stats-hide')); hideControls(false, $('.stats-show')); } function showStats() { hideControls(false, $('.stats-hide')); hideControls(true, $('.stats-show')); } function hideControls(value, arr) { $(arr).each(function () { if (value) { $(this).hide(); } else { $(this).show(); } }); } </script> How to implement the same behavior with one, single link and one, probably, CSS class? My idea - store somewhere a boolean variable and toggle controls visibility relatively to this variable. Are there more?

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  • problem linking vba modules in MS Access 2007

    - by Ted
    I am upgrading a database system from Access 2000 db to Access 2007, which communicates with several chemistry measuring devices(pH meter, scale, etc) via an RS 232 serial port. The first db consists of several modules containing vba code that enables the communications with the ports, as well as supports the code behind the forms in the second db. The user, or lab tech, navigates through the forms in the second db to interact with the lab devices, and also to generate the reports which display the info. from the devices. The reports are also part of the second db. The code works in Access 2000, but once I convert it to 2007, the code in the second db cannot find the function calls in the first db that dictate the progression from screen to screen. I have tried importing the modules into the second db, and I have tried linking them, but it still doesn't work. The error message is #438: "Object doesn't support this property or method." Any suggestions would be greatly appreciated. Here is the code for the first function that is not being called correctly: Description: ' This routine is used to return to the calling form and close the active form. ' ' Input: ' strFormCalled --- the active form ' strCallingForm --- the form that called the active form ' blnUnhideOrOpen --- whether to open or just unhide form Public Sub basReturnToCallingForm(ByVal strFormCalled As String, ByVal _ strCallingForm As Variant, Optional blnUnhideOrOpen As Boolean = True) On Error GoTo err_basReturnToCaliingForm If Not basIsBlankString(strCallingForm) And blnUnhideOrOpen Then DoCmd.OpenForm strCallingForm, acNormal Else Call basUnHideForm(strCallingForm) End If Call basCloseForm(strFormCalled) exit_basReturnToCaliingForm: Exit Sub err_basReturnToCaliingForm: Err.Raise Err.Number, "basReturnToCaliingForm", Err.Description End Sub I will post the second function shortly, but I have to go to a meeting... The second funtion that isn't 'working' is a cmdStartClick that is supposed to be called when a user initializes a pump. However, within that function, it's also sticking on a line that is supposed to progress to the next form in the db. The other thing is that the code works in Access 2002, but not in Access 2007...

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  • TreeView update bug in the VB.NET

    - by CFP
    Consider the following code: Dim Working As Boolean = False Private Sub TreeView1_AfterCheck(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterCheck If Working Then Exit Sub Working = True e.Node.Checked = Not e.Node.Checked Working = False End Sub Private Sub TreeView1_MouseClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles TreeView1.MouseClick If e.Button = Windows.Forms.MouseButtons.Right Then MsgBox("Checked = " & TreeView1.SelectedNode.Checked) End Sub Where TreeView1 is a TreeView added to the form, with CheckBoxes set to true and one node added. The code basically cancel any node checking occuring on the form. Single-clicking the top node to check it works well : your click is immediately canceled. Yet if you double-click the checkbox, it will display a tick. But verifying the check state through a right click will yield a Checked = False dialog. How come? Is it a bug (I'm using the latest .Net Framework 4.0, and he same occurs in 2.0), or am I doing something wrong here? Is there a work around? Thanks! EDIT: Additionally, the MouseDoubleClick event is not raised before you click once again. EDIT 2: Posted a bug report at Microsoft Connect

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  • Trouble accessing data in relationships in Ember

    - by user3618430
    I'm having trouble saving data in this model relationship. My models are as follows: App.Flow = DS.Model.extend({ title: DS.attr('string'), content: DS.attr('string'), isCustom: DS.attr('boolean'), params: DS.hasMany('parameter', {async: true}) }); App.Parameter = DS.Model.extend({ flow: DS.belongsTo('flow'), param: DS.attr('string'), param_tooltip: DS.attr('string'), param_value: DS.attr('string') }); As you can see, I want Flows to have multiple Parameters. I have a rudimentary setup using Flow and Parameter fixtures, which behave as expected in the templates. However, when I try to create new ones in the controller, I have trouble setting the flow and parameter values correctly. var p = this.store.createRecord('parameter', { param: "foo", param_tooltip: "world", param_value: "hello" }); var f = this.store.createRecord('flow', { title: 'job', content: title, isCustom: true, params: [p] // doesn't seem to work }); f.set('params', [p]); // doesn't seem to work p.set('flow', f); // also doesn't seem to work // Save the new model p.save(); f.save(); I've tried a lot of solutions after staring at this and StackOverflow for a while (not just the ones listed). I'm not really sure what to try next. One thing that I noticed in the Ember inspector was that the ids of these created elements were not integers (they were something like the string 'fixture_0'), but I'm not really sure why that would be, whether its related, or how to fix it. Thanks!

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  • Very simple python functions takes spends long time in function and not subfunctions

    - by John Salvatier
    I have spent many hours trying to figure what is going on here. The function 'grad_logp' in the code below is called many times in my program, and cProfile and runsnakerun the visualize the results reveals that the function grad_logp spends about .00004s 'locally' every call not in any functions it calls and the function 'n' spends about .00006s locally every call. Together these two times make up about 30% of program time that I care about. It doesn't seem like this is function overhead as other python functions spend far less time 'locally' and merging 'grad_logp' and 'n' does not make my program faster, but the operations that these two functions do seem rather trivial. Does anyone have any suggestions on what might be happening? Have I done something obviously inefficient? Am I misunderstanding how cProfile works? def grad_logp(self, variable, calculation_set ): p = params(self.p,self.parents) return self.n(variable, self.p) def n (self, variable, p ): gradient = self.gg(variable, p) return np.reshape(gradient, np.shape(variable.value)) def gg(self, variable, p): if variable is self: gradient = self._grad_logps['x']( x = self.value, **p) else: gradient = __builtin__.sum([self._pgradient(variable, parameter, value, p) for parameter, value in self.parents.iteritems()]) return gradient

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  • Playing craps, asking and printing

    - by Angelo Mejia
    How do I ask the amount of games of craps someone wants to play and print the number of wins as a result of n number of games? Also How do I make a table in the main method using the previous methods I have? A table like this but shows the results: Percent Wins Games Experiment Number 1 2 3 4 5 6 7 8 9 10 100 1000 10000 100000 1000000 public class CrapsAnalysis { public static int rollDie( int n) { return (int)(Math.random()*n) + 1 ; } public static int rollDice( ) { int die1 ; int die2 ; die1 = rollDie(6) ; die2 = rollDie(6) ; return die1 + die2 ; } public static boolean playOneGame( ) { int newDice ; //repeated dice rolls int roll ; //first roll of the dice int playerPoint = 0 ; //player point if no win or loss on first roll newDice = rollDice() ; roll = rollDice() ; if (roll == 7 || roll == 11) return true; else if (roll == 2 || roll == 3 || roll == 12) return false; else { playerPoint = roll; newDice = rollDice(); do { newDice = rollDice(); } while (newDice != playerPoint || newDice != 7) ; if (newDice == 7) return false; else return true; } } public static int playGames ( int n ) { int numWon = 0; for (int i = 1; i <= n; i++) if(playOneGame()) numWon++; return numWon; } public static void main(String[] args) { //Don't know how to ask and print out the results of the number of wins depending on the n number of games played } }

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  • Analyzing an IronPython Scope

    - by Vercinegetorix
    I'm trying to write C# code with an embedded IronPython script. Then want to analyze the contents of the script, i.e. list all variables, functions, class and their members/methods. There's an easy way to start, assuming I've got a scope defined and code executed in it already: dynamic variables=pyScope.GetVariables(); foreach (string v in variables) { dynamic dynamicV=pyScope.GetVariable(); /*seems to return everything. variables, functions, classes, instances of classes*/ } But how do I figure out what the type of a variable is? For the following python 'objects', dynamicV.GetType() will return different values: x=5 --system.Int32 y="asdf" --system.String def func():... --IronPython.Runtime.PythonFunction z=class() -- IronPython.Runtime.Types.OldInstance, how can I identify what the actual python class is? class NewClass -- throws an error, GetType() is unavailable. This is almost what I'm looking for. I could capture the exception thrown when unavailable and assume it's a class declaration, but that seems unclean. Is there a better approach? To discover the members/methods of a class it looks like I can use: ObjectOperations op = pyEngine.Operations; object instance = op.Call("className"); foreach (string j in op.GetMemberNames("className")) { object member=op.GetMember(instance, j); Console.WriteLine(member.GetType()); /*once again, GetType() provides some info about the type of the member, but returns null sometimes*/ } Also, how do I get the parameters to a method? Thanks!

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  • A little confused about MVC and where to put a database query

    - by jax
    OK, so my Joomla app is in MVC format. I am still a little confused about where to put certain operations, in the Controller or in the Model. This function below is in the controller, it gets called when &task=remove. Should the database stuff be in the Model? It does not seem to fit there because I have two models editapp (display a single application) and allapps (display all the applications), now which one would I put the delete operation in? /** * Delete an application */ function remove() { global $mainframe; $cid = JRequest::getVar( 'cid', array(), '', 'array' ); $db =& JFactory::getDBO(); //if there are items to delete if(count($cid)){ $cids = implode( ',', $cid ); $query = "DELETE FROM #__myapp_apps WHERE id IN ( $cids )"; $db->setQuery( $query ); if (!$db->query()){ echo "<script> alert('".$db->getErrorMsg()."');window.history.go(-1); </script>\n"; } } $mainframe->redirect( 'index.php?option=' . $option . '&c=apps'); } I am also confused about how the flow works. For example, there is a display() function in the controller that gets called by default. If I pass a task, does the display() function still run or does it go directly to the function name passed by $task?

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