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• ASP.NET MVC–How to show asterisk after required field label

  - by DigiMortal

  Usually we have some required fields on our forms and it would be nice if ASP.NET MVC views can detect those fields automatically and display nice red asterisk after field label. As this functionality is not built in I built my own solution based on data annotations. In this posting I will show you how to show red asterisk after label of required fields. Here are the main information sources I used when working out my own solution: How can I modify LabelFor to display an asterisk on required fields? (stackoverflow) ASP.NET MVC – Display visual hints for the required fields in your model (Radu Enuca) Although my code was first written for completely different situation I needed it later and I modified it to work with models that use data annotations. If data member of model has Required attribute set then asterisk is rendered after field. If Required attribute is missing then there will be no asterisk. Here’s my code. You can take just LabelForRequired() methods and paste them to your own HTML extension class. public static class HtmlExtensions {     [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]     public static MvcHtmlString LabelForRequired<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, string labelText = "")     {         return LabelHelper(html,             ModelMetadata.FromLambdaExpression(expression, html.ViewData),             ExpressionHelper.GetExpressionText(expression), labelText);     }       private static MvcHtmlString LabelHelper(HtmlHelper html,         ModelMetadata metadata, string htmlFieldName, string labelText)     {         if (string.IsNullOrEmpty(labelText))         {             labelText = metadata.DisplayName ?? metadata.PropertyName ?? htmlFieldName.Split('.').Last();         }           if (string.IsNullOrEmpty(labelText))         {             return MvcHtmlString.Empty;         }           bool isRequired = false;           if (metadata.ContainerType != null)         {             isRequired = metadata.ContainerType.GetProperty(metadata.PropertyName)                             .GetCustomAttributes(typeof(RequiredAttribute), false)                             .Length == 1;         }           TagBuilder tag = new TagBuilder("label");         tag.Attributes.Add(             "for",             TagBuilder.CreateSanitizedId(                 html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(htmlFieldName)             )         );           if (isRequired)             tag.Attributes.Add("class", "label-required");           tag.SetInnerText(labelText);           var output = tag.ToString(TagRenderMode.Normal);             if (isRequired)         {             var asteriskTag = new TagBuilder("span");             asteriskTag.Attributes.Add("class", "required");             asteriskTag.SetInnerText("*");             output += asteriskTag.ToString(TagRenderMode.Normal);         }         return MvcHtmlString.Create(output);     } } And here’s how to use LabelForRequired extension method in your view: <div class="field">     @Html.LabelForRequired(m => m.Name)     @Html.TextBoxFor(m => m.Name)     @Html.ValidationMessageFor(m => m.Name) </div> After playing with CSS style called .required my example form looks like this: These red asterisks are not part of original view mark-up. LabelForRequired method detected that these properties have Required attribute set and rendered out asterisks after field names. NB! By default asterisks are not red. You have to define CSS class called “required” to modify how asterisk looks like and how it is positioned.

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• Given an XML which contains a representation of a graph, how to apply it DFS algorithm? [on hold]

  - by winston smith

  Given the followin XML which is a directed graph: <?xml version="1.0" encoding="iso-8859-1" ?> <!DOCTYPE graph PUBLIC "-//FC//DTD red//EN" "../dtd/graph.dtd"> <graph direct="1"> <vertex label="V0"/> <vertex label="V1"/> <vertex label="V2"/> <vertex label="V3"/> <vertex label="V4"/> <vertex label="V5"/> <edge source="V0" target="V1" weight="1"/> <edge source="V0" target="V4" weight="1"/> <edge source="V5" target="V2" weight="1"/> <edge source="V5" target="V4" weight="1"/> <edge source="V1" target="V2" weight="1"/> <edge source="V1" target="V3" weight="1"/> <edge source="V1" target="V4" weight="1"/> <edge source="V2" target="V3" weight="1"/> </graph> With this classes i parsed the graph and give it an adjacency list representation: import java.io.IOException; import java.util.HashSet; import java.util.LinkedList; import java.util.Collection; import java.util.Iterator; import java.util.logging.Level; import java.util.logging.Logger; import practica3.util.Disc; public class ParsingXML { public static void main(String[] args) { try { // TODO code application logic here Collection<Vertex> sources = new HashSet<Vertex>(); LinkedList<String> lines = Disc.readFile("xml/directed.xml"); for (String lin : lines) { int i = Disc.find(lin, "source=\""); String data = ""; if (i > 0 && i < lin.length()) { while (lin.charAt(i + 1) != '"') { data += lin.charAt(i + 1); i++; } Vertex v = new Vertex(); v.setName(data); v.setAdy(new HashSet<Vertex>()); sources.add(v); } } Iterator it = sources.iterator(); while (it.hasNext()) { Vertex ver = (Vertex) it.next(); Collection<Vertex> adyacencias = ver.getAdy(); LinkedList<String> ls = Disc.readFile("xml/graphs.xml"); for (String lin : ls) { int i = Disc.find(lin, "target=\""); String data = ""; if (lin.contains("source=\""+ver.getName())) { Vertex v = new Vertex(); if (i > 0 && i < lin.length()) { while (lin.charAt(i + 1) != '"') { data += lin.charAt(i + 1); i++; } v.setName(data); } i = Disc.find(lin, "weight=\""); data = ""; if (i > 0 && i < lin.length()) { while (lin.charAt(i + 1) != '"') { data += lin.charAt(i + 1); i++; } v.setWeight(Integer.parseInt(data)); } if (v.getName() != null) { adyacencias.add(v); } } } } for (Vertex vert : sources) { System.out.println(vert); System.out.println("adyacencias: " + vert.getAdy()); } } catch (IOException ex) { Logger.getLogger(ParsingXML.class.getName()).log(Level.SEVERE, null, ex); } } } This is another class: import java.util.Collection; import java.util.Objects; public class Vertex { private String name; private int weight; private Collection ady; public Collection getAdy() { return ady; } public void setAdy(Collection adyacencias) { this.ady = adyacencias; } public String getName() { return name; } public void setName(String nombre) { this.name = nombre; } public int getWeight() { return weight; } public void setWeight(int weight) { this.weight = weight; } @Override public int hashCode() { int hash = 7; hash = 43 * hash + Objects.hashCode(this.name); hash = 43 * hash + this.weight; return hash; } @Override public boolean equals(Object obj) { if (obj == null) { return false; } if (getClass() != obj.getClass()) { return false; } final Vertex other = (Vertex) obj; if (!Objects.equals(this.name, other.name)) { return false; } if (this.weight != other.weight) { return false; } return true; } @Override public String toString() { return "Vertice{" + "name=" + name + ", weight=" + weight + '}'; } } And finally: /** * * @author user */ /* -*-jde-*- */ /* <Disc.java> Contains the main argument*/ import java.io.*; import java.util.LinkedList; /** * Lectura y escritura de archivos en listas de cadenas * Ideal para el uso de las clases para gráficas. * * @author Peralta Santa Anna Victor Miguel * @since Julio 2011 */ public class Disc { /** * Metodo para lectura de un archivo * * @param fileName archivo que se va a leer * @return El archivo en representacion de lista de cadenas */ public static LinkedList<String> readFile(String fileName) throws IOException { BufferedReader file = new BufferedReader(new FileReader(fileName)); LinkedList<String> textlist = new LinkedList<String>(); while (file.ready()) { textlist.add(file.readLine().trim()); } file.close(); /* for(String linea:textlist){ if(linea.contains("source")){ //String generado = linea.replaceAll("<\\w+\\s+\"", ""); //System.out.println(generado); } }*/ return textlist; }//readFile public static int find(String linea,String palabra){ int i,j; boolean found = false; for(i=0,j=0;i<linea.length();i++){ if(linea.charAt(i)==palabra.charAt(j)){ j++; if(j==palabra.length()){ found = true; return i; } }else{ continue; } } if(!found){ i= -1; } return i; } /** * Metodo para la escritura de un archivo * * @param fileName archivo que se va a escribir * @param tofile la lista de cadenas que quedaran en el archivo * @param append el bit que dira si se anexa el contenido o se empieza de cero */ public static void writeFile(String fileName, LinkedList<String> tofile, boolean append) throws IOException { FileWriter file = new FileWriter(fileName, append); for (int i = 0; i < tofile.size(); i++) { file.write(tofile.get(i) + "\n"); } file.close(); }//writeFile /** * Metodo para escritura de un archivo * @param msg archivo que se va a escribir * @param tofile la cadena que quedaran en el archivo * @param append el bit que dira si se anexa el contenido o se empieza de cero */ public static void writeFile(String msg, String tofile, boolean append) throws IOException { FileWriter file = new FileWriter(msg, append); file.write(tofile); file.close(); }//writeFile }// I'm stuck on what can be the best way to given an adjacency list representation of the graph how to apply it Depth-first search algorithm. Any idea of how to aproach to complete the task?

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• android camera preview blank screen

  - by user1104836

  I want to capture a photo manually not by using existing camera apps. So i made this Activity: public class CameraActivity extends Activity { private Camera mCamera; private Preview mPreview; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_camera); // Create an instance of Camera // mCamera = Camera.open(0); // Create our Preview view and set it as the content of our activity. mPreview = new Preview(this); mPreview.safeCameraOpen(0); FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview); preview.addView(mPreview); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.activity_camera, menu); return true; } } This is the CameraPreview which i want to use: public class Preview extends ViewGroup implements SurfaceHolder.Callback { SurfaceView mSurfaceView; SurfaceHolder mHolder; //CAM INSTANCE ================================ private Camera mCamera; List<Size> mSupportedPreviewSizes; //============================================= /** * @param context */ public Preview(Context context) { super(context); mSurfaceView = new SurfaceView(context); addView(mSurfaceView); // Install a SurfaceHolder.Callback so we get notified when the // underlying surface is created and destroyed. mHolder = mSurfaceView.getHolder(); mHolder.addCallback(this); mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } /** * @param context * @param attrs */ public Preview(Context context, AttributeSet attrs) { super(context, attrs); // TODO Auto-generated constructor stub } /** * @param context * @param attrs * @param defStyle */ public Preview(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); // TODO Auto-generated constructor stub } /* (non-Javadoc) * @see android.view.ViewGroup#onLayout(boolean, int, int, int, int) */ @Override protected void onLayout(boolean arg0, int arg1, int arg2, int arg3, int arg4) { // TODO Auto-generated method stub } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { // Now that the size is known, set up the camera parameters and begin // the preview. Camera.Parameters parameters = mCamera.getParameters(); parameters.setPreviewSize(width, height); requestLayout(); mCamera.setParameters(parameters); /* Important: Call startPreview() to start updating the preview surface. Preview must be started before you can take a picture. */ mCamera.startPreview(); } @Override public void surfaceCreated(SurfaceHolder holder) { // TODO Auto-generated method stub } @Override public void surfaceDestroyed(SurfaceHolder holder) { // Surface will be destroyed when we return, so stop the preview. if (mCamera != null) { /* Call stopPreview() to stop updating the preview surface. */ mCamera.stopPreview(); } } /** * When this function returns, mCamera will be null. */ private void stopPreviewAndFreeCamera() { if (mCamera != null) { /* Call stopPreview() to stop updating the preview surface. */ mCamera.stopPreview(); /* Important: Call release() to release the camera for use by other applications. Applications should release the camera immediately in onPause() (and re-open() it in onResume()). */ mCamera.release(); mCamera = null; } } public void setCamera(Camera camera) { if (mCamera == camera) { return; } stopPreviewAndFreeCamera(); mCamera = camera; if (mCamera != null) { List<Size> localSizes = mCamera.getParameters().getSupportedPreviewSizes(); mSupportedPreviewSizes = localSizes; requestLayout(); try { mCamera.setPreviewDisplay(mHolder); } catch (IOException e) { e.printStackTrace(); } /* Important: Call startPreview() to start updating the preview surface. Preview must be started before you can take a picture. */ mCamera.startPreview(); } } public boolean safeCameraOpen(int id) { boolean qOpened = false; try { releaseCameraAndPreview(); mCamera = Camera.open(id); mCamera.startPreview(); qOpened = (mCamera != null); } catch (Exception e) { // Log.e(R.string.app_name, "failed to open Camera"); e.printStackTrace(); } return qOpened; } Camera.PictureCallback mPicCallback = new Camera.PictureCallback() { @Override public void onPictureTaken(byte[] data, Camera camera) { // TODO Auto-generated method stub Log.d("lala", "pic is taken"); } }; public void takePic() { mCamera.startPreview(); // mCamera.takePicture(null, mPicCallback, mPicCallback); } private void releaseCameraAndPreview() { this.setCamera(null); if (mCamera != null) { mCamera.release(); mCamera = null; } } } This is the Layout of CameraActivity: <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".CameraActivity" > <FrameLayout android:id="@+id/camera_preview" android:layout_width="0dip" android:layout_height="fill_parent" android:layout_weight="1" /> <Button android:id="@+id/button_capture" android:text="Capture" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" /> </LinearLayout> But when i start the CameraActivity, i just see a blank white background and the Capture-Button??? Why i dont see the Camera-Screen?

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• Turning on collision crashes game

  - by MomentumGaming

  I am getting a null pointer excecption to both my sprite and level. I am working on my mob class, and when I try to move him and the move function is called, the game crashes after checking collision with a null pointer excecption. Taking out the one line that actually checks if the tile located in front of it fixes the problem. Also, if i keep collision ON but don't move the position of the mob (the spider) the game works fine. I will have collision, and the spider appears on the screen, only problem is, getting it to move causes this nasty error that i just can't fix. true Exception in thread "Display" java.lang.NullPointerException at com.apcompsci.game.entity.mob.Mob.collision(Mob.java:67) at com.apcompsci.game.entity.mob.Mob.move(Mob.java:38) at com.apcompsci.game.entity.mob.spider.update(spider.java:58) at com.apcompsci.game.level.Level.update(Level.java:55) at com.apcompsci.game.Game.update(Game.java:128) at com.apcompsci.game.Game.run(Game.java:106) at java.lang.Thread.run(Unknown Source) Here is my renderMob mehtod: public void renderMob(int xp,int yp,Sprite sprite,int flip) { xp -= xOffset; yp-=yOffset; for(int y = 0; y<32; y++) { int ya = y + yp; int ys = y; if(flip == 2||flip == 3)ys = 31-y; for(int x = 0; x<32; x++) { int xa = x + xp; int xs = x; if(flip == 1||flip == 3)xs = 31-x; if(xa < -32 || xa >=width || ya<0||ya>=height) break; if(xa<0) xa =0; int col = sprite.pixels[xs+ys*32]; if(col!= 0x000000) pixels[xa+ya*width] = col; } } } My spider class which determines the sprite and where I control movement, also rendering the spider onto the screen, when I increment ya to move the sprite, I get the crash, but without ya++, it runs flawlessly with a spider sprite on screen: package com.apcompsci.game.entity.mob; import com.apcompsci.game.entity.mob.Mob.Direction; import com.apcompsci.game.graphics.Screen; import com.apcompsci.game.graphics.Sprite; import com.apcompsci.game.level.Level; public class spider extends Mob{ Direction dir; private Sprite sprite; private boolean walking; public spider(int x, int y) { this.x = x <<4; this.y = y <<4; sprite = sprite.spider_forward; } public void update() { int xa = 0, ya = 0; ya++; if(ya<0) { sprite = sprite.spider_forward; dir = Direction.UP; } if(ya>0) { sprite = sprite.spider_back; dir = Direction.DOWN; } if(xa<0) { sprite = sprite.spider_side; dir = Direction.LEFT; } if(xa>0) { sprite = sprite.spider_side; dir = Direction.LEFT; } if(xa!= 0 || ya!= 0) { System.out.println("true"); move(xa,ya); walking = true; } else{ walking = false; } } public void render(Screen screen) { screen.renderMob(x, y, sprite, 0); } } This is th mob class that contains the move() method that is called in the spider class above. This move method calls the collision method. tile and sprite comes up null in the debugger: package com.apcompsci.game.entity.mob; import java.util.ArrayList; import java.util.List; import com.apcompsci.game.entity.Entity; import com.apcompsci.game.entity.projectile.DemiGodProjectile; import com.apcompsci.game.entity.projectile.Projectile; import com.apcompsci.game.graphics.Sprite; public class Mob extends Entity{ protected Sprite sprite; protected boolean moving = false; protected enum Direction { UP,DOWN,LEFT,RIGHT } protected Direction dir; public void move(int xa,int ya) { if(xa != 0 && ya != 0) { move(xa,0); move(0,ya); return; } if(xa>0) dir = Direction.RIGHT; if(xa<0) dir = Direction.LEFT; if(ya>0)dir = Direction.DOWN; if(ya<0)dir = Direction.UP; if(!collision(xa,ya)){ x+= xa; y+=ya; } } public void update() { } public void shoot(int x, int y, double dir) { //dir = Math.toDegrees(dir); Projectile p = new DemiGodProjectile(x, y,dir); level.addProjectile(p); } public boolean collision(int xa,int ya) { boolean solid = false; for(int c = 0; c<4; c++) { int xt = ((x+xa) + c % 2 * 14 - 8 )/16; int yt = ((y+ya) + c / 2 * 12 +3 )/16; if(level.getTile(xt, yt).solid()) solid = true; } return solid; } public void render() { } } Finally, here is the method in which i call the add() method for the spider to add it to the level: protected void loadLevel(String path) { try{ BufferedImage image = ImageIO.read(SpawnLevel.class.getResource(path)); int w = width =image.getWidth(); int h = height = image.getHeight(); tiles = new int[w*h]; image.getRGB(0, 0, w,h, tiles,0, w); } catch(IOException e){ e.printStackTrace(); System.out.println("Exception! Could not load level file!"); } add(new spider(20,45)); } I don't think i need to include the level class but just in case, I have provided a gistHub link for better context. It contains all of the full classes listed above , plus my entity class and maybe another. Thanks for the help if you decide to do so, much appreciated! Also, please tell me if i'm in the wrong section of stackeoverflow, i figured that since this is the gamign section that it belonged but debugging code normally goes into the general section.

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• How do encrypt a long or int using the Bouncy Castle crypto routines for BlackBerry?

  - by DanG

  How do encrypt/decrypt a long or int using the Bouncy Castle crypto routines for BlackBerry? I know how to encrypt/decrypt a String. I can encrypt a long but can't get a long to decrypt properly. Some of this is poorly done, but I'm just trying stuff out at the moment. I've included my entire crypto engine here: import org.bouncycastle.crypto.BufferedBlockCipher; import org.bouncycastle.crypto.DataLengthException; import org.bouncycastle.crypto.InvalidCipherTextException; import org.bouncycastle.crypto.engines.AESFastEngine; import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher; import org.bouncycastle.crypto.params.KeyParameter; public class CryptoEngine { // Global Variables // Global Objects private static AESFastEngine engine; private static BufferedBlockCipher cipher; private static KeyParameter key; public static boolean setEncryptionKey(String keyText) { // adding in spaces to force a proper key keyText += " "; // cutting off at 128 bits (16 characters) keyText = keyText.substring(0, 16); keyText = HelperMethods.cleanUpNullString(keyText); byte[] keyBytes = keyText.getBytes(); key = new KeyParameter(keyBytes); engine = new AESFastEngine(); cipher = new PaddedBufferedBlockCipher(engine); // just for now return true; } public static String encryptString(String plainText) { try { byte[] plainArray = plainText.getBytes(); cipher.init(true, key); byte[] cipherBytes = new byte[cipher.getOutputSize(plainArray.length)]; int cipherLength = cipher.processBytes(plainArray, 0, plainArray.length, cipherBytes, 0); cipher.doFinal(cipherBytes, cipherLength); String cipherString = new String(cipherBytes); return cipherString; } catch (DataLengthException e) { Logger.logToConsole(e); } catch (IllegalArgumentException e) { Logger.logToConsole(e); } catch (IllegalStateException e) { Logger.logToConsole(e); } catch (InvalidCipherTextException e) { Logger.logToConsole(e); } catch (Exception ex) { Logger.logToConsole(ex); } // else return "";// default bad value } public static String decryptString(String encryptedText) { try { byte[] cipherBytes = encryptedText.getBytes(); cipher.init(false, key); byte[] decryptedBytes = new byte[cipher.getOutputSize(cipherBytes.length)]; int decryptedLength = cipher.processBytes(cipherBytes, 0, cipherBytes.length, decryptedBytes, 0); cipher.doFinal(decryptedBytes, decryptedLength); String decryptedString = new String(decryptedBytes); // crop accordingly int index = decryptedString.indexOf("\u0000"); if (index >= 0) { decryptedString = decryptedString.substring(0, index); } return decryptedString; } catch (DataLengthException e) { Logger.logToConsole(e); } catch (IllegalArgumentException e) { Logger.logToConsole(e); } catch (IllegalStateException e) { Logger.logToConsole(e); } catch (InvalidCipherTextException e) { Logger.logToConsole(e); } catch (Exception ex) { Logger.logToConsole(ex); } // else return "";// default bad value } private static byte[] convertLongToByteArray(long longToConvert) { return new byte[] { (byte) (longToConvert >>> 56), (byte) (longToConvert >>> 48), (byte) (longToConvert >>> 40), (byte) (longToConvert >>> 32), (byte) (longToConvert >>> 24), (byte) (longToConvert >>> 16), (byte) (longToConvert >>> 8), (byte) (longToConvert) }; } private static long convertByteArrayToLong(byte[] byteArrayToConvert) { long returnable = 0; for (int counter = 0; counter < byteArrayToConvert.length; counter++) { returnable += ((byteArrayToConvert[byteArrayToConvert.length - counter - 1] & 0xFF) << counter * 8); } if (returnable < 0) { returnable++; } return returnable; } public static long encryptLong(long plainLong) { try { String plainString = String.valueOf(plainLong); String cipherString = encryptString(plainString); byte[] cipherBytes = cipherString.getBytes(); long returnable = convertByteArrayToLong(cipherBytes); return returnable; } catch (Exception e) { Logger.logToConsole(e); } // else return Integer.MIN_VALUE;// default bad value } public static long decryptLong(long encryptedLong) { byte[] cipherBytes = convertLongToByteArray(encryptedLong); cipher.init(false, key); byte[] decryptedBytes = new byte[cipher.getOutputSize(cipherBytes.length)]; int decryptedLength = cipherBytes.length; try { cipher.doFinal(decryptedBytes, decryptedLength); } catch (DataLengthException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IllegalStateException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (InvalidCipherTextException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } long plainLong = convertByteArrayToLong(decryptedBytes); return plainLong; } public static boolean encryptBoolean(int plainBoolean) { return false; } public static boolean decryptBoolean(int encryptedBoolean) { return false; } public static boolean testLongToByteArrayConversion() { boolean returnable = true; // fails out of the bounds of an integer, the conversion to long from byte // array does not hold, need to figure out a better solution for (long counter = -1000000; counter < 1000000; counter++) { long test = counter; byte[] bytes = convertLongToByteArray(test); long result = convertByteArrayToLong(bytes); if (result != test) { returnable = false; Logger.logToConsole("long conversion failed"); Logger.logToConsole("test = " + test + "\n result = " + result); } // regardless } // the end Logger.logToConsole("final returnable result = " + returnable); return returnable; } }

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• We've completed the first iteration

  - by CliveT

  There are a lot of features in C# that are implemented by the compiler and not by the underlying platform. One such feature is a lambda expression. Since local variables cannot be accessed once the current method activation finishes, the compiler has to go out of its way to generate a new class which acts as a home for any variable whose lifetime needs to be extended past the activation of the procedure. Take the following example:     Random generator = new Random();     Func func = () = generator.Next(10); In this case, the compiler generates a new class called c_DisplayClass1 which is marked with the CompilerGenerated attribute. [CompilerGenerated] private sealed class c__DisplayClass1 {     // Fields     public Random generator;     // Methods     public int b__0()     {         return this.generator.Next(10);     } } Two quick comments on this: (i)    A display was the means that compilers for languages like Algol recorded the various lexical contours of the nested procedure activations on the stack. I imagine that this is what has led to the name. (ii)    It is a shame that the same attribute is used to mark all compiler generated classes as it makes it hard to figure out what they are being used for. Indeed, you could imagine optimisations that the runtime could perform if it knew that classes corresponded to certain high level concepts. We can see that the local variable generator has been turned into a field in the class, and the body of the lambda expression has been turned into a method of the new class. The code that builds the Func object simply constructs an instance of this class and initialises the fields to their initial values.     c__DisplayClass1 class2 = new c__DisplayClass1();     class2.generator = new Random();     Func func = new Func(class2.b__0); Reflector already contains code to spot this pattern of code and reproduce the form containing the lambda expression, so this is example is correctly decompiled. The use of compiler generated code is even more spectacular in the case of iterators. C# introduced the idea of a method that could automatically store its state between calls, so that it can pick up where it left off. The code can express the logical flow with yield return and yield break denoting places where the method should return a particular value and be prepared to resume.         {             yield return 1;             yield return 2;             yield return 3;         } Of course, there was already a .NET pattern for expressing the idea of returning a sequence of values with the computation proceeding lazily (in the sense that the work for the next value is executed on demand). This is expressed by the IEnumerable interface with its Current property for fetching the current value and the MoveNext method for forcing the computation of the next value. The sequence is terminated when this method returns false. The C# compiler links these two ideas together so that an IEnumerator returning method using the yield keyword causes the compiler to produce the implementation of an Iterator. Take the following piece of code.         IEnumerable GetItems()         {             yield return 1;             yield return 2;             yield return 3;         } The compiler implements this by defining a new class that implements a state machine. This has an integer state that records which yield point we should go to if we are resumed. It also has a field that records the Current value of the enumerator and a field for recording the thread. This latter value is used for optimising the creation of iterator instances. [CompilerGenerated] private sealed class d__0 : IEnumerable, IEnumerable, IEnumerator, IEnumerator, IDisposable {     // Fields     private int 1__state;     private int 2__current;     public Program 4__this;     private int l__initialThreadId; The body gets converted into the code to construct and initialize this new class. private IEnumerable GetItems() {     d__0 d__ = new d__0(-2);     d__.4__this = this;     return d__; } When the class is constructed we set the state, which was passed through as -2 and the current thread. public d__0(int 1__state) {     this.1__state = 1__state;     this.l__initialThreadId = Thread.CurrentThread.ManagedThreadId; } The state needs to be set to 0 to represent a valid enumerator and this is done in the GetEnumerator method which optimises for the usual case where the returned enumerator is only used once. IEnumerator IEnumerable.GetEnumerator() {     if ((Thread.CurrentThread.ManagedThreadId == this.l__initialThreadId)               && (this.1__state == -2))     {         this.1__state = 0;         return this;     } The state machine itself is implemented inside the MoveNext method. private bool MoveNext() {     switch (this.1__state)     {         case 0:             this.1__state = -1;             this.2__current = 1;             this.1__state = 1;             return true;         case 1:             this.1__state = -1;             this.2__current = 2;             this.1__state = 2;             return true;         case 2:             this.1__state = -1;             this.2__current = 3;             this.1__state = 3;             return true;         case 3:             this.1__state = -1;             break;     }     return false; } At each stage, the current value of the state is used to determine how far we got, and then we generate the next value which we return after recording the next state. Finally we return false from the MoveNext to signify the end of the sequence. Of course, that example was really simple. The original method body didn't have any local variables. Any local variables need to live between the calls to MoveNext and so they need to be transformed into fields in much the same way that we did in the case of the lambda expression. More complicated MoveNext methods are required to deal with resources that need to be disposed when the iterator finishes, and sometimes the compiler uses a temporary variable to hold the return value. Why all of this explanation? We've implemented the de-compilation of iterators in the current EAP version of Reflector (7). This contrasts with previous version where all you could do was look at the MoveNext method and try to figure out the control flow. There's a fair amount of things we have to do. We have to spot the use of a CompilerGenerated class which implements the Enumerator pattern. We need to go to the class and figure out the fields corresponding to the local variables. We then need to go to the MoveNext method and try to break it into the various possible states and spot the state transitions. We can then take these pieces and put them back together into an object model that uses yield return to show the transition points. After that Reflector can carry on optimising using its usual optimisations. The pattern matching is currently a little too sensitive to changes in the code generation, and we only do a limited analysis of the MoveNext method to determine use of the compiler generated fields. In some ways, it is a pity that iterators are compiled away and there is no metadata that reflects the original intent. Without it, we are always going to dependent on our knowledge of the compiler's implementation. For example, we have noticed that the Async CTP changes the way that iterators are code generated, so we'll have to do some more work to support that. However, with that warning in place, we seem to do a reasonable job of decompiling the iterators that are built into the framework. Hopefully, the EAP will give us a chance to find examples where we don't spot the pattern correctly or regenerate the wrong code, and we can improve things. Please give it a go, and report any problems.

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• Execution plan warnings–The final chapter

  - by Dave Ballantyne

  In my previous posts (here and here), I showed examples of some of the execution plan warnings that have been added to SQL Server 2012.  There is one other warning that is of interest to me : “Unmatched Indexes”. Firstly, how do I know this is the final one ?  The plan is an XML document, right ? So that means that it can have an accompanying XSD.  As an XSD is a schema definition, we can poke around inside it to find interesting things that *could* be in the final XML file. The showplan schema is stored in the folder Microsoft SQL Server\110\Tools\Binn\schemas\sqlserver\2004\07\showplan and by comparing schemas over releases you can get a really good idea of any new functionality that has been added. Here is the section of the Sql Server 2012 showplan schema that has been interesting me so far : <xsd:complexType name="AffectingConvertWarningType"> <xsd:annotation> <xsd:documentation>Warning information for plan-affecting type conversion</xsd:documentation> </xsd:annotation> <xsd:sequence> <!-- Additional information may go here when available --> </xsd:sequence> <xsd:attribute name="ConvertIssue" use="required"> <xsd:simpleType> <xsd:restriction base="xsd:string"> <xsd:enumeration value="Cardinality Estimate" /> <xsd:enumeration value="Seek Plan" /> <!-- to be extended here --> </xsd:restriction> </xsd:simpleType> </xsd:attribute> <xsd:attribute name="Expression" type ="xsd:string" use="required" /></xsd:complexType><xsd:complexType name="WarningsType"> <xsd:annotation> <xsd:documentation>List of all possible iterator or query specific warnings (e.g. hash spilling, no join predicate)</xsd:documentation> </xsd:annotation> <xsd:choice minOccurs="1" maxOccurs="unbounded"> <xsd:element name="ColumnsWithNoStatistics" type="shp:ColumnReferenceListType" minOccurs="0" maxOccurs="1" /> <xsd:element name="SpillToTempDb" type="shp:SpillToTempDbType" minOccurs="0" maxOccurs="unbounded" /> <xsd:element name="Wait" type="shp:WaitWarningType" minOccurs="0" maxOccurs="unbounded" /> <xsd:element name="PlanAffectingConvert" type="shp:AffectingConvertWarningType" minOccurs="0" maxOccurs="unbounded" /> </xsd:choice> <xsd:attribute name="NoJoinPredicate" type="xsd:boolean" use="optional" /> <xsd:attribute name="SpatialGuess" type="xsd:boolean" use="optional" /> <xsd:attribute name="UnmatchedIndexes" type="xsd:boolean" use="optional" /> <xsd:attribute name="FullUpdateForOnlineIndexBuild" type="xsd:boolean" use="optional" /></xsd:complexType> I especially like the “to be extended here” comment,  high hopes that we will see more of these in the future.   So “Unmatched Indexes” was a warning that I couldn’t get and many thanks must go to Fabiano Amorim (b|t) for showing me the way.   Filtered indexes were introduced in Sql Server 2008 and are really useful if you only need to index only a portion of the data within a table.  However,  if your SQL code uses a variable as a predicate on the filtered data that matches the filtered condition, then the filtered index cannot be used as, naturally,  the value in the variable may ( and probably will ) change and therefore will need to read data outside the index.  As an aside,  you could use option(recompile) here , in which case the optimizer will build a plan specific to the variable values and use the filtered index,  but that can bring about other problems.   To demonstrate this warning, we need to generate some test data :   DROP TABLE #TestTab1GOCREATE TABLE #TestTab1 (Col1 Int not null, Col2 Char(7500) not null, Quantity Int not null)GOINSERT INTO #TestTab1 VALUES (1,1,1),(1,2,5),(1,2,10),(1,3,20), (2,1,101),(2,2,105),(2,2,110),(2,3,120)GO and then add a filtered index CREATE INDEX ixFilter ON #TestTab1 (Col1)WHERE Quantity = 122 Now if we execute SELECT COUNT(*) FROM #TestTab1 WHERE Quantity = 122 We will see the filtered index being scanned But if we parameterize the query DECLARE @i INT = 122SELECT COUNT(*) FROM #TestTab1 WHERE Quantity = @i The plan is very different a table scan, as the value of the variable used in the predicate can change at run time, and also we see the familiar warning triangle. If we now look at the properties pane, we will see two pieces of information “Warnings” and “UnmatchedIndexes”. So, handily, we are being told which filtered index is not being used due to parameterization.

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• Java style FOR loop in a clojure interpeter ?

  - by Kevin

  I have a basic interpreter in clojure. Now i need to implement for (initialisation; finish-test; loop-update) { statements } inside my interpreter. I will attach my interpreter code I got so far. Any help is appreciated. Interpreter (declare interpret make-env) ;; (def do-trace false) ;; ;; simple utilities (def third ; return third item in a list (fn [a-list] (second (rest a-list)))) (def fourth ; return fourth item in a list (fn [a-list] (third (rest a-list)))) (def run ; make it easy to test the interpreter (fn [e] (println "Processing: " e) (println "=> " (interpret e (make-env))))) ;; for the environment (def make-env (fn [] '())) (def add-var (fn [env var val] (cons (list var val) env))) (def lookup-var (fn [env var] (cond (empty? env) 'error (= (first (first env)) var) (second (first env)) :else (lookup-var (rest env) var)))) ;; -- define numbers (def is-number? (fn [expn] (number? expn))) (def interpret-number (fn [expn env] expn)) ;; -- define symbols (def is-symbol? (fn [expn] (symbol? expn))) (def interpret-symbol (fn [expn env] (lookup-var env expn))) ;; -- define boolean (def is-boolean? (fn [expn] (or (= expn 'true) (= expn 'false)))) (def interpret-boolean (fn [expn env] expn)) ;; -- define functions (def is-function? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'lambda (first expn))))) (def interpret-function (fn [expn env] expn)) ;; -- define addition (def is-plus? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '+ (first expn))))) (def interpret-plus (fn [expn env] (+ (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define subtraction (def is-minus? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '- (first expn))))) (def interpret-minus (fn [expn env] (- (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define multiplication (def is-times? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '* (first expn))))) (def interpret-times (fn [expn env] (* (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define division (def is-divides? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '/ (first expn))))) (def interpret-divides (fn [expn env] (/ (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define equals test (def is-equals? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '= (first expn))))) (def interpret-equals (fn [expn env] (= (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define greater-than test (def is-greater-than? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '> (first expn))))) (def interpret-greater-than (fn [expn env] (> (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define not (def is-not? (fn [expn] (and (list? expn) (= 2 (count expn)) (= 'not (first expn))))) (def interpret-not (fn [expn env] (not (interpret (second expn) env)))) ;; -- define or (def is-or? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'or (first expn))))) (def interpret-or (fn [expn env] (or (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define and (def is-and? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'and (first expn))))) (def interpret-and (fn [expn env] (and (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define with (def is-with? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'with (first expn))))) (def interpret-with (fn [expn env] (interpret (third expn) (add-var env (first (second expn)) (interpret (second (second expn)) env))))) ;; -- define if (def is-if? (fn [expn] (and (list? expn) (= 4 (count expn)) (= 'if (first expn))))) (def interpret-if (fn [expn env] (cond (interpret (second expn) env) (interpret (third expn) env) :else (interpret (fourth expn) env)))) ;; -- define function-application (def is-function-application? (fn [expn env] (and (list? expn) (= 2 (count expn)) (is-function? (interpret (first expn) env))))) (def interpret-function-application (fn [expn env] (let [function (interpret (first expn) env)] (interpret (third function) (add-var env (first (second function)) (interpret (second expn) env)))))) ;; the interpreter itself (def interpret (fn [expn env] (cond do-trace (println "Interpret is processing: " expn)) (cond ; basic values (is-number? expn) (interpret-number expn env) (is-symbol? expn) (interpret-symbol expn env) (is-boolean? expn) (interpret-boolean expn env) (is-function? expn) (interpret-function expn env) ; built-in functions (is-plus? expn) (interpret-plus expn env) (is-minus? expn) (interpret-minus expn env) (is-times? expn) (interpret-times expn env) (is-divides? expn) (interpret-divides expn env) (is-equals? expn) (interpret-equals expn env) (is-greater-than? expn) (interpret-greater-than expn env) (is-not? expn) (interpret-not expn env) (is-or? expn) (interpret-or expn env) (is-and? expn) (interpret-and expn env) ; special syntax (is-with? expn) (interpret-with expn env) (is-if? expn) (interpret-if expn env) ; functions (is-function-application? expn env) (interpret-function-application expn env) :else 'error)))

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• Oracle B2B - Synchronous Request Reply

  - by cdwright

  Introduction So first off, let me say I didn't create this demo (although I did modify it some). I got it from a member of the B2B development technical staff. Since it came with only a simple readme file, I thought I would take some time and write a more detailed explanation about how it works. Beginning with Oracle SOA Suite PS5 (11.1.1.6), B2B supports synchronous request reply over http using the b2b/syncreceiver servlet. I’m attaching the demo to this blog which includes a SOA composite archive that needs to be deployed using JDeveloper, a B2B repository with two agreements that need to be deployed using the B2B console, and a test xml file that gets sent to the b2b/syncreceiver servlet using your favorite SOAP test tool (I'm using Firefox Poster here). You can download the zip file containing the demo here. The demo works by sending the sample xml request file (req.xml) to http://<b2bhost>:8001/b2b/syncreceiver using the SOAP test tool.  The syncreceiver servlet keeps the socket connection open between itself and the test tool so that it can synchronously send the reply message back. When B2B receives the inbound request message, it is passed to the SOA composite through the default B2B Fabric binding. A simple reply is created in BPEL and returned to B2B which then sends the message back to the test tool using that same socket connection. I’ll show you the B2B configuration first, then we’ll look at the soa composite. Configuring B2B No additional configuration necessary in order to use the syncreceiver servlet. It is already running when you start SOA. After importing the GC_SyncReqRep.zip repository file into B2B, you’ll have the typical GlobalChips host trading partner and the Acme remote trading partner. Document Management The repository contains two very simple custom XML document definitions called Orders and OrdersResponse. In order to determine the trading partner agreement needed to process the inbound Orders document, you need to know two things about it; what is it and where it came from. So let’s look at how B2B identifies the appropriate document definition for the message. The XSD’s for these two document definitions themselves are not particularly interesting. Whenever you're dealing with custom XML documents, B2B identifies the appropriate document definition for each XML message using an XPath Identification Expression. The expression is entered for each of these document definitions under the document administration tab in the B2B console. The full XPATH expression for the Orders document is  //*[local-name()='shiporder']/*[local-name()='shipto']/*[local-name()='name']/text(). You can see this path in the XSD diagram below and how it uniquely identifies this message. The OrdersReponse document is identified in the same way. The XPath expression for it is //*[local-name()='Response']/*[local-name()='Status']/text(). You can see how it’s path differs uniquely identifying the reply from the request. Trading Partner Profile The trading partner profiles are very simple too. For GlobalChips, a generic identifier is being used to identify the sender of the response document using the host trading partner name. For Acme, a generic identifier is also being used to identify the sender of the inbound request using the remote trading partner name. The document types are added for the remote trading partner as usual. So the remote trading partner Acme is the sender of the Orders document, and it is the receiver of the OrdersResponse document. For the remote trading partner only, there needs to be a dummy channel which gets used in the outbound response agreement. The channel is not actually used. It is just a necessary place holder that needs to be there when creating the agreement. Trading Partner Agreement The agreements are equally simple. There is no validation and translation is not an option for a custom XML document type. For the InboundAgreement (request) the document definition is set to OrdersDef. In the Agreement Parameters section the generic identifiers have been added for the host and remote trading partners. That’s all that is needed for the inbound transaction. For the OutboundAgreement (response), the document definition is set to OrdersResponseDef and the generic identifiers for the two trading partners are added. The remote trading partner dummy delivery channel is also added to the agreement. SOA Composite Import the SOA composite archive into JDeveloper as an EJB JAR file. Open the composite and you should have a project that looks like this. In the composite, open the b2bInboundSyncSvc exposed service and advance through the setup wizard. Select your Application Server Connection and advance to the Operations window. Notice here that the B2B binding is set to Receive. It is not set for Synchronous Request Reply. Continue advancing through the wizard as you normally would and select finish at the end. Now open BPELProcess1 in the composite. The BPEL process is set as a Synchronous Request Reply as you can see below. The while loop is there just to give the process something to do. The actual reply message is prepared in the assignResponseValues assignment followed by an Invoke of the B2B binding. Open the replyResponse Invoke and go to the properties tab. You’ll see that the fromTradingPartnerId, toTradingPartner, documentTypeName, and documentProtocolRevision properties have been set. Testing the Configuration To test the configuration, I used Firefox Poster. Enter the URL for the b2b/syncreceiver servlet and browse for the req.xml file that contains the test request message. In the Headers tab, add the property ‘from’ and give it the value ‘Acme’. This is how B2B will know where the message is coming from and it will use that information along with the document type name to find the right trading partner agreement. Now post the message. You should get back a response with a status of ‘200 OK’. That’s all there is to it.

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• Chart Filtering

  - by Tim Dexter

  Interesting question from a colleague this week. Can you add a filter to a chart to just show a specific set of data? In an RTF template, you need to do a little finagling in the chart definition. In an online template, a couple of clicks and you're done. RTF Build your chart as you would normally to include all the data to start with. Now flip to the Advanced tab to see the code behind the chart. Its not very pretty but with a little effort you can get it looking a little more friendly. Here's my chart showing employees and their salaries. <Graph depthAngle="50" depthRadius="8" seriesEffect="SE_AUTO_GRADIENT"> <LegendArea visible="true"/>  <Title text="Executive Department Only" visible="true" horizontalAlignment="CENTER"/>  <LocalGridData colCount="{count(.//G_2)}" rowCount="1">   <RowLabels>    <Label>SALARY</Label>   </RowLabels>   <ColLabels>    <xsl:for-each select=".//G_2">     <Label><xsl:value-of select="EMP_NAME"/></Label>    </xsl:for-each>   </ColLabels>   <DataValues>    <RowData>     <xsl:for-each select=".//G_2">      <Cell><xsl:value-of select="SALARY"/></Cell>     </xsl:for-each>    </RowData>   </DataValues>  </LocalGridData> </Graph> Note the emboldened text. Its currently grabbing all values in the G_2 level of the data. We can use an XPATH expression to filter the data to the set we want to see. In my case I want to only see the employees that are in the Executive department. My  data is structured thus:   <DATA_DS>     <G_1>         <DEPARTMENT_NAME>Accounting</DEPARTMENT_NAME>         <G_2>             <MANAGER>Higgins</MANAGER>             <EMPLOYEE_ID>206</EMPLOYEE_ID>             <HIRE_DATE>2002-06-07T00:00:00.000-04:00</HIRE_DATE>             <SALARY>8300</SALARY>             <JOB_TITLE>Public Accountant</JOB_TITLE>             <PARAS>11000</PARAS>             <EMP_NAME>William Gietz</EMP_NAME>         </G_2> So the XPATH expression Im going to use to limit the data to the Executive department would be .//G_2[../DEPARTMENT_NAME='Executive'] Note the ../ moves the parser up the XML tree to be able to test the DEPARTMENT_NAME value. I added this XPATH expression to the three instances that need it ColCount, ColLabels and RowData. Its simple enough to do. Testing your XPATH expression is easier to do using a table of data. Please note, as soon as you make changes to the chart code. Going back to the Builder tab, you'll find that everything is grayed out. I recommend you make all the changes you can via the chart dialog before updating the code. Online Template Implementing the filter is much simpler, there is a dialog box to help you out. Add you chart and fill out the various data points you want to show. then hit the Filter item in the ribbon above the chart. That will pop the filter dialog box where you can then add a filter to the chart.   You can add multiple filters if needed and of course you can use the Manage Filters button to re-open and edit the filters. Pretty straightforward stuff!

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• Couldn't match expected type - Haskell Code

  - by wvyar

  I'm trying to learn Haskell, but the small bit of sample code I tried to write is running into a fairly large amount of "Couldn't match expected type" errors. Can anyone give me some guidance as to what I'm doing wrong/how I should go about this? These are the errors, but I'm not really sure how I should be writing my code. toDoSchedulerSimple.hs:6:14: Couldn't match expected type `[t0]' with actual type `IO String' In the return type of a call of `readFile' In a stmt of a 'do' block: f <- readFile inFile In the expression: do { f <- readFile inFile; lines f } toDoSchedulerSimple.hs:27:9: Couldn't match expected type `[a0]' with actual type `IO ()' In the return type of a call of `putStr' In a stmt of a 'do' block: putStr "Enter task name: " In the expression: do { putStr "Enter task name: "; task <- getLine; return inFileArray : task } toDoSchedulerSimple.hs:34:9: Couldn't match expected type `IO ()' with actual type `[a0]' In a stmt of a 'do' block: putStrLn "Your task is: " ++ (inFileArray !! i) In the expression: do { i <- randomRIO (0, (length inFileArray - 1)); putStrLn "Your task is: " ++ (inFileArray !! i) } In an equation for `getTask': getTask inFileArray = do { i <- randomRIO (0, (length inFileArray - 1)); putStrLn "Your task is: " ++ (inFileArray !! i) } toDoSchedulerSimple.hs:41:9: Couldn't match expected type `[a0]' with actual type `IO ()' In the return type of a call of `putStr' In a stmt of a 'do' block: putStr "Enter the task you would like to end: " In the expression: do { putStr "Enter the task you would like to end: "; task <- getLine; filter (endTaskCheck task) inFileArray } toDoSchedulerSimple.hs:60:53: Couldn't match expected type `IO ()' with actual type `[String] -> IO ()' In a stmt of a 'do' block: schedulerSimpleMain In the expression: do { (getTask inFileArray); schedulerSimpleMain } In a case alternative: "get-task" -> do { (getTask inFileArray); schedulerSimpleMain } This is the code itself. I think it's fairly straightforward, but the idea is to run a loop, take input, and perform actions based off of it by calling other functions. import System.Random (randomRIO) import Data.List (lines) initializeFile :: [char] -> [String] initializeFile inFile = do f <- readFile inFile let parsedFile = lines f return parsedFile displayHelp :: IO() displayHelp = do putStrLn "Welcome to To Do Scheduler Simple, written in Haskell." putStrLn "Here are some commands you might find useful:" putStrLn " 'help' : Display this menu." putStrLn " 'quit' : Exit the program." putStrLn " 'new-task' : Create a new task." putStrLn " 'get-task' : Randomly select a task." putStrLn " 'end-task' : Mark a task as finished." putStrLn " 'view-tasks' : View all of your tasks." quit :: IO() quit = do putStrLn "We're very sad to see you go...:(" putStrLn "Come back soon!" createTask :: [String] -> [String] createTask inFileArray = do putStr "Enter task name: " task <- getLine return inFileArray:task getTask :: [String] -> IO() getTask inFileArray = do i <- randomRIO (0, (length inFileArray - 1)) putStrLn "Your task is: " ++ (inFileArray !! i) endTaskCheck :: String -> String -> Bool endTaskCheck str1 str2 = str1 /= str2 endTask :: [String] -> [String] endTask inFileArray = do putStr "Enter the task you would like to end: " task <- getLine return filter (endTaskCheck task) inFileArray viewTasks :: [String] -> IO() viewTasks inFileArray = case inFileArray of [] -> do putStrLn "\nEnd of tasks." _ -> do putStrLn (head inFileArray) viewTasks (tail inFileArray) schedulerSimpleMain :: [String] -> IO() schedulerSimpleMain inFileArray = do putStr "SchedulerSimple> " input <- getLine case input of "help" -> displayHelp "quit" -> quit "new-task" -> schedulerSimpleMain (createTask inFileArray) "get-task" -> do (getTask inFileArray); schedulerSimpleMain "end-task" -> schedulerSimpleMain (endTask inFileArray) "view-tasks" -> do (viewTasks inFileArray); schedulerSimpleMain _ -> do putStrLn "Invalid input."; schedulerSimpleMain main :: IO() main = do putStr "What is the name of the schedule? " sName <- getLine schedulerSimpleMain (initializeFile sName) Thanks, and apologies if this isn't the correct place to be asking such a question.

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• Silverlight Cream for March 23, 2010 -- #818

  - by Dave Campbell

  In this Issue: Max Paulousky, Jeremy Likness, Mark Tucker, Christian Schormann, Page Brooks, Brad Abrams(-2-), Jeff Wilcox, Unnir, Bea Stollnitz, John Papa and Adam Kinney, and Bill Reiss(-2-). Shoutouts: Ashish Shetty posted his material from his MIX10 presentation: Stepping outside the browser with Silverlight 4 Not Silverlight, but dang useful, Karl Shifflett posted a Visual Studio 2010 XAML Editor IntelliSense Presenter Extension Yavor Georgiev posted his MIX10 material: Two samples from today's MIX talk From SilverlightCream.com: GroupBox Sketching Control for WPF applications Using Blend Max Paulousky creates a GroupBox control for SketchFlow for WPF. He includes a link to an example of doing the same for Silverlight. Sequential Asynchronous Workflows in Silverlight using Coroutines Jeremy Likness' latest post begann with a post on the Silverlight.net forum and Rob Eisenburg's MVVM presentation from MIX10 resulting in the use of Wintellect's PowerThreading library (downloadable), and Coroutines. Windows Phone 7 UI Templates Mark Tucker has been putting a lot of thought into WP7 apps and produced 5 templates for building apps, downloadable in PowerPoint format. He's also looking to discuss this concept. Blend 4: About Path Layout, Part I Christian Schormann has a great tutorial up about Expression Blend 4 and path layout ... this is lots of great info, and it's only part 1! Custom Splash Screen for Windows Phone Page Brooks makes very quick work of showing how to add a splash screen to your WP7 app... very nice, Page! Silverlight 4 + RIA Services - Ready for Business: Exposing Data from Entity Framework Brad Abrams next post in the series is is on pulling your data from wherever it lives, and uses a DomainService to shape it for your Silverlight app. Silverlight 4 + RIA Services - Ready for Business: Consuming Data in the Silverlight Client Brad Abrams then discusses consuming that data in a Silverlight app. Not much code involvement at all.. great ROI :) Building Silverlight 3 and Silverlight 4 applications on a .NET 3.5 build machine Jeff Wilcox talks about building Silverlight 3 and Silverlight 4B both on a .NET 3.5 machine. He then adds in the Toolkit, and even WCF RIA Services. Expression Blend 4 - XAML generation tweaks Unnir demonstrates a few changes to Expression Blend 4 that produce more compact XAML. He's also asking for other examples you'd like to see tightened up. How can I sort a hierarchy? Bea Stollnitz posts plausible solutions to sorting data items at each level of a hierarchical UI, with descriptions of why they don't work, followed by the real deal... Silverlight and WPF. Silverlight Training Course (Silverlight 4) John Papa and Adam Kinney have posted a huge body of work to get us up-to-speed on Silverlight 4 -- a WhitePaper, hands-on labs, and an 8-unit course with 25 accompanying videos... geez... Silverlight game development on Windows Phone 7 Bill Reiss has a post up discussing game development on WP7 in general and then discusses his SilverSprite library, with a link to it. XNA or Silverlight for Windows Phone 7 game development? Bill Reiss next discusses the advantage of using Silverlight or XNA for your WP7 game development, and who better to discuss both? Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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• Silverlight Cream for June 08, 2010 -- #877

  - by Dave Campbell

  In this Issue: Miroslav Miroslavov, Chris Klug, Beau, Christian Schormann(-2-), Dan Wahlin, Pete Brown, Michael S. Scherotter, Philipp Sumi, Andy Wigley, and Phil Middlemiss. Shoutouts: Mark Tucker set about learning Caliburn, and in the process is writing a Caliburn Book: Chapters 1-3 Jesse Liberty has a great link-laden post up about why we should all be learning/using Blend: Why Developers Should, Must, Do Care About The New Expression Blend be sure to read what he says about WP7 development, however! Charlie Kindel announced an Install problem with the Developer Tools CTP Refresh and the WP7 tools... check this out if you're having problems. John Papa has a good post up on the happenings yesterday: Expression Studio 4 Launch of Blend, SketchFlow, Encoder and More! Erik Mork & Company's latest "This Week in Silverlight" is titled First Drop: Prism v4 – First Drop is Available From SilverlightCream.com: Animated navigation between Pages Miroslav Miroslavov has Part 8 of his "Silverlight in Action" series up, detailing cool things from the CompleteIT site... this one is on Animated navigation between pages. Subtitling videos Chris Klug got a gig adding subtitles to videos for Microsoft (sweet) ... and no, not *that* kind of subtitles... read how he approached the final solution. Silverlight Watermark TextBox I'm not sure we can have too many Watermark TextBoxes, and neither does Beau , who sent me a link to this one... give it a dance and decide. Blend 4: Collaborative SketchFlow Feedback with SharePoint With the new Blend release, Christian Schormann has a post up describing the lashup to Sharepoint for sharing Sketchflow and getting feedback. New Utility, Links, and Tutorials for Path-Based Layout Christian Schormann also has a collection of resources for Path-Based Layouts, including a utility "that lets you apply a whole bunch of position-specific effects without having to write any code"... lots of links to resources here. Tales from the Trenches – Building a Real-World Silverlight Line of Business Application Dan Wahlin draws on his recent experience and lays out some of the fun and pitfalls of building LOB apps in Silverlight... WCF, MVVM, slides, and code included WPF (and Silverlight): Choose your Fonts and Text Rendering Options Wisely Pete Brown has a great post up on using fonts wisely across multiple platforms... lots of info and good discussion in the comments as well. Ball Watch USA Remember the awesome watch Michael S. Scherotter did in Silverlight 1 and then converted to Updated Ball Trainmaster Cannonball Watch to Silverlight 2? Well... there's now a contest underfoot and 8 videos to help you get started... all good stuff, and good luck! ... Michael has a post up about the contest: Enter to Win a Ball Watch by Creating One in Silverlight Announcing Sketchables – Rapid Mockup Creation with SketchFlow By way of Jesse Libertyhttp://jesseliberty.com/2010/06/08/why-developers-should-must-do-care-about-the-new-expression-blend/, this is a cool production by Philipp Sumi about a simple mockup framework he's created. Perst - a database for Windows Phone 7 Silverlight I think one of my first comments to Michael Washington back at the MVP Summit 2010 was that we'd need a database engine, and too cool, but we've got one, Andy Wigley discusses Perst in this post... to save you some time, here's the Perst site A Chrome and Glass Theme - Part 7 Phil Middlemiss has part 7 of his great theme-building series up... this time he's giving the accordian control a once-over. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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• SQL SERVER – Quiz and Video – Introduction to Hierarchical Query using a Recursive CTE

  - by pinaldave

  This blog post is inspired from SQL Queries Joes 2 Pros: SQL Query Techniques For Microsoft SQL Server 2008 – SQL Exam Prep Series 70-433 – Volume 2.[Amazon] | [Flipkart] | [Kindle] | [IndiaPlaza] This is follow up blog post of my earlier blog post on the same subject - SQL SERVER – Introduction to Hierarchical Query using a Recursive CTE – A Primer. In the article we discussed various basics terminology of the CTE. The article further covers following important concepts of common table expression. What is a Common Table Expression (CTE) Building a Recursive CTE Identify the Anchor and Recursive Query Add the Anchor and Recursive query to a CTE Add an expression to track hierarchical level Add a self-referencing INNER JOIN statement Above six are the most important concepts related to CTE and SQL Server.  There are many more things one has to learn but without beginners fundamentals one can’t learn the advanced  concepts. Let us have small quiz and check how many of you get the fundamentals right. Quiz 1) You have an employee table with the following data. EmpID FirstName LastName MgrID 1 David Kennson 11 2 Eric Bender 11 3 Lisa Kendall 4 4 David Lonning 11 5 John Marshbank 4 6 James Newton 3 7 Sally Smith NULL You need to write a recursive CTE that shows the EmpID, FirstName, LastName, MgrID, and employee level. The CEO should be listed at Level 1. All people who work for the CEO will be listed at Level 2. All of the people who work for those people will be listed at Level 3. Which CTE code will achieve this result? WITH EmpList AS (SELECT Boss.EmpID, Boss.FName, Boss.LName, Boss.MgrID, 1 AS Lvl FROM Employee AS Boss WHERE Boss.MgrID IS NULL UNION ALL SELECT E.EmpID, E.FirstName, E.LastName, E.MgrID, EmpList.Lvl + 1 FROM Employee AS E INNER JOIN EmpList ON E.MgrID = EmpList.EmpID) SELECT * FROM EmpList WITH EmpListAS (SELECT EmpID, FirstName, LastName, MgrID, 1 as Lvl FROM Employee WHERE MgrID IS NULL UNION ALL SELECT EmpID, FirstName, LastName, MgrID, 2 as Lvl ) SELECT * FROM BossList WITH EmpList AS (SELECT EmpID, FirstName, LastName, MgrID, 1 as Lvl FROM Employee WHERE MgrID is NOT NULL UNION SELECT EmpID, FirstName, LastName, MgrID, BossList.Lvl + 1 FROM Employee INNER JOIN EmpList BossList ON Employee.MgrID = BossList.EmpID) SELECT * FROM EmpList 2) You have a table named Employee. The EmployeeID of each employee’s manager is in the ManagerID column. You need to write a recursive query that produces a list of employees and their manager. The query must also include the employee’s level in the hierarchy. You write the following code segment: WITH EmployeeList (EmployeeID, FullName, ManagerName, Level) AS ( –PICK ANSWER CODE HERE ) SELECT EmployeeID, FullName, ” AS [ManagerID], 1 AS [Level] FROM Employee WHERE ManagerID IS NULL UNION ALL SELECT emp.EmployeeID, emp.FullName mgr.FullName, 1 + 1 AS [Level] FROM Employee emp JOIN Employee mgr ON emp.ManagerID = mgr.EmployeeId SELECT EmployeeID, FullName, ” AS [ManagerID], 1 AS [Level] FROM Employee WHERE ManagerID IS NULL UNION ALL SELECT emp.EmployeeID, emp.FullName, mgr.FullName, mgr.Level + 1 FROM EmployeeList mgr JOIN Employee emp ON emp.ManagerID = mgr.EmployeeId Now make sure that you write down all the answers on the piece of paper. Watch following video and read earlier article over here. If you want to change the answer you still have chance. Solution 1) 1 2) 2 Now compare let us check the answers and compare your answers to following answers. I am very confident you will get them correct. Available at USA: Amazon India: Flipkart | IndiaPlaza Volume: 1, 2, 3, 4, 5 Please leave your feedback in the comment area for the quiz and video. Did you know all the answers of the quiz? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Silverlight Cream for June 01, 2010 -- #874

  - by Dave Campbell

  In this Issue: Michael Washington, Alan Beasley and Michael Washington, Miroslav Miroslavov, Max Paulousky, Teresa and Ronald Burger, Laurent Duveau, Tim Heuer, Jeff Brand, Mike Snow, and John Papa. Shoutouts: To pay homage to the Advanced Options button in Expression Blend, Adam Kinney posted: Expression Blend Advanced Options square wallpaper SilverLaw stood his drag and drop ripple on it's head for this one: Silver Soccer - A Case Study for the Flexible Surface Effect (Silverlight 4) From SilverlightCream.com: Expression Blend DataStore - A Powerful Tool For Designers Michael Washington dug into the documentation and with some Microsoft assistance has figured out how to use the SetDataStoreAction in SketchFlow... good tutorial and a game to demonstrate it's use. Windows Phone 7 View Model Style Video Player Alan Beasley and Michael Washington teamed up again to produce a ViewModel-Style Video Player for WP7 ... very nice interface I might add... very detailed tutorial and all the code... oh, and did you notice it uses MVVMLight... on WP7? ... just thought I'd mention that :) Navigation in 3D world of 2D objects In part 7 of the CompleteIT code explenation, Miroslav Miroslavov is discussing some of the very cool animation they did... 3D, moving camera... cool stuff! Search Engine Optimization (SEO) for Silverlight Applications. Part 2 Max Paulousky has part 2 of his Silverlight 4 and SEO series up. In part 2 he's discussing sitemaps and html content providing. He also has good links showing where to submit your sitemaps and information. Mousin’ down the PathListBox Teresa and Ronald Burger (not sure which) has a post up about the PathListBox and how they drew the path that they ended up using, and the code used to enable animation. Dynamically apply and change Theme with the Silverlight Toolkit We've all had fun playing with themes, but Laurent Duveau has an example up of letting your users change the theme at run-time. Microsoft Translator client library for Silverlight Tim Heuer has been playing with the Microsoft Translator for Silverlight and he has a "Works on My Machine" license on what he's making available .. but considering his access to resources... I'd say go for it :) Custom Per-Page Transitions in Windows Phone 7 Jeff Brand has a follow-on to his other WP7 post about page transitions and is now discussing per-page transitions Silverlight Tip of the Day #26 – Changing the Startup Class Mike Snow's latest 'tip' is a little more involved than a tip ... changing the startup class and actually removing (in his example), the page and app classes... code and xaml! I've seen this before but never explained as clean... fun stuff. Behaviors in Blend 4 (Silverlight TV #30) Episode 30 of Silverlight TV (now a tag at Silverlight Cream) finds John Papa talking to Adam Kinney about Behaviors in Blend 4... not only using them but creating a custom one. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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• SSIS Technique to Remove/Skip Trailer and/or Bad Data Row in a Flat File

  - by Compudicted

  I noticed that the question on how to skip or bypass a trailer record or a badly formatted/empty row in a SSIS package keeps coming back on the MSDN SSIS Forum. I tried to figure out the reason why and after an extensive search inside the forum and outside it on the entire Web (using several search engines) I indeed found that it seems even thought there is a number of posts and articles on the topic none of them are employing the simplest and the most efficient technique. When I say efficient I mean the shortest time to solution for the fellow developers. OK, enough talk. Let’s face the problem: Typically a flat file (e.g. a comma delimited/CSV) needs to be processed (loaded into a database in most cases really). Oftentimes, such an input file is produced by some sort of an out of control, 3-rd party solution and would come in with some garbage characters and/or even malformed/miss-formatted rows. One such example could be this imaginary file: As you can see several rows have no data and there is an occasional garbage character (1, in this example on row #7). Our task is to produce a clean file that will only capture the meaningful data rows. As an aside, our output/target may be a database table, but for the purpose of this exercise we will simply re-format the source. Let’s outline our course of action to start off: Will use SSIS 2005 to create a DFT; The DFT will use a Flat File Source to our input [bad] flat file; We will use a Conditional Split to process the bad input file; and finally Dump the resulting data to a new [clean] file. Well, only four steps, let’s see if it is too much of work. 1: Start the BIDS and add a DFT to the Control Flow designer (I named it Process Dirty File DFT): 2, and 3: I had added the data viewer to just see what I am getting, alas, surprisingly the data issues were not seen it:   What really is the key in the approach it is to properly set the Conditional Split Transformation. Visually it is: and specifically its SSIS Expression LEN([After CS Column 0]) > 1 The point is to employ the right Boolean expression (yes, the Conditional Split accepts only Boolean conditions). For the sake of this post I re-named the Output Name “No Empty Rows”, but by default it will be named Case 1 (remember to drag your first column into the expression area)! You can close your Conditional Split now. The next part will be crucial – consuming the output of our Conditional Split. Last step - #4: Add a Flat File Destination or any other one you need. Click on the Conditional Split and choose the green arrow to drop onto the target. When you do so make sure you choose the No Empty Rows output and NOT the Conditional Split Default Output. Make the necessary mappings. At this point your package must look like: As the last step will run our package to examine the produced output file. F5: and… it looks great!

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• Simple MVVM Walkthrough – Refactored

  - by Sean Feldman

  JR has put together a good introduction post into MVVM pattern. I love kick start examples that serve the purpose well. And even more than that I love examples that also can pass the real world projects check. So I took the sample code and refactored it slightly for a few aspects that a lot of developers might raise a brow. Michael has mentioned model (entity) visibility from view. I agree on that. A few other items that don’t settle are using property names as string (magical strings) and Saver class internal casting of a parameter (custom code for each Saver command). Fixing a property names usage is a straight forward exercise – leverage expressions. Something simple like this would do the initial job: class PropertyOf<T> { public static string Resolve(Expression<Func<T, object>> expression) { var member = expression.Body as MemberExpression; return member.Member.Name; } } With this, refactoring of properties names becomes an easy task, with confidence that an old property name string will not get left behind. An updated Invoice would look like this: public class Invoice : INotifyPropertyChanged { private int id; private string receiver; public event PropertyChangedEventHandler PropertyChanged; private void OnPropertyChanged(string propertyName) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } public int Id { get { return id; } set { if (id != value) { id = value; OnPropertyChanged(PropertyOf<Invoice>.Resolve(x => x.Id)); } } } public string Receiver { get { return receiver; } set { receiver = value; OnPropertyChanged(PropertyOf<Invoice>.Resolve(x => x.Receiver)); } } } For the saver, I decided to change it a little so now it becomes a “view-model agnostic” command, one that can be used for multiple commands/view-models. Updated Saver code now accepts an action at construction time and executes that action. No more black magic internal class Command : ICommand { private readonly Action executeAction; public Command(Action executeAction) { this.executeAction = executeAction; } public bool CanExecute(object parameter) { return true; } public event EventHandler CanExecuteChanged; public void Execute(object parameter) { // no more black magic executeAction(); } } Change in InvoiceViewModel is instantiation of Saver command and execution action for the specific command. public ICommand SaveCommand { get { if (saveCommand == null) saveCommand = new Command(ExecuteAction); return saveCommand; } set { saveCommand = value; } } private void ExecuteAction() { DisplayMessage = string.Format("Thanks for creating invoice: {0} {1}", Invoice.Id, Invoice.Receiver); } This way internal knowledge of InvoiceViewModel remains in InvoiceViewModel and Command (ex-Saver) is view-model agnostic. Now the sample is not only a good introduction, but also has some practicality in it. My 5 cents on the subject. Sample code MvvmSimple2.zip

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• Sitting Pretty

  - by Phil Factor

  Guest Editorial for Simple-Talk IT Pro newsletter'DBAs and SysAdmins generally prefer an expression of calmness under adversity. It is a subtle trick, and requires practice in front of a mirror to get it just right. Too much adversity and they think you're not coping; too much calmness and they think you're under-employed' I dislike the term 'avatar', when used to describe a portrait photograph. An avatar, in the sense of a picture, is merely the depiction of one's role-play alter-ego, often a ridiculous bronze-age deity. However, professional image is important. The choice and creation of online photos has an effect on the way your message is received and it is important to get that right. It is fine to use that photo of you after ten lagers on holiday in an Ibiza nightclub, but what works on Facebook looks hilarious on LinkedIn. My splendid photograph that I use online was done by a professional photographer at great expense and I've never had the slightest twinge of regret when I remember how much I paid for it. It is me, but a more pensive and dignified edition, oozing trust and wisdom. One gasps at the magical skill that a professional photographer can conjure up, without digital manipulation, to make the best of a derisory noggin (ed: slang for a head). Even if he had offered to depict me as a semi-naked, muscle-bound, sword-wielding hero, I'd have demurred. No, any professional person needs a carefully cultivated image that looks right. I'd never thought of using that profile shot, though I couldn't help noticing the photographer flinch slightly when he first caught sight of my face. There is a problem with using an avatar. The use of a single image doesn't express the appropriate emotion. At the moment, it is weird to see someone with a laughing portrait writing something solemn. A neutral cast to the face, somewhat like a passport photo, is probably the best compromise. Actually, the same is true of a working life in IT. One of the first skills I learned was not to laugh at managers, but, instead, to develop a facial expression that promoted a sense of keenness, energy and respect. Every profession has its own preferred facial cast. A neighbour of mine has the natural gift of a face that displays barely repressed grief. Though he is characteristically cheerful, he earns a remarkable income as a pallbearer. DBAs and SysAdmins generally prefer an expression of calmness under adversity. It is a subtle trick, and requires practice in front of a mirror to get it just right. Too much adversity and they think you're not coping; too much calmness and they think you're under-employed. With an appropriate avatar, you could do away with a lot of the need for 'smilies' to give clues as to the meaning of what you've written on forums and blogs. If you had a set of avatars, showing the full gamut of human emotions expressible in writing: Rage, fear, reproach, joy, ebullience, apprehension, exasperation, dissembly, irony, pathos, euphoria, remorse and so on. It would be quite a drop-down list on forums, but given the vast prairies of space on the average hard drive, who cares? It would cut down on the number of spats in Forums just as long as one picks the right avatar. As an unreconstructed geek, I find it hard to admit to the value of image in the workplace, but it is true. Just as we use professionals to tidy up and order our CVs and job applications, we should employ experts to enhance our professional image. After all you don't perform surgery or dentistry on yourself do you?

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• NHibernate Pitfalls: Custom Types and Detecting Changes

  - by Ricardo Peres

  This is part of a series of posts about NHibernate Pitfalls. See the entire collection here. NHibernate supports the declaration of properties of user-defined types, that is, not entities, collections or primitive types. These are used for mapping a database columns, of any type, into a different type, which may not even be an entity; think, for example, of a custom user type that converts a BLOB column into an Image. User types must implement interface NHibernate.UserTypes.IUserType. This interface specifies an Equals method that is used for comparing two instances of the user type. If this method returns false, the entity is marked as dirty, and, when the session is flushed, will trigger an UPDATE. So, in your custom user type, you must implement this carefully so that it is not mistakenly considered changed. For example, you can cache the original column value inside of it, and compare it with the one in the other instance. Let’s see an example implementation of a custom user type that converts a Byte[] from a BLOB column into an Image: 1: [Serializable] 2: public sealed class ImageUserType : IUserType 3: { 4: private Byte[] data = null; 5: 6: public ImageUserType() 7: { 8: this.ImageFormat = ImageFormat.Png; 9: } 10: 11: public ImageFormat ImageFormat 12: { 13: get; 14: set; 15: } 16: 17: public Boolean IsMutable 18: { 19: get 20: { 21: return (true); 22: } 23: } 24: 25: public Object Assemble(Object cached, Object owner) 26: { 27: return (cached); 28: } 29: 30: public Object DeepCopy(Object value) 31: { 32: return (value); 33: } 34: 35: public Object Disassemble(Object value) 36: { 37: return (value); 38: } 39: 40: public new Boolean Equals(Object x, Object y) 41: { 42: return (Object.Equals(x, y)); 43: } 44: 45: public Int32 GetHashCode(Object x) 46: { 47: return ((x != null) ? x.GetHashCode() : 0); 48: } 49: 50: public override Int32 GetHashCode() 51: { 52: return ((this.data != null) ? this.data.GetHashCode() : 0); 53: } 54: 55: public override Boolean Equals(Object obj) 56: { 57: ImageUserType other = obj as ImageUserType; 58: 59: if (other == null) 60: { 61: return (false); 62: } 63: 64: if (Object.ReferenceEquals(this, other) == true) 65: { 66: return (true); 67: } 68: 69: return (this.data.SequenceEqual(other.data)); 70: } 71: 72: public Object NullSafeGet(IDataReader rs, String[] names, Object owner) 73: { 74: Int32 index = rs.GetOrdinal(names[0]); 75: Byte[] data = rs.GetValue(index) as Byte[]; 76: 77: this.data = data as Byte[]; 78: 79: if (data == null) 80: { 81: return (null); 82: } 83: 84: using (MemoryStream stream = new MemoryStream(this.data ?? new Byte[0])) 85: { 86: return (Image.FromStream(stream)); 87: } 88: } 89: 90: public void NullSafeSet(IDbCommand cmd, Object value, Int32 index) 91: { 92: if (value != null) 93: { 94: Image data = value as Image; 95: 96: using (MemoryStream stream = new MemoryStream()) 97: { 98: data.Save(stream, this.ImageFormat); 99: value = stream.ToArray(); 100: } 101: } 102: 103: (cmd.Parameters[index] as DbParameter).Value = value ?? DBNull.Value; 104: } 105: 106: public Object Replace(Object original, Object target, Object owner) 107: { 108: return (original); 109: } 110: 111: public Type ReturnedType 112: { 113: get 114: { 115: return (typeof(Image)); 116: } 117: } 118: 119: public SqlType[] SqlTypes 120: { 121: get 122: { 123: return (new SqlType[] { new SqlType(DbType.Binary) }); 124: } 125: } 126: } In this case, we need to cache the original Byte[] data because it’s not easy to compare two Image instances, unless, of course, they are the same.

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• Introduction to WebCenter Personalization: &ldquo;The Conductor&rdquo;

  - by Steve Pepper

  There are some new faces in the town of WebCenter with the latest 11g PS3 release.  A new component has introduced itself as "Oracle WebCenter Personalization", a.k.a WCP, to simplify delivery of a personalized experience and content to end users.  This posting reviews one of the primary components within WCP: "The Conductor". The Conductor: This ain't just an ordinary cloud... One of the founding principals behind WebCenter Personalization was to provide an open client-side API that remains independent of the technology invoking it, in addition to independence from the architecture running it.  The Conductor delivers this, and much, much more. The Conductor is the engine behind WebCenter Personalization that allows flow-based documents, called "Scenarios", to be managed and executed on the server-side through a well published and RESTful api.      The Conductor also supports an extensible model for custom provider integration that can be easily invoked within a Scenario to promote seamless integration with existing business assets. Introducing the Scenario Conductor Scenarios are declarative offline-authored documents using the custom Personalization JDeveloper bundle included with WebCenter.  A Scenario contains one (or more) statements that can: Create variables that are scoped to the current execution context Iterate over collections, or loop until a specific condition is met Execute one or more statements when a condition is met Invoke other scenarios that exist within the same namespace Invoke a data provider that integrates with custom applications Once a variable is assigned within the Scenario's execution context, it can be referenced anywhere within the same Scenario using the common Expression Language syntax used in J2EE web containers. Scenarios are then published and tested to the Integrated WebLogic Server domain, or published remotely to other domains running WebCenter Personalization. Various Client-side Models The Conductor server API is built upon RESTful services that support a wide variety of clients able to communicate over HTTP.  The Conductor supports the following client-side models: REST:  Popular browser-based languages can be used to manage and execute Conductor Scenarios.  There are other public methods to retrieve configured provider metadata that can be used by custom applications. The Conductor currently supports XML and JSON for it's API syntax. Java: WebCenter Personalization delivers a robust and light-weight java client with the popular Jersey framework as it's foundation.  It has never been easier to write a remote java client to manage remote RESTful services. Expression Language (EL): Allow the results of Scenario execution to control your user interface or embed personalized content using the session-scoped managed bean.  The EL client can also be used in straight JSP pages with minimal configuration. Extensible Provider Framework The Conductor supports a pluggable provider framework for integrating custom code with Scenario execution.  There are two types of providers supported by the Conductor: Function Provider: Function Providers are simple java annotated classes with static methods that are meant to be served as utilities.  Some common uses would include: object creation or instantiation, data transformation, and the like.  Function Providers can be invoked using the common EL syntax from variable assignments, conditions, and loops. For example:  ${myUtilityClass:doStuff(arg1,arg2))} If you are familiar with EL Functions, Function Providers are based on the same concept. Data Provider: Like Function Providers, Data Providers are annotated java classes, but they must adhere to a much more strict object model.  Data Providers have access to a wealth of Conductor services, such as: Access to namespace-scoped configuration API that can be managed by Oracle Enterprise Manager, Scenario execution context for expression resolution, and more.  Oracle ships with three out-of-the-box data providers that supports integration with: Standardized Content Servers(CMIS),  Federated Profile Properties through the Properties Service, and WebCenter Activity Graph. Useful References If you are looking to immediately get started writing your own application using WebCenter Personalization Services, you will find the following references helpful in getting you on your way: Personalizing WebCenter Applications Authoring Personalized Scenarios in JDeveloper Using Personalization APIs Externally Implementing and Calling Function Providers Implementing and Calling Data Providers

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• Why is x=x++ undefined?

  - by ugoren

  It's undefined because the it modifies x twice between sequence points. The standard says it's undefined, therefore it's undefined. That much I know. But why? My understanding is that forbidding this allows compilers to optimize better. This could have made sense when C was invented, but now seems like a weak argument. If we were to reinvent C today, would we do it this way, or can it be done better? Or maybe there's a deeper problem, that makes it hard to define consistent rules for such expressions, so it's best to forbid them? So suppose we were to reinvent C today. I'd like to suggest simple rules for expressions such as x=x++, which seem to me to work better than the existing rules. I'd like to get your opinion on the suggested rules compared to the existing ones, or other suggestions. Suggested Rules: Between sequence points, order of evaluation is unspecified. Side effects take place immediately. There's no undefined behavior involved. Expressions evaluate to this value or that, but surely won't format your hard disk (strangely, I've never seen an implementation where x=x++ formats the hard disk). Example Expressions x=x++ - Well defined, doesn't change x. First, x is incremented (immediately when x++ is evaluated), then it's old value is stored in x. x++ + ++x - Increments x twice, evaluates to 2*x+2. Though either side may be evaluated first, the result is either x + (x+2) (left side first) or (x+1) + (x+1) (right side first). x = x + (x=3) - Unspecified, x set to either x+3 or 6. If the right side is evaluated first, it's x+3. It's also possible that x=3 is evaluated first, so it's 3+3. In either case, the x=3 assignment happens immediately when x=3 is evaluated, so the value stored is overwritten by the other assignment. x+=(x=3) - Well defined, sets x to 6. You could argue that this is just shorthand for the expression above. But I'd say that += must be executed after x=3, and not in two parts (read x, evaluate x=3, add and store new value). What's the Advantage? Some comments raised this good point. It's not that I'm after the pleasure of using x=x++ in my code. It's a strange and misleading expression. What I want is to be able to understand complicated expressions. Normally, a complicated expression is no more than the sum of its parts. If you understand the parts and the operators combining them, you can understand the whole. C's current behavior seems to deviate from this principle. One assignment plus another assignment suddenly doesn't make two assignments. Today, when I look at x=x++, I can't say what it does. With my suggested rules, I can, by simply examining its components and their relations.

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• VS 2012 / 2013 AccessViolationException

  - by Goran

  When I run the project (F5) I receive the following exception in IDE: An unhandled exception of type 'System.AccessViolationException' occurred in System.Windows.Forms.dll Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt. Stack trace reports at System.Windows.Forms.UnsafeNativeMethods.SendMessage(HandleRef hWnd, Int32 msg, IntPtr wParam, IntPtr lParam) at System.Windows.Forms.Control.SendMessage(Int32 msg, Int32 wparam, IntPtr lparam) at System.Windows.Forms.Form.UpdateWindowIcon(Boolean redrawFrame) at System.Windows.Forms.Form.CreateHandle() at System.Windows.Forms.Control.get_Handle() at Microsoft.VisualStudio.HostingProcess.HostProc.RunParkingWindowThread() at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() I have never noticed receiving the same exception when running without debugger (CTRL+F5). This is a WPF project, but exception occurs before the App_ctor is executed, so this is external code, and my application code did not start to execute. This happens sporadically, sometimes it happens only once, and sometimes I run the project and get this message for several times in a roll. Then it does not pop up for 5-6 runs, and then starts again. Anyone knows why is this happening? I have just installed clean W8.1 64 bit, VS2013 and TFS 2013 (although I had the same problem with W8 and VS2012, but not as often).

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• How to Loop through LINQ results (VB.NET)

  - by rockinthesixstring

  I've got some code to try and loop through LINQ results, but it doesn't seem to be working. HERE'S THE CODE Public Sub ProcessRequest(ByVal context As System.Web.HttpContext) Implements System.Web.IHttpHandler.ProcessRequest ' the page contenttype is plain text' HttpContext.Current.Response.ContentType = "text/plain" ' store the querystring as a variable' Dim qs As Nullable(Of Integer) = Integer.TryParse(HttpContext.Current.Request.QueryString("ID"), Nothing) ' use the RegionsDataContext' Using RegionDC As New DAL.RegionsDataContext 'create a (q)uery variable' Dim q As Object ' if the querystring PID is not blank' ' then we want to return results based on the PID' If Not qs Is Nothing Then ' that fit within the Parent ID' q = (From r In RegionDC.bt_Regions _ Where r.PID = qs _ Select r.Region).ToArray ' now we loop through the array' ' and write out the ressults' For Each item As DAL.bt_Region In q HttpContext.Current.Response.Write(item.Region & vbCrLf) Next End If End Using End Sub HERE'S THE ERROR Public member 'Region' on type 'String' not found. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.MissingMemberException: Public member 'Region' on type 'String' not found. Source Error: Line 33: ' and write out the ressults Line 34: For Each item In q Line 35: HttpContext.Current.Response.Write(item.Region & vbCrLf) Line 36: Next Line 37: Source File: E:\Projects\businesstrader\App_Code\Handlers\RegionsAutoComplete.vb Line: 35 Stack Trace: [MissingMemberException: Public member 'Region' on type 'String' not found.] Microsoft.VisualBasic.CompilerServices.Container.GetMembers(String& MemberName, Boolean ReportErrors) +509081 Microsoft.VisualBasic.CompilerServices.NewLateBinding.LateGet(Object Instance, Type Type, String MemberName, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, Boolean[] CopyBack) +222 BT.Handlers.RegionsAutoComplete.ProcessRequest(HttpContext context) in E:\Projects\businesstrader\App_Code\Handlers\RegionsAutoComplete.vb:35 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +181 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75 Can anyone tell me what I'm doing wrong?

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• Ado.net dataservices BeginExecuteBatch call works on development fails on production server with Obj

  - by Mike Morley

  We have an ado.net dataservices 1.0 call that is being passed to a [WebGet] service operation as a batch through BeginExecuteBatch. Everything works perfectly on our development server - we have the project configured to use IIS instead of the cassini web server to make it as close to our production server as we can. When we publish to the production server, all the service operations work perfectly except the batch call, which fails with Object does not match target type. . I have not been able to find any cause for this. I can even run a single non-batch style GET operation against the [WebGet] service by copying the URL used in the batch and pasting it in a browser. I have not been able to find any information to help me solve this - any guidance would be most appreciated. Thanks, Mike M. Error message From Fiddler: HTTP/1.1 500 Internal Server Error Content-Type: application/xml DataServiceVersion: 1.0; An error occurred while processing this request. Object does not match target type. System.Reflection.TargetException at System.Reflection.RuntimeMethodInfo.CheckConsistency(Object target) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at System.Data.Services.RequestUriProcessor.CreateFirstSegment(IDataService service, String identifier, Boolean checkRights, String queryPortion, Boolean& crossReferencingUrl) at System.Data.Services.RequestUriProcessor.CreateSegments(String[] segments, IDataService service) at System.Data.Services.RequestUriProcessor.ProcessRequestUri(Uri absoluteRequestUri, IDataService service) at System.Data.Services.DataService`1.BatchDataService.HandleBatchContent(Stream responseStream)

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• "The specified view is invalid" in call to LimitedWebPartManager.AddWebPart in SharePoint 2010

  - by Lee Richardson

  This code used to work in WSS 3.0 / MOSS 2007 in FeatureReceiver.FeatureActivated: using (SPLimitedWebPartManager limitedWebPartManager = Site.GetLimitedWebPartManager("default.aspx", PersonalizationScope.Shared)) { ListViewWebPart listViewWebPart = new ListViewWebPart { Title = title, ListName = list.ID.ToString("B").ToUpper(), ViewGuid = view.ID.ToString("B").ToUpper() }; limitedWebPartManager.AddWebPart(listViewWebPart, zone, position); } I'm trying to convert to SharePoint 2010 and it now fails with: System.ArgumentException: The specified view is invalid. at Microsoft.SharePoint.SPViewCollection.get_Item(Guid guid) at Microsoft.SharePoint.WebPartPages.ListViewWebPart.EnsureListAndView(Boolean requireFullBlownViewSchema) at Microsoft.SharePoint.WebPartPages.ListViewWebPart.get_AppropriateBaseViewId() at Microsoft.SharePoint.WebPartPages.SPWebPartManager.AddWebPartInternal(SPSupersetWebPart superset, Boolean throwIfLocked) at Microsoft.SharePoint.WebPartPages.SPLimitedWebPartManager.AddWebPartInternal(WebPart webPart, String zoneId, Int32 zoneIndex, Boolean throwIfLocked) at Microsoft.SharePoint.WebPartPages.SPLimitedWebPartManager.AddWebPart(WebPart webPart, String zoneId, Int32 zoneIndex) Interestingly enough when I run it from a unit test it works, it only fails in FeatureActivated. When I debug with Reflector it is failing on this line: this.view = this.list.LightweightViews[new Guid(this.ViewGuid)]; list.LightweightViews only returns one view, the default view, even though list.Views returns all of them. I have no idea what LightweightViews is supposed to mean and I'm running out of ideas. Anyone else got any?

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