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• Redirecting http request to two different weblogic servers using the Weblogic proxy and Apache2

  - by Jhon

  Hello All, I've read previous posts like "Redirecting https requests to two different weblogic servers using the Weblogic proxy and Apache2". But I have a different situation and I don't think I'm understanding this to well. I have an Apache 2 server (server1) that will receive http request for my application. Then I have two more servers (server2 and server3) with Web Logic 9.2 runing on ports 7000 (server1) and 8000 (server2). I want the users to enter appname.domain.com and be redirected between the two web logic servers, always keeping appname.domain.com (this is hidding servername:port from URL). How can I manage to do that? Thanks in advanced! Jhon.

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• C# Delegate Invoke Required Issue

  - by Goober

  Scenario I have a C# windows forms application that has a number of processes. These processes run on separate threads and all communicate back to the Main Form class with updates to a log window and a progress bar. I'm using the following code below, which up until now has worked fine, however, I have a few questions. Code delegate void SetTextCallback(string mxID, string text); public void UpdateLog(string mxID, string text) { if (txtOutput.InvokeRequired) { SetTextCallback d = new SetTextCallback(UpdateLog); this.BeginInvoke(d, new object[] { mxID, text }); } else { UpdateProgressBar(text); } } Question Will, calling the above code about 10 times a second, repeatedly, give me errors, exceptions or generally issues?.....Or more to the point, should it give me any of these problems? Occasionally I get OutofMemory Exceptions and the program always seems to crash around this bit of code......

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• How does COM registration work in Windows

  - by Air Benji

  I'm an application packager trying to make sense of how the COM registry keys (SelfReg) interrelate to the given .dll in Windows. ProgID's, AppID's, TypeLibs, Extensions & Verbs are all tied around the CLSID right? Do CLSID's always use Prog/App IDs or could you just have a file extension class? Which bits are optional? Some of it seems to be 'like a router' where there's the two interfaces (internal - .dll) and external (the extension etc). How does this all fit? (The SDK documentation doesn't make sense to me) I ask as this is all pivotal to application 'healing' with Windows Installer (which packagers are all 'big' on, but there's no nitty-gritty breakdowns since its a coder-thing really) ---Edit: Am I safe in assuming that for what COM is registered, it must all link back to the CLSID and cannot be a 'dead-end'? Verbs need extensions which need progid's... What about the AppId's, TypeLibs and Interfaces? How do they interrelate?

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• double.NaN Equality in MS Test

  - by RichK

  Why am I getting this result? [TestMethod] public void nan_test() { Assert.AreEqual(1, double.NaN, 1E-1); <-- Passes Assert.AreEqual(1, double.NaN); <-- Fails } What difference does the delta have in asserting NaN equals a number? Surely it should always return false. I am aware of IsNaN, but that's not useful here (see below). Background: I have a function returning NaN (erroneously) , it was meant to be a real number but the test still passed. I'm using the delta because it's double precision equality, the original test used 1E-9.

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• CALayer flickers when drawing a path

  - by Alexey

  I am using a CALayer to display a path via drawLayer:inContext delegate method, which resides in the view controller of the view that the layer belongs to. Each time the user moves their finger on the screen the path is updated and the layer is redrawn. However, the drawing doesn't keep up with the touches: there is always a slight lag in displaying the last two points of the path. It also flickers, but only while displaying the last two-three points again. If I just do the drawing in the view's drawRect, it works fine and the drawing is definitely fast enough. Does anyone know why it behaves like this? I suspect it is something to do with the layer buffering, but I couldn't find any documentation about it.

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• Build Procedure

  - by sarah xia

  Hi all, My company is putting auto build and deploy procedure in place. What we are doing now is checking out source code from svn and specify the source folder in Ant script. Is it the right way? Can we omit the exporting process and build directly from SVN? Another question is to do with versioning. At the moment, we are creating a tag whenever there is a release and then use the tag number to name the build product, which will be shipped to a client's site. I've done search on the Internet and here and it seems the correct way to name a product is like this: x.y.z.revision. However, our company is quite small and the client always want quick changes and releases. I would like to know what the drawbacks of only using tag number to name the product? And what would be the best approach for small companies like us? Thankyou, Sarah

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• .NET invoking against an arbitrary control.

  - by kerkeslager

  I have a method which takes in a .NET control and calls invoke against it like so: Form.Invoke(Target); However, I've run into an issue numerous times calling this method where due to timing or whatever, the form handle on the form doesn't exist, causing a Invoke or BeginInvoke cannot be called on a control until the window handle has been created error. In frustration, I jokingly changed the code to: MainForm.Invoke(Target); where MainForm is the main window of the application (the form handle for the main form is created at startup and remains active for the entire life cycle of the application). I ran all the tests and manually tested the application and everything seems to work fine despite the fact that this is used everywhere. So my question is, what exactly is the meaning of invoking against a specific control? Is there any downside to just always invoking against a control you know will be active? If not, why does .NET have you invoke against a control in the first place (instead of just creating a static GuiThread.InvokeOnGuiThread(Blah);)?

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• Regex pattern problem in python

  - by mridang

  I need to extract parts of a string using regex in Python. I'm good with basic regex but I'm terrible at lookarounds. I've shown two sample records below. The last big is always a currency field e.g. in the first one it is 4,76. In the second one it is 2,00. The second has an account number that is the pattern of \d{6}-\d{6}. Anything after that is the currency. 24.02 24.02VALINTATALO MEGAHERTSI4,76- 24.02 24.02DOE MRIDANG 157235-1234582,00- Could you help me out with this regex? What I've written so far is given below but it considers everything after the 'dash' in the account number to be the currency. .*?(\d\d\.\d\d)(.*?)\s*(?<!\d{6}-\d{6})(\d*,\d\d) Thanks in advance

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• Scheme early "short circuit return"?

  - by Suan

  I'm trying to find out how I can do an "early return" in a scheme procedure without using a top-level if or cond like construct. (define (win b) (let* ((test (first (first b))) (result (every (lambda (i) (= (list-ref (list-ref b i) i) test)) (enumerate (length b))))) (when (and (not (= test 0)) result) test)) 0) For example, in the code above, I want win to return test if the when condition is met, otherwise return 0. However, what happens is that the procedure will always return 0, regardless of the result of the when condition. The reason I am structuring my code this way is because in this procedure I need to do numerous complex checks (multiple blocks similar to the let* in the example) and putting everything in a big cond would be very unwieldy.

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• How to place a Linearlayout at bottom inside a Relativelayout in android

  - by SANDHYA

  I need to place a linear layout at bottom inside a relativelayout which is the top most parent in xml. How can i do this? Please help me. <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@drawable/background" android:orientation="vertical" > <RelativeLayout ....... <<--- this should occupy total available space </Relativelayout <Linearlayout ....... <<-- this should place at bottom always with height 50dp </LineaLayout> </ReltiveLayout>

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• Leaving out type="text/javascript" language="javascript"

  - by coffeeaddict

  Most of the script tags I create, I always include type="text/javascript" language="javascript" in the tag. My boss however does not. Sometimes he excludes both, sometimes just has language=javascript even without the quotes Now we have not had an issue in any of the major browsers with his tags. I'm talking about all versions of IE, FF, Safari, and Chrome. Personally I feel it's laziness and just totally improper and bad coding practice to leave stuff out like this even if it works without it. Anyone know if both should be included or just one or is it ok to leave both out in ASP.NET?

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• Include params/request information in Rails logger?

  - by Dan Hill

  Hi everyone, I'm trying to get some more information into my Rails logs, specifically the requested URI or current params, if available (and I appreciate that they won't always be). However I just don't seem able to. Here's what I've done so far: #config/environments/production.rb config.logger = Logger.new(config.log_path) config.log_level = :error config.logger.level = Logger::ERROR #config/environment.rb class Logger def format_message(level, time, progname, msg) "**********************************************************************\n#{level} #{time.to_s(:db)} -- #{msg}\n" end end So I can customize the message fine, yet I don't seem to be able to access the params/request variables here. Does anyone know if this is possible, and if so how? Or if there's a better way to get this information? (Perhaps even something Redis based?) Thanks loads, Dan

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• ipad video format [closed]

  - by Mike

  When you use iTunes to sync your videos with the iPhone the videos are always saved with no more than 640 pixels wide, if I am not wrong. What about the iPad? What is the size of videos iTunes syncs with iPad? 1024x768? and what if the video has a dimension below 1024x768? Will it scale up? or will it keep the video at low res and scale when you play? thanks.

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• What is your contribution to open source projects?

  - by Yuval A

  I was always wondering about this seemingly utopic world of open source. Assuming the vast majority of users here are professional software engineers which need some sort of income source, I assume most of us hold stable, money-making jobs. So who are the key players in the open source community? Who are the people which devote their precious time to these projects? What is their benefit? Are the majority just people who see a bug, fix it, submit, and forget about the project? Or are they people constantly involved in the process of building the product? How do you find yourself contributing to open source projects?

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• XNA 3D model collision is inaccurate

  - by Daniel Lopez

  I am creating a classic game in 3d that deals with asteriods and you have to shoot them and avoid being hit from them. I can generate the asteroids just fine and the ship can shoot bullets just fine. But the asteroids always hit the ship even it doesn't look they are even close. I know 2D collision very well but not 3D so can someone please shed some light to my problem. Thanks in advance. Code For ModelRenderer: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { class ModelRenderer { private float aspectratio; private Model model; private Vector3 camerapos; private Vector3 modelpos; private Matrix rotationy; float radiansy = 0; private bool isalive; public ModelRenderer(Model m, float AspectRatio, Vector3 initial_pos, Vector3 initialcamerapos) { isalive = true; model = m; if (model.Meshes.Count == 0) { throw new Exception("Invalid model because it contains zero meshes!"); } modelpos = initial_pos; camerapos = initialcamerapos; aspectratio = AspectRatio; return; } public float RadiusOfSphere { get { return model.Meshes[0].BoundingSphere.Radius; } } public BoundingBox BoxBounds { get { return BoundingBox.CreateFromSphere(model.Meshes[0].BoundingSphere); } } public BoundingSphere SphereBounds { get { return model.Meshes[0].BoundingSphere; } } public Vector3 CameraPosition { set { camerapos = value; } get { return camerapos; } } public bool IsAlive { get { return isalive; } } public Vector3 ModelPosition { set { modelpos = value; } get { return modelpos; } } public void RotateY(float radians) { radiansy += radians; rotationy = Matrix.CreateRotationY(radiansy); } public Matrix RotationY { set { rotationy = value; } get { return rotationy; } } public float AspectRatio { set { aspectratio = value; } get { return aspectratio; } } public void Kill() { isalive = false; } public void Draw(float scale) { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } public void Draw() { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } } Code For Game1: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; int score = 0, lives = 5; SpriteBatch spriteBatch; GameState gstate = GameState.OnMenuScreen; Menu menu = new Menu(Color.Yellow, Color.White); SpriteFont font; Texture2D background; ModelRenderer ship; Model b, a; List<ModelRenderer> bullets = new List<ModelRenderer>(); List<ModelRenderer> asteriods = new List<ModelRenderer>(); float time = 0.0f; int framecount = 0; SoundEffect effect; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = 1280; graphics.PreferredBackBufferHeight = 796; graphics.ApplyChanges(); Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); font = Content.Load<SpriteFont>("Fonts\\Lucida Console"); background = Content.Load<Texture2D>("Textures\\B1_stars"); Model p1 = Content.Load<Model>("Models\\p1_wedge"); b = Content.Load<Model>("Models\\pea_proj"); a = Content.Load<Model>("Models\\asteroid1"); effect = Content.Load<SoundEffect>("Audio\\tx0_fire1"); ship = new ModelRenderer(p1, GraphicsDevice.Viewport.AspectRatio, new Vector3(0, 0, 0), new Vector3(0, 0, 9000)); } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { KeyboardState state = Keyboard.GetState(PlayerIndex.One); switch (gstate) { case GameState.OnMenuScreen: { if (state.IsKeyDown(Keys.Enter)) { switch (menu.SelectedChoice) { case MenuChoices.Play: { gstate = GameState.GameStarted; break; } case MenuChoices.Exit: { this.Exit(); break; } } } if (state.IsKeyDown(Keys.Down)) { menu.MoveSelectedMenuChoiceDown(gameTime); } else if(state.IsKeyDown(Keys.Up)) { menu.MoveSelectedMenuChoiceUp(gameTime); } else { menu.KeysReleased(); } break; } case GameState.GameStarted: { foreach (ModelRenderer bullet in bullets) { if (bullet.ModelPosition.X < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.Z < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.X > (ship.ModelPosition.Z - 4000) && bullet.ModelPosition.Z > (ship.ModelPosition.Z - 4000)) { bullet.ModelPosition += (bullet.RotationY.Forward * 120); } else if (collidedwithasteriod(bullet)) { bullet.Kill(); } else { bullet.Kill(); } } foreach (ModelRenderer asteroid in asteriods) { if (ship.SphereBounds.Intersects(asteroid.BoxBounds)) { lives -= 1; asteroid.Kill(); // This always hits no matter where the ship goes. } else { asteroid.ModelPosition -= (asteroid.RotationY.Forward * 50); } } for (int index = 0; index < asteriods.Count; index++) { if (asteriods[index].IsAlive == false) { asteriods.RemoveAt(index); } } for (int index = 0; index < bullets.Count; index++) { if (bullets[index].IsAlive == false) { bullets.RemoveAt(index); } } if (state.IsKeyDown(Keys.Left)) { ship.RotateY(0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Right)) { ship.RotateY(-0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Up)) { ship.ModelPosition += (ship.RotationY.Forward * 50); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Space)) { time += gameTime.ElapsedGameTime.Milliseconds; if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0.0f; } if ((framecount % 60) == 0) { createasteroid(); framecount = 0; } framecount++; break; } } base.Update(gameTime); } void firebullet() { if (bullets.Count < 3) { ModelRenderer bullet = new ModelRenderer(b, GraphicsDevice.Viewport.AspectRatio, ship.ModelPosition, new Vector3(0, 0, 9000)); bullet.RotationY = ship.RotationY; bullets.Add(bullet); } } void createasteroid() { if (asteriods.Count < 2) { Random random = new Random(); float z = random.Next(-13000, -11000); float x = random.Next(-9000, -8000); Random random2 = new Random(); int degrees = random.Next(0, 45); float radians = MathHelper.ToRadians(degrees); ModelRenderer asteroid = new ModelRenderer(a, GraphicsDevice.Viewport.AspectRatio, new Vector3(x, 0, z), new Vector3(0,0, 9000)); asteroid.RotateY(radians); asteriods.Add(asteroid); } } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); switch (gstate) { case GameState.OnMenuScreen: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); menu.DrawMenu(ref spriteBatch, font, new Vector2(GraphicsDevice.Viewport.Width / 2, GraphicsDevice.Viewport.Height / 2) - new Vector2(50f), 100f); spriteBatch.End(); break; } case GameState.GameStarted: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); spriteBatch.DrawString(font, "Score: " + score.ToString() + "\nLives: " + lives.ToString(), Vector2.Zero, Color.White); spriteBatch.End(); ship.Draw(); foreach (ModelRenderer bullet in bullets) { bullet.Draw(); } foreach (ModelRenderer asteroid in asteriods) { asteroid.Draw(0.1f); } break; } } base.Draw(gameTime); } bool collidedwithasteriod(ModelRenderer bullet) { foreach (ModelRenderer asteroid in asteriods) { if (bullet.SphereBounds.Intersects(asteroid.BoxBounds)) { score += 10; asteroid.Kill(); return true; } } return false; } } } }

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• How can I write javascript that will load and print a web page to an image file and put that file in a specified location

  - by Rben

  Here's what I want to do: Load a web page from a specific location Print that web page into a jpeg, png, or other graphic file format Upload that image to another site, or save it to a location on my local network I know about window.print(), but that always seems to open up a print window, and I'd like to do as much of this operation silently as possible. Essentially, I want to be able to take a snap shot of the web page so it can be put in a directory that is accessed by one of those electronic picture frames. They can either access a web-based service, or a directory on the local network. Thanks in advance for your help, Rben

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• Ideas for web development practical jokes?

  - by Ellie P.

  I am a web developer for a Django-based site for a student organization, and I have the opportunity to make the website temporarily absurd for a day of general campus-wide debauchery and chaos (long story, doesn't matter.) What are your best ideas for web development practical jokes (that you could never use in the real world)? For example, one idea we had was to use a client-side script to convert each character to its upside down equivalent in Unicode, si?? ??i? ?ui????os. I'm not necessarily looking for Django-specific solutions. I imagine most of these things would happen on the front-end. I am also quite aware that usability will suffer considerably--the point is to be fun for a day, and there will always be a link to the normal version of the site. Also, everything must be relatively cosmetic and easily reversible--I'm happy to swap out static CSS/JS/HTML/templates/images, and even temporarily add a django view, but no messing with the data level!

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• How do I insert into a unique key into a table?

  - by Ben McCormack

  I want to insert data into a table where I don't know the next unique key that I need. I'm not sure how to format my INSERT query so that the value of the Key field is 1 greater than the maximum value for the key in the table. I know this is a hack, but I'm just running a quick test against a database and need to make sure I always send over a Unique key. Here's the SQL I have so far: INSERT INTO [CMS2000].[dbo].[aDataTypesTest] ([KeyFld] ,[Int1]) VALUES ((SELECT Max([KeyFld]) FROM [dbo].[aDataTypesTest]) + 1 ,1) which errors out with: Msg 1046, Level 15, State 1, Line 5 Subqueries are not allowed in this context. Only scalar expressions are allowed. I'm not able to modify the underlying database table. What do I need to do to ensure a unique insert in my INSERT SQL code?

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• XCode Intellisense Question

  - by Cody C

  I've always seem to work around this lack of knowledge but I thought I would ask the community. I hope this question will make sense. In XCode, when I call a function that has several parameter the intellisense pops up. When I hit TAB the first time, it takes me directly to the first parameter. How do I get to the next parameter easily. If I hit TAB again, it puts an actual TAB in the line. For the last month I've been using arrow keys but I figured there must be a keyboard shortcut.

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• DataReader - hardcode ordinals?

  - by David Neale

  When returning data from a DataReader I would typically use the ordinal reference on the DataReader to grab the relevant column: if (dr.HasRows) Console.WriteLine(dr[0].ToString()); (OR dr.GetString(0); OR (string)dr[0];)... I have always done this because I was advised at an early stage that using dr["ColumnName"] or a more elegant way of indexing causes a performance hit. However, whilst everything is becoming increasingly strongly-typed I feel more uncomfortable with this. I'm also aware that the above does not check for DBNull. How should data be returned from a DataReader?

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• Is there a way to export an XSD schema from a DataContract

  - by Eric

  I'm using DataContractSerializer to serialize/deserialize my classes to/from XML. Everything works fine, but at some point I'd like to establish a standard schema for the format of these XML files independent of the actual code. That way if something breaks in the serialization process I can always go back and check what the standard schema should be. Or if I do need to modify the schema the modification is an explicit decision rather then just a later affect of modifying my code. In addition, other people may be writing other software that may not be .NET based that would need to read from these XML files. I'd like to be able to provide them with some kind of documentation of the schema. Is there some relationship between a DataContract and an XSD schema. Is there a way to export the DataContract attributes in classes as an XSD schema?

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• R Package Installation with Oracle R Enterprise

  - by Sherry LaMonica-Oracle

  Normal 0 false false false EN-US X-NONE X-NONE Programming languages give developers the opportunity to write reusable functions and to bundle those functions into logical deployable entities. In R, these are called packages. R has thousands of such packages provided by an almost equally large group of third-party contributors. To allow others to benefit from these packages, users can share packages on the CRAN system for use by the vast R development community worldwide. R's package system along with the CRAN framework provides a process for authoring, documenting and distributing packages to millions of users. In this post, we'll illustrate the various ways in which such R packages can be installed for use with R and together with Oracle R Enterprise. In the following, the same instructions apply when using either open source R or Oracle R Distribution. In this post, we cover the following package installation scenarios for: R command line Linux shell command line Use with Oracle R Enterprise Installation on Exadata or RAC Installing all packages in a CRAN Task View Troubleshooting common errors 1. R Package Installation BasicsR package installation basics are outlined in Chapter 6 of the R Installation and Administration Guide. There are two ways to install packages from the command line: from the R command line and from the shell command line. For this first example on Oracle Linux using Oracle R Distribution, we’ll install the arules package as root so that packages will be installed in the default R system-wide location where all users can access it, /usr/lib64/R/library.Within R, using the install.packages function always attempts to install the latest version of the requested package available on CRAN:R> install.packages("arules")If the arules package depends upon other packages that are not already installed locally, the R installer automatically downloads and installs those required packages. This is a huge benefit that frees users from the task of identifying and resolving those dependencies.You can also install R from the shell command line. This is useful for some packages when an internet connection is not available or for installing packages not uploaded to CRAN. To install packages this way, first locate the package on CRAN and then download the package source to your local machine. For example:$ wget http://cran.r-project.org/src/contrib/arules_1.1-2.tar.gz Then, install the package using the command R CMD INSTALL:$ R CMD INSTALL arules_1.1-2.tar.gzA major difference between installing R packages using the R package installer at the R command line and shell command line is that package dependencies must be resolved manually at the shell command line. Package dependencies are listed in the Depends section of the package’s CRAN site. If dependencies are not identified and installed prior to the package’s installation, you will see an error similar to:ERROR: dependency ‘xxx’ is not available for package ‘yyy’As a best practice and to save time, always refer to the package’s CRAN site to understand the package dependencies prior to attempting an installation. If you don’t run R as root, you won’t have permission to write packages into the default system-wide location and you will be prompted to create a personal library accessible by your userid. You can accept the personal library path chosen by R, or specify the library location by passing parameters to the install.packages function. For example, to create an R package repository in your home directory: R> install.packages("arules", lib="/home/username/Rpackages")or$ R CMD INSTALL arules_1.1-2.tar.gz --library=/home/username/RpackagesRefer to the install.packages help file in R or execute R CMD INSTALL --help at the shell command line for a full list of command line options.To set the library location and avoid having to specify this at every package install, simply create the R startup environment file .Renviron in your home area if it does not already exist, and add the following piece of code to it:R_LIBS_USER = "/home/username/Rpackages" 2. Setting the RepositoryEach time you install an R package from the R command line, you are asked which CRAN mirror, or server, R should use. To set the repository and avoid having to specify this during every package installation, create the R startup command file .Rprofile in your home directory and add the following R code to it:cat("Setting Seattle repository")r = getOption("repos") r["CRAN"] = "http://cran.fhcrc.org/"options(repos = r)rm(r) This code snippet sets the R package repository to the Seattle CRAN mirror at the start of each R session. 3. Installing R Packages for use with Oracle R EnterpriseEmbedded R execution with Oracle R Enterprise allows the use of CRAN or other third-party R packages in user-defined R functions executed on the Oracle Database server. The steps for installing and configuring packages for use with Oracle R Enterprise are the same as for open source R. The database-side R engine just needs to know where to find the R packages.The Oracle R Enterprise installation is performed by user oracle, which typically does not have write permission to the default site-wide library, /usr/lib64/R/library. On Linux and UNIX platforms, the Oracle R Enterprise Server installation provides the ORE script, which is executed from the operating system shell to install R packages and to start R. The ORE script is a wrapper for the default R script, a shell wrapper for the R executable. It can be used to start R, run batch scripts, and build or install R packages. Unlike the default R script, the ORE script installs packages to a location writable by user oracle and accessible by all ORE users - $ORACLE_HOME/R/library.To install a package on the database server so that it can be used by any R user and for use in embedded R execution, an Oracle DBA would typically download the package source from CRAN using wget. If the package depends on any packages that are not in the R distribution in use, download the sources for those packages, also.  For a single Oracle Database instance, replace the R script with ORE to install the packages in the same location as the Oracle R Enterprise packages. $ wget http://cran.r-project.org/src/contrib/arules_1.1-2.tar.gz$ ORE CMD INSTALL arules_1.1-2.tar.gzBehind the scenes, the ORE script performs the equivalent of setting R_LIBS_USER to the value of $ORACLE_HOME/R/library, and all R packages installed with the ORE script are installed to this location. For installing a package on multiple database servers, such as those in an Oracle Real Application Clusters (Oracle RAC) or a multinode Oracle Exadata Database Machine environment, use the ORE script in conjunction with the Exadata Distributed Command Line Interface (DCLI) utility.$ dcli -g nodes -l oracle ORE CMD INSTALL arules_1.1-1.tar.gz The DCLI -g flag designates a file containing a list of nodes to install on, and the -l flag specifies the user id to use when executing the commands. For more information on using DCLI with Oracle R Enterprise, see Chapter 5 in the Oracle R Enterprise Installation Guide.If you are using an Oracle R Enterprise client, install the package the same as any R package, bearing in mind that you must install the same version of the package on both the client and server machines to avoid incompatibilities. 4. CRAN Task ViewsCRAN also maintains a set of Task Views that identify packages associated with a particular task or methodology. Task Views are helpful in guiding users through the huge set of available R packages. They are actively maintained by volunteers who include detailed annotations for routines and packages. If you find one of the task views is a perfect match, you can install every package in that view using the ctv package - an R package for automating package installation. To use the ctv package to install a task view, first, install and load the ctv package.R> install.packages("ctv")R> library(ctv)Then query the names of the available task views and install the view you choose.R> available.views() R> install.views("TimeSeries") 5. Using and Managing R packages To use a package, start up R and load packages one at a time with the library command.Load the arules package in your R session. R> library(arules)Verify the version of arules installed.R> packageVersion("arules")[1] '1.1.2'Verify the version of arules installed on the database server using embedded R execution.R> ore.doEval(function() packageVersion("arules"))View the help file for the apropos function in the arules packageR> ?aproposOver time, your package repository will contain more and more packages, especially if you are using the system-wide repository where others are adding additional packages. It’s good to know the entire set of R packages accessible in your environment. To list all available packages in your local R session, use the installed.packages command:R> myLocalPackages <- row.names(installed.packages())R> myLocalPackagesTo access the list of available packages on the ORE database server from the ORE client, use the following embedded R syntax: R> myServerPackages <- ore.doEval(function() row.names(installed.packages()) R> myServerPackages 6. Troubleshooting Common ProblemsInstalling Older Versions of R packagesIf you immediately upgrade to the latest version of R, you will have no problem installing the most recent versions of R packages. However, if your version of R is older, some of the more recent package releases will not work and install.packages will generate a message such as: Warning message: In install.packages("arules") : package ‘arules’ is not availableThis is when you have to go to the Old sources link on the CRAN page for the arules package and determine which version is compatible with your version of R.Begin by determining what version of R you are using:$ R --versionOracle Distribution of R version 3.0.1 (--) -- "Good Sport" Copyright (C) The R Foundation for Statistical Computing Platform: x86_64-unknown-linux-gnu (64-bit)Given that R-3.0.1 was released May 16, 2013, any version of the arules package released after this date may work. Scanning the arules archive, we might try installing version 0.1.1-1, released in January of 2014:$ wget http://cran.r-project.org/src/contrib/Archive/arules/arules_1.1-1.tar.gz$ R CMD INSTALL arules_1.1-1.tar.gzFor use with ORE:$ ORE CMD INSTALL arules_1.1-1.tar.gzThe "package not available" error can also be thrown if the package you’re trying to install lives elsewhere, either another R package site, or it’s been removed from CRAN. A quick Google search usually leads to more information on the package’s location and status.Oracle R Enterprise is not in the R library pathOn Linux hosts, after installing the ORE server components, starting R, and attempting to load the ORE packages, you may receive the error:R> library(ORE)Error in library(ORE) : there is no package called ‘ORE’If you know the ORE packages have been installed and you receive this error, this is the result of not starting R with the ORE script. To resolve this problem, exit R and restart using the ORE script. After restarting R and ">running the command to load the ORE packages, you should not receive any errors.$ ORER> library(ORE)On Windows servers, the solution is to make the location of the ORE packages visible to R by adding them to the R library paths. To accomplish this, exit R, then add the following lines to the .Rprofile file. On Windows, the .Rprofile file is located in R\etc directory C:\Program Files\R\R-<version>\etc. Add the following lines:.libPaths("<path to $ORACLE_HOME>/R/library")The above line will tell R to include the R directory in the Oracle home as part of its search path. When you start R, the path above will be included, and future R package installations will also be saved to $ORACLE_HOME/R/library. This path should be writable by the user oracle, or the userid for the DBA tasked with installing R packages.Binary package compiled with different version of RBy default, R will install pre-compiled versions of packages if they are found. If the version of R under which the package was compiled does not match your installed version of R you will get an error message:Warning message: package ‘xxx’ was built under R version 3.0.0The solution is to download the package source and build it for your version of R.$ wget http://cran.r-project.org/src/contrib/Archive/arules/arules_1.1-1.tar.gz$ R CMD INSTALL arules_1.1-1.tar.gzFor use with ORE:$ ORE CMD INSTALL arules_1.1-1.tar.gzUnable to execute files in /tmp directoryBy default, R uses the /tmp directory to install packages. On security conscious machines, the /tmp directory is often marked as "noexec" in the /etc/fstab file. This means that no file under /tmp can ever be executed, and users who attempt to install R package will receive an error:ERROR: 'configure' exists but is not executable -- see the 'R Installation and Administration Manual’The solution is to set the TMP and TMPDIR environment variables to a location which R will use as the compilation directory. For example:$ mkdir <some path>/tmp$ export TMPDIR= <some path>/tmp$ export TMP= <some path>/tmpThis error typically appears on Linux client machines and not database servers, as Oracle Database writes to the value of the TMP environment variable for several tasks, including holding temporary files during database installation. 7. Creating your own R packageCreating your own package and submitting to CRAN is for advanced users, but it is not difficult. The procedure to follow, along with details of R's package system, is detailed in the Writing R Extensions manual.

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• Handling Hide/Show dock icon menu in AIR on OS X

  - by Alan

  I'm trying to figure out how to access the Show/Hide option that OS X automatically adds to the dock icon menu. The problem is that no matter what I do to hide my app, the dock icon menu will always show Hide and only if I click that option does it switch to Show. I want to have my app toggle visibility using the Invoke event but if a user hides the app that way and then right clicks the dock icon, they won't see Show, just Hide. Is there an event I can monitor for it? Or that I can trigger? I just want to have that menu option status be synced to whatever visibility status I set programatically. This has been driving me nuts!

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• Can you clear jquery ajax cache?

  - by chobo2

  Hi I am wondering is it possible to clear the cache from a particular ajax method? Say if I have this $.ajax({ url: "test.html", cache: true, success: function(html){ $("#results").append(html); } }); Now 99% of the time a cached result can be used since it should always be same content. However if a user updates this content it of course changes. If it is cached and it would still show the old content. So it would be cool if I could pick out this cache for this method and clear it and all other cached stuff would stay. Can this be done?

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• Setting classpath java for use in Runtime.exec

  - by phil swenson

  I am trying to spawn a process using Runtime.exec. I want to use my current classpath : System.getProperty("java.class.path") Unfortunately, I am having all kinds of issues. When it works on my mac, it doesn't work on Windows. And doesn't work on my mac ever when there is a space in the classpath. The error I always get is ClassDefNotFound, so it's related to how I'm building and passing in the classpath. here is some sample code: String startClass = "com.test.MyClass" String javaHome = System.getProperty("java.home"); String javaCmd = javaHome + "/bin/java"; String classPath = "-Djava.class.path=" + System.getProperty("java.class.path"); String[] commands = new String[]{javaCmd, classPath, startClass}; String commandString = StringUtils.join(commands, " "); Process process = Runtime.getRuntime().exec(commandString); So, how should I setup the classpath? Thanks for any help

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