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• Sprite Animation in Android with OpenGL ES

  - by lijo john

  How to do a sprite animation in android using OpenGL ES? What i have done : Now I am able to draw a rectangle and apply my texture(Spritesheet) to it What I need to know : Now the rectangle shows the whole sprite sheet as a whole How to show a single action from sprite sheet at a time and make the animation It will be very help full if anyone can share any idea's , links to tutorials and suggestions. Advanced Thanks to All

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• Component-based Rendering

  - by Kikaimaru

  I have component Renderer, that Draws Texture2D (or sprite) According to component-based architecture i should have only method OnUpdate, and there should be my rendering code, something like spriteBatch.Draw(Texture, Vector2.Zero, Color.White) But first I need to do spriteBatch.Begin();. Where should i call it? And how can I make sure it's called before any Renderer components OnUpdate method? (i need to do more stuff then just Begin() i also need to set right rendertarget for camera etc.)

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• How can I support the creation and rendering of both interior and exterior environments?

  - by Nick

  Say I already have a renderer that can support outdoor terrain and environment rendering. How would I go about adding support for interior environments (for example, like World of Warcraft's dungeons) to my game? I'm interested both in how I should fit the interiors into my content creation process (for example, I thought about leaving holes in the terrain mesh into which I can "paste" the interior dungeon mesh at runtime) and how to render them (it seems like I'd want a different rendering flow other than a blended texture rendering phase that terrain uses).

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• ADF Business Components

  - by Arda Eralp

  ADF Business Components and JDeveloper simplify the development, delivery, and customization of business applications for the Java EE platform. With ADF Business Components, developers aren't required to write the application infrastructure code required by the typical Java EE application to: Connect to the database Retrieve data Lock database records Manage transactions   ADF Business Components addresses these tasks through its library of reusable software components and through the supporting design time facilities in JDeveloper. Most importantly, developers save time using ADF Business Components since the JDeveloper design time makes typical development tasks entirely declarative. In particular, JDeveloper supports declarative development with ADF Business Components to: Author and test business logic in components which automatically integrate with databases Reuse business logic through multiple SQL-based views of data, supporting different application tasks Access and update the views from browser, desktop, mobile, and web service clients Customize application functionality in layers without requiring modification of the delivered application The goal of ADF Business Components is to make the business services developer more productive.   ADF Business Components provides a foundation of Java classes that allow your business-tier application components to leverage the functionality provided in the following areas: Simplifying Data Access Design a data model for client displays, including only necessary data Include master-detail hierarchies of any complexity as part of the data model Implement end-user Query-by-Example data filtering without code Automatically coordinate data model changes with business services layer Automatically validate and save any changes to the database   Enforcing Business Domain Validation and Business Logic Declaratively enforce required fields, primary key uniqueness, data precision-scale, and foreign key references Easily capture and enforce both simple and complex business rules, programmatically or declaratively, with multilevel validation support Navigate relationships between business domain objects and enforce constraints related to compound components   Supporting Sophisticated UIs with Multipage Units of Work Automatically reflect changes made by business service application logic in the user interface Retrieve reference information from related tables, and automatically maintain the information when the user changes foreign-key values Simplify multistep web-based business transactions with automatic web-tier state management Handle images, video, sound, and documents without having to use code Synchronize pending data changes across multiple views of data Consistently apply prompts, tooltips, format masks, and error messages in any application Define custom metadata for any business components to support metadata-driven user interface or application functionality Add dynamic attributes at runtime to simplify per-row state management   Implementing High-Performance Service-Oriented Architecture Support highly functional web service interfaces for business integration without writing code Enforce best-practice interface-based programming style Simplify application security with automatic JAAS integration and audit maintenance "Write once, run anywhere": use the same business service as plain Java class, EJB session bean, or web service   Streamlining Application Customization Extend component functionality after delivery without modifying source code Globally substitute delivered components with extended ones without modifying the application   ADF Business Components implements the business service through the following set of cooperating components: Entity object An entity object represents a row in a database table and simplifies modifying its data by handling all data manipulation language (DML) operations for you. These are basically your 1 to 1 representation of a database table. Each table in the database will have 1 and only 1 EO. The EO contains the mapping between columns and attributes. EO's also contain the business logic and validation. These are you core data services. They are responsible for updating, inserting and deleting records. The Attributes tab displays the actual mapping between attributes and columns, the mapping has following fields: Name : contains the name of the attribute we expose in our data model. Type : defines the data type of the attribute in our application. Column : specifies the column to which we want to map the attribute with Column Type : contains the type of the column in the database   View object A view object represents a SQL query. You use the full power of the familiar SQL language to join, filter, sort, and aggregate data into exactly the shape required by the end-user task. The attributes in the View Objects are actually coming from the Entity Object. In the end the VO will generate a query but you basically build a VO by selecting which EO need to participate in the VO and which attributes of those EO you want to use. That's why you have the Entity Usage column so you can see the relation between VO and EO. In the query tab you can clearly see the query that will be generated for the VO. At this stage we don't need it and just use it for information purpose. In later stages we might use it. Application module An application module is the controller of your data layer. It is responsible for keeping hold of the transaction. It exposes the data model to the view layer. You expose the VO's through the Application Module. This is the abstraction of your data layer which you want to show to the outside word.It defines an updatable data model and top-level procedures and functions (called service methods) related to a logical unit of work related to an end-user task. While the base components handle all the common cases through built-in behavior, customization is always possible and the default behavior provided by the base components can be easily overridden or augmented. When you create EO's, a foreign key will be translated into an association in our model. It defines the type of relation and who is the master and child as well as how the visibility of the association looks like. A similar concept exists to identify relations between view objects. These are called view links. These are almost identical as association except that a view link is based upon attributes defined in the view object. It can also be based upon an association. Here's a short summary: Entity Objects: representations of tables Association: Relations between EO's. Representations of foreign keys View Objects: Logical model View Links: Relationships between view objects Application Model: interface to your application  

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• Rain drops on screen

  - by user1075940

  I am trying to make simple rain drop effect on screen.Something like this http://fc00.deviantart.net/fs20/f/2007/302/5/6/Rain_drops_by_rockraikar.png My idea is to: Create small drop shaped normal textures,randomly put few on screen,apply texture perturbation and mix with current frame pixels. Here are my questions: -Does this idea even have sense?How professionals do this effect?Everything from text to code will be appreciated -How to pass pixels to shader of already rendered frame?

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• Create a kind of Interface c++ [migrated]

  - by Liuka

  I'm writing a little 2d rendering framework with managers for input and resources like textures and meshes (for 2d geometry models, like quads) and they are all contained in a class "engine" that interacts with them and with a directX class. So each class have some public methods like init or update. They are called by the engine class to render the resources, create them, but a lot of them should not be called by the user: //in pseudo c++ //the textures manager class class TManager { private: vector textures; .... public: init(); update(); renderTexture(); //called by the "engine class" loadtexture(); gettexture(); //called by the user } class Engine { private: Tmanager texManager; public: Init() { //initialize all the managers } Render(){...} Update(){...} Tmanager* GetTManager(){return &texManager;} //to get a pointer to the manager //if i want to create or get textures } In this way the user, calling Engine::GetTmanager will have access to all the public methods of Tmanager, including init update and rendertexture, that must be called only by Engine inside its init, render and update functions. So, is it a good idea to implement a user interface in the following way? //in pseudo c++ //the textures manager class class TManager { private: vector textures; .... public: init(); update(); renderTexture(); //called by the "engine class" friend class Tmanager_UserInterface; operator Tmanager_UserInterface*(){return reinterpret_cast<Tmanager_UserInterface*>(this)} } class Tmanager_UserInterface : private Tmanager { //delete constructor //in this class there will be only methods like: loadtexture(); gettexture(); } class Engine { private: Tmanager texManager; public: Init() Render() Update() Tmanager_UserInterface* GetTManager(){return texManager;} } //in main function //i need to load a texture //i always have access to Engine class engine-GetTmanger()-LoadTexture(...) //i can just access load and get texture; In this way i can implement several interface for each object, keeping visible only the functions i (and the user) will need. There are better ways to do the same?? Or is it just useless(i dont hide the "framework private functions" and the user will learn to dont call them)? Before i have used this method: class manager { public: //engine functions userfunction(); } class engine { private: manager m; public: init(){//call manager init function} manageruserfunciton() { //call manager::userfunction() } } in this way i have no access to the manager class but it's a bad way because if i add a new feature to the manager i need to add a new method in the engine class and it takes a lot of time. sorry for the bad english.

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• Collision Detection for 2D

  - by Bhaskar

  I am working on a simple game, where I need to do a collision detection of two Texture2D. The code I have written is: bool perPixelCollission = false; Texture2D texture1 = sprite1.Texture; Texture2D texture2 = sprite1.Texture; Vector2 position1 = new Vector2(sprite1.CurrentScope.X, sprite1.CurrentScope.Y); Vector2 position2 = new Vector2(sprite2.CurrentScope.X, sprite2.CurrentScope.Y); uint[] bitsA = new uint[texture1.Width * texture1.Height]; uint[] bitsB = new uint[texture2.Width * texture2.Height]; Rectangle texture1Rectangle = new Rectangle(Convert.ToInt32(position1.X), Convert.ToInt32(position1.Y), texture1.Width, texture1.Height); Rectangle texture2Rectangle = new Rectangle(Convert.ToInt32(position2.X), Convert.ToInt32(position2.Y), texture2.Width, texture2.Height); texture1.GetData<uint>(bitsA); texture2.GetData<uint>(bitsB); int x1 = Math.Max(texture1Rectangle.X, texture2Rectangle.X); int x2 = Math.Min(texture1Rectangle.X + texture1Rectangle.Width, texture2Rectangle.X + texture2Rectangle.Width); int y1 = Math.Max(texture1Rectangle.Y, texture2Rectangle.Y); int y2 = Math.Min(texture1Rectangle.Y + texture1Rectangle.Height, texture2Rectangle.Y + texture2Rectangle.Height); for (int y = y1; y < y2; ++y) { for (int x = x1; x < x2; ++x) { if (((bitsA[(x - texture1Rectangle.X) + (y - texture1Rectangle.Y) * texture1Rectangle.Width] & 0xFF000000) >> 24) > 20 && ((bitsB[(x - texture2Rectangle.X) + (y - texture2Rectangle.Y) * texture2Rectangle.Width] & 0xFF000000) >> 24) > 20) { perPixelCollission = true; break; } } // Reduce amount of looping by breaking out of this. if (perPixelCollission) { break; } } return perPixelCollission; But this code is really making the game slow. Where can I get some very good collision detection tutorial and code? What is wrong in this code?

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• How to send multiple MVP matrices to a vertex shader in OpenGL ES 2.0

  - by Carbon Crystal

  I'm working my way through optimizing the rendering of sprites in a 2D game using OpenGL ES and I've hit the limit of my knowledge when it comes to GLSL and vertex shaders. I have two large float buffers containing my vertex coordinates and texture coordinates (eventually this will be one buffer) for multiple sprites in order to perform a single glDrawArrays call. This works but I've hit a snag when it comes to passing the transformation matrix into the vertex shader. My shader code is: uniform mat4 u_MVPMatrix; attribute vec4 a_Position; attribute vec2 a_TexCoordinate; varying vec2 v_TexCoordinate; void main() { v_TexCoordinate = a_TexCoordinate; gl_Position = u_MVPMatrix * a_Position; } In Java (Android) I am using a FloatBuffer to store the vertex/texture data and this is provided to the shader like so: mGlEs20.glVertexAttribPointer(mVertexHandle, Globals.GL_POSITION_VERTEX_COUNT, GLES20.GL_FLOAT, false, 0, mVertexCoordinates); mGlEs20.glVertexAttribPointer(mTextureCoordinateHandle, Globals.GL_TEXTURE_VERTEX_COUNT, GLES20.GL_FLOAT, false, 0, mTextureCoordinates); (The Globals.GL_POSITION_VERTEX_COUNT etc are just integers with the value of 2 right now) And I'm passing the MVP (Model/View/Projection) matrix buffer like this: GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mModelCoordinates); (mModelCoordinates is a FloatBuffer containing 16-float sequences representing the MVP matrix for each sprite) This renders my scene but all the sprites share the same transformation, so it's obviously only picking the first 16 elements from the buffer which makes sense since I am passing in "1" as the second parameter. The documentation for this method says: "This should be 1 if the targeted uniform variable is not an array of matrices, and 1 or more if it is an array of matrices." So I tried modifying the shader with a fixed size array large enough to accomodate most of my scenarios: uniform mat4 u_MVPMatrix[1000]; But this lead to an error in the shader: cannot convert from 'uniform array of 4X4 matrix of float' to 'Position 4-component vector of float' This just seems wrong anyway as it's not clear to me how the shader would know when to transition to the next matrix anyway. Anyone have an idea how I can get my shader to pick up a different MVP matrix (i.e. the NEXT 16 floats) from my MVP buffer for every 4 vertices it encounters? (I am using GL_TRIANGLE_STRIP so each sprite has 4 vertices). Thanks!

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• Changing coordinate system from Z-up to Y-up

  - by Jari Komppa

  Blender's coordinate system is different from what I'm used to, in that Z points upwards instead of Y. What would be the simplest way of converting all the world data (so that all animations, texture coordinates, etc still work) so that Y points upwards? Clarification: Object positions are defined as matrices, so just switching translation/rotation/scale information in matrices is not a trivial task.

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• GLSL per pixel lighting with custom light type

  - by Justin

  Ok, I am having a big problem here. I just got into GLSL yesterday, so the code will be terrible, I'm sure. Basically, I am attempting to make a light that can be passed into the fragment shader (for learning purposes). I have four input values: one for the position of the light, one for the color, one for the distance it can travel, and one for the intensity. I want to find the distance between the light and the fragment, then calculate the color from there. The code I have gives me a simply gorgeous ring of light that get's twisted and widened as the matrix is modified. I love the results, but it is not even close to what I am after. I want the light to be moved with all of the vertices, so it is always in the same place in relation to the objects. I can easily take it from there, but getting that to work seems to be impossible with my current structure. Can somebody give me a few pointers (pun not intended)? Vertex shader: attribute vec4 position; attribute vec4 color; attribute vec2 textureCoordinates; varying vec4 colorVarying; varying vec2 texturePosition; varying vec4 fposition; varying vec4 lightPosition; varying float lightDistance; varying float lightIntensity; varying vec4 lightColor; void main() { vec4 ECposition = gl_ModelViewMatrix * gl_Vertex; vec3 tnorm = normalize(vec3 (gl_NormalMatrix * gl_Normal)); fposition = ftransform(); gl_Position = fposition; gl_TexCoord[0] = gl_MultiTexCoord0; fposition = ECposition; lightPosition = vec4(0.0, 0.0, 5.0, 0.0) * gl_ModelViewMatrix * gl_Vertex; lightDistance = 5.0; lightIntensity = 1.0; lightColor = vec4(0.2, 0.2, 0.2, 1.0); } Fragment shader: varying vec4 colorVarying; varying vec2 texturePosition; varying vec4 fposition; varying vec4 lightPosition; varying float lightDistance; varying float lightIntensity; varying vec4 lightColor; uniform sampler2D texture; void main() { float l_distance = sqrt((gl_FragCoord.x * lightPosition.x) + (gl_FragCoord.y * lightPosition.y) + (gl_FragCoord.z * lightPosition.z)); float l_value = lightIntensity / (l_distance / lightDistance); vec4 l_color = vec4(l_value * lightColor.r, l_value * lightColor.g, l_value * lightColor.b, l_value * lightColor.a); vec4 color; color = texture2D(texture, gl_TexCoord[0].st); gl_FragColor = l_color * color; //gl_FragColor = fposition; }

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• Getting started with object detection - Image segmentation algorithm

  - by Dev Kanchen

  Just getting started on a hobby object-detection project. My aim is to understand the underlying algorithms and to this end the overall accuracy of the results is (currently) more important than actual run-time. I'm starting with trying to find a good image segmentation algorithm that provide a good jump-off point for the object detection phase. The target images would be "real-world" scenes. I found two techniques which mirrored my thoughts on how to go about this: Graph-based Image Segmentation: http://www.cs.cornell.edu/~dph/papers/seg-ijcv.pdf Contour and Texture Analysis for Image Segmentation: http://www.eng.utah.edu/~bresee/compvision/files/MalikBLS.pdf The first one was really intuitive to understand and seems simple enough to implement, while the second was closer to my initial thoughts on how to go about this (combine color/intensity and texture information to find regions). But it's an order of magnitude more complex (at least for me). My question is - are there any other algorithms I should be looking at that provide the kind of results that these two, specific papers have arrived at. Are there updated versions of these techniques already floating around. Like I mentioned earlier, the goal is relative accuracy of image segmentation (with an eventual aim to achieve a degree of accuracy of object detection) over runtime, with the algorithm being able to segment an image into "naturally" or perceptually important components, as these two algorithms do (each to varying extents). Thanks! P.S.1: I found these two papers after a couple of days of refining my search terms and learning new ones relevant to the exact kind of techniques I was looking for. :) I have just about reached the end of my personal Google creativity, which is why I am finally here! Thanks for the help. P.S.2: I couldn't find good tags for this question. If some relevant ones exist, @mods please add them. P.S.3: I do not know if this is a better fit for cstheory.stackexchange (or even cs.stackexchange). I looked but cstheory seems more appropriate for intricate algorithmic discussions than a broad question like this. Also, I couldn't find any relevant tags there either! But please do move if appropriate.

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• Trying to use stencils in 2D while retaining layer depth

  - by Steve

  This is a screen of what's going on just so you can get a frame of reference. http://i935.photobucket.com/albums/ad199/fobwashed/tilefloors.png The problem I'm running into is that my game is slowing down due to the amount of texture swapping I'm doing during my draw call. Since walls, characters, floors, and all objects are on their respective sprite sheet containing those types, per tile draw, the loaded texture is swapping no less than 3 to 5+ times as it cycles and draws the sprites in order to layer properly. Now, I've tried throwing all common objects together into their respective lists, and then using layerDepth drawing them that way which makes things a lot better, but the new problem I'm running into has to do with the way my doors/windows are drawn on walls. Namely, I was using stencils to clear out a block on the walls that are drawn in the shape of the door/window so that when the wall would draw, it would have a door/window sized hole in it. This is the way my draw was set up for walls when I was going tile by tile rather than grouped up common objects. first it would check to see if a door/window was on this wall. If not, it'd skip all the steps and just draw normally. Otherwise end the current spriteBatch Clear the buffers with a transparent color to preserve what was already drawn start a new spritebatch with stencil settings draw the door area end the spriteBatch start a new spritebatch that takes into account the previously set stencil draw the wall which will now be drawn with a hole in it end that spritebatch start a new spritebatch with the normal settings to continue drawing tiles In the tile by tile draw, clearing the depth/stencil buffers didn't matter since I wasn't using any layerDepth to organize what draws on top of what. Now that I'm drawing from lists of common objects rather than tile by tile, it has sped up my draw call considerably but I can't seem to figure out a way to keep the stencil system to mask out the area a door or window will be drawn into a wall. The root of the problem is that when I end a spriteBatch to change the DepthStencilState, it flattens the current RenderTarget and there is no longer any depth sorting for anything drawn further down the line. This means walls always get drawn on top of everything regardless of depth or positioning in the game world and even on top of each other as the stencil has to happen once for every wall that has a door or window. Does anyone know of a way to get around this? To boil it down, I need a way to draw having things sorted by layer depth while also being able to stencil/mask out portions of specific sprites.

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• Generating and rendering not point-like particles on GPU

  - by TravisG

  Specifically I'm talking about particles as seen (for example) in the UE4 dev video here. They're not just points and seem to have a nice shape to them that seems to follow their movement. Is it possible to create these kinds of particles (efficiently) completely on the GPU (perhaps through something like motion? Or is the only (or most efficient) way to just create a small particle texture and render small quads for each particle?

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• Why occlusion is failing sometimes?

  - by cad

  I am rendering two cubes in the space using XNA 4.0 and occlusion only works from certain angles. Here is what I see from the front angle (everything ok) Here is what I see from behind This is my draw method. Cubes are drawn by serverManager and serverManager1 protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); switch (_gameStateFSM.State) { case GameFSMState.GameStateFSM.INTROSCREEN: spriteBatch.Begin(); introscreen.Draw(spriteBatch); spriteBatch.End(); break; case GameFSMState.GameStateFSM.GAME: spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend); // Text screenMessagesManager.Draw(spriteBatch, firstPersonCamera.cameraPosition, fpsHelper.framesPerSecond); // Camera firstPersonCamera.Draw(); // Servers serverManager.Draw(GraphicsDevice, firstPersonCamera.viewMatrix, firstPersonCamera.projMatrix); serverManager1.Draw(GraphicsDevice, firstPersonCamera.viewMatrix, firstPersonCamera.projMatrix); // Room //roomManager.Draw(GraphicsDevice, firstPersonCamera.viewMatrix); spriteBatch.End(); break; case GameFSMState.GameStateFSM.EXITGAME: break; default: break; } base.Draw(gameTime); fpsHelper.IncrementFrameCounter(); } serverManager and serverManager1 are instances of the same class ServerManager that draws a cube. The draw method for ServerManager is: public void Draw(GraphicsDevice graphicsDevice, Matrix viewMatrix, Matrix projectionMatrix) { cubeEffect.World = Matrix.CreateTranslation(modelPosition); // Set the World matrix which defines the position of the cube cubeEffect.View = viewMatrix; // Set the View matrix which defines the camera and what it's looking at cubeEffect.Projection = projectionMatrix; // Enable textures on the Cube Effect. this is necessary to texture the model cubeEffect.TextureEnabled = true; cubeEffect.Texture = cubeTexture; // Enable some pretty lights cubeEffect.EnableDefaultLighting(); // apply the effect and render the cube foreach (EffectPass pass in cubeEffect.CurrentTechnique.Passes) { pass.Apply(); cubeToDraw.RenderToDevice(graphicsDevice); } } Obviously there is something I am doing wrong. Any hint of where to look? (Maybe z-buffer or occlusion tests?)

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• Andengine. Put bullet to pool, when it leaves screen

  - by Ashot

  i'm creating a bullet with physics body. Bullet class (extends Sprite class) has die() method, which unregister physics connector, hide sprite and put it in pool public void die() { Log.d("bulletDie", "See you in hell!"); if (this.isVisible()) { this.setVisible(false); mPhysicsWorld.unregisterPhysicsConnector(physicsConnector); physicsConnector.setUpdatePosition(false); body.setActive(false); this.setIgnoreUpdate(true); bulletsPool.recyclePoolItem(this); } } in onUpdate method of PhysicsConnector i executes die method, when sprite leaves screen physicsConnector = new PhysicsConnector(this,body,true,false) { @Override public void onUpdate(final float pSecondsElapsed) { super.onUpdate(pSecondsElapsed); if (!camera.isRectangularShapeVisible(_bullet)) { Log.d("bulletDie","Dead?"); _bullet.die(); } } }; it works as i expected, but _bullet.die() executes TWICE. what i`m doing wrong and is it right way to hide sprites? here is full code of Bullet class (it is inner class of class that represents player) private class Bullet extends Sprite implements PhysicsConstants { private final Body body; private final PhysicsConnector physicsConnector; private final Bullet _bullet; private int id; public Bullet(float x, float y, ITextureRegion texture, VertexBufferObjectManager vertexBufferObjectManager) { super(x,y,texture,vertexBufferObjectManager); _bullet = this; id = bulletId++; body = PhysicsFactory.createCircleBody(mPhysicsWorld, this, BodyDef.BodyType.DynamicBody, bulletFixture); physicsConnector = new PhysicsConnector(this,body,true,false) { @Override public void onUpdate(final float pSecondsElapsed) { super.onUpdate(pSecondsElapsed); if (!camera.isRectangularShapeVisible(_bullet)) { Log.d("bulletDie","Dead?"); Log.d("bulletDie",id+""); _bullet.die(); } } }; mPhysicsWorld.registerPhysicsConnector(physicsConnector); $this.getParent().attachChild(this); } public void reset() { final float angle = canon.getRotation(); final float x = (float) ((Math.cos(MathUtils.degToRad(angle))*radius) + centerX) / PIXEL_TO_METER_RATIO_DEFAULT; final float y = (float) ((Math.sin(MathUtils.degToRad(angle))*radius) + centerY) / PIXEL_TO_METER_RATIO_DEFAULT; this.setVisible(true); this.setIgnoreUpdate(false); body.setActive(true); mPhysicsWorld.registerPhysicsConnector(physicsConnector); body.setTransform(new Vector2(x,y),0); } public Body getBody() { return body; } public void setLinearVelocity(Vector2 velocity) { body.setLinearVelocity(velocity); } public void die() { Log.d("bulletDie", "See you in hell!"); if (this.isVisible()) { this.setVisible(false); mPhysicsWorld.unregisterPhysicsConnector(physicsConnector); physicsConnector.setUpdatePosition(false); body.setActive(false); this.setIgnoreUpdate(true); bulletsPool.recyclePoolItem(this); } } }

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• Detect click on Triangle and Circle buttons

  - by chr1s89

  How can i detect clicks on a texture (will be a button in my game) that has a form of a triangle or circle. I know only the rectangle solution where u can use the positions + the width/height but this dont work for that because clicks will be detected at the transparent pixels. I heard of pixel-perfect collision is it the right way for this? It would be great if someone can give me a example for such a solution or other.

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• LibGDX - Textures rendering at wrong position

  - by ACluelessGuy

  Update 2: Let me further explain my problem since I think that i didn't make it clear enough: The Y-coordinates on the bottom of my screen should be 0. Instead it is the height of my screen. That means the "higher" i touch/click the screen the less my y-coordinate gets. Above that the origin is not inside my screen, atleast not the 0 y-coordinate. Original post: I'm currently developing a tower defence game for fun by using LibGDX. There are places on my map where the player is or is not allowed to put towers on. So I created different ArrayLists holding rectangles representing a tile on my map. (towerPositions) for(int i = 0; i < map.getLayers().getCount(); i++) { curLay = (TiledMapTileLayer) map.getLayers().get(i); //For all Cells of current Layer for(int k = 0; k < curLay.getWidth(); k++) { for(int j = 0; j < curLay.getHeight(); j++) { curCell = curLay.getCell(k, j); //If there is a actual cell if(curCell != null) { tileWidth = curLay.getTileWidth(); tileHeight = curLay.getTileHeight(); xTileKoord = tileWidth*k; yTileKoord = tileHeight*j; switch(curLay.getName()) { //If layer named "TowersAllowed" picked case "TowersAllowed": towerPositions.add(new Rectangle(xTileKoord, yTileKoord, tileWidth, tileHeight)); // ... AND SO ON If the player clicks on a "allowed" field later on he has the opportunity to build a tower of his coice via a menu. Now here is the problem: The towers render, but they render at wrong position. (They appear really random on the map, no certain pattern for me) for(Rectangle curRect : towerPositions) { if(curRect.contains(xCoord, yCoord)) { //Using a certain tower in this example (left the menu out if(gameControl.createTower("towerXY")) { //RenderObject is just a class holding the Texture and x/y coordinates renderList.add(new RenderObject(new Texture(Gdx.files.internal("TowerXY.png")), curRect.x, curRect.y)); } } } Later on i render it: game.batch.begin(); for(int i = 0; i < renderList.size() ; i++) { game.batch.draw(renderList.get(i).myTexture, renderList.get(i).x, renderList.get(i).y); } game.batch.end(); regards

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• Why distant objects draw in front of close objects?

  - by cad

  I am rendering two cubes in the space using XNA 4.0 and the layering of objects only works from certain angles. Here is what I see from the front angle (everything ok) Here is what I see from behind This is my draw method. Cubes are drawn by serverManager and serverManager1 protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); switch (_gameStateFSM.State) { case GameFSMState.GameStateFSM.INTROSCREEN: spriteBatch.Begin(); introscreen.Draw(spriteBatch); spriteBatch.End(); break; case GameFSMState.GameStateFSM.GAME: spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend); // Text screenMessagesManager.Draw(spriteBatch, firstPersonCamera.cameraPosition, fpsHelper.framesPerSecond); // Camera firstPersonCamera.Draw(); // Servers serverManager.Draw(GraphicsDevice, firstPersonCamera.viewMatrix, firstPersonCamera.projMatrix); serverManager1.Draw(GraphicsDevice, firstPersonCamera.viewMatrix, firstPersonCamera.projMatrix); // Room //roomManager.Draw(GraphicsDevice, firstPersonCamera.viewMatrix); spriteBatch.End(); break; case GameFSMState.GameStateFSM.EXITGAME: break; default: break; } base.Draw(gameTime); fpsHelper.IncrementFrameCounter(); } serverManager and serverManager1 are instances of the same class ServerManager that draws a cube. The draw method for ServerManager is: public void Draw(GraphicsDevice graphicsDevice, Matrix viewMatrix, Matrix projectionMatrix) { cubeEffect.World = Matrix.CreateTranslation(modelPosition); // Set the World matrix which defines the position of the cube cubeEffect.View = viewMatrix; // Set the View matrix which defines the camera and what it's looking at cubeEffect.Projection = projectionMatrix; // Enable textures on the Cube Effect. this is necessary to texture the model cubeEffect.TextureEnabled = true; cubeEffect.Texture = cubeTexture; // Enable some pretty lights cubeEffect.EnableDefaultLighting(); // apply the effect and render the cube foreach (EffectPass pass in cubeEffect.CurrentTechnique.Passes) { pass.Apply(); cubeToDraw.RenderToDevice(graphicsDevice); } } Obviously there is something I am doing wrong. Any hint of where to look? (Maybe z-buffer or occlusion tests?)

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• Where can I find free simple 3D models? [duplicate]

  - by fibo-Nacci

  This question is an exact duplicate of: What are good sites that provide free media resources for hobby game development? [closed] I'm learning OpenGL. Unfortunately can't create 3D models, but I would like to write some really simple games, to improve my programming skills. I need some really basic .obj file, which has one bmp, or jpeg texture. Where can I download some for free? Thanks in advance,

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• How do I render from one render target to another?

  - by Chaotikmind

  I have two render targets: a fake backbuffer; a special render target where I do all my rendering. a light render target; where I render my light fx. I'm sure I'm rendering correctly on both. The problem arises when I overlay the light render target onto the fake backbuffer by drawing a quad covering it: DxEngine.DrawSprite(0.0f, 0.0f, 0.0f, (float)DxEngine.GetWidth(), (float)DxEngine.GetHeight(), 0xFFFFFFFF, LightSurface->GetTexture()); Regardless of what's in the light target, nothing is rendered onto the other target. I tried clearing the light target with full-white or full-black, but still get nothing. Fake backbuffer created with Direct3dDev->CreateTexture(Width, Height, 1, D3DUSAGE_RENDERTARGET, D3DFMT_X8R8G8B8, D3DPOOL_DEFAULT, &Texture, nullptr); Light render target created with Direct3dDev->CreateTexture(Width, Height, 1, D3DUSAGE_RENDERTARGET, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &Texture, nullptr); I also tried to create both with D3DFMT_A8R8G8B8, again without difference. Both targets have the same width and height. Only the fixed pipeline is used DirectX setup for rendering : Direct3dDev->SetSamplerState(0, D3DSAMP_MINFILTER, D3DTEXF_LINEAR ); Direct3dDev->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR ); Direct3dDev->SetSamplerState(0, D3DSAMP_MIPFILTER, D3DTEXF_NONE ); Direct3dDev->SetSamplerState(0, D3DSAMP_ADDRESSU, D3DTADDRESS_WRAP ); Direct3dDev->SetSamplerState(0, D3DSAMP_ADDRESSV, D3DTADDRESS_WRAP ); Direct3dDev->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE); Direct3dDev->SetRenderState(D3DRS_LIGHTING, false); Direct3dDev->SetRenderState(D3DRS_ZENABLE, D3DZB_TRUE); Direct3dDev->SetRenderState(D3DRS_ZWRITEENABLE,D3DZB_TRUE); Direct3dDev->SetRenderState(D3DRS_ZFUNC,D3DCMP_LESSEQUAL); Direct3dDev->SetRenderState(D3DRS_ALPHABLENDENABLE, true ); Direct3dDev->SetRenderState(D3DRS_ALPHAREF, 0x00000000ul); Direct3dDev->SetRenderState(D3DRS_ALPHATESTENABLE, true); Direct3dDev->SetRenderState(D3DRS_ALPHAFUNC,D3DCMP_GREATER); Direct3dDev->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA ); Direct3dDev->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA ); Direct3dDev->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE); Direct3dDev->SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_DIFFUSE); Direct3dDev->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_MODULATE); Direct3dDev->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE); Direct3dDev->SetTextureStageState(0, D3DTSS_ALPHAARG2, D3DTA_DIFFUSE); Direct3dDev->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_MODULATE); Direct3dDev->SetTextureStageState(0, D3DTSS_RESULTARG, D3DTA_CURRENT); Direct3dDev->SetTextureStageState(0, D3DTSS_TEXCOORDINDEX, D3DTSS_TCI_PASSTHRU); //ensure the first stage is not used for now Direct3dDev->SetTextureStageState(1, D3DTSS_COLOROP, D3DTOP_DISABLE); How can I do this right?

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• "domain crashed" when creating new Xen instance

  - by user47650

  I have downloaded a Xen virtual machine image from the appscale project, and I am trying to start it up. However once I run the command; xm create -c -f xen.conf The instance immediately crashes and provides no console output. however it produces logs that I have posted below. but this is the error; [2011-03-01 12:34:03 xend.XendDomainInfo 3580] WARNING (XendDomainInfo:1178) Domain has crashed: name=appscale-1.4b id=10. I have managed to mount the root.img file locally and verify that it is actually an ext3 file system. I am running Xen 3.0.3 that is a stock RPM from the CentOS 5 repos; # rpm -qa | grep -i xen xen-libs-3.0.3-105.el5_5.5 xen-3.0.3-105.el5_5.5 xen-libs-3.0.3-105.el5_5.5 kernel-xen-2.6.18-194.32.1.el5 any suggestions on how to proceed with troubleshooting? (i am a newbie to Xen) so far I have enabled console logging, but the log file is empty. ==> domain-builder-ng.log <== xc_dom_allocate: cmdline=" ip=:1.2.3.4::::eth0:dhcp root=/dev/sda1 ro xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console", features="" xc_dom_kernel_file: filename="/boot/vmlinuz-2.6.27-7-server" xc_dom_malloc_filemap : 2284 kB xc_dom_ramdisk_file: filename="/boot/initrd.img-2.6.27-7-server" xc_dom_malloc_filemap : 9005 kB xc_dom_boot_xen_init: ver 3.1, caps xen-3.0-x86_64 xen-3.0-x86_32p xc_dom_parse_image: called xc_dom_find_loader: trying ELF-generic loader ... failed xc_dom_find_loader: trying Linux bzImage loader ... xc_dom_malloc : 9875 kB xc_dom_do_gunzip: unzip ok, 0x234bb2 -> 0x9a4de0 OK elf_parse_binary: phdr: paddr=0x200000 memsz=0x447000 elf_parse_binary: phdr: paddr=0x647000 memsz=0xab888 elf_parse_binary: phdr: paddr=0x6f3000 memsz=0x908 elf_parse_binary: phdr: paddr=0x6f4000 memsz=0x1c2f9c elf_parse_binary: memory: 0x200000 -> 0x8b6f9c elf_xen_parse_note: GUEST_OS = "linux" elf_xen_parse_note: GUEST_VERSION = "2.6" elf_xen_parse_note: XEN_VERSION = "xen-3.0" elf_xen_parse_note: VIRT_BASE = 0xffffffff80000000 elf_xen_parse_note: ENTRY = 0xffffffff8071e200 elf_xen_parse_note: HYPERCALL_PAGE = 0xffffffff80209000 elf_xen_parse_note: FEATURES = "!writable_page_tables|pae_pgdir_above_4gb" elf_xen_parse_note: PAE_MODE = "yes" elf_xen_parse_note: LOADER = "generic" elf_xen_parse_note: unknown xen elf note (0xd) elf_xen_parse_note: SUSPEND_CANCEL = 0x1 elf_xen_parse_note: HV_START_LOW = 0xffff800000000000 elf_xen_parse_note: PADDR_OFFSET = 0x0 elf_xen_addr_calc_check: addresses: virt_base = 0xffffffff80000000 elf_paddr_offset = 0x0 virt_offset = 0xffffffff80000000 virt_kstart = 0xffffffff80200000 virt_kend = 0xffffffff808b6f9c virt_entry = 0xffffffff8071e200 xc_dom_parse_elf_kernel: xen-3.0-x86_64: 0xffffffff80200000 -> 0xffffffff808b6f9c xc_dom_mem_init: mem 1024 MB, pages 0x40000 pages, 4k each xc_dom_mem_init: 0x40000 pages xc_dom_boot_mem_init: called x86_compat: guest xen-3.0-x86_64, address size 64 xc_dom_malloc : 2048 kB ==> xend.log <== [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:957) Dev 0 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:957) Dev 0 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:957) Dev 0 still active, looping... [2011-03-01 12:34:02 xend.XendDomainInfo 3580] INFO (XendDomainInfo:957) Dev 0 still active, looping... [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2114) UUID Created: True [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2115) Devices to release: [], domid = 9 [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2127) Releasing PVFB backend devices ... [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:207) XendDomainInfo.create(['domain', ['domid', 9], ['uuid', 'd5f22dd4-8dc2-f51f-84e9-eea7d71ea1d0'], ['vcpus', 1], ['vcpu_avail', 1], ['cpu_cap', 0], ['cpu_weight', 256], ['memory', 1024], ['shadow_memory', 0], ['maxmem', 1024], ['features', ''], ['name', 'appscale-1.4b'], ['on_poweroff', 'destroy'], ['on_reboot', 'restart'], ['on_crash', 'restart'], ['image', ['linux', ['kernel', '/boot/vmlinuz-2.6.27-7-server'], ['ramdisk', '/boot/initrd.img-2.6.27-7-server'], ['ip', ':1.2.3.4::::eth0:dhcp'], ['root', '/dev/sda1 ro'], ['args', 'xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console']]], ['cpus', []], ['device', ['vif', ['backend', 0], ['script', 'vif-bridge'], ['mac', '00:16:3B:72:10:E4']]], ['device', ['vbd', ['backend', 0], ['dev', 'sda1:disk'], ['uname', 'file:/local/xen/domains/appscale1.4/root.img'], ['mode', 'w']]], ['state', '----c-'], ['shutdown_reason', 'crash'], ['cpu_time', 0.000339131], ['online_vcpus', 1], ['up_time', '0.952092885971'], ['start_time', '1299011639.92'], ['store_mfn', 1169289], ['console_mfn', 1169288]]) [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:329) parseConfig: config is ['domain', ['domid', 9], ['uuid', 'd5f22dd4-8dc2-f51f-84e9-eea7d71ea1d0'], ['vcpus', 1], ['vcpu_avail', 1], ['cpu_cap', 0], ['cpu_weight', 256], ['memory', 1024], ['shadow_memory', 0], ['maxmem', 1024], ['features', ''], ['name', 'appscale-1.4b'], ['on_poweroff', 'destroy'], ['on_reboot', 'restart'], ['on_crash', 'restart'], ['image', ['linux', ['kernel', '/boot/vmlinuz-2.6.27-7-server'], ['ramdisk', '/boot/initrd.img-2.6.27-7-server'], ['ip', ':1.2.3.4::::eth0:dhcp'], ['root', '/dev/sda1 ro'], ['args', 'xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console']]], ['cpus', []], ['device', ['vif', ['backend', 0], ['script', 'vif-bridge'], ['mac', '00:16:3B:72:10:E4']]], ['device', ['vbd', ['backend', 0], ['dev', 'sda1:disk'], ['uname', 'file:/local/xen/domains/appscale1.4/root.img'], ['mode', 'w']]], ['state', '----c-'], ['shutdown_reason', 'crash'], ['cpu_time', 0.000339131], ['online_vcpus', 1], ['up_time', '0.952092885971'], ['start_time', '1299011639.92'], ['store_mfn', 1169289], ['console_mfn', 1169288]] [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:446) parseConfig: result is {'features': '', 'image': ['linux', ['kernel', '/boot/vmlinuz-2.6.27-7-server'], ['ramdisk', '/boot/initrd.img-2.6.27-7-server'], ['ip', ':1.2.3.4::::eth0:dhcp'], ['root', '/dev/sda1 ro'], ['args', 'xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console']], 'cpus': [], 'vcpu_avail': 1, 'backend': [], 'uuid': 'd5f22dd4-8dc2-f51f-84e9-eea7d71ea1d0', 'on_reboot': 'restart', 'cpu_weight': 256.0, 'memory': 1024, 'cpu_cap': 0, 'localtime': None, 'timer_mode': None, 'start_time': 1299011639.9200001, 'on_poweroff': 'destroy', 'on_crash': 'restart', 'device': [('vif', ['vif', ['backend', 0], ['script', 'vif-bridge'], ['mac', '00:16:3B:72:10:E4']]), ('vbd', ['vbd', ['backend', 0], ['dev', 'sda1:disk'], ['uname', 'file:/local/xen/domains/appscale1.4/root.img'], ['mode', 'w']])], 'bootloader': None, 'maxmem': 1024, 'shadow_memory': 0, 'name': 'appscale-1.4b', 'bootloader_args': None, 'vcpus': 1, 'cpu': None} [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:1784) XendDomainInfo.construct: None [2011-03-01 12:34:02 xend 3580] DEBUG (balloon:145) Balloon: 3034420 KiB free; need 4096; done. [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:1953) XendDomainInfo.initDomain: 10 256.0 [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:1994) _initDomain:shadow_memory=0x0, maxmem=0x400, memory=0x400. [2011-03-01 12:34:02 xend 3580] DEBUG (balloon:145) Balloon: 3034412 KiB free; need 1048576; done. [2011-03-01 12:34:02 xend 3580] INFO (image:139) buildDomain os=linux dom=10 vcpus=1 [2011-03-01 12:34:02 xend 3580] DEBUG (image:208) domid = 10 [2011-03-01 12:34:02 xend 3580] DEBUG (image:209) memsize = 1024 [2011-03-01 12:34:02 xend 3580] DEBUG (image:210) image = /boot/vmlinuz-2.6.27-7-server [2011-03-01 12:34:02 xend 3580] DEBUG (image:211) store_evtchn = 1 [2011-03-01 12:34:02 xend 3580] DEBUG (image:212) console_evtchn = 2 [2011-03-01 12:34:02 xend 3580] DEBUG (image:213) cmdline = ip=:1.2.3.4::::eth0:dhcp root=/dev/sda1 ro xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console [2011-03-01 12:34:02 xend 3580] DEBUG (image:214) ramdisk = /boot/initrd.img-2.6.27-7-server [2011-03-01 12:34:02 xend 3580] DEBUG (image:215) vcpus = 1 [2011-03-01 12:34:02 xend 3580] DEBUG (image:216) features = ==> domain-builder-ng.log <== xc_dom_build_image: called xc_dom_alloc_segment: kernel : 0xffffffff80200000 -> 0xffffffff808b7000 (pfn 0x200 + 0x6b7 pages) xc_dom_pfn_to_ptr: domU mapping: pfn 0x200+0x6b7 at 0x2aaaab5f6000 elf_load_binary: phdr 0 at 0x0x2aaaab5f6000 -> 0x0x2aaaaba3d000 elf_load_binary: phdr 1 at 0x0x2aaaaba3d000 -> 0x0x2aaaabae8888 elf_load_binary: phdr 2 at 0x0x2aaaabae9000 -> 0x0x2aaaabae9908 elf_load_binary: phdr 3 at 0x0x2aaaabaea000 -> 0x0x2aaaabb9a004 xc_dom_alloc_segment: ramdisk : 0xffffffff808b7000 -> 0xffffffff82382000 (pfn 0x8b7 + 0x1acb pages) xc_dom_malloc : 160 kB xc_dom_pfn_to_ptr: domU mapping: pfn 0x8b7+0x1acb at 0x2aaab0000000 xc_dom_do_gunzip: unzip ok, 0x8cb5e7 -> 0x1aca210 xc_dom_alloc_segment: phys2mach : 0xffffffff82382000 -> 0xffffffff82582000 (pfn 0x2382 + 0x200 pages) xc_dom_pfn_to_ptr: domU mapping: pfn 0x2382+0x200 at 0x2aaab1acb000 xc_dom_alloc_page : start info : 0xffffffff82582000 (pfn 0x2582) xc_dom_alloc_page : xenstore : 0xffffffff82583000 (pfn 0x2583) xc_dom_alloc_page : console : 0xffffffff82584000 (pfn 0x2584) nr_page_tables: 0x0000ffffffffffff/48: 0xffff000000000000 -> 0xffffffffffffffff, 1 table(s) nr_page_tables: 0x0000007fffffffff/39: 0xffffff8000000000 -> 0xffffffffffffffff, 1 table(s) nr_page_tables: 0x000000003fffffff/30: 0xffffffff80000000 -> 0xffffffffbfffffff, 1 table(s) nr_page_tables: 0x00000000001fffff/21: 0xffffffff80000000 -> 0xffffffff827fffff, 20 table(s) xc_dom_alloc_segment: page tables : 0xffffffff82585000 -> 0xffffffff8259c000 (pfn 0x2585 + 0x17 pages) xc_dom_pfn_to_ptr: domU mapping: pfn 0x2585+0x17 at 0x2aaab1ccb000 xc_dom_alloc_page : boot stack : 0xffffffff8259c000 (pfn 0x259c) xc_dom_build_image : virt_alloc_end : 0xffffffff8259d000 xc_dom_build_image : virt_pgtab_end : 0xffffffff82800000 xc_dom_boot_image: called arch_setup_bootearly: doing nothing xc_dom_compat_check: supported guest type: xen-3.0-x86_64 <= matches xc_dom_compat_check: supported guest type: xen-3.0-x86_32p xc_dom_update_guest_p2m: dst 64bit, pages 0x40000 clear_page: pfn 0x2584, mfn 0x11d788 clear_page: pfn 0x2583, mfn 0x11d789 xc_dom_pfn_to_ptr: domU mapping: pfn 0x2582+0x1 at 0x2aaab1ce2000 start_info_x86_64: called setup_hypercall_page: vaddr=0xffffffff80209000 pfn=0x209 domain builder memory footprint allocated malloc : 12139 kB anon mmap : 0 bytes mapped file mmap : 11289 kB domU mmap : 35 MB arch_setup_bootlate: shared_info: pfn 0x0, mfn 0xd6fe1 shared_info_x86_64: called vcpu_x86_64: called vcpu_x86_64: cr3: pfn 0x2585 mfn 0x11d787 launch_vm: called, ctxt=0x97b21f8 xc_dom_release: called ==> xend.log <== [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:114) DevController: writing {'mac': '00:16:3B:72:10:E4', 'handle': '0', 'protocol': 'x86_64-abi', 'backend-id': '0', 'state': '1', 'backend': '/local/domain/0/backend/vif/10/0'} to /local/domain/10/device/vif/0. [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:116) DevController: writing {'domain': 'appscale-1.4b', 'handle': '0', 'script': '/etc/xen/scripts/vif-bridge', 'state': '1', 'frontend': '/local/domain/10/device/vif/0', 'mac': '00:16:3B:72:10:E4', 'online': '1', 'frontend-id': '10'} to /local/domain/0/backend/vif/10/0. [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:634) Checking for duplicate for uname: /local/xen/domains/appscale1.4/root.img [file:/local/xen/domains/appscale1.4/root.img], dev: sda1:disk, mode: w [2011-03-01 12:34:02 xend 3580] DEBUG (blkif:27) exception looking up device number for sda1:disk: [Errno 2] No such file or directory: '/dev/sda1:disk' [2011-03-01 12:34:02 xend 3580] DEBUG (blkif:27) exception looking up device number for sda1: [Errno 2] No such file or directory: '/dev/sda1' [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:114) DevController: writing {'virtual-device': '2049', 'device-type': 'disk', 'protocol': 'x86_64-abi', 'backend-id': '0', 'state': '1', 'backend': '/local/domain/0/backend/vbd/10/2049'} to /local/domain/10/device/vbd/2049. [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:116) DevController: writing {'domain': 'appscale-1.4b', 'frontend': '/local/domain/10/device/vbd/2049', 'format': 'raw', 'dev': 'sda1', 'state': '1', 'params': '/local/xen/domains/appscale1.4/root.img', 'mode': 'w', 'online': '1', 'frontend-id': '10', 'type': 'file'} to /local/domain/0/backend/vbd/10/2049. [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:993) Storing VM details: {'shadow_memory': '0', 'uuid': 'd5f22dd4-8dc2-f51f-84e9-eea7d71ea1d0', 'on_reboot': 'restart', 'start_time': '1299011642.74', 'on_poweroff': 'destroy', 'name': 'appscale-1.4b', 'xend/restart_count': '0', 'vcpus': '1', 'vcpu_avail': '1', 'memory': '1024', 'on_crash': 'restart', 'image': "(linux (kernel /boot/vmlinuz-2.6.27-7-server) (ramdisk /boot/initrd.img-2.6.27-7-server) (ip :1.2.3.4::::eth0:dhcp) (root '/dev/sda1 ro') (args 'xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console'))", 'maxmem': '1024'} [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:1028) Storing domain details: {'console/ring-ref': '1169288', 'console/port': '2', 'name': 'appscale-1.4b', 'console/limit': '1048576', 'vm': '/vm/d5f22dd4-8dc2-f51f-84e9-eea7d71ea1d0', 'domid': '10', 'cpu/0/availability': 'online', 'memory/target': '1048576', 'store/ring-ref': '1169289', 'store/port': '1'} [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:158) Waiting for devices vif. [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:164) Waiting for 0. [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:1250) XendDomainInfo.handleShutdownWatch [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:509) hotplugStatusCallback /local/domain/0/backend/vif/10/0/hotplug-status. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:509) hotplugStatusCallback /local/domain/0/backend/vif/10/0/hotplug-status. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:523) hotplugStatusCallback 1. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices usb. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices vbd. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:164) Waiting for 2049. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:509) hotplugStatusCallback /local/domain/0/backend/vbd/10/2049/hotplug-status. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:509) hotplugStatusCallback /local/domain/0/backend/vbd/10/2049/hotplug-status. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:523) hotplugStatusCallback 1. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices irq. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices vkbd. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices vfb. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices pci. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices ioports. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices tap. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices vtpm. [2011-03-01 12:34:03 xend.XendDomainInfo 3580] WARNING (XendDomainInfo:1178) Domain has crashed: name=appscale-1.4b id=10. [2011-03-01 12:34:03 xend.XendDomainInfo 3580] ERROR (XendDomainInfo:2654) VM appscale-1.4b restarting too fast (2.275545 seconds since the last restart). Refusing to restart to avoid loops. [2011-03-01 12:34:03 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2189) XendDomainInfo.destroy: domid=10 ==> xen-hotplug.log <== Nothing to flush. ==> xend.log <== [2011-03-01 12:34:03 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:03 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:03 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:03 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:03 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:03 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2114) UUID Created: True [2011-03-01 12:34:03 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2115) Devices to release: [], domid = 10 [2011-03-01 12:34:03 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2127) Releasing PVFB backend devices ... And this is the xen.conf file that I am using; # cat xen.conf # Configuration file for the Xen instance AppScale, created # bn VMBuilder kernel = '/boot/vmlinuz-2.6.27-7-server' ramdisk = '/boot/initrd.img-2.6.27-7-server' memory = 1024 vcpus = 1 root = '/dev/sda1 ro' disk = [ 'file:/local/xen/domains/appscale1.4/root.img,sda1,w', ] name = 'appscale-1.4b' dhcp = 'dhcp' vif = [ 'mac=00:16:3B:72:10:E4' ] on_poweroff = 'destroy' on_reboot = 'restart' on_crash = 'restart' extra = 'xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console'

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• Differences Between NHibernate and Entity Framework

  - by Ricardo Peres

  Introduction NHibernate and Entity Framework are two of the most popular O/RM frameworks on the .NET world. Although they share some functionality, there are some aspects on which they are quite different. This post will describe this differences and will hopefully help you get started with the one you know less. Mind you, this is a personal selection of features to compare, it is by no way an exhaustive list. History First, a bit of history. NHibernate is an open-source project that was first ported from Java’s venerable Hibernate framework, one of the first O/RM frameworks, but nowadays it is not tied to it, for example, it has .NET specific features, and has evolved in different ways from those of its Java counterpart. Current version is 3.3, with 3.4 on the horizon. It currently targets .NET 3.5, but can be used as well in .NET 4, it only makes no use of any of its specific functionality. You can find its home page at NHForge. Entity Framework 1 came out with .NET 3.5 and is now on its second major version, despite being version 4. Code First sits on top of it and but came separately and will also continue to be released out of line with major .NET distributions. It is currently on version 4.3.1 and version 5 will be released together with .NET Framework 4.5. All versions will target the current version of .NET, at the time of their release. Its home location is located at MSDN. Architecture In NHibernate, there is a separation between the Unit of Work and the configuration and model instances. You start off by creating a Configuration object, where you specify all global NHibernate settings such as the database and dialect to use, the batch sizes, the mappings, etc, then you build an ISessionFactory from it. The ISessionFactory holds model and metadata that is tied to a particular database and to the settings that came from the Configuration object, and, there will typically be only one instance of each in a process. Finally, you create instances of ISession from the ISessionFactory, which is the NHibernate representation of the Unit of Work and Identity Map. This is a lightweight object, it basically opens and closes a database connection as required and keeps track of the entities associated with it. ISession objects are cheap to create and dispose, because all of the model complexity is stored in the ISessionFactory and Configuration objects. As for Entity Framework, the ObjectContext/DbContext holds the configuration, model and acts as the Unit of Work, holding references to all of the known entity instances. This class is therefore not lightweight as its NHibernate counterpart and it is not uncommon to see examples where an instance is cached on a field. Mappings Both NHibernate and Entity Framework (Code First) support the use of POCOs to represent entities, no base classes are required (or even possible, in the case of NHibernate). As for mapping to and from the database, NHibernate supports three types of mappings: XML-based, which have the advantage of not tying the entity classes to a particular O/RM; the XML files can be deployed as files on the file system or as embedded resources in an assembly; Attribute-based, for keeping both the entities and database details on the same place at the expense of polluting the entity classes with NHibernate-specific attributes; Strongly-typed code-based, which allows dynamic creation of the model and strongly typing it, so that if, for example, a property name changes, the mapping will also be updated. Entity Framework can use: Attribute-based (although attributes cannot express all of the available possibilities – for example, cascading); Strongly-typed code mappings. Database Support With NHibernate you can use mostly any database you want, including: SQL Server; SQL Server Compact; SQL Server Azure; Oracle; DB2; PostgreSQL; MySQL; Sybase Adaptive Server/SQL Anywhere; Firebird; SQLLite; Informix; Any through OLE DB; Any through ODBC. Out of the box, Entity Framework only supports SQL Server, but a number of providers exist, both free and commercial, for some of the most used databases, such as Oracle and MySQL. See a list here. Inheritance Strategies Both NHibernate and Entity Framework support the three canonical inheritance strategies: Table Per Type Hierarchy (Single Table Inheritance), Table Per Type (Class Table Inheritance) and Table Per Concrete Type (Concrete Table Inheritance). Associations Regarding associations, both support one to one, one to many and many to many. However, NHibernate offers far more collection types: Bags of entities or values: unordered, possibly with duplicates; Lists of entities or values: ordered, indexed by a number column; Maps of entities or values: indexed by either an entity or any value; Sets of entities or values: unordered, no duplicates; Arrays of entities or values: indexed, immutable. Querying NHibernate exposes several querying APIs: LINQ is probably the most used nowadays, and really does not need to be introduced; Hibernate Query Language (HQL) is a database-agnostic, object-oriented SQL-alike language that exists since NHibernate’s creation and still offers the most advanced querying possibilities; well suited for dynamic queries, even if using string concatenation; Criteria API is an implementation of the Query Object pattern where you create a semi-abstract conceptual representation of the query you wish to execute by means of a class model; also a good choice for dynamic querying; Query Over offers a similar API to Criteria, but using strongly-typed LINQ expressions instead of strings; for this, although more refactor-friendlier that Criteria, it is also less suited for dynamic queries; SQL, including stored procedures, can also be used; Integration with Lucene.NET indexer is available. As for Entity Framework: LINQ to Entities is fully supported, and its implementation is considered very complete; it is the API of choice for most developers; Entity-SQL, HQL’s counterpart, is also an object-oriented, database-independent querying language that can be used for dynamic queries; SQL, of course, is also supported. Caching Both NHibernate and Entity Framework, of course, feature first-level cache. NHibernate also supports a second-level cache, that can be used among multiple ISessionFactorys, even in different processes/machines: Hashtable (in-memory); SysCache (uses ASP.NET as the cache provider); SysCache2 (same as above but with support for SQL Server SQL Dependencies); Prevalence; SharedCache; Memcached; Redis; NCache; Appfabric Caching. Out of the box, Entity Framework does not have any second-level cache mechanism, however, there are some public samples that show how we can add this. ID Generators NHibernate supports different ID generation strategies, coming from the database and otherwise: Identity (for SQL Server, MySQL, and databases who support identity columns); Sequence (for Oracle, PostgreSQL, and others who support sequences); Trigger-based; HiLo; Sequence HiLo (for databases that support sequences); Several GUID flavors, both in GUID as well as in string format; Increment (for single-user uses); Assigned (must know what you’re doing); Sequence-style (either uses an actual sequence or a single-column table); Table of ids; Pooled (similar to HiLo but stores high values in a table); Native (uses whatever mechanism the current database supports, identity or sequence). Entity Framework only supports: Identity generation; GUIDs; Assigned values. Properties NHibernate supports properties of entity types (one to one or many to one), collections (one to many or many to many) as well as scalars and enumerations. It offers a mechanism for having complex property types generated from the database, which even include support for querying. It also supports properties originated from SQL formulas. Entity Framework only supports scalars, entity types and collections. Enumerations support will come in the next version. Events and Interception NHibernate has a very rich event model, that exposes more than 20 events, either for synchronous pre-execution or asynchronous post-execution, including: Pre/Post-Load; Pre/Post-Delete; Pre/Post-Insert; Pre/Post-Update; Pre/Post-Flush. It also features interception of class instancing and SQL generation. As for Entity Framework, only two events exist: ObjectMaterialized (after loading an entity from the database); SavingChanges (before saving changes, which include deleting, inserting and updating). Tracking Changes For NHibernate as well as Entity Framework, all changes are tracked by their respective Unit of Work implementation. Entities can be attached and detached to it, Entity Framework does, however, also support self-tracking entities. Optimistic Concurrency Control NHibernate supports all of the imaginable scenarios: SQL Server’s ROWVERSION; Oracle’s ORA_ROWSCN; A column containing date and time; A column containing a version number; All/dirty columns comparison. Entity Framework is more focused on Entity Framework, so it only supports: SQL Server’s ROWVERSION; Comparing all/some columns. Batching NHibernate has full support for insertion batching, but only if the ID generator in use is not database-based (for example, it cannot be used with Identity), whereas Entity Framework has no batching at all. Cascading Both support cascading for collections and associations: when an entity is deleted, their conceptual children are also deleted. NHibernate also offers the possibility to set the foreign key column on children to NULL instead of removing them. Flushing Changes NHibernate’s ISession has a FlushMode property that can have the following values: Auto: changes are sent to the database when necessary, for example, if there are dirty instances of an entity type, and a query is performed against this entity type, or if the ISession is being disposed; Commit: changes are sent when committing the current transaction; Never: changes are only sent when explicitly calling Flush(). As for Entity Framework, changes have to be explicitly sent through a call to AcceptAllChanges()/SaveChanges(). Lazy Loading NHibernate supports lazy loading for Associated entities (one to one, many to one); Collections (one to many, many to many); Scalar properties (thing of BLOBs or CLOBs). Entity Framework only supports lazy loading for: Associated entities; Collections. Generating and Updating the Database Both NHibernate and Entity Framework Code First (with the Migrations API) allow creating the database model from the mapping and updating it if the mapping changes. Extensibility As you can guess, NHibernate is far more extensible than Entity Framework. Basically, everything can be extended, from ID generation, to LINQ to SQL transformation, HQL native SQL support, custom column types, custom association collections, SQL generation, supported databases, etc. With Entity Framework your options are more limited, at least, because practically no information exists as to what can be extended/changed. It features a provider model that can be extended to support any database. Integration With Other Microsoft APIs and Tools When it comes to integration with Microsoft technologies, it will come as no surprise that Entity Framework offers the best support. For example, the following technologies are fully supported: ASP.NET (through the EntityDataSource); ASP.NET Dynamic Data; WCF Data Services; WCF RIA Services; Visual Studio (through the integrated designer). Documentation This is another point where Entity Framework is superior: NHibernate lacks, for starters, an up to date API reference synchronized with its current version. It does have a community mailing list, blogs and wikis, although not much used. Entity Framework has a number of resources on MSDN and, of course, several forums and discussion groups exist. Conclusion Like I said, this is a personal list. I may come as a surprise to some that Entity Framework is so behind NHibernate in so many aspects, but it is true that NHibernate is much older and, due to its open-source nature, is not tied to product-specific timeframes and can thus evolve much more rapidly. I do like both, and I chose whichever is best for the job I have at hands. I am looking forward to the changes in EF5 which will add significant value to an already interesting product. So, what do you think? Did I forget anything important or is there anything else worth talking about? Looking forward for your comments!

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• Coherence - How to develop a custom push replication publisher

  - by cosmin.tudor(at)oracle.com

  CoherencePushReplicationDB.zipIn the example bellow I'm describing a way of developing a custom push replication publisher that publishes data to a database via JDBC. This example can be easily changed to publish data to other receivers (JMS,...) by performing changes to step 2 and small changes to step 3, steps that are presented bellow. I've used Eclipse as the development tool. To develop a custom push replication publishers we will need to go through 6 steps: Step 1: Create a custom publisher scheme class Step 2: Create a custom publisher class that should define what the publisher is doing. Step 3: Create a class data is performing the actions (publish to JMS, DB, etc ) for the custom publisher. Step 4: Register the new publisher against a ContentHandler. Step 5: Add the new custom publisher in the cache configuration file. Step 6: Add the custom publisher scheme class to the POF configuration file. All these steps are detailed bellow. The coherence project is attached and conclusions are presented at the end. Step 1: In the Coherence Eclipse project create a class called CustomPublisherScheme that should implement com.oracle.coherence.patterns.pushreplication.publishers.AbstractPublisherScheme. In this class define the elements of the custom-publisher-scheme element. For instance for a CustomPublisherScheme that looks like that: <sync:publisher> <sync:publisher-name>Active2-JDBC-Publisher</sync:publisher-name> <sync:publisher-scheme> <sync:custom-publisher-scheme> <sync:jdbc-string>jdbc:oracle:thin:@machine-name:1521:XE</sync:jdbc-string> <sync:username>hr</sync:username> <sync:password>hr</sync:password> </sync:custom-publisher-scheme> </sync:publisher-scheme> </sync:publisher> the code is: package com.oracle.coherence; import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import com.oracle.coherence.patterns.pushreplication.Publisher; import com.oracle.coherence.configuration.Configurable; import com.oracle.coherence.configuration.Mandatory; import com.oracle.coherence.configuration.Property; import com.oracle.coherence.configuration.parameters.ParameterScope; import com.oracle.coherence.environment.Environment; import com.tangosol.io.pof.PofReader; import com.tangosol.io.pof.PofWriter; import com.tangosol.util.ExternalizableHelper; @Configurable public class CustomPublisherScheme extends com.oracle.coherence.patterns.pushreplication.publishers.AbstractPublisherScheme { /** * */ private static final long serialVersionUID = 1L; private String jdbcString; private String username; private String password; public String getJdbcString() { return this.jdbcString; } @Property("jdbc-string") @Mandatory public void setJdbcString(String jdbcString) { this.jdbcString = jdbcString; } public String getUsername() { return username; } @Property("username") @Mandatory public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } @Property("password") @Mandatory public void setPassword(String password) { this.password = password; } public Publisher realize(Environment environment, ClassLoader classLoader, ParameterScope parameterScope) { return new CustomPublisher(getJdbcString(), getUsername(), getPassword()); } public void readExternal(DataInput in) throws IOException { super.readExternal(in); this.jdbcString = ExternalizableHelper.readSafeUTF(in); this.username = ExternalizableHelper.readSafeUTF(in); this.password = ExternalizableHelper.readSafeUTF(in); } public void writeExternal(DataOutput out) throws IOException { super.writeExternal(out); ExternalizableHelper.writeSafeUTF(out, this.jdbcString); ExternalizableHelper.writeSafeUTF(out, this.username); ExternalizableHelper.writeSafeUTF(out, this.password); } public void readExternal(PofReader reader) throws IOException { super.readExternal(reader); this.jdbcString = reader.readString(100); this.username = reader.readString(101); this.password = reader.readString(102); } public void writeExternal(PofWriter writer) throws IOException { super.writeExternal(writer); writer.writeString(100, this.jdbcString); writer.writeString(101, this.username); writer.writeString(102, this.password); } } Step 2: Define what the CustomPublisher should basically do by creating a new java class called CustomPublisher that implements com.oracle.coherence.patterns.pushreplication.Publisher package com.oracle.coherence; import com.oracle.coherence.patterns.pushreplication.EntryOperation; import com.oracle.coherence.patterns.pushreplication.Publisher; import com.oracle.coherence.patterns.pushreplication.exceptions.PublisherNotReadyException; import java.io.BufferedWriter; import java.util.Iterator; public class CustomPublisher implements Publisher { private String jdbcString; private String username; private String password; private transient BufferedWriter bufferedWriter; public CustomPublisher() { } public CustomPublisher(String jdbcString, String username, String password) { this.jdbcString = jdbcString; this.username = username; this.password = password; this.bufferedWriter = null; } public String getJdbcString() { return this.jdbcString; } public String getUsername() { return username; } public String getPassword() { return password; } public void publishBatch(String cacheName, String publisherName, Iterator<EntryOperation> entryOperations) { DatabasePersistence databasePersistence = new DatabasePersistence( jdbcString, username, password); while (entryOperations.hasNext()) { EntryOperation entryOperation = (EntryOperation) entryOperations .next(); databasePersistence.databasePersist(entryOperation); } } public void start(String cacheName, String publisherName) throws PublisherNotReadyException { System.err .printf("Started: Custom JDBC Publisher for Cache %s with Publisher %s\n", new Object[] { cacheName, publisherName }); } public void stop(String cacheName, String publisherName) { System.err .printf("Stopped: Custom JDBC Publisher for Cache %s with Publisher %s\n", new Object[] { cacheName, publisherName }); } } In the publishBatch method from above we inform the publisher that he is supposed to persist data to a database: DatabasePersistence databasePersistence = new DatabasePersistence( jdbcString, username, password); while (entryOperations.hasNext()) { EntryOperation entryOperation = (EntryOperation) entryOperations .next(); databasePersistence.databasePersist(entryOperation); } Step 3: The class that deals with the persistence is a very basic one that uses JDBC to perform inserts/updates against a database. package com.oracle.coherence; import com.oracle.coherence.patterns.pushreplication.EntryOperation; import java.sql.*; import java.text.SimpleDateFormat; import com.oracle.coherence.Order; public class DatabasePersistence { public static String INSERT_OPERATION = "INSERT"; public static String UPDATE_OPERATION = "UPDATE"; public Connection dbConnection; public DatabasePersistence(String jdbcString, String username, String password) { this.dbConnection = createConnection(jdbcString, username, password); } public Connection createConnection(String jdbcString, String username, String password) { Connection connection = null; System.err.println("Connecting to: " + jdbcString + " Username: " + username + " Password: " + password); try { // Load the JDBC driver String driverName = "oracle.jdbc.driver.OracleDriver"; Class.forName(driverName); // Create a connection to the database connection = DriverManager.getConnection(jdbcString, username, password); System.err.println("Connected to:" + jdbcString + " Username: " + username + " Password: " + password); } catch (ClassNotFoundException e) { e.printStackTrace(); } // driver catch (SQLException e) { e.printStackTrace(); } return connection; } public void databasePersist(EntryOperation entryOperation) { if (entryOperation.getOperation().toString() .equalsIgnoreCase(INSERT_OPERATION)) { insert(((Order) entryOperation.getPublishableEntry().getValue())); } else if (entryOperation.getOperation().toString() .equalsIgnoreCase(UPDATE_OPERATION)) { update(((Order) entryOperation.getPublishableEntry().getValue())); } } public void update(Order order) { String update = "UPDATE Orders set QUANTITY= '" + order.getQuantity() + "', AMOUNT='" + order.getAmount() + "', ORD_DATE= '" + (new SimpleDateFormat("dd-MMM-yyyy")).format(order .getOrdDate()) + "' WHERE SYMBOL='" + order.getSymbol() + "'"; System.err.println("UPDATE = " + update); try { Statement stmt = getDbConnection().createStatement(); stmt.execute(update); stmt.close(); } catch (SQLException ex) { System.err.println("SQLException: " + ex.getMessage()); } } public void insert(Order order) { String insert = "insert into Orders values('" + order.getSymbol() + "'," + order.getQuantity() + "," + order.getAmount() + ",'" + (new SimpleDateFormat("dd-MMM-yyyy")).format(order .getOrdDate()) + "')"; System.err.println("INSERT = " + insert); try { Statement stmt = getDbConnection().createStatement(); stmt.execute(insert); stmt.close(); } catch (SQLException ex) { System.err.println("SQLException: " + ex.getMessage()); } } public Connection getDbConnection() { return dbConnection; } public void setDbConnection(Connection dbConnection) { this.dbConnection = dbConnection; } } Step 4: Now we need to register our publisher against a ContentHandler. In order to achieve that we need to create in our eclipse project a new class called CustomPushReplicationNamespaceContentHandler that should extend the com.oracle.coherence.patterns.pushreplication.configuration.PushReplicationNamespaceContentHandler. In the constructor of the new class we define a new handler for our custom publisher. package com.oracle.coherence; import com.oracle.coherence.configuration.Configurator; import com.oracle.coherence.environment.extensible.ConfigurationContext; import com.oracle.coherence.environment.extensible.ConfigurationException; import com.oracle.coherence.environment.extensible.ElementContentHandler; import com.oracle.coherence.patterns.pushreplication.PublisherScheme; import com.oracle.coherence.environment.extensible.QualifiedName; import com.oracle.coherence.patterns.pushreplication.configuration.PushReplicationNamespaceContentHandler; import com.tangosol.run.xml.XmlElement; public class CustomPushReplicationNamespaceContentHandler extends PushReplicationNamespaceContentHandler { public CustomPushReplicationNamespaceContentHandler() { super(); registerContentHandler("custom-publisher-scheme", new ElementContentHandler() { public Object onElement(ConfigurationContext context, QualifiedName qualifiedName, XmlElement xmlElement) throws ConfigurationException { PublisherScheme publisherScheme = new CustomPublisherScheme(); Configurator.configure(publisherScheme, context, qualifiedName, xmlElement); return publisherScheme; } }); } } Step 5: Now we should define our CustomPublisher in the cache configuration file according to the following documentation. <cache-config xmlns:sync="class:com.oracle.coherence.CustomPushReplicationNamespaceContentHandler" xmlns:cr="class:com.oracle.coherence.environment.extensible.namespaces.InstanceNamespaceContentHandler"> <caching-schemes> <sync:provider pof-enabled="false"> <sync:coherence-provider /> </sync:provider> <caching-scheme-mapping> <cache-mapping> <cache-name>publishing-cache</cache-name> <scheme-name>distributed-scheme-with-publishing-cachestore</scheme-name> <autostart>true</autostart> <sync:publisher> <sync:publisher-name>Active2 Publisher</sync:publisher-name> <sync:publisher-scheme> <sync:remote-cluster-publisher-scheme> <sync:remote-invocation-service-name>remote-site1</sync:remote-invocation-service-name> <sync:remote-publisher-scheme> <sync:local-cache-publisher-scheme> <sync:target-cache-name>publishing-cache</sync:target-cache-name> </sync:local-cache-publisher-scheme> </sync:remote-publisher-scheme> <sync:autostart>true</sync:autostart> </sync:remote-cluster-publisher-scheme> </sync:publisher-scheme> </sync:publisher> <sync:publisher> <sync:publisher-name>Active2-Output-Publisher</sync:publisher-name> <sync:publisher-scheme> <sync:stderr-publisher-scheme> <sync:autostart>true</sync:autostart> <sync:publish-original-value>true</sync:publish-original-value> </sync:stderr-publisher-scheme> </sync:publisher-scheme> </sync:publisher> <sync:publisher> <sync:publisher-name>Active2-JDBC-Publisher</sync:publisher-name> <sync:publisher-scheme> <sync:custom-publisher-scheme> <sync:jdbc-string>jdbc:oracle:thin:@machine_name:1521:XE</sync:jdbc-string> <sync:username>hr</sync:username> <sync:password>hr</sync:password> </sync:custom-publisher-scheme> </sync:publisher-scheme> </sync:publisher> </cache-mapping> </caching-scheme-mapping> <!-- The following scheme is required for each remote-site when using a RemoteInvocationPublisher --> <remote-invocation-scheme> <service-name>remote-site1</service-name> <initiator-config> <tcp-initiator> <remote-addresses> <socket-address> <address>localhost</address> <port>20001</port> </socket-address> </remote-addresses> <connect-timeout>2s</connect-timeout> </tcp-initiator> <outgoing-message-handler> <request-timeout>5s</request-timeout> </outgoing-message-handler> </initiator-config> </remote-invocation-scheme> <!-- END: com.oracle.coherence.patterns.pushreplication --> <proxy-scheme> <service-name>ExtendTcpProxyService</service-name> <acceptor-config> <tcp-acceptor> <local-address> <address>localhost</address> <port>20002</port> </local-address> </tcp-acceptor> </acceptor-config> <autostart>true</autostart> </proxy-scheme> </caching-schemes> </cache-config> As you can see in the red-marked text from above I've:       - set new Namespace Content Handler       - define the new custom publisher that should work together with other publishers like: stderr and remote publishers in our case. Step 6: Add the com.oracle.coherence.CustomPublisherScheme to your custom-pof-config file: <pof-config> <user-type-list> <!-- Built in types --> <include>coherence-pof-config.xml</include> <include>coherence-common-pof-config.xml</include> <include>coherence-messagingpattern-pof-config.xml</include> <include>coherence-pushreplicationpattern-pof-config.xml</include> <!-- Application types --> <user-type> <type-id>1901</type-id> <class-name>com.oracle.coherence.Order</class-name> <serializer> <class-name>com.oracle.coherence.OrderSerializer</class-name> </serializer> </user-type> <user-type> <type-id>1902</type-id> <class-name>com.oracle.coherence.CustomPublisherScheme</class-name> </user-type> </user-type-list> </pof-config> CONCLUSIONSThis approach allows for publishers to publish data to almost any other receiver (database, JMS, MQ, ...). The only thing that needs to be changed is the DatabasePersistence.java class that should be adapted to the chosen receiver. Only minor changes are needed for the rest of the code (to publishBatch method from CustomPublisher class).

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• Currency Conversion in Oracle BI applications

  - by Saurabh Verma

  Authored by Vijay Aggarwal and Hichem Sellami A typical data warehouse contains Star and/or Snowflake schema, made up of Dimensions and Facts. The facts store various numerical information including amounts. Example; Order Amount, Invoice Amount etc. With the true global nature of business now-a-days, the end-users want to view the reports in their own currency or in global/common currency as defined by their business. This presents a unique opportunity in BI to provide the amounts in converted rates either by pre-storing or by doing on-the-fly conversions while displaying the reports to the users. Source Systems OBIA caters to various source systems like EBS, PSFT, Sebl, JDE, Fusion etc. Each source has its own unique and intricate ways of defining and storing currency data, doing currency conversions and presenting to the OLTP users. For example; EBS stores conversion rates between currencies which can be classified by conversion rates, like Corporate rate, Spot rate, Period rate etc. Siebel stores exchange rates by conversion rates like Daily. EBS/Fusion stores the conversion rates for each day, where as PSFT/Siebel store for a range of days. PSFT has Rate Multiplication Factor and Rate Division Factor and we need to calculate the Rate based on them, where as other Source systems store the Currency Exchange Rate directly. OBIA Design The data consolidation from various disparate source systems, poses the challenge to conform various currencies, rate types, exchange rates etc., and designing the best way to present the amounts to the users without affecting the performance. When consolidating the data for reporting in OBIA, we have designed the mechanisms in the Common Dimension, to allow users to report based on their required currencies. OBIA Facts store amounts in various currencies: Document Currency: This is the currency of the actual transaction. For a multinational company, this can be in various currencies. Local Currency: This is the base currency in which the accounting entries are recorded by the business. This is generally defined in the Ledger of the company. Global Currencies: OBIA provides five Global Currencies. Three are used across all modules. The last two are for CRM only. A Global currency is very useful when creating reports where the data is viewed enterprise-wide. Example; a US based multinational would want to see the reports in USD. The company will choose USD as one of the global currencies. OBIA allows users to define up-to five global currencies during the initial implementation. The term Currency Preference is used to designate the set of values: Document Currency, Local Currency, Global Currency 1, Global Currency 2, Global Currency 3; which are shared among all modules. There are four more currency preferences, specific to certain modules: Global Currency 4 (aka CRM Currency) and Global Currency 5 which are used in CRM; and Project Currency and Contract Currency, used in Project Analytics. When choosing Local Currency for Currency preference, the data will show in the currency of the Ledger (or Business Unit) in the prompt. So it is important to select one Ledger or Business Unit when viewing data in Local Currency. More on this can be found in the section: Toggling Currency Preferences in the Dashboard. Design Logic When extracting the fact data, the OOTB mappings extract and load the document amount, and the local amount in target tables. It also loads the exchange rates required to convert the document amount into the corresponding global amounts. If the source system only provides the document amount in the transaction, the extract mapping does a lookup to get the Local currency code, and the Local exchange rate. The Load mapping then uses the local currency code and rate to derive the local amount. The load mapping also fetches the Global Currencies and looks up the corresponding exchange rates. The lookup of exchange rates is done via the Exchange Rate Dimension provided as a Common/Conforming Dimension in OBIA. The Exchange Rate Dimension stores the exchange rates between various currencies for a date range and Rate Type. Two physical tables W_EXCH_RATE_G and W_GLOBAL_EXCH_RATE_G are used to provide the lookups and conversions between currencies. The data is loaded from the source system’s Ledger tables. W_EXCH_RATE_G stores the exchange rates between currencies with a date range. On the other hand, W_GLOBAL_EXCH_RATE_G stores the currency conversions between the document currency and the pre-defined five Global Currencies for each day. Based on the requirements, the fact mappings can decide and use one or both tables to do the conversion. Currency design in OBIA also taps into the MLS and Domain architecture, thus allowing the users to map the currencies to a universal Domain during the implementation time. This is especially important for companies deploying and using OBIA with multiple source adapters. Some Gotchas to Look for It is necessary to think through the currencies during the initial implementation. 1) Identify various types of currencies that are used by your business. Understand what will be your Local (or Base) and Documentation currency. Identify various global currencies that your users will want to look at the reports. This will be based on the global nature of your business. Changes to these currencies later in the project, while permitted, but may cause Full data loads and hence lost time. 2) If the user has a multi source system make sure that the Global Currencies and Global Rate Types chosen in Configuration Manager do have the corresponding source specific counterparts. In other words, make sure for every DW specific value chosen for Currency Code or Rate Type, there is a source Domain mapping already done. Technical Section This section will briefly mention the technical scenarios employed in the OBIA adaptors to extract data from each source system. In OBIA, we have two main tables which store the Currency Rate information as explained in previous sections. W_EXCH_RATE_G and W_GLOBAL_EXCH_RATE_G are the two tables. W_EXCH_RATE_G stores all the Currency Conversions present in the source system. It captures data for a Date Range. W_GLOBAL_EXCH_RATE_G has Global Currency Conversions stored at a Daily level. However the challenge here is to store all the 5 Global Currency Exchange Rates in a single record for each From Currency. Let’s voyage further into the Source System Extraction logic for each of these tables and understand the flow briefly. EBS: In EBS, we have Currency Data stored in GL_DAILY_RATES table. As the name indicates GL_DAILY_RATES EBS table has data at a daily level. However in our warehouse we store the data with a Date Range and insert a new range record only when the Exchange Rate changes for a particular From Currency, To Currency and Rate Type. Below are the main logical steps that we employ in this process. (Incremental Flow only) – Cleanup the data in W_EXCH_RATE_G. Delete the records which have Start Date > minimum conversion date Update the End Date of the existing records. Compress the daily data from GL_DAILY_RATES table into Range Records. Incremental map uses $$XRATE_UPD_NUM_DAY as an extra parameter. Generate Previous Rate, Previous Date and Next Date for each of the Daily record from the OLTP. Filter out the records which have Conversion Rate same as Previous Rates or if the Conversion Date lies within a single day range. Mark the records as ‘Keep’ and ‘Filter’ and also get the final End Date for the single Range record (Unique Combination of From Date, To Date, Rate and Conversion Date). Filter the records marked as ‘Filter’ in the INFA map. The above steps will load W_EXCH_RATE_GS. Step 0 updates/deletes W_EXCH_RATE_G directly. SIL map will then insert/update the GS data into W_EXCH_RATE_G. These steps convert the daily records in GL_DAILY_RATES to Range records in W_EXCH_RATE_G. We do not need such special logic for loading W_GLOBAL_EXCH_RATE_G. This is a table where we store data at a Daily Granular Level. However we need to pivot the data because the data present in multiple rows in source tables needs to be stored in different columns of the same row in DW. We use GROUP BY and CASE logic to achieve this. Fusion: Fusion has extraction logic very similar to EBS. The only difference is that the Cleanup logic that was mentioned in step 0 above does not use $$XRATE_UPD_NUM_DAY parameter. In Fusion we bring all the Exchange Rates in Incremental as well and do the cleanup. The SIL then takes care of Insert/Updates accordingly. PeopleSoft:PeopleSoft does not have From Date and To Date explicitly in the Source tables. Let’s look at an example. Please note that this is achieved from PS1 onwards only. 1 Jan 2010 – USD to INR – 45 31 Jan 2010 – USD to INR – 46 PSFT stores records in above fashion. This means that Exchange Rate of 45 for USD to INR is applicable for 1 Jan 2010 to 30 Jan 2010. We need to store data in this fashion in DW. Also PSFT has Exchange Rate stored as RATE_MULT and RATE_DIV. We need to do a RATE_MULT/RATE_DIV to get the correct Exchange Rate. We generate From Date and To Date while extracting data from source and this has certain assumptions: If a record gets updated/inserted in the source, it will be extracted in incremental. Also if this updated/inserted record is between other dates, then we also extract the preceding and succeeding records (based on dates) of this record. This is required because we need to generate a range record and we have 3 records whose ranges have changed. Taking the same example as above, if there is a new record which gets inserted on 15 Jan 2010; the new ranges are 1 Jan to 14 Jan, 15 Jan to 30 Jan and 31 Jan to Next available date. Even though 1 Jan record and 31 Jan have not changed, we will still extract them because the range is affected. Similar logic is used for Global Exchange Rate Extraction. We create the Range records and get it into a Temporary table. Then we join to Day Dimension, create individual records and pivot the data to get the 5 Global Exchange Rates for each From Currency, Date and Rate Type. Siebel: Siebel Facts are dependent on Global Exchange Rates heavily and almost none of them really use individual Exchange Rates. In other words, W_GLOBAL_EXCH_RATE_G is the main table used in Siebel from PS1 release onwards. As of January 2002, the Euro Triangulation method for converting between currencies belonging to EMU members is not needed for present and future currency exchanges. However, the method is still available in Siebel applications, as are the old currencies, so that historical data can be maintained accurately. The following description applies only to historical data needing conversion prior to the 2002 switch to the Euro for the EMU member countries. If a country is a member of the European Monetary Union (EMU), you should convert its currency to other currencies through the Euro. This is called triangulation, and it is used whenever either currency being converted has EMU Triangulation checked. Due to this, there are multiple extraction flows in SEBL ie. EUR to EMU, EUR to NonEMU, EUR to DMC and so on. We load W_EXCH_RATE_G through multiple flows with these data. This has been kept same as previous versions of OBIA. W_GLOBAL_EXCH_RATE_G being a new table does not have such needs. However SEBL does not have From Date and To Date columns in the Source tables similar to PSFT. We use similar extraction logic as explained in PSFT section for SEBL as well. What if all 5 Global Currencies configured are same? As mentioned in previous sections, from PS1 onwards we store Global Exchange Rates in W_GLOBAL_EXCH_RATE_G table. The extraction logic for this table involves Pivoting data from multiple rows into a single row with 5 Global Exchange Rates in 5 columns. As mentioned in previous sections, we use CASE and GROUP BY functions to achieve this. This approach poses a unique problem when all the 5 Global Currencies Chosen are same. For example – If the user configures all 5 Global Currencies as ‘USD’ then the extract logic will not be able to generate a record for From Currency=USD. This is because, not all Source Systems will have a USD->USD conversion record. We have _Generated mappings to take care of this case. We generate a record with Conversion Rate=1 for such cases. Reusable Lookups Before PS1, we had a Mapplet for Currency Conversions. In PS1, we only have reusable Lookups- LKP_W_EXCH_RATE_G and LKP_W_GLOBAL_EXCH_RATE_G. These lookups have another layer of logic so that all the lookup conditions are met when they are used in various Fact Mappings. Any user who would want to do a LKP on W_EXCH_RATE_G or W_GLOBAL_EXCH_RATE_G should and must use these Lookups. A direct join or Lookup on the tables might lead to wrong data being returned. Changing Currency preferences in the Dashboard: In the 796x series, all amount metrics in OBIA were showing the Global1 amount. The customer needed to change the metric definitions to show them in another Currency preference. Project Analytics started supporting currency preferences since 7.9.6 release though, and it published a Tech note for other module customers to add toggling between currency preferences to the solution. List of Currency Preferences Starting from 11.1.1.x release, the BI Platform added a new feature to support multiple currencies. The new session variable (PREFERRED_CURRENCY) is populated through a newly introduced currency prompt. This prompt can take its values from the xml file: userpref_currencies_OBIA.xml, which is hosted in the BI Server installation folder, under :< home>\instances\instance1\config\OracleBIPresentationServicesComponent\coreapplication_obips1\userpref_currencies.xml This file contains the list of currency preferences, like“Local Currency”, “Global Currency 1”,…which customers can also rename to give them more meaningful business names. There are two options for showing the list of currency preferences to the user in the dashboard: Static and Dynamic. In Static mode, all users will see the full list as in the user preference currencies file. In the Dynamic mode, the list shown in the currency prompt drop down is a result of a dynamic query specified in the same file. Customers can build some security into the rpd, so the list of currency preferences will be based on the user roles…BI Applications built a subject area: “Dynamic Currency Preference” to run this query, and give every user only the list of currency preferences required by his application roles. Adding Currency to an Amount Field When the user selects one of the items from the currency prompt, all the amounts in that page will show in the Currency corresponding to that preference. For example, if the user selects “Global Currency1” from the prompt, all data will be showing in Global Currency 1 as specified in the Configuration Manager. If the user select “Local Currency”, all amount fields will show in the Currency of the Business Unit selected in the BU filter of the same page. If there is no particular Business Unit selected in that filter, and the data selected by the query contains amounts in more than one currency (for example one BU has USD as a functional currency, the other has EUR as functional currency), then subtotals will not be available (cannot add USD and EUR amounts in one field), and depending on the set up (see next paragraph), the user may receive an error. There are two ways to add the Currency field to an amount metric: In the form of currency code, like USD, EUR…For this the user needs to add the field “Apps Common Currency Code” to the report. This field is in every subject area, usually under the table “Currency Tag” or “Currency Code”… In the form of currency symbol ($ for USD, € for EUR,…) For this, the user needs to format the amount metrics in the report as a currency column, by specifying the currency tag column in the Column Properties option in Column Actions drop down list. Typically this column should be the “BI Common Currency Code” available in every subject area. Select Column Properties option in the Edit list of a metric. In the Data Format tab, select Custom as Treat Number As. Enter the following syntax under Custom Number Format: [$:currencyTagColumn=Subjectarea.table.column] Where Column is the “BI Common Currency Code” defined to take the currency code value based on the currency preference chosen by the user in the Currency preference prompt.

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• A ToDynamic() Extension Method For Fluent Reflection

  - by Dixin

  Recently I needed to demonstrate some code with reflection, but I felt it inconvenient and tedious. To simplify the reflection coding, I created a ToDynamic() extension method. The source code can be downloaded from here. Problem One example for complex reflection is in LINQ to SQL. The DataContext class has a property Privider, and this Provider has an Execute() method, which executes the query expression and returns the result. Assume this Execute() needs to be invoked to query SQL Server database, then the following code will be expected: using (NorthwindDataContext database = new NorthwindDataContext()) { // Constructs the query. IQueryable<Product> query = database.Products.Where(product => product.ProductID > 0) .OrderBy(product => product.ProductName) .Take(2); // Executes the query. Here reflection is required, // because Provider, Execute(), and ReturnValue are not public members. IEnumerable<Product> results = database.Provider.Execute(query.Expression).ReturnValue; // Processes the results. foreach (Product product in results) { Console.WriteLine("{0}, {1}", product.ProductID, product.ProductName); } } Of course, this code cannot compile. And, no one wants to write code like this. Again, this is just an example of complex reflection. using (NorthwindDataContext database = new NorthwindDataContext()) { // Constructs the query. IQueryable<Product> query = database.Products.Where(product => product.ProductID > 0) .OrderBy(product => product.ProductName) .Take(2); // database.Provider PropertyInfo providerProperty = database.GetType().GetProperty( "Provider", BindingFlags.NonPublic | BindingFlags.GetProperty | BindingFlags.Instance); object provider = providerProperty.GetValue(database, null); // database.Provider.Execute(query.Expression) // Here GetMethod() cannot be directly used, // because Execute() is a explicitly implemented interface method. Assembly assembly = Assembly.Load("System.Data.Linq"); Type providerType = assembly.GetTypes().SingleOrDefault( type => type.FullName == "System.Data.Linq.Provider.IProvider"); InterfaceMapping mapping = provider.GetType().GetInterfaceMap(providerType); MethodInfo executeMethod = mapping.InterfaceMethods.Single(method => method.Name == "Execute"); IExecuteResult executeResult = executeMethod.Invoke(provider, new object[] { query.Expression }) as IExecuteResult; // database.Provider.Execute(query.Expression).ReturnValue IEnumerable<Product> results = executeResult.ReturnValue as IEnumerable<Product>; // Processes the results. foreach (Product product in results) { Console.WriteLine("{0}, {1}", product.ProductID, product.ProductName); } } This may be not straight forward enough. So here a solution will implement fluent reflection with a ToDynamic() extension method: IEnumerable<Product> results = database.ToDynamic() // Starts fluent reflection. .Provider.Execute(query.Expression).ReturnValue; C# 4.0 dynamic In this kind of scenarios, it is easy to have dynamic in mind, which enables developer to write whatever code after a dot: using (NorthwindDataContext database = new NorthwindDataContext()) { // Constructs the query. IQueryable<Product> query = database.Products.Where(product => product.ProductID > 0) .OrderBy(product => product.ProductName) .Take(2); // database.Provider dynamic dynamicDatabase = database; dynamic results = dynamicDatabase.Provider.Execute(query).ReturnValue; } This throws a RuntimeBinderException at runtime: 'System.Data.Linq.DataContext.Provider' is inaccessible due to its protection level. Here dynamic is able find the specified member. So the next thing is just writing some custom code to access the found member. .NET 4.0 DynamicObject, and DynamicWrapper<T> Where to put the custom code for dynamic? The answer is DynamicObject’s derived class. I first heard of DynamicObject from Anders Hejlsberg's video in PDC2008. It is very powerful, providing useful virtual methods to be overridden, like: TryGetMember() TrySetMember() TryInvokeMember() etc.  (In 2008 they are called GetMember, SetMember, etc., with different signature.) For example, if dynamicDatabase is a DynamicObject, then the following code: dynamicDatabase.Provider will invoke dynamicDatabase.TryGetMember() to do the actual work, where custom code can be put into. Now create a type to inherit DynamicObject: public class DynamicWrapper<T> : DynamicObject { private readonly bool _isValueType; private readonly Type _type; private T _value; // Not readonly, for value type scenarios. public DynamicWrapper(ref T value) // Uses ref in case of value type. { if (value == null) { throw new ArgumentNullException("value"); } this._value = value; this._type = value.GetType(); this._isValueType = this._type.IsValueType; } public override bool TryGetMember(GetMemberBinder binder, out object result) { // Searches in current type's public and non-public properties. PropertyInfo property = this._type.GetTypeProperty(binder.Name); if (property != null) { result = property.GetValue(this._value, null).ToDynamic(); return true; } // Searches in explicitly implemented properties for interface. MethodInfo method = this._type.GetInterfaceMethod(string.Concat("get_", binder.Name), null); if (method != null) { result = method.Invoke(this._value, null).ToDynamic(); return true; } // Searches in current type's public and non-public fields. FieldInfo field = this._type.GetTypeField(binder.Name); if (field != null) { result = field.GetValue(this._value).ToDynamic(); return true; } // Searches in base type's public and non-public properties. property = this._type.GetBaseProperty(binder.Name); if (property != null) { result = property.GetValue(this._value, null).ToDynamic(); return true; } // Searches in base type's public and non-public fields. field = this._type.GetBaseField(binder.Name); if (field != null) { result = field.GetValue(this._value).ToDynamic(); return true; } // The specified member is not found. result = null; return false; } // Other overridden methods are not listed. } In the above code, GetTypeProperty(), GetInterfaceMethod(), GetTypeField(), GetBaseProperty(), and GetBaseField() are extension methods for Type class. For example: internal static class TypeExtensions { internal static FieldInfo GetBaseField(this Type type, string name) { Type @base = type.BaseType; if (@base == null) { return null; } return @base.GetTypeField(name) ?? @base.GetBaseField(name); } internal static PropertyInfo GetBaseProperty(this Type type, string name) { Type @base = type.BaseType; if (@base == null) { return null; } return @base.GetTypeProperty(name) ?? @base.GetBaseProperty(name); } internal static MethodInfo GetInterfaceMethod(this Type type, string name, params object[] args) { return type.GetInterfaces().Select(type.GetInterfaceMap).SelectMany(mapping => mapping.TargetMethods) .FirstOrDefault( method => method.Name.Split('.').Last().Equals(name, StringComparison.Ordinal) && method.GetParameters().Count() == args.Length && method.GetParameters().Select( (parameter, index) => parameter.ParameterType.IsAssignableFrom(args[index].GetType())).Aggregate( true, (a, b) => a && b)); } internal static FieldInfo GetTypeField(this Type type, string name) { return type.GetFields( BindingFlags.GetField | BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).FirstOrDefault( field => field.Name.Equals(name, StringComparison.Ordinal)); } internal static PropertyInfo GetTypeProperty(this Type type, string name) { return type.GetProperties( BindingFlags.GetProperty | BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).FirstOrDefault( property => property.Name.Equals(name, StringComparison.Ordinal)); } // Other extension methods are not listed. } So now, when invoked, TryGetMember() searches the specified member and invoke it. The code can be written like this: dynamic dynamicDatabase = new DynamicWrapper<NorthwindDataContext>(ref database); dynamic dynamicReturnValue = dynamicDatabase.Provider.Execute(query.Expression).ReturnValue; This greatly simplified reflection. ToDynamic() and fluent reflection To make it even more straight forward, A ToDynamic() method is provided: public static class DynamicWrapperExtensions { public static dynamic ToDynamic<T>(this T value) { return new DynamicWrapper<T>(ref value); } } and a ToStatic() method is provided to unwrap the value: public class DynamicWrapper<T> : DynamicObject { public T ToStatic() { return this._value; } } In the above TryGetMember() method, please notice it does not output the member’s value, but output a wrapped member value (that is, memberValue.ToDynamic()). This is very important to make the reflection fluent. Now the code becomes: IEnumerable<Product> results = database.ToDynamic() // Here starts fluent reflection. .Provider.Execute(query.Expression).ReturnValue .ToStatic(); // Unwraps to get the static value. With the help of TryConvert(): public class DynamicWrapper<T> : DynamicObject { public override bool TryConvert(ConvertBinder binder, out object result) { result = this._value; return true; } } ToStatic() can be omitted: IEnumerable<Product> results = database.ToDynamic() .Provider.Execute(query.Expression).ReturnValue; // Automatically converts to expected static value. Take a look at the reflection code at the beginning of this post again. Now it is much much simplified! Special scenarios In 90% of the scenarios ToDynamic() is enough. But there are some special scenarios. Access static members Using extension method ToDynamic() for accessing static members does not make sense. Instead, DynamicWrapper<T> has a parameterless constructor to handle these scenarios: public class DynamicWrapper<T> : DynamicObject { public DynamicWrapper() // For static. { this._type = typeof(T); this._isValueType = this._type.IsValueType; } } The reflection code should be like this: dynamic wrapper = new DynamicWrapper<StaticClass>(); int value = wrapper._value; int result = wrapper.PrivateMethod(); So accessing static member is also simple, and fluent of course. Change instances of value types Value type is much more complex. The main problem is, value type is copied when passing to a method as a parameter. This is why ref keyword is used for the constructor. That is, if a value type instance is passed to DynamicWrapper<T>, the instance itself will be stored in this._value of DynamicWrapper<T>. Without the ref keyword, when this._value is changed, the value type instance itself does not change. Consider FieldInfo.SetValue(). In the value type scenarios, invoking FieldInfo.SetValue(this._value, value) does not change this._value, because it changes the copy of this._value. I searched the Web and found a solution for setting the value of field: internal static class FieldInfoExtensions { internal static void SetValue<T>(this FieldInfo field, ref T obj, object value) { if (typeof(T).IsValueType) { field.SetValueDirect(__makeref(obj), value); // For value type. } else { field.SetValue(obj, value); // For reference type. } } } Here __makeref is a undocumented keyword of C#. But method invocation has problem. This is the source code of TryInvokeMember(): public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { if (binder == null) { throw new ArgumentNullException("binder"); } MethodInfo method = this._type.GetTypeMethod(binder.Name, args) ?? this._type.GetInterfaceMethod(binder.Name, args) ?? this._type.GetBaseMethod(binder.Name, args); if (method != null) { // Oops! // If the returnValue is a struct, it is copied to heap. object resultValue = method.Invoke(this._value, args); // And result is a wrapper of that copied struct. result = new DynamicWrapper<object>(ref resultValue); return true; } result = null; return false; } If the returned value is of value type, it will definitely copied, because MethodInfo.Invoke() does return object. If changing the value of the result, the copied struct is changed instead of the original struct. And so is the property and index accessing. They are both actually method invocation. For less confusion, setting property and index are not allowed on struct. Conclusions The DynamicWrapper<T> provides a simplified solution for reflection programming. It works for normal classes (reference types), accessing both instance and static members. In most of the scenarios, just remember to invoke ToDynamic() method, and access whatever you want: StaticType result = someValue.ToDynamic()._field.Method().Property[index]; In some special scenarios which requires changing the value of a struct (value type), this DynamicWrapper<T> does not work perfectly. Only changing struct’s field value is supported. The source code can be downloaded from here, including a few unit test code.

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