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• Entity System with C++

  - by Dono

  I'm working on a game engine using the Entity System and I have some questions. How I see Entity System : Components : A class with attributs, set and get. Sprite Physicbody SpaceShip ... System : A class with a list of components. (Component logic) EntityManager Renderer Input Camera ... Entity : Just a empty class with a list of components. What I've done : Currently, I've got a program who allow me to do that : // Create a new entity/ Entity* entity = game.createEntity(); // Add some components. entity->addComponent( new TransformableComponent() ) ->setPosition( 15, 50 ) ->setRotation( 90 ) ->addComponent( new PhysicComponent() ) ->setMass( 70 ) ->addComponent( new SpriteComponent() ) ->setTexture( "name.png" ) ->addToSystem( new RendererSystem() ); My questions Did the system stock a list of components or a list of entities ? In the case where I stock a list of entities, I need to get the component of this entities on each frame, that's probably heavy isn't it ? Did the system stock a list of components or a list of entities ? In the case where I stock a list of entities, I need to get the component of this entities on each frame, that's probably heavy isn't it ?

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• Using unordered_multimap as entity and component storage

  - by natebot13

  The Setup I've made a few games (more like animations) using the Object Oriented method with base classes for objects that extend them, and objects that extend those, and found I couldn't wrap my head around expanding that system to larger game ideas. So I did some research and discovered the Entity-Component system of designing games. I really like the idea, and thoroughly understood the usefulness of it after reading Byte54's perfect answer here: Role of systems in entity systems architecture. With that said, I have decided to create my current game idea using the described Entity-Component system. Having basic knowledge of C++, and SFML, I would like to implement the backbone of this entity component system using an unordered_multimap without classes for the entities themselves. Here's the idea: An unordered_mulitmap stores entity IDs as the lookup term, while the value is an inherited Component object. Examlpe: ____________________________ |ID |Component | ---------------------------- |0 |Movable | |0 |Accelable | |0 |Renderable | |1 |Movable | |1 |Renderable | |2 |Renderable | ---------------------------- So, according to this map of objects, the entity with ID 0 has three components: Movable, Accelable, and Renderable. These component objects store the entity specific data, such as the location, the acceleration, and render flags. The entity is simply and ID, with the components attached to that ID describing its attributes. Problem I want to store the component objects within the map, allowing the map have full ownership of the components. The problem I'm having, is I don't quite understand enough about pointers, shared pointers, and references in order to get that set up. How can I go about initializing these components, with their various member variables, within the unordered_multimap? Can the base component class take on the member variables of its child classes, when defining the map as unordered_multimap<int, component>? Requirements I need a system to be able to grab an entity, with all of its' attached components, and access members from the components in order to do the necessary calculations and reassignments for position, velocity, etc. Need a clarification? Post a comment with your concerns and I will gladly edit or comment back! Thanks in advance! natebot13

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• In an Entity/Component system, can component data be implemented as a simple array of key-value pairs? [on hold]

  - by 010110110101

  I'm trying to wrap my head around how to organize components in an Entity Component Systems once everything in the current scene/level is loaded in memory. (I'm a hobbyist BTW) Some people seem to implement the Entity as an object that contains a list of of "Component" objects. Components contain data organized as an array of key-value pairs. Where the value is serialized "somehow". (pseudocode is loosely in C# for brevity) class Entity { Guid _id; List<Component> _components; } class Component { List<ComponentAttributeValue> _attributes; } class ComponentAttributeValue { string AttributeName; object AttributeValue; } Others describe Components as an in-memory "table". An entity acquires the component by having its key placed in a table. The attributes of the component-entity instance are like the columns in a table class Renderable_Component { List<RenderableComponentAttributeValue> _entities; } class RenderableComponentAttributeValue { Guid entityId; matrix4 transformation; // other stuff for rendering // everything is strongly typed } Others describe this actually as a table. (and such tables sound like an EAV database schema BTW) (and the value is serialized "somehow") Render_Component_Table ---------------- Entity Id Attribute Name Attribute Value and when brought into running code: class Entity { Guid _id; Dictionary<string, object> _attributes; } My specific question is: Given various components, (Renderable, Positionable, Explodeable, Hideable, etc) and given that each component has an attribute with a particular name, (TRANSLATION_MATRIX, PARTICLE_EMISSION_VELOCITY, CAN_HIDE, FAVORITE_COLOR, etc) should: an entity contain a list of components where each component, in turn, has their own array of named attributes with values serialized somehow or should components exist as in-memory tables of entity references and associated with each "row" there are "columns" representing the attribute with values that are specific to each entity instance and are strongly typed or all attributes be stored in an entity as a singular array of named attributes with values serialized somehow (could have name collisions) or something else???

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• Entiity System with C++

  - by Dono

  I'm working on a game engine using the Entity System and I have some questions. How i see Entity System : Components : A class with attributs, set and get. Sprite Physicbody SpaceShip ... System : A class with a list of components. (Component logic) EntityManager Renderer Input Camera ... Entity : Just a empty class with a list of components. What i've done : Currently, i've got a program who allow me to do that : // Create a new entity/ Entity* entity = game.createEntity(); // Add some components. entity->addComponent( new TransformableComponent() ) ->setPosition( 15, 50 ) ->setRotation( 90 ) ->addComponent( new PhysicComponent() ) ->setMass( 70 ) ->addComponent( new SpriteComponent() ) ->setTexture( "name.png" ) ->addToSystem( new RendererSystem() ); My questions Did the system stock a list of components or a list of entities ? In the case where I stock a list of entities, I need to get the component of this entities on each frame, that's probably heavy isn't it ? Did the system stock a list of components or a list of entities ? In the case where I stock a list of entities, I need to get the component of this entities on each frame, that's probably heavy isn't it ?

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• Domain model integration using JSON capable DTOs

  - by g-makulik

  I'm a bit confused about architectural choices for the java/web-applications world. The background is I have a system with certain hardware components (that introduce system immanent active behavior) and a configuration database for system meta and HW-components configuration data (these are even usually self contained, since the HW-components persist configuration data anyway). For realization of the configuration/status data exchange protocol with the HW-components we have chosen the Google Protobuf format, which works well for the directly wired communication with these components. Now we want to develop an abstract model (domain model) for those HW-components and I have the feeling that a plain Java class model would fit best for this (c++ implementation seems to have too much implementation/integration overhead with viable language-bridge interfaces). Google Protobuf message definitions could still serve well to describe DTO objects used to interact with a domain model API. But integrating Google Protobuf messages client side for e.g. data binding in the current view doesn't seem to be a good choice. I'm thinking about some extra serialization features, e.g. for JSON based data exchange with the views/controllers. Most lightweight solutions seem to involve a python based presentation layer using JSON based data transfer (I'm at least not sure to be fully informed about this). Is there some lightweight (applicable for a limited ARM Linux platform) framework available, supporting such architecture to realize a web-application?

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• JPanel superclass doesn't add the components of its subclasses..

  - by Acryl

  Well, I use a JFrame that adds two JPanels. Those JPanels are superclasses, because I find it easier to separate different areas of the GUI into different classes. But here's the problem: I add the (superclass) JPanel to the JFrame I set the layout of the superclass JPanel to new BorderLayout(); I add components in the subclasses, like this: JPanel panel = new JPanel(); panel.setLayout(new GridLayout(2,1)); panel.add(new JLabel("Label:"); panel.add(new JTextField(); add(panel, BorderLayout.NORTH); But it doesn't show. What do I do wrong? I've tried it without an additional JPanel in the subclasses, but it doesn't work either. I use jdk 1.6

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• How To Build An Enterprise Application - Introduction

  - by Tuan Nguyen

  An enterprise application is a software which fulfills 4 core quality attributes: Reliability Flexibility Reusability Maintainability Reliability is the ability of a system or component to perform its required functions under stated conditions for a specific period of time. Because there are no ways more than testing to make sure a system is reliability, we can exchange the term reliability with the term testability. Flexibility is the ability of changing a system's core features without violating unrelated features or components. Although flexibility can helps us to achieve interoperability easily but the opposite is not true. For example, a program might run on multiple platforms, contains logic for many scenarios but that wouldn't mean it was flexibility if it forces us rewrite code in all components when we just want to change some aspects of a feature it had. Reusability is the ability of sharing one or more system's components for another system. We should just open a component's reusability in the context in which it is used. For example, we write classes that implement UI logic and deliver them to only classes which implementing UI. Maintainability is the ability of adding or removing features to a system after it was released. Maintainability consists of many factors such as readability, analyzability, extensibility therein extensibility is critical. Maintainability requires us to write code that is longer and complexer than normal but it doesn't mean we introduce unneccessarily complex code. We always try to make our code clear and transparent to everyone. An application enterprise is built on an enterprise design which consists of two parts: low-level design and high-level design. At low-level design, it focuses on building loose-coupled classes or components. Particularly, it recommends: Each class or component undertakes only single responsibility (design based on unit test) Classes or components implement and work through interfaces (design based on contract) Dependency relationship between classes and components could be injected at run-time (design based on dependency) At high-level design, it focuses on architecting system into tiers and layers. Particularly, it recommends: Divide system into subsystems for deployment. Each subsytem is called a tier. Typical, an enterprise application would have 3 tiers as illustrated in the following figure: Arrange classes and components to logical containers called layers. Typical, an enterprise application would have 5 layers as illustrated in the following figure

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• Are these components compatible and are there any significant bottlenecks?

  - by Tom Gullen

  I'm trying to buy a new pc, for software dev and a bit of gaming. I already have a 500gb HDD , and a PCI sound card I want to use as well. Is all this stuff compatible, and will it all work together and are there any significant bottlenecks? Case, Mobo and PSU "Primo Motion" AMD 880G DDR3 Ready Barebones (Socket AM3) http://www.overclockers.co.uk/showproduct.php?prodid=FS-268-OK&groupid=43&catid=1817&subcat= SSD 64GB Crucial RealSSD C300 64GB 2.5" SATA 6Gb/s Solid State Hard Drive http://www.overclockers.co.uk/showproduct.php?prodid=HD-007-CR&groupid=1657&catid=1660&subcat=1668 CPU AMD Phenom II X6 Six Core 1090T Black Edition 3.20GHz (Socket AM3) http://www.overclockers.co.uk/showproduct.php?prodid=CP-266-AM&groupid=701&catid=6&subcat=1944 RAM 8GB Corsair Vengeance 8GB (2x4GB) DDR3 PC3-15000C9 1866MHz Dual Channel Kit http://www.overclockers.co.uk/showproduct.php?prodid=MY-292-CS&groupid=701&catid=8&subcat=1387 Graphics XFX ATI Radeon HD 5770 1024MB GDDR5 PCI-Express Graphics Card http://www.overclockers.co.uk/showproduct.php?prodid=GX-149-XF

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• How does an OS communicate with other hardware components?

  - by Jack

  How can a program running on a CPU (mostly OS) access other PC hardware? Such as Graphic card, HDD and so? From what I read, in DOS, this was done using BIOS calls, specifically the INT instruction. But, the INT instruction should only jump to the certain space in RAM. So how can some program stored in RAM access other computer hardware, when the CPU can only access RAM, and receive interrupts? Does Windows use INT instructions as well, or is there a new way to communicate with the hardware?

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• Which PC components make the biggest impact on your compile times for Visual Studio?

  - by Rob Allen

  Which PC specifications have the biggest impact on your compile times? Disk? Clock speed? Number of CPU cores?

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• Important hardware components to avoid bottlenecks/improve speed on a laptop?

  - by joelhaus

  Looking for a powerful general use (including web development) laptop running Windows. Price points seem to be all over the place. Many less powerful machines are priced much higher than machines with better specs. How does one navigate this market? Are there any unpublished/under-publicized specs/bottlenecks you look for? Understanding that hardware improves over time, is there an efficient ratio that can be used (or something similar, like Windows Experience Index?) which will indicate how powerful a system is? Thanks in advance! P.S. Here is an example from a laptop released on September 17, 2010. Can anyone pick apart these specs? Is there missing information you would be looking for? OS: Win 7 Display: 16.4" LED backlit Processor: Intel Core i7-740QM, 6MB L3 Cache RAM: 6GB DDR3 1333MHz (8GB max.) Graphics: NVIDIA GeForce GT 425M (1 GB of dedicated DDR3) HDD: 500GB 7200RPM SATA Hard Drive Removable Disc: Blue-ray with DVD±R/RW Misc: webcam/mic/speakers/bluetooth (via Sony Vaio VPC-F137FX/B)

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• What are the components required to run taskpads on a workstation?

  - by Darktux

  we are planning to implement task pads in our enviroment for delegation for user administration.I have few questions regarding this. 1.) To run a taskpad (with AD users and computers) ; does the workstation contain whole set of Administrative tools oris there a way just to compy dsa.msc to all workstations and get done with? Note: All tak pads will be shared on a file share and users access them via powershell scripts. 2.) We are creating MMC's in Windows 7 and keeeping them in a share; will the work with Windows XP too or do we need to develop 2 versions of them? We are aiming to keep away software from workstations and maintain it as much as possible on centralized file shares. Please shoot me any questions or clarifications pertaining to my query.

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• Can XNA Content Pipeline split one content file into several .xnb?

  - by Zeta Two

  Let's say I have an xml file which looks like this <Weapons> <Weapon> <Name>Pistol</Name> ... </Weapon> <Weapon> <Name>MachineGun</Name> ... </Weapon> </Weapons> Would it be possible to use a custom importer/writer/reader to create two files, Pistol.xnb and MachineGun.xnb which I can load individually with Content.Load()? While writing this I realized I could just import a Weapon[] list and split them up with a helper, but I'm still wondering if this is possible?

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• What components should I upgrade to squeeze more life of my pc? [on hold]

  - by Jared

  Hi my current specs are CPU: Intel Core i5 750 2.66 GHz, Socket 1156 Motherboard: Asus P7P55 LX Motherboard, Socket 1156, 4xDIMM DDR3, 2xPCIe-16, 3xPCI, 2xPCIe-1, 14xUSB2, Audio, 1xATA, 6xSATA, RAID, ATX HDD: Seagate Barracuda 7200.11 ST31500341AS Hard Disk Drive, 1500GB, 7200rpm, 32MB Cache, SATA-2 RAM: G.Skill Ripjaw F3-12800CL8D-4GBRM, 2x2GB, DDR3-1600, PC3-12800, CL8, DIMM Video: MSI Radeon 5850 R5850-PM2D1G Video Card, 1024MB, DDR5, PCIe-16, DVI, CrossFire, HDMI PSU: Vantec ION2, 620W ATX PSU, SLI Ready, Black Firstly I know it badly needs an SSD, for which I'm thinking of the Samsung 250gb 840 EVO series. The ram could do with another 4GB, for which I am thinking of replacing the 2x2GB for 2x4GB of the same type. My video card is struggling with the latest releases, so vitally should I ditch the video card and go for something newer (ATI 7850, GTX 660?) or try and get another 5850 for crossfire support? Bearing in mind 5850's are sort of hard to come buy now as they are not stocked in shops usually, which means they have to be bought second hand.

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• Microsoft JScript runtime error: Sys.InvalidOperationException: Two components with the same id.

  - by Irwin

  I'm working in ASP .NET dynamic data. In one of my edit controls I wanted to allow the user to add records from a related table to the current page. (Literally, if you are on the orders page, you would be allowed to add a new customer to the system on this page as well, and then associate it with that order). So, I have a DetailsView set to InsertMode, nested inside of an UpdatePanel, which is shown by a ModalPopupExtender which is invoked when 'add new' is clicked. This doohickey works the first time i execute this process, that is, a customer is added (and i update the dropdown list as well). However, I realized it didn't work (properly) again until I refreshed the entire page. When I attached my debugger, my worst fears were realized (ok, not really). But an exception was being thrown: "Microsoft JScript runtime error: Sys.InvalidOperationException: Two components with the same id." Which seemed to be complaining about a Calendar Extender Control that is part of the details view. Any guidance on what's going on here would be great. Thanks.

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• Why does Cut/Paste of form components sometimes stop working in Delphi 2007 IDE?

  - by robsoft

  This is driving me crazy. I'm not going to take it anymore. I'm going to ask, even at the risk of eternal public humiliation! (If it's something really obvious or that I've done to the system myself). For reasons I've never quite had the patience to work out, every so often the form I'm working on in Delphi 2007's visual form editor goes 'pseudo-read-only'; I can add new components to the form, I can move/resize existing ones (and change any properties in the Object Inspector), and I can select a component and 'copy' it to the clipboard. But I'm completely unable to cut a component from the form, or paste a new copy down. I don't believe it's to do with the 'Lock Controls' Edit menu option as I can toggle this on or off and it has the effect it's supposed to - this disappearance of Cut & Paste happens on the right-click context menu, from the keyboard and from the main Edit menu - it's as if the form has become read only to thing to do with the clipboard. If I close the form in the IDE and then reopen it, everything starts working fine again (just as D1, D3, D5 and D7 always did for me, previously). I'm not going mad, as I'm sure I read something about why this happens on a newsgroup once and it's caught me out from time to time many many times in the last few months, but I've failed to find the newsgroup reference this evening and I've decided that, as more and more Delphi users seem to be making use of StackOverflow, it was worth asking here. Help - when I'm doing lots of form-work it drives me absolutely mad!

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• Perl: remove relative path components but leave symlinks alone?

  - by jnylen

  I need to get Perl to remove relative path components from a Linux path. I've found a couple of functions that almost do what I want, but: File::Spec->rel2abs does too little. It does not resolve ".." into a directory properly. Cwd::realpath does too much. It resolves all symbolic links in the path, which I do not want. Perhaps the best way to illustrate how I want this function to behave is to post a bash log where FixPath is a hypothetical command that gives the desired output: '/tmp/test'$ mkdir -p a/b/c1 a/b/c2 '/tmp/test'$ cd a '/tmp/test/a'$ ln -s b link '/tmp/test/a'$ ls b link '/tmp/test/a'$ cd b '/tmp/test/a/b'$ ls c1 c2 '/tmp/test/a/b'$ FixPath . # rel2abs works here ===> /tmp/test/a/b '/tmp/test/a/b'$ FixPath .. # realpath works here ===> /tmp/test/a '/tmp/test/a/b'$ FixPath c1 # rel2abs works here ===> /tmp/test/a/b/c1 '/tmp/test/a/b'$ FixPath ../b # realpath works here ===> /tmp/test/a/b '/tmp/test/a/b'$ FixPath ../link/c1 # neither one works here ===> /tmp/test/a/link/c1 '/tmp/test/a/b'$ FixPath missing # should work for nonexistent files ===> /tmp/test/a/b/missing

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• How can I remove relative path components but leave symlinks alone in Perl?

  - by jnylen

  I need to get Perl to remove relative path components from a Linux path. I've found a couple of functions that almost do what I want, but: File::Spec->rel2abs does too little. It does not resolve ".." into a directory properly. Cwd::realpath does too much. It resolves all symbolic links in the path, which I do not want. Perhaps the best way to illustrate how I want this function to behave is to post a bash log where FixPath is a hypothetical command that gives the desired output: '/tmp/test'$ mkdir -p a/b/c1 a/b/c2 '/tmp/test'$ cd a '/tmp/test/a'$ ln -s b link '/tmp/test/a'$ ls b link '/tmp/test/a'$ cd b '/tmp/test/a/b'$ ls c1 c2 '/tmp/test/a/b'$ FixPath . # rel2abs works here ===> /tmp/test/a/b '/tmp/test/a/b'$ FixPath .. # realpath works here ===> /tmp/test/a '/tmp/test/a/b'$ FixPath c1 # rel2abs works here ===> /tmp/test/a/b/c1 '/tmp/test/a/b'$ FixPath ../b # realpath works here ===> /tmp/test/a/b '/tmp/test/a/b'$ FixPath ../link/c1 # neither one works here ===> /tmp/test/a/link/c1 '/tmp/test/a/b'$ FixPath missing # should work for nonexistent files ===> /tmp/test/a/b/missing

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• Wicket: Where to add components? Constructor? Or onBeforeRender?

  - by gmallett

  I'm a Wicket newb. This may just be my ignorance of the Wicket lifecycle so please enlighten me! My understanding is that Wicket WebPage objects are instantiated once and then serialized. This has led to a point of confusion for me, see below. Currently I have a template class which I intend to subclass. I followed the example in the Wicket docs demonstrating how to override the template's behavior in the subclass: protected void onBeforeRender() { add(new Label("title", getTitle())); super.onBeforeRender(); } protected String getTitle() { return "template"; } Subclass: protected String getTitle() { return "Home"; } This works very well. What's not clear to me are the "best practices" for this. It seems like onBeforeRender() is called on every request for the page, no? This seems like there would be substantially more processing done on a page if everything is in onBeforeRender(). I could easily follow the example of the other Wicket examples and add some components in the constructor that I do not want to override, but then I've divided by component logic into two places, something I'm hesitant to do. If I add a component that I intend to be in all subclasses, should I add it to the constructor or onBeforeRender()?

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• How important is it that models be consistent across project components?

  - by RonLugge

  I have a project with two components, a server-side component and a client-side component. For various reasons, the client-side device doesn't carry a fully copy of the database around. How important is it that my models have a 1:1 correlation between the two sides? And, to extend the question to my bigger concern, are there any time-bombs I'm going to run into down the line if they don't? I'm not talking about having different information on each side, but rather the way the information is encapsulated will vary. (Obviously, storage mechanisms will also vary) The server side will store each user, each review, each 'item' with seperate tables, and create links between them to gather data as necessary. The client side shouldn't have a complete user database, however, so rather than link against the user for gathering things like 'name', I'd store that on the review. In other words... --- Server Side --- Item: +id //Store stuff about the item User: +id +Name -Password Review: +id +itemId +rating +text +userId --- Device Side --- Item: +id +AverageRating Review: +id +rating +text +userId +name User: +id +Name //Stuff The basic idea is that certain 'critical' information gets moved one level 'up'. A user gets the list of 'items' relevant to their query, with certain review-orientation moved up (i. e. average rating). If they want more info, they query the detail view for the item, and the actual reviews get queried and added to the dataset (and displayed). If they query the actual review, the review gets queried and they pick up some additional user info along the way (maybe; I'm not sure if the user would have any use for any of the additional user information). My basic concern is that I don't wan't to glut the user's bandwidth or local storage with a huge variety of information that they just don't need, even if proper database normalizations suggests that information REALLY should be stored at a 'lower' level. I've phrased this as a fairly low-level conceptual issue because that's the level I'm trying to think / worry over, but if it matters I'm creating a PHP / MySQL server that provides data for a iOS / CoreData client.

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• The Interaction between Three-Tier Client/Server Model and Three-Tier Application Architecture Model

  The three-tier client/server model is a network architectural approach currently used in modern networking. This approach divides a network in to three distinct components. Three-Tier Client/Server Model Components Client Component Server Component Database Component The Client Component of the network typically represents any device on the network. A basic example of this would be computer or another network/web enabled devices that are connected to a network. Network clients request resources on the network, and are usually equipped with a user interface for the presentation of the data returned from the Server Component. This process is done through the use of various software clients, and example of this can be seen through the use of a web browser client. The web browser request information from the Server Component located on the network and then renders the results for the user to process. The Server Components of the network return data based on specific client request back to the requesting client.  Server Components also inherit the attributes of a Client Component in that they are a device on the network and that they can also request information from other Server Components. However what differentiates a Client Component from a Server Component is that a Server Component response to requests from devices on the network. An example of a Server Component can be seen in a web server. A web server listens for new requests and then interprets the request, processes the web pages, and then returns the processed data back to the web browser client so that it may render the data for the user to interpret. The Database Component of the network returns unprocessed data from databases or other resources. This component also inherits attributes from the Server Component in that it is a device on a network, it can request information from other server components and database components, and it also listens for new requests so that it can return data when needed. The three-tier client/server model is very similar to the three-tier application architecture model, and in fact the layers can be mapped to one another. Three-Tier Application Architecture Model Presentation Layer/Logic Business Layer/Logic Data Layer/Logic The Presentation Layer including its underlying logic is very similar to the Client Component of the three-tiered model. The Presentation Layer focuses on interpreting the data returned by the Business Layer as well as presents the data back to the user.  Both the Presentation Layer and the Client Component focus primarily on the user and their experience. This allows for segments of the Business Layer to be distributable and interchangeable because the Presentation Layer is not directly integrated in with Business Layer. The Presentation Layer does not care where the data comes from as long as it is in the proper format. This allows for the Presentation Layer and Business Layer to be stored on one or more different servers so that it can provide a higher availability to clients requesting data. A good example of this is a web site that uses load balancing. When a web site decides to take on the task of load balancing they must obtain a network device that sits in front of a one or machines in order to distribute the request across multiple servers. When a user comes in through the load balanced device they are redirected to a specific server based on a few factors. Common Load Balancing Factors Current Server Availability Current Server Response Time Current Server Priority The Business Layer and corresponding logic are business rules applied to data prior to it being sent to the Presentation Layer. These rules are used to manipulate the data coming from the Data Access Layer, in addition to validating any data prior to being stored in the Data Access Layer. A good example of this would be when a user is trying to create multiple accounts under one email address. The Business Layer logic can prevent duplicate accounts by enforcing a unique email for every new account before the data is even stored in the Data Access Layer. The Server Component can be directly tied to this layer in that the server typically stores and process the Business Layer before it is returned to the end-user via the Presentation Layer. In addition the Server Component can also run automated process through the Business Layer on the data in the Data Access Layer so that additional business analysis can be derived from the data that has been already collected. The Data Layer and its logic are responsible for storing information so that it can be easily retrieved. Typical in most modern applications data is stored in a database management system however data can also be in the form of files stored on a file server. In addition a database can take on one of several forms. Common Database Formats XML File Pipe Delimited File Tab Delimited File Comma Delimited File (CSV) Plain Text File Microsoft Access Microsoft SQL Server MySql Oracle Sybase The Database component of the Networking model can be directly tied to the Data Layer because this is where the Data Layer obtains the data to return back the Business Layer. The Database Component basically allows for a place on the network to store data for future use. This enables applications to save data when they can and then quickly recall the saved data as needed so that the application does not have to worry about storing the data in memory. This prevents overhead that could be created when an application must retain all data in memory. As you can see the Three-Tier Client/Server Networking Model and the Three-Tiered Application Architecture Model rely very heavily on one another to function especially if different aspects of an application are distributed across an entire network. The use of various servers and database servers are wonderful when an application has a need to distribute work across the network. Network Components and Application Layers Interaction Database components will store all data needed for the Data Access Layer to manipulate and return to the Business Layer Server Component executes the Business Layer that manipulates data so that it can be returned to the Presentation Layer Client Component hosts the Presentation Layer that  interprets the data and present it to the user

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• Grid Layouts in ADF Faces using Trinidad

  - by frank.nimphius

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} ADF Faces does provide a data table component but none to define grid layouts. Grids are common in web design and developers often try HTML table markup wrapped in an f:verbatim tag or directly added the page to build a desired layout. Usually these attempts fail, showing unpredictable results, However, ADF Faces does not provide a table layout component, but Apache MyFaces Trinidad does. The Trinidad trh:tableLayout component is a thin wrapper around the HTML table element and contains a series of row layout elements, trh:rowLayout. Each trh:rowLayout component may contain one or many trh:cellLayout components to format cells content. <trh:tableLayout id="tl1" halign="left">   <trh:rowLayout id="rl1" valign="top" halign="left">     <trh:cellFormat id="cf1" width="100" header="true">        <af:outputLabel value="Label 1" id="ol1"/>     </trh:cellFormat>     <trh:cellFormat id="cf2" header="true"                               width="300">        <af:outputLabel value="Label 2" id="outputLabel1"/>        </trh:cellFormat>      </trh:rowLayout>      <trh:rowLayout id="rowLayout1" valign="top" halign="left">        <trh:cellFormat id="cellFormat1" width="100" header="false">           <af:outputLabel value="Label 3" id="outputLabel2"/>        </trh:cellFormat>     </trh:rowLayout>        ... </trh:tableLayout> To add the Trinidad tag library to your ADF Faces projects ... Open the Component Palette and right mouse click into it Choose "Edit Tag Libraries" and select the Trinidad components. Move them to the "Selected Libraries" section and Ok the dialog.The first time you drag a Trinidad component to a page, the web.xml file is updated with the required filters Note: The Trinidad tags don't participate in the ADF Faces RC geometry management. However, they are JSF components that are part of the JSF request lifecycle. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} ADF Faces RC components work well with Trinidad layout components that don't use PPR. The PPR implementation of Trinidad is different from the one in ADF Faces. However, when you mix ADF Faces components with Trinidad components, avoid Trinidad components that have integrated PPR behavior. Only use passive Trinidad components.See:http://myfaces.apache.org/trinidad/trinidad-api/tagdoc/trh_tableLayout.htmlhttp://myfaces.apache.org/trinidad/trinidad-api/tagdoc/trh_rowLayout.htmlhttp://myfaces.apache.org/trinidad/trinidad-api/tagdoc/trh_cellFormat.html .

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• MVC pattern implementation. What is the n-relation between its components

  - by Srodriguez

  Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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• MVC pattern implementation. What is the n-relation between its components

  - by Srodriguez

  Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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• Permission denied install Joomla CiviCRM

  - by Tim

  Dear All, I am trying to install CiviCRM on a Joomla 1.5.17 web server running Ubuntu 9.10. Uploading the package to the tmp directory in /var/www/[site name]/tmp and installing creates this error: Warning: fopen(/var/www/trbcp/administrator/components/com_civicrm/civicrm/templates/CRM/common/civicrm.settings.php.tpl) [function.fopen]: failed to open stream: Permission denied in /var/www/trbcp/libraries/joomla/filesystem/file.php on line 240 Warning: fopen(/var/www/trbcp/administrator/components/com_civicrm/civicrm/templates/CRM/common/civicrm.settings.php.tpl) [function.fopen]: failed to open stream: Permission denied in /var/www/trbcp/libraries/joomla/filesystem/file.php on line 240 Warning: include_once(/var/www/trbcp/administrator/components/com_civicrm/civicrm.settings.php) [function.include-once]: failed to open stream: Permission denied in /var/www/trbcp/administrator/components/com_civicrm/configure.php on line 115 Warning: include_once() [function.include]: Failed opening '/var/www/trbcp/administrator/components/com_civicrm/civicrm.settings.php' for inclusion (include_path='.') in /var/www/trbcp/administrator/components/com_civicrm/configure.php on line 115 Warning: require_once(DB.php) [function.require-once]: failed to open stream: No such file or directory in /var/www/trbcp/administrator/components/com_civicrm/configure.php on line 140 Fatal error: require_once() [function.require]: Failed opening required 'DB.php' (include_path='.') in /var/www/trbcp/administrator/components/com_civicrm/configure.php on line 140 Initially I got a permissions denied error and thought that Joomla did not have permissions to all its directories but looking at Help-System information all the necessary directories are writable. I then decided to chmod 777 all the directories and try again but it still fails. Looking at the directories afterwards it seems that the new directories being created are not being created 777. By changing them I can get at least one step further before the error appears again. My question is does anyone know how to get round this? I am thinking that the new directories being created will require sudo privileges to have mv and create actions carried out, hence the permission denied errors. Can this be configured in Joomla? Or is there a way to specify that new directories created in /var/www/[site name] take 777 by default? any help greatly appreciated! EDIT: P.S. if anyone could give me a clue as to how the insert code feature works as well that would be great! Might make this post a bit more readable! EDIT2: Well I have had a bash at changing the permissions and ownership. sudo chown -R www-data:www-data /var/www/trbcp I then tried changing the whole /var directory (insecure I know but this is a test and dev server for me to find my feet on) to 777 and still getting permission errors. It seems to be error opening stream? Not a php guy so not sure what that is but could it be that permissions to run php script need to change? any thoughts greatly appreciated.

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