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  • Design pattern for isomorphic trees

    - by Peregring-lk
    I want to create a data structure to work with isomorphic tree. I don't search for a "algorithms" or methods to check if two or more trees are isomorphic each other. Just to create various trees with the same structure. Example: 2 - - - - - - - 'a' - - - - - - - 3.5 / \ / \ / \ 3 3 'f' 'y' 1.0 3.1 / \ / \ / \ 4 7 'e' 'f' 2.3 7.7 The first "layer" or tree is the "natural tree" (a tree with natural numbers), the second layer is the "character tree" and the third one is the "float tree". The data structure has a method or iterator to traverse the tree and to make diferent operations with its values. These operations could change the value of nodes, but never its structure (first I create the structure and then I configure the tree with its diferent layers). In case of that I add a new node, this would be applied to each layer. Which known design pattern fits with this description or is related with it?

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  • Email Content creation | Proper design

    - by Umesh Awasthi
    Working on an E commerce application where we need to send so many email to customer like Registration email Forget Password Order placed There are many other emails that can be sent, I already have emailService in place which is responsible for sending email and It needs an Email object, Everything is working find, but I am struck at one point and not sure how best this can be done. We need to create content so as it can be passed to emailService and not sure how to design this. For example, in Customer registration, I have a customerFacade which is working between Controller and ServiceLayer, I just want to delegate this Email Content creation work away from Facade layer and to make it more flexible. Currently I am creating Registration email content inside customerFacade and some how I am not liking this way, since that means for each email, I need to create content in respective Facade. What is best way to go or current approach is fine enough?

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  • How to design application for scaling the application?

    - by Muhammad
    I have one application which handles hardware events connected on the same computer's PCIe slots. The maximum number of PCIe slots on motherboard are two. I have utilized both slots. Now for scaling the application I need either more PCIe slots in same computer or I use another computer. So consider I am using another computer with same application and hardware connected on the PCIe Slots. Now my problem is that I want to design application over it which can access both computers hardware devices and does the process on it. The processed data should be send back to the respective PC's hardware. Please refer the attached diagram for expansion.

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  • Design: How to model / where to store relational data between classes

    - by Walker
    I'm trying to figure out the best design here, and I can see multiple approaches, but none that seems "right." There are three relevant classes here: Base, TradingPost, and Resource. Each Base has a TradingPost which can offer various Resources depending on the Base's tech level. Where is the right place to store the minimum tech level a base must possess to offer any given resource? A database seems like overkill. Putting it in each subclass of Resource seems wrong--that's not an intrinsic property of the Resource. Do I have a mediating class, and if so, how does it work? It's important that I not be duplicating code; that I have one place where I set the required tech level for a given item. Essentially, where does this data belong? P.S. Feel free to change the title; I struggled to come up with one that fits.

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  • How to design console application with good seperation of UI from Logic

    - by JavaSa
    Is it considered an overkill for console application to be design like MVC , MVP or N tier architecture? If not which is more common and if you can link me to simple example of it. I want to implement a tic tac toe game in console application. I have a solution which hold two projects: TicTacToeBusinessLogic (Class library project) and TicTacToeConsoleApplication (Console application project) to represent the view logic. In the TicTacToeConsoleApplication I've Program.cs class which holds the main entry point (public static void Main). Now I face a problem. I want the game to handle its own game flow so I can: Create new GameManager class (from BL) but this causing the view to directly know the BL part. So I'm a little confused how to write it in an acceptable way. Should I use delegates? Please show me a simple example.

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  • Looking for some OO design advice

    - by Andrew Stephens
    I'm developing an app that will be used to open and close valves in an industrial environment, and was thinking of something simple like this:- public static void ValveController { public static void OpenValve(string valveName) { // Implementation to open the valve } public static void CloseValve(string valveName) { // Implementation to close the valve } } (The implementation would write a few bytes of data to the serial port to control the valve - an "address" derived from the valve name, and either a "1" or "0" to open or close the valve). Another dev asked whether we should instead create a separate class for each physical valve, of which there are dozens. I agree it would be nicer to write code like PlasmaValve.Open() rather than ValveController.OpenValve("plasma"), but is this overkill? Also, I was wondering how best to tackle the design with a couple of hypothetical future requirements in mind:- We are asked to support a new type of valve requiring different values to open and close it (not 0 and 1). We are asked to support a valve that can be set to any position from 0-100, rather than simply "open" or "closed". Normally I would use inheritance for this kind of thing, but I've recently started to get my head around "composition over inheritance" and wonder if there is a slicker solution to be had using composition?

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  • How to design a scriptable communication emulator?

    - by Hawk
    Requirement: We need a tool that simulates a hardware device that communicates via RS232 or TCP/IP to allow us to test our main application which will communicate with the device. Current flow: User loads script Parse script into commands User runs script Execute commands Script / commands (simplified for discussion): Connect RS232 = RS232ConnectCommand Connect TCP/IP = TcpIpConnectCommand Send data = SendCommand Receive data = ReceiveCommand Disconnect = DisconnectCommand All commands implement the ICommand interface. The command runner simply executes a sequence of ICommand implementations sequentially thus ICommand must have an Execute exposure, pseudo code: void Execute(ICommunicator context) The Execute method takes a context argument which allows the command implementations to execute what they need to do. For instance SendCommand will call context.Send, etc. The problem RS232ConnectCommand and TcpIpConnectCommand needs to instantiate the context to be used by subsequent commands. How do you handle this elegantly? Solution 1: Change ICommand Execute method to: ICommunicator Execute(ICommunicator context) While it will work it seems like a code smell. All commands now need to return the context which for all commands except the connection ones will be the same context that is passed in. Solution 2: Create an ICommunicatorWrapper (ICommunicationBroker?) which follows the decorator pattern and decorates ICommunicator. It introduces a new exposure: void SetCommunicator(ICommunicator communicator) And ICommand is changed to use the wrapper: void Execute(ICommunicationWrapper context) Seems like a cleaner solution. Question Is this a good design? Am I on the right track?

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  • C# vector class - Interpolation design decision

    - by Benjamin
    Currently I'm working on a vector class in C# and now I'm coming to the point, where I've to figure out, how i want to implement the functions for interpolation between two vectors. At first I came up with implementing the functions directly into the vector class... public class Vector3D { public static Vector3D LinearInterpolate(Vector3D vector1, Vector3D vector2, double factor) { ... } public Vector3D LinearInterpolate(Vector3D other, double factor { ... } } (I always offer both: a static method with two vectors as parameters and one non-static, with only one vector as parameter) ...but then I got the idea to use extension methods (defined in a seperate class called "Interpolation" for example), since interpolation isn't really a thing only available for vectors. So this could be another solution: public class Vector3D { ... } public static class Interpolation { public static Vector3D LinearInterpolate(this Vector3D vector, Vector3D other, double factor) { ... } } So here an example how you'd use the different possibilities: { var vec1 = new Vector3D(5, 3, 1); var vec2 = new Vector3D(4, 2, 0); Vector3D vec3; vec3 = vec1.LinearInterpolate(vec2, 0.5); //1 vec3 = Vector3D.LinearInterpolate(vec1, vec2, 0.5); //2 //or with extension-methods vec3 = vec1.LinearInterpolate(vec2, 0.5); //3 (same as 1) vec3 = Interpolation.LinearInterpolation(vec1, vec2, 0.5); //4 } So I really don't know which design is better. Also I don't know if there's an ultimate rule for things like this or if it's just about what someone personally prefers. But I really would like to hear your opinions, what's better (and if possible why ).

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  • Relative encapsulation design

    - by taher1992
    Let's say I am doing a 2D application with the following design: There is the Level object that manages the world, and there are world objects which are entities inside the Level object. A world object has a location and velocity, as well as size and a texture. However, a world object only exposes get properties. The set properties are private (or protected) and are only available to inherited classes. But of course, Level is responsible for these world objects, and must somehow be able to manipulate at least some of its private setters. But as of now, Level has no access, meaning world objects must change its private setters to public (violating encapsulation). How to tackle this problem? Should I just make everything public? Currently what I'm doing is having a inner class inside game object that does the set work. So when Level needs to update an objects location it goes something like this: void ChangeObject(GameObject targetObject, int newX, int newY){ // targetObject.SetX and targetObject.SetY cannot be set directly var setter = new GameObject.Setter(targetObject); setter.SetX(newX); setter.SetY(newY); } This code feels like overkill, but it doesn't feel right to have everything public so that anything can change an objects location for example.

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  • design for supporting entities with images

    - by brainydexter
    I have multiple entities like Hotels, Destination Cities etc which can contain images. The way I have my system setup right now is, I think of all the images belonging to this universal set (a table in the DB contains filePaths to all the images). When I have to add an image to an entity, I see if the entity exists in this universal set of images. If it exists, attach the reference to this image, else create a new image. E.g.: class ImageEntityHibernateDAO { public void addImageToEntity(IContainImage entity, String filePath, String title, String altText) { ImageEntity image = this.getImage(filePath); if (image == null) image = new ImageEntity(filePath, title, altText); getSession().beginTransaction(); entity.getImages().add(image); getSession().getTransaction().commit(); } } My question is: Earlier I had to write this code for each entity (and each entity would have a Set collection). So, instead of re-writing the same code, I created the following interface: public interface IContainImage { Set<ImageEntity> getImages(); } Entities which have image collections also implements IContainImage interface. Now, for any entity that needs to support adding Image functionality, all I have to invoke from the DAO looks something like this: // in DestinationDAO::addImageToDestination { imageDao.addImageToEntity(destination, imageFileName, imageTitle, imageAltText); // in HotelDAO::addImageToHotel { imageDao.addImageToEntity(hotel, imageFileName, imageTitle, imageAltText); It'd be great help if someone can provide me some critique on this design ? Are there any serious flaws that I'm not seeing right away ?

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  • How to design a scalable notification system?

    - by Trent
    I need to write a notification system manager. Here is my requirements: I need to be able to send a Notification on different platforms, which may be totally different (for exemple, I need to be able to send either an SMS or an E-mail). Sometimes the notification may be the same for all recipients for a given platform, but sometimes it may be a notification per recipients (or several) per platform. Each notification can contain platform specific payload (for exemple an MMS can contains a sound or an image). The system need to be scalable, I need to be able to send a very large amount of notification without crashing either the application or the server. It is a two step process, first a customer may type a message and choose a platform to send to, and the notification(s) should be created to be processed either real-time either later. Then the system needs to send the notification to the platform provider. For now, I end up with some though but I don't know how scalable it will be or if it is a good design. I've though of the following objects (in a pseudo language): a generic Notification object: class Notification { String $message; Payload $payload; Collection<Recipient> $recipients; } The problem with the following objects is what if I've 1.000.000 recipients ? Even if the Recipient object is very small, it'll take too much memory. I could also create one Notification per recipient, but some platform providers requires me to send it in batch, meaning I need to define one Notification with several Recipients. Each created notification could be stored in a persistent storage like a DB or Redis. Would it be a good it to aggregate this later to make sure it is scalable? On the second step, I need to process this notification. But how could I distinguish the notification to the right platform provider? Should I use an object like MMSNotification extending an abstract Notification? or something like Notification.setType('MMS')? To allow to process a lot of notification at the same time, I think a messaging queue system like RabbitMQ may be the right tool. Is it? It would allow me to queue a lot of notification and have several worker to pop notification and process them. But what if I need to batch the recipients as seen above? Then I imagine a NotificationProcessor object for which I could I add NotificationHandler each NotificationHandler would be in charge to connect the platform provider and perform notification. I can also use an EventManager to allow pluggable behavior. Any feedbacks or ideas? Thanks for giving your time. Note: I'm used to work in PHP and it is likely the language of my choice.

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  • Best Design Pattern for Coupling User Interface Components and Data Structures

    - by szahn
    I have a windows desktop application with a tree view. Due to lack of a sound data-binding solution for a tree view, I've implemented my own layer of abstraction on it to bind nodes to my own data structure. The requirements are as follows: Populate a tree view with nodes that resemble fields in a data structure. When a node is clicked, display the appropriate control to modify the value of that property in the instance of the data structure. The tree view is populated with instances of custom TreeNode classes that inherit from TreeNode. The responsibility of each custom TreeNode class is to (1) format the node text to represent the name and value of the associated field in my data structure, (2) return the control used to modify the property value, (3) get the value of the field in the control (3) set the field's value from the control. My custom TreeNode implementation has a property called "Control" which retrieves the proper custom control in the form of the base control. The control instance is stored in the custom node and instantiated upon first retrieval. So each, custom node has an associated custom control which extends a base abstract control class. Example TreeNode implementation: //The Tree Node Base Class public abstract class TreeViewNodeBase : TreeNode { public abstract CustomControlBase Control { get; } public TreeViewNodeBase(ExtractionField field) { UpdateControl(field); } public virtual void UpdateControl(ExtractionField field) { Control.UpdateControl(field); UpdateCaption(FormatValueForCaption()); } public virtual void SaveChanges(ExtractionField field) { Control.SaveChanges(field); UpdateCaption(FormatValueForCaption()); } public virtual string FormatValueForCaption() { return Control.FormatValueForCaption(); } public virtual void UpdateCaption(string newValue) { this.Text = Caption; this.LongText = newValue; } } //The tree node implementation class public class ExtractionTypeNode : TreeViewNodeBase { private CustomDropDownControl control; public override CustomControlBase Control { get { if (control == null) { control = new CustomDropDownControl(); control.label1.Text = Caption; control.comboBox1.Items.Clear(); control.comboBox1.Items.AddRange( Enum.GetNames( typeof(ExtractionField.ExtractionType))); } return control; } } public ExtractionTypeNode(ExtractionField field) : base(field) { } } //The custom control base class public abstract class CustomControlBase : UserControl { public abstract void UpdateControl(ExtractionField field); public abstract void SaveChanges(ExtractionField field); public abstract string FormatValueForCaption(); } //The custom control generic implementation (view) public partial class CustomDropDownControl : CustomControlBase { public CustomDropDownControl() { InitializeComponent(); } public override void UpdateControl(ExtractionField field) { //Nothing to do here } public override void SaveChanges(ExtractionField field) { //Nothing to do here } public override string FormatValueForCaption() { //Nothing to do here return string.Empty; } } //The custom control specific implementation public class FieldExtractionTypeControl : CustomDropDownControl { public override void UpdateControl(ExtractionField field) { comboBox1.SelectedIndex = comboBox1.FindStringExact(field.Extraction.ToString()); } public override void SaveChanges(ExtractionField field) { field.Extraction = (ExtractionField.ExtractionType) Enum.Parse(typeof(ExtractionField.ExtractionType), comboBox1.SelectedItem.ToString()); } public override string FormatValueForCaption() { return string.Empty; } The problem is that I have "generic" controls which inherit from CustomControlBase. These are just "views" with no logic. Then I have specific controls that inherit from the generic controls. I don't have any functions or business logic in the generic controls because the specific controls should govern how data is associated with the data structure. What is the best design pattern for this?

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  • Database design suggestions for a configurable product eshop

    - by solomongaby
    Hello, I am biulding an e-shop that will have configurable products. The configurable parts will need to have different prices and stocks from the main product. What database design would be best in this case? I started with something like this. Features id name Features Options id id_feature value Products id name price Products Features id id_product id_feature value ( save the value from the feature-options for ease in search ) configurable (yes, no) The problem is that now I am stuck on how to save the configurable product features. I was thinking of saving their value as a json. But that will make saving price modification for a certain option difficult. How would you go about this ? Thank you.

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  • How to compile a schema that uses a DataSet (xs:schema)?

    - by Yaron Naveh
    I have created the simplest web service in c#: public void AddData(DataSet ds) The generated schema (Wsdl) looks like this: <s:schema xmlns:s="http://www.w3.org/2001/XMLSchema"> ... <s:element ref="s:schema" /> ... </s:schema> Note the schema does not contain any import/include elements. I am trying to load this schema to a c# System.Xml.XmlSchema and add it to System.Xml.XmlSchemaSet: var set = new XmlSchemaSet(); var fs = new FileStream(@"c:\temp\schema.xsd", FileMode.Open); var s = XmlSchema.Read(fs, null); set.Add(s); set.Compile(); The last line throws this exception: The 'http://www.w3.org/2001/XMLSchema:schema' element is not declared. It kind of makes sense: The schema generated by .Net uses the "s:schema" type which is declared in a schema which is not imported. Why does .Net create a non valid schema? How to compile the schema anyway? Whay I did is download the schema in http://www.w3.org/2001/XMLSchema and added it to the XmlSchemaSet also. This did not work since that online schema contains DTD definition. I had to manually remove it and now all works. Does this make sense or am I missing something?

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  • Is the RESTORE process dependent on schema?

    - by Martin Aatmaa
    Let's say I have two database instances: InstanceA - Production server InstanceB - Test server My workflow is to deploy new schema changes to InstanceB first, test them, and then deploy them to InstanceA. So, at any one time, the instance schema relationship looks like this: InstanceA - Schema Version 1.5 InstanceB - Schema Version 1.6 (new version being tested) An additional part of my workflow is to keep the data in InstanceB as fresh as possible. To fulfill this, I am taking the database backups of InstanceA and applying them (restoring them) to InstanceB. My question is, how does schema version affect the restoral process? I know I can do this: Backup InstanceA - Schema Version 1.5 Restore to InstanceB - Schema Version 1.5 But can I do this? Backup InstanceA - Schema Version 1.5 Restore to InstanceB - Schema Version 1.6 (new version being tested) If no, what would the failure look like? If yes, would the type of schema change matter? For example, if Schema Version 1.6 differed from Schema Version 1.5 by just having an altered storec proc, I imagine that this type of schema change should't affect the restoral process. On the other hand, if Schema Version 1.6 differed from Schema Version 1.5 by having a different table definition (say, an additional column), I image this would affect the restoral process. I hope I've made this clear enough. Thanks in advance for any input!

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  • Oracle Data Mining a Star Schema: Telco Churn Case Study

    - by charlie.berger
    There is a complete and detailed Telco Churn case study "How to" Blog Series just posted by Ari Mozes, ODM Dev. Manager.  In it, Ari provides detailed guidance in how to leverage various strengths of Oracle Data Mining including the ability to: mine Star Schemas and join tables and views together to obtain a complete 360 degree view of a customer combine transactional data e.g. call record detail (CDR) data, etc. define complex data transformation, model build and model deploy analytical methodologies inside the Database  His blog is posted in a multi-part series.  Below are some opening excerpts for the first 3 blog entries.  This is an excellent resource for any novice to skilled data miner who wants to gain competitive advantage by mining their data inside the Oracle Database.  Many thanks Ari! Mining a Star Schema: Telco Churn Case Study (1 of 3) One of the strengths of Oracle Data Mining is the ability to mine star schemas with minimal effort.  Star schemas are commonly used in relational databases, and they often contain rich data with interesting patterns.  While dimension tables may contain interesting demographics, fact tables will often contain user behavior, such as phone usage or purchase patterns.  Both of these aspects - demographics and usage patterns - can provide insight into behavior.Churn is a critical problem in the telecommunications industry, and companies go to great lengths to reduce the churn of their customer base.  One case study1 describes a telecommunications scenario involving understanding, and identification of, churn, where the underlying data is present in a star schema.  That case study is a good example for demonstrating just how natural it is for Oracle Data Mining to analyze a star schema, so it will be used as the basis for this series of posts...... Mining a Star Schema: Telco Churn Case Study (2 of 3) This post will follow the transformation steps as described in the case study, but will use Oracle SQL as the means for preparing data.  Please see the previous post for background material, including links to the case study and to scripts that can be used to replicate the stages in these posts.1) Handling missing values for call data recordsThe CDR_T table records the number of phone minutes used by a customer per month and per call type (tariff).  For example, the table may contain one record corresponding to the number of peak (call type) minutes in January for a specific customer, and another record associated with international calls in March for the same customer.  This table is likely to be fairly dense (most type-month combinations for a given customer will be present) due to the coarse level of aggregation, but there may be some missing values.  Missing entries may occur for a number of reasons: the customer made no calls of a particular type in a particular month, the customer switched providers during the timeframe, or perhaps there is a data entry problem.  In the first situation, the correct interpretation of a missing entry would be to assume that the number of minutes for the type-month combination is zero.  In the other situations, it is not appropriate to assume zero, but rather derive some representative value to replace the missing entries.  The referenced case study takes the latter approach.  The data is segmented by customer and call type, and within a given customer-call type combination, an average number of minutes is computed and used as a replacement value.In SQL, we need to generate additional rows for the missing entries and populate those rows with appropriate values.  To generate the missing rows, Oracle's partition outer join feature is a perfect fit.  select cust_id, cdre.tariff, cdre.month, minsfrom cdr_t cdr partition by (cust_id) right outer join     (select distinct tariff, month from cdr_t) cdre     on (cdr.month = cdre.month and cdr.tariff = cdre.tariff);   ....... Mining a Star Schema: Telco Churn Case Study (3 of 3) Now that the "difficult" work is complete - preparing the data - we can move to building a predictive model to help identify and understand churn.The case study suggests that separate models be built for different customer segments (high, medium, low, and very low value customer groups).  To reduce the data to a single segment, a filter can be applied: create or replace view churn_data_high asselect * from churn_prep where value_band = 'HIGH'; It is simple to take a quick look at the predictive aspects of the data on a univariate basis.  While this does not capture the more complex multi-variate effects as would occur with the full-blown data mining algorithms, it can give a quick feel as to the predictive aspects of the data as well as validate the data preparation steps.  Oracle Data Mining includes a predictive analytics package which enables quick analysis. begin  dbms_predictive_analytics.explain(   'churn_data_high','churn_m6','expl_churn_tab'); end; /select * from expl_churn_tab where rank <= 5 order by rank; ATTRIBUTE_NAME       ATTRIBUTE_SUBNAME EXPLANATORY_VALUE RANK-------------------- ----------------- ----------------- ----------LOS_BAND                                      .069167052          1MINS_PER_TARIFF_MON  PEAK-5                   .034881648          2REV_PER_MON          REV-5                    .034527798          3DROPPED_CALLS                                 .028110322          4MINS_PER_TARIFF_MON  PEAK-4                   .024698149          5From the above results, it is clear that some predictors do contain information to help identify churn (explanatory value > 0).  The strongest uni-variate predictor of churn appears to be the customer's (binned) length of service.  The second strongest churn indicator appears to be the number of peak minutes used in the most recent month.  The subname column contains the interior piece of the DM_NESTED_NUMERICALS column described in the previous post.  By using the object relational approach, many related predictors are included within a single top-level column. .....   NOTE:  These are just EXCERPTS.  Click here to start reading the Oracle Data Mining a Star Schema: Telco Churn Case Study from the beginning.    

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  • Cannot validate xml doc againest a xsd schema (Cannot find the declaration of element 'replyMessage

    - by Daziplqa
    Hi Guyz, I am using the following code to validate an an XML file against a XSD schema package com.forat.xsd; import java.io.IOException; import java.net.URL; import javax.xml.XMLConstants; import javax.xml.transform.Source; import javax.xml.transform.stream.StreamSource; import javax.xml.validation.Schema; import javax.xml.validation.SchemaFactory; import javax.xml.validation.Validator; import org.xml.sax.ErrorHandler; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; public class XSDValidate { public void validate(String xmlFile, String xsd_url) { try { SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI); Schema schema = factory.newSchema(new URL(xsd_url)); Validator validator = schema.newValidator(); ValidationHandler handler = new ValidationHandler(); validator.setErrorHandler(handler); validator.validate(getSource(xmlFile)); if (handler.errorsFound == true) { System.err.println("Validation Error : "+ handler.exception.getMessage()); }else { System.out.println("DONE"); } } catch (SAXException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } private Source getSource(String resource) { return new StreamSource(XSDValidate.class.getClassLoader().getResourceAsStream(resource)); } private class ValidationHandler implements ErrorHandler { private boolean errorsFound = false; private SAXParseException exception; public void error(SAXParseException exception) throws SAXException { this.errorsFound = true; this.exception = exception; } public void fatalError(SAXParseException exception) throws SAXException { this.errorsFound = true; this.exception = exception; } public void warning(SAXParseException exception) throws SAXException { } } /* * Test */ public static void main(String[] args) { new XSDValidate().validate("com/forat/xsd/reply.xml", "https://ics2wstest.ic3.com/commerce/1.x/transactionProcessor/CyberSourceTransaction_1.53.xsd"); // return error } } As appears, It is a standard code that try to validate the following XML file: <?xml version="1.0" encoding="UTF-8"?> <replyMessage xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <merchantReferenceCode>XXXXXXXXXXXXX</merchantReferenceCode> <requestID>XXXXXXXXXXXXX</requestID> <decision>XXXXXXXXXXXXX</decision> <reasonCode>XXXXXXXXXXXXX</reasonCode> <requestToken>XXXXXXXXXXXXX </requestToken> <purchaseTotals> <currency>XXXXXXXXXXXXX</currency> </purchaseTotals> <ccAuthReply> <reasonCode>XXXXXXXXXXXXX</reasonCode> <amount>XXXXXXXXXXXXX</amount> <authorizationCode>XXXXXXXXXXXXX</authorizationCode> <avsCode>XXXXXXXXXXXXX</avsCode> <avsCodeRaw>XXXXXXXXXXXXX</avsCodeRaw> <authorizedDateTime>XXXXXXXXXXXXX</authorizedDateTime> <processorResponse>0XXXXXXXXXXXXX</processorResponse> <authRecord>XXXXXXXXXXXXX </authRecord> </ccAuthReply> </replyMessage> Against the following XSD : https://ics2wstest.ic3.com/commerce/1.x/transactionProcessor/CyberSourceTransaction_1.53.xsd The error is : Validation Error : cvc-elt.1: Cannot find the declaration of element 'replyMessage'. Could you please help me!

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  • Design for a plugin based application

    - by Varun Naik
    I am working on application, details of which I cannot discuss here. We have core framework and the rest is designed as plug in. In the core framework we have a domain object. This domain object is updated by the plugins. I have defined an interface in which I have function as DomainObject doProcessing(DomainObject object) My intention here is I pass the domain object, the plug in will update it and return it. This updated object is then passed again to different plugin to be updated. I am not sure if this is a good approach. I don't like passing the DomainObject to plugin. Is there a better way I can achieve this? Should I just request data from plugin and update the domain object myself?

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  • Class Design and Structure Online Web Store

    - by Phorce
    I hope I have asked this in the right forum. Basically, we're designing an Online Store and I am designing the class structure for ordering a product and want some clarification on what I have so far: So a customer comes, selects their product, chooses the quantity and selects 'Purchase' (I am using the Facade Pattern - So subsystems execute when this action is performed). My class structure: < Order > < Product > <Customer > There is no inheritance, more Association < Order has < Product , < Customer has < Order . Does this structure look ok? I've noticed that I don't handle the "Quantity" separately, I was just going to add this into the "Product" class, but, do you think it should be a class of it's own? Hope someone can help.

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  • design a model for a system of dependent variables

    - by dbaseman
    I'm dealing with a modeling system (financial) that has dozens of variables. Some of the variables are independent, and function as inputs to the system; most of them are calculated from other variables (independent and calculated) in the system. What I'm looking for is a clean, elegant way to: define the function of each dependent variable in the system trigger a re-calculation, whenever a variable changes, of the variables that depend on it A naive way to do this would be to write a single class that implements INotifyPropertyChanged, and uses a massive case statement that lists out all the variable names x1, x2, ... xn on which others depend, and, whenever a variable xi changes, triggers a recalculation of each of that variable's dependencies. I feel that this naive approach is flawed, and that there must be a cleaner way. I started down the path of defining a CalculationManager<TModel> class, which would be used (in a simple example) something like as follows: public class Model : INotifyPropertyChanged { private CalculationManager<Model> _calculationManager = new CalculationManager<Model>(); // each setter triggers a "PropertyChanged" event public double? Height { get; set; } public double? Weight { get; set; } public double? BMI { get; set; } public Model() { _calculationManager.DefineDependency<double?>( forProperty: model => model.BMI, usingCalculation: (height, weight) => weight / Math.Pow(height, 2), withInputs: model => model.Height, model.Weight); } // INotifyPropertyChanged implementation here } I won't reproduce CalculationManager<TModel> here, but the basic idea is that it sets up a dependency map, listens for PropertyChanged events, and updates dependent properties as needed. I still feel that I'm missing something major here, and that this isn't the right approach: the (mis)use of INotifyPropertyChanged seems to me like a code smell the withInputs parameter is defined as params Expression<Func<TModel, T>>[] args, which means that the argument list of usingCalculation is not checked at compile time the argument list (weight, height) is redundantly defined in both usingCalculation and withInputs I am sure that this kind of system of dependent variables must be common in computational mathematics, physics, finance, and other fields. Does someone know of an established set of ideas that deal with what I'm grasping at here? Would this be a suitable application for a functional language like F#? Edit More context: The model currently exists in an Excel spreadsheet, and is being migrated to a C# application. It is run on-demand, and the variables can be modified by the user from the application's UI. Its purpose is to retrieve variables that the business is interested in, given current inputs from the markets, and model parameters set by the business.

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  • Caching factory design

    - by max
    I have a factory class XFactory that creates objects of class X. Instances of X are very large, so the main purpose of the factory is to cache them, as transparently to the client code as possible. Objects of class X are immutable, so the following code seems reasonable: # module xfactory.py import x class XFactory: _registry = {} def get_x(self, arg1, arg2, use_cache = True): if use_cache: hash_id = hash((arg1, arg2)) if hash_id in _registry: return _registry[hash_id] obj = x.X(arg1, arg2) _registry[hash_id] = obj return obj # module x.py class X: # ... Is it a good pattern? (I know it's not the actual Factory Pattern.) Is there anything I should change? Now, I find that sometimes I want to cache X objects to disk. I'll use pickle for that purpose, and store as values in the _registry the filenames of the pickled objects instead of references to the objects. Of course, _registry itself would have to be stored persistently (perhaps in a pickle file of its own, in a text file, in a database, or simply by giving pickle files the filenames that contain hash_id). Except now the validity of the cached object depends not only on the parameters passed to get_x(), but also on the version of the code that created these objects. Strictly speaking, even a memory-cached object could become invalid if someone modifies x.py or any of its dependencies, and reloads it while the program is running. So far I ignored this danger since it seems unlikely for my application. But I certainly cannot ignore it when my objects are cached to persistent storage. What can I do? I suppose I could make the hash_id more robust by calculating hash of a tuple that contains arguments arg1 and arg2, as well as the filename and last modified date for x.py and every module and data file that it (recursively) depends on. To help delete cache files that won't ever be useful again, I'd add to the _registry the unhashed representation of the modified dates for each record. But even this solution isn't 100% safe since theoretically someone might load a module dynamically, and I wouldn't know about it from statically analyzing the source code. If I go all out and assume every file in the project is a dependency, the mechanism will still break if some module grabs data from an external website, etc.). In addition, the frequency of changes in x.py and its dependencies is quite high, leading to heavy cache invalidation. Thus, I figured I might as well give up some safety, and only invalidate the cache only when there is an obvious mismatch. This means that class X would have a class-level cache validation identifier that should be changed whenever the developer believes a change happened that should invalidate the cache. (With multiple developers, a separate invalidation identifier is required for each.) This identifier is hashed along with arg1 and arg2 and becomes part of the hash keys stored in _registry. Since developers may forget to update the validation identifier or not realize that they invalidated existing cache, it would seem better to add another validation mechanism: class X can have a method that returns all the known "traits" of X. For instance, if X is a table, I might add the names of all the columns. The hash calculation will include the traits as well. I can write this code, but I am afraid that I'm missing something important; and I'm also wondering if perhaps there's a framework or package that can do all of this stuff already. Ideally, I'd like to combine in-memory and disk-based caching.

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  • Design for object with optional and modifiable attributtes?

    - by Ikuzen
    I've been using the Builder pattern to create objects with a large number of attributes, where most of them are optional. But up until now, I've defined them as final, as recommended by Joshua Block and other authors, and haven't needed to change their values. I am wondering what should I do though if I need a class with a substantial number of optional but non-final (mutable) attributes? My Builder pattern code looks like this: public class Example { //All possible parameters (optional or not) private final int param1; private final int param2; //Builder class public static class Builder { private final int param1; //Required parameters private int param2 = 0; //Optional parameters - initialized to default //Builder constructor public Builder (int param1) { this.param1 = param1; } //Setter-like methods for optional parameters public Builder param2(int value) { param2 = value; return this; } //build() method public Example build() { return new Example(this); } } //Private constructor private Example(Builder builder) { param1 = builder.param1; param2 = builder.param2; } } Can I just remove the final keyword from the declaration to be able to access the attributes externally (through normal setters, for example)? Or is there a creational pattern that allows optional but non-final attributes that would be better suited in this case?

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  • Learning how to design knowledge and data flow [closed]

    - by max
    In designing software, I spend a lot of time deciding how the knowledge (algorithms / business logic) and data should be allocated between different entities; that is, which object should know what. I am asking for advice about books, articles, presentations, classes, or other resources that would help me learn how to do it better. I code primarily in Python, but my question is not really language-specific; even if some of the insights I learn don't work in Python, that's fine. I'll give a couple examples to clarify what I mean. Example 1 I want to perform some computation. As a user, I will need to provide parameters to do the computation. I can have all those parameters sent to the "main" object, which then uses them to create other objects as needed. Or I can create one "main" object, as well as several additional objects; the additional objects would then be sent to the "main" object as parameters. What factors should I consider to make this choice? Example 2 Let's say I have a few objects of type A that can perform a certain computation. The main computation often involves using an object of type B that performs some interim computation. I can either "teach" A instances what exact parameters to pass to B instances (i.e., make B "dumb"); or I can "teach" B instances to figure out what needs to be done when looking at an A instance (i.e., make B "smart"). What should I think about when I'm making this choice?

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  • High-Level Application Architecture Question

    - by Jesse Bunch
    So I'm really wanting to improve how I architect the software I code. I want to focus on maintainability and clean code. As you might guess, I've been reading a lot of resources on this topic and all it's doing is making it harder for me to settle on an architecture because I can never tell if my design is the one that the more experienced programmer would've chosen. So I have these requirements: I should connect to one vendor and download form submissions from their API. We'll call them the CompanyA. I should then map those submissions to a schema fit for submitting to another vendor for integration with the email service provider. We'll call them the CompanyB. I should then submit those responses to the ESP (CompanyB) and then instruct the ESP to send that submitter an email. So basically, I'm copying data from one web service to another and then performing an action at the latter web service. I've identified a couple high-level services: The service that downloads data from CompanyA. I called this the CompanyAIntegrator. The service that submits the data to CompanyB. I called this CompanyBIntegrator. So my questions are these: Is this a good design? I've tried to separate the concerns and am planning to use the facade pattern to make the integrators interchangeable if the vendors change in the future. Are my naming conventions accurate and meaningful to you (who knows nothing specific of the project)? Now that I have these services, where should I do the work of taking output from the CompanyAIntegrator and getting it in the format for input to the CompanyBIntegrator? Is this OK to be done in main()? Do you have any general pointers on how you'd code something like this? I imagine this scenario is common to us engineers---especially those working in agencies. Thanks for any help you can give. Learning how to architect well is really mind-cluttering.

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  • How bad is it to have two methods with the same name but different signatures in two classes?

    - by Super User
    I have a design problem related to a public interface, the names of methods, and the understanding of my API and code. I have two classes like this: class A: ... function collision(self): .... ... class B: .... function _collision(self, another_object, l, r, t, b): .... The first class has one public method named collision, and the second has one private method called _collision. The two methods differs in argument type and number. As an example let's say that _collision checks if the object is colliding with another object with certain conditions l, r, t, b (collide on the left side, right side, etc) and returns true or false. The public collision method, on the other hand, resolves all the collisions of the object with other objects. The two methods have the same name because I think it's better to avoid overloading the design with different names for methods that do almost the same thing, but in distinct contexts and classes. Is this clear enough to the reader or I should change the method's name?

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