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  • Java: initialization problem with private-final-int-value and empty constructor

    - by HH
    $ javac InitInt.java InitInt.java:7: variable right might not have been initialized InitInt(){} ^ 1 error $ cat InitInt.java import java.util.*; import java.io.*; public class InitInt { private final int right; InitInt(){} public static void main(String[] args) { // I don't want to assign any value. // just initialize it, how? InitInt test = new InitInt(); System.out.println(test.getRight()); // later assiging a value } public int getRight(){return right;} } Initialization problem with Constructor InitInt{ // Still the error, "may not be initialized" // How to initialise it? if(snippetBuilder.length()>(charwisePos+25)){ right=charwisePos+25; }else{ right=snippetBuilder.length()-1; } }

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  • Business Layer Pattern on Rails? MVCL

    - by Fabiano PS
    That is a broad question, and I appreciate no short/dumb asnwers like: "Oh that is the model job, this quest is retarded (period)" PROBLEM Where I work at people created a system over 2 years for managing the manufacture process over demand in the most simplified still broad as possible, involving selling, buying, assemble, The system is coded over Ruby On Rails. The result has been changed lots of times and the result is a mess on callbacks (some are called several times), 200+ models, and fat controllers: Total bad. The QUESTION is, if there is a gem, or pattern designed to handle Rails large app logic? The logic whould be able to fully talk to models (whose only concern would be data format handling and validation) What I EXPECT is to reduce complexity from various controllers, and hard to track callbacks into files with the responsibility to handle a business operation logic. In some cases there is the need to wait for a response, in others, only validation of the input is enough and a bg process would take place. ie: -- Sell some products (need to wait the operation to finish) 1. Set a View able to get the products input 2. Controller gets the product list inputed by employee and call the logic Logic::ExecuteWithResponse('sell', 'products', :prods => @product_list_with_qtt, :when => @date, :employee => current_user() ) This Logic would handle buying order, assemble order, machine schedule, warehouse reservation, and others

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  • recursive delete trigger and ON DELETE CASCADE contraints are not deleting everything

    - by bitbonk
    I have a very simple datamodel that represents a tree structure: The RootEntity is the root of such a tree, it can contain children of type ContainerEntity and of type AtomEntity. The type ContainerEntity again can contain children of type ContainerEntity and of type AtomEntity but can not contain children of type RootEntity. Children are referenced in a well known order. The DB model for this is below. My problem now is that when I delete a RootEntity I want all children to be deleted recursively. I have create foreign key with CASCADE DELETE and two delete triggers for this. But it is not deleting everything, it always leaves some items in the ContainerEntity, AtomEntity, ContainerEntity_Children and AtomEntity_Children tables. Seemling beginning with the recursionlevel of 3. CREATE TABLE RootEntity ( Id UNIQUEIDENTIFIER NOT NULL, Name VARCHAR(500) NOT NULL, CONSTRAINT PK_RootEntity PRIMARY KEY NONCLUSTERED (Id), ); CREATE TABLE ContainerEntity ( Id UNIQUEIDENTIFIER NOT NULL, Name VARCHAR(500) NOT NULL, CONSTRAINT PK_ContainerEntity PRIMARY KEY NONCLUSTERED (Id), ); CREATE TABLE AtomEntity ( Id UNIQUEIDENTIFIER NOT NULL, Name VARCHAR(500) NOT NULL, CONSTRAINT PK_AtomEntity PRIMARY KEY NONCLUSTERED (Id), ); CREATE TABLE RootEntity_Children ( ParentId UNIQUEIDENTIFIER NOT NULL, OrderIndex INT NOT NULL, ChildContainerEntityId UNIQUEIDENTIFIER NULL, ChildAtomEntityId UNIQUEIDENTIFIER NULL, ChildIsContainerEntity BIT NOT NULL, CONSTRAINT PK_RootEntity_Children PRIMARY KEY NONCLUSTERED (ParentId, OrderIndex), -- foreign key to parent RootEntity CONSTRAINT FK_RootEntiry_Children__RootEntity FOREIGN KEY (ParentId) REFERENCES RootEntity (Id) ON DELETE CASCADE, -- foreign key to referenced (child) ContainerEntity CONSTRAINT FK_RootEntiry_Children__ContainerEntity FOREIGN KEY (ChildContainerEntityId) REFERENCES ContainerEntity (Id) ON DELETE CASCADE, -- foreign key to referenced (child) AtomEntity CONSTRAINT FK_RootEntiry_Children__AtomEntity FOREIGN KEY (ChildAtomEntityId) REFERENCES AtomEntity (Id) ON DELETE CASCADE, ); CREATE TABLE ContainerEntity_Children ( ParentId UNIQUEIDENTIFIER NOT NULL, OrderIndex INT NOT NULL, ChildContainerEntityId UNIQUEIDENTIFIER NULL, ChildAtomEntityId UNIQUEIDENTIFIER NULL, ChildIsContainerEntity BIT NOT NULL, CONSTRAINT PK_ContainerEntity_Children PRIMARY KEY NONCLUSTERED (ParentId, OrderIndex), -- foreign key to parent ContainerEntity CONSTRAINT FK_ContainerEntity_Children__RootEntity FOREIGN KEY (ParentId) REFERENCES ContainerEntity (Id) ON DELETE CASCADE, -- foreign key to referenced (child) ContainerEntity CONSTRAINT FK_ContainerEntity_Children__ContainerEntity FOREIGN KEY (ChildContainerEntityId) REFERENCES ContainerEntity (Id) ON DELETE CASCADE, -- foreign key to referenced (child) AtomEntity CONSTRAINT FK_ContainerEntity_Children__AtomEntity FOREIGN KEY (ChildAtomEntityId) REFERENCES AtomEntity (Id) ON DELETE CASCADE, ); CREATE TRIGGER Delete_RootEntity_Children ON RootEntity_Children FOR DELETE AS DELETE FROM ContainerEntity WHERE Id IN (SELECT ChildContainerEntityId FROM deleted) DELETE FROM AtomEntity WHERE Id IN (SELECT ChildAtomEntityId FROM deleted) GO CREATE TRIGGER Delete_ContainerEntiy_Children ON ContainerEntity_Children FOR DELETE AS DELETE FROM ContainerEntity WHERE Id IN (SELECT ChildContainerEntityId FROM deleted) DELETE FROM AtomEntity WHERE Id IN (SELECT ChildAtomEntityId FROM deleted) GO

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  • Which is the most memory leak safe approach.

    - by MattC
    I have a table of frequently updated information. This is presented using a container div with a div for each row, each row containing 10 divs. I am using setInterval to call a an asmx webservice that returns some json formatted information. On the success callback I call $("#myContainer").empty(); on the container div and recreate the rows and 10 nested divs for each row's columns. This page may be left to run for a whole day, so I am wary of updating the DOM like this as I have noticed that memory does rise for the browser over time (IE8). The other approach I am considering is to add an idea to the row div. When new results process each item of data, look for the corresponding row, if it exists overwrite the data in each div. If it doesn't exist (new data for example), append the row. What approaches have others used for this sort of long lived pseudo realtime information display. TIA

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  • How should I provide access to this custom DAL?

    - by Casey
    I'm writing a custom DAL (VB.NET) for an ordering system project. I'd like to explain how it is coded now, and receive some alternate ideas to make coding against the DAL easier/more readable. The DAL is part of an n-tier (not n-layer) application, where each tier is in it's own assembly/DLL. The DAL consists of several classes that have specific behavior. For instance, there is an Order class that is responsible for retrieving and saving orders. Most of the classes have only two methods, a "Get" and a "Save," with multiple overloads for each. These classes are marked as Friend and are only visible to the DAL (which is in it's own assembly). In most cases, the DAL returns what I will call a "Data Object." This object is a class that contains only data and validation, and is located in a common assembly that both the BLL and DAL can read. To provide public access to the DAL, I currently have a static (module) class that has many shared members. A simplified version looks something like this: Public Class DAL Private Sub New End Sub Public Shared Function GetOrder(OrderID as String) as OrderData Dim OrderGetter as New OrderClass Return OrderGetter.GetOrder(OrderID) End Function End Class Friend Class OrderClass Friend Function GetOrder(OrderID as string) as OrderData End Function End Class The BLL would call for an order like this: DAL.GetOrder("123456") As you can imagine, this gets cumbersome very quickly. I'm mainly interested in structuring access to the DAL so that Intellisense is very intuitive. As it stands now, there are too many methods/functions in the DAL class with similar names. One idea I had is to break down the DAL into nested classes: Public Class DAL Private Sub New End Sub Public Class Orders Private Sub New End Sub Public Shared Function Get(OrderID as string) as OrderData End Function End Class End Class So the BLL would call like this: DAL.Orders.Get("12345") This cleans it up a bit, but it leaves a lot of classes that only have references to other classes, which I don't like for some reason. Without resorting to passing DB specific instructions (like where clauses) from BLL to DAL, what is the best or most common practice for providing a single point of access for the DAL?

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  • Relational vs. Dimensional Databases, what's the difference?

    - by grautur
    I'm trying to learn about OLAP and data warehousing, and I'm confused about the difference between relational and dimensional modeling. Is dimensional modeling basically relational modeling, but allowing for redundant/un-normalized data? For example, let's say I have historical sales data on (product, city, # sales). I understand that the following would be a relational point-of-view: Product | City | # Sales Apples, San Francisco, 400 Apples, Boston, 700 Apples, Seattle, 600 Oranges, San Francisco, 550 Oranges, Boston, 500 Oranges, Seattle, 600 While the following is a more dimensional point-of-view: Product | San Francisco | Boston | Seattle Apples, 400, 700, 600 Oranges, 550, 500, 600 But it seems like both points of view would nonetheless be implemented in an identical star schema: Fact table: Product ID, Region ID, # Sales Product dimension: Product ID, Product Name City dimension: City ID, City Name And it's not until you start adding some additional details to each dimension that the differences start popping up. For instance, if you wanted to track regions as well, a relational database would tend to have a separate region table, in order to keep everything normalized: City dimension: City ID, City Name, Region ID Region dimension: Region ID, Region Name, Region Manager, # Regional Stores While a dimensional database would allow for denormalization to keep the region data inside the city dimension, in order to make it easier to slice the data: City dimension: City ID, City Name, Region Name, Region Manager, # Regional Stores Is this correct?

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  • Examples of IOC/DI over Singleton

    - by Amitd
    Hi, Just started learning/reading about DI and IOC frameworks. Also I read many articles on SO and internet that say that one should prefer DI/IOC over singleton. Can anyone give/link examples of exactly how DI/IOC eliminates/solves the various issues regarding the Singleton pattern? (hopefully code and explanation for better understanding) Also given a system has already implemented Singleton pattern, how to refactor/implement DI/IOC for the same? (any examples for the same?) (Language/Framework no bars..C# would be helpful) Thanks

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  • looking for automated modeling tool for ASP.Net class diagramming

    - by alchemical
    I'm walking into a project with 500+ classes, and am wondering if anyone has had good experiences with automated modeling tools that can import from ASP.Net /C#? It would be a bonus if I could get an automated model based on all the objects called to completely load a single ASP.Net page, with relationships indicating which objects are calling out to which other ones, etc. Thanks for sharing your thoughts or recomendations.

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  • Should business objects be able to create their own DTOs?

    - by Sam
    Suppose I have the following class: class Camera { public Camera( double exposure, double brightness, double contrast, RegionOfInterest regionOfInterest) { this.exposure = exposure; this.brightness = brightness; this.contrast = contrast; this.regionOfInterest = regionOfInterest; } public void ConfigureAcquisitionFifo(IAcquisitionFifo acquisitionFifo) { // do stuff to the acquisition FIFO } readonly double exposure; readonly double brightness; readonly double contrast; readonly RegionOfInterest regionOfInterest; } ... and a DTO to transport the camera info across a service boundary (WCF), say, for viewing in a WinForms/WPF/Web app: using System.Runtime.Serialization; [DataContract] public class CameraData { [DataMember] public double Exposure { get; set; } [DataMember] public double Brightness { get; set; } [DataMember] public double Contrast { get; set; } [DataMember] public RegionOfInterestData RegionOfInterest { get; set; } } Now I can add a method to Camera to expose its data: class Camera { // blah blah public CameraData ToData() { var regionOfInterestData = regionOfInterest.ToData(); return new CameraData() { Exposure = exposure, Brightness = brightness, Contrast = contrast, RegionOfInterestData = regionOfInterestData }; } } or, I can create a method that requires a special IReporter to be passed in for the Camera to expose its data to. This removes the dependency on the Contracts layer (Camera no longer has to know about CameraData): class Camera { // beep beep I'm a jeep public void ExposeToReporter(IReporter reporter) { reporter.GetCameraInfo(exposure, brightness, contrast, regionOfInterest); } } So which should I do? I prefer the second, but it requires the IReporter to have a CameraData field (which gets changed by GetCameraInfo()), which feels weird. Also, if there is any even better solution, please share with me! I'm still an object-oriented newb.

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  • Sub-Schemas in SQL Server 2005/2008

    - by Maushu
    This is a simple question yet I was unable to find any information at all about this. Is it possible to have sub-schemas in SQL Server 2005/2008? Example: Having a HR (Human Resources) schema with a sub-schema called Training (with tables related to this). It would end up like HR.Training.* where * would be the tables.

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  • Collaboration Diagrams: how to represent setting a variable's and attribute's value to a specified v

    - by devoured elysium
    Let's assume I have a class called MyClass with an attribute called MyAttribute and a method called MyMethod(). Inside that method I'd like to have a variable called MyVariable. I'd like to set the value of MyVariable to "MyVariable" and MyAttribute to "MyAttribute" inside the call to MyMethod(). How can I do this in a Collaboration Diagram? I can't find any info of this kind on the internet and the book I'm studying from (Applying UML and Patterns) is very vague in the details. Thanks

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  • Building big, immutable objects without using constructors having long parameter lists

    - by Malax
    Hi StackOverflow! I have some big (more than 3 fields) Objects which can and should be immutable. Every time I run into that case i tend to create constructor abominations with long parameter lists. It doesn't feel right, is hard to use and readability suffers. It is even worse if the fields are some sort of collection type like lists. A simple addSibling(S s) would ease the object creation so much but renders the object mutable. What do you guys use in such cases? I'm on Scala and Java, but i think the problem is language agnostic as long as the language is object oriented. Solutions I can think of: "Constructor abominations with long parameter lists" The Builder Pattern Thanks for your input!

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  • where to enlist transaction with parent child delete (repository or bll)?

    - by Caroline Showden
    My app uses a business layer which calls a repository which uses linq to sql. I have an Item class that has an enum type property and an ItemDetail property. I need to implement a delete method that: (1) always delete the Item (2) if the item.type is XYZ and the ItemDetail is not null, delete the ItemDetail as well. My question is where should this logic be housed? If I have it in my business logic which I would prefer, this involves two separate repository calls, each of which uses a separate datacontext. I would have to wrap both calls is a System.Transaction which (in sql 2005) get promoted to a distributed transaction which is not ideal. I can move it all to a single repository call and the transaction will be handled implicitly by the datacontext but feel that this is really business logic so does not belong in the repository. Thoughts? Carrie

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  • Storing varchar(max) & varbinary(max) together - Problem?

    - by Tony Basallo
    I have an app that will have entries of both varchar(max) and varbinary(max) data types. I was considering putting these both in a separate table, together, even if only one of the two will be used at any given time. The question is whether storing them together has any impact on performance. Considering that they are stored in the heap, I'm thinking that having them together will not be a problem. However, the varchar(max) column will be probably have the text in row table option set. I couldn't find any performance testing or profiling while "googling bing," probably too specific a question? The SQL Server 2008 table looks like this: Id ParentId Version VersionDate StringContent - varchar(max) BinaryContent - varbinary(max) The app will decide which of the two columns to select for when the data is queried. The string column will much used much more frequently than the binary column - will this have any impact on performance?

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  • log in as a proxy for a certain user

    - by Samuel
    We have a requirement, wherein the administrative user needs to proxy in as a certain user in an environment where several users (Role: User) are managed by an administrator (Role: Admin). e.g If we have the following users in the database (admin, user1, user2, user3), we would want the admin to proxy as 'user2' and use the system in certain scenarios. Authentication in our web application is based username / password credentials, what mechanisms are available for the admin to proxy as 'user2' when he doesn't have the password for 'user2'. How can the application track such access for audit purposes to mention that 'admin' had proxied for 'user2' and performed certain actions. I am looking for suggestions on supporting this in our j2ee (jboss seam) web application.

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  • Best practices for managing limited client licenses/login

    - by MicSim
    I have a multi-user software solution (containing different applications, i.e. EXEs) that should allow only a limited number of concurrent users. It's designed to run in an intranet. I dont have a really good, satisfactory solution to the problem of counting the client licenses yet. The key requirements are: Multiple instances (starts) of the same application (= process) should count as only one client licence Starting different applications of the software solution should also count as only one (the same) client licence Application crash should not lead to orphaned used licences The above should work also for Terminal Server environments (all clients same IP, but different install folders) I'm looking for estabilished patterns, solutions, tips for managing used client licenses. Specific hints for the above sitaution are also welcome.

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  • To subclass or not to subclass

    - by poulenc
    I have three objects; Action, Issue and Risk. These all contain a nunber of common variables/attributes (for example: Description, title, Due date, Raised by etc.) and some specific fields (risk has probability). The question is: Should I create 3 separate classes Action, Risk and Issue each containing the repeat fields. Create a parent class "Abstract_Item" containing these fields and operations on them and then have Action, Risk and Issue subclass Abstract_Item. This would adhere to DRY principal.

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  • Single value data to multiple values of data in database relation

    - by Sofiane Merah
    I have such a hard time picturing this. I just don't have the brain to do it. I have a table called reports. --------------------------------------------- | report_id | set_of_bads | field1 | field2 | --------------------------------------------- | 123 | set1 | qwe | qwe | --------------------------------------------- | 321 | 123112 | ewq | ewq | --------------------------------------------- I have another table called bads. This table contains a list of bad data. ------------------------------------- | bad_id | set_it_belongs_to | field2 | field3 | ------------------------------------- | 1 | set1 | qwe | qwe | ------------------------------------- | 2 | set1 | qee | tte | ------------------------------------- | 3 | set1 | q44w | 3qwe | ------------------------------------- | 4 | 234 | qoow | 3qwe | ------------------------------------- Now I have set the first field of every table as the primary key. My question is, how do I connect the field set_of_bads to set_it_belongs_to in the bads table. This way if I want to get the entire set of data that is set1 by calling on the reports table I can do it. Example: hey reports table.. bring up the row that has the report_id 123. Okay thank you.. Now get all the rows from bads that has the set_of_bads value from the row with the report_id 123. Thanks.

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  • Making a DateTime field in SQLExpress database?

    - by Mike
    I'm putting together a simple test database to learn MVC with. I want to add a DateTime field to show when the record was CREATED. ID = int Name = Char DateCreated = (dateTime, DateTime2..?) I have a feeling that this type of DateTime capture can be done automatically - but that's all I have, a feeling. Can it be done? And if so how? While we're on the subject: if I wanted to include another field that captured the DateTime of when the record was LAST UPDATED how would I do that. I'm hoping to not do this manually. Many thanks Mike

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  • When should a member function have a const qualifier and when shouldn't it?

    - by SCFrench
    About six years ago, a software engineer named Harri Porten wrote this article, asking the question, "When should a member function have a const qualifier and when shouldn't it?" I found it to be the best write-up I could find of the issue, which I've been wrestling with more recently and which I think is not well covered in most discussions I've found on const correctness. Since a software information-sharing site as powerful as SO didn't exist back then, I'd like to resurrect the question here.

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  • How to store a numeric value which can have other statuses in a database?

    - by Jiho Han
    I need to store a set of numbers in a database which are imported from a spreadsheet. Sometimes a number is just a number. But in other times, a value can be "missing", "N/A", or blank and these all represent different things. What would be a good approach to store these numbers in the database? Originally I only had to account for N/A. So I made it -1 as I imported them (this only works if the number can never be negative obviously). I could use other negative numbers for other statuses. However, that seems clunky to me. Should I store the numbers as string then apply conversion at use time? Should I create a matching table that stores different statuses of each value?

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  • DDD and Client/Server apps

    - by Christophe Herreman
    I was wondering if any of you had successfully implemented DDD in a Client/Server app and would like to share some experiences. We are currently working on a smart client in Flex and a backend in Java. On the server we have a service layer exposed to the client that offers CRUD operations amongst some other service methods. I understand that in DDD these services should be repositories and services should be used to handle use cases that do not fit inside a repository. Right now, we mimic these services on the client behind an interface and inject implementations (Webservices, RMI, etc) via an IoC container. So some questions arise: should the server expose repositories to the client or do we need to have some sort of a facade (that is able to handle security for instance) should the client implement repositories (and DDD in general?) knowing that in the client, most of the logic is view related and real business logic lives on the server. All communication with the server happens asynchronously and we have a single threaded programming model on the client. how about mapping client to server objects and vice versa? We tried DTO's but reverted back to exposing the state of our objects and mapping directly to them. I know this is considered bad practice, but it saves us an incredible amount of time) In general I think a new generation of applications is coming with the growth of Flex, Silverlight, JavaFX and I'm curious how DDD fits into this.

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  • Credit card system implementation?

    - by Mark
    My site is going to have a credit system that basically works a lot like a credit card. Each user has an unlimited credit limit, but at the end of each week, they have to pay it off. For example, a user might make several purchases between March 1st and 7th, and then at the end of March 7th, they would be emailed an invoice that lists all their purchases during the week and a total that is due by the 14th. If they don't pay it off, their account is simply deactivated until they do. I'm just trying to wrap my head around how to implement this. I have a list of all their purchases, that's not a problem, but I'm just trying to figure out what to do with it. On the end of the 7th day, I could set up a cronjob to generate an invoice, which would basically have an id, and due date, and then I would need another many-to-many table to link all the purchases to the invoice. Then when a user adds money to their account, I guess it's applied against their current outstanding invoice? And what if they don't pay off their invoice by the time a new invoice rolls around, so now they have 2 outstanding ones, how do I know which to apply it against? Or do I make the cronjob check for any previous outstanding invoices, cancel them, and add a new item to the new invoice as "balance forward (+interest)"? How would you apply the money against an invoice? Would each payment have to be linked to an invoice, or could I just deposit it to their account credit, and then somehow figure out whats been paid and what hasn't? What if they pay in advance, before their invoice has been generated? Do I deduct it from their credit from the invoice upon generation, or at the end of the week when its due? There are so many ways to do this... Can anyone describe what approach they would take?

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