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  • Where and how to reference composite MVP components?

    - by Lea Hayes
    I am learning about the MVP (Model-View-Presenter) Passive View flavour of MVC. I intend to expose events from view interfaces rather than using the observer pattern to remove explicit coupling with presenter. Context: Windows Forms / Client-Side JavaScript. I am led to believe that the MVP (or indeed MVC in general) pattern can be applied at various levels of a user interface ranging from the main "Window" to an embedded "Text Field". For instance, the model to the text field is probably just a string whereas the model to the "Window" contains application specific view state (like a persons name which resides within the contained text field). Given a more complex scenario: Documentation viewer which contains: TOC navigation pane Document view Search pane Since each of these 4 user interface items are complex and can be reused elsewhere it makes sense to design these using MVP. Given that each of these user interface items comprises of 3 components; which component should be nested? where? who instantiates them? Idea #1 - Embed View inside View from Parent View public class DocumentationViewer : Form, IDocumentationViewerView { public DocumentationViewer() { ... // Unclear as to how model and presenter are injected... TocPane = new TocPaneView(); } protected ITocPaneView TocPane { get; private set; } } Idea #2 - Embed Presenter inside View from Parent View public class DocumentationViewer : Form, IDocumentationViewerView { public DocumentationViewer() { ... // This doesn't seem like view logic... var tocPaneModel = new TocPaneModel(); var tocPaneView = new TocPaneView(); TocPane = new TocPanePresenter(tocPaneModel, tocPaneView); } protected TocPanePresenter TocPane { get; private set; } } Idea #3 - Embed View inside View from Parent Presenter public class DocumentationViewer : Form, IDocumentationViewerView { ... // Part of IDocumentationViewerView: public ITocPaneView TocPane { get; set; } } public class DocumentationViewerPresenter { public DocumentationViewerPresenter(DocumentationViewerModel model, IDocumentationViewerView view) { ... var tocPaneView = new TocPaneView(); var tocPaneModel = new TocPaneModel(model.Toc); var tocPanePresenter = new TocPanePresenter(tocPaneModel, tocPaneView); view.TocPane = tocPaneView; } } Some better idea...

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  • Common header file for C++ and JavaScipt

    - by paperjam
    I have an app that runs a C++ server backend and Javascript on the client. I would like to define certain strings once only, for both pieces of code. For example, I might have a CSS class "row-hover" - I want to define this class name in one place only in case I change it later. Is there an easy way to include, or read, some sort of common definitions file into both C++ and JavaScript? Ideally as a compile / preprocessing step but any neat approach good.

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  • Fun with Declarative Components

    - by [email protected]
    Use case background I have been asked on a number of occasions if our selectOneChoice component could allow random text to be entered, as well as having a list of selections available. Unfortunately, the selectOneChoice component only allows entry via the dropdown selection list and doesn't allow text entry. I was thinking of possible solutions and thought that this might make a good example for using a declarative component.My initial idea My first thought was to use an af:inputText to allow the text entry, and an af:selectOneChoice with mode="compact" for the selections. To get it to layout horizontally, we would want to use an af:panelGroupLayout with layout="horizontal". To get the label for this to line up correctly, we'll need to wrap the af:panelGroupLayout with an af:panelLabelAndMessage. This is the basic structure: <af:panelLabelAndMessage> <af:panelGroupLayout layout="horizontal"> <af:inputText/> <af:selectOneChoice mode="compact"/> </af:panelgroupLayout></af:panelLabelAndMessage> Make it into a declarative component One of the steps to making a declarative component is deciding what attributes we want to be able to specify. To keep this example simple, let's just have: 'label' (the label of our declarative component)'value' (what we want to bind to the value of the input text)'items' (the select items in our dropdown) Here is the initial declarative component code (saved as file "inputTextWithChoice.jsff"): <?xml version='1.0' encoding='UTF-8'?><!-- Copyright (c) 2008, Oracle and/or its affiliates. All rights reserved. --><jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="2.1" xmlns:f="http://java.sun.com/jsf/core" xmlns:af="http://xmlns.oracle.com/adf/faces/rich"> <jsp:directive.page contentType="text/html;charset=utf-8"/> <af:componentDef var="attrs" componentVar="comp"> <af:xmlContent> <component xmlns="http://xmlns.oracle.com/adf/faces/rich/component"> <description>Input text with choice component.</description> <attribute> <description>Label</description> <attribute-name>label</attribute-name> <attribute-class>java.lang.String</attribute-class> </attribute> <attribute> <description>Value</description> <attribute-name>value</attribute-name> <attribute-class>java.lang.Object</attribute-class> </attribute> <attribute> <description>Choice Select Items Value</description> <attribute-name>items</attribute-name> <attribute-class>[[Ljavax.faces.model.SelectItem;</attribute-class> </attribute> </component> </af:xmlContent> <af:panelLabelAndMessage id="myPlm" label="#{attrs.label}" for="myIt"> <af:panelGroupLayout id="myPgl" layout="horizontal"> <af:inputText id="myIt" value="#{attrs.value}" partialTriggers="mySoc" label="myIt" simple="true" /> <af:selectOneChoice id="mySoc" label="mySoc" simple="true" mode="compact" value="#{attrs.value}" autoSubmit="true"> <f:selectItems id="mySIs" value="#{attrs.items}" /> </af:selectOneChoice> </af:panelGroupLayout> </af:panelLabelAndMessage> </af:componentDef></jsp:root> By having af:inputText and af:selectOneChoice both have the same value, then (assuming that this passed in as an EL expression) selecting something in the selectOneChoice will update the value in the af:inputText. To use this declarative component in a jspx page: <af:declarativeComponent id="myItwc" viewId="inputTextWithChoice.jsff" label="InputText with Choice" value="#{demoInput.choiceValue}" items="#{demoInput.selectItems}" /> Some problems arise At first glace, this seems to be functioning like we want it to. However, there is a side effect to having the af:inputText and af:selectOneChoice share a value, if one changes, so does the other. The problem here is that when we update the af:inputText to something that doesn't match one of the selections in the af:selectOneChoice, the af:selectOneChoice will set itself to null (since the value doesn't match one of the selections) and the next time the page is submitted, it will submit the null value and the af:inputText will be empty. Oops, we don't want that. Hmm, what to do. Okay, how about if we make sure that the current value is always available in the selection list. But, lets not render it if the value is empty. We also need to add a partialTriggers attribute so that this gets updated when the af:inputText is changed. Plus, we really don't want to select this item so let's disable it. <af:selectOneChoice id="mySoc" partialTriggers="myIt" label="mySoc" simple="true" mode="compact" value="#{attrs.value}" autoSubmit="true"> <af:selectItem id="mySI" label="Selected:#{attrs.value}" value="#{attrs.value}" disabled="true" rendered="#{!empty attrs.value}"/> <af:separator id="mySp" /> <f:selectItems id="mySIs" value="#{attrs.items}" /></af:selectOneChoice> That seems to be working pretty good. One minor issue that we probably can't do anything about is that when you enter something in the inputText and then click on the selectOneChoice, the popup is displayed, but then goes away because it has been replaced via PPR because we told it to with the partialTriggers="myIt". This is not that big a deal, since if you are entering something manually, you probably don't want to select something from the list right afterwards. Making it look like a single component. Now, let's play around a bit with the contentStyle of the af:inputText and the af:selectOneChoice so that the compact icon will layout inside the af:inputText, making it look more like an af:selectManyChoice. We need to add some padding-right to the af;inputText so there is space for the icon. These adjustments were for the Fusion FX skin. <af:inputText id="myIt" partialTriggers="mySoc" autoSubmit="true" contentStyle="padding-right: 15px;" value="#{attrs.value}" label="myIt" simple="true" /><af:selectOneChoice id="mySoc" partialTriggers="myIt" contentStyle="position: relative; top: -2px; left: -19px;" label="mySoc" simple="true" mode="compact" value="#{attrs.value}" autoSubmit="true"> <af:selectItem id="mySI" label="Selected:#{attrs.value}" value="#{attrs.value}" disabled="true" rendered="#{!empty attrs.value}"/> <af:separator id="mySp" /> <f:selectItems id="mySIs" value="#{attrs.items}" /></af:selectOneChoice> There you have it, a declarative component that allows for suggested selections, but also allows arbitrary text to be entered. This could be used for search field, where the 'items' attribute could be populated with popular searches. Lines of java code written: 0

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  • Design patterns to avoiding breaking the SRP while performing heavy data logging

    - by Kazark
    A class that performs both computations and data logging seems to have at least two responsibilities. Given a system for which the specifications require heavy data logging, what kind of design patterns or architectural patterns can be used to avoid bloating all the classes with logging calls every time they compute something? The decorator pattern be used (e.g. Interpolator decorated to LoggingInterpolator), but it seems that would result in a situation hardly more desirable in which almost every major class would need to be decorated with logging.

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  • Reduce Repetitive Initialization Code in C++ Applications by Using Delegating Constructors

    You're often required to repeat identical pieces of initialization code in every constructor of a class that declares multiple constructors. That's because unlike a few other programming languages, The C++ programming language doesn't allow a constructor to call another constructor of the same class. Luckily, this problem is about to disappear with the recent approval of a new C++0x feature called delegating constructors which are explained in this C++ tutorial.

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  • Fast programmatic compare of "timetable" data

    - by Brendan Green
    Consider train timetable data, where each service (or "run") has a data structure as such: public class TimeTable { public int Id {get;set;} public List<Run> Runs {get;set;} } public class Run { public List<Stop> Stops {get;set;} public int RunId {get;set;} } public class Stop { public int StationId {get;set;} public TimeSpan? StopTime {get;set;} public bool IsStop {get;set;} } We have a list of runs that operate against a particular line (the TimeTable class). Further, whilst we have a set collection of stations that are on a line, not all runs stop at all stations (that is, IsStop would be false, and StopTime would be null). Now, imagine that we have received the initial timetable, processed it, and loaded it into the above data structure. Once the initial load is complete, it is persisted into a database - the data structure is used only to load the timetable from its source and to persist it to the database. We are now receiving an updated timetable. The updated timetable may or may not have any changes to it - we don't know and are not told whether any changes are present. What I would like to do is perform a compare for each run in an efficient manner. I don't want to simply replace each run. Instead, I want to have a background task that runs periodically that downloads the updated timetable dataset, and then compares it to the current timetable. If differences are found, some action (not relevant to the question) will take place. I was initially thinking of some sort of checksum process, where I could, for example, load both runs (that is, the one from the new timetable received and the one that has been persisted to the database) into the data structure and then add up all the hour components of the StopTime, and all the minute components of the StopTime and compare the results (i.e. both the sum of Hours and sum of Minutes would be the same, and differences introduced if a stop time is changed, a stop deleted or a new stop added). Would that be a valid way to check for differences, or is there a better way to approach this problem? I can see a problem that, for example, one stop is changed to be 2 minutes earlier, and another changed to be 2 minutes later would have a net zero change. Or am I over thinking this, and would it just be simpler to brute check all stops to ensure that The updated run stops at the same stations; and Each stop is at the same time

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  • Design Anti-Patterns - C# - Do you call this a God object?

    - by Reddy S R
    I am writing Portfolio module for my web site and it has 3 components. Gallery Category, Gallery, & Gallery Images. I am doing all the request handling, (creating, reading, updating, other), for the above 3 components in 1 class, Portfolio. DB handling jobs for Portfolio module is done in another file. My question is, even just for request handling purpose, can you do all the operations in 1 class? -Reddy

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  • Oracle Linux Training Across Five Continents

    - by Antoinette O'Sullivan
    The Oracle Linux System Administration course, a top selling course, provides you with a broad selection of key competencies you need to be a great Linux system administrator. And you can now take this course from your desk or in classrooms across all five contents. You can take this 5-day instructor-led course through the follow delivery methods: Training-on-Demand: Start training within 24 hours of registering. You following lecture material at your own pace via streaming video and book time on a lab environment to suit your schedule. Live-Virtual Event: Follow a live event from your own desk, no travel required. You can choose from a selection of events on the schedule to suit a different time zones. In-Class Event: Travel to an education center to take this course. Below is a selection of the in-class events already on the schedule. AFRICA  Location  Date  Delivery Language  Nairobi, Kenya  13 October 2014  English  Johannesburg, South Africa  24 November 2014  English AMERICA  Location  Date  Delivery Language  Mississauga, Canada  27 October 2014  English  Chicago, IL, United States  13 October 2014  English  Roseville, MN, United States  13 October 2014  English ASIA  Location  Date  Delivery  Jakarta, Indonesia  20 October 2014  English  Petaling Jaya, Malaysia  25 August 2014  English  Kuala Lumpur, Malaysia  8 December 2014  English  Istanbul, Turkey  10 November 2014  Turkish   Dubai, United Arab Emirates  4 January 2015  English AUSTRALIA  Location  Date  Delivery Language  Canberra, Australia  20 October 2014  English  Melbourne, Australia  20 October 2014  English EUROPE  Location  Date  Delivery Language  Paris, France  6 October 2014  French  Milan, Italy  20 October 2014  Italian  Rome, Italy  8 September 2014  Italian  Bucharest, Romania  27 October 2014  Romanian  Madrid, Spain  1 September 2014  Spanish The Oracle Linux System Administration course is the recommended training course to prepare for you for the Oracle Linux 5 & 6 System Administrator OCA certification exam. Those who have acquired the skills provided in the Oracle Linux System Administration course, can advance their learning by taking the Oracle Linux Advanced Administration course. You can take this 5-day instructor led course as a live-virtual event or an in-class event. Below is a selection of the in-class events on the schedule:  Location  Date  Delivery Language  Jakarta, Indonesia  27 October 2014  English  Kuala Lumpur, Malaysia  6 October 2014  English  Bangkok, Thailand  20 October 2014  English  Belmont, CA, United States  15 September 2014  English For information on the Oracle Linux curriculum, go to http://oracle.com/education/linux.

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  • Calling methods on Objects

    - by Mashael
    Let's say we have a class called 'Automobile' and we have an instance of that class called 'myCar'. I would like to ask why do we need to put the values that our methods return in a variable for the object? Why just don't we call the method? For example: Why should we write: string message = myCar.SpeedMessage(); Console.WriteLine(message); instead of: Console.WriteLine(myCar.SpeedMessage());

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  • Best practices for logging and tracing in .NET

    - by Levidad
    I've been reading a lot about tracing and logging, trying to find some golden rule for best practices in the matter, but there isn't any. People say that good programmers produce good tracing, but put it that way and it has to come from experience. I've also read similar questions in here and through the internet and they are not really the same thing I am asking or do not have a satisfying answer, maybe because the questions lack some detail. So, folks say that tracing should sort of replicate the experience of debugging the application in cases where you can't attach a debugger. It should provide enough context so that you can see which path is taken at each control point in the application. Going deeper, you can even distinguish between tracing and event logging, in that "event logging is different from tracing in that it captures major states rather than detailed flow of control". Now, say I want to do my tracing and logging using only the standard .NET classes, those in the System.Diagnostics namespace. I figured that the TraceSource class is better for the job than the static Trace class, because I want to differentiate among the trace levels and using the TraceSource class I can pass in a parameter informing the event type, while using the Trace class I must use Trace.WriteLineIf and then verify things like SourceSwitch.TraceInformation and SourceSwitch.TraceErrors, and it doesn't even have properties like TraceVerbose or TraceStart. With all that in mind, would you consider a good practice to do as follows: Trace a "Start" event when begining a method, which should represent a single logical operation or a pipeline, along with a string representation of the parameter values passed in to the method. Trace an "Information" event when inserting an item into the database. Trace an "Information" event when taking one path or another in an important if/else statement. Trace a "Critical" or "Error" in a catch block depending on weather this is a recoverable error. Trace a "Stop" event when finishing the execution of the method. And also, please clarify when best to trace Verbose and Warning event types. If you have examples of code with nice trace/logging and are willing to share, that would be excelent. Note: I've found some good information here, but still not what I am looking for: http://msdn.microsoft.com/en-us/magazine/ff714589.aspx Thanks in advance!

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  • Accessing Repositories from Domain

    - by Paul T Davies
    Say we have a task logging system, when a task is logged, the user specifies a category and the task defaults to a status of 'Outstanding'. Assume in this instance that Category and Status have to be implemented as entities. Normally I would do this: Application Layer: public class TaskService { //... public void Add(Guid categoryId, string description) { var category = _categoryRepository.GetById(categoryId); var status = _statusRepository.GetById(Constants.Status.OutstandingId); var task = Task.Create(category, status, description); _taskRepository.Save(task); } } Entity: public class Task { //... public static void Create(Category category, Status status, string description) { return new Task { Category = category, Status = status, Description = descrtiption }; } } I do it like this because I am consistently told that entities should not access the repositories, but it would make much more sense to me if I did this: Entity: public class Task { //... public static void Create(Category category, string description) { return new Task { Category = category, Status = _statusRepository.GetById(Constants.Status.OutstandingId), Description = descrtiption }; } } The status repository is dependecy injected anyway, so there is no real dependency, and this feels more to me thike it is the domain that is making thedecision that a task defaults to outstanding. The previous version feels like it is the application layeer making that decision. Any why are repository contracts often in the domain if this should not be a posibility? Here is a more extreme example, here the domain decides urgency: Entity: public class Task { //... public static void Create(Category category, string description) { var task = new Task { Category = category, Status = _statusRepository.GetById(Constants.Status.OutstandingId), Description = descrtiption }; if(someCondition) { if(someValue > anotherValue) { task.Urgency = _urgencyRepository.GetById (Constants.Urgency.UrgentId); } else { task.Urgency = _urgencyRepository.GetById (Constants.Urgency.SemiUrgentId); } } else { task.Urgency = _urgencyRepository.GetById (Constants.Urgency.NotId); } return task; } } There is no way you would want to pass in all possible versions of Urgency, and no way you would want to calculate this business logic in the application layer, so surely this would be the most appropriate way? So is this a valid reason to access repositories from the domain?

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  • Rotate/Translate object in local space

    - by Mathias Hölzl
    I am just trying to create a movementcontroller class for game entities. These class should transform the entity affected by the mouse and keyboard input. I am able to calculate the changed rotation and the new globalPosition. Then I multiply: newGlobalMatrix = changedRotationMatrix * oldGlobalMatrix; newGlobalMatrix = MatrixSetPosition(newPosition); The problem is that the object rotates around the global axis and not around the local axis. I use XNAMath for the matrix calculation.

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  • Three Ways to Take Official MySQL for Database Administrators course

    - by Antoinette O'Sullivan
    The MySQL for Database Administrators course is a 5 day course that teaches the key skills essential for MySQL Database Administrators. You can take this course in one of the following three ways: Training on Demand: Get Instructor-led training within 24 hours through streaming-video from your desk. Live Virtual Class: Live instructor-led training from your desk. Over 1000! LVC events on the schedule for the MySQL for Database Administrator course. In Class: See below for a selection of locations where you can take this training For more information on this course or teaching schedule, go to the Oracle University portal and click on MySQL or search under your country/location. A selection of the In-Class schedule for the MySQL for Database Administrator course:  Location  Date  Delivery Language  Mechelen, Belgium  10 Sept 2012  English  Prague, Czech Republic  27 Aug 2012  Czech  Nice, France  24 Sept 2012  French  Paris, France  24 Sept 2012  French  Strasbourg, France  10 Sept 2012  French  Dresden, Germany  20 Aug 2012  German  Gummersbach, Germany  27 Aug 2012  German  Hamburg, Germany  23 July 2012  German  Munich, Germany  16 July 2012  German  Munster, Germany  6 Aug 2012  German  Stuttgart, Germany  9 July 2012  German  London, Great Britan  9 July 2012  English  Belfast, Ireland  27 Aug 2012  English  Rome, Italy  30 July 2012  Italian  Windhof, Luxembourg  26 Nov 2012  English  Nieuwegein, Netherlands  1 Oct 2012  English  Oslo, Norway  10 Sept 2012  English  Warsaw, Poland  9 July 2012  Polish  Lisbon, Portugal  3 Sept 2012  European Portugese  Madrid, Spain  25 Jun 2012  Spanish  Baden Dattwil, Switzerland  19 Nov 2012  German  Zurick, Switzerland  8 Aug 2012  German  Istanbul, Turkey  27 Aug 2012  Turkish  Petaling Jaya, Malaysia  25 Jul 2012  English  Singapore  16 July 2012  English  Brisbane, Australia  30 July 2012  English  Bangkok, Thailand  30 July 2012  Thai  Edmonton, Canada  10 Sept 2012  English  Vancouver, Canada  10 Sept 2012  English  Ottawa, Canada  30 July 2012  English  Toronto, Canada  30 July 2012  English  Montreal, Canada  30 July 2012  English  Mexico City, Mexico  25 Jun 2012  Spanish With these three delivery options and an impressive LVC and In-Class schedule you should find an event to suit your needs. If you are interested in another date or location you can register your interest on the Oracle University portal.

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  • What are the software design essentials? [closed]

    - by Craig Schwarze
    I've decided to create a 1 page "cheat sheet" of essential software design principles for my programmers. It doesn't explain the principles in any great depth, but is simply there as a reference and a reminder. Here's what I've come up with - I would welcome your comments. What have I left out? What have I explained poorly? What is there that shouldn't be? Basic Design Principles The Principle of Least Surprise – your solution should be obvious, predictable and consistent. Keep It Simple Stupid (KISS) - the simplest solution is usually the best one. You Ain’t Gonna Need It (YAGNI) - create a solution for the current problem rather than what might happen in the future. Don’t Repeat Yourself (DRY) - rigorously remove duplication from your design and code. Advanced Design Principles Program to an interface, not an implementation – Don’t declare variables to be of a particular concrete class. Rather, declare them to an interface, and instantiate them using a creational pattern. Favour composition over inheritance – Don’t overuse inheritance. In most cases, rich behaviour is best added by instantiating objects, rather than inheriting from classes. Strive for loosely coupled designs – Minimise the interdependencies between objects. They should be able to interact with minimal knowledge of each other via small, tightly defined interfaces. Principle of Least Knowledge – Also called the “Law of Demeter”, and is colloquially summarised as “Only talk to your friends”. Specifically, a method in an object should only invoke methods on the object itself, objects passed as a parameter to the method, any object the method creates, any components of the object. SOLID Design Principles Single Responsibility Principle – Each class should have one well defined purpose, and only one reason to change. This reduces the fragility of your code, and makes it much more maintainable. Open/Close Principle – A class should be open to extension, but closed to modification. In practice, this means extracting the code that is most likely to change to another class, and then injecting it as required via an appropriate pattern. Liskov Substitution Principle – Subtypes must be substitutable for their base types. Essentially, get your inheritance right. In the classic example, type square should not inherit from type rectangle, as they have different properties (you can independently set the sides of a rectangle). Instead, both should inherit from type shape. Interface Segregation Principle – Clients should not be forced to depend upon methods they do not use. Don’t have fat interfaces, rather split them up into smaller, behaviour centric interfaces. Dependency Inversion Principle – There are two parts to this principle: High-level modules should not depend on low-level modules. Both should depend on abstractions. Abstractions should not depend on details. Details should depend on abstractions. In modern development, this is often handled by an IoC (Inversion of Control) container.

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  • Challenge: Learn One New Thing Today

    - by BuckWoody
    Most of us know that there's a lot to learn. I'm teaching a class this morning, and even on the subject where I'm the "expert" (that word always makes me nervous!) I still have a lot to learn. To learn, sometimes I take a class, read a book, or carve out a large chunk of time so that I can fully grasp the subject. But since I've been working, I really don't have a lot of opportunities to do that. Like you, I'm really busy. So what I've been able to learn is to take just a few moments each day and learn something new about SQL Server. I thought I would share that process here. First, I started with an outline of the product. You can use Books Online, a college class syllabus, a training class outline, or a comprehensive book table of contents. Then I checked off the things I felt I knew a little about. Sure, I'll come back around to those, but I want to be as efficient as I can. I then trolled various checklists to see what I needed to know about the subjects I didn't have checked off. From there (I'm doing all this in a notepad, and then later in OneNote when that came out) I developed a block of text for that subject. Every time I ran across a book, article, web site or recording on that topic I wrote that reference down. Later I went back and quickly looked over those resources and tried to figure out how I could parcel it out - 10 minutes for this one, a free seminar (like the one I'm teaching today - ironic) takes 4 hours, a web site takes an hour to grok, that sort of thing.  Then all I did was figure out how much time each day I'll give to training. Sure, it literally may be ten minutes, but it adds up. One final thing - as I used something I learned, I came back and made notes in that topic. You learn to play the piano not just from a book, but by playing the piano, after all. If you don't use what you learn, you'll lose it. So if you're interested in getting better at SQL Server, and you're willing to do a little work, try out this method. Leave a note here for others to encourage them.  Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • Designing for an algorithm that reports progress

    - by Stefano Borini
    I have an iterative algorithm and I want to print the progress. However, I may also want it not to print any information, or to print it in a different way, or do other logic. In an object oriented language, I would perform the following solutions: Solution 1: virtual method have the algorithm class MyAlgoClass which implements the algo. The class also implements a virtual reportIteration(iterInfo) method which is empty and can be reimplemented. Subclass the MyAlgoClass and override reportIteration so that it does what it needs to do. This solution allows you to carry additional information (for example, the file unit) in the reimplemented class. I don't like this method because it clumps together two functionalities that may be unrelated, but in GUI apps it may be ok. Solution 2: observer pattern the algorithm class has a register(Observer) method, keeps a list of the registered observers and takes care of calling notify() on each of them. Observer::notify() needs a way to get the information from the Subject, so it either has two parameters, one with the Subject and the other with the data the Subject may pass, or just the Subject and the Observer is now in charge of querying it to fetch the relevant information. Solution 3: callbacks I tend to see the callback method as a lightweight observer. Instead of passing an object, you pass a callback, which may be a plain function, but also an instance method in those languages that allow it (for example, in python you can because passing an instance method will remain bound to the instance). C++ however does not allow it, because if you pass a pointer to an instance method, this will not be defined. Please correct me on this regard, my C++ is quite old. The problem with callbacks is that generally you have to pass them together with the data you want the callback to be invoked with. Callbacks don't store state, so you have to pass both the callback and the state to the Subject in order to find it at callback execution, together with any additional data the Subject may provide about the event is reporting. Question My question is relative to the fact that I need to implement the opening problem in a language that is not object oriented, namely Fortran 95, and I am fighting with my usual reasoning which is based on python assumptions and style. I think that in Fortran the concept is similar to C, with the additional trouble that in C you can store a function pointer, while in Fortran 95 you can only pass it around. Do you have any comments, suggestions, tips, and quirks on this regard (in C, C++, Fortran and python, but also in any other language, so to have a comparison of language features that can be exploited on this regard) on how to design for an algorithm that must report progress to some external entity, using state from both the algorithm and the external entity ?

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  • How to create Custom ListForm WebPart

    - by DipeshBhanani
    Mostly all who works extensively on SharePoint (including meJ) don’t like to use out-of-box list forms (DispForm.aspx, EditForm.aspx, NewForm.aspx) as interface. Actually these OOB list forms bind hands of developers for the customization. It gives headache to developers to add just one post back event, for a dropdown field and to populate other fields in NewForm.aspx or EditForm.aspx. On top of that clients always ask such stuff. So here I am going to give you guys a flight for SharePoint Customization world. In this blog, I will explain, how to create CustomListForm WebPart. In my next blogs, I am going to explain easy deployment of List Forms through features and last, guidance on using SharePoint web controls. 1.       First thing, create a class library project through Visual Studio and inherit the class with WebPart class.     public class CustomListForm : WebPart   2.       Declare the public variables and properties which we are going to use throughout the class. You will get to know these once you see them in use.         #region "Variable Declaration"           Table spTableCntl;         FormToolBar formToolBar;         Literal ltAlertMessage;         Guid SiteId;         Guid ListId;         int ItemId;         string ListName;           #endregion           #region "Properties"           SPControlMode _ControlMode = SPControlMode.New;         [Personalizable(PersonalizationScope.Shared),          WebBrowsable(true),          WebDisplayName("Control Mode"),          WebDescription("Set Control Mode"),          DefaultValue(""),          Category("Miscellaneous")]         public SPControlMode ControlMode         {             get { return _ControlMode; }             set { _ControlMode = value; }         }           #endregion     The property “ControlMode” is used to identify the mode of the List Form. The property is of type SPControlMode which is an enum type with values (Display, Edit, New and Invalid). When we will add this WebPart to DispForm.aspx, EditForm.aspx and NewForm.aspx, we will set the WebPart property “ControlMode” to Display, Edit and New respectively.     3.       Now, we need to override the CreateChildControl method and write code to manually add SharePoint Web Controls related to each list fields as well as ToolBar controls.         protected override void CreateChildControls()         {             base.CreateChildControls();               try             {                 SiteId = SPContext.Current.Site.ID;                 ListId = SPContext.Current.ListId;                 ListName = SPContext.Current.List.Title;                   if (_ControlMode == SPControlMode.Display || _ControlMode == SPControlMode.Edit)                     ItemId = SPContext.Current.ItemId;                   SPSecurity.RunWithElevatedPrivileges(delegate()                 {                     using (SPSite site = new SPSite(SiteId))                     {                         //creating a new SPSite with credentials of System Account                         using (SPWeb web = site.OpenWeb())                         {                               //<Custom Code for creating form controls>                         }                     }                 });             }             catch (Exception ex)             {                 ShowError(ex, "CreateChildControls");             }         }   Here we are assuming that we are developing this WebPart to plug into List Forms. Hence we will get the List Id and List Name from the current context. We can have Item Id only in case of Display and Edit Mode. We are putting our code into “RunWithElevatedPrivileges” to elevate privileges to System Account. Now, let’s get deep down into the main code and expand “//<Custom Code for creating form controls>”. Before initiating any SharePoint control, we need to set context of SharePoint web controls explicitly so that it will be instantiated with elevated System Account user. Following line does the job.     //To create SharePoint controls with new web object and System Account credentials     SPControl.SetContextWeb(Context, web);   First thing, let’s add main table as container for all controls.     //Table to render webpart     Table spTableMain = new Table();     spTableMain.CellPadding = 0;     spTableMain.CellSpacing = 0;     spTableMain.Width = new Unit(100, UnitType.Percentage);     this.Controls.Add(spTableMain);   Now we need to add Top toolbar with Save and Cancel button at top as you see in the below screen shot.       // Add Row and Cell for Top ToolBar     TableRow spRowTopToolBar = new TableRow();     spTableMain.Rows.Add(spRowTopToolBar);     TableCell spCellTopToolBar = new TableCell();     spRowTopToolBar.Cells.Add(spCellTopToolBar);     spCellTopToolBar.Width = new Unit(100, UnitType.Percentage);         ToolBar toolBarTop = (ToolBar)Page.LoadControl("/_controltemplates/ToolBar.ascx");     toolBarTop.CssClass = "ms-formtoolbar";     toolBarTop.ID = "toolBarTbltop";     toolBarTop.RightButtons.SeparatorHtml = "<td class=ms-separator> </td>";       if (_ControlMode != SPControlMode.Display)     {         SaveButton btnSave = new SaveButton();         btnSave.ControlMode = _ControlMode;         btnSave.ListId = ListId;           if (_ControlMode == SPControlMode.New)             btnSave.RenderContext = SPContext.GetContext(web);         else         {             btnSave.RenderContext = SPContext.GetContext(this.Context, ItemId, ListId, web);             btnSave.ItemContext = SPContext.GetContext(this.Context, ItemId, ListId, web);             btnSave.ItemId = ItemId;         }         toolBarTop.RightButtons.Controls.Add(btnSave);     }       GoBackButton goBackButtonTop = new GoBackButton();     toolBarTop.RightButtons.Controls.Add(goBackButtonTop);     goBackButtonTop.ControlMode = SPControlMode.Display;       spCellTopToolBar.Controls.Add(toolBarTop);   Here we have use “SaveButton” and “GoBackButton” which are internal SharePoint web controls for save and cancel functionality. I have set some of the properties of Save Button with if-else condition because we will not have Item Id in case of New Mode. Item Id property is used to identify which SharePoint List Item need to be saved. Now, add Form Toolbar to the page which contains “Attach File”, “Delete Item” etc buttons.       // Add Row and Cell for FormToolBar     TableRow spRowFormToolBar = new TableRow();     spTableMain.Rows.Add(spRowFormToolBar);     TableCell spCellFormToolBar = new TableCell();     spRowFormToolBar.Cells.Add(spCellFormToolBar);     spCellFormToolBar.Width = new Unit(100, UnitType.Percentage);       FormToolBar formToolBar = new FormToolBar();     formToolBar.ID = "formToolBar";     formToolBar.ListId = ListId;     if (_ControlMode == SPControlMode.New)         formToolBar.RenderContext = SPContext.GetContext(web);     else     {         formToolBar.RenderContext = SPContext.GetContext(this.Context, ItemId, ListId, web);         formToolBar.ItemContext = SPContext.GetContext(this.Context, ItemId, ListId, web);         formToolBar.ItemId = ItemId;     }     formToolBar.ControlMode = _ControlMode;     formToolBar.EnableViewState = true;       spCellFormToolBar.Controls.Add(formToolBar);     The ControlMode property will take care of which button to be displayed on the toolbar. E.g. “Attach files”, “Delete Item” in new/edit forms and “New Item”, “Edit Item”, “Delete Item”, “Manage Permissions” etc in display forms. Now add main section which contains form field controls.     //Create Form Field controls and add them in Table "spCellCntl"     CreateFieldControls(web);     //Add public variable "spCellCntl" containing all form controls to the page     spRowCntl.Cells.Add(spCellCntl);     spCellCntl.Width = new Unit(100, UnitType.Percentage);     spCellCntl.Controls.Add(spTableCntl);       //Add a Blank Row with height of 5px to render space between ToolBar table and Control table     TableRow spRowLine1 = new TableRow();     spTableMain.Rows.Add(spRowLine1);     TableCell spCellLine1 = new TableCell();     spRowLine1.Cells.Add(spCellLine1);     spCellLine1.Height = new Unit(5, UnitType.Pixel);     spCellLine1.Controls.Add(new LiteralControl("<IMG SRC='/_layouts/images/blank.gif' width=1 height=1 alt=''>"));       //Add Row and Cell for Form Controls Section     TableRow spRowCntl = new TableRow();     spTableMain.Rows.Add(spRowCntl);     TableCell spCellCntl = new TableCell();       //Create Form Field controls and add them in Table "spCellCntl"     CreateFieldControls(web);     //Add public variable "spCellCntl" containing all form controls to the page     spRowCntl.Cells.Add(spCellCntl);     spCellCntl.Width = new Unit(100, UnitType.Percentage);     spCellCntl.Controls.Add(spTableCntl);       TableRow spRowLine2 = new TableRow();     spTableMain.Rows.Add(spRowLine2);     TableCell spCellLine2 = new TableCell();     spRowLine2.Cells.Add(spCellLine2);     spCellLine2.CssClass = "ms-formline";     spCellLine2.Controls.Add(new LiteralControl("<IMG SRC='/_layouts/images/blank.gif' width=1 height=1 alt=''>"));       // Add Blank row with height of 5 pixel     TableRow spRowLine3 = new TableRow();     spTableMain.Rows.Add(spRowLine3);     TableCell spCellLine3 = new TableCell();     spRowLine3.Cells.Add(spCellLine3);     spCellLine3.Height = new Unit(5, UnitType.Pixel);     spCellLine3.Controls.Add(new LiteralControl("<IMG SRC='/_layouts/images/blank.gif' width=1 height=1 alt=''>"));   You can add bottom toolbar also to get same look and feel as OOB forms. I am not adding here as the blog will be much lengthy. At last, you need to write following lines to allow unsafe updates for Save and Delete button.     // Allow unsafe update on web for save button and delete button     if (this.Page.IsPostBack && this.Page.Request["__EventTarget"] != null         && (this.Page.Request["__EventTarget"].Contains("IOSaveItem")         || this.Page.Request["__EventTarget"].Contains("IODeleteItem")))     {         SPContext.Current.Web.AllowUnsafeUpdates = true;     }   So that’s all. We have finished writing Custom Code for adding field control. But something most important is skipped. In above code, I have called function “CreateFieldControls(web);” to add SharePoint field controls to the page. Let’s see the implementation of the function:     private void CreateFieldControls(SPWeb pWeb)     {         SPList listMain = pWeb.Lists[ListId];         SPFieldCollection fields = listMain.Fields;           //Main Table to render all fields         spTableCntl = new Table();         spTableCntl.BorderWidth = new Unit(0);         spTableCntl.CellPadding = 0;         spTableCntl.CellSpacing = 0;         spTableCntl.Width = new Unit(100, UnitType.Percentage);         spTableCntl.CssClass = "ms-formtable";           SPContext controlContext = SPContext.GetContext(this.Context, ItemId, ListId, pWeb);           foreach (SPField listField in fields)         {             string fieldDisplayName = listField.Title;             string fieldInternalName = listField.InternalName;               //Skip if the field is system field or hidden             if (listField.Hidden || listField.ShowInVersionHistory == false)                 continue;               //Skip if the control mode is display and field is read-only             if (_ControlMode != SPControlMode.Display && listField.ReadOnlyField == true)                 continue;               FieldLabel fieldLabel = new FieldLabel();             fieldLabel.FieldName = listField.InternalName;             fieldLabel.ListId = ListId;               BaseFieldControl fieldControl = listField.FieldRenderingControl;             fieldControl.ListId = ListId;             //Assign unique id using Field Internal Name             fieldControl.ID = string.Format("Field_{0}", fieldInternalName);             fieldControl.EnableViewState = true;               //Assign control mode             fieldLabel.ControlMode = _ControlMode;             fieldControl.ControlMode = _ControlMode;             switch (_ControlMode)             {                 case SPControlMode.New:                     fieldLabel.RenderContext = SPContext.GetContext(pWeb);                     fieldControl.RenderContext = SPContext.GetContext(pWeb);                     break;                 case SPControlMode.Edit:                 case SPControlMode.Display:                     fieldLabel.RenderContext = controlContext;                     fieldLabel.ItemContext = controlContext;                     fieldLabel.ItemId = ItemId;                       fieldControl.RenderContext = controlContext;                     fieldControl.ItemContext = controlContext;                     fieldControl.ItemId = ItemId;                     break;             }               //Add row to display a field row             TableRow spCntlRow = new TableRow();             spTableCntl.Rows.Add(spCntlRow);               //Add the cells for containing field lable and control             TableCell spCellLabel = new TableCell();             spCellLabel.Width = new Unit(30, UnitType.Percentage);             spCellLabel.CssClass = "ms-formlabel";             spCntlRow.Cells.Add(spCellLabel);             TableCell spCellControl = new TableCell();             spCellControl.Width = new Unit(70, UnitType.Percentage);             spCellControl.CssClass = "ms-formbody";             spCntlRow.Cells.Add(spCellControl);               //Add the control to the table cells             spCellLabel.Controls.Add(fieldLabel);             spCellControl.Controls.Add(fieldControl);               //Add description if there is any in case of New and Edit Mode             if (_ControlMode != SPControlMode.Display && listField.Description != string.Empty)             {                 FieldDescription fieldDesc = new FieldDescription();                 fieldDesc.FieldName = fieldInternalName;                 fieldDesc.ListId = ListId;                 spCellControl.Controls.Add(fieldDesc);             }               //Disable Name(Title) in Edit Mode             if (_ControlMode == SPControlMode.Edit && fieldDisplayName == "Name")             {                 TextBox txtTitlefield = (TextBox)fieldControl.Controls[0].FindControl("TextField");                 txtTitlefield.Enabled = false;             }         }         fields = null;     }   First of all, I have declared List object and got list fields in field collection object called “fields”. Then I have added a table for the container of all controls and assign CSS class as "ms-formtable" so that it gives consistent look and feel of SharePoint. Now it’s time to navigate through all fields and add them if required. Here we don’t need to add hidden or system fields. We also don’t want to display read-only fields in new and edit forms. Following lines does this job.             //Skip if the field is system field or hidden             if (listField.Hidden || listField.ShowInVersionHistory == false)                 continue;               //Skip if the control mode is display and field is read-only             if (_ControlMode != SPControlMode.Display && listField.ReadOnlyField == true)                 continue;   Let’s move to the next line of code.             FieldLabel fieldLabel = new FieldLabel();             fieldLabel.FieldName = listField.InternalName;             fieldLabel.ListId = ListId;               BaseFieldControl fieldControl = listField.FieldRenderingControl;             fieldControl.ListId = ListId;             //Assign unique id using Field Internal Name             fieldControl.ID = string.Format("Field_{0}", fieldInternalName);             fieldControl.EnableViewState = true;               //Assign control mode             fieldLabel.ControlMode = _ControlMode;             fieldControl.ControlMode = _ControlMode;   We have used “FieldLabel” control for displaying field title. The advantage of using Field Label is, SharePoint automatically adds red star besides field label to identify it as mandatory field if there is any. Here is most important part to understand. The “BaseFieldControl”. It will render the respective web controls according to type of the field. For example, if it’s single line of text, then Textbox, if it’s look up then it renders dropdown. Additionally, the “ControlMode” property tells compiler that which mode (display/edit/new) controls need to be rendered with. In display mode, it will render label with field value. In edit mode, it will render respective control with item value and in new mode it will render respective control with empty value. Please note that, it’s not always the case when dropdown field will be rendered for Lookup field or Choice field. You need to understand which controls are rendered for which list fields. I am planning to write a separate blog which I hope to publish it very soon. Moreover, we also need to assign list field specific properties like List Id, Field Name etc to identify which SharePoint List field is attached with the control.             switch (_ControlMode)             {                 case SPControlMode.New:                     fieldLabel.RenderContext = SPContext.GetContext(pWeb);                     fieldControl.RenderContext = SPContext.GetContext(pWeb);                     break;                 case SPControlMode.Edit:                 case SPControlMode.Display:                     fieldLabel.RenderContext = controlContext;                     fieldLabel.ItemContext = controlContext;                     fieldLabel.ItemId = ItemId;                       fieldControl.RenderContext = controlContext;                     fieldControl.ItemContext = controlContext;                     fieldControl.ItemId = ItemId;                     break;             }   Here, I have separate code for new mode and Edit/Display mode because we will not have Item Id to assign in New Mode. We also need to set CSS class for cell containing Label and Controls so that those controls get rendered with SharePoint theme.             spCellLabel.CssClass = "ms-formlabel";             spCellControl.CssClass = "ms-formbody";   “FieldDescription” control is used to add field description if there is any.    Now it’s time to add some more customization,               //Disable Name(Title) in Edit Mode             if (_ControlMode == SPControlMode.Edit && fieldDisplayName == "Name")             {                 TextBox txtTitlefield = (TextBox)fieldControl.Controls[0].FindControl("TextField");                 txtTitlefield.Enabled = false;             }   The above code will disable the title field in edit mode. You can add more code here to achieve more customization according to your requirement. Some of the examples are as follow:             //Adding post back event on UserField to auto populate some other dependent field             //in new mode and disable it in edit mode             if (_ControlMode != SPControlMode.Display && fieldDisplayName == "Manager")             {                 if (fieldControl.Controls[0].FindControl("UserField") != null)                 {                     PeopleEditor pplEditor = (PeopleEditor)fieldControl.Controls[0].FindControl("UserField");                     if (_ControlMode == SPControlMode.New)                         pplEditor.AutoPostBack = true;                     else                         pplEditor.Enabled = false;                 }             }               //Add JavaScript Event on Dropdown field. Don't forget to add the JavaScript function on the page.             if (_ControlMode == SPControlMode.Edit && fieldDisplayName == "Designation")             {                 DropDownList ddlCategory = (DropDownList)fieldControl.Controls[0];                 ddlCategory.Attributes.Add("onchange", string.Format("javascript:DropdownChangeEvent('{0}');return false;", ddlCategory.ClientID));             }    Following are the screenshots of my Custom ListForm WebPart. Let’s play a game, check out your OOB List forms of SharePoint, compare with these screens and find out differences.   DispForm.aspx:   EditForm.aspx:   NewForm.aspx:   Enjoy the SharePoint Soup!!! ­­­­­­­­­­­­­­­­­­­­

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  • Composite-like pattern and SRP violation

    - by jimmy_keen
    Recently I've noticed myself implementing pattern similar to the one described below. Starting with interface: public interface IUserProvider { User GetUser(UserData data); } GetUser method's pure job is to somehow return user (that would be an operation speaking in composite terms). There might be many implementations of IUserProvider, which all do the same thing - return user basing on input data. It doesn't really matter, as they are only leaves in composite terms and that's fairly simple. Now, my leaves are used by one own them all composite class, which at the moment follows this implementation: public interface IUserProviderComposite : IUserProvider { void RegisterProvider(Predicate<UserData> predicate, IUserProvider provider); } public class UserProviderComposite : IUserProviderComposite { public User GetUser(SomeUserData data) ... public void RegisterProvider(Predicate<UserData> predicate, IUserProvider provider) ... } Idea behind UserProviderComposite is simple. You register providers, and this class acts as a reusable entry-point. When calling GetUser, it will use whatever registered provider matches predicate for requested user data (if that helps, it stores key-value map of predicates and providers internally). Now, what confuses me is whether RegisterProvider method (brings to mind composite's add operation) should be a part of that class. It kind of expands its responsibilities from providing user to also managing providers collection. As far as my understanding goes, this violates Single Responsibility Principle... or am I wrong here? I thought about extracting register part into separate entity and inject it to the composite. As long as it looks decent on paper (in terms of SRP), it feels bit awkward because: I would be essentially injecting Dictionary (or other key-value map) ...or silly wrapper around it, doing nothing more than adding entires This won't be following composite anymore (as add won't be part of composite) What exactly is the presented pattern called? Composite felt natural to compare it with, but I realize it's not exactly the one however nothing else rings any bells. Which approach would you take - stick with SRP or stick with "composite"/pattern? Or is the design here flawed and given the problem this can be done in a better way?

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  • why do we need to put private members in headers

    - by Simon
    Private variables are a way to hide complexity and implementation details to the user of a class. This is a rather nice feature. But I do not understand why in c++ we need to put them in the header of a class. I see some annoying downsides to this: it clutters the header from the user it force recompilation of all client libraries whenever the internals are modified Is there a conceptual reason behind this requirement? Is it only to ease the work of the compiler?

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  • Removing Menu Items from Window Tabs

    - by Geertjan
    So you're working on your NetBeans Platform application and you notice that when you right-click on tabs in the predefined windows, e.g., the Projects window, you see a long list of popup menus. For whatever the reason is, you decide you don't want those popup menus. You right-click the application and go to the Branding dialog. There you uncheck the checkboxes that are unchecked below: As you can see above, you've removed three features, all of them related to closing the windows in your application. Therefore, "Close" and "Close Group" are now gone from the list of popup menus: But that's not enough. You also don't want the popup menus that relate to maximizing and minimizing the predefined windows, so you uncheck those checkboxes that relate to that: And, hey, now they're gone too: Next, you decide to remove the feature for floating, i.e., undocking the windows from the main window: And now they're gone too: However, even when you uncheck all the remaining checkboxes, as shown here... You're still left with those last few pesky popup menu items that just will not go away no matter what you do: The reason for the above? Those actions are hardcoded into the action list, which is a bug. Until it is fixed, here's a handy workaround: Set an implementation dependency on "Core - Windows" (core.window). That is, set a dependency and then specify that it is an implementation dependency, i.e., that you'll be using an internal class, not one of the official APIs. In one of your existing modules, or in a new one, make sure you have (in addition to the above) a dependency on Lookup API and Window System API. And then, add the class below to the module: import javax.swing.Action; import org.netbeans.core.windows.actions.ActionsFactory; import org.openide.util.lookup.ServiceProvider; import org.openide.windows.Mode; import org.openide.windows.TopComponent; @ServiceProvider(service = ActionsFactory.class) public class EmptyActionsFactory extends ActionsFactory { @Override public Action[] createPopupActions(TopComponent tc, Action[] actions) { return new Action[]{}; } @Override public Action[] createPopupActions(Mode mode, Action[] actions) { return new Action[]{}; } } Hurray. Farewell to superfluous popup menu items on your window tabs. In the screenshot below, the tab of the Projects window is being right-clicked and no popup menu items are shown, which is true for all the other windows, those that are predefined as well as those that you add afterwards:

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  • Business layer access to the data layer

    - by rerun
    I have a Business layer (BL) and a Data layer (DL). I have an object o with a child objects collection of Type C. I would like to provide a semantics like the following o.Children.Add("info"). In the BL I would like to have a static CLASS that all of business layer classes uses to get a reference to the current datalayer instance. Is there any issue with that or must I use the factory pattern to limit creation to A class in the BL that knows the DL instance.

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  • When to use Constants vs. Config Files to maintain Configuration

    - by CoffeeAddict
    I often fight with myself on whether to put certain keys in my web.config or in a Constants.cs class or something like this. For example if I wanted to store application specific keys for whatever the case may be..I could store it and grab it from my web config via custom keys or consume it by referencing a constant in my constants class. When would you want to use Constants over config keys? This question really applies to any language I think.

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  • Design: classes with same implementation but different method names

    - by Dror Helper
    I have multiple classes that have similar implementation for different named methods: class MyClassX { public int MyClassXIntMethod(){} public string MyClassXStringMethod(){} } class MyClassY { public int MyClassYIntMethod(){} public string MyClassYStringMethod(){} } the methods inside the classes have similar implementation but because the method's names are different (due to 3rd party constraints) i cannot use inheritance. I'm looking for an elegant solution that would be better than implementing the same functionality over and over again.

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  • Best Practices for serializing/persisting String Object Dictionary entities

    - by Mark Heath
    I'm noticing a trend towards using a dictionary of string to object (or sometimes string to string), instead of strongly typed objects. For example, the new Katana project makes heavy use of IDictionary<string,object>. This approach avoids the need to continually update your entity classes/DTOs and the database tables that persist them with new properties. It also avoids the need to create new derived entity types to support new types of entity, since the Dictionary is flexible enough to store any arbitrary properties. Here's a contrived example: class StorageDevice { public int Id { get; set; } public string Name { get; set; } } class NetworkShare : StorageDevice { public string Path { get; set; } public string LoginName { get; set; } public string Password { get; set; } } class CloudStorage : StorageDevice { public string ServerUri { get; set } public string ContainerName { get; set; } public int PortNumber { get; set; } public Guid ApiKey { get; set; } } versus: class StorageDevice { public IDictionary<string, object> Properties { get; set; } } Basically I'm on the lookout for any talks, books or articles on this approach, so I can pick up on any best practices / difficulties to avoid. Here's my main questions: Does this approach have a name? (only thing I've heard used so far is "self-describing objects") What are the best practices for persisting these dictionaries into a relational database? Especially the challenges of deserializing them successfully with strongly typed languages like C#. Does it change anything if some of the objects in the dictionary are themselves lists of strongly typed entities? Should a second dictionary be used if you want to temporarily store objects that are not to be persisted/serialized across a network, or should you use some kind of namespacing on the keys to indicate this?

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  • Car animations in Frogger on Javascript

    - by Mijoro Nicolas Rasoanaivo
    I have to finish a Frogger game in Javascript for my engineering school degree, but I don't know how to animate the cars. Right now I tried to manipulate the CSS, the DOM, I wrote a script with a setTimeout(), but none of them works.Can I have some help please? Here's my code and my CSS: <html> <head> <title>Image d&eacute;filante</title> <link rel="stylesheet" type="text/css" href="map_style.css"/> </head> <body onload="start()"> <canvas id="jeu" width="800" height="450"> </canvas> <img id="voiture" class="voiture" src="car.png" onload="startTimerCar()"> <img id="voiture2" class="voiture" src="car.png" onload="startTimerCar()"> <img id="voiture3" class="voiture" src="car.png" onload="startTimerCar()"> <img id="bigrig" class="bigrig" src="bigrig.png" onload="startTimerBigrig()"> <img id="bigrig2" class="bigrig" src="bigrig.png" onload="startTimerBigrig()"> <img id="bigrig3" class="bigrig" src="bigrig.png" onload="startTimerBigrig()"> <img id="hotrod" src="hotrod.png" onload="startTimerHotrod()"> <img id="hotrod2" src="hotrod.png" onload="startTimerHotrod()"> <img id="turtle" src="turtles_diving.png" onload="startTimerTurtle()"> <img id="turtle2" src="turtles_diving.png" onload="startTimerTurtle()"> <img id="turtle3" src="turtles_diving.png" onload="startTimerTurtle()"> <img id="small" src="log_small.png" onload="startTimerSmall()"> <img id="small2" src="log_small.png" onload="startTimerSmall()"> <img id="small3" src="log_small.png" onload="startTimerSmall()"> <img id="small4" src="log_small.png" onload="startTimerSmall()"> <img id="med" src="log_medium.png" onload="startTimerMedium()"> <img id="med2" src="log_medium.png" onload="startTimerMedium()"> <img id="med3" src="log_medium.png" onload="startTimerMedium()"> <script type="text/javascript"> var X = 1; var timer; function start(){ setInterval(init,10); document.onkeydown = move; var canvas = document.getElementById('jeu'); var context = canvas.getContext('2d'); var frog = document.getElementById('frog'); var posX_frog = 415; var posY_frog = 400; var voiture = [document.getElementById('voiture'),document.getElementById('voiture2'),document.getElementById('voiture3')]; var bigrig = [document.getElementById('bigrig'),document.getElementById('bigrig2'),document.getElementById('bigrig3')]; var hotrod = [document.getElementById('hotrod'),document.getElementById('hotrod2')]; var turtle = [document.getElementById('turtle'),document.getElementById('turtle2'),document.getElementById('turtle3')]; var small = [document.getElementById('small'),document.getElementById('small2'),document.getElementById('small3'),document.getElementById('small4')]; var med = [document.getElementById('med'),document.getElementById('med2'),document.getElementById('med3')]; function init() { context.fillStyle = "#AEEE00"; context.fillRect(0,0,800,50); context.fillRect(0,200,800,50); context.fillRect(0,400,800,50); context.fillStyle = "#046380"; context.fillRect(0,50,800,150); context.fillStyle = "#000000"; context.fillRect(0,250,800,150); var img= new Image(); img.src="./frog.png"; context.drawImage(img,posX_frog, posY_frog, 46, 38); } function move(event){ if (event.keyCode == 39){ if( posX_frog < 716 ){ posX_frog += 50; } } if(event.keyCode == 37){ if( posX_frog >25 ){ posX_frog -= 50; } } if (event.keyCode == 38){ if( posY_frog > 10 ){ posY_frog -= 50; } } if(event.keyCode == 40){ if( posY_frog <400 ){ posY_frog += 50; } } } } </script> </body> And my map_css: #jeu{ z-index:10; width: 800px; height: 450px; border: 2px black solid; overflow: hidden; position: relative; transition:width 2s; -moz-transition:width 2s; /* Firefox 4 */ -webkit-transition:width 2s; /* Safari and Chrome */ } #voiture{ z-index: 100; position: absolute; top: 315px; left: 48px; transition-timing-function: linear; -webkit-transition-timing-function: linear; -moz-transition-timing-function: linear; } #voiture2{ z-index: 100; position: absolute; top: 315px; left: 144px; } #voiture3{ z-index: 100; position: absolute; top: 315px; left: 240px; } #bigrig{ z-index: 100; position: absolute; top: 365px; left: 200px; } #bigrig2{ z-index: 100; position: absolute; top: 365px; left: 400px; } #bigrig3{ z-index: 100; position: absolute; top: 365px; left: 600px; } #hotrod{ z-index: 100; position: absolute; top: 265px; left: 200px; } #hotrod2{ z-index: 100; position: absolute; top: 265px; left: 500px; } #hotrod3{ z-index: 100; position: absolute; top: 265px; left: 750px; } #turtle{ z-index: 100; position: absolute; top: 175px; left: 50px; } #turtle2{ z-index: 100; position: absolute; top: 175px; left: 450px; } #turtle3{ z-index: 100; position: absolute; top: 175px; left: 250px; } #small{ z-index: 100; position: absolute; top: 125px; left: 20px; } #small2{ z-index: 100; position: absolute; top: 125px; left: 220px; } #small3{ z-index: 100; position: absolute; top: 125px; left: 420px; } #small4{ z-index: 100; position: absolute; top: 125px; left: 620px; } #med{ z-index: 100; position: absolute; top: 75px; left: 120px; } #med2{ z-index: 100; position: absolute; top: 75px; left: 320px; } #med3{ z-index: 100; position: absolute; top: 75px; left: 520px; } I had to say that I'm in the obligation to code in HTML5, CSS3, and Javascript but not jQuery, who is way more easier, I already created games in jQuery... It takes me too much time and too much code lines right here.

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