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  • Is hierarchical product backlog a good idea in TFS 2012-2013?

    - by Matías Fidemraizer
    I'd like to validate I'm not in the wrong way. My team project is using Visual Studio Scrum 2.x. Since each area/product has a lot of kind of requirements (security, user interface, HTTP/REST services...), I tried to manage this creating "parent backlogs" which are "open forever" and they contain generic requirements. Those parent backlogs have other "open forever" backlogs, and/or sprint backlogs. For example: HTTP/REST Services (forever) ___ Profiles API (forever) ________ POST profile (forever) _______________ We need a basic HTTP/REST profiles' API to register new user profiles (sprint backlog) Is it the right way of organizing the product backlog? Note: I know there're different points of view and that would be right for some and wrong for others. I'm looking for validation about if this is a possible good practice on TFS with Visual Studio Scrum.

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  • Build in better usability with UX Direct

    - by JuergenKress
    The Oracle Applications User Experience team has created a program called Oracle UX Direct to provide customers, partners, and consultants in the enterprise industry with design best-practices and tools that they can leverage to make their enterprise implementations more successful. Read the Voice of User Experience, or VoX, blog to learn more about why the program was created, and visit the UX Direct web site to find out how to introduce design thinking during the implementation stage. Create a solution that best fits the needs of users from the beginning. Read more about UX Direct on VoX. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Mix Forum Technorati Tags: UX,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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  • Need help identifing what resources (eg. In MIT OpenCourseWare) can help me prepare for a test [closed]

    - by jiewmeng
    I am entering uni soon. I can sit for a placement test to see if I elegible for exemptions. The details are http://www.comp.nus.edu.sg/undergraduates/TestScope11_12.html Or CS2100 Computer Organisation (please click title) The objective of this module is to familiarise students with the fundamentals of computing devices. Through this module students will understand the basics of data representation, and how the various parts of a computer work, separately and with each other. This allows students to understand the issues in computing devices, and how these issues affect the implementation of solutions. Topics covered include data representation systems, combinational and sequential circuit design techniques, assembly language, processor execution cycles, pipelining, memory hierarchy and input/output systems. Recommended Textbooks Digital Design: Principles and Practices [DDPP] by John F. Wakerly, Prentice-Hall. ISBN 0-13-324500-4. Computer Organizations and Design (The hardware/software interface) by David A. Patterson and John L. Hennessy. CS2105 Introduction to Computer Networks (please click title) This course aims to provide a broad introduction to computer networks and some appreciations of network application programming. It covers a range of topics including basic data communication and computer network concepts, protocols, networked computing concepts and principles, network applications development and network security. The emphasis of teaching is on the working principles and application of computer networks. As an integral part of the course, tutorials and practical assignments enforcing learning will also be given. These assignments provide an early exposure in network application programming and they should be able to complete by using personal computers and school's network facilities. Topics included: An overview of computer networks and the Internet Basic data communications Application layer Transport layer Network layer and routing Link layer and local area networks Recommended Textbook James F. Kurose & Keith W. Ross, Computer networking: A top-down approach featuring internet, Addison Wesley, 2001 I am wondering what resources eg. MIT OpenCourseWare or other universities resources are available to help he perpare for these particular modubles. I am thinking does the Networking one look like CCNA? The computer oragization. Its like electronics, assembly etc? I learnt some electronics in Poly but looking at the sample papers, uni looks very different... I have about 1 month to prepare if I want any chance of exempting from these modules :) any help?

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  • YouTube: Up & Running with Twitter Bootstrap

    - by Geertjan
    "Twitter Bootstrap is a free collection of tools for creating websites and web applications. It contains HTML and CSS-based design templates for typography, forms, buttons, navigation and other interface components, as well as optional JavaScript extensions. It is the most popular project on GitHub and has been used by NASA and MSNBC among others." (Wikipedia) Normally, when you read "getting started" instructions for Twitter Bootstrap, you're told to download various things from various sites. Then you're told to set up various folders and files, etc. What if it could be much simpler than that? Spend 7 minutes with me in this (silent) screencast and you'll see a complete development environment for developing applications with Twitter Bootstrap: Two things that could be added to the movie are the JavaScript debugger, the support for responsive design via switching between form factors in the embedded browser and Chrome with the NetBeans plugin, as well as how to convert the application to a native Android or iOS package via in-built Cordova support.

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  • GeoToolkit Demo Embedded in an Application Framework via Maven

    - by Geertjan
    As a follow on to yesterday's blog entry, here's the equivalent starter application for GeoToolkit (also known as Geotk) on the NetBeans Platform, which ends up looking like this: The above is a border.shp file I found on-line, while here's a USA states shape file rendered in the application: Note that the navigation bar is also included, though that could later be migrated into the menu bar of the NetBeans Platform.  Download the Maven based NetBeans Platform application with GeoToolkit integration here: http://java.net/projects/nb-api-samples/sources/api-samples/show/versions/7.3/tutorials/geospatial/geotoolkit/MyGeospatialSystem It was quite tricky getting this sample together, parts of it, especially the installer, which creates the database, comes from the Puzzle GIS project, while the files come from on-line locations, with the JAI-related dependencies providing problems of their own. But it's definitely a starting point and you now have the basic Maven structure needed for getting started with GeoToolkit in the context of all the services and components provided by the NetBeans Platform.  Many thanks to Johann Sorel for his patience and help. 

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  • A good course on HTML/CSS/JS/UX worth it in part time?

    - by zengr
    I am a java/ruby developer from the last 3yrs, trying my hands on JS now. I am fascinated by the awesome UI designs these days. Any app I make, the worst aspect is the UI and I suck at it. I end up copying a design and with a crappy one. I am a student in San Jose, CA, and will be working from next month on Java most probably. My questions are: Are there any good courses (in the the colleges in silicon valley) on web Design (Photoshop), html, css, JS? Is it worth it?

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  • Generation 4 Modular Data Center

    - by kaleidoscope
    Microsoft’s launched Generation 4 Modular Data Center design at the PDC 09 - The 20-foot container built on container-based model. Microsoft says the use of server-packed containers – known as Pre-Assembled Components (PACs) – will allow it to slash the cost of building its new data centers. Completely optimized for outdoor use, with a design that relies upon fresh air (”free cooling”) rather than air conditioning. Its exterior is designed to draw fresh air into the cold aisle and expel hot air from the rear of the hot aisle. More details can be found at: http://www.datacenterknowledge.com/archives/2009/11/18/microsofts-windows-azure-cloud-container/   Rituraj, J

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  • Oracle OpenWorld Update -- Highly Available WebLogic Messaging Architectures: Sharing a Customer Experience with Comcast

    - by Ruma Sanyal
    This session will describe a Comcast’s hands-on  experience using WebLogic JMS as their high-performance enterprise messaging system including high availability, and disaster recovery capabilities as Comcast is rolling out a cross-site active-active message bus. In the session, we will cover the following: Key capabilities in WebLogic JMS that enabled Comcast to design such an architecture Details of the architecture put in place Details about application design needed to make all of this successful Failover and fail back processes The results from this new architecture are higher availability, better performance, more flexibility, and reduced costs through better utilization of hardware and improved manageability. For more information about this and other WebLogic sessions, review the Oracle WebLogic Focus On document here. Details: Tuesday, Oct 2, 5-6pm, Moscone South Room 306

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  • Utility Objects Series Introduction (but mostly a bit of an update)

    - by drsql
    So, I have been away from blogging about technical stuff for a  long time,  (I haven’t blogged at all since my resolutions blog , and even my Simple Talk “commentary” blog hasn’t had an entry since December!)  Most of this has been due to finishing up my database design book , which I will blog about at least one more time after it ships next month, but now it is time to get back to it certainly in a bit more regularly. For SQL Rally, I have two sessions, a precon on Database Design,...(read more)

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  • web services, J2EE, spring, DB integration project ideas- maybe data mining related?

    - by sj88
    Hey guys, I am a graduate CS student (Data mining and machine learning) and have a good exposure to core JAVA (3 years). I have read up a bunch of stuff on Design patterns J2EE Web services( soap and rest) spring and hibernate Java Concurrency - advanced features like Task and Executors. I would now like to do a project combining this stuff (over my free time of corse) to get a better understanding of these things and to kind of make an end to end software (to learn the best design principles etc + svn, maven). Any good project ideas would be really appreciated. I just wanna build this stuff to learn so I dont really mind re-inventing the wheel. Also, anything related to data mining would be an added bonus (fits with my research) but absolutly not necesary (since this project is more to learn to do large scale software developement)

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  • Code to simulate a users actions, such as logging in

    - by Gortron
    I've recently begun working on a PHP application, replacing another developer. I believed the application was using an API to communicate with a remote service but when I looked through the code I found that it was using a set of functions to actually log in, fill out forms and submit them as a user might do in a browser. My intention is to replace this code, to use the services API instead. I've considered leaving the code as is and not replace it. It makes me wonder though is this a common practice in the software industry? To have a programme simulate a users actions in a browser to perform a set of actions? It feels to me that this is clever but poor programming, Have any other developers seen this?

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  • How to Implement Project Type "Copy", "Move", "Rename", and "Delete"

    - by Geertjan
    You've followed the NetBeans Project Type Tutorial and now you'd like to let the user copy, move, rename, and delete the projects conforming to your project type. When they right-click a project, they should see the relevant menu items and those menu items should provide dialogs for user interaction, followed by event handling code to deal with the current operation. Right now, at the end of the tutorial, the "Copy" and "Delete" menu items are present but disabled, while the "Move" and "Rename" menu items are absent: The NetBeans Project API provides a built-in mechanism out of the box that you can leverage for project-level "Copy", "Move", "Rename", and "Delete" actions. All the functionality is there for you to use, while all that you need to do is a bit of enablement and configuration, which is described below. To get started, read the following from the NetBeans Project API: http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-projectapi/org/netbeans/spi/project/ActionProvider.html http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-projectapi/org/netbeans/spi/project/CopyOperationImplementation.html http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-projectapi/org/netbeans/spi/project/MoveOrRenameOperationImplementation.html http://bits.netbeans.org/dev/javadoc/org-netbeans-modules-projectapi/org/netbeans/spi/project/DeleteOperationImplementation.html Now, let's do some work. For each of the menu items we're interested in, we need to do the following: Provide enablement and invocation handling in an ActionProvider implementation. Provide appropriate OperationImplementation classes. Add the new classes to the Project Lookup. Make the Actions visible on the Project Node. Run the application and verify the Actions work as you'd like. Here we go: Create an ActionProvider. Here you specify the Actions that should be supported, the conditions under which they should be enabled, and what should happen when they're invoked, using lots of default code that lets you reuse the functionality provided by the NetBeans Project API: class CustomerActionProvider implements ActionProvider { @Override public String[] getSupportedActions() { return new String[]{ ActionProvider.COMMAND_RENAME, ActionProvider.COMMAND_MOVE, ActionProvider.COMMAND_COPY, ActionProvider.COMMAND_DELETE }; } @Override public void invokeAction(String string, Lookup lkp) throws IllegalArgumentException { if (string.equalsIgnoreCase(ActionProvider.COMMAND_RENAME)) { DefaultProjectOperations.performDefaultRenameOperation( CustomerProject.this, ""); } if (string.equalsIgnoreCase(ActionProvider.COMMAND_MOVE)) { DefaultProjectOperations.performDefaultMoveOperation( CustomerProject.this); } if (string.equalsIgnoreCase(ActionProvider.COMMAND_COPY)) { DefaultProjectOperations.performDefaultCopyOperation( CustomerProject.this); } if (string.equalsIgnoreCase(ActionProvider.COMMAND_DELETE)) { DefaultProjectOperations.performDefaultDeleteOperation( CustomerProject.this); } } @Override public boolean isActionEnabled(String command, Lookup lookup) throws IllegalArgumentException { if ((command.equals(ActionProvider.COMMAND_RENAME))) { return true; } else if ((command.equals(ActionProvider.COMMAND_MOVE))) { return true; } else if ((command.equals(ActionProvider.COMMAND_COPY))) { return true; } else if ((command.equals(ActionProvider.COMMAND_DELETE))) { return true; } return false; } } Importantly, to round off this step, add "new CustomerActionProvider()" to the "getLookup" method of the project. If you were to run the application right now, all the Actions we're interested in would be enabled (if they are visible, as described in step 4 below) but when you invoke any of them you'd get an error message because each of the DefaultProjectOperations above looks in the Lookup of the Project for the presence of an implementation of a class for handling the operation. That's what we're going to do in the next step. Provide Implementations of Project Operations. For each of our operations, the NetBeans Project API lets you implement classes to handle the operation. The dialogs for interacting with the project are provided by the NetBeans project system, but what happens with the folders and files during the operation can be influenced via the operations. Below are the simplest possible implementations, i.e., here we assume we want nothing special to happen. Each of the below needs to be in the Lookup of the Project in order for the operation invocation to succeed. private final class CustomerProjectMoveOrRenameOperation implements MoveOrRenameOperationImplementation { @Override public List<FileObject> getMetadataFiles() { return new ArrayList<FileObject>(); } @Override public List<FileObject> getDataFiles() { return new ArrayList<FileObject>(); } @Override public void notifyRenaming() throws IOException { } @Override public void notifyRenamed(String nueName) throws IOException { } @Override public void notifyMoving() throws IOException { } @Override public void notifyMoved(Project original, File originalPath, String nueName) throws IOException { } } private final class CustomerProjectCopyOperation implements CopyOperationImplementation { @Override public List<FileObject> getMetadataFiles() { return new ArrayList<FileObject>(); } @Override public List<FileObject> getDataFiles() { return new ArrayList<FileObject>(); } @Override public void notifyCopying() throws IOException { } @Override public void notifyCopied(Project prjct, File file, String string) throws IOException { } } private final class CustomerProjectDeleteOperation implements DeleteOperationImplementation { @Override public List<FileObject> getMetadataFiles() { return new ArrayList<FileObject>(); } @Override public List<FileObject> getDataFiles() { return new ArrayList<FileObject>(); } @Override public void notifyDeleting() throws IOException { } @Override public void notifyDeleted() throws IOException { } } Also make sure to put the above methods into the Project Lookup. Check the Lookup of the Project. The "getLookup()" method of the project should now include the classes you created above, as shown in bold below: @Override public Lookup getLookup() { if (lkp == null) { lkp = Lookups.fixed(new Object[]{ this, new Info(), new CustomerProjectLogicalView(this), new CustomerCustomizerProvider(this), new CustomerActionProvider(), new CustomerProjectMoveOrRenameOperation(), new CustomerProjectCopyOperation(), new CustomerProjectDeleteOperation(), new ReportsSubprojectProvider(this), }); } return lkp; } Make Actions Visible on the Project Node. The NetBeans Project API gives you a number of CommonProjectActions, including for the actions we're dealing with. Make sure the items in bold below are in the "getActions" method of the project node: @Override public Action[] getActions(boolean arg0) { return new Action[]{ CommonProjectActions.newFileAction(), CommonProjectActions.copyProjectAction(), CommonProjectActions.moveProjectAction(), CommonProjectActions.renameProjectAction(), CommonProjectActions.deleteProjectAction(), CommonProjectActions.customizeProjectAction(), CommonProjectActions.closeProjectAction() }; } Run the Application. When you run the application, you should see this: Let's now try out the various actions: Copy. When you invoke the Copy action, you'll see the dialog below. Provide a new project name and location and then the copy action is performed when the Copy button is clicked below: The message you see above, in red, might not be relevant to your project type. When you right-click the application and choose Branding, you can find the string in the Resource Bundles tab, as shown below: However, note that the message will be shown in red, no matter what the text is, hence you can really only put something like a warning message there. If you have no text at all, it will also look odd.If the project has subprojects, the copy operation will not automatically copy the subprojects. Take a look here and here for similar more complex scenarios. Move. When you invoke the Move action, the dialog below is shown: Rename. The Rename Project dialog below is shown when you invoke the Rename action: I tried it and both the display name and the folder on disk are changed. Delete. When you invoke the Delete action, you'll see this dialog: The checkbox is not checkable, in the default scenario, and when the dialog above is confirmed, the project is simply closed, i.e., the node hierarchy is removed from the application. However, if you truly want to let the user delete the project on disk, pass the Project to the DeleteOperationImplementation and then add the children of the Project you want to delete to the getDataFiles method: private final class CustomerProjectDeleteOperation implements DeleteOperationImplementation { private final CustomerProject project; private CustomerProjectDeleteOperation(CustomerProject project) { this.project = project; } @Override public List<FileObject> getDataFiles() { List<FileObject> files = new ArrayList<FileObject>(); FileObject[] projectChildren = project.getProjectDirectory().getChildren(); for (FileObject fileObject : projectChildren) { addFile(project.getProjectDirectory(), fileObject.getNameExt(), files); } return files; } private void addFile(FileObject projectDirectory, String fileName, List<FileObject> result) { FileObject file = projectDirectory.getFileObject(fileName); if (file != null) { result.add(file); } } @Override public List<FileObject> getMetadataFiles() { return new ArrayList<FileObject>(); } @Override public void notifyDeleting() throws IOException { } @Override public void notifyDeleted() throws IOException { } } Now the user will be able to check the checkbox, causing the method above to be called in the DeleteOperationImplementation: Hope this answers some questions or at least gets the discussion started. Before asking questions about this topic, please take the steps above and only then attempt to apply them to your own scenario. Useful implementations to look at: http://kickjava.com/src/org/netbeans/modules/j2ee/clientproject/AppClientProjectOperations.java.htm https://kenai.com/projects/nbandroid/sources/mercurial/content/project/src/org/netbeans/modules/android/project/AndroidProjectOperations.java

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  • why write-enable ring

    - by SpashHit
    Here's an "interview question" that while ostensibly about hardware really does inform a software design principal as well. Computers used to (still do I guess, somewhere) use magnetic tape reels to store data. There was a plastic accessory you could attach to a tape reel called a "write-enable ring". If the tape had such a ring, the tape drive allowed writing to the tape... if not, it only allowed read access. Why was the choice to design the system in this way? Why not have a "write protect ring" instead, with the opposite effect?

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  • What HTML and CSS markup is best for SEO for a list of questions (like on Stack Exchange sites)

    - by Oleg9
    On the StackOverflow a question block (in the q-list on the index page and so on) represented by the following html code: <div class="question-summary narrow tagged-interesting" id="question-summary-19832613"> <div onclick="window.location.href='/questions/19832613/how-to-display-only-transit-routesfor-trains-in-google-maps-api'" class="cp"> <div class="votes"> <div class="mini-counts">0</div> <div>votes</div> </div> <div class="status unanswered"> <div class="mini-counts">0</div> <div>answers</div> </div> <div class="views"> <div class="mini-counts">3</div> <div>views</div> </div> </div> <div class="summary"> <h3>...</h3> <div class="tags t-javascript t-google-maps t-google t-google-maps-api-3"> </div> <div class="started"> <a href="/questions/19832613/how-to-display-only-transit-routesfor-trains-in-google-maps-api" class="started-link"><span title="2013-11-07 09:52:29Z" class="relativetime">1 min ago</span></a> <a href="/users/1309392/shirish">Shirish</a> <span class="reputation-score" title="reputation score " dir="ltr">189</span> </div> </div> </div> It uses float positioning. My questions is: Would use of css styled tables be a better choice? (It's a table, isn't it?) Or it just depends on what are you prefer to use and doesn't affect the technical side (search engines or something)? The background information (such as number of views, votes etc.) comes first in the code. And I know that search engines have a limit at viewing each page. So would it better to place div's depending on their importance and then markup them on the page using css methods (like negative margins and absolute positioning)? Or it isn't so important in this instance?

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  • Free eBook: 45 Database Performance Tips for Developers

    As a developer, if you need to go into the database and write queries, design tables, or determine the configuration of your SQL Server Systems, these tips should help make sure you're not unnecessarily sacrificing database performance. This eBook has 45 easy tips to improve the performance of your indexes and T-SQL queries, and hunt down problems within ORM tools and database design. Save 45% on our top SQL Server database administration tools. Together they make up the SQL DBA Bundle, which supports your core tasks and helps your day run smoothly. Download a free trial now.

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  • Even More Steroids for JEditorPane

    - by Geertjan
    Got some help from Ralph today and now the JEditorPane is as I want it, e.g., code folds are now supported once you click in the JEditorPane, though there are still some side effects, since this is not how anyone anticipated NetBeans editor APIs being used. But, so far, the side effects (e.g., now the hyperlinks work, but they open a new JavaScript file when you click on one of them, instead of jumping within the JEditorPane itself) are not so terrible. Error checking is also done now, which wasn't there before, i.e., red underlines and error annotations in the right margin. And maybe it's my imagination, but the editor feels a lot snappier, e.g., in code completion, than before. I've checked in the changes, they're all in this file: http://java.net/projects/nb-api-samples/sources/api-samples/content/versions/7.3/misc/CMSBackOffice2/CMSBackOffice2-editor/src/main/java/com/mycompany/cmsbackoffice2editor/GeneralTab.java

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  • exact point oh a rotating sphere

    - by nkint
    I have a sphere that represents the heart textured with real pictures. It's rotating about the x axis, and when user click down it has to show me the exact place he clicked on. For example if he clicked on Singapore and the system should be able to: understand that user clicked on the sphere (OK, I'll do it with unProject) understand where user clicked on the sphere (ray-sphere collision?) and take into account the rotation transform sphere-coordinate to some coordinate system good for some web-api service ask to api (OK, this is the simpler thing for me ;-) some advice?

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  • What do you look for when debugging deadlocks?

    - by Michael K
    Recently I've been working on projects that heavily use threading. I think that I'm OK at designing them; use stateless design as much as possible, lock access to all resources that more than one thread needs, etc. My experience in functional programming has helped that immensely. However, when reading other people's thread code, I get confused. I am debugging a deadlock right now, and since the coding style and design are different from my personal style, I am having a difficult time seeing potential deadlock conditions. What do you look for when debugging deadlocks?

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  • Constraints while designing the Java generics

    - by Andrea
    Java generics look quite different from those available in Scala, although both were designed by Martin Odersky. From my point of view, the design of generics in Java is worse, for instance: there is no possibility to specify variance one can get around the previous limitation by using wildcards, but this means the burden of specifying variance goes on the caller instead of the library designer one cannot use a type constructor in generics What were the constraints in Java that forced Odersky to design this mechanism for generics instead of the more flexible one he devised for Scala? Was he just savvier a few years later or there were actual limitations due to Java?

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  • The ETL from Hell - Diagnosing Batch System Performance Issues

    Too often, the batch systems that underlie a lot of database processing just grow without conscious design. When runs start to extend beyond their allotted time, and tuning no longer solves the problem, it is often discovered that batches are run in series, with draconian error handling. It is time to impose some rational design, and Nigel is a seasoned healer of batch processes. The seven tools in the SQL DBA Bundle support your core SQL Server database administration tasks.Make backups a breeze! Enjoy trouble-free troubleshooting! Make the most of monitoring! Download a free trial now.

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  • Consultant in a firm that doesn't understand the tech!

    - by techsjs2012
    I got the job as a Consultant in a firm that has 3 other programmers. My job is to rewrite all the old system in Java, Spring etc but the staff programmers only know perl and the manager does not know any programming. I am trying to get them to understand that I have 6 projects to rewrite here but no one has design docs or spec. the staff programmers never had to write any documents. Plus I cant get the manager to understand the new java tech stuff.. he keeps asking some of the staff for views on things but the staff don't know it or understand it. Where do I go from here to make the manager understand that the staff programmers or someone has to write a design document so I know what to build. or if I have to write the documents how do I get the information?

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  • Collaborative Whiteboard using WebSocket in GlassFish 4 - Text/JSON and Binary/ArrayBuffer Data Transfer (TOTD #189)

    - by arungupta
    This blog has published a few blogs on using JSR 356 Reference Implementation (Tyrus) as its integrated in GlassFish 4 promoted builds. TOTD #183: Getting Started with WebSocket in GlassFish TOTD #184: Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark TOTD #185: Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket TOTD #186: Custom Text and Binary Payloads using WebSocket One of the typical usecase for WebSocket is online collaborative games. This Tip Of The Day (TOTD) explains a sample that can be used to build such games easily. The application is a collaborative whiteboard where different shapes can be drawn in multiple colors. The shapes drawn on one browser are automatically drawn on all other peer browsers that are connected to the same endpoint. The shape, color, and coordinates of the image are transfered using a JSON structure. A browser may opt-out of sharing the figures. Alternatively any browser can send a snapshot of their existing whiteboard to all other browsers. Take a look at this video to understand how the application work and the underlying code. The complete sample code can be downloaded here. The code behind the application is also explained below. The web page (index.jsp) has a HTML5 Canvas as shown: <canvas id="myCanvas" width="150" height="150" style="border:1px solid #000000;"></canvas> And some radio buttons to choose the color and shape. By default, the shape, color, and coordinates of any figure drawn on the canvas are put in a JSON structure and sent as a message to the WebSocket endpoint. The JSON structure looks like: { "shape": "square", "color": "#FF0000", "coords": { "x": 31.59999942779541, "y": 49.91999053955078 }} The endpoint definition looks like: @WebSocketEndpoint(value = "websocket",encoders = {FigureDecoderEncoder.class},decoders = {FigureDecoderEncoder.class})public class Whiteboard { As you can see, the endpoint has decoder and encoder registered that decodes JSON to a Figure (a POJO class) and vice versa respectively. The decode method looks like: public Figure decode(String string) throws DecodeException { try { JSONObject jsonObject = new JSONObject(string); return new Figure(jsonObject); } catch (JSONException ex) { throw new DecodeException("Error parsing JSON", ex.getMessage(), ex.fillInStackTrace()); }} And the encode method looks like: public String encode(Figure figure) throws EncodeException { return figure.getJson().toString();} FigureDecoderEncoder implements both decoder and encoder functionality but thats purely for convenience. But the recommended design pattern is to keep them in separate classes. In certain cases, you may even need only one of them. On the client-side, the Canvas is initialized as: var canvas = document.getElementById("myCanvas");var context = canvas.getContext("2d");canvas.addEventListener("click", defineImage, false); The defineImage method constructs the JSON structure as shown above and sends it to the endpoint using websocket.send(). An instant snapshot of the canvas is sent using binary transfer with WebSocket. The WebSocket is initialized as: var wsUri = "ws://localhost:8080/whiteboard/websocket";var websocket = new WebSocket(wsUri);websocket.binaryType = "arraybuffer"; The important part is to set the binaryType property of WebSocket to arraybuffer. This ensures that any binary transfers using WebSocket are done using ArrayBuffer as the default type seem to be blob. The actual binary data transfer is done using the following: var image = context.getImageData(0, 0, canvas.width, canvas.height);var buffer = new ArrayBuffer(image.data.length);var bytes = new Uint8Array(buffer);for (var i=0; i<bytes.length; i++) { bytes[i] = image.data[i];}websocket.send(bytes); This comprehensive sample shows the following features of JSR 356 API: Annotation-driven endpoints Send/receive text and binary payload in WebSocket Encoders/decoders for custom text payload In addition, it also shows how images can be captured and drawn using HTML5 Canvas in a JSP. How could this be turned in to an online game ? Imagine drawing a Tic-tac-toe board on the canvas with two players playing and others watching. Then you can build access rights and controls within the application itself. Instead of sending a snapshot of the canvas on demand, a new peer joining the game could be automatically transferred the current state as well. Do you want to build this game ? I built a similar game a few years ago. Do somebody want to rewrite the game using WebSocket APIs ? :-) Many thanks to Jitu and Akshay for helping through the WebSocket internals! Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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  • Generating Wrappers for REST APIs

    - by Kyle
    Would it be feasible to generate wrappers for REST APIs? An earlier question asked about machine readable descriptions of RESTful services addressed how we could write (and then read) API specifications in a standardized way which would lend itself well to generated wrappers. Could a first pass parser generate a decent wrapper that human intervention could fix up? Perhaps the first pass wouldn't be consistent, but would remove a lot of the grunt work and make it easy to flesh out the rest of the API and types. What would need to be considered? What's stopping people from doing this? Has it already been done and my google fu is weak for the day?

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