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  • What's My Problem? What's Your Problem?

    - by Jacek Ziabicki
    Software installers are not made for building demo environments. I can say this much after 12 years (on and off) of supporting my fellow sales consultants with environments for software demonstrations. When we release software, we include installation programs and procedures that are designed for use by our clients – to build a production environment and a limited number of testing, training and development environments. Different Objectives Your priorities when building an environment for client use vs. building a demo environment are very different. In a production environment, security, stability, and performance concerns are paramount. These environments are built on a specific server and rarely, if ever, moved to a different server or different network address. There is typically just one application running on a particular server (physical or virtual). Once built, the environment will be used for months or years at a time. Because of security considerations, the installation program wants to make these environments very specific to the organization using the software and the use case, encoding a fully qualified name of the server, or even the IP address on the network, in the configuration. So you either go through the installation procedure for each environment, or learn how to clone and reconfigure the software as a separate instance to build all your non-production environments. This may not matter much if the installation is as simple as clicking on the Setup program. But for enterprise applications, you have a number of configuration settings that you need to get just right – so whether you are installing from scratch or reconfiguring an existing installation, this requires both time and expertise in the particular piece of software. If you need a setup of several applications that are integrated to talk to one another, it is a whole new level of complexity. Now you need the expertise in all of the applications involved (plus the supporting technology products), and in addition to making each application work, you also have to configure the integration endpoints. Each application needs the URLs and credentials to call the integration layer, and the integration must be able to call each application. Then you have to make sure that each app has the right data so a business process initiated in one application can continue in the next. And, you will need to check that each application has the correct version and patch level for the integration to work. When building demo environments, your #1 concern is agility. If you can get away with a small number of long-running environments, you are lucky. More likely, you may get a request for a dedicated environment for a demonstration that is two weeks away: how quickly can you make this available so we still have the time to build the client-specific data? We are running a hands-on workshop next month, and we’ll need 15 instances of application X environment so each student can have a separate server for the exercises. We cannot connect to our data center from the client site, the client’s security policy won’t allow our VPN to go through – so we need a portable environment that we can bring with us. Our consultants need to be able to work at the hotel, airport, and the airplane, so we really want an environment that can run on a laptop. The client will need two playpen environments running in the cloud, accessible from their network, for a series of workshops that start two weeks from now. We have seen all of these scenarios and more. Here you would be much better served by a generic installation that would be easy to clone. Welcome to the Wonder Machine The reason I started this blog is to share a particular design of a demo environment, a special way to install software, that can address the above requirements, even for integrated setups. This design was created by a team at Oracle Utilities Global Business Unit, and we are using this setup for most of our demo environments. In a bout of modesty we called it the Wonder Machine. Over the next few posts – think of it as a novel in parts – I will tell you about the big idea, how it was implemented and what you can do with it. After we have laid down the groundwork, I would like to share some tips and tricks for users of our Wonder Machine implementation, as well as things I am learning about building portable, cloneable environments. The Wonder Machine is by no means a closed specification, it is under active development! I am hoping this blog will be of interest to two groups of readers – the users of the Wonder Machine we have built at Oracle Utilities, who want to get the most out of their demo environments and be able to reconfigure it to their needs – and to people who need to build environments for demonstration, testing, training, development and would like to make them cloneable and portable to maximize the reuse of their effort. Surely we are not the only ones facing this problem? If you can think of a better way to solve it, or if you can help us improve on our concept, I will appreciate your comments!

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  • Migrating Virtual Iron guest to Oracle VM 3.x

    - by scoter
    As stated on the official site, Oracle in 2009, acquired a provider of server virtualization management software named Virtual Iron; you can find all the acquisition details at this link. Into the FAQ on the official site you can also view that, for the future, Oracle plans to fully integrate Virtual Iron technology into Oracle VM products, and any enhancements will be delivered as a part of the combined solution; this is what is going on with Oracle VM 3.x. So, customers started asking us to migrate Virtual Iron guests to Oracle VM. IMPORTANT: This procedure needs a dedicated OVM-Server with no-guests running on top; be careful while execute this procedure on production environments. In these little steps you will find how-to migrate, as fast as possible, your guests between VI ( Virtual Iron ) and Oracle VM; keep in mind that OracleVM has a built-in P2V utility ( Official Documentation )  that you can use to migrate guests between VI and Oracle VM. Concepts: VI repositories.  On VI we have the same "repository" concept as in Oracle VM; the difference between these two products is that VI use a raw-lun as repository ( instead of using ocfs2 and its capabilities, like ref-links ). The VI "raw-lun" repository, with a pure operating-system perspective, may be presented as in this picture: Infact on this "raw-lun" VI create an LVM2 volume-group. The VI "raw-lun" repository, with an hypervisor perspective, may be presented as in this picture: So, the relationships are: LVM2-Volume-Group <-> VI Repository LVM2-Logical-Volume <-> VI guest virtual-disk The first step is to present the VI repository ( raw-lun ) to your dedicated OVM-Server. Prepare dedicated OVM-Server On the OVM-Server ( OVS ) you need to discover new lun and, after that, discover volume-group and logical-volumes containted in VI repository; due to default OVS configuration you need to edit lvm2 configuration file: /etc/lvm/lvm.conf     # By default for OVS we restrict every block device:     # filter = [ "r/.*/" ] and comment the line starting with "filter" as above. Now you have to discover the raw-lun presented and, next, activate volume-group and logical-volumes: #!/bin/bash for HOST in `ls /sys/class/scsi_host`;do echo '- - -' > /sys/class/scsi_host/$HOST/scan; done CPATH=`pwd` cd /dev for DEVICE in `ls sd[a-z] sd?[a-z]`;do echo '1' > /sys/block/$DEVICE/device/rescan; done cd $CPATH cd /dev/mapper for PARTITION in `ls *[a-z] *?[a-z]`;do partprobe /dev/mapper/$PARTITION; done cd $CPATH vgchange -a yAfter that you will see a new device:[root@ovs01 ~]# cd /dev/6000F4B00000000000210135bef64994[root@ovs01 6000F4B00000000000210135bef64994]# ls -l 6000F4B0000000000061013* lrwxrwxrwx 1 root root 77 Oct 29 10:50 6000F4B00000000000610135c3a0b8cb -> /dev/mapper/6000F4B00000000000210135bef64994-6000F4B00000000000610135c3a0b8cb By your OVM-Manager create a guest server with the same definition as on VI:same core number as VI source guestsame memory as VI source guestsame number of disks as VI source guest ( you can create OVS virtual disk with a small size of 1GB because the "clone" will, eventually, extend the size of your new virtual disks )Summarizing:source-virtual-disk path ( VI ):/dev/mapper/6000F4B00000000000210135bef64994-6000F4B00000000000610135c3a0b8cbdest-virtual-disk path ( OVS ):/OVS/Repositories/0004fb00000300006cfeb81c12f12f00/VirtualDisks/0004fb000012000055e0fc4c5c8a35ee.img ** ** = to identify your virtual disk you have verify its name under the "vm.cfg" file of your new guest.Clone VI virtual-disk to OVS virtual-diskdd if=/dev/mapper/6000F4B00000000000210135bef64994-6000F4B00000000000610135c3a0b8cb of=/OVS/Repositories/0004fb00000300006cfeb81c12f12f00/VirtualDisks/0004fb000012000055e0fc4c5c8a35ee.img Clean unsupported parameters and changes on OVS.1. Restore original /etc/lvm/lvm.conf    # By default for OVS we restrict every block device:     filter = [ "r/.*/" ]    and uncomment the line starting with "filter" as above.2. Force-stop lvm2-monitor service  # service lvm2-monitor force-stop 3. Restore original /etc/lvm directories ( archive, backup and cache )  # cd /etc/lvm  # rm -fr archive backup cache; mkdir archive backup cache4. Reboot OVSRefresh OVS repository and start your guest.By OracleVM Manager refresh your repository:By OracleVM Manager start your "migrated" guest: Comments and corrections are welcome.  Simon COTER 

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  • High Availability for IaaS, PaaS and SaaS in the Cloud

    - by BuckWoody
    Outages, natural disasters and unforeseen events have proved that even in a distributed architecture, you need to plan for High Availability (HA). In this entry I'll explain a few considerations for HA within Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). In a separate post I'll talk more about Disaster Recovery (DR), since each paradigm has a different way to handle that. Planning for HA in IaaS IaaS involves Virtual Machines - so in effect, an HA strategy here takes on many of the same characteristics as it would on-premises. The primary difference is that the vendor controls the hardware, so you need to verify what they do for things like local redundancy and so on from the hardware perspective. As far as what you can control and plan for, the primary factors fall into three areas: multiple instances, geographical dispersion and task-switching. In almost every cloud vendor I've studied, to ensure your application will be protected by any level of HA, you need to have at least two of the Instances (VM's) running. This makes sense, but you might assume that the vendor just takes care of that for you - they don't. If a single VM goes down (for whatever reason) then the access to it is lost. Depending on multiple factors, you might be able to recover the data, but you should assume that you can't. You should keep a sync to another location (perhaps the vendor's storage system in another geographic datacenter or to a local location) to ensure you can continue to serve your clients. You'll also need to host the same VM's in another geographical location. Everything from a vendor outage to a network path problem could prevent your users from reaching the system, so you need to have multiple locations to handle this. This means that you'll have to figure out how to manage state between the geo's. If the system goes down in the middle of a transaction, you need to figure out what part of the process the system was in, and then re-create or transfer that state to the second set of systems. If you didn't write the software yourself, this is non-trivial. You'll also need a manual or automatic process to detect the failure and re-route the traffic to your secondary location. You could flip a DNS entry (if your application can tolerate that) or invoke another process to alias the first system to the second, such as load-balancing and so on. There are many options, but all of them involve coding the state into the application layer. If you've simply moved a state-ful application to VM's, you may not be able to easily implement an HA solution. Planning for HA in PaaS Implementing HA in PaaS is a bit simpler, since it's built on the concept of stateless applications deployment. Once again, you need at least two copies of each element in the solution (web roles, worker roles, etc.) to remain available in a single datacenter. Also, you need to deploy the application again in a separate geo, but the advantage here is that you could work out a "shared storage" model such that state is auto-balanced across the world. In fact, you don't have to maintain a "DR" site, the alternate location can be live and serving clients, and only take on extra load if the other site is not available. In Windows Azure, you can use the Traffic Manager service top route the requests as a type of auto balancer. Even with these benefits, I recommend a second backup of storage in another geographic location. Storage is inexpensive; and that second copy can be used for not only HA but DR. Planning for HA in SaaS In Software-as-a-Service (such as Office 365, or Hadoop in Windows Azure) You have far less control over the HA solution, although you still maintain the responsibility to ensure you have it. Since each SaaS is different, check with the vendor on the solution for HA - and make sure you understand what they do and what you are responsible for. They may have no HA for that solution, or pin it to a particular geo, or perhaps they have a massive HA built in with automatic load balancing (which is often the case).   All of these options (with the exception of SaaS) involve higher costs for the design. Do not sacrifice reliability for cost - that will always cost you more in the end. Build in the redundancy and HA at the very outset of the project - if you try to tack it on later in the process the business will push back and potentially not implement HA. References: http://www.bing.com/search?q=windows+azure+High+Availability  (each type of implementation is different, so I'm routing you to a search on the topic - look for the "Patterns and Practices" results for the area in Azure you're interested in)

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  • Data Binding to Attached Properties

    - by Chris Gardner
    Originally posted on: http://geekswithblogs.net/freestylecoding/archive/2013/06/14/data-binding-to-attached-properties.aspx When I was working on my C#/XAML game framework, I discovered I wanted to try to data bind my sprites to background objects. That way, I could update my objects and the draw functionality would take care of the work for me. After a little experimenting and web searching, it appeared this concept was an impossible dream. Of course, when has that ever stopped me? In my typical way, I started to massively dive down the rabbit hole. I created a sprite on a canvas, and I bound it to a background object. <Canvas Name="GameField" Background="Black"> <Image Name="PlayerStrite" Source="Assets/Ship.png" Width="50" Height="50" Canvas.Left="{Binding X}" Canvas.Top="{Binding Y}"/> </Canvas> Now, we wire the UI item to the background item. public MainPage() { this.InitializeComponent(); this.Loaded += StartGame; }   void StartGame( object sender, RoutedEventArgs e ) { BindingPlayer _Player = new BindingPlayer(); _Player.X = Window.Current.Bounds.Height - PlayerSprite.Height; _Player.X = ( Window.Current.Bounds.Width - PlayerSprite.Width ) / 2.0; } Of course, now we need to actually have our background object. public class BindingPlayer : INotifyPropertyChanged { private double m_X; public double X { get { return m_X; } set { m_X = value; NotifyPropertyChanged(); } }   private double m_Y; public double Y { get { return m_Y; } set { m_Y = value; NotifyPropertyChanged(); } }   public event PropertyChangedEventHandler PropertyChanged; protected void NotifyPropertyChanged( [CallerMemberName] string p_PropertyName = null ) { if( PropertyChanged != null ) PropertyChanged( this, new PropertyChangedEventArgs( p_PropertyName ) ); } } I fired this baby up, and my sprite was correctly positioned on the screen. Maybe the sky wasn't falling after all. Wouldn't it be great if that was the case? I created some code to allow me to move the sprite, but nothing happened. This seems odd. So, I start debugging the application and stepping through code. Everything appears to be working. Time to dig a little deeper. After much profanity was spewed, I stumbled upon a breakthrough. The code only looked like it was working. What was really happening is that there was an exception being thrown in the background thread that I never saw. Apparently, the key call was the one to PropertyChanged. If PropertyChanged is not called on the UI thread, the UI thread ignores the call. Actually, it throws an exception and the background thread silently crashes. Of course, you'll never see this unless you're looking REALLY carefully. This seemed to be a simple problem. I just need to marshal this to the UI thread. Unfortunately, this object has no knowledge of this mythical UI Thread in which we speak. So, I had to pull the UI Thread out of thin air. Let's change our PropertyChanged call to look this. public event PropertyChangedEventHandler PropertyChanged; protected void NotifyPropertyChanged( [CallerMemberName] string p_PropertyName = null ) { if( PropertyChanged != null ) Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync( Windows.UI.Core.CoreDispatcherPriority.Normal, new Windows.UI.Core.DispatchedHandler( () => { PropertyChanged( this, new PropertyChangedEventArgs( p_PropertyName ) ); } ) ); } Now, we raised our notification on the UI thread. Everything is fine, people are happy, and the world moves on. You may have noticed that I didn't await my call to the dispatcher. This was intentional. If I am trying to update a slew of sprites, I don't want thread being hung while I wait my turn. Thus, I send the message and move on. It is worth nothing that this is NOT the most efficient way to do this for game programming. We'll get to that in another blog post. However, it is perfectly acceptable for a business app that is running a background task that would like to notify the UI thread of progress on a periodic basis. It is worth noting that this code was written for a Windows Store App. You can do the same thing with WP8 and WPF. The call to the marshaler changes, but it is the same idea.

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  • ADF Business Components

    - by Arda Eralp
    ADF Business Components and JDeveloper simplify the development, delivery, and customization of business applications for the Java EE platform. With ADF Business Components, developers aren't required to write the application infrastructure code required by the typical Java EE application to: Connect to the database Retrieve data Lock database records Manage transactions   ADF Business Components addresses these tasks through its library of reusable software components and through the supporting design time facilities in JDeveloper. Most importantly, developers save time using ADF Business Components since the JDeveloper design time makes typical development tasks entirely declarative. In particular, JDeveloper supports declarative development with ADF Business Components to: Author and test business logic in components which automatically integrate with databases Reuse business logic through multiple SQL-based views of data, supporting different application tasks Access and update the views from browser, desktop, mobile, and web service clients Customize application functionality in layers without requiring modification of the delivered application The goal of ADF Business Components is to make the business services developer more productive.   ADF Business Components provides a foundation of Java classes that allow your business-tier application components to leverage the functionality provided in the following areas: Simplifying Data Access Design a data model for client displays, including only necessary data Include master-detail hierarchies of any complexity as part of the data model Implement end-user Query-by-Example data filtering without code Automatically coordinate data model changes with business services layer Automatically validate and save any changes to the database   Enforcing Business Domain Validation and Business Logic Declaratively enforce required fields, primary key uniqueness, data precision-scale, and foreign key references Easily capture and enforce both simple and complex business rules, programmatically or declaratively, with multilevel validation support Navigate relationships between business domain objects and enforce constraints related to compound components   Supporting Sophisticated UIs with Multipage Units of Work Automatically reflect changes made by business service application logic in the user interface Retrieve reference information from related tables, and automatically maintain the information when the user changes foreign-key values Simplify multistep web-based business transactions with automatic web-tier state management Handle images, video, sound, and documents without having to use code Synchronize pending data changes across multiple views of data Consistently apply prompts, tooltips, format masks, and error messages in any application Define custom metadata for any business components to support metadata-driven user interface or application functionality Add dynamic attributes at runtime to simplify per-row state management   Implementing High-Performance Service-Oriented Architecture Support highly functional web service interfaces for business integration without writing code Enforce best-practice interface-based programming style Simplify application security with automatic JAAS integration and audit maintenance "Write once, run anywhere": use the same business service as plain Java class, EJB session bean, or web service   Streamlining Application Customization Extend component functionality after delivery without modifying source code Globally substitute delivered components with extended ones without modifying the application   ADF Business Components implements the business service through the following set of cooperating components: Entity object An entity object represents a row in a database table and simplifies modifying its data by handling all data manipulation language (DML) operations for you. These are basically your 1 to 1 representation of a database table. Each table in the database will have 1 and only 1 EO. The EO contains the mapping between columns and attributes. EO's also contain the business logic and validation. These are you core data services. They are responsible for updating, inserting and deleting records. The Attributes tab displays the actual mapping between attributes and columns, the mapping has following fields: Name : contains the name of the attribute we expose in our data model. Type : defines the data type of the attribute in our application. Column : specifies the column to which we want to map the attribute with Column Type : contains the type of the column in the database   View object A view object represents a SQL query. You use the full power of the familiar SQL language to join, filter, sort, and aggregate data into exactly the shape required by the end-user task. The attributes in the View Objects are actually coming from the Entity Object. In the end the VO will generate a query but you basically build a VO by selecting which EO need to participate in the VO and which attributes of those EO you want to use. That's why you have the Entity Usage column so you can see the relation between VO and EO. In the query tab you can clearly see the query that will be generated for the VO. At this stage we don't need it and just use it for information purpose. In later stages we might use it. Application module An application module is the controller of your data layer. It is responsible for keeping hold of the transaction. It exposes the data model to the view layer. You expose the VO's through the Application Module. This is the abstraction of your data layer which you want to show to the outside word.It defines an updatable data model and top-level procedures and functions (called service methods) related to a logical unit of work related to an end-user task. While the base components handle all the common cases through built-in behavior, customization is always possible and the default behavior provided by the base components can be easily overridden or augmented. When you create EO's, a foreign key will be translated into an association in our model. It defines the type of relation and who is the master and child as well as how the visibility of the association looks like. A similar concept exists to identify relations between view objects. These are called view links. These are almost identical as association except that a view link is based upon attributes defined in the view object. It can also be based upon an association. Here's a short summary: Entity Objects: representations of tables Association: Relations between EO's. Representations of foreign keys View Objects: Logical model View Links: Relationships between view objects Application Model: interface to your application  

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  • Understanding the 'High Performance' meaning in Extreme Transaction Processing

    - by kyap
    Despite my previous blogs entries on SOA/BPM and Identity Management, the domain where I'm the most passionated is definitely the Extreme Transaction Processing, commonly called XTP.I came across XTP back to 2007 while I was still FMW Product Manager in EMEA. At that time Oracle acquired a company called Tangosol, which owned an unique product called Coherence that we renamed to Oracle Coherence. Beside this innovative renaming of the product, to be honest, I didn't know much about it, except being a "distributed in-memory cache for Extreme Transaction Processing"... not very helpful still.In general when people doesn't fully understand a technology or a concept, they tend to find some shortcuts, either correct or not, to justify their lack-of understanding... and of course I was part of this category of individuals. And the shortcut was "Oracle Coherence Cache helps to improve Performance". Excellent marketing slogan... but not very meaningful still. By chance I was able to get away quickly from that group in July 2007* at Thames Valley Park (UK), after I attended one of the most interesting workshops, in my 10 years career in Oracle, delivered by Brian Oliver. The biggest mistake I made was to assume that performance improvement with Coherence was related to the response time. Which can be considered as legitimus at that time, because after-all caches help to reduce latency on cached data access, hence reduce the response-time. But like all caches, you need to define caching and expiration policies, thinking about the cache-missed strategy, and most of the time you have to re-write partially your application in order to work with the cache. At a result, the expected benefit vanishes... so, not very useful then?The key mistake I made was my perception or obsession on how performance improvement should be driven, but I strongly believe this is still a common problem to most of the developers. In fact we all know the that the performance of a system is generally presented by the Capacity (or Throughput), with the 2 important dimensions Speed (response-time) and Volume (load) :Capacity (TPS) = Volume (T) / Speed (S)To increase the Capacity, we can either reduce the Speed(in terms of response-time), or to increase the Volume. However we tend to only focus on reducing the Speed dimension, perhaps it is more concrete and tangible to measure, and nicer to present to our management because there's a direct impact onto the end-users experience. On the other hand, we assume the Volume can be addressed by the underlying hardware or software stack, so if we need more capacity (scale out), we just add more hardware or software. Unfortunately, the reality proves that IT is never as ideal as we assume...The challenge with Speed improvement approach is that it is generally difficult and costly to make things already fast... faster. And by adding Coherence will not necessarily help either. Even though we manage to do so, the Capacity can not increase forever because... the Speed can be influenced by the Volume. For all system, we always have a performance illustration as follow: In all traditional system, the increase of Volume (Transaction) will also increase the Speed (Response-Time) as some point. The reason is simple: most of the time the Application logics were not designed to scale. As an example, if you have a while-loop in your application, it is natural to conceive that parsing 200 entries will require double execution-time compared to 100 entries. If you need to "Speed-up" the execution, you can only upgrade your hardware (scale-up) with faster CPU and/or network to reduce network latency. It is technically limited and economically inefficient. And this is exactly where XTP and Coherence kick in. The primary objective of XTP is about designing applications which can scale-out for increasing the Volume, by applying coding techniques to keep the execution-time as constant as possible, independently of the number of runtime data being manipulated. It is actually not just about having an application running as fast as possible, but about having a much more predictable system, with constant response-time and linearly scale, so we can easily increase throughput by adding more hardwares in parallel. It is in general combined with the Low Latency Programming model, where we tried to optimize the network usage as much as possible, either from the programmatic angle (less network-hoops to complete a task), and/or from a hardware angle (faster network equipments). In this picture, Oracle Coherence can be considered as software-level XTP enabler, via the Distributed-Cache because it can guarantee: - Constant Data Objects access time, independently from the number of Objects and the Coherence Cluster size - Data Objects Distribution by Affinity for in-memory data grouping - In-place Data Processing for parallel executionTo summarize, Oracle Coherence is indeed useful to improve your application performance, just not in the way we commonly think. It's not about the Speed itself, but about the overall Capacity with Extreme Load while keeping consistant Speed. In the future I will keep adding new blog entries around this topic, with some sample codes experiences sharing that I capture in the last few years. In the meanwhile if you want to know more how Oracle Coherence, I strongly suggest you to start with checking how our worldwide customers are using Oracle Coherence first, then you can start playing with the product through our tutorial.Have Fun !

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  • World Backup Day

    - by red(at)work
    Here at Red Gate Towers, the SQL Backup development team have been hunkered down in their shed for the last few months, with the toolbox, blowtorch and chamois leather out, upgrading SQL Backup. When we started, autumn leaves were falling. Now we're about to finish, spring flowers are budding. If not quite a gleaming new machine, at the very least a familiar, reliable engine with some shiny new bits on it will trundle magnificently out of the workshop. One of the interesting things I've noticed about working on software development teams is that the team is together for so long 'implementing' stuff - designing, coding, testing, fixing bugs and so on - that you occasionally forget why you're doing what you're doing. Doubt creeps in. It feels like a long time since we launched this project in a fanfare of optimism and enthusiasm, and all that clarity of purpose and mission "yee-haw" has dissipated with the daily pressures of development. Every now and again, we look up from our bunker and notice all those thousands of users out there, with their different configurations and working practices and each with their own set of problems and requirements, and we ask ourselves "does anyone care about what we're doing?" Has the world moved on while we've been busy? Could we have been doing something more useful with the time and talent of all these excellent people we've assembled? In truth, you can research and test and validate all you like, but you never really know if you've done the right thing (or at least, something valuable for some users) until you release. All projects suffer this insecurity. If they don't, maybe you're not worrying enough about what you're building. The two enemies of software development are certainty and complacency. Oh, and of course, rival teams with Nerf guns. The goal of SQL Backup 7 is to make it so easy to schedule regular restores of your backups that you have no excuse not to. Why schedule a restore? Because your data is not as good as your last backup. It's only as good as your last successful restore. If you're not checking your backups by restoring them and running an integrity check on the database, you're only doing half the job. It seems that most DBAs know that this is best practice, but it can be tricky and time-consuming to set up, so it's one of those tasks that can get forgotten in the midst all the other demands on their time. Sometimes, they're just too busy firefighting. But if it was simple to do? That was our inspiration for SQL Backup 7. So it was heartening to read Brent Ozar's blog post the other day about World Backup Day. To be honest, I'd never heard of World Backup Day (Talk Like a Pirate Day, yes, but not this one); however, its emphasis on not just backing up your data but checking the validity of those backups was exactly the same message we had in mind when building SQL Backup 7. It's printed on a piece of A3 above our planning board - "Make backup verification so easy to do that no DBA has an excuse for not doing it" It's the missing piece that completes the puzzle. Simple idea, great concept, useful feature, but, as it turned out, far from straightforward to implement. The problem is the future. As Marty McFly discovered over the course of three movies, the future is uncertain and hard to predict - so when you are scheduling a restore to take place an hour, day, week or month after the backup, there are all kinds of questions that you wouldn't normally have to consider. Where will this backup live? Will it even exist at the time? Will it be split into multiple files? What will the file names be? Will it be encrypted? What files should it be restored to? SQL Backup needs to know what to expect at the time the restore job is actually run. Of course, a DBA will know the answer to all these questions, but to deliver the whole point of version 7, we wanted to make it easy for them to input that information into SQL Backup. We think we've done that. When you create your scheduled backup job, there is now an option to create a "reminder" to follow it up with a scheduled restore to verify the resulting backups. Actually, it's much more than a reminder, as it stores all the relevant data so you can click it and pre-populate the wizard with all the right settings to set up your verification restores. Simple. But, what do you think? We'd love you to try it. Post by Brian Harris

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  • Proxied calls not working as expected

    - by AndyH
    I have been modifying an application to have a cleaner client/server split to allow for load splitting and resource sharing etc. Everything is written to an interface so it was easy to add a remoting layer to the interface using a proxy. Everything worked fine. The next phase was to add a caching layer to the interface and again this worked fine and speed was improved but not as much as I would have expected. On inspection it became very clear what was going on. I feel sure that this behavior has been seen many times before and there is probably a design pattern to solve the problem but it eludes me and I'm not even sure how to describe it. It is easiest explained with an example. Let's imagine the interface is interface IMyCode { List<IThing> getLots( List<String> ); IThing getOne( String id ); } The getLots() method calls getOne() and fills up the list before returning. The interface is implemented at the client which is proxied to a remoting client which then calls the remoting server which in turn calls the implementation at the server. At the client and the server layers there is also a cache. So we have :- Client interface | Client cache | Remote client | Remote server | Server cache | Server interface If we call getOne("A") at the client interface, the call is passed to the client cache which faults. This then calls the remote client which passes the call to the remote server. This then calls the server cache which also faults and so the call is eventually passed to the server interface which actually gets the IThing. In turn the server cache is filled and finally the client cache also. If getOne("A") is again called at the client interface the client cache has the data and it gets returned immediately. If a second client called getOne("B") it would fill the server cache with "B" as well as it's own client cache. Then, when the first client calls getOne("B") the client cache faults but the server cache has the data. This is all as one would expect and works well. Now lets call getLots( [ "C", "D" ] ). This works as you would expect by calling getOne() twice but there is a subtlety here. The call to getLots() cannot directly make use of the cache. Therefore the sequence is to call the client interface which in turn calls the remote client, then the remote server and eventually the server interface. This then calls getOne() to fill the list before returning. The problem is that the getOne() calls are being satisfied at the server when ideally they should be satisfied at the client. If you imagine that the client/server link is really slow then it becomes clear why the client call is more efficient than the server call once the client cache has the data. This example is contrived to illustrate the point. The more general problem is that you cannot just keep adding proxied layers to an interface and expect it to work as you would imagine. As soon as the call goes 'through' the proxy any subsequent calls are on the proxied side rather than 'self' side. Have I failed to learn or not learned something correctly? All this is implemented in Java and I haven't used EJBs. It seems that the example may be confusing. The problem is nothing to do with cache efficiencies. It is more to do with an illusion created by the use of proxies or AOP techniques in general. When you have an object whose class implements an interface there is an assumption that a call on that object might make further calls on that same object. For example, public String getInternalString() { return InetAddress.getLocalHost().toString(); } public String getString() { return getInternalString(); } If you get an object and call getString() the result depends where the code is running. If you add a remoting proxy to the class then the result could be different for calls to getString() and getInternalString() on the same object. This is because the initial call gets 'deproxied' before the actual method is called. I find this not only confusing but I wonder how I can control this behavior especially as the use of the proxy may be by a third party. The concept is fine but the practice is certainly not what I expected. Have I missed the point somewhere?

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  • What Counts for A DBA - Logic

    - by drsql
    "There are 10 kinds of people in the world. Those who will always wonder why there are only two items in my list and those who will figured it out the first time they saw this very old joke."  Those readers who will give up immediately and get frustrated with me for not explaining it to them are not likely going to be great technical professionals of any sort, much less a programmer or administrator who will be constantly dealing with the common failures that make up a DBA's day.  Many of these people will stare at this like a dog staring at a traffic signal and still have no more idea of how to decipher the riddle. Without explanation they will give up, call the joke "stupid" and, feeling quite superior, walk away indignantly to their job likely flipping patties of meat-by-product. As a data professional or any programmer who has strayed  to this very data-oriented blog, you would, if you are worth your weight in air, either have recognized immediately what was going on, or felt a bit ignorant.  Your friends are chuckling over the joke, but why is it funny? Unfortunately you left your smartphone at home on the dresser because you were up late last night programming and were running late to work (again), so you will either have to fake a laugh or figure it out.  Digging through the joke, you figure out that the word "two" is the most important part, since initially the joke mentioned 10. Hmm, why did they spell out two, but not ten? Maybe 10 could be interpreted a different way?  As a DBA, this sort of logic comes into play every day, and sometimes it doesn't involve nerdy riddles or Star Wars folklore.  When you turn on your computer and get the dreaded blue screen of death, you don't immediately cry to the help desk and sit on your thumbs and whine about not being able to work. Do that and your co-workers will question your nerd-hood; I know I certainly would. You figure out the problem, and when you have it narrowed down, you call the help desk and tell them what the problem is, usually having to explain that yes, you did in fact try to reboot before calling.  Of course, sometimes humility does come in to play when you reach the end of your abilities, but the ‘end of abilities’ is not something any of us recognize readily. It is handy to have the ability to use logic to solve uncommon problems: It becomes especially useful when you are trying to solve a data-related problem such as a query performance issue, and the way that you approach things will tell your coworkers a great deal about your abilities.  The novice is likely to immediately take the approach of  trying to add more indexes or blaming the hardware. As you become more and more experienced, it becomes increasingly obvious that performance issues are a very complex topic. A query may be slow for a myriad of reasons, from concurrency issues, a poor query plan because of a parameter value (like parameter sniffing,) poor coding standards, or just because it is a complex query that is going to be slow sometimes. Some queries that you will deal with may have twenty joins and hundreds of search criteria, and it can take a lot of thought to determine what is going on.  You can usually figure out the problem to almost any query by using basic knowledge of how joins and queries work, together with the help of such things as the query plan, profiler or monitoring tools.  It is not unlikely that it can take a full day’s work to understand some queries, breaking them down into smaller queries to find a very tiny problem. Not every time will you actually find the problem, and it is part of the process to occasionally admit that the problem is random, and everything works fine now.  Sometimes, it is necessary to realize that a problem is outside of your current knowledge, and admit temporary defeat: You can, at least, narrow down the source of the problem by looking logically at all of the possible solutions. By doing this, you can satisfy your curiosity and learn more about what the actual problem was. For example, in the joke, had you never been exposed to the concept of binary numbers, there is no way you could have known that binary - 10 = decimal - 2, but you could have logically come to the conclusion that 10 must not mean ten in the context of the joke, and at that point you are that much closer to getting the joke and at least won't feel so ignorant.

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  • How You Helped Shape Java EE 7...

    - by reza_rahman
    I have been working with the JCP in various roles since EJB 3/Java EE 5 (much of it on my own time), eventually culminating in my decision to accept my current role at Oracle (despite it's inevitable set of unique challenges, a role I find by and large positive and fulfilling). During these years, it has always been clear to me that pretty much everyone in the JCP genuinely cares about openness, feedback and developer participation. Perhaps the most visible sign to date of this high regard for grassroots level input is a survey on Java EE 7 gathered a few months ago. The survey was designed to get open feedback on a number of critical issues central to the Java EE 7 umbrella specification including what APIs to include in the standard. When we started the survey, I don't think anyone was certain what the level of participation from developers would really be. I also think everyone was pleasantly surprised that a large number of developers (around 1100) took the time out to vote on these very important issues that could impact their own professional life. And it wasn't just a matter of the quantity of responses. I was particularly impressed with the quality of the comments made through the survey (some of which I'll try to do justice to below). With Java EE 7 under our belt and the horizons for Java EE 8 emerging, this is a good time to thank everyone that took the survey once again for their thoughts and let you know what the impact of your voice actually was. As an aside, you may be happy to know that we are working hard behind the scenes to try to put together a similar survey to help kick off the agenda for Java EE 8 (although this is by no means certain). I'll break things down by the questions asked in the survey, the responses and the resulting change in the specification. APIs to Add to Java EE 7 Full/Web Profile The first question in the survey asked which of four new candidate APIs (WebSocket, JSON-P, JBatch and JCache) should be added to the Java EE 7 Full and Web profile respectively. Developers by and large wanted all the new APIs added to the full platform. The comments expressed particularly strong support for WebSocket and JCache. Others expressed dissatisfaction over the lack of a JSON binding (as opposed to JSON processing) API. WebSocket, JSON-P and JBatch are now part of Java EE 7. In addition, the long-awaited Java EE Concurrency Utilities API was also included in the Full Profile. Unfortunately, JCache was not finalized in time for Java EE 7 and the decision was made not to hold up the Java EE release any longer. JCache continues to move forward strongly and will very likely be included in Java EE 8 (it will be available much sooner than Java EE 8 to boot). An emergent standard for JSON-B is also a strong possibility for Java EE 8. When it came to the Web Profile, developers were supportive of adding WebSocket and JSON-P, but not JBatch and JCache. Both WebSocket and JSON-P are now part of the Web Profile, now also including the already popular JAX-RS API. Enabling CDI by Default The second question asked whether CDI should be enabled in Java EE by default. The overwhelming majority of developers supported the default enablement of CDI. In addition, developers expressed a desire for better CDI/Java EE alignment (with regards to EJB and JSF in particular). Some developers expressed legitimate concerns over the performance implications of enabling CDI globally as well as the potential conflict with other JSR 330 implementations like Spring and Guice. CDI is enabled by default in Java EE 7. Respecting the legitimate concerns, CDI 1.1 was very careful to add additional controls around component scanning. While a lot of work was done in Java EE 6 and Java EE 7 around CDI alignment, further alignment is under serious consideration for Java EE 8. Consistent Usage of @Inject The third question was around using CDI/JSR 330 @Inject consistently vs. allowing JSRs to create their own injection annotations (e.g. @BatchContext). A majority of developers wanted consistent usage of @Inject. The comments again reflected a strong desire for CDI/Java EE alignment. A lot of emphasis in Java EE 7 was put into using @Inject consistently. For example, the JBatch specification is focused on using @Inject wherever possible. JAX-RS remains an exception with it's existing custom injection annotations. However, the JAX-RS specification leads understand the importance of eventual convergence, hopefully in Java EE 8. Expanding the Use of @Stereotype The fourth question was about expanding CDI @Stereotype to cover annotations across Java EE beyond just CDI. A solid majority of developers supported the idea of making @Stereotype more universal in Java EE. The comments maintained the general theme of strong support for CDI/Java EE alignment Unfortunately, there was not enough time and resources in Java EE 7 to implement this fairly pervasive feature. However, it remains a serious consideration for Java EE 8. Expanding Interceptor Use The final set of questions was about expanding interceptors further across Java EE. Developers strongly supported the concept. Along with injection, interceptors are now supported across all Java EE 7 components including Servlets, Filters, Listeners, JAX-WS endpoints, JAX-RS resources, WebSocket endpoints and so on. I hope you are encouraged by how your input to the survey helped shape Java EE 7 and continues to shape Java EE 8. Participating in these sorts of surveys is of course just one way of contributing to Java EE. Another great way to stay involved is the Adopt-A-JSR Program. A large number of developers are already participating through their local JUGs. You could of course become a Java EE JSR expert group member or observer. You should stay tuned to The Aquarium for the progress of Java EE 8 JSRs if that's something you want to look into...

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  • Eloqua Experience 2013: Mystique, Modern Marketing and Masterful Engagement

    - by Mike Stiles
    The following is a guest post from Erick Mott, a social business leader at Oracle Eloqua. There’s a growing gap between 20th century marketing and a modern marketing way of doing business. I can’t think of a better example of modern marketing in action than what more than 2,000 people experienced in San Francisco at #EE13; customer-obsession, multichannel content, and real-time engagement all coming together at one extraordinary event. This was my first Eloqua Experience as a new Oracle Eloqua employee. In weeks prior, I heard about the mystique but didn’t know what to expect. What I’ve come to understand with more clarity is everything we do revolves around customer success, and we operate and educate at all times with these five tenets in mind: 1. Targeting: Really Know Your Buyer 2. Engagement: Create a 1:1 Relationship 3. Conversion: Visualize Guided Thinking 4. Analysis: Learn What’s Working 5. Marketing Technology: Enable and Extend the Cloud Product News from Eloqua Experience 2013 We made some announcements that John Stetic, VP of Products, Oracle Eloqua covers in this brief ‘Modern Marketing Minute’ video recorded after Wednesday’s keynote; summarized below, too: Oracle Eloqua AdFocus: While understanding the impact of a specific marketing channel was formerly relegated to marketers’ wish lists, the channels we now focus on are digital, social, and mobile. AdFocus gives marketers a single platform to dynamically create, manage and measure display ads alongside owned and earned media. AdFocus enables marketers to target only key accounts or prospects you want to reach with display ads, as well as provide creative content or personalized ad copy based on their persona and activities. Oracle Eloqua Profiler: The details of what we now know about customers have expanded into a universal customer profile, which can be used to create highly targeted segments. Marketers now can take data that’s not even stored in Eloqua to help targeted and score prospects for a complete, multichannel view of the customer. Profiler gives sales reps one, detailed view of the prospect to extend views beyond Oracle Eloqua asset activity (emails, forms, page views) to any external assets stored in Oracle Eloqua. Marketing Resource Management: New capabilities create more secure and controlled access to marketing resources and data. New integrations provide greater insight into campaign resources and management through a central marketing calendar and simplify resource management. Integrated Sales and Marketing Funnel: An integrated sales and marketing funnel view gives marketing and sales users, cross-functional teams, and executive management a consistent and clear view of pipeline performance. It also quickly provides users with historical metrics across different time spans and conditions. Eloqua AppCloud: More than 20 new AppCloud partners have been added to the community, which now includes 100+ apps. Eloqua AppCloud now provides modern marketers with an even broader range of marketing applications that help expand and enrich sales and marketing efforts; easily accessible in the Topliners Community. Social Capabilities: Recent integration between Oracle Eloqua and Oracle Social Relationship Management (SRM) deliver a comprehensive, scalable and integrated modern marketing solution. New capabilities include better tracking of social activities for a more complete customer profile. Engage Facebook custom audiences with AdFocus to deliver ads and meaningful experiences through trusted social networks. Biggest and Best Eloqua Experience. There’s a lot of talk in the industry about the Marketing Cloud. At Oracle Eloqua, we have been on a mission of delivering the most advanced and integrated modern marketing technology on the planet. It’s not just a concept but reality with proven execution, as seen first-hand this week in San Francisco. In this video, Kevin Akeroyd, SVP of Oracle Eloqua, provides some highlights of what made this year’s Eloqua Experience, exceptional, including Steve Woods’ presentation about the journey of modern marketers and Andrea Ward’s conversation with Vince Gilligan, creator of the Breaking Bad television series. The 2013 Markie Awards The Oracle Eloqua Marketing Cloud was best exemplified for me as 19 Markies were awarded to customers for their exceptional creativity and results as modern marketers. Wow, what a night to remember with so many committed and talented people working to create an extraordinary experience! To learn more about how to become a modern marketer, check out these resources. We look forward to seeing you next year at Eloqua Experience. More on Erick: 20 years experience at Oracle, Ektron, Sitecore, Lyris, Habeas, Nokia, creatorbase, Mark Monitor, Cisco Systems, GlobalFluency, Sun Microsystems, Philips NV, Elm Products and CBS TV. Patent holder with agency, Fortune 500, media, and startup company expertise. @mikestiles

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  • SOA, Governance, and Drugs

    Why is IT governance important in service oriented architecture (SOA)? IT Governance provides a framework for making appropriate decisions based on company guidelines and accepted standards. This framework also outlines each stakeholder’s responsibilities and authority when making important architectural or design decisions. Furthermore, this framework of governance defines parameters and constraints that are used to give context and perspective when making decisions. The use of governance as it applies to SOA ensures that specific design principles and patterns are used when developing and maintaining services. When governance is consistently applied systems the following benefits are achieved according to Anne Thomas Manes in 2010. Governance makes sure that services conform to standard interface patterns, common data modeling practices, and promotes the incorporation of existing system functionality by building on top of other available services across a system. Governance defines development standards based on proven design principles and patterns that promote reuse and composition. Governance provides developers a set of proven design principles, standards and practices that promote the reduction in system based component dependencies.  By following these guidelines, individual components will be easier to maintain. For me personally, I am a fan of IT governance, and feel that it valuable part of any corporate IT department. However, depending on how it is implemented can really affect the value of using IT governance.  Companies need to find a way to ensure that governance does not become extreme in its policies and procedures. I know for me personally, I would really dislike working under a completely totalitarian or laissez-faire version of governance. Developers need to be able to be creative in their designs and too much governance can really impede the design process and prevent the most optimal design from being developed. On the other hand, with no governance enforced, no standards will be followed and accepted design patterns will be ignored. I have personally had to spend a lot of time working on this particular scenario and I have found that the concept of code reuse and composition is almost nonexistent.  Based on this, too much time and money is wasted on redeveloping existing aspects of an application that already exist within the system as a whole. I think moving forward we will see a staggered form of IT governance, regardless if it is for SOA or IT in general.  Depending on the size of a company and the size of its IT department,  I can see IT governance as a layered approach in that the top layer will be defined by enterprise architects that focus on abstract concepts pertaining to high level design, general  guidelines, acceptable best practices, and recommended design patterns.  The next layer will be defined by solution architects or department managers that further expand on abstracted guidelines defined by the enterprise architects. This layer will contain further definitions as to when various design patterns, coding standards, and best practices are to be applied based on the context of the solutions that are being developed by the department. The final layer will be defined by the system designer or a solutions architect assed to a project in that they will define what design patterns will be used in a solution, naming conventions, as well as outline how a system will function based on the best practices defined by the previous layers. This layered approach allows for IT departments to be flexible in that system designers have creative leeway in designing solutions to meet the needs of the business, but they must operate within the confines of the abstracted IT governance guidelines.  A real world example of this can be seen in the United States as it pertains to governance of the people in that the US government defines rules and regulations in the abstract and then the state governments take these guidelines and applies them based on the will of the people in each individual state. Furthermore, the county or city governments are the ones that actually enforce these rules based on how they are interpreted by local community.  To further define my example, the United States government defines that marijuana is illegal. Each individual state has the option to determine this regulation as it wishes in that the state of Florida determines that all uses of the drug are illegal, but the state of California legally allows the use of marijuana for medicinal purposes only. Based on these accepted practices each local government enforces these rules in that a police officer will arrest anyone in the state of Florida for having this drug on them if they walk down the street, but in California if a person has a medical prescription for the drug they will not get arrested.  REFERENCESThomas Manes, Anne. (2010). Understanding SOA Governance: http://www.soamag.com/I40/0610-2.php

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  • Why do we use the Pythagorean theorem in game physics?

    - by Starkers
    I've recently learned that we use Pythagorean theorem a lot in our physics calculations and I'm afraid I don't really get the point. Here's an example from a book to make sure an object doesn't travel faster than a MAXIMUM_VELOCITY constant in the horizontal plane: MAXIMUM_VELOCITY = <any number>; SQUARED_MAXIMUM_VELOCITY = MAXIMUM_VELOCITY * MAXIMUM_VELOCITY; function animate(){ var squared_horizontal_velocity = (x_velocity * x_velocity) + (z_velocity * z_velocity); if( squared_horizontal_velocity <= SQUARED_MAXIMUM_VELOCITY ){ scalar = squared_horizontal_velocity / SQUARED_MAXIMUM_VELOCITY; x_velocity = x_velocity / scalar; z_velocity = x_velocity / scalar; } } Let's try this with some numbers: An object is attempting to move 5 units in x and 5 units in z. It should only be able to move 5 units horizontally in total! MAXIMUM_VELOCITY = 5; SQUARED_MAXIMUM_VELOCITY = 5 * 5; SQUARED_MAXIMUM_VELOCITY = 25; function animate(){ var x_velocity = 5; var z_velocity = 5; var squared_horizontal_velocity = (x_velocity * x_velocity) + (z_velocity * z_velocity); var squared_horizontal_velocity = 5 * 5 + 5 * 5; var squared_horizontal_velocity = 25 + 25; var squared_horizontal_velocity = 50; // if( squared_horizontal_velocity <= SQUARED_MAXIMUM_VELOCITY ){ if( 50 <= 25 ){ scalar = squared_horizontal_velocity / SQUARED_MAXIMUM_VELOCITY; scalar = 50 / 25; scalar = 2.0; x_velocity = x_velocity / scalar; x_velocity = 5 / 2.0; x_velocity = 2.5; z_velocity = z_velocity / scalar; z_velocity = 5 / 2.0; z_velocity = 2.5; // new_horizontal_velocity = x_velocity + z_velocity // new_horizontal_velocity = 2.5 + 2.5 // new_horizontal_velocity = 5 } } Now this works well, but we can do the same thing without Pythagoras: MAXIMUM_VELOCITY = 5; function animate(){ var x_velocity = 5; var z_velocity = 5; var horizontal_velocity = x_velocity + z_velocity; var horizontal_velocity = 5 + 5; var horizontal_velocity = 10; // if( horizontal_velocity >= MAXIMUM_VELOCITY ){ if( 10 >= 5 ){ scalar = horizontal_velocity / MAXIMUM_VELOCITY; scalar = 10 / 5; scalar = 2.0; x_velocity = x_velocity / scalar; x_velocity = 5 / 2.0; x_velocity = 2.5; z_velocity = z_velocity / scalar; z_velocity = 5 / 2.0; z_velocity = 2.5; // new_horizontal_velocity = x_velocity + z_velocity // new_horizontal_velocity = 2.5 + 2.5 // new_horizontal_velocity = 5 } } Benefits of doing it without Pythagoras: Less lines Within those lines, it's easier to read what's going on ...and it takes less time to compute, as there are less multiplications Seems to me like computers and humans get a better deal without Pythagorean theorem! However, I'm sure I'm wrong as I've seen Pythagoras' theorem in a number of reputable places, so I'd like someone to explain me the benefit of using Pythagorean theorem to a maths newbie. Does this have anything to do with unit vectors? To me a unit vector is when we normalize a vector and turn it into a fraction. We do this by dividing the vector by a larger constant. I'm not sure what constant it is. The total size of the graph? Anyway, because it's a fraction, I take it, a unit vector is basically a graph that can fit inside a 3D grid with the x-axis running from -1 to 1, z-axis running from -1 to 1, and the y-axis running from -1 to 1. That's literally everything I know about unit vectors... not much :P And I fail to see their usefulness. Also, we're not really creating a unit vector in the above examples. Should I be determining the scalar like this: // a mathematical work-around of my own invention. There may be a cleverer way to do this! I've also made up my own terms such as 'divisive_scalar' so don't bother googling var divisive_scalar = (squared_horizontal_velocity / SQUARED_MAXIMUM_VELOCITY); var divisive_scalar = ( 50 / 25 ); var divisive_scalar = 2; var multiplicative_scalar = (divisive_scalar / (2*divisive_scalar)); var multiplicative_scalar = (2 / (2*2)); var multiplicative_scalar = (2 / 4); var multiplicative_scalar = 0.5; x_velocity = x_velocity * multiplicative_scalar x_velocity = 5 * 0.5 x_velocity = 2.5 Again, I can't see why this is better, but it's more "unit-vector-y" because the multiplicative_scalar is a unit_vector? As you can see, I use words such as "unit-vector-y" so I'm really not a maths whiz! Also aware that unit vectors might have nothing to do with Pythagorean theorem so ignore all of this if I'm barking up the wrong tree. I'm a very visual person (3D modeller and concept artist by trade!) and I find diagrams and graphs really, really helpful so as many as humanely possible please!

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  • Coherence Data Guarantees for Data Reads - Basic Terminology

    - by jpurdy
    When integrating Coherence into applications, each application has its own set of requirements with respect to data integrity guarantees. Developers often describe these requirements using expressions like "avoiding dirty reads" or "making sure that updates are transactional", but we often find that even in a small group of people, there may be a wide range of opinions as to what these terms mean. This may simply be due to a lack of familiarity, but given that Coherence sits at an intersection of several (mostly) unrelated fields, it may be a matter of conflicting vocabularies (e.g. "consistency" is similar but different in transaction processing versus multi-threaded programming). Since almost all data read consistency issues are related to the concept of concurrency, it is helpful to start with a definition of that, or rather what it means for two operations to be concurrent. Rather than implying that they occur "at the same time", concurrency is a slightly weaker statement -- it simply means that it can't be proven that one event precedes (or follows) the other. As an example, in a Coherence application, if two client members mutate two different cache entries sitting on two different cache servers at roughly the same time, it is likely that one update will precede the other by a significant amount of time (say 0.1ms). However, since there is no guarantee that all four members have their clocks perfectly synchronized, and there is no way to precisely measure the time it takes to send a given message between any two members (that have differing clocks), we consider these to be concurrent operations since we can not (easily) prove otherwise. So this leads to a question that we hear quite frequently: "Are the contents of the near cache always synchronized with the underlying distributed cache?". It's easy to see that if an update on a cache server results in a message being sent to each near cache, and then that near cache being updated that there is a window where the contents are different. However, this is irrelevant, since even if the application reads directly from the distributed cache, another thread update the cache before the read is returned to the application. Even if no other member modifies a cache entry prior to the local near cache entry being updated (and subsequently read), the purpose of reading a cache entry is to do something with the result, usually either displaying for consumption by a human, or by updating the entry based on the current state of the entry. In the former case, it's clear that if the data is updated faster than a human can perceive, then there is no problem (and in many cases this can be relaxed even further). For the latter case, the application must assume that the value might potentially be updated before it has a chance to update it. This almost aways the case with read-only caches, and the solution is the traditional optimistic transaction pattern, which requires the application to explicitly state what assumptions it made about the old value of the cache entry. If the application doesn't want to bother stating those assumptions, it is free to lock the cache entry prior to reading it, ensuring that no other threads will mutate the entry, a pessimistic approach. The optimistic approach relies on what is sometimes called a "fuzzy read". In other words, the application assumes that the read should be correct, but it also acknowledges that it might not be. (I use the qualifier "sometimes" because in some writings, "fuzzy read" indicates the situation where the application actually sees an original value and then later sees an updated value within the same transaction -- however, both definitions are roughly equivalent from an application design perspective). If the read is not correct it is called a "stale read". Going back to the definition of concurrency, it may seem difficult to precisely define a stale read, but the practical way of detecting a stale read is that is will cause the encompassing transaction to roll back if it tries to update that value. The pessimistic approach relies on a "coherent read", a guarantee that the value returned is not only the same as the primary copy of that value, but also that it will remain that way. In most cases this can be used interchangeably with "repeatable read" (though that term has additional implications when used in the context of a database system). In none of cases above is it possible for the application to perform a "dirty read". A dirty read occurs when the application reads a piece of data that was never committed. In practice the only way this can occur is with multi-phase updates such as transactions, where a value may be temporarily update but then withdrawn when a transaction is rolled back. If another thread sees that value prior to the rollback, it is a dirty read. If an application uses optimistic transactions, dirty reads will merely result in a lack of forward progress (this is actually one of the main risks of dirty reads -- they can be chained and potentially cause cascading rollbacks). The concepts of dirty reads, fuzzy reads, stale reads and coherent reads are able to describe the vast majority of requirements that we see in the field. However, the important thing is to define the terms used to define requirements. A quick web search for each of the terms in this article will show multiple meanings, so I've selected what are generally the most common variations, but it never hurts to state each definition explicitly if they are critical to the success of a project (many applications have sufficiently loose requirements that precise terminology can be avoided).

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  • Clouds, Clouds, Clouds Everywhere, Not a Drop of Rain!

    - by sxkumar
    At the recently concluded Oracle OpenWorld 2012, the center of discussion was clearly Cloud. Over the five action packed days, I got to meet a large number of customers and most of them had serious interest in all things cloud.  Public Cloud - particularly the Oracle Cloud - clearly got a lot of attention and interest. I think the use cases and the value proposition for public cloud is pretty straight forward. However, when it comes to private cloud, there were some interesting revelations.  Well, I shouldn’t really call them revelations since they are pretty consistent with what I have heard from customers at other conferences as well as during 1:1 interactions. While the interest in enterprise private cloud remains to be very high, only a handful of enterprises have truly embarked on a journey to create what the purists would call true private cloud - with capabilities such as self-service and chargeback/show back. For a large majority, today's reality is simply consolidation and virtualization - and they are quite far off from creating an agile, self-service and transparent IT infrastructure which is what the enterprise cloud is all about.  Even a handful of those who have actually implemented a close-to-real enterprise private cloud have taken an infrastructure centric approach and are seeing only limited business upside. Quite a few were frank enough to admit that chargeback and self-service isn’t something that they see an immediate need for.  This is in quite contrast to the picture being painted by all those surveys out there that show a large number of enterprises having already implemented an enterprise private cloud.  On the face of it, this seems quite contrary to the observations outlined above. So what exactly is the reality? Well, the reality is that there is undoubtedly a huge amount of interest among enterprises about transforming their legacy IT environment - which is often seen as too rigid, too fragmented, and ultimately too expensive - to something more agile, transparent and business-focused. At the same time however, there is a great deal of confusion among CIOs and architects about how to get there. This isn't very surprising given all the buzz and hype surrounding cloud computing. Every IT vendor claims to have the most unique solution and there isn't a single IT product out there that does not have a cloud angle to it. Add to this the chatter on the blogosphere, it will get even a sane mind spinning.  Consequently, most  enterprises are still struggling to fully understand the concept and value of enterprise private cloud.  Even among those who have chosen to move forward relatively early, quite a few have made their decisions more based on vendor influence/preferences rather than what their businesses actually need.  Clearly, there is a disconnect between the promise of the enterprise private cloud and the current adoption trends.  So what is the way forward?  I certainly do not claim to have all the answers. But here is a perspective that many cloud practitioners have found useful and thus worth sharing. To take a step back, the fundamental premise of the enterprise private cloud is IT transformation. It is the quest to create a more agile, transparent and efficient IT infrastructure that is driven more by business needs rather than constrained by operational and procedural inefficiencies. It is the new way of delivering and consuming IT services - where the IT organizations operate more like enablers of  strategic services rather than just being the gatekeepers of IT resources. In an enterprise private cloud environment, IT organizations are expected to empower the end users via self-service access/control and provide the business stakeholders a transparent view of how the resources are being used, what’s the cost of delivering a given service, how well are the customers being served, etc.  But the most important thing to note here is the enterprise private cloud is not just an IT project, rather it is a business initiative to create an IT setup that is more aligned with the needs of today's dynamic and highly competitive business environment. Surprised? You shouldn’t be. Just remember how the business users have been at the forefront of public cloud adoption within enterprises and private cloud is no exception.   Such a broad-based transformation makes cloud more than a technology initiative. It requires people (organizational) and process changes as well, and these changes are as critical as is the choice of right tools and technology. In my next blog,  I will share how essential it is for enterprise cloud technology to go hand-in hand with process re-engineering and organization changes to unlock true value of  enterprise cloud. I am sharing a short video from my session "Managing your private Cloud" at Oracle OpenWorld 2012. More videos from this session will be posted at the recently introduced Zero to Cloud resource page. Many other experts of Oracle enterprise private cloud solution will join me on this blog "Zero to Cloud"  and share best practices , deployment tips and information on how to plan, build, deploy, monitor, manage , meter and optimize the enterprise private cloud. We look forward to your feedback, suggestions and having an engaging conversion with you on this blog.

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  • Key Windows Phone Development Concepts

    - by Tim Murphy
    As I am doing more development in and out of the enterprise arena for Windows Phone I decide I would study for the 70-599 test.  I generally take certification tests as a way to force me to dig deeper into a technology.  Between the development and studying I decided it would be good to put a post together of key development features in Windows Phone 7 environment.  Contrary to popular belief the launch of Windows Phone 8 will not obsolete Windows Phone 7 development.  With the launch of 7.8 coming shortly and people who will remain on 7.X for the foreseeable future there are still consumers needing these apps so don’t throw out the baby with the bath water. PhoneApplicationService This is a class that every Windows Phone developer needs to become familiar with.  When it comes to application state this is your go to repository.  It also contains events that help with management of your application’s lifecycle.  You can access it like the following code sample. 1: PhoneApplicationService.Current.State["ValidUser"] = userResult; DeviceNetworkInformation This class allows you to determine the connectivity of the device and be notified when something changes with that connectivity.  If you are making web service calls you will want to check here before firing off. I have found that this class doesn’t actually work very well for determining if you have internet access.  You are better of using the following code where IsConnectedToInternet is an App level property. private void Application_Launching(object sender, LaunchingEventArgs e){ // Validate user access if (Microsoft.Phone.Net.NetworkInformation.NetworkInterface.NetworkInterfaceType != Microsoft.Phone.Net.NetworkInformation.NetworkInterfaceType.None) { IsConnectedToInternet = true; } else { IsConnectedToInternet = false; } NetworkChange.NetworkAddressChanged += new NetworkAddressChangedEventHandler(NetworkChange_NetworkAddressChanged);}void NetworkChange_NetworkAddressChanged(object sender, EventArgs e){ IsConnectedToInternet = (Microsoft.Phone.Net.NetworkInformation.NetworkInterface.NetworkInterfaceType != Microsoft.Phone.Net.NetworkInformation.NetworkInterfaceType.None);} Push Notification Push notification allows your application to receive notifications in a way that reduces the application’s power needs. This MSDN article is a good place to get the basics of push notification, but you can see the essential concept in the diagram below.  There are three types of push notification: toast, Tile and raw.  The first two work regardless of the state of the application where as raw messages are discarded if your application is not running.   Live Tiles Live tiles are one of the main differentiators of the Windows Phone platform.  They allow users to find information at a glance from their start screen without navigating into individual apps.  Knowing how to implement them can be a great boost to the attractiveness of your application. The simplest step-by-step explanation for creating live tiles is here. Local Database While your application really only has Isolated Storage as a data store there are some ways of giving you database functionality to develop against.  There are a number of open source ORM style solutions.  Probably the best and most native way I have found is to use LINQ to SQL.  It does take a significant amount of setup, but the ease of use once it is configured is worth the cost.  Rather than repeat the full concepts here I will point you to a post that I wrote previously. Tasks (Bing, Email) Leveraging built in features of the Windows Phone platform is an easy way to add functionality that would be expensive to develop on your own.  The classes that you need to make yourself familiar with are BingMapsDirectionsTask and EmailComposeTask.  This will allow your application to supply directions and give the user an email path to relay information to friends and associates. Event model Because of the ability for users to switch quickly to switch to other apps or the home screen is just one reason why knowing the Windows Phone event model is important.  You need to be able to save data so that if a user gets a phone call they can come back to exactly where they were in your application.  This means that you will need to handle such events as Launching, Activated, Deactivated and Closing at an application level.  You will probably also want to get familiar with the OnNavigatedTo and OnNavigatedFrom events at the page level.  These will give you an opportunity to save data as a user navigates through your app. Summary This is just a small portion of the concepts that you will use while building Windows Phone apps, but these are some of the most critical.  With the launch of Windows Phone 8 this list will probably expand.  Take the time to investigate these topics further and try them out in your apps. del.icio.us Tags: Windows Phone 7,Windows Phone,WP7,Software Development,70-599

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  • Building Enterprise Smartphone App &ndash; Part 2: Platforms and Features

    - by Tim Murphy
    This is part 2 in a series of posts based on a talk I gave recently at the Chicago Information Technology Architects Group.  Feel free to leave feedback. In the previous post I discussed what reasons a company might have for creating a smartphone application.  In this installment I will cover some of history and state of the different platforms as well as features that can be leveraged for building enterprise smartphone applications. Platforms Before you start choosing a platform to develop your solutions on it is good to understand how we got here and what features you can leverage. History To my memory we owe all of this to a product called the Apple Newton that came out in 1987. It was the first PDA and back then I was much more of an Apple fan.  I was very impressed with this device even though it never really went anywhere.  The Palm Pilot by US Robotics was the next major advancement in PDA. It had a simple short hand window that allowed for quick stylus entry.. Later, Windows CE came out and started the broadening of the PDA market. After that it was the Palm and CE operating systems that started showing up on cell phones and for some time these were the two dominant operating systems that were distributed with devices from multiple hardware vendors. Current The iPhone was the first smartphone to take away the stylus and give us a multi-touch interface.  It was a revolution in usability and really changed the attractiveness of smartphones for the general public.  This brought us to the beginning of the current state of the market with the concept of an online store that makes it easy for customers to get new features and functionality on demand. With Android, Google made this more than a one horse race.  Not only did they come to compete, their low cost actually made them the leading OS.  Of course what made Android so attractive also is its major fault.  It is so open that it has been a target for malware which leaves consumers exposed.  Fortunately for Google though, most consumers aren’t aware of the threat that they are under. Although Microsoft had put out one of the first smart phone operating systems with CE it had to play catch up and finally came out with the Windows Phone.  They have gone for a market approach between those of iOS and Android.  They support multiple hardware vendors like Google, but they kept a certification process for applications that is similar to Apple.  They also created a user interface that was different enough to give it a clear separation from the other two platforms. The result of all this is hundreds of millions of smartphones being sold monthly across all three platforms giving us a wide range of choices and challenges when it comes to developing solutions. Features So what are the features that make these devices flexible enough be considered for use in the enterprise? The biggest advantage of today's devices is network connectivity.  The ability to access information from multiple sources at a moment’s notice is critical for businesses.  Add to that the ability to communicate over a variety of text, voice and video modes and we have a powerful starting point. Every smartphone has a cameras and they are not just useful for posting to Instagram. We are seeing more applications such as Bing vision that allow us to scan just about any printed code or text to find information.  These capabilities have been made available to developers in the form of standard libraries for reading barcodes of just about an flavor and optical character recognition (OCR) interpretation. Bluetooth give us the ability to communicate with multiple devices. Whether these are headsets, keyboard or printers the wireless communication capabilities are just starting to evolve.  The more these wireless communication protocols grow, the more opportunities we will see to transfer data between users and a variety of devices. Local storage of information that can be called up even when the device cannot reach the network is the other big capability.  This give users the ability to work offline as well and transmit information when connections are restored. These are the tools that we have to work with to build applications that can be leveraged to gain a competitive advantage for companies that implement them. Coming Up In the third installment I will cover key concerns that you face when building enterprise smartphone apps. del.icio.us Tags: smartphones,enterprise smartphone Apps,architecture,iOS,Android,Windows Phone

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  • Increasing efficiency of N-Body gravity simulation

    - by Postman
    I'm making a space exploration type game, it will have many planets and other objects that will all have realistic gravity. I currently have a system in place that works, but if the number of planets goes above 70, the FPS decreases an practically exponential rates. I'm making it in C# and XNA. My guess is that I should be able to do gravity calculations between 100 objects without this kind of strain, so clearly my method is not as efficient as it should be. I have two files, Gravity.cs and EntityEngine.cs. Gravity manages JUST the gravity calculations, EntityEngine creates an instance of Gravity and runs it, along with other entity related methods. EntityEngine.cs public void Update() { foreach (KeyValuePair<string, Entity> e in Entities) { e.Value.Update(); } gravity.Update(); } (Only relevant piece of code from EntityEngine, self explanatory. When an instance of Gravity is made in entityEngine, it passes itself (this) into it, so that gravity can have access to entityEngine.Entities (a dictionary of all planet objects)) Gravity.cs namespace ExplorationEngine { public class Gravity { private EntityEngine entityEngine; private Vector2 Force; private Vector2 VecForce; private float distance; private float mult; public Gravity(EntityEngine e) { entityEngine = e; } public void Update() { //First loop foreach (KeyValuePair<string, Entity> e in entityEngine.Entities) { //Reset the force vector Force = new Vector2(); //Second loop foreach (KeyValuePair<string, Entity> e2 in entityEngine.Entities) { //Make sure the second value is not the current value from the first loop if (e2.Value != e.Value ) { //Find the distance between the two objects. Because Fg = G * ((M1 * M2) / r^2), using Vector2.Distance() and then squaring it //is pointless and inefficient because distance uses a sqrt, squaring the result simple cancels that sqrt. distance = Vector2.DistanceSquared(e2.Value.Position, e.Value.Position); //This makes sure that two planets do not attract eachother if they are touching, completely unnecessary when I add collision, //For now it just makes it so that the planets are not glitchy, performance is not significantly improved by removing this IF if (Math.Sqrt(distance) > (e.Value.Texture.Width / 2 + e2.Value.Texture.Width / 2)) { //Calculate the magnitude of Fg (I'm using my own gravitational constant (G) for the sake of time (I know it's 1 at the moment, but I've been changing it) mult = 1.0f * ((e.Value.Mass * e2.Value.Mass) / distance); //Calculate the direction of the force, simply subtracting the positions and normalizing works, this fixes diagonal vectors //from having a larger value, and basically makes VecForce a direction. VecForce = e2.Value.Position - e.Value.Position; VecForce.Normalize(); //Add the vector for each planet in the second loop to a force var. Force = Vector2.Add(Force, VecForce * mult); //I have tried Force += VecForce * mult, and have not noticed much of an increase in speed. } } } //Add that force to the first loop's planet's position (later on I'll instead add to acceleration, to account for inertia) e.Value.Position += Force; } } } } I have used various tips (about gravity optimizing, not threading) from THIS question (that I made yesterday). I've made this gravity method (Gravity.Update) as efficient as I know how to make it. This O(N^2) algorithm still seems to be eating up all of my CPU power though. Here is a LINK (google drive, go to File download, keep .Exe with the content folder, you will need XNA Framework 4.0 Redist. if you don't already have it) to the current version of my game. Left click makes a planet, right click removes the last planet. Mouse moves the camera, scroll wheel zooms in and out. Watch the FPS and Planet Count to see what I mean about performance issues past 70 planets. (ALL 70 planets must be moving, I've had 100 stationary planets and only 5 or so moving ones while still having 300 fps, the issue arises when 70+ are moving around) After 70 planets are made, performance tanks exponentially. With < 70 planets, I get 330 fps (I have it capped at 300). At 90 planets, the FPS is about 2, more than that and it sticks around at 0 FPS. Strangely enough, when all planets are stationary, the FPS climbs back up to around 300, but as soon as something moves, it goes right back down to what it was, I have no systems in place to make this happen, it just does. I considered multithreading, but that previous question I asked taught me a thing or two, and I see now that that's not a viable option. I've also thought maybe I could do the calculations on my GPU instead, though I don't think it should be necessary. I also do not know how to do this, it is not a simple concept and I want to avoid it unless someone knows a really noob friendly simple way to do it that will work for an n-body gravity calculation. (I have an NVidia gtx 660) Lastly I've considered using a quadtree type system. (Barnes Hut simulation) I've been told (in the previous question) that this is a good method that is commonly used, and it seems logical and straightforward, however the implementation is way over my head and I haven't found a good tutorial for C# yet that explains it in a way I can understand, or uses code I can eventually figure out. So my question is this: How can I make my gravity method more efficient, allowing me to use more than 100 objects (I can render 1000 planets with constant 300+ FPS without gravity calculations), and if I can't do much to improve performance (including some kind of quadtree system), could I use my GPU to do the calculations?

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  • WCF Data Service BeginSaveChanges not saving changes in Silverlight app

    - by Enigmativity
    I'm having a hell of a time getting WCF Data Services to work within Silverlight. I'm using the VS2010 RC. I've struggled with the cross domain issue requiring the use of clientaccesspolicy.xml & crossdomain.xml files in the web server root folder, but I just couldn't get this to work. I've resorted to putting both the Silverlight Web App & the WCF Data Service in the same project to get past this issue, but any advice here would be good. But now that I can actually see my data coming from the database and being displayed in a data grid within Silverlight I thought my troubles were over - but no. I can edit the data and the in-memory entity is changing, but when I call BeginSaveChanges (with the appropriate async EndSaveChangescall) I get no errors, but no data updates in the database. Here's my WCF Data Services code: public class MyDataService : DataService<MyEntities> { public static void InitializeService(DataServiceConfiguration config) { config.SetEntitySetAccessRule("*", EntitySetRights.All); config.SetServiceOperationAccessRule("*", ServiceOperationRights.All); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; } protected override void OnStartProcessingRequest(ProcessRequestArgs args) { base.OnStartProcessingRequest(args); HttpContext context = HttpContext.Current; HttpCachePolicy c = HttpContext.Current.Response.Cache; c.SetCacheability(HttpCacheability.ServerAndPrivate); c.SetExpires(HttpContext.Current.Timestamp.AddSeconds(60)); c.VaryByHeaders["Accept"] = true; c.VaryByHeaders["Accept-Charset"] = true; c.VaryByHeaders["Accept-Encoding"] = true; c.VaryByParams["*"] = true; } } I've pinched the OnStartProcessingRequest code from Scott Hanselman's article Creating an OData API for StackOverflow including XML and JSON in 30 minutes. Here's my code from my Silverlight app: private MyEntities _wcfDataServicesEntities; private CollectionViewSource _customersViewSource; private ObservableCollection<Customer> _customers; private void UserControl_Loaded(object sender, RoutedEventArgs e) { if (!System.ComponentModel.DesignerProperties.GetIsInDesignMode(this)) { _wcfDataServicesEntities = new MyEntities(new Uri("http://localhost:7156/MyDataService.svc/")); _customersViewSource = this.Resources["customersViewSource"] as CollectionViewSource; DataServiceQuery<Customer> query = _wcfDataServicesEntities.Customer; query.BeginExecute(result => { _customers = new ObservableCollection<Customer>(); Array.ForEach(query.EndExecute(result).ToArray(), _customers.Add); Dispatcher.BeginInvoke(() => { _customersViewSource.Source = _customers; }); }, null); } } private void button1_Click(object sender, RoutedEventArgs e) { _wcfDataServicesEntities.BeginSaveChanges(r => { var response = _wcfDataServicesEntities.EndSaveChanges(r); string[] results = new[] { response.BatchStatusCode.ToString(), response.IsBatchResponse.ToString() }; _customers[0].FinAssistCompanyName = String.Join("|", results); }, null); } The response string I get back data binds to my grid OK and shows "-1|False". My intent is to get a proof-of-concept working here and then do the appropriate separation of concerns to turn this into a simple line-of-business app. I've spent hours and hours on this. I'm being driven insane. Any ideas how to get this working?

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  • Simple C# CSV Excel export class

    - by Chris
    Thought this might be handy for someone, this is an extremely simple CSV export class that I needed. Features: Extremely simple to use Escapes commas and quotes so excel handles them fine Exports date and datetimes in timezone-proof format Without further ado: using System; using System.Data.SqlTypes; using System.IO; using System.Text; using System.Collections.Generic; /// <summary> /// Simple CSV export /// Example: /// CsvExport myExport = new CsvExport(); /// /// myExport.AddRow(); /// myExport["Region"] = "New York, USA"; /// myExport["Sales"] = 100000; /// myExport["Date Opened"] = new DateTime(2003, 12, 31); /// /// myExport.AddRow(); /// myExport["Region"] = "Sydney \"in\" Australia"; /// myExport["Sales"] = 50000; /// myExport["Date Opened"] = new DateTime(2005, 1, 1, 9, 30, 0); /// /// Then you can do any of the following three output options: /// string myCsv = myExport.Export(); /// myExport.ExportToFile("Somefile.csv"); /// byte[] myCsvData = myExport.ExportToBytes(); /// </summary> public class CsvExport { /// <summary> /// To keep the ordered list of column names /// </summary> List<string> fields = new List<string>(); /// <summary> /// The list of rows /// </summary> List<Dictionary<string, object>> rows = new List<Dictionary<string, object>>(); /// <summary> /// The current row /// </summary> Dictionary<string, object> currentRow { get { return rows[rows.Count - 1]; } } /// <summary> /// Set a value on this column /// </summary> public object this[string field] { set { // Keep track of the field names, because the dictionary loses the ordering if (!fields.Contains(field)) fields.Add(field); currentRow[field] = value; } } /// <summary> /// Call this before setting any fields on a row /// </summary> public void AddRow() { rows.Add(new Dictionary<string, object>()); } /// <summary> /// Converts a value to how it should output in a csv file /// If it has a comma, it needs surrounding with double quotes /// Eg Sydney, Australia -> "Sydney, Australia" /// Also if it contains any double quotes ("), then they need to be replaced with quad quotes[sic] ("") /// Eg "Dangerous Dan" McGrew -> """Dangerous Dan"" McGrew" /// </summary> string MakeValueCsvFriendly(object value) { if (value == null) return ""; if (value is INullable && ((INullable)value).IsNull) return ""; if (value is DateTime) { if (((DateTime)value).TimeOfDay.TotalSeconds==0) return ((DateTime)value).ToString("yyyy-MM-dd"); return ((DateTime)value).ToString("yyyy-MM-dd HH:mm:ss"); } string output = value.ToString(); if (output.Contains(",") || output.Contains("\"")) output = '"' + output.Replace("\"", "\"\"") + '"'; return output; } /// <summary> /// Output all rows as a CSV returning a string /// </summary> public string Export() { StringBuilder sb = new StringBuilder(); // The header foreach (string field in fields) sb.Append(field).Append(","); sb.AppendLine(); // The rows foreach (Dictionary<string, object> row in rows) { foreach (string field in fields) sb.Append(MakeValueCsvFriendly(row[field])).Append(","); sb.AppendLine(); } return sb.ToString(); } /// <summary> /// Exports to a file /// </summary> public void ExportToFile(string path) { File.WriteAllText(path, Export()); } /// <summary> /// Exports as raw UTF8 bytes /// </summary> public byte[] ExportToBytes() { return Encoding.UTF8.GetBytes(Export()); } }

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  • Where to Store the Protection Trial Info for Software Protection Purpose

    - by Peter Lee
    It might be duplicate with other questions, but I swear that I googled a lot and search at StackOverflow.com a lot, and I cannot find the answer to my question: In a C#.Net application, where to store the protection trial info, such as Expiration Date, Number of Used Times? I understand that, all kinds of Software Protection strategies can be cracked by a sophiscated hacker (because they can almost always get around the expiration checking step). But what I'm now going to do is just to protect it in a reasonable manner that a "common"/"advanced" user cannot screw it up. OK, in order to proof that I have googled and searched a lot at StackOverflow.com, I'm listing all the possible strategies I got: 1. Registry Entry First, some users might not have the access to even read the Registry table. Second, if we put the Protection Trial Info in a Registry Entry, the user can always find it out where it is by comparing the differences before and after the software installation. They can just simply change it. OK, you might say that we should encrypt the Protection Trial Info, yes we can do that. But what if the user just change their system date before installing? OK, you might say that we should also put a last-used date, if something is wrong, the last-used date could work as a protection guide. But what if the user just uninstall the software and delete all Registry Entries related to this software, and then reinstall the software? I have no idea on how to deal with this. Please help. A Plain File First, there are some places to put the plain file: 2.a) a simple XML file under software installation path 2.b) configuration file Again, the user can just uninstall the software and remove these plain file(s), and reinstall the software. - The Software Itself If we put the protection trial info (Expiration Date, we cannot put Number of Used Times) in the software itself, it is still susceptible to the cases I mentioned above. Furthermore, it's not even cool to do so. - A Trial Product-Key It works like a licensing process, that is, we put the Trial info into an RSA-signed string. However, it requires too many steps for a user to have a try of using the software (they might lose patience): 4.a) The user downloads the software; 4.b) The user sends an email to request a Trial Product-Key by providing user name (or email) or hardware info; 4.c) The server receives the request, RSA-signs it and send back to the user; 4.d) The user can now use it under the condition of (Expiration Date & Number of Used Times). Now, the server has a record of the user's username or hardware info, so the user will be rejected to request a second trial. Is it legal to collection hardware info? In a word, the user has to do one more extra step (request a Trial Product Key) just for having a try of using the software, which is not cool (thinking myself as a user). NOTE: This question is not about the Licensing, instead, it's about where to store the TRIAL info. After the trial expires, the user should ask for a license (CD-Key/Product-Key). I'm going to use RSA signature (bound to User Hardware)

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  • Flushing a queue using AMQP, Rabbit, and Ruby

    - by jeffshantz
    I'm developing a system in Ruby that is going to make use of RabbitMQ to send messages to a queue as it does some work. I am using: Ruby 1.9.1 Stable RabbitMQ 1.7.2 AMQP gem v0.6.7 (http://github.com/tmm1/amqp) Most of the examples I have seen on this gem have their publish calls in an EM.add_periodic_timer block. This doesn't work for what I suspect is a vast majority of use cases, and certainly not for mine. I need to publish a message as I complete some work, so putting a publish statement in an add_periodic_timer block doesn't suffice. So, I'm trying to figure out how to publish a few messages to a queue, and then "flush" it, so that any messages I've published are then delivered to my subscribers. To give you an idea of what I mean, consider the following publisher code: #!/usr/bin/ruby require 'rubygems' require 'mq' MESSAGES = ["hello","goodbye","test"] AMQP.start do queue = MQ.queue('testq') messages_published = 0 while (messages_published < 50) if (rand() < 0.4) message = MESSAGES[rand(MESSAGES.size)] puts "#{Time.now.to_s}: Publishing: #{message}" queue.publish(message) messages_published += 1 end sleep(0.1) end AMQP.stop do EM.stop end end So, this code simply loops, publishing a message with 40% probability on each iteration of the loop, and then sleeps for 0.1 seconds. It does this until 50 messages have been published, and then stops AMQP. Of course, this is just a proof of concept. Now, my subscriber code: #!/usr/bin/ruby require 'rubygems' require 'mq' AMQP.start do queue = MQ.queue('testq') queue.subscribe do |header, msg| puts "#{Time.now.to_s}: Received #{msg}" end end So, we just subscribe to the queue, and for each message received, we print it out. Great, except that the subscriber only receives all 50 messages when the publisher calls AMQP.stop. Here's the output from my publisher. It has been truncated in the middle for brevity: $ ruby publisher.rb 2010-04-14 21:45:42 -0400: Publishing: test 2010-04-14 21:45:42 -0400: Publishing: hello 2010-04-14 21:45:42 -0400: Publishing: test 2010-04-14 21:45:43 -0400: Publishing: test 2010-04-14 21:45:44 -0400: Publishing: test 2010-04-14 21:45:44 -0400: Publishing: goodbye 2010-04-14 21:45:45 -0400: Publishing: goodbye 2010-04-14 21:45:45 -0400: Publishing: test 2010-04-14 21:45:45 -0400: Publishing: test . . . 2010-04-14 21:45:55 -0400: Publishing: test 2010-04-14 21:45:55 -0400: Publishing: test 2010-04-14 21:45:55 -0400: Publishing: test 2010-04-14 21:45:55 -0400: Publishing: goodbye Next, the output from my subscriber: $ ruby consumer.rb 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received hello 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received goodbye 2010-04-14 21:45:56 -0400: Received goodbye 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received test . . . 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received test 2010-04-14 21:45:56 -0400: Received goodbye If you note the timestamps in the output, the subscriber only receives all of the messages once the publisher has stopped AMQP and exited. So, being an AMQP newb, how can I get my messages to deliver immediately? I tried putting AMQP.start and AMQP.stop in the body of the while loop of the publisher, but then only the first message gets delivered -- though strangely, if I turn on logging, there are no error messages reported by the server and the messages do get sent to the queue, but never get received by the subscriber. Suggestions would be much appreciated. Thanks for reading.

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  • Google App Engine - Secure Cookies

    - by tponthieux
    I'd been searching for a way to do cookie based authentication/sessions in Google App Engine because I don't like the idea of memcache based sessions, and I also don't like the idea of forcing users to create google accounts just to use a website. I stumbled across someone's posting that mentioned some signed cookie functions from the Tornado framework and it looks like what I need. What I have in mind is storing a user's id in a tamper proof cookie, and maybe using a decorator for the request handlers to test the authentication status of the user, and as a side benefit the user id will be available to the request handler for datastore work and such. The concept would be similar to forms authentication in ASP.NET. This code comes from the web.py module of the Tornado framework. According to the docstrings, it "Signs and timestamps a cookie so it cannot be forged" and "Returns the given signed cookie if it validates, or None." I've tried to use it in an App Engine Project, but I don't understand the nuances of trying to get these methods to work in the context of the request handler. Can someone show me the right way to do this without losing the functionality that the FriendFeed developers put into it? The set_secure_cookie, and get_secure_cookie portions are the most important, but it would be nice to be able to use the other methods as well. #!/usr/bin/env python import Cookie import base64 import time import hashlib import hmac import datetime import re import calendar import email.utils import logging def _utf8(s): if isinstance(s, unicode): return s.encode("utf-8") assert isinstance(s, str) return s def _unicode(s): if isinstance(s, str): try: return s.decode("utf-8") except UnicodeDecodeError: raise HTTPError(400, "Non-utf8 argument") assert isinstance(s, unicode) return s def _time_independent_equals(a, b): if len(a) != len(b): return False result = 0 for x, y in zip(a, b): result |= ord(x) ^ ord(y) return result == 0 def cookies(self): """A dictionary of Cookie.Morsel objects.""" if not hasattr(self,"_cookies"): self._cookies = Cookie.BaseCookie() if "Cookie" in self.request.headers: try: self._cookies.load(self.request.headers["Cookie"]) except: self.clear_all_cookies() return self._cookies def _cookie_signature(self,*parts): self.require_setting("cookie_secret","secure cookies") hash = hmac.new(self.application.settings["cookie_secret"], digestmod=hashlib.sha1) for part in parts:hash.update(part) return hash.hexdigest() def get_cookie(self,name,default=None): """Gets the value of the cookie with the given name,else default.""" if name in self.cookies: return self.cookies[name].value return default def set_cookie(self,name,value,domain=None,expires=None,path="/", expires_days=None): """Sets the given cookie name/value with the given options.""" name = _utf8(name) value = _utf8(value) if re.search(r"[\x00-\x20]",name + value): # Don't let us accidentally inject bad stuff raise ValueError("Invalid cookie %r:%r" % (name,value)) if not hasattr(self,"_new_cookies"): self._new_cookies = [] new_cookie = Cookie.BaseCookie() self._new_cookies.append(new_cookie) new_cookie[name] = value if domain: new_cookie[name]["domain"] = domain if expires_days is not None and not expires: expires = datetime.datetime.utcnow() + datetime.timedelta( days=expires_days) if expires: timestamp = calendar.timegm(expires.utctimetuple()) new_cookie[name]["expires"] = email.utils.formatdate( timestamp,localtime=False,usegmt=True) if path: new_cookie[name]["path"] = path def clear_cookie(self,name,path="/",domain=None): """Deletes the cookie with the given name.""" expires = datetime.datetime.utcnow() - datetime.timedelta(days=365) self.set_cookie(name,value="",path=path,expires=expires, domain=domain) def clear_all_cookies(self): """Deletes all the cookies the user sent with this request.""" for name in self.cookies.iterkeys(): self.clear_cookie(name) def set_secure_cookie(self,name,value,expires_days=30,**kwargs): """Signs and timestamps a cookie so it cannot be forged""" timestamp = str(int(time.time())) value = base64.b64encode(value) signature = self._cookie_signature(name,value,timestamp) value = "|".join([value,timestamp,signature]) self.set_cookie(name,value,expires_days=expires_days,**kwargs) def get_secure_cookie(self,name,include_name=True,value=None): """Returns the given signed cookie if it validates,or None""" if value is None:value = self.get_cookie(name) if not value:return None parts = value.split("|") if len(parts) != 3:return None if include_name: signature = self._cookie_signature(name,parts[0],parts[1]) else: signature = self._cookie_signature(parts[0],parts[1]) if not _time_independent_equals(parts[2],signature): logging.warning("Invalid cookie signature %r",value) return None timestamp = int(parts[1]) if timestamp < time.time() - 31 * 86400: logging.warning("Expired cookie %r",value) return None try: return base64.b64decode(parts[0]) except: return None uid=1234|1234567890|d32b9e9c67274fa062e2599fd659cc14 Parts: 1. uid is the name of the key 2. 1234 is your value in clear 3. 1234567890 is the timestamp 4. d32b9e9c67274fa062e2599fd659cc14 is the signature made from the value and the timestamp

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  • WinQual: Why would WER not accept code-signing certificates?

    - by Ian Boyd
    In 2005 i tried to establish a WinQual account with Microsoft, so i could pick up our (if any) crash dump files submitted automatically through Windows Error Reporting (WER). i was not allowed to have my crash dumps, because i don't have a Verisign certificate. Instead i have a cheaper one, generated by a Verisign subsidiary: Thawte. The method in which you join is: you digitally sign a sample exe they provide. This proves that you are the same signer that signed apps that they got crash dumps from in the wild. Cryptographically, the private key is needed to generate a digital signature on an executable. Only the holder of that private key can create a signature with for the matching public key. It doesn't matter who generated that private key. That includes certificates that are generated from: self-signing Wells Fargo DigiCert SecureTrust Trustware QuoVadis GoDaddy Entrust Cybertrust GeoTrust GlobalSign Comodo Thawte Verisign Yet Microsof's WinQual only accepts digital certificates generated by Verisign. Not even Verisign's subsidiaries are good enough (Thawte). Can anyone think of any technical, legal or ethical reason why Microsoft doesn't want to accept code-signing certificates? The WinQual site says: Why Is a Digital Certificate Required for Winqual Membership? A digital certificate helps protect your company from individuals who seek to impersonate members of your staff or who would otherwise commit acts of fraud against your company. Using a digital certificate enables proof of an identity for a user or an organization. Is somehow a Thawte digital certificate not secure? Two years later, i sent a reminder notice to WinQual that i've been waiting to be able to get at my crash dumps. The response from WinQual team was: Hello, Thanks for the reminder. We have notified the appropriate people that this is still a request. In 2008 i asked this question in a Microsoft support forum, and the response was: We are only setup to accept VeriSign Certificates at this point. We have not had an overwhelming demand to support other types of certificates. What can it possibly mean to not be "setup" to accept other kinds of certificates? If the thumbprint of the key that signed the WinQual.exe test app is the same as the thumbprint that signed the executable who's crash dump you got in the wild: it is proven - they are my crash dumps, give them to me. And it's not like there's a special API to check if a Verisign digital signature is valid, as opposed to all other digital signatures. A valid signature is valid no matter who generated the key. Microsoft is free to not trust the signer, but that's not the same as identity. So that is my question, can anyone think of any practical reason why WinQual isn't setup to support digital signatures? One person theorized that the answer is that they're just lazy: Not that I know but I would assume that the team running the winQual system is a live team and not a dev team - as in, personality and skillset geared towards maintenance of existing systems. I could be wrong though. They don't want to do work to change it. But can anyone think of anything that would need to be changed? It's the same logic no matter what generated the key: "does the thumbprint match". What am i missing?

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  • Working on a jQuery plugin : viewport simulator

    - by pixelboy
    Hi community, i'm working on a jQuery plugin that's aiming to simulate one axis camera movements. The first step to achieving this is simple : use conventional, clean markup, and get the prototype to work. Heres how to initiate the plugin : $('#wrapper').fluidGrids({exclude: '.exclude'}); Here's a working demo of the WIP thing : http://sandbox.test.everestconseil.com/protoCitroen/home.html Where am I having issues : Is there a fast way to detect if parent of each target (clickable animated element) is a href link, and if so to save this url ? My clone uses the original background image to then animate it.fade it to black/white. But when you clik on an element, image url is found, but doesn't seem to be injected. Do you see anything ? Finally, about animation of elements : as you can see in source code, I'm using the container $('#wrapper') to position all animated children. What would be the perfect properties to apply to make this cross browser proof ? Here's the source code for the plugin, fully commented. (function($){ $.fn.extend({ //plugin name - fluidGrids fluidGrids: function(options) { //List and default values for available options var defaults = { //The target that we're going to use to handle click event hitTarget: '.animateMe', exclude: '.exclude', animateSpeed: 1000 }; var options = $.extend(defaults, options); return this.each(function() { var o = options; //Assign current element to variable var obj = $(this); //We assign default width height and positions to each object in order to get them back when necessary var objPosition = obj.position(); //Get all ready to animate targets in innerViewport var items = $(o.hitTarget, obj); //Final coords of innerViewport var innerViewport = new Object(); innerViewport.top = parseInt(objPosition.top); innerViewport.left = parseInt(objPosition.left); innerViewport.bottom = obj.height(); innerViewport.right = obj.width(); items.each(function(e){ //Assign a pointer cursor to each clickable element $(this).css("cursor","pointer"); //To load distant url at last, we look for it in Title Attribute if ($(this).attr('title').length){ var targetUrl = $(this).attr('title'); } //We assign default width height and positions to each object in order to get them back when necessary var itemPosition = $(this).position(); var itemTop = itemPosition.top; var itemLeft = itemPosition.left; var itemWidth = $(this).width(); var itemHeight = $(this).height(); //Both the original and it's animated clone var original = $(this); //To give the if (original.css('background-image')){ var urlImageOriginal = original.css('background-image').replace(/^url|[("")]/g, ''); var imageToInsert = "<img src="+urlImageOriginal+"/>" } var clone = $(this).clone(); original.click(function() { $(clone).append(imageToInsert); $(clone).attr("id","clone"); $(clone).attr('top',itemTop); $(clone).attr('left',itemLeft); $(clone).css("position","absolute"); $(clone).insertAfter(this); $(this).hide(); $(clone).animate({ top: innerViewport.top, left: innerViewport.left, width: innerViewport.bottom, height: innerViewport.right }, obj.animateSpeed); $("*",obj).not("#clone, #clone * , a , "+ o.exclude).fadeOut('fast'); //Si l'objet du click est un lien return false; }); }); }); } }); })(jQuery);

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