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• WebLogic Server Performance and Tuning: Part II - Thread Management

  - by Gokhan Gungor

  WebLogic Server, like any other java application server, provides resources so that your applications use them to provide services. Unfortunately none of these resources are unlimited and they must be managed carefully. One of these resources is threads which are pooled to provide better throughput and performance along with the fast response time and to avoid deadlocks. Threads are execution points that WebLogic Server delivers its power and execute work. Managing threads is very important because it may affect the overall performance of the entire system. In previous releases of WebLogic Server 9.0 we had multiple execute queues and user defined thread pools. There were different queues for different type of work which had fixed number of execute threads.  Tuning of this thread pools and finding the proper number of threads was time consuming which required many trials. WebLogic Server 9.0 and the following releases use a single thread pool and a single priority-based execute queue. All type of work is executed in this single thread pool. Its size (thread count) is automatically decreased or increased (self-tuned). The new “self-tuning” system simplifies getting the proper number of threads and utilizing them.Work manager allows your applications to run concurrently in multiple threads. Work manager is a mechanism that allows you to manage and utilize threads and create rules/guidelines to follow when assigning requests to threads. We can set a scheduling guideline or priority a request with a work manager and then associate this work manager with one or more applications. At run-time, WebLogic Server uses these guidelines to assign pending work/requests to execution threads. The position of a request in the execute queue is determined by its priority. There is a default work manager that is provided. The default work manager should be sufficient for most applications. However there can be cases you want to change this default configuration. Your application(s) may be providing services that need mixture of fast response time and long running processes like batch updates. However wrong configuration of work managers can lead a performance penalty while expecting improvement.We can define/configure work managers at;•    Domain Level: config.xml•    Application Level: weblogic-application.xml •    Component Level: weblogic-ejb-jar.xml or weblogic.xml(For a specific web application use weblogic.xml)We can use the following predefined rules/constraints to manage the work;•    Fair Share Request Class: Specifies the average thread-use time required to process requests. The default is 50.•    Response Time Request Class: Specifies a response time goal in milliseconds.•    Context Request Class: Assigns request classes to requests based on context information.•    Min Threads Constraint: Limits the number of concurrent threads executing requests.•    Max Threads Constraint: Guarantees the number of threads the server will allocate to requests.•    Capacity Constraint: Causes the server to reject requests only when it has reached its capacity. Let’s create a work manager for our application for a long running work.Go to WebLogic console and select Environment | Work Managers from the domain structure tree. Click New button and select Work manager and click next. Enter the name for the work manager and click next. Then select the managed server instances(s) or clusters from available targets (the one that your long running application is deployed) and finish. Click on MyWorkManager, and open the Configuration tab and check Ignore Stuck Threads and save. This will prevent WebLogic to tread long running processes (that is taking more than a specified time) as stuck and enable to finish the process.

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• Synchronous Actions

  - by Dan Krasinski-Oracle

  Since the introduction of SMF, svcadm(1M) has had the ability to enable or disable a service instance and wait for that service instance to reach a final state.  With Oracle Solaris 11.2, we’ve expanded the set of administrative actions which can be invoked synchronously. Now all subcommands of svcadm(1M) have synchronous behavior. Let’s take a look at the new usage: Usage: svcadm [-v] [cmd [args ... ]] svcadm enable [-rt] [-s [-T timeout]] <service> ... enable and online service(s) svcadm disable [-t] [-s [-T timeout]] <service> ... disable and offline service(s) svcadm restart [-s [-T timeout]] <service> ... restart specified service(s) svcadm refresh [-s [-T timeout]] <service> ... re-read service configuration svcadm mark [-It] [-s [-T timeout]] <state> <service> ... set maintenance state svcadm clear [-s [-T timeout]] <service> ... clear maintenance state svcadm milestone [-d] [-s [-T timeout]] <milestone> advance to a service milestone svcadm delegate [-s] <restarter> <svc> ... delegate service to a restarter As you can see, each subcommand now has a ‘-s’ flag. That flag tells svcadm(1M) to wait for the subcommand to complete before returning. For enables, that means waiting until the instance is either ‘online’ or in the ‘maintenance’ state. For disable, the instance must reach the ‘disabled’ state. Other subcommands complete when: restart A restart is considered complete once the instance has gone offline after running the ‘stop’ method, and then has either returned to the ‘online’ state or has entered the ‘maintenance’ state. refresh If an instance is in the ‘online’ state, a refresh is considered complete once the ‘refresh’ method for the instance has finished. mark maintenance Marking an instance for maintenance completes when the instance has reached the ‘maintenance’ state. mark degraded Marking an instance as degraded completes when the instance has reached the ‘degraded’ state from the ‘online’ state. milestone A milestone transition can occur in one of two directions. Either the transition moves from a lower milestone to a higher one, or from a higher one to a lower one. When moving to a higher milestone, the transition is considered complete when the instance representing that milestone reaches the ‘online’ state. The transition to a lower milestone, on the other hand, completes only when all instances which are part of higher milestones have reached the ‘disabled’ state. That’s not the whole story. svcadm(1M) will also try to determine if the actions initiated by a particular subcommand cannot complete. Trying to enable an instance which does not have its dependencies satisfied, for example, will cause svcadm(1M) to terminate before that instance reaches the ‘online’ state. You’ll also notice the optional ‘-T’ flag which can be used in conjunction with the ‘-s’ flag. This flag sets a timeout, in seconds, after which svcadm gives up on waiting for the subcommand to complete and terminates. This is useful in many cases, but in particular when the start method for an instance has an infinite timeout but might get stuck waiting for some resource that may never become available. For the C-oriented, each of these administrative actions has a corresponding function in libscf(3SCF), with names like smf_enable_instance_synchronous(3SCF) and smf_restart_instance_synchronous(3SCF).  Take a look at smf_enable_instance_synchronous(3SCF) for details.

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• Keypress detection wont work after seemingly unrelated code change

  - by LukeZaz

  I'm trying to have the Enter key cause a new 'map' to generate for my game, but for whatever reason after implementing full-screen in it the input check won't work anymore. I tried removing the new code and only pressing one key at a time, but it still won't work. Here's the check code and the method it uses, along with the newMap method: public class Game1 : Microsoft.Xna.Framework.Game { // ... protected override void Update(GameTime gameTime) { // ... // Check if Enter was pressed - if so, generate a new map if (CheckInput(Keys.Enter, 1)) { blocks = newMap(map, blocks, console); } // ... } // Method: Checks if a key is/was pressed public bool CheckInput(Keys key, int checkType) { // Get current keyboard state KeyboardState newState = Keyboard.GetState(); bool retType = false; // Return type if (checkType == 0) { // Check Type: Is key currently down? if (newState.IsKeyDown(key)) { retType = true; } else { retType = false; } } else if (checkType == 1) { // Check Type: Was the key pressed? if (newState.IsKeyDown(key)) { if (!oldState.IsKeyDown(key)) { // Key was just pressed retType = true; } else { // Key was already pressed, return false retType = false; } } } // Save keyboard state oldState = newState; // Return result if (retType == true) { return true; } else { return false; } } // Method: Generate a new map public List<Block> newMap(Map map, List<Block> blockList, Console console) { // Create new map block coordinates List<Vector2> positions = new List<Vector2>(); positions = map.generateMap(console); // Clear list and reallocate memory previously used up by it blockList.Clear(); blockList.TrimExcess(); // Add new blocks to the list using positions created by generateMap() foreach (Vector2 pos in positions) { blockList.Add(new Block() { Position = pos, Texture = dirtTex }); } // Return modified list return blockList; } // ... } and the generateMap code: // Generate a list of Vector2 positions for blocks public List<Vector2> generateMap(Console console, int method = 0) { ScreenTileWidth = gDevice.Viewport.Width / 16; ScreenTileHeight = gDevice.Viewport.Height / 16; maxHeight = gDevice.Viewport.Height; List<Vector2> blockLocations = new List<Vector2>(); if (useScreenSize == true) { Width = ScreenTileWidth; Height = ScreenTileHeight; } else { maxHeight = Height; } int startHeight = -500; // For debugging purposes, the startHeight is set to an // hopefully-unreachable value - if it returns this, something is wrong // Methods of land generation /// <summary> /// Third version land generation /// Generates a base land height as the second version does /// but also generates a 'max change' value which determines how much /// the land can raise or lower by which it now does by a random amount /// during generation /// </summary> if (method == 0) { // Get the land height startHeight = rnd.Next(1, maxHeight); int maxChange = rnd.Next(1, 5); // Amount ground will raise/lower by int curHeight = startHeight; for (int w = 0; w < Width; w++) { // Run a chance to lower/raise ground level int changeBy = rnd.Next(1, maxChange); int doChange = rnd.Next(0, 3); if (doChange == 1 && !(curHeight <= (1 + maxChange))) { curHeight = curHeight - changeBy; } else if (doChange == 2 && !(curHeight >= (29 - maxChange))) { curHeight = curHeight + changeBy; } for (int h = curHeight; h < Height; h++) { // Location variables float x = w * 16; float y = h * 16; blockLocations.Add(new Vector2(x, y)); } } console.newMsg("[INFO] Cur, height change maximum: " + maxChange.ToString()); } /// <summary> /// Second version land generator /// Generates a solid mass of land starting at a random height /// derived from either screen height or provided height value /// </summary> else if (method == 1) { // Get the land height startHeight = rnd.Next(0, 30); for (int w = 0; w < Width; w++) { for (int h = startHeight; h < ScreenTileHeight; h++) { // Location variables float x = w * 16; float y = h * 16; // Add a tile at set location blockLocations.Add(new Vector2(x, y)); } } } /// <summary> /// First version land generator /// Generates land completely randomly either across screen or /// in a box set by Width and Height values /// </summary> else { // For each tile in the map... for (int w = 0; w < Width; w++) { for (int h = 0; h < Height; h++) { // Location variables float x = w * 16; float y = h * 16; // ...decide whether or not to place a tile... if (rnd.Next(0, 2) == 1) { // ...and if so, add a tile at that location. blockLocations.Add(new Vector2(x, y)); } } } } console.newMsg("[INFO] Cur, base height: " + startHeight.ToString()); return blockLocations; } I never touched any of the above code for this when it broke - changing keys won't seem to fix it. Despite this, I have camera movement set inside another Game1 method that uses WASD and works perfectly. All I did was add a few lines of code here: private int BackBufferWidth = 1280; // Added these variables private int BackBufferHeight = 800; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = BackBufferWidth; // and this graphics.PreferredBackBufferHeight = BackBufferHeight; // this Content.RootDirectory = "Content"; this.graphics.IsFullScreen = true; // and this } When I try adding a console line to be printed in the event the key is pressed, it seems that the If is never even triggered despite the correct key being pressed.

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• BizTalk: Instance Subscription: Details

  - by Leonid Ganeline

  It has interesting behavior and it is not always what we are waiting for. An orchestration can be enlisted with many subscriptions. In other word it can have several Receive shapes. Usually the first Receive uses the Activation subscription but other Receives create the Instance subscriptions. [See “Publish and Subscribe Architecture” in MSDN] Here is a sample process. This orchestration has two receives. It is a typical Sequential Convoy. [See "BizTalk Server 2004 Convoy Deep Dive" in MSDN by Stephen W. Thomas]. Let's experiment started.   There are three typical scenarios. First scenario: everything is OK Activation subscription for the Sample message is created when the orchestration the SampleProcess is enlisted. The Instance subscription is created only when the SampleProcess orchestration instance is started and it is removed when the orchestration instance is ended. So far so good, the Message_2 was delivered exactly in this time interval and was consumed. Second scenario: no consumers Three Sample_2 messages were delivered. One was delivered before the SampleProcess was started and before the instance subscription was created. Second message was delivered in the correct time interval. The third one was delivered after the SampleProcess orchestration was ended and the instance subscription was removed. Note: ·         It was not the first Sample_2 was consumed. It was first in the queue but in was not waiting, it was suspended when it was delivered to the Message Box and didn’t have any subscribers at this moment. The first and the last Sample_2 messages were Suspended (Nonresumable) in the Message Box. For each of this message we have got two (!) service instances associated with this suspended message. One service instance has the ServiceClass of Messaging, and we can see its Error Description:   The second service instance has the ServiceClass of RoutingFailureReport, and we can see its Error Description:   Third scenario: something goes wrong Two Sample_2 messages were delivered. Both were delivered in the same interval when the SampleProcess orchestration was working and the instance subscription was created and was working too. First Sample_2 was consumed. The second Sample_2 has the subscription but the subscriber, the SampleProcess orchestration, will not consume it. After the SampleProcess orchestration is ended (And only after! I will discuss this in the next article.), it is suspended (Nonresumable). In this time only one service instance associated with this kind of scenario is suspended. This service instance has the ServiceClass of Orchestration, and we can see its Error Description: In the Message tab we will see the Sample_2 message in the Suspended (Resumable) status. Note: ·         This behavior looks ambiguous. We see here the orchestration consumes the extra message(s) and gets suspended together with those extra messages. These messages are not consumed in term of “processed by orchestration”. But they are consumed in term of the “delivered to the subscriber”. The receive shape in the orchestration is not received these extra messages. But these messages are routed to the orchestration.     Unified Sequential convoy  Now one more scenario. It is the unified sequential convoy. That means the activation subscription is for the same message type as it for the instance subscription. The Sample_2 message is now the Sample message. For simplicity the SampleProcess orchestration consumes only two Sample messages. Usually the orchestration consumes a lot of messages inside loop, but now it is only two of them. First message starts the orchestration, the second message goes inside this orchestration. Then the next pair of messages follows, and so on. But if the input messages follow in shorter intervals we have got the problem. We lost messages in unpredictable manner. Note: ·         Maybe the better behavior would be if the orchestration removes the instance subscription after the message is consumed, not in the end on the orchestration. Right now it is a “feature” of the BizTalk subscription mechanism.

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• Good DBAs Do Baselines

  - by Louis Davidson

  One morning, you wake up and feel funny. You can’t quite put your finger on it, but something isn’t quite right. What now? Unless you happen to be a hypochondriac, you likely drag yourself out of bed, get on with the day and gather more “evidence”. You check your symptoms over the next few days; do you feel the same, better, worse? If better, then great, it was some temporal issue, perhaps caused by an allergic reaction to some suspiciously spicy chicken. If the same or worse then you go to the doctor for some health advice, but armed with some data to share, and having ruled out certain possible causes that are fixed with a bit of rest and perhaps an antacid. Whether you realize it or not, in comparing how you feel one day to the next, you have taken baseline measurements. In much the same way, a DBA uses baselines to gauge the gauge health of their database servers. Of course, while SQL Server is very willing to share data regarding its health and activities, it has almost no idea of the difference between good and bad. Over time, experienced DBAs develop “mental” baselines with which they can gauge the health of their servers almost as easily as their own body. They accumulate knowledge of the daily, natural state of each part of their database system, and so know instinctively when one of their databases “feels funny”. Equally, they know when an “issue” is just a passing tremor. They see their SQL Server with all of its four CPU cores running close 100% and don’t panic anymore. Why? It’s 5PM and every day the same thing occurs when the end-of-day reports, which are very CPU intensive, are running. Equally, they know when they need to respond in earnest when it is the first time they have heard about an issue, even if it has been happening every day. Nevertheless, no DBA can retain mental baselines for every characteristic of their systems, so we need to collect physical baselines too. In my experience, surprisingly few DBAs do this very well. Part of the problem is that SQL Server provides a lot of instrumentation. If you look, you will find an almost overwhelming amount of data regarding user activity on your SQL Server instances, and use and abuse of the available CPU, I/O and memory. It seems like a huge task even to work out which data you need to collect, let alone start collecting it on a regular basis, managing its storage over time, and performing detailed comparative analysis. However, without baselines, though, it is very difficult to pinpoint what ails a server, just by looking at a single snapshot of the data, or to spot retrospectively what caused the problem by examining aggregated data for the server, collected over many months. It isn’t as hard as you think to get started. You’ve probably already established some troubleshooting queries of the type SELECT Value FROM SomeSystemTableOrView. Capturing a set of baseline values for such a query can be as easy as changing it as follows: INSERT into BaseLine.SomeSystemTable (value, captureTime) SELECT Value, SYSDATETIME() FROM SomeSystemTableOrView; Of course, there are monitoring tools that will collect and manage this baseline data for you, automatically, and allow you to perform comparison of metrics over different periods. However, to get yourself started and to prove to yourself (or perhaps the person who writes the checks for tools) the value of baselines, stick something similar to the above query into an agent job, running every hour or so, and you are on your way with no excuses! Then, the next time you investigate a slow server, and see x open transactions, y users logged in, and z rows added per hour in the Orders table, compare to your baselines and see immediately what, if anything, has changed!

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• BI Applications overview

  - by sv744

  Welcome to Oracle BI applications blog! This blog will talk about various features, general roadmap, description of functionality and implementation steps related to Oracle BI applications. In the first post we start with an overview of the BI apps and will delve deeper into some of the topics below in the upcoming weeks and months. If there are other topics you would like us to talk about, pl feel free to provide feedback on that. The Oracle BI applications are a set of pre-built applications that enable pervasive BI by providing role-based insight for each functional area, including sales, service, marketing, contact center, finance, supplier/supply chain, HR/workforce, and executive management. For example, Sales Analytics includes role-based applications for sales executives, sales management, as well as front-line sales reps, each of whom have different needs. The applications integrate and transform data from a range of enterprise sources—including Siebel, Oracle, PeopleSoft, SAP, and others—into actionable intelligence for each business function and user role. This blog  starts with the key benefits and characteristics of Oracle BI applications. In a series of subsequent blogs, each of these points will be explained in detail. Why BI apps? Demonstrate the value of BI to a business user, show reports / dashboards / model that can answer their business questions as part of the sales cycle. Demonstrate technical feasibility of BI project and significantly lower risk and improve success Build Vs Buy benefit Don’t have to start with a blank sheet of paper. Help consolidate disparate systems Data integration in M&A situations Insulate BI consumers from changes in the OLTP Present OLTP data and highlight issues of poor data / missing data – and improve data quality and accuracy Prebuilt Integrations BI apps support prebuilt integrations against leading ERP sources: Fusion Applications, E- Business Suite, Peoplesoft, JD Edwards, Siebel, SAP Co-developed with inputs from functional experts in BI and Applications teams. Out of the box dimensional model to source model mappings Multi source and Multi Instance support Rich Data Model    BI apps have a very rich dimensionsal data model built over 10 years that incorporates best practises from BI modeling perspective as well as reflect the source system complexities  Thanks for reading a long post, and be on the lookout for future posts.  We will look forward to your valuable feedback on these topics as well as suggestions on what other topics would you like us to cover. I Conformed dimensional model across all business subject areas allows cross functional reporting, e.g. customer / supplier 360 Over 360 fact tables across 7 product areas CRM – 145, SCM – 47, Financials – 28, Procurement – 20, HCM – 27, Projects – 18, Campus Solutions – 21, PLM - 56 Supported by 300 physical dimensions Support for extensive calendars; Gregorian, enterprise and ledger based Conformed data model and metrics for real time vs warehouse based reporting  Multi-tenant enabled Extensive BI related transformations BI apps ETL and data integration support various transformations required for dimensional models and reporting requirements. All these have been distilled into common patterns and abstracted logic which can be readily reused across different modules Slowly Changing Dimension support Hierarchy flattening support Row / Column Hybrid Hierarchy Flattening As Is vs. As Was hierarchy support Currency Conversion :-  Support for 3 corporate, CRM, ledger and transaction currencies UOM conversion Internationalization / Localization Dynamic Data translations Code standardization (Domains) Historical Snapshots Cycle and process lifecycle computations Balance Facts Equalization of GL accounting chartfields/segments Standardized values for categorizing GL accounts Reconciliation between GL and subledgers to track accounted/transferred/posted transactions to GL Materialization of data only available through costly and complex APIs e.g. Fusion Payroll, EBS / Fusion Accruals Complex event Interpretation of source data – E.g. o    What constitutes a transfer o    Deriving supervisors via position hierarchy o    Deriving primary assignment in PSFT o    Categorizing and transposition to measures of Payroll Balances to specific metrics to support side by side comparison of measures of for example Fixed Salary, Variable Salary, Tax, Bonus, Overtime Payments. o    Counting of Events – E.g. converting events to fact counters so that for example the number of hires can easily be added up and compared alongside the total transfers and terminations. Multi pass processing of multiple sources e.g. headcount, salary, promotion, performance to allow side to side comparison. Adding value to data to aid analysis through banding, additional domain classifications and groupings to allow higher level analytical reporting and data discovery Calculation of complex measures examples: o    COGs, DSO, DPO, Inventory turns  etc o    Transfers within a Hierarchy or out of / into a hierarchy relative to view point in hierarchy. Configurability and Extensibility support  BI apps offer support for extensibility for various entities as automated extensibility or part of extension methodology Key Flex fields and Descriptive Flex support  Extensible attribute support (JDE)  Conformed Domains ETL Architecture BI apps offer a modular adapter architecture which allows support of multiple product lines into a single conformed model Multi Source Multi Technology Orchestration – creates load plan taking into account task dependencies and customers deployment to generate a plan based on a customers of multiple complex etl tasks Plan optimization allowing parallel ETL tasks Oracle: Bit map indexes and partition management High availability support    Follow the sun support. TCO BI apps support several utilities / capabilities that help with overall total cost of ownership and ensure a rapid implementation Improved cost of ownership – lower cost to deploy On-going support for new versions of the source application Task based setups flows Data Lineage Functional setup performed in Web UI by Functional person Configuration Test to Production support Security BI apps support both data and object security enabling implementations to quickly configure the application as per the reporting security needs Fine grain object security at report / dashboard and presentation catalog level Data Security integration with source systems  Extensible to support external data security rules Extensive Set of KPIs Over 7000 base and derived metrics across all modules Time series calculations (YoY, % growth etc) Common Currency and UOM reporting Cross subject area KPIs (analyzing HR vs GL data, drill from GL to AP/AR, etc) Prebuilt reports and dashboards 3000+ prebuilt reports supporting a large number of industries Hundreds of role based dashboards Dynamic currency conversion at dashboard level Highly tuned Performance The BI apps have been tuned over the years for both a very performant ETL and dashboard performance. The applications use best practises and advanced database features to enable the best possible performance. Optimized data model for BI and analytic queries Prebuilt aggregates& the ability for customers to create their own aggregates easily on warehouse facts allows for scalable end user performance Incremental extracts and loads Incremental Aggregate build Automatic table index and statistics management Parallel ETL loads Source system deletes handling Low latency extract with Golden Gate Micro ETL support Bitmap Indexes Partitioning support Modularized deployment, start small and add other subject areas seamlessly Source Specfic Staging and Real Time Schema Support for source specific operational reporting schema for EBS, PSFT, Siebel and JDE Application Integrations The BI apps also allow for integration with source systems as well as other applications that provide value add through BI and enable BI consumption during operational decision making Embedded dashboards for Fusion, EBS and Siebel applications Action Link support Marketing Segmentation Sales Predictor Dashboard Territory Management External Integrations The BI apps data integration choices include support for loading extenral data External data enrichment choices : UNSPSC, Item class etc. Extensible Spend Classification Broad Deployment Choices Exalytics support Databases :  Oracle, Exadata, Teradata, DB2, MSSQL ETL tool of choice : ODI (coming), Informatica Extensible and Customizable Extensible architecture and Methodology to add custom and external content Upgradable across releases

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• Super constructor must be a first statement in Java constructor [closed]

  - by Val

  I know the answer: "we need rules to prevent shooting into your own foot". Ok, I make millions of programming mistakes every day. To be prevented, we need one simple rule: prohibit all JLS and do not use Java. If we explain everything by "not shooting your foot", this is reasonable. But there is not much reason is such reason. When I programmed in Delphy, I always wanted the compiler to check me if I read uninitializable. I have discovered myself that is is stupid to read uncertain variable because it leads unpredictable result and is errorenous obviously. By just looking at the code I could see if there is an error. I wished if compiler could do this job. It is also a reliable signal of programming error if function does not return any value. But I never wanted it do enforce me the super constructor first. Why? You say that constructors just initialize fields. Super fields are derived; extra fields are introduced. From the goal point of view, it does not matter in which order you initialize the variables. I have studied parallel architectures and can say that all the fields can even be assigned in parallel... What? Do you want to use the unitialized fields? Stupid people always want to take away our freedoms and break the JLS rules the God gives to us! Please, policeman, take away that person! Where do I say so? I'm just saying only about initializing/assigning, not using the fields. Java compiler already defends me from the mistake of accessing notinitialized. Some cases sneak but this example shows how this stupid rule does not save us from the read-accessing incompletely initialized in construction: public class BadSuper { String field; public String toString() { return "field = " + field; } public BadSuper(String val) { field = val; // yea, superfirst does not protect from accessing // inconstructed subclass fields. Subclass constr // must be called before super()! System.err.println(this); } } public class BadPost extends BadSuper { Object o; public BadPost(Object o) { super("str"); this. o = o; } public String toString() { // superconstructor will boom here, because o is not initialized! return super.toString() + ", obj = " + o.toString(); } public static void main(String[] args) { new BadSuper("test 1"); new BadPost(new Object()); } } It shows that actually, subfields have to be inilialized before the supreclass! Meantime, java requirement "saves" us from writing specializing the class by specializing what the super constructor argument is, public class MyKryo extends Kryo { class MyClassResolver extends DefaultClassResolver { public Registration register(Registration registration) { System.out.println(MyKryo.this.getDepth()); return super.register(registration); } } MyKryo() { // cannot instantiate MyClassResolver in super super(new MyClassResolver(), new MapReferenceResolver()); } } Try to make it compilable. It is always pain. Especially, when you cannot assign the argument later. Initialization order is not important for initialization in general. I could understand that you should not use super methods before initializing super. But, the requirement for super to be the first statement is different. It only saves you from the code that does useful things simply. I do not see how this adds safety. Actually, safety is degraded because we need to use ugly workarounds. Doing post-initialization, outside the constructors also degrades safety (otherwise, why do we need constructors?) and defeats the java final safety reenforcer. To conclude Reading not initialized is a bug. Initialization order is not important from the computer science point of view. Doing initalization or computations in different order is not a bug. Reenforcing read-access to not initialized is good but compilers fail to detect all such bugs Making super the first does not solve the problem as it "Prevents" shooting into right things but not into the foot It requires to invent workarounds, where, because of complexity of analysis, it is easier to shoot into the foot doing post-initialization outside the constructors degrades safety (otherwise, why do we need constructors?) and that degrade safety by defeating final access modifier When there was java forum alive, java bigots attecked me for these thoughts. Particularly, they dislaked that fields can be initialized in parallel, saying that natural development ensures correctness. When I replied that you could use an advanced engineering to create a human right away, without "developing" any ape first, and it still be an ape, they stopped to listen me. Cos modern technology cannot afford it. Ok, Take something simpler. How do you produce a Renault? Should you construct an Automobile first? No, you start by producing a Renault and, once completed, you'll see that this is an automobile. So, the requirement to produce fields in "natural order" is unnatural. In case of alarmclock or armchair, which are still chair and clock, you may need first develop the base (clock and chair) and then add extra. So, I can have examples where superfields must be initialized first and, oppositely, when they need to be initialized later. The order does not exist in advance. So, the compiler cannot be aware of the proper order. Only programmer/constructor knows is. Compiler should not take more responsibility and enforce the wrong order onto programmer. Saying that I cannot initialize some fields because I did not ininialized the others is like "you cannot initialize the thing because it is not initialized". This is a kind of argument we have. So, to conclude once more, the feature that "protects" me from doing things in simple and right way in order to enforce something that does not add noticeably to the bug elimination at that is a strongly negative thing and it pisses me off, altogether with the all the arguments to support it I've seen so far. It is "a conceptual question about software development" Should there be the requirement to call super() first or not. I do not know. If you do or have an idea, you have place to answer. I think that I have provided enough arguments against this feature. Lets appreciate the ones who benefit form it. Let it just be something more than simple abstract and stupid "write your own language" or "protection" kind of argument. Why do we need it in the language that I am going to develop?

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• REST to Objects in C#

  RESTful interfaces for web services are all the rage for many Web 2.0 sites.  If you want to consume these in a very simple fashion, LINQ to XML can do the job pretty easily in C#.  If you go searching for help on this, youll find a lot of incomplete solutions and fairly large toolkits and frameworks (guess how I know this) this quick article is meant to be a no fluff just stuff approach to making this work. POCO Objects Lets assume you have a Model that you want to suck data into from a RESTful web service.  Ideally this is a Plain Old CLR Object, meaning it isnt infected with any persistence or serialization goop.  It might look something like this: public class Entry { public int Id; public int UserId; public DateTime Date; public float Hours; public string Notes; public bool Billable;   public override string ToString() { return String.Format("[{0}] User: {1} Date: {2} Hours: {3} Notes: {4} Billable {5}", Id, UserId, Date, Hours, Notes, Billable); } } Not that this isnt a completely trivial object.  Lets look at the API for the service.  RESTful HTTP Service In this case, its TickSpots API, with the following sample output: <?xml version="1.0" encoding="UTF-8"?> <entries type="array"> <entry> <id type="integer">24</id> <task_id type="integer">14</task_id> <user_id type="integer">3</user_id> <date type="date">2008-03-08</date> <hours type="float">1.00</hours> <notes>Had trouble with tribbles.</notes> <billable>true</billable> # Billable is an attribute inherited from the task <billed>true</billed> # Billed is an attribute to track whether the entry has been invoiced <created_at type="datetime">Tue, 07 Oct 2008 14:46:16 -0400</created_at> <updated_at type="datetime">Tue, 07 Oct 2008 14:46:16 -0400</updated_at> # The following attributes are derived and provided for informational purposes: <user_email>[email protected]</user_email> <task_name>Remove converter assembly</task_name> <sum_hours type="float">2.00</sum_hours> <budget type="float">10.00</budget> <project_name>Realign dilithium crystals</project_name> <client_name>Starfleet Command</client_name> </entry> </entries> Im assuming in this case that I dont necessarily care about all of the data fields the service is returning I just need some of them for my applications purposes.  Thus, you can see there are more elements in the <entry> XML than I have in my Entry class. Get The XML with C# The next step is to get the XML.  The following snippet does the heavy lifting once you pass it the appropriate URL: protected XElement GetResponse(string uri) { var request = WebRequest.Create(uri) as HttpWebRequest; request.UserAgent = ".NET Sample"; request.KeepAlive = false;   request.Timeout = 15 * 1000;   var response = request.GetResponse() as HttpWebResponse;   if (request.HaveResponse == true && response != null) { var reader = new StreamReader(response.GetResponseStream()); return XElement.Parse(reader.ReadToEnd()); } throw new Exception("Error fetching data."); } This is adapted from the Yahoo Developer article on Web Service REST calls.  Once you have the XML, the last step is to get the data back as your POCO. Use LINQ-To-XML to Deserialize POCOs from XML This is done via the following code: public IEnumerable<Entry> List(DateTime startDate, DateTime endDate) { string additionalParameters = String.Format("start_date={0}&end_date={1}", startDate.ToShortDateString(), endDate.ToShortDateString()); string uri = BuildUrl("entries", additionalParameters);   XElement elements = GetResponse(uri);   var entries = from e in elements.Elements() where e.Name.LocalName == "entry" select new Entry { Id = int.Parse(e.Element("id").Value), UserId = int.Parse(e.Element("user_id").Value), Date = DateTime.Parse(e.Element("date").Value), Hours = float.Parse(e.Element("hours").Value), Notes = e.Element("notes").Value, Billable = bool.Parse(e.Element("billable").Value) }; return entries; }   For completeness, heres the BuildUrl method for my TickSpot API wrapper: // Change these to your settings protected const string projectDomain = "DOMAIN.tickspot.com"; private const string authParams = "[email protected]&password=MyTickSpotPassword";   protected string BuildUrl(string apiMethod, string additionalParams) { if (projectDomain.Contains("DOMAIN")) { throw new ApplicationException("You must update your domain in ProjectRepository.cs."); } if (authParams.Contains("MyTickSpotPassword")) { throw new ApplicationException("You must update your email and password in ProjectRepository.cs."); } return string.Format("https://{0}/api/{1}?{2}&{3}", projectDomain, apiMethod, authParams, additionalParams); } Thats it!  Now go forth and consume XML and map it to classes you actually want to work with.  Have fun! Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• The Rise of Project Intelligence and Why It Matters

  - by Melissa Centurio Lopes

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} By Amy DeWolf Are you doing any of these in your organization? How are you leveraging historical data to forecast projects? There’s a lot going on in government today. The economic pressures agencies feel from the uncertainty of budget cuts and sequestration effect every part of an organization, including the Project Management Office (PMO).  The PMO is responsible for monitoring and administering government IT projects. As time goes on, priorities shift, technology advances, and new regulations are imposed, all of which make planning and executing projects more difficult.  For example, think about your own projects.  How many boxes do you need to check and hoops do you need to jump through to ensure you comply with new regulations? While new regulations and technology advancements can be a good thing, they add an additional layer of complexity to already complex projects. To overcome some of these pressures, particularly new regulations, many in the PMO world are adopting a new approach- Project Intelligence (PI). According to a new Oracle Primavera white paper, The Rise of Project Intelligence: When Project Management is Just Not Enough, “PI uses Business Intelligence methods to leverage historical project data to make more informed decisions and greatly enhance project execution.” Currently, project managers plan and forecast the possible phases in an execution cycle.  However, most project managers don’t have the proper tools to do this as effectively as they would like. As the white paper noted, “The underlying deficiencies in most forecasting approaches are that 1) the PM fails in most instances to leverage historical data and 2) the PM doesn’t employ current Business Intelligence tools.” PI seeks to overturn this by combining modeling tools used in Business Intelligence for projects with the understanding of Emotional Intelligence for managing people.   Simply put, Project Intelligence is built off four main pillars: Actively use historical data to forecast project cycles Understand the intricacies of complex projects Enhance social and emotional intelligence in projects Actively use Business intelligence tools Read our complimentary whitepaper and discover the importance of emotional intelligence and best practices for improving projects, specifically in terms of communication.

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• Caching factory design

  - by max

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

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• Strings in .NET are Enumerable

  - by Scott Dorman

  It seems like there is always some confusion concerning strings in .NET. This is both from developers who are new to the Framework and those that have been working with it for quite some time. Strings in the .NET Framework are represented by the System.String class, which encapsulates the data manipulation, sorting, and searching methods you most commonly perform on string data. In the .NET Framework, you can use System.String (which is the actual type name or the language alias (for C#, string). They are equivalent so use whichever naming convention you prefer but be consistent. Common usage (and my preference) is to use the language alias (string) when referring to the data type and String (the actual type name) when accessing the static members of the class. Many mainstream programming languages (like C and C++) treat strings as a null terminated array of characters. The .NET Framework, however, treats strings as an immutable sequence of Unicode characters which cannot be modified after it has been created. Because strings are immutable, all operations which modify the string contents are actually creating new string instances and returning those. They never modify the original string data. There is one important word in the preceding paragraph which many people tend to miss: sequence. In .NET, strings are treated as a sequence…in fact, they are treated as an enumerable sequence. This can be verified if you look at the class declaration for System.String, as seen below: // Summary:// Represents text as a series of Unicode characters.public sealed class String : IEnumerable, IComparable, IComparable<string>, IEquatable<string> The first interface that String implements is IEnumerable, which has the following definition: // Summary:// Exposes the enumerator, which supports a simple iteration over a non-generic// collection.public interface IEnumerable{ // Summary: // Returns an enumerator that iterates through a collection. // // Returns: // An System.Collections.IEnumerator object that can be used to iterate through // the collection. IEnumerator GetEnumerator();} As a side note, System.Array also implements IEnumerable. Why is that important to know? Simply put, it means that any operation you can perform on an array can also be performed on a string. This allows you to write code such as the following: string s = "The quick brown fox";foreach (var c in s){ System.Diagnostics.Debug.WriteLine(c);}for (int i = 0; i < s.Length; i++){ System.Diagnostics.Debug.WriteLine(s[i]);} If you executed those lines of code in a running application, you would see the following output in the Visual Studio Output window: In the case of a string, these enumerable or array operations return a char (System.Char) rather than a string. That might lead you to believe that you can get around the string immutability restriction by simply treating strings as an array and assigning a new character to a specific index location inside the string, like this: string s = "The quick brown fox";s[2] = 'a';   However, if you were to write such code, the compiler will promptly tell you that you can’t do it: This preserves the notion that strings are immutable and cannot be changed once they are created. (Incidentally, there is no built in way to replace a single character like this. It can be done but it would require converting the string to a character array, changing the appropriate indexed location, and then creating a new string.)

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• Entity Framework 6: Alpha2 Now Available

  - by ScottGu

  The Entity Framework team recently announced the 2nd alpha release of EF6.   The alpha 2 package is available for download from NuGet. Since this is a pre-release package make sure to select “Include Prereleases” in the NuGet package manager, or execute the following from the package manager console to install it: PM> Install-Package EntityFramework -Pre This week’s alpha release includes a bunch of great improvements in the following areas: Async language support is now available for queries and updates when running on .NET 4.5. Custom conventions now provide the ability to override the default conventions that Code First uses for mapping types, properties, etc. to your database. Multi-tenant migrations allow the same database to be used by multiple contexts with full Code First Migrations support for independently evolving the model backing each context. Using Enumerable.Contains in a LINQ query is now handled much more efficiently by EF and the SQL Server provider resulting greatly improved performance. All features of EF6 (except async) are available on both .NET 4 and .NET 4.5. This includes support for enums and spatial types and the performance improvements that were previously only available when using .NET 4.5. Start-up time for many large models has been dramatically improved thanks to improved view generation performance. Below are some additional details about a few of the improvements above: Async Support .NET 4.5 introduced the Task-Based Asynchronous Pattern that uses the async and await keywords to help make writing asynchronous code easier. EF 6 now supports this pattern. This is great for ASP.NET applications as database calls made through EF can now be processed asynchronously – avoiding any blocking of worker threads. This can increase scalability on the server by allowing more requests to be processed while waiting for the database to respond. The following code shows an MVC controller that is querying a database for a list of location entities:     public class HomeController : Controller     {         LocationContext db = new LocationContext();           public async Task<ActionResult> Index()         {             var locations = await db.Locations.ToListAsync();               return View(locations);         }     } Notice above the call to the new ToListAsync method with the await keyword. When the web server reaches this code it initiates the database request, but rather than blocking while waiting for the results to come back, the thread that is processing the request returns to the thread pool, allowing ASP.NET to process another incoming request with the same thread. In other words, a thread is only consumed when there is actual processing work to do, allowing the web server to handle more concurrent requests with the same resources. A more detailed walkthrough covering async in EF is available with additional information and examples. Also a walkthrough is available showing how to use async in an ASP.NET MVC application. Custom Conventions When working with EF Code First, the default behavior is to map .NET classes to tables using a set of conventions baked into EF. For example, Code First will detect properties that end with “ID” and configure them automatically as primary keys. However, sometimes you cannot or do not want to follow those conventions and would rather provide your own. For example, maybe your primary key properties all end in “Key” instead of “Id”. Custom conventions allow the default conventions to be overridden or new conventions to be added so that Code First can map by convention using whatever rules make sense for your project. The following code demonstrates using custom conventions to set the precision of all decimals to 5. As with other Code First configuration, this code is placed in the OnModelCreating method which is overridden on your derived DbContext class:         protected override void OnModelCreating(DbModelBuilder modelBuilder)         {             modelBuilder.Properties<decimal>()                 .Configure(x => x.HasPrecision(5));           } But what if there are a couple of places where a decimal property should have a different precision? Just as with all the existing Code First conventions, this new convention can be overridden for a particular property simply by explicitly configuring that property using either the fluent API or a data annotation. A more detailed description of custom code first conventions is available here. Community Involvement I blogged a while ago about EF being released under an open source license.  Since then a number of community members have made contributions and these are included in EF6 alpha 2. Two examples of community contributions are: AlirezaHaghshenas contributed a change that increases the startup performance of EF for larger models by improving the performance of view generation. The change means that it is less often necessary to use of pre-generated views. UnaiZorrilla contributed the first community feature to EF: the ability to load all Code First configuration classes in an assembly with a single method call like the following: protected override void OnModelCreating(DbModelBuilder modelBuilder) {        modelBuilder.Configurations            .AddFromAssembly(typeof(LocationContext).Assembly); } This code will find and load all the classes that inherit from EntityTypeConfiguration<T> or ComplexTypeConfiguration<T> in the assembly where LocationContext is defined. This reduces the amount of coupling between the context and Code First configuration classes, and is also a very convenient shortcut for large models. Other upcoming features coming in EF 6 Lots of information about the development of EF6 can be found on the EF CodePlex site, including a roadmap showing the other features that are planned for EF6. One of of the nice upcoming features is connection resiliency, which will automate the process of retying database operations on transient failures common in cloud environments and with databases such as the Windows Azure SQL Database. Another often requested feature that will be included in EF6 is the ability to map stored procedures to query and update operations on entities when using Code First. Summary EF6 is the first open source release of Entity Framework being developed in CodePlex. The alpha 2 preview release of EF6 is now available on NuGet, and contains some really great features for you to try. The EF team are always looking for feedback from developers - especially on the new features such as custom Code First conventions and async support. To provide feedback you can post a comment on the EF6 alpha 2 announcement post, start a discussion or file a bug on the CodePlex site. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• Removing occurrences of characters in a string

  - by DmainEvent

  I am reading this book, programming Interviews exposed by John Wiley and sons and in chapter 6 they are discussing removing all instances of characters in a src string using a removal string... so removeChars(string str, string remove) In there writeup they sey the steps to accomplish this are to have a boolean lookup array with all values initially set to false, then loop through each character in remove setting the corresponding value in the lookup array to true (note: this could also be a hash if the possible character set where huge like Unicode-16 or something like that or if str and remove are both relatively small... < 100 characters I suppose). You then iterate through the str with a source and destination index, copying each character only if its corresponding value in the lookup array is false... Which makes sense... I don't understand the code that they use however... They have for(src = 0; src < len; ++src){ flags[r[src]] == true; } which is turning the flag value at the remove string indexed at src to true... so if you start out with PLEASE HELP as your str and LEA as your remove you will be setting in your flag table at 0,1,2... t|t|t but after that you will get an out of bounds exception because r doesn't have have anything greater than 2 in it... even using there example you get an out of bounds exception... Am is there code example unworkable? Entire function string removeChars( string str, string remove ){ char[] s = str.toCharArray(); char[] r = remove.toCharArray(); bool[] flags = new bool[128]; // assumes ASCII! int len = s.Length; int src, dst; // Set flags for characters to be removed for( src = 0; src < len; ++src ){ flags[r[src]] = true; } src = 0; dst = 0; // Now loop through all the characters, // copying only if they aren’t flagged while( src < len ){ if( !flags[ (int)s[src] ] ){ s[dst++] = s[src]; } ++src; } return new string( s, 0, dst ); } as you can see, r comes from the remove string. So in my example the remove string has only a size of 3 while my str string has a size of 11. len is equal to the length of the str string. So it would be 11. How can I loop through the r string since it is only size 3? I haven't compiled the code so I can loop through it, but just looking at it I know it won't work. I am thinking they wanted to loop through the r string... in other words they got the length of the wrong string here.

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• Consolidation in a Database Cloud

  - by B R Clouse

  Consolidation of multiple databases onto a shared infrastructure is the next step after Standardization.  The potential consolidation density is a function of the extent to which the infrastructure is shared.  The three models provide increasing degrees of sharing: Server: each database is deployed in a dedicated VM. Hardware is shared, but most of the software infrastructure is not. Standardization is often applied incompletely since operating environments can be moved as-is onto the shared platform. The potential for VM sprawl is an additional downside. Database: multiple database instances are deployed on a shared software / hardware infrastructure. This model is very efficient and easily implemented with the features in the Oracle Database and supporting products. Many customers have moved to this model and achieved significant, measurable benefits. Schema: multiple schemas are deployed within a single database instance. The most efficient model, it places constraints on the environment. Usually this model will be implemented only by customers deploying their own applications.  (Note that a single deployment can combine Database and Schema consolidations.) Customer value: lower costs, better system utilization In this phase of the maturity model, under-utilized hardware can be used to host more workloads, or retired and those workloads migrated to consolidation platforms. Customers benefit from higher utilization of the hardware resources, resulting in reduced data center floor space, and lower power and cooling costs. And, the OpEx savings from Standardization are multiplied, since there are fewer physical components (both hardware and software) to manage. Customer value: higher productivity The OpEx benefits from Standardization are compounded since not only are there fewer types of things to manage, now there are fewer entities to manage. In this phase, customers discover that their IT staff has time to move away from "day-to-day" tasks and start investing in higher value activities. Database users benefit from consolidating onto shared infrastructures by relieving themselves of the requirement to maintain their own dedicated servers. Also, if the shared infrastructure offers capabilities such as High Availability / Disaster Recovery, which are often beyond the budget and skillset of a standalone database environment, then moving to the consolidation platform can provide access to those capabilities, resulting in less downtime. Capabilities / Characteristics In this phase, customers will typically deploy fixed-size clusters and consolidate on a cluster until that cluster is deemed "full," at which point a new cluster is built. Customers will define one or a few cluster architectures that are used wherever possible; occasionally there may be deployments which must be handled as exceptions. The "full" policy may be based on number of databases deployed on the cluster, or observed peak workload, etc. IT will own the provisioning of new databases on a cluster, making the decision of when and where to place new workloads. Resources may be managed dynamically, e.g., as a priority workload increases, it may be given more CPU and memory to handle the spike. Users will be charged at a fixed, relatively coarse level; or in some cases, no charging will be applied. Activities / Tasks Oracle offers several tools to plan a successful consolidation. Real Application Testing (RAT) has a feature to help plan and validate database consolidations. Enterprise Manager 12c's Cloud Management Pack for Database includes a planning module. Looking ahead, customers should start planning for the Services phase by defining the Service Catalog that will be made available for database services.

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• OpenGL Fast-Object Instancing Error

  - by HJ Media Studios

  I have some code that loops through a set of objects and renders instances of those objects. The list of objects that needs to be rendered is stored as a std::map, where an object of class MeshResource contains the vertices and indices with the actual data, and an object of classMeshRenderer defines the point in space the mesh is to be rendered at. My rendering code is as follows: glDisable(GL_BLEND); glEnable(GL_CULL_FACE); glDepthMask(GL_TRUE); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glEnable(GL_DEPTH_TEST); for (std::map<MeshResource*, std::vector<MeshRenderer*> >::iterator it = renderables.begin(); it != renderables.end(); it++) { it->first->setupBeforeRendering(); cout << "<"; for (unsigned long i =0; i < it->second.size(); i++) { //Pass in an identity matrix to the vertex shader- used here only for debugging purposes; the real code correctly inputs any matrix. uniformizeModelMatrix(Matrix4::IDENTITY); /** * StartHere fix rendering problem. * Ruled out: * Vertex buffers correctly. * Index buffers correctly. * Matrices correct? */ it->first->render(); } it->first->cleanupAfterRendering(); } geometryPassShader->disable(); glDepthMask(GL_FALSE); glDisable(GL_CULL_FACE); glDisable(GL_DEPTH_TEST); The function in MeshResource that handles setting up the uniforms is as follows: void MeshResource::setupBeforeRendering() { glEnableVertexAttribArray(0); glEnableVertexAttribArray(1); glEnableVertexAttribArray(2); glEnableVertexAttribArray(3); glEnableVertexAttribArray(4); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, iboID); glBindBuffer(GL_ARRAY_BUFFER, vboID); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0); // Vertex position glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 12); // Vertex normal glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 24); // UV layer 0 glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 32); // Vertex color glVertexAttribPointer(4, 1, GL_UNSIGNED_SHORT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 44); //Material index } The code that renders the object is this: void MeshResource::render() { glDrawElements(GL_TRIANGLES, geometry->numIndices, GL_UNSIGNED_SHORT, 0); } And the code that cleans up is this: void MeshResource::cleanupAfterRendering() { glDisableVertexAttribArray(0); glDisableVertexAttribArray(1); glDisableVertexAttribArray(2); glDisableVertexAttribArray(3); glDisableVertexAttribArray(4); } The end result of this is that I get a black screen, although the end of my rendering pipeline after the rendering code (essentially just drawing axes and lines on the screen) works properly, so I'm fairly sure it's not an issue with the passing of uniforms. If, however, I change the code slightly so that the rendering code calls the setup immediately before rendering, like so: void MeshResource::render() { setupBeforeRendering(); glDrawElements(GL_TRIANGLES, geometry->numIndices, GL_UNSIGNED_SHORT, 0); } The program works as desired. I don't want to have to do this, though, as my aim is to set up vertex, material, etc. data once per object type and then render each instance updating only the transformation information. The uniformizeModelMatrix works as follows: void RenderManager::uniformizeModelMatrix(Matrix4 matrix) { glBindBuffer(GL_UNIFORM_BUFFER, globalMatrixUBOID); glBufferSubData(GL_UNIFORM_BUFFER, 0, sizeof(Matrix4), matrix.ptr()); glBindBuffer(GL_UNIFORM_BUFFER, 0); }

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• UIViewController presentModalViewController: animated: doing nothing?

  - by ryyst

  Hi, I recently started a project, using Apple's Utility Application example project. In the example project, there's an info button that shows an instance of FlipSideView. If you know the Weather.app, you know what the button acts like. I then changed the MainWindow.xib to contain a scrollview in the middle of the window and a page-control view at the bottom of the window (again, like the Weather.app). The scrollview gets filled with instances of MainView. When I then clicked the info button, the FlipSideView would show, but only in the area that was previously filled by the MainView instance – this means that the page-control view on the bottom of the page still showed when the FlipSideView instance got loaded. So, I thought that I would simply add a UIViewController for the top-most window, which is the one declared inside the AppDelegate created along side with the project. So, I created a subclass of UIViewController, put an instance of it inside MainWindow.xib and connected it's view outlet to the UIWindow declared as window inside the app delegate. I also changed the button's action, so that it know sends a message to the MainWindowController instance. The message does get sent (I checked with NSLog() statements), but the FlipSideView doesn't get shown. Here's the relevant (?) code: FlipsideViewController *controller = [[FlipsideViewController alloc] initWithNibName:@"FlipsideView" bundle:nil]; controller.delegate = self; controller.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal; [self presentModalViewController:controller animated:YES]; [controller release]; Why's this not working? I've uploaded the entire project here for you to be able to see the whole thing. Thanks for help! -- Ry

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• Overlay WPF controls

  - by sandy

  Hello I've written an 'auto-suggest' textbox user control in WPF. It behaves a little bit like the 'To' list in Hotmail, allowing the user to enter a list of items, offering suggestions when it is able. The main controls are a a text box, a wrap panel and a list box. The text box captures user input. The wrap panel contains the text box and shows previous entries. The list box is used to show suggestions. Most of the time, the list box is hidden. I'm using multiple instances of my control in a stack panel. My problem is that when the list box is shown, it is included in the measurement of the height of the control. This forces the following controls in the stack panel to be shifted down, as these pictures demonstrate: I've tried overriding the measurement of my control so not to include the list box, but this just results in the list box not being visible. What I want to do is make the list box overlay any subsequent controls in the stack panel, like a combo box's drop down would do. However, I really don't know how to do this. Any ideas? Thanks Sandy

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• ASPNET MVC - Override Html.TextBoxFor(model.property) with a new helper with same signature?

  - by JK

  I want to override Html.TextBoxFor() with my own helper that has the exact same signature (but a different namespace of course) - is this possible, and if so, how? The reason for this is that I have 100+ views in an already existing app, and I want to change the behaviour of TextBoxFor so that it outputs a maxLength=n attribute if the property has a [StringLength(n)] annotation. The code for automatically outputting maxlength=n is in this question: http://stackoverflow.com/questions/2386365/maxlength-attribute-of-a-text-box-from-the-dataannotations-stringlength-in-mvc2. But my question is not a duplicate - I am trying creating a more generic solution: where the DataAnnotaion flows into the html automatically without any need for additional code by the person writing the view. In the referenced question, you have to change every single Html.TexBoxFor to a Html.CustomTextBoxFor. I need to do it so that the existing TextBoxFor()'s do not need to be changed - hence creating a helper with the same signature: change the behaviour of the helper method, and all existing instances will just work without any changes (100+ views, at least 500 TextBoxFor()s - don't want to manually edit that). I tried this code: (And I need to repeat it for each overload of TextBoxFor, but once the root problem is solved, that will be trivial) namespace My.Helpers { public static class CustomTextBoxHelper { public static MvcHtmlString TextBoxFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, object htmlAttributes, bool includeLengthIfAnnotated) { // implementation here } } } But I am getting a compiler error in the view on Html.TextBoxFor(): "The call is ambiguous between the following methods or properties" (of course). Is there any way to do this? Is there an alternative approach that would allow me to change the behaviour of Html.TextBoxFor, so that the views that already use it do not need to be changed?

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• Flash AS3: (VideoEvent.COMPLETE, completePlay) - listener is triggered before video is completed

  - by Tevi

  Hello, I have a flash video using the standard FLV Playback component that comes with Flash. I'm using ActionScript 3 to modify the appearance and set up an event listener. I've set it up to go to a new URL using "externalInterface" when the video completes play. The URL is set in a variable using SWFObject. On only a few instances (3 people out of 50 - tested using Amazon Turk), people reported being taken directly to the new url, before the video even started playing. It's difficult to repeat the issue, but it did happen to me once. It doesn't have anything to do with cache, since it has been reported on people going to the url for the first time. Here's the url to the video: http://www.partstown.com/is-bin/INTERSHOP.enfinity/WFS/Reedy-PartsTown-Site/en_US/-/USD/ViewStaticPage-UnFramed?page=tourthetown Here's the code: import flash.external.*; import fl.video.*; var myVideo:FLVPlayback = new FLVPlayback(); var theUrl:String = this.loaderInfo.parameters.urlName; var theScript:String = this.loaderInfo.parameters.scriptName; myVideo.source = this.loaderInfo.parameters.videoPath;//"partstown.flv"; myVideo.skin = this.loaderInfo.parameters.skinPath;//"SkinUnderPlayStopSeekMuteVol.swf" myVideo.skinBackgroundColor = 0xAEBEFB; myVideo.skinBackgroundAlpha = 0.5; myVideo.width = 939; myVideo.height = 660; myVideo.addEventListener(VideoEvent.COMPLETE, completePlay); function completePlay(e:VideoEvent):void { myVideo.alpha=0.2; ExternalInterface.call(theScript); } addChild(myVideo); Why would the listener be triggered before the event complete? How can I fix it? Thanks!

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• How to remove FacesMessages from the FacesContext?

  - by gurupriyan.e

  In my screen, I have a drop down(select box), on selection of any of the options in that drop down , i display one or more text boxes beside the select box using javascript/css - display:none and display:block. All these input controls are in the same jsf form. Each of the input controls have their own validator. The problem is suppose the user selects from selection box and doesn't input value or inputs a wrong value for , i add a custom FacesMessage in the Validator and is shown appropriately and suppose the user selects the the second time and inputs the wrong value for the then another FacesMessage is added in the validator. But Now both the Messages are shown - means - the message for and - which is wrong My assumption is that , this happens because they exist in the same form and their instances are not destroyed yet in the FacesContext and in the UIView. I decided to delete the messages this way Iterator<FacesMessage> msgIterator = FacesContext.getCurrentInstance().getMessages(); while(msgIterator.hasNext()) { msgIterator.next(); msgIterator.remove(); } But this sometimes gives java.util.NoSuchElementException org.apache.myfaces.shared_impl.renderkit.html.HtmlMessagesRendererBase$MessagesIterator.next So 2 questions : 1) What is the problem in deleting the FacesMessages this way? I am using myfaces-api-1.2.3.jar and myfaces-impl-1.2.3.jar 2) Is there a better approach to handle my scenario? I only want to show relevent messages every time a jsf request is processed Thanks

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• Biztalk Server 2009 - Failover Clustering and Network Load Balancing (NLB)

  - by FullOfQuestions

  Hi, We are planning a Biztalk 2009 set up in which we have 2 Biztalk Application Servers and 2 DB Servers (DB servers being in an Active/Passive Cluster). All servers are running Windows Server 2008 R2. As part of our application, we will have incoming traffic via the MSMQ, FILE and SOAP adapters. We also have a requirement for High-availability and Load-balancing. Let's say I create two different Biztalk Hosts and assign the FILE receive handler to the first one and the MSMQ receive handler to the second one. I now create two host instances for each of the two hosts (i.e. one for each of my two physical servers). After reviewing the Biztalk Documentation, this is what I know so far: For FILE (Receive), high-availablity and load-balancing will be achieved by Biztalk automatically because I set up a host instance on each of the two servers in the group. MSMQ (Receive) requires Biztalk Host Clustering to ensure high-availability (Host Clustering however requires Windows Failover Clustering to be set up as well). No loading-balancing option is clear here. SOAP (Receive) requires NLB to achieve Load-balancing and High-availability (if one server goes down, NLB will direct traffic to the other). This is where I'm completely puzzled and I desperately need your help: Is it possible to have a Windows Failover Cluster and NLB set up at the same time on the two application servers? If yes, then please tell me how. If no, then please explain to me how anyone is acheiving high-availability and load-balancing for MSMQ and SOAP when their underlying prerequisites are mutually exclusive! Your help is greatly appreciated, M

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• SharePoint: Can't Connect to a Configuration Database When Using Configuration Wizard

  - by Denis

  Hello everyone. I wonder if you could help me with the following problem: We have a SharePoint farm consisted of two servers with an NLB (a load balancer), a database server and an index server (4 servers in total). The issues initially appeared when we were trying to change Search settings via Shared services provider and an error was appearing with the message I can’t even remember now. To fix that problem, we decided to restart Search services on the Index server via Central Administration… and the process had stuck with a status “stopping” for several days. We’ve found a few solutions on the forums, but nothing had helped. Then we’ve tried to exclude the Index server from the farm, but yet again, Search services would not stop. However, after a week we’ve noticed that the services finally stopped. That was a prologue. So, after the Search services have finally stopped, we decided to return the Index server back to the farm via the SharePoint Configuration wizard. When we click on a button “Search database instances” (don’t know the exact name in English, we have a Russian version), a correct database name and user are automatically appear in the relevant fields. Then we supply a password for the user and click “next” two times and the configuration begins. Unfortunately, at the second stage we receive the error “Could not connect to a configuration database” with the exception in the log file: “Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.” Now we can’t figure out why the configuration wizard can’t connect to the configuration database. Any suggestions will be really appreciated.

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• Silverlight 4. Activator.CreateInstance uses a huge amount of memory

  - by Marco

  Hi, I have been playing a bit with Silverlight and try to port my Silverlight 3.0 application to Silverlight 4.0. My application loads different XAP files and upon a user request create an instance of a Xaml user control and adds it to the main container, in a sort of MEF approach in order I can have an extensible and pluggable application. The application is pretty huge and to keep acceptable the performances and the initial loading I have built up some helper classes to load in the background all pages and user controls that might be used later on. On Silverlight 3.0 everything was running smoothly without any problem so far. Switching to SL 4.0 I have noticed that when the process approaches to create the instances of the user controls using Activator.CreateInstance, the layout freezes unexpectedly for a minute and sometimes for more. Looking at the task manager the memory usage of IE jumps from 50MB to 400MB and sometimes to 1.5 GB. If the process won't take that much the layout is rendered properly and the memory falls back to 50 MB. Otherwise everything crashes due to out of memory exeption. Does anybody encountered the same problem? Or has anybody a solution about this tricky issue? Thans in advance Marco

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• Synchronizing Asynchronous request handlers in Silverlight environment

  - by Eric Lifka

  For our senior design project my group is making a Silverlight application that utilizes graph theory concepts and stores the data in a database on the back end. We have a situation where we add a link between two nodes in the graph and upon doing so we run analysis to re-categorize our clusters of nodes. The problem is that this re-categorization is quite complex and involves multiple queries and updates to the database so if multiple instances of it run at once it quickly garbles data and breaks (by trying to re-insert already used primary keys). Essentially it's not thread safe, and we're trying to make it safe, and that's where we're failing and need help :). The create link function looks like this: private Semaphore dblock = new Semaphore(1, 1); // This function is on our service reference and gets called // by the client code. public int addNeed(int nodeOne, int nodeTwo) { dblock.WaitOne(); submitNewNeed(createNewNeed(nodeOne, nodeTwo)); verifyClusters(nodeOne, nodeTwo); dblock.Release(); return 0; } private void verifyClusters(int nodeOne, int nodeTwo) { // Run analysis of nodeOne and nodeTwo in graph } All copies of addNeed should wait for the first one that comes in to finish before another can execute. But instead they all seem to be running and conflicting with each other in the verifyClusters method. One solution would be to force our front end calls to be made synchronously. And in fact, when we do that everything works fine, so the code logic isn't broken. But when it's launched our application will be deployed within a business setting and used by internal IT staff (or at least that's the plan) so we'll have the same problem. We can't force all clients to submit data at different times, so we really need to get it synchronized on the back end. Thanks for any help you can give, I'd be glad to supply any additional information that you could need!

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• Wicket: stateless AJAX behaviors in stateful page without serialization

  - by mschayna

  I have pretty stateful page with plenty of AJAX components. Most of these components have behaviors, which renders JavaScript code for calling AJAX requests to Java code. Because page isn't stateless, each request causes serialization of page. So far so good. But some of these AJAX requests doesn't change page ever, so serialization of page isn't necessary. For example it is forward caching data for (home-brewed) datagrid component. These requests are calling continuously and serialization of page during each request causes delays. There are some projects for stateless wicket components out there, e.g. wicket-stateless, but it solves another situation -- request of stateless components are processed on new instances of stateless pages. I want to process requests on existing stateful page instance but without serialization. I have tried to implement this in my own RequestCycleProcessor.resolve(), but I hung on searching for page from requestParameters because Session.getPage() always touches page and it causes serialization after request processing. Is there any example, idea, whatever for implementing this in Wicket? Hope it's understandable :)

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