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  • SQL SERVER – Difference Between CURRENT_TIMESTAMP and GETDATE() – CURRENT_TIMESTAMP Equivalent in SQL Server

    - by pinaldave
    A common question – I often get from Oracle/MySQL Professionals: “What is the Equivalent to CURRENT_TIMESTAMP in SQL Server?” Here is a common question I often get from SQL Server Professionals: “What are differences between Difference Between CURRENT_TIMESTAMP and GETDATE ()?” Very simple question but have showed up so frequently that I feel like to write about it. Well in SQL Server GETDATE() is Equivalent to CURRENT_TIMESTAMP. However, if you use CURRENT_TIMESTAMP in your select statement it will work fine. You can see in the above example – both of them returns the same value. Now let us go to next question regarding difference between GETDATE and CURRENT_TIMESTAMP. Well, the matter of the fact, there is no difference between them in SQL Server (Reference Link). CURRENT_TIMESTAMP is an ANSI SQL function, whereas GETDATE is T-SQL implementation of the same function. Both of them derive value from the operating system of the computer on which SQL Server instance is running. Above discussion prompts another question – in this case, what should one use GETDATE or CURRENT_TIMESTAMP? Well, this is indeed tricky and interesting question. I think I am very comfortable using the GETDATE () so I will go to use it but a matter of the fact there is no right or wrong answer. If you want to follow ancient saying “When in Rome, do as the Romans do”, I suggest using the GETDATE (), or continue using CURRENT_TIMESTAMP. With that said, there is one very important property we all need to keep in mind. If you use CURRENT_TIMESTAMP while creating an object, they are automatically converted to GETDATE() and stored internally. To illustrate what I am suggesting here is the example - Create a table using the following script CREATE TABLE [dbo].[TestTable]( [Cold2] [datetime] NULL ) ON [PRIMARY] GO ALTER TABLE [dbo].[TestTable] ADD DEFAULT (CURRENT_TIMESTAMP) FOR [Cold2] GO Now go to SSMS and generate the script for the table and you will notice following syntax. CREATE TABLE [dbo].[TestTable]( [Cold2] [datetime] NULL ) ON [PRIMARY] GO ALTER TABLE [dbo].[TestTable] ADD DEFAULT (GETDATE()) FOR [Cold2] GO You can notice that SQL Server have automatically converted CURRENT_TIMESTAMP to GETDATE(). I guess this gives us an idea how they behave. Now go ahead and make your choice! Do let me know which one will you use CURRENT_TIMESTAMP or GETDATE () in the comments area. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DateTime, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Using set operation in LINQ

    - by vik20000in
    There are many set operation that are required to be performed while working with any kind of data. This can be done very easily with the help of LINQ methods available for this functionality. Below are some of the examples of the set operation with LINQ. Finding distinct values in the set of data. We can use the distinct method to find out distinct values in a given list.     int[] factorsOf300 = { 2, 2, 3, 5, 5 };     var uniqueFactors = factorsOf300.Distinct(); We can also use the set operation of UNION with the help of UNION method in the LINQ. The Union method takes another collection as a parameter and returns the distinct union values in  both the list. Below is an example.     int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };    int[] numbersB = { 1, 3, 5, 7, 8 };    var uniqueNumbers = numbersA.Union(numbersB); We can also get the set operation of INTERSECT with the help of the INTERSECT method. Below is an example.     int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };     int[] numbersB = { 1, 3, 5, 7, 8 };         var commonNumbers = numbersA.Intersect(numbersB);  We can also find the difference between the 2 sets of data with the help of except method.      int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };     int[] numbersB = { 1, 3, 5, 7, 8 };         IEnumerable<int> aOnlyNumbers = numbersA.Except(numbersB);  Vikram

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  • Silverlight Cream for November 26, 2011 -- #1175

    - by Dave Campbell
    In this Issue: Michael Washington, Manas Patnaik, Jeff Blankenburg, Doug Mair, Jon Galloway, Richard Bartholomew, Peter Bromberg, Joel Reyes, Zeben Chen, Navneet Gupta, and Cathy Sullivan. Above the Fold: Silverlight: "Using ASP.NET PageMethods With Silverlight" Peter Bromberg WP7: "Leveraging Background Services and Agents in Windows Phone 7 (Mango)" Jon Galloway Metro/WinRT/Windows8: "Debugging Contracts using Windows Simulator" Cathy Sullivan LightSwitch: "LightSwitch: It Is About The Money (It Is Always About The Money)" Michael Washington Shoutouts: Michael Palermo's latest Desert Mountain Developers is up Michael Washington's latest Visual Studio #LightSwitch Daily is up From SilverlightCream.com:LightSwitch: It Is About The Money (It Is Always About The Money)Michael Washington has a very nice post up about LightSwitch apps in general and his opinion about the future use... based on what he and I have been up to, I tend to agree on all counts!Accessing Controls from DataGrid ColumnHeader – SilverlightManas Patnaik's latest post is about using the VisualTreeHelper class to iterate through the visual tree to find the controls you need ... including sample code31 Days of Mango | Day #18: Using Sample DataJeff Blankenburg's Day 18 in his 31-Day Mango quest is on Sample Data using Expression Blend, and he begins with great links to his other Blend posts followed by a nice sample data tutorial and source31 Days of Mango | Day #19: Tilt EffectsDoug Mair returns to the reigns of Jeff's 31-Days series with number 19 which is all about Tilt Effects ... as seen in the Phone application when you select a user... Doug shows how to add this effect to your appLeveraging Background Services and Agents in Windows Phone 7 (Mango)Jon Galloway has a WP7 post up discussing Background Services and how they all fit together... he's got a great diagram of that as an overview then really nice discussion of each followed up by his slides from DevConnections, and codeNetflix on Windows 8This one isn't C#/XAML, but Richard Bartholomew has a Netflix on Windows 8 app running that bears noticeUsing ASP.NET PageMethods With SilverlightPeter Bromberg has a post up demonstrating calling PageMethods from a Silverlight app using the ScriptManager controlAWESOME Windows Phone Power ToolJoel Reyes announced the release of a full-featured tool for side-loading apps to your WP7 device... available at codeplexMicrosoft Windows Simulator Rotation and Resolution EmulationZeben Chen discusses the Windows 8 Simulator a bit deeper with this code-laden post showing how to look at roation and orientation-aware apps and resolution.First look at Windows SimulatorNavneet Gupta has a great into post to using the simulator in VS2011 for Windows 8 apps. Four things you really need this for: Touch Emulation, Rotation, Different target resolutions, and ContractsDebugging Contracts using Windows SimulatorCathy Sullivan shows how to debug W8 Contracts in VS2011... why you ask? because when you hit one in the debugger, the target app disappears.. but enter the simulator... check it outStay in the 'Light!Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCreamJoin me @ SilverlightCream | Phoenix Silverlight User GroupTechnorati Tags:Silverlight    Silverlight 3    Silverlight 4    Windows PhoneMIX10

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  • Asynchronous connectToServer

    - by Pavel Bucek
    Users of JSR-356 – Java API for WebSocket are probably familiar with WebSocketContainer#connectToServer method. This article will be about its usage and improvement which was introduce in recent Tyrus release. WebSocketContainer#connectToServer does what is says, it connects to WebSocketServerEndpoint deployed on some compliant container. It has two or three parameters (depends on which representation of client endpoint are you providing) and returns aSession. Returned Session represents WebSocket connection and you are instantly able to send messages, register MessageHandlers, etc. An issue might appear when you are trying to create responsive user interface and use this method – its execution blocks until Session is created which usually means some container needs to be started, DNS queried, connection created (it’s even more complicated when there is some proxy on the way), etc., so nothing which might be really considered as responsive. Trivial and correct solution is to do this in another thread and monitor the result, but.. why should users do that? :-) Tyrus now provides async* versions of all connectToServer methods, which performs only simple (=fast) check in the same thread and then fires a new one and performs all other tasks there. Return type of these methods is Future<Session>. List of added methods: public Future<Session> asyncConnectToServer(Class<?> annotatedEndpointClass, URI path) public Future<Session> asyncConnectToServer(Class<? extends Endpoint>  endpointClass, ClientEndpointConfig cec, URI path) public Future<Session> asyncConnectToServer(Endpoint endpointInstance, ClientEndpointConfig cec, URI path) public Future<Session> asyncConnectToServer(Object obj, URI path) As you can see, all connectToServer variants have its async* alternative. All these methods do throw DeploymentException, same as synchronous variants, but some of these errors cannot be thrown as a result of the first method call, so you might get it as the cause ofExecutionException thrown when Future<Session>.get() is called. Please let us know if you find these newly added methods useful or if you would like to change something (signature, functionality, …) – you can send us a comment to [email protected] or ping me personally. Related links: https://tyrus.java.net https://java.net/jira/browse/TYRUS/ https://github.com/tyrus-project/tyrus

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  • SQL SERVER – Simple Explanation and Puzzle with SOUNDEX Function and DIFFERENCE Function

    - by pinaldave
    Earlier this week I asked a question where I asked how to Swap Values of the column without using CASE Statement. Read here: A Puzzle – Swap Value of Column Without Case Statement,there were more than 50 solutions proposed in the comment. There were many creative solutions. I have mentioned my personal favorite (different ones) here: Solution of Puzzle – Swap Value of Column Without Case Statement. However, I received lots of questions regarding one of the Solution by SIJIN KUMAR V P. He has used the function SOUNDEX in his solution. The request was to explain how SOUNDEX and DIFFERENCE works. Well, there are pretty decent documentations provided over here SOUNDEX function and DIFFERENCE over on MSDN and if I attempt to explain this function I will end up writing the same details which are available on MSDN. Instead of writing theory, we will try to learn this function by using a couple of simple puzzles. You try to solve the puzzles using the MSDN and see if you can learn something very quickly. In simple words - SOUNDEX converts an alphanumeric string to a four-character code to find similar-sounding words or names. The first character of the code is the first character of character_expression and the second through fourth characters of the code are numbers that represent the letters in the expression. Vowels incharacter_expression are ignored unless they are the first letter of the string. DIFFERENCE function returns an integer value. The  integer returned is the number of characters in the SOUNDEX values that are the same. The return value ranges from 0 through 4: 0 indicates weak or no similarity, and 4 indicates strong similarity or the same values. Learning Puzzle 1: Now let us run following four queries and observe its output. SELECT SOUNDEX('SQLAuthority') SdxValue SELECT SOUNDEX('SLTR') SdxValue SELECT SOUNDEX('SaLaTaRa') SdxValue SELECT SOUNDEX('SaLaTaRaM') SdxValue When you look at the result set all the four values are same. The reason for all the values to be same is as for SQL Server SOUNDEX function all the four strings are similarly sounding string. Learning Puzzle 2: Now let us run following five queries and observe its output. SELECT DIFFERENCE (SOUNDEX('SLTR'),SOUNDEX('SQLAuthority')) SELECT DIFFERENCE (SOUNDEX('TH'),SOUNDEX('SQLAuthority')) SELECT DIFFERENCE ('SQLAuthority',SOUNDEX('SQLAuthority')) SELECT DIFFERENCE ('SLTR',SOUNDEX('SQLAuthority')) SELECT DIFFERENCE ('SLTR','SQLAuthority') When you look at the result set you will get the result in the ranges from 1 to 4. Here is how it works if your result is 0 which means absolutely not relevant to each other and if your result is 1 which means the results are relevant to each other. Have you ever used above two functions in your business need or on production server? If yes, would you please leave a comment with use cases. I believe it will be beneficial to everyone. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • PTLQueue : a scalable bounded-capacity MPMC queue

    - by Dave
    Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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  • JavaScript in different browsers

    - by PointsToShare
    Adventures with JavaScript rendered in IE 8, Chrome 15, and Firefox 8.0 I have written a little monogram about the advantages of Math and wrote a few JavaScript applications to demonstrate them. I was a bit careless and used elements on the page in my JavaScript without using any of the GetElementsByXXXX methods to identify them.  Say I had a text box named tbSeqNum into which I entered a number to be used in a computation. In my code I simply referred to its value by using it directly. Like here: Function Blah() {                 return tbSeqNum.value; } This ran fine in IE8. In IE, the elements are available as global variables. This is not the case in either Firefox or Chrome. In there one has to create the variable and only then use it. Assuming I also used tbSeqNum as the element’s ID, this works: Function Blah() {                 return GetElementById(“tbSeqNum”).value; } Naturally this corrected function also works in IE, so be warned. Also, coming from windows programming (I am long in the tooth and programmed long before the internet), I have a habit of putting an “Exit” button on my pages and setting their onclick to: onclick=”window.close()”. Again, this works fine in IE. In Firefox and chrome, it does not! There you can only close a window that you opened in the code. A window that was opened by navigation to a URL will not close.  Before I deployed mu code to my website, I painfully removed all my Exit buttons. But my greatest surprise came when I tested my pages in the various browsers. In my code I do a comparison on the performance of two algorithms used to solve the same problem. One is brute force, the other uses a mathematical formula. The compare functions runs each many times and displays the time it took for each and also the ratio. Chrome runs JavaScript between 5 and 10 times faster than Firefox and between 50 and 100 times faster that IE. Wow!!! This difference is especially remarkable when the code uses iteration. I suspect that the JS engines in Chrome and Firefox simply cache the result of a function and if it is called again with the same parameters, it returns the cached result. To see it in action play run the “How Many Squares” page in www.mgsltns.com/games.htm The host is running on Unix, so the link is case sensitive. Last Note: IE9 runs JS a bit faster, but still lags behind almost as badly. That’s All Folks!

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  • OpenGL - have object follow mouse

    - by kevin james
    I want to have an object follow around my mouse on the screen in OpenGL. (I am also using GLEW, GLFW, and GLM). The best idea I've come up with is: Get the coordinates within the window with glfwGetCursorPos. The window was created with window = glfwCreateWindow( 1024, 768, "Test", NULL, NULL); and the code to get coordinates is double xpos, ypos; glfwGetCursorPos(window, &xpos, &ypos); Next, I use GLM unproject, to get the coordinates in "object space" glm::vec4 viewport = glm::vec4(0.0f, 0.0f, 1024.0f, 768.0f); glm::vec3 pos = glm::vec3(xpos, ypos, 0.0f); glm::vec3 un = glm::unProject(pos, View*Model, Projection, viewport); There are two potential problems I can already see. The viewport is fine, as the initial x,y, coordinates of the lower left are indeed 0,0, and it's indeed a 1024*768 window. However, the position vector I create doesn't seem right. The Z coordinate should probably not be zero. However, glfwGetCursorPos returns 2D coordinates, and I don't know how to go from there to the 3D window coordinates, especially since I am not sure what the 3rd dimension of the window coordinates even means (since computer screens are 2D). Then, I am not sure if I am using unproject correctly. Assume the View, Model, Projection matrices are all OK. If I passed in the correct position vector in Window coordinates, does the unproject call give me the coordinates in Object coordinates? I think it does, but the documentation is not clear. Finally, to each vertex of the object I want to follow the mouse around, I just increment the x coordinate by un[0], the y coordinate by -un[1], and the z coordinate by un[2]. However, since my position vector that is being unprojected is likely wrong, this is not giving good results; the object does move as my mouse moves, but it is offset quite a bit (i.e. moving the mouse a lot doesn't move the object that much, and the z coordinate is very large). I actually found that the z coordinate un[2] is always the same value no matter where my mouse is, probably because the position vector I pass into unproject always has a value of 0.0 for z. Edit: The (incorrectly) unprojected x-values range from about -0.552 to 0.552, and the y-values from about -0.411 to 0.411.

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  • AI for a mixed Turn Based + Real Time battle system - Something "Gambit like" the right approach?

    - by Jason L.
    This is maybe a question that's been asked 100 times 1,000 different ways. I apologize for that :) I'm in the process of building the AI for a game I'm working on. The game is a turn based one, in the vein of Final Fantasy but also has a set of things that happen in real time (reactions). I've experimented with FSM, HFSMs, and Behavior Trees. None of them felt "right" to me and all felt either too limiting or too generic / big. The idea I'm toying with now is something like a "Rules engine" that could be likened to the Gambit system from Final Fantasy 12. I would have a set of predefined personalities. Each of these personalities would have a set of conditions it would check on each event (Turn start, time to react, etc). These conditions would be priority ordered, and the first one that returns true would be the action I take. These conditions can also point to a "choice" action, which is just an action that will make a choice based on some Utility function. Sort of a mix of FSM/HFSM and a Utility Function approach. So, a "gambit" with the personality of "Healer" may look something like this: (ON) Ally HP = 0% - Choose "Relife" spell (ON) Ally HP < 50% - Choose Heal spell (ON) Self HP < 65% - Choose Heal spell (ON) Ally Debuff - Choose Debuff Removal spell (ON) Ally Lost Buff - Choose Buff spell Likewise, a "gambit" with the personality of "Agressor" may look like this: (ON) Foe HP < 10% - Choose Attack skill (ON) Foe any - Choose target - Choose Attack skill (ON) Self Lost Buff - Choose Buff spell (ON) Foe HP = 0% - Taunt the player What I like about this approach is it makes sense in my head. It also would be extremely easy to build an "AI Editor" with an approach like this. What I'm worried about is.. would it be too limiting? Would it maybe get too complicated? Does anyone have any experience with AIs in Turn Based games that could maybe provide me some insight into this approach.. or suggest a different approach? Many thanks in advance!!!

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  • Finding the XPath with the node name

    - by julien.schneider(at)oracle.com
    A function that i find missing is to get the Xpath expression of a node. For example, suppose i only know the node name <theNode>, i'd like to get its complete path /Where/is/theNode.   Using this rather simple Xquery you can easily get the path to your node. declare namespace orcl = "http://www.oracle.com/weblogic_soa_and_more"; declare function orcl:findXpath($path as element()*) as xs:string { if(local-name($path/..)='') then local-name($path) else concat(orcl:findXpath($path/..),'/',local-name($path)) }; declare function orcl:PathFinder($inputRecord as element(), $path as element()) as element(*) { { for $index in $inputRecord//*[local-name()=$path/text()] return orcl:findXpath($index) } }; declare variable $inputRecord as element() external; declare variable $path as element() external; orcl:PathFinder($inputRecord, $path)   With a path         <myNode>nodeName</myNode>  and a message         <node1><node2><nodeName>test</nodeName></node2></node1>  the result will be         node1/node2/nodeName   This is particularly useful when you use the Validate action of OSB because Validate only returns the xml node which is in error and not the full location itself. The following OSB project reuses this Xquery to reformat the result of the Validate Action. Just send an invalid xml like <myElem http://blogs.oracle.com/weblogic_soa_and_more"http://blogs.oracle.com/weblogic_soa_and_more">      <mySubElem>      </mySubElem></myElem>   you'll get as nice <MessageIsNotValid> <ErrorDetail  nbr="1"> <dataElementhPath>Body/myElem/mySubElem</dataElementhPath> <message> Expected element 'Subelem1@http://blogs.oracle.com/weblogic_soa_and_more' before the end of the content in element mySubElem@http://blogs.oracle.com/weblogic_soa_and_more </message> </ErrorDetail> </MessageIsNotValid>   Download the OSB project : sbconfig_xpath.jar   Enjoy.            

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  • iOS - pass UIImage to shader as texture

    - by martin pilch
    I am trying to pass UIImage to GLSL shader. The fragment shader is: varying highp vec2 textureCoordinate; uniform sampler2D inputImageTexture; uniform sampler2D inputImageTexture2; void main() { highp vec4 color = texture2D(inputImageTexture, textureCoordinate); highp vec4 color2 = texture2D(inputImageTexture2, textureCoordinate); gl_FragColor = color * color2; } What I want to do is send images from camera and do multiply blend with texture. When I just send data from camera, everything is fine. So problem should be with sending another texture to shader. I am doing it this way: - (void)setTexture:(UIImage*)image forUniform:(NSString*)uniform { CGSize sizeOfImage = [image size]; CGFloat scaleOfImage = [image scale]; CGSize pixelSizeOfImage = CGSizeMake(scaleOfImage * sizeOfImage.width, scaleOfImage * sizeOfImage.height); //create context GLubyte * spriteData = (GLubyte *)malloc(pixelSizeOfImage.width * pixelSizeOfImage.height * 4 * sizeof(GLubyte)); CGContextRef spriteContext = CGBitmapContextCreate(spriteData, pixelSizeOfImage.width, pixelSizeOfImage.height, 8, pixelSizeOfImage.width * 4, CGImageGetColorSpace(image.CGImage), kCGImageAlphaPremultipliedLast); //draw image into context CGContextDrawImage(spriteContext, CGRectMake(0.0, 0.0, pixelSizeOfImage.width, pixelSizeOfImage.height), image.CGImage); //get uniform of texture GLuint uniformIndex = glGetUniformLocation(__programPointer, [uniform UTF8String]); //generate texture GLuint textureIndex; glGenTextures(1, &textureIndex); glBindTexture(GL_TEXTURE_2D, textureIndex); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); //create texture glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, pixelSizeOfImage.width, pixelSizeOfImage.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, spriteData); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, textureIndex); //"send" to shader glUniform1i(uniformIndex, 1); free(spriteData); CGContextRelease(spriteContext); } Uniform for texture is fine, glGetUniformLocation function do not returns -1. The texture is PNG file of resolution 2000x2000 pixels. PROBLEM: When the texture is passed to shader, I have got "black screen". Maybe problem are parameters of the CGContext or parameters of the function glTexImage2D Thank you

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  • PHP MVC error handling, view display and user permissions

    - by cen
    I am building a moderation panel from scratch in a MVC approach and a lot of questions cropped up during development. I would like to hear from others how they handle these situations. Error handling Should you handle an error inside the class method or should the method return something anyway and you handle the error in controller? What about PDO exceptions, how to handle them? For example, let's say we have a method that returns true if the user exists in a table and false if he does not exist. What do you return in the catch statement? You can't just return false because then the controller assumes that everything is alright while the truth is that something must be seriously broken. Displaying the error from the method completely breaks the whole design. Maybe a page redirect inside the method? The proper way to show a view The controller right now looks something like this: include('view/header.php'); if ($_GET['m']=='something') include('view/something.php'); elseif ($_GET['m']=='somethingelse') include('view/somethingelse.php'); include('view/foter.php'); Each view also checks if it was included from the index page to prevent it being accessed directly. There is a view file for each different document body. Is this way of including different views ok or is there a more proper way? Managing user rights Each user has his own rights, what he can see and what he can do. Which part of the system should verify that user has the permission to see the view, controller or view itself? Right now I do permission checks directly in the view because each view can contain several forms that require different permissions and I would need to make a seperate file for each of them if it was put in the controller. I also have to re-check for the permissions everytime a form is submitted because form data can be easily forged. The truth is, all this permission checking and validating the inputs just turns the controller into a huge if/then/else cluster. I feel like 90% of the time I am doing error checks/permissions/validations and very little of the actual logic. Is this normal even for popular frameworks?

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  • Twitte API for Java - Hello Twitter Servlet (TOTD #178)

    - by arungupta
    There are a few Twitter APIs for Java that allow you to integrate Twitter functionality in a Java application. This is yet another API, built using JAX-RS and Jersey stack. I started this effort earlier this year and kept delaying to share because wanted to provide a more comprehensive API. But I've delayed enough and releasing it as a work-in-progress. I'm happy to take contributions in order to evolve this API and make it complete, useful, and robust. Drop a comment on the blog if you are interested or ping me at @arungupta. How do you get started ? Just add the following to your "pom.xml": <dependency> <groupId>org.glassfish.samples</groupId> <artifactId>twitter-api</artifactId> <version>1.0-SNAPSHOT</version></dependency> The implementation of this API uses Jersey OAuth Filters for authentication with Twitter and so the following dependencies are required if any API that requires authentication, which is pretty much all the APIs ;-) <dependency> <groupId>com.sun.jersey.contribs.jersey-oauth</groupId>     <artifactId>oauth-client</artifactId>     <version>${jersey.version}</version> </dependency> <dependency>     <groupId>com.sun.jersey.contribs.jersey-oauth</groupId>     <artifactId>oauth-signature</artifactId>     <version>${jersey.version}</version> </dependency> Once the dependencies are added to your project, inject Twitter  API in your Servlet (or any other Java EE component) as: @Inject Twitter twitter; Here is a simple non-secure invocation of the API to get you started: SearchResults result = twitter.search("glassfish", SearchResults.class);for (SearchResultsTweet t : result.getResults()) { out.println(t.getText() + "<br/>");} This code returns the tweets that matches the query "glassfish". The source code for the complete project can be downloaded here. Download it, unzip, and mvn package will build the .war file. And then deploy it on GlassFish or any other Java EE 6 compliant application server! The source code for the API also acts as the javadocs and can be checked out from here. A more detailed sample using security and several other API from this library is coming soon!

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  • AWS .NET SDK v2: the message-pump pattern

    - by Elton Stoneman
    Originally posted on: http://geekswithblogs.net/EltonStoneman/archive/2013/10/11/aws-.net-sdk-v2--the-message-pump-pattern.aspxVersion 2 of the AWS SDK for .NET has had a few pre-release iterations on NuGet and is stable, if a bit lacking in step-by-step guides. There’s at least one big reason to try it out: the SQS queue client now supports asynchronous reads, so you don’t need a clumsy polling mechanism to retrieve messages. The new approach  is easy to use, and lets you work with AWS queues in a similar way to the message-pump pattern used in the latest Azure SDK for Service Bus queues and topics. I’ve posted a simple wrapper class for subscribing to an SQS hub on gist here: A wrapper for the SQS client in the AWS SDK for.NET v2, which uses the message-pump pattern. Here’s the core functionality in the subscribe method: private async void Subscribe() { if (_isListening) { var request = new ReceiveMessageRequest { MaxNumberOfMessages = 10 }; request.QueueUrl = QueueUrl; var result = await _sqsClient.ReceiveMessageAsync(request, _cancellationTokenSource.Token); if (result.Messages.Count > 0) { foreach (var message in result.Messages) { if (_receiveAction != null && message != null) { _receiveAction(message.Body); DeleteMessage(message.ReceiptHandle); } } } } if (_isListening) { Subscribe(); } } which you call with something like this: client.Subscribe(x=>Log.Debug(x.Body)); The async SDK call returns when there is something in the queue, and will run your receive action for every message it gets in the batch (defaults to the maximum size of 10 messages per call). The listener will sit there awaiting messages until you stop it with: client.Unsubscribe(); Internally it has a cancellation token which it sets when you call unsubscribe, which cancels any in-flight call to SQS and stops the pump. The wrapper will also create the queue if it doesn’t exist at runtime. The Ensure() method gets called in the constructor so when you first use the client for a queue (sending or subscribing), it will set itself up: if (!Exists()) { var request = new CreateQueueRequest(); request.QueueName = QueueName; var response = _sqsClient.CreateQueue(request); QueueUrl = response.QueueUrl; } The Exists() check has to do make a call to ListQueues on the SNS client, as it doesn’t provide its own method to check if a queue exists. That call also populates the Amazon Resource Name, the unique identifier for this queue, which will be useful later. To use the wrapper, just instantiate and go: var queueClient = new QueueClient(“ProcessWorkflow”); queueClient.Subscribe(x=>Log.Debug(x.Body)); var message = {}; //etc. queueClient.Send(message);

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  • SSAS: Utility to check you have the correct data types and sizes in your cube definition

    - by DrJohn
    This blog describes a tool I developed which allows you to compare the data types and data sizes found in the cube’s data source view with the data types/sizes of the corresponding dimensional attribute.  Why is this important?  Well when creating named queries in a cube’s data source view, it is often necessary to use the SQL CAST or CONVERT operation to change the data type to something more appropriate for SSAS.  This is particularly important when your cube is based on an Oracle data source or using custom SQL queries rather than views in the relational database.   The problem with BIDS is that if you change the underlying SQL query, then the size of the data type in the dimension does not update automatically.  This then causes problems during deployment whereby processing the dimension fails because the data in the relational database is wider than that allowed by the dimensional attribute. In particular, if you use some string manipulation functions provided by SQL Server or Oracle in your queries, you may find that the 10 character string you expect suddenly turns into an 8,000 character monster.  For example, the SQL Server function REPLACE returns column with a width of 8,000 characters.  So if you use this function in the named query in your DSV, you will get a column width of 8,000 characters.  Although the Oracle REPLACE function is far more intelligent, the generated column size could still be way bigger than the maximum length of the data actually in the field. Now this may not be a problem when prototyping, but in your production cubes you really should clean up this kind of thing as these massive strings will add to processing times and storage space. Similarly, you do not want to forget to change the size of the dimension attribute if your database columns increase in size. Introducing CheckCubeDataTypes Utiltity The CheckCubeDataTypes application extracts all the data types and data sizes for all attributes in the cube and compares them to the data types and data sizes in the cube’s data source view.  It then generates an Excel CSV file which contains all this metadata along with a flag indicating if there is a mismatch between the DSV and the dimensional attribute.  Note that the app not only checks all the attribute keys but also the name and value columns for each attribute. Another benefit of having the metadata held in a CSV text file format is that you can place the file under source code control.  This allows you to compare the metadata of the previous cube release with your new release to highlight problems introduced by new development. You can download the C# source code from here: CheckCubeDataTypes.zip A typical example of the output Excel CSV file is shown below - note that the last column shows a data size mismatch by TRUE appearing in the column

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  • Framework 4 Features: User Propogation to the Database

    - by Anthony Shorten
    Once of the features I mentioned in a previous entry was the ability for Oracle Utilities Application Framework V4 to automatically propogate the end user to the database connection. This bears more explanation. In the past releases of the Oracle Utilities Application Framework, all database connections are pooled and shared within a channel of access. So for example, the online connections on the Business Application Server share a common pool of connections and the batch in a thread pool shares a seperate pool of connections. The connections are pooled for performance reasons (the most expensive part of a typical transaction is opening and closing connections so we save time by having them ready beforehand). The idea is that when a business function needs some SQL to be execute it takes a spare connection from the pool, executes the SQL and then returns the connection back to the pool for reuse. Unfortunelty to support the pool being started and ready before the transactions arrives means that you need to have a shared userid (as you dont know the users who need them beforehand). Therefore each connection uses the same database user to execute the SQL it needs. This is acceptable for executing transactions, generally but does not allow the DBA or other tools to ascertain which end user is actually running the transaction. In Oracle Utilities Application Framework V4, we now set the CLIENT_IDENTIFIER to the end userid (not the Login Id) when the connection is taken from the pool and used and reset it back to blank when returned to the pool. The CLIENT_IDENTIFIER is a feature that is present in the Oracle Database connection information. From a monitoring perspective, when a connection to the database is actively running SQL, the end user is now able to be determined by querying the CLIENT_IDENTIFIER on the session object within the database. This can be done in the DBA's favorite monitoring tool (even just some SQL on the v$session table is enough). This has other implications as well. Oracle sells a lot of other security addons to the database and so do third parties. If a site wants to have additional levels of security or auditing in the database then the CLIENT_IDENTIFIER, if supported, is now available to be recorded or used by those products to provide additional levels of security. This facility was one of the highly "nice to haves" that customers would ask us about so we now allow it to be used to allow finer grained monitoring and additional security facilities. Note: This facility is only available for customers using the Oracle Database versions of our products.

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  • I Choose iNada

    - by Mark Treadwell
    As a laptop and Kindle user, I have been looking at the usual cyclical Apple frenzy in the press with the same kind of amused tolerance I give my three-year-old son.  They never seem to learn, and they keep repeating the same things.  However when I ready articles like this, I am reminded that that is not always the case. I am a happy user of a monster-sized HP HDX laptop, HP touch screen all-in-one system, and multi-screen Dell desktops at home as well as a HP business laptop at work.  I have no iPod, iMac, iTouch or any other relationship with the company who wants to trademark the prefix “i”. I have not missed them. That is not to say that I have no technological gadgets.  I do.  They just do not dominate Every company wants to preserve their customer base, but Apple just does it too rigidly.  The buy-in necessary rubs me wrong.  When the fanboys scream about the next great iApple thing which will kill off another market segment (this time, the iPad will kill off laptops), the amused tolerance returns. From what I have seen, the iPad virtual keyboard is a poor substitute for an actual keyboard.  It was intended to let you get some kind of text into a device that is not really intended for keyboard input, but rather for touch manipulation of a designed interface.  I like the virtual keyboard on my LG Dare cell phone, but you will not catch me writing my next novel with it.  But, you hear, you can connect a real keyboard and get info from another computer.  That is when you realize that the iPad is not a true standalone device like a laptop.  You have to make more hardware purchases to get what you truly want.  It is an expensive accommodation to get you a different form of freedom. So if Apple made a product with me in mind, you can have it.  Everyone gets to make their own choice.  My choice is the iNada.

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  • Executing server validators first before OnClientClick Javascript confirm/alert

    - by kaushalparik27
    I got to answer a simple question over community forums. Consider this: Suppose you are developing a webpage with few input controls and a submit button. You have placed some server validator controls like RequiredFieldValidator to validate the inputs entered by the user. Once user fill-in all the details and try to submit the page via button click you want to alert/confirm the submission like "Are you sure to modify above details?". You will consider to use javascript on click of the button.Everything seems simple and you are almost done. BUT, when you run the page; you will see that Javascript alert/confirm box is executing first before server validators try to validate the input controls! Well, this is expected behaviour. BUT, this is not you want. Then? The simple answer is: Call Page_ClientValidate() in javascript where you are alerting the submission. Below is the javascript example:    <script type="text/javascript" language="javascript">        function ValidateAllValidationGroups() {            if (Page_ClientValidate()) {                return confirm("Are you sure to modify above details?");            }        }    </script>Page_ClientValidate() function tests for all server validators and return bool value depends on whether the page meets defined validation criteria or not. In above example, confirm alert will only popup up if Page_ClientValidate() returns true (if all validations satisfy). You can also specify ValidationGroup inside this function as Page_ClientValidate('ValidationGroup1') to only validate a specific group of validation in your page.        function ValidateSpecificValidationGroup() {            if (Page_ClientValidate('ValidationGroup1')) {                return confirm("Are you sure to modify above details?");            }        }I have attached a sample example with this post here demonstrating both above cases. Hope it helps./.

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  • How to shoot yourself in the foot (DO NOT Read in the office)

    - by TATWORTH
    Originally posted on: http://geekswithblogs.net/TATWORTH/archive/2013/06/21/how-to-shoot-yourself-in-the-foot-do-not-read.aspxLet me make it absolutely clear - the following is:merely collated by your Geek from http://www.codeproject.com/Lounge.aspx?msg=3917012#xx3917012xxvery, very very funny so you read it in the presence of others at your own riskso here is the list - you have been warned!C You shoot yourself in the foot.   C++ You accidently create a dozen instances of yourself and shoot them all in the foot. Providing emergency medical assistance is impossible since you can't tell which are bitwise copies and which are just pointing at others and saying "That's me, over there."   FORTRAN You shoot yourself in each toe, iteratively, until you run out of toes, then you read in the next foot and repeat. If you run out of bullets, you continue anyway because you have no exception-handling facility.   Modula-2 After realizing that you can't actually accomplish anything in this language, you shoot yourself in the head.   COBOL USEing a COLT 45 HANDGUN, AIM gun at LEG.FOOT, THEN place ARM.HAND.FINGER on HANDGUN.TRIGGER and SQUEEZE. THEN return HANDGUN to HOLSTER. CHECK whether shoelace needs to be retied.   Lisp You shoot yourself in the appendage which holds the gun with which you shoot yourself in the appendage which holds the gun with which you shoot yourself in the appendage which holds...   BASIC Shoot yourself in the foot with a water pistol. On big systems, continue until entire lower body is waterlogged.   Forth Foot yourself in the shoot.   APL You shoot yourself in the foot; then spend all day figuring out how to do it in fewer characters.   Pascal The compiler won't let you shoot yourself in the foot.   Snobol If you succeed, shoot yourself in the left foot. If you fail, shoot yourself in the right foot.   HyperTalk Put the first bullet of the gun into foot left of leg of you. Answer the result.   Prolog You tell your program you want to be shot in the foot. The program figures out how to do it, but the syntax doesn't allow it to explain.   370 JCL You send your foot down to MIS with a 4000-page document explaining how you want it to be shot. Three years later, your foot comes back deep-fried.   FORTRAN-77 You shoot yourself in each toe, iteratively, until you run out of toes, then you read in the next foot and repeat. If you run out of bullets, you continue anyway because you still can't do exception-processing.   Modula-2 (alternative) You perform a shooting on what might be currently a foot with what might be currently a bullet shot by what might currently be a gun.   BASIC (compiled) You shoot yourself in the foot with a BB using a SCUD missile launcher.   Visual Basic You'll really only appear to have shot yourself in the foot, but you'll have so much fun doing it that you won't care.   Forth (alternative) BULLET DUP3 * GUN LOAD FOOT AIM TRIGGER PULL BANG! EMIT DEAD IF DROP ROT THEN (This takes about five bytes of memory, executes in two to ten clock cycles on any processor and can be used to replace any existing function of the language as well as in any future words). (Welcome to bottom up programming - where you, too, can perform compiler pre-processing instead of writing code)   APL (alternative) You hear a gunshot and there's a hole in your foot, but you don't remember enough linear algebra to understand what happened. or @#&^$%&%^ foot   Pascal (alternative) Same as Modula-2 except that the bullet is not the right type for the gun and your hand is blown off.   Snobol (alternative) You grab your foot with your hand, then rewrite your hand to be a bullet. The act of shooting the original foot then changes your hand/bullet into yet another foot (a left foot).   Prolog (alternative) You attempt to shoot yourself in the foot, but the bullet, failing to find its mark, backtracks to the gun, which then explodes in your face.   COMAL You attempt to shoot yourself in the foot with a water pistol, but the bore is clogged, and the pressure build-up blows apart both the pistol and your hand. or draw_pistol aim_at_foot(left) pull_trigger hop(swearing)   Scheme As Lisp, but none of the other appendages are aware of this happening.   Algol You shoot yourself in the foot with a musket. The musket is aesthetically fascinating and the wound baffles the adolescent medic in the emergency room.   Ada If you are dumb enough to actually use this language, the United States Department of Defense will kidnap you, stand you up in front of a firing squad and tell the soldiers, "Shoot at the feet." or The Department of Defense shoots you in the foot after offering you a blindfold and a last cigarette. or After correctly packaging your foot, you attempt to concurrently load the gun, pull the trigger, scream and shoot yourself in the foot. When you try, however, you discover that your foot is of the wrong type. or After correctly packing your foot, you attempt to concurrently load the gun, pull the trigger, scream, and confidently aim at your foot knowing it is safe. However the cordite in the round does an Unchecked Conversion, fires and shoots you in the foot anyway.   Eiffel   You create a GUN object, two FOOT objects and a BULLET object. The GUN passes both the FOOT objects a reference to the BULLET. The FOOT objects increment their hole counts and forget about the BULLET. A little demon then drives a garbage truck over your feet and grabs the bullet (both of it) on the way. Smalltalk You spend so much time playing with the graphics and windowing system that your boss shoots you in the foot, takes away your workstation and makes you develop in COBOL on a character terminal. or You send the message shoot to gun, with selectors bullet and myFoot. A window pops up saying Gunpowder doesNotUnderstand: spark. After several fruitless hours spent browsing the methods for Trigger, FiringPin and IdealGas, you take the easy way out and create ShotFoot, a subclass of Foot with an additional instance variable bulletHole. Object Oriented Pascal You perform a shooting on what might currently be a foot with what might currently be a bullet fired from what might currently be a gun.   PL/I You consume all available system resources, including all the offline bullets. The Data Processing & Payroll Department doubles its size, triples its budget, acquires four new mainframes and drops the original one on your foot. Postscript foot bullets 6 locate loadgun aim gun shoot showpage or It takes the bullet ten minutes to travel from the gun to your foot, by which time you're long since gone out to lunch. The text comes out great, though.   PERL You stab yourself in the foot repeatedly with an incredibly large and very heavy Swiss Army knife. or You pick up the gun and begin to load it. The gun and your foot begin to grow to huge proportions and the world around you slows down, until the gun fires. It makes a tiny hole, which you don't feel. Assembly Language You crash the OS and overwrite the root disk. The system administrator arrives and shoots you in the foot. After a moment of contemplation, the administrator shoots himself in the foot and then hops around the room rabidly shooting at everyone in sight. or You try to shoot yourself in the foot only to discover you must first reinvent the gun, the bullet, and your foot.or The bullet travels to your foot instantly, but it took you three weeks to load the round and aim the gun.   BCPL You shoot yourself somewhere in the leg -- you can't get any finer resolution than that. Concurrent Euclid You shoot yourself in somebody else's foot.   Motif You spend days writing a UIL description of your foot, the trajectory, the bullet and the intricate scrollwork on the ivory handles of the gun. When you finally get around to pulling the trigger, the gun jams.   Powerbuilder While attempting to load the gun you discover that the LoadGun system function is buggy; as a work around you tape the bullet to the outside of the gun and unsuccessfully attempt to fire it with a nail. In frustration you club your foot with the butt of the gun and explain to your client that this approximates the functionality of shooting yourself in the foot and that the next version of Powerbuilder will fix it.   Standard ML By the time you get your code to typecheck, you're using a shoot to foot yourself in the gun.   MUMPS You shoot 583149 AK-47 teflon-tipped, hollow-point, armour-piercing bullets into even-numbered toes on odd-numbered feet of everyone in the building -- with one line of code. Three weeks later you shoot yourself in the head rather than try to modify that line.   Java You locate the Gun class, but discover that the Bullet class is abstract, so you extend it and write the missing part of the implementation. Then you implement the ShootAble interface for your foot, and recompile the Foot class. The interface lets the bullet call the doDamage method on the Foot, so the Foot can damage itself in the most effective way. Now you run the program, and call the doShoot method on the instance of the Gun class. First the Gun creates an instance of Bullet, which calls the doFire method on the Gun. The Gun calls the hit(Bullet) method on the Foot, and the instance of Bullet is passed to the Foot. But this causes an IllegalHitByBullet exception to be thrown, and you die.   Unix You shoot yourself in the foot or % ls foot.c foot.h foot.o toe.c toe.o % rm * .o rm: .o: No such file or directory % ls %   370 JCL (alternative) You shoot yourself in the head just thinking about it.   DOS JCL You first find the building you're in in the phone book, then find your office number in the corporate phone book. Then you have to write this down, then describe, in cubits, your exact location, in relation to the door (right hand side thereof). Then you need to write down the location of the gun (loading it is a proprietary utility), then you load it, and the COBOL program, and run them, and, with luck, it may be run tonight.   VMS   $ MOUNT/DENSITY=.45/LABEL=BULLET/MESSAGE="BYE" BULLET::BULLET$GUN SYS$BULLET $ SET GUN/LOAD/SAFETY=OFF/SIGHT=NONE/HAND=LEFT/CHAMBER=1/ACTION=AUTOMATIC/ LOG/ALL/FULL SYS$GUN_3$DUA3:[000000]GUN.GNU $ SHOOT/LOG/AUTO SYS$GUN SYS$SYSTEM:[FOOT]FOOT.FOOT   %DCL-W-ACTIMAGE, error activating image GUN -CLI-E-IMGNAME, image file $3$DUA240:[GUN]GUN.EXE;1 -IMGACT-F-NOTNATIVE, image is not an OpenVMS Alpha AXP image or %SYS-F-FTSHT, foot shot (fifty lines of traceback omitted) sh,csh, etc You can't remember the syntax for anything, so you spend five hours reading manual pages, then your foot falls asleep. You shoot the computer and switch to C.   Apple System 7 Double click the gun icon and a window giving a selection for guns, target areas, plus balloon help with medical remedies, and assorted sound effects. Click "shoot" button and a small bomb appears with note "Error of Type 1 has occurred."   Windows 3.1 Double click the gun icon and wait. Eventually a window opens giving a selection for guns, target areas, plus balloon help with medical remedies, and assorted sound effects. Click "shoot" button and a small box appears with note "Unable to open Shoot.dll, check that path is correct."   Windows 95 Your gun is not compatible with this OS and you must buy an upgrade and install it before you can continue. Then you will be informed that you don't have enough memory.   CP/M I remember when shooting yourself in the foot with a BB gun was a big deal.   DOS You finally found the gun, but can't locate the file with the foot for the life of you.   MSDOS You shoot yourself in the foot, but can unshoot yourself with add-on software.   Access You try to point the gun at your foot, but it shoots holes in all your Borland distribution diskettes instead.   Paradox Not only can you shoot yourself in the foot, your users can too.   dBase You squeeze the trigger, but the bullet moves so slowly that by the time your foot feels the pain, you've forgotten why you shot yourself anyway. or You buy a gun. Bullets are only available from another company and are promised to work so you buy them. Then you find out that the next version of the gun is the one scheduled to actually shoot bullets.   DBase IV, V1.0 You pull the trigger, but it turns out that the gun was a poorly designed hand grenade and the whole building blows up.   SQL You cut your foot off, send it out to a service bureau and when it returns, it has a hole in it but will no longer fit the attachment at the end of your leg. or Insert into Foot Select Bullet >From Gun.Hand Where Chamber = 'LOADED' And Trigger = 'PULLED'   Clipper You grab a bullet, get ready to insert it in the gun so that you can shoot yourself in the foot and discover that the gun that the bullets fits has not yet been built, but should be arriving in the mail _REAL_SOON_NOW_. Oracle The menus for coding foot_shooting have not been implemented yet and you can't do foot shooting in SQL.   English You put your foot in your mouth, then bite it off. (For those who don't know, English is a McDonnell Douglas/PICK query language which allegedly requires 110% of system resources to run happily.) Revelation [an implementation of the PICK Operating System] You'll be able to shoot yourself in the foot just as soon as you figure out what all these bullets are for.   FlagShip Starting at the top of your head, you aim the gun at yourself repeatedly until, half an hour later, the gun is finally pointing at your foot and you pull the trigger. A new foot with a hole in it appears but you can't work out how to get rid of the old one and your gun doesn't work anymore.   FidoNet You put your foot in your mouth, then echo it internationally.   PicoSpan [a UNIX-based computer conferencing system] You can't shoot yourself in the foot because you're not a host. or (host variation) Whenever you shoot yourself in the foot, someone opens a topic in policy about it.   Internet You put your foot in your mouth, shoot it, then spam the bullet so that everybody gets shot in the foot.   troff rmtroff -ms -Hdrwp | lpr -Pwp2 & .*place bullet in footer .B .NR FT +3i .in 4 .bu Shoot! .br .sp .in -4 .br .bp NR HD -2i .*   Genetic Algorithms You create 10,000 strings describing the best way to shoot yourself in the foot. By the time the program produces the optimal solution, humans have evolved wings and the problem is moot.   CSP (Communicating Sequential Processes) You only fail to shoot everything that isn't your foot.   MS-SQL Server MS-SQL Server’s gun comes pre-loaded with an unlimited supply of Teflon coated bullets, and it only has two discernible features: the muzzle and the trigger. If that wasn't enough, MS-SQL Server also puts the gun in your hand, applies local anesthetic to the skin of your forefinger and stitches it to the gun's trigger. Meanwhile, another process has set up a spinal block to numb your lower body. It will then proceeded to surgically remove your foot, cryogenically freeze it for preservation, and attach it to the muzzle of the gun so that no matter where you aim, you will shoot your foot. In order to avoid shooting yourself in the foot, you need to unstitch your trigger finger, remove your foot from the muzzle of the gun, and have it surgically reattached. Then you probably want to get some crutches and go out to buy a book on SQL Server Performance Tuning.   Sybase Sybase's gun requires assembly, and you need to go out and purchase your own clip and bullets to load the gun. Assembly is complicated by the fact that Sybase has hidden the gun behind a big stack of reference manuals, but it hasn't told you where that stack is. While you were off finding the gun, assembling it, buying bullets, etc., Sybase was also busy surgically removing your foot and cryogenically freezing it for preservation. Instead of attaching it to the muzzle of the gun, though, it packed your foot on dry ice and sent it UPS-Ground to an unnamed hookah bar somewhere in the middle east. In order to shoot your foot, you must modify your gun with a GPS system for targeting and hire some guy named "Indy" to find the hookah bar and wire the coordinates back to you. By this time, you've probably become so daunted at the tasks stand between you and shooting your foot that you hire a guy who's read all the books on Sybase to help you shoot your foot. If you're lucky, he'll be smart enough both to find your foot and to stop you from shooting it.   Magic software You spend 1 week looking up the correct syntax for GUN. When you find it, you realise that GUN will not let you shoot in your own foot. It will allow you to shoot almost anything but your foot. You then decide to build your own gun. You can't use the standard barrel since this will only allow for standard bullets, which will not fire if the barrel is pointed at your foot. After four weeks, you have created your own custom gun. It blows up in your hand without warning, because you failed to initialise the safety catch and it doesn't know whether the initial state is "0", 0, NULL, "ZERO", 0.0, 0,0, "0.0", or "0,00". You fix the problem with your remaining hand by nesting 12 safety catches, and then decide to build the gun without safety catch. You then shoot the management and retire to a happy life where you code in languages that will allow you to shoot your foot in under 10 days.FirefoxLets you shoot yourself in as many feet as you'd like, while using multiple great addons! IEA moving target in terms of standard ammunition size and doesn't always work properly with non-Microsoft ammunition, so sometimes you shoot something other than your foot. However, it's the corporate world's standard foot-shooting apparatus. Hackers seem to enjoy rigging websites up to trigger cascading foot-shooting failures. Windows 98 About the same as Windows 95 in terms of overall bullet capacity and triggering mechanisms. Includes updated DirectShot API. A new version was released later on to support USB guns, Windows 98 SE.WPF:You get your baseball glove and a ball and you head out to your backyard, where you throw balls to your pitchback. Then your unkempt-haired-cargo-shorts-and-sandals-with-white-socks-wearing neighbor uses XAML to sculpt your arm into a gun, the ball into a bullet and the pitchback into your foot. By now, however, only the neighbor can get it to work and he's only around from 6:30 PM - 3:30 AM. LOGO: You very carefully lay out the trajectory of the bullet. Then you start the gun, which fires very slowly. You walk precisely to the point where the bullet will travel and wait, but just before it gets to you, your class time is up and one of the other kids has already used the system to hack into Sony's PS3 network. Flash: Someone has designed a beautiful-looking gun that anyone can shoot their feet with for free. It weighs six hundred pounds. All kinds of people are shooting themselves in the feet, and sending the link to everyone else so that they can too. That is, except for the criminals, who are all stealing iOS devices that the gun won't work with.APL: Its (mostly) all greek to me. Lisp: Place ((gun in ((hand sight (foot then shoot))))) (Lots of Insipid Stupid Parentheses)Apple OS/X and iOS Once a year, Steve Jobs returns from sick leave to tell millions of unwavering fans how they will be able to shoot themselves in the foot differently this year. They retweet and blog about it ad nauseam, and wait in line to be the first to experience "shoot different".Windows ME Usually fails, even at shooting you in the foot. Yo dawg, I heard you like shooting yourself in the foot. So I put a gun in your gun, so you can shoot yourself in the foot while you shoot yourself in the foot. (Okay, I'm not especially proud of this joke.) Windows 2000 Now you really do have to log in, before you are allowed to shoot yourself in the foot.Windows XPYou thought you learned your lesson: Don't use Windows ME. Then, along came this new creature, built on top of Windows NT! So you spend the next couple days installing antivirus software, patches and service packs, just so you can get that driver to install, and then proceed to shoot yourself in the foot. Windows Vista Newer! Glossier! Shootier! Windows 7 The bullets come out a lot smoother. Active Directory Each bullet now has an attached Bullet Identifier, and can be uniquely identified. Policies can be applied to dictate fragmentation, and the gun will occasionally have a confusing delay after the trigger has been pulled. PythonYou try to use import foot; foot.shoot() only to realize that's only available in 3.0, to which you can't yet upgrade from 2.7 because of all those extension libs lacking support. Solaris Shoots best when used on SPARC hardware, but still runs the trigger GUI under Java. After weeks of learning the appropriate STOP command to prevent the trigger from automatically being pressed on boot, you think you've got it under control. Then the one time you ever use dtrace, it hits a bug that fires the gun. MySQL The feature that allows you to shoot yourself in the foot has been in development for about 6 years, and they are adding it into the next version, which is coming out REAL SOON NOW, promise! But you can always check it out of source control and try it yourself (just not in any environment where data integrity is important because it will probably explode.) PostgreSQLAllows you to have a smug look on your face while you shoot yourself in the foot, because those MySQL guys STILL don't have that feature. NoSQL Barrel? Who needs a barrel? Just put the bullet on your foot, and strike it with a hammer. See? It's so much simpler and more efficient that way. You can even strike multiple bullets in one swing if you swing with a good enough arc, because hammers are easy to use. Getting them to synchronize is a little difficult, though.Eclipse There are about a dozen different packages for shooting yourself in the foot, with weird interdependencies on outdated components. Once you finally navigate the morass and get one installed, you then have something to look at while you shoot yourself in the foot with that package: You can watch the screen redraw.Outlook Makes it really easy to let everyone know you shot yourself in the foot!Shooting yourself in the foot using delegates.You really need to shoot yourself in the foot but you hate firearms (you don't want any dependency on the specifics of shooting) so you delegate it to somebody else. You don't care how it is done as long is shooting your foot. You can do it asynchronously in case you know you may faint so you are called back/slapped in the face by your shooter/friend (or background worker) when everything is done.C#You prepare the gun and the bullet, carefully modeling all of the physics of a bullet traveling through a foot. Just before you're about to pull the trigger, you stumble on System.Windows.BodyParts.Foot.ShootAt(System.Windows.Firearms.IGun gun) in the extended framework, realize you just wasted the entire afternoon, and shoot yourself in the head.PHP<?phprequire("foot_safety_check.php");?><!DOCTYPE HTML><html><head> <!--Lower!--><title>Shooting me in the foot</title></head> <body> <!--LOWER!!!--><leg> <!--OK, I made this one up...--><footer><?php echo (dungSift($_SERVER['HTTP_USER_AGENT'], "ie"))?("Your foot is safe, but you might want to wear a hard hat!"):("<div class=\"shot\">BANG!</div>"); ?></footer></leg> </body> </html>

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  • Which statically typed languages support intersection types for function return values?

    - by stakx
    Initial note: This question got closed after several edits because I lacked the proper terminology to state accurately what I was looking for. Sam Tobin-Hochstadt then posted a comment which made me recognise exactly what that was: programming languages that support intersection types for function return values. Now that the question has been re-opened, I've decided to improve it by rewriting it in a (hopefully) more precise manner. Therefore, some answers and comments below might no longer make sense because they refer to previous edits. (Please see the question's edit history in such cases.) Are there any popular statically & strongly typed programming languages (such as Haskell, generic Java, C#, F#, etc.) that support intersection types for function return values? If so, which, and how? (If I'm honest, I would really love to see someone demonstrate a way how to express intersection types in a mainstream language such as C# or Java.) I'll give a quick example of what intersection types might look like, using some pseudocode similar to C#: interface IX { … } interface IY { … } interface IB { … } class A : IX, IY { … } class B : IX, IY, IB { … } T fn() where T : IX, IY { return … ? new A() : new B(); } That is, the function fn returns an instance of some type T, of which the caller knows only that it implements interfaces IX and IY. (That is, unlike with generics, the caller doesn't get to choose the concrete type of T — the function does. From this I would suppose that T is in fact not a universal type, but an existential type.) P.S.: I'm aware that one could simply define a interface IXY : IX, IY and change the return type of fn to IXY. However, that is not really the same thing, because often you cannot bolt on an additional interface IXY to a previously defined type A which only implements IX and IY separately. Footnote: Some resources about intersection types: Wikipedia article for "Type system" has a subsection about intersection types. Report by Benjamin C. Pierce (1991), "Programming With Intersection Types, Union Types, and Polymorphism" David P. Cunningham (2005), "Intersection types in practice", which contains a case study about the Forsythe language, which is mentioned in the Wikipedia article. A Stack Overflow question, "Union types and intersection types" which got several good answers, among them this one which gives a pseudocode example of intersection types similar to mine above.

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  • Sorting and Filtering By Model-Based LOV Display Value

    - by Steven Davelaar
    If you use a model-based LOV and you use display type "choice", then ADF nicely displays the display value, even if the table is read-only. In the screen shot below, you see the RegionName attribute displayed instead of the RegionId. This is accomplished by the model-based LOV, I did not modify the Countries view object to include a join with Regions.  Also note the sort icon, the table is sorted by RegionId. This sorting typically results in a bug reported by your test team. Europe really shouldn't come before America when sorting ascending, right? To fix this, we could of course change the Countries view object query and add a join with the Regions table to include the RegionName attribute. If the table is updateable, we still need the choice list, so we need to move the model-based LOV from the RegionId attribute to the RegionName attribute and hide the RegionId attribute in the table. But that is a lot of work for such a simple requirement, in particular if we have lots of model-based choice lists in our view object. Fortunately, there is an easier way to do this, with some generic code in your view object base class that fixes this at once for all model-based choice lists that we have defined in our application. The trick is to override the method getSortCriteria() in the base view object class. By default, this method returns null because the sorting is done in the database through a SQL Order By clause. However, if the getSortCriteria method does return a sort criteria the framework will perform in memory sorting which is what we need to achieve sorting by region name. So, inside this method we need to evaluate the Order By clause, and if the order by column matches an attribute that has a model-based LOV choicelist defined with a display attribute that is different from the value attribute, we need to return a sort criterria. Here is the complete code of this method: public SortCriteria[] getSortCriteria() {   String orderBy = getOrderByClause();          if (orderBy!=null )   {     boolean descending = false;     if (orderBy.endsWith(" DESC"))      {       descending = true;       orderBy = orderBy.substring(0,orderBy.length()-5);     }     // extract column name, is part after the dot     int dotpos = orderBy.lastIndexOf(".");     String columnName = orderBy.substring(dotpos+1);     // loop over attributes and find matching attribute     AttributeDef orderByAttrDef = null;     for (AttributeDef attrDef : getAttributeDefs())     {       if (columnName.equals(attrDef.getColumnName()))       {         orderByAttrDef = attrDef;         break;       }     }     if (orderByAttrDef!=null && "choice".equals(orderByAttrDef.getProperty("CONTROLTYPE"))          && orderByAttrDef.getListBindingDef()!=null)     {       String orderbyAttr = orderByAttrDef.getName();       String[] displayAttrs = orderByAttrDef.getListBindingDef().getListDisplayAttrNames();       String[] listAttrs = orderByAttrDef.getListBindingDef().getListAttrNames();       // if first list display attributes is not the same as first list attribute, than the value       // displayed is different from the value copied back to the order by attribute, in which case we need to       // use our custom comparator       if (displayAttrs!=null && listAttrs!=null && displayAttrs.length>0 && !displayAttrs[0].equals(listAttrs[0]))       {                  SortCriteriaImpl sc1 = new SortCriteriaImpl(orderbyAttr, descending);         SortCriteria[] sc = new SortCriteriaImpl[]{sc1};         return sc;                           }     }     }   return super.getSortCriteria(); } If this method returns a sort criteria, then the framework will call the sort method on the view object. The sort method uses a Comparator object to determine the sequence in which the rows should be returned. This comparator is retrieved by calling the getRowComparator method on the view object. So, to ensure sorting by our display value, we need to override this method to return our custom comparator: public Comparator getRowComparator() {   return new LovDisplayAttributeRowComparator(getSortCriteria()); } The custom comparator class extends the default RowComparator class and overrides the method compareRows and looks up the choice display value to compare the two rows. The complete code of this class is included in the sample application.  With this code in place, clicking on the Region sort icon nicely sorts the countries by RegionName, as you can see below. When using the Query-By-Example table filter at the top of the table, you typically want to use the same choice list to filter the rows. One way to do that is documented in ADF code corner sample 16 - How To Customize the ADF Faces Table Filter.The solution in this sample is perfectly fine to use. This sample requires you to define a separate iterator binding and associated tree binding to populate the choice list in the table filter area using the af:iterator tag. You might be able to reuse the same LOV view object instance in this iterator binding that is used as view accessor for the model-bassed LOV. However, I have seen quite a few customers who have a generic LOV view object (mapped to one "refcodes" table) with the bind variable values set in the LOV view accessor. In such a scenario, some duplicate work is needed to get a dedicated view object instance with the correct bind variables that can be used in the iterator binding. Looking for ways to maximize reuse, wouldn't it be nice if we could just reuse our model-based LOV to populate this filter choice list? Well we can. Here are the basic steps: 1. Create an attribute list binding in the page definition that we can use to retrieve the list of SelectItems needed to populate the choice list <list StaticList="false" Uses="LOV_RegionId"               IterBinding="CountriesView1Iterator" id="RegionId"/>  We need this "current row" list binding because the implicit list binding used by the item in the table is not accessible outside a table row, we cannot use the expression #{row.bindings.RegionId} in the table filter facet. 2. Create a Map-style managed bean with the get method retrieving the list binding as key, and returning the list of SelectItems. To return this list, we take the list of selectItems contained by the list binding and replace the index number that is normally used as key value with the actual attribute value that is set by the choice list. Here is the code of the get method:  public Object get(Object key) {   if (key instanceof FacesCtrlListBinding)   {     // we need to cast to internal class FacesCtrlListBinding rather than JUCtrlListBinding to     // be able to call getItems method. To prevent this import, we could evaluate an EL expression     // to get the list of items     FacesCtrlListBinding lb = (FacesCtrlListBinding) key;     if (cachedFilterLists.containsKey(lb.getName()))     {       return cachedFilterLists.get(lb.getName());     }     List<SelectItem> items = (List<SelectItem>)lb.getItems();     if (items==null || items.size()==0)     {       return items;     }     List<SelectItem> newItems = new ArrayList<SelectItem>();     JUCtrlValueDef def = ((JUCtrlValueDef)lb.getDef());     String valueAttr = def.getFirstAttrName();     // the items list has an index number as value, we need to replace this with the actual     // value of the attribute that is copied back by the choice list     for (int i = 0; i < items.size(); i++)     {       SelectItem si = (SelectItem) items.get(i);       Object value = lb.getValueFromList(i);       if (value instanceof Row)       {         Row row = (Row) value;         si.setValue(row.getAttribute(valueAttr));                 }       else       {         // this is the "empty" row, set value to empty string so all rows will be returned         // as user no longer wants to filter on this attribute         si.setValue("");       }       newItems.add(si);     }     cachedFilterLists.put(lb.getName(), newItems);     return newItems;   }   return null; } Note that we added caching to speed up performance, and to handle the situation where table filters or search criteria are set such that no rows are retrieved in the table. When there are no rows, there is no current row and the getItems method on the list binding will return no items.  An alternative approach to create the list of SelectItems would be to retrieve the iterator binding from the list binding and loop over the rows in the iterator binding rowset. Then we wouldn't need the import of the ADF internal oracle.adfinternal.view.faces.model.binding.FacesCtrlListBinding class, but then we need to figure out the display attributes from the list binding definition, and possible separate them with a dash if multiple display attributes are defined in the LOV. Doable but less reuse and more work. 3. Inside the filter facet for the column create an af:selectOneChoice with the value property of the f:selectItems tag referencing the get method of the managed bean:  <f:facet name="filter">   <af:selectOneChoice id="soc0" autoSubmit="true"                       value="#{vs.filterCriteria.RegionId}">     <!-- attention: the RegionId list binding must be created manually in the page definition! -->                       <f:selectItems id="si0"                    value="#{viewScope.TableFilterChoiceList[bindings.RegionId]}"/>   </af:selectOneChoice> </f:facet> Note that the managed bean is defined in viewScope for the caching to take effect. Here is a screen shot of the tabe filter in action: You can download the sample application here. 

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  • Only draw visible objects to the camera in 2D

    - by Deukalion
    I have Map, each map has an array of Ground, each Ground consists of an array of VertexPositionTexture and a texture name reference so it renders a texture at these points (as a shape through triangulation). Now when I render my map I only want to get a list of all objects that are visible in the camera. (So I won't loop through more than I have to) Structs: public struct Map { public Ground[] Ground { get; set; } } public struct Ground { public int[] Indexes { get; set; } public VertexPositionNormalTexture[] Points { get; set; } public Vector3 TopLeft { get; set; } public Vector3 TopRight { get; set; } public Vector3 BottomLeft { get; set; } public Vector3 BottomRight { get; set; } } public struct RenderBoundaries<T> { public BoundingBox Box; public T Items; } when I load a map: foreach (Ground ground in CurrentMap.Ground) { Boundaries.Add(new RenderBoundaries<Ground>() { Box = BoundingBox.CreateFromPoints(new Vector3[] { ground.TopLeft, ground.TopRight, ground.BottomLeft, ground.BottomRight }), Items = ground }); } TopLeft, TopRight, BottomLeft, BottomRight are simply the locations of each corner that the shape make. A rectangle. When I try to loop through only the objects that are visible I do this in my Draw method: public int Draw(GraphicsDevice device, ICamera camera) { BoundingFrustum frustum = new BoundingFrustum(camera.View * camera.Projection); // Visible count int count = 0; EffectTexture.World = camera.World; EffectTexture.View = camera.View; EffectTexture.Projection = camera.Projection; foreach (EffectPass pass in EffectTexture.CurrentTechnique.Passes) { pass.Apply(); foreach (RenderBoundaries<Ground> render in Boundaries.Where(m => frustum.Contains(m.Box) != ContainmentType.Disjoint)) { // Draw ground count++; } } return count; } When I try adding just one ground, then moving the camera so the ground is out of frame it still returns 1 which means it still gets draw even though it's not within the camera's view. Am I doing something or wrong or can it be because of my Camera? Any ideas why it doesn't work?

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  • Process Rules!

    - by Ajay Khanna
    One of the key components of a process is “Business Rule”. Business rule takes many forms inside your process definition and in a way is a manifestation of your company’s business policy. Business rules inside the process are used for policy enforcement, governance, decision management, operations efficiency etc. Following are some basic types of rules that can be a part of your process. 1. Process conditions:  These are defined as the process gateways that determine a path process will take depending on the process parameters. For Example, if discount >10% go to approval path : if discount < 10% auto-approve order. 2. Data rules: These business rules are defined as facts in decision table or knowledge base. The process captures all required parameters and submits those to RETE based rules engine. Rules engine processes the data and returns the result back. For example, rules determining your insurance eligibility. 3. Event rules: Here the system is monitoring the various events and events patterns that are emerging inside the process or external to the process. You can define actions or alerts to be triggered when a certain pattern of events emerges over a specified time period. Such types of rules need Complex Event Processing and are used in applications like Credit Card Fraud detection or Utility Demand Response. 4. User Interface Rules: In order to add dynamic behavior to UI or to keep users from making mistakes and enforcing policy, another mechanism available is UI rules. They are evaluated as the end user is filling out the web forms. These may include enabling and disabling of UI as per business policy. An example could be, if the age of a user is less than 13 years, disable credit card field and enable parental approval required checkbox. Your process may include many of such rule types. Oracle OpenWorld provides a unique opportunity to listen to Oracle Business Process Management Experts and Customers.  We will discuss business rules during various sessions in Oracle OpenWorld. Two of the sessions specifically focused on business rules are listed below: Accelerating an Implementation of Complex Worldwide Business Approval Rules Wednesday, Oct 3, 10:15 AM Moscone South – 305 Oracle Business Rules Use Cases Design and Testing Wednesday, Oct 3, 3:30 PM Marriott Marquis - Golden Gate C3   Oracle Business Process Management Track covers a variety of topics, and speakers covering technology, methodology and best practices. You can see the list of Business process Management sessions here. Come back to this blog for more coverage from Oracle OpenWorld!

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  • Ajaxy

    - by Chris Skardon
    Today is the big day, the day I attempt to use Ajax in the app… I’ve never done this (well, tell a lie, I’ve done it in a ‘tutorial’ site, but that was a while ago now), so it’s going to be interesting.. OK, basics first, let’s start with the @Ajax.ActionLink Right, first stab: @Ajax.ActionLink("Click to get latest", "LatestEntry", new AjaxOptions { UpdateTargetId = "ajaxEntrant", InsertionMode = InsertionMode.Replace, HttpMethod = "GET" }) As far as I’m aware, I’m asking to get the ‘LatestEntry’ from the current controller, and in doing so, I will replace the #ajaxEntrant DOM bit with the result. So. I guess I’d better get the result working… To the controller! public PartialResult LatestEntry() { var entrant =_db.Entrants.OrderByDescending(e => e.Id).Single(); return PartialView("_Entrant", entrant); } Pretty simple, just returns the last entry in a PartialView… but! I have yet to make my partial view, so onto that! @model Webby.Entrant <div class="entrant"> <h4>@Model.Name</h4> </div> Again, super simple, (I’m really just testing at this point)… All the code is now there (as far as I know), so F5 and in… And once again, in the traditionally disappointing way of the norm, it doesn’t work, sure… it opens the right view, but it doesn’t replace the #ajaxEntry DOM element, rather it replaces the whole page… The source code (again, as far as I know) looks ok: <a data-ajax="true" data-ajax-method="GET" data-ajax-mode="replace" data-ajax-update="#ajaxEntrants" href="/Entrants/LatestEntrant">Click to get latest</a> Changing the InsertionMode to any of the other modes has the same effect.. It’s not the DOM name either, changing that has the same effect.. i.e. none. It’s not the partial view either, just making that a <p> has (again) no effect… Ahhhhh --- what a schoolboy error… I had neglected (ahem) to actually put the script bit into the calling page (another save from stackoverflow): <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.js")" type="text/javascript"></script> I’ve now stuck that into the _Layout.cshtml view temporarily to aid the development process… :) Onwards and upwards! Chris

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  • SQL – Contest to Get The Date – Win USD 50 Amazon Gift Cards and Cool Gift

    - by Pinal Dave
    If you are a regular reader of this blog – you will find no issue at all in resolving this puzzle. This contest is based on my experience with NuoDB. If you are not familiar with NuoDB, here are few pointers for you. Step by Step Guide to Download and Install NuoDB – Getting Started with NuoDB Quick Start with Admin Sections of NuoDB – Manage NuoDB Database Quick Start with Explorer Sections of NuoDB – Query NuoDB Database In today’s contest you have to answer following questions: Q 1: Precision of NOW() What is the precision of the NuoDB’s NOW() function, which returns current date time? Hint: Run following script on NuoDB Console Explorer section: SELECT NOW() AS CurrentTime FROM dual; Here is the image. I have masked the area where the time precision is displayed. Q 2: Executing Date and Time Script When I execute following script - SELECT 'today' AS Today, 'tomorrow' AS Tomorrow, 'yesterday' AS Yesterday FROM dual; I will get the following result:   NOW – What will be the answer when we execute following script? and WHY? SELECT CAST('today' AS DATE) AS Today, CAST('tomorrow' AS DATE) AS Tomorrow, CAST('yesterday'AS DATE) AS Yesterday FROM dual; HINT: Install NuoDB (it takes 90 seconds). Prizes: 2 Amazon Gifts 2 Limited Edition Hoodies (US resident only)   Rules: Please leave an answer in the comments section below. You must answer both the questions together in a single comment. US resident who wants to qualify to win NuoDB apparel please mention your country in the comment. You can resubmit your answer multiple times, the latest entry will be considered valid. Last day to participate in the puzzle is June 24, 2013. All valid answer will be kept hidden till June 24, 2013. The winner will be announced on June 25, 2013. Two Winners will get USD 25 worth Amazon Gift Card. (Total Value = 25 x 2 = 50 USD) The winner will be selected using a random algorithm from all the valid answers. Anybody with a valid email address can take part in the contest. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: NuoDB

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