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  • Action delegate in C#

    - by Jalpesh P. Vadgama
    In last few posts about I have written lots of things about delegates and this post is also part of that series. In this post we are going to learn about Action delegates in C#.  Following is a list of post related to delegates. Delegates in C#. Multicast Delegates in C#. Func Delegates in C#. Action Delegates in c#: As per MSDN action delegates used to pass a method as parameter without explicitly declaring custom delegates. Action Delegates are used to encapsulate method that does not have return value. C# 4.0 Action delegates have following different variants like following. It can take up to 16 parameters. Action – It will be no parameter and does not return any value. Action(T) Action(T1,T2) Action(T1,T2,T3) Action(T1,T2,T3,T4) Action(T1,T2,T3,T4,T5) Action(T1,T2,T3,T4,T5,T6) Action(T1,T2,T3,T4,T5,T6,T7) Action(T1,T2,T3,T4,T5,T6,T7,T8) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15,T16) So for this Action delegate you can have up to 16 parameters for Action.  Sound interesting!!… Enough theory now. It’s time to implement real code. Following is a code for that. using System; using System.Collections.Generic; namespace DelegateExample { class Program { static void Main(string[] args) { Action<String> Print = p => Console.WriteLine(p); Action<String,String> PrintAnother = (p1,p2)=> Console.WriteLine(string.Format("{0} {1}",p1,p2)); Print("Hello"); PrintAnother("Hello","World"); } } } In the above code you can see that I have created two Action delegate Print and PrintAnother. Print have one string parameter and its printing that. While PrintAnother have two string parameter and printing both the strings via Console.Writeline. Now it’s time to run example and following is the output as expected. That’s it. Hope you liked it. Stay tuned for more updates!!

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  • Deterministic/Consistent Unique Masking

    - by Dinesh Rajasekharan-Oracle
    One of the key requirements while masking data in large databases or multi database environment is to consistently mask some columns, i.e. for a given input the output should always be the same. At the same time the masked output should not be predictable. Deterministic masking also eliminates the need to spend enormous amount of time spent in identifying data relationships, i.e. parent and child relationships among columns defined in the application tables. In this blog post I will explain different ways of consistently masking the data across databases using Oracle Data Masking and Subsetting The readers of post should have minimal knowledge on Oracle Enterprise Manager 12c, Application Data Modeling, Data Masking concepts. For more information on these concepts, please refer to Oracle Data Masking and Subsetting document Oracle Data Masking and Subsetting 12c provides four methods using which users can consistently yet irreversibly mask their inputs. 1. Substitute 2. SQL Expression 3. Encrypt 4. User Defined Function SUBSTITUTE The substitute masking format replaces the original value with a value from a pre-created database table. As the method uses a hash based algorithm in the back end the mappings are consistent. For example consider DEPARTMENT_ID in EMPLOYEES table is replaced with FAKE_DEPARTMENT_ID from FAKE_TABLE. The substitute masking transformation that all occurrences of DEPARTMENT_ID say ‘101’ will be replaced with ‘502’ provided same substitution table and column is used , i.e. FAKE_TABLE.FAKE_DEPARTMENT_ID. The following screen shot shows the usage of the Substitute masking format with in a masking definition: Note that the uniqueness of the masked value depends on the number of columns being used in the substitution table i.e. if the original table contains 50000 unique values, then for the masked output to be unique and deterministic the substitution column should also contain 50000 unique values without which only consistency is maintained but not uniqueness. SQL EXPRESSION SQL Expression replaces an existing value with the output of a specified SQL Expression. For example while masking an EMPLOYEES table the EMAIL_ID of an employee has to be in the format EMPLOYEE’s [email protected] while FIRST_NAME and LAST_NAME are the actual column names of the EMPLOYEES table then the corresponding SQL Expression will look like %FIRST_NAME%||’.’||%LAST_NAME%||’@COMPANY.COM’. The advantage of this technique is that if you are masking FIRST_NAME and LAST_NAME of the EMPLOYEES table than the corresponding EMAIL ID will be replaced accordingly by the masking scripts. One of the interesting aspect’s of a SQL Expressions is that you can use sub SQL expressions, which means that you can write a nested SQL and use it as SQL Expression to address a complex masking business use cases. SQL Expression can also be used to consistently replace value with hashed value using Oracle’s PL/SQL function ORA_HASH. The following SQL Expression will help in the previous example for replacing the DEPARTMENT_IDs with a hashed number ORA_HASH (%DEPARTMENT_ID%, 1000) The following screen shot shows the usage of encrypt masking format with in the masking definition: ORA_HASH takes three arguments: 1. Expression which can be of any data type except LONG, LOB, User Defined Type [nested table type is allowed]. In the above example I used the Original value as expression. 2. Number of hash buckets which can be number between 0 and 4294967295. The default value is 4294967295. You can also co-relate the number of hash buckets to a range of numbers. In the above example above the bucket value is specified as 1000, so the end result will be a hashed number in between 0 and 1000. 3. Seed, can be any number which decides the consistency, i.e. for a given seed value the output will always be same. The default seed is 0. In the above SQL Expression a seed in not specified, so it to 0. If you have to use a non default seed then the function will look like. ORA_HASH (%DEPARTMENT_ID%, 1000, 1234 The uniqueness depends on the input and the number of hash buckets used. However as ORA_HASH uses a 32 bit algorithm, considering birthday paradox or pigeonhole principle there is a 0.5 probability of collision after 232-1 unique values. ENCRYPT Encrypt masking format uses a blend of 3DES encryption algorithm, hashing, and regular expression to produce a deterministic and unique masked output. The format of the masked output corresponds to the specified regular expression. As this technique uses a key [string] to encrypt the data, the same string can be used to decrypt the data. The key also acts as seed to maintain consistent outputs for a given input. The following screen shot shows the usage of encrypt masking format with in the masking definition: Regular Expressions may look complex for the first time users but you will soon realize that it’s a simple language. There are many resources in internet, oracle documentation, oracle learning library, my oracle support on writing a Regular Expressions, out of all the following My Oracle Support document helped me to get started with Regular Expressions: Oracle SQL Support for Regular Expressions[Video](Doc ID 1369668.1) USER DEFINED FUNCTION [UDF] User Defined Function or UDF provides flexibility for the users to code their own masking logic in PL/SQL, which can be called from masking Defintion. The standard format of an UDF in Oracle Data Masking and Subsetting is: Function udf_func (rowid varchar2, column_name varchar2, original_value varchar2) returns varchar2; Where • rowid is the row identifier of the column that needs to be masked • column_name is the name of the column that needs to be masked • original_value is the column value that needs to be masked You can achieve deterministic masking by using Oracle’s built in hash functions like, ORA_HASH, DBMS_CRYPTO.MD4, DBMS_CRYPTO.MD5, DBMS_UTILITY. GET_HASH_VALUE.Please refers to the Oracle Database Documentation for more information on the Oracle Hash functions. For example the following masking UDF generate deterministic unique hexadecimal values for a given string input: CREATE OR REPLACE FUNCTION RD_DUX (rid varchar2, column_name varchar2, orig_val VARCHAR2) RETURN VARCHAR2 DETERMINISTIC PARALLEL_ENABLE IS stext varchar2 (26); no_of_characters number(2); BEGIN no_of_characters:=6; stext:=substr(RAWTOHEX(DBMS_CRYPTO.HASH(UTL_RAW.CAST_TO_RAW(text),1)),0,no_of_characters); RETURN stext; END; The uniqueness depends on the input and length of the string and number of bits used by hash algorithm. In the above function MD4 hash is used [denoted by argument 1 in the DBMS_CRYPTO.HASH function which is a 128 bit algorithm which produces 2^128-1 unique hashed values , however this is limited by the length of the input string which is 6, so only 6^6 unique values will be generated. Also do not forget about the birthday paradox/pigeonhole principle mentioned earlier in this post. An another example is to consistently replace characters or numbers preserving the length and special characters as shown below: CREATE OR REPLACE FUNCTION RD_DUS(rid varchar2,column_name varchar2,orig_val VARCHAR2) RETURN VARCHAR2 DETERMINISTIC PARALLEL_ENABLE IS stext varchar2(26); BEGIN DBMS_RANDOM.SEED(orig_val); stext:=TRANSLATE(orig_val,'ABCDEFGHILKLMNOPQRSTUVWXYZ',DBMS_RANDOM.STRING('U',26)); stext:=TRANSLATE(stext,'abcdefghijklmnopqrstuvwxyz',DBMS_RANDOM.STRING('L',26)); stext:=TRANSLATE(stext,'0123456789',to_char(DBMS_RANDOM.VALUE(1,9))); stext:=REPLACE(stext,'.','0'); RETURN stext; END; The following screen shot shows the usage of an UDF with in a masking definition: To summarize, Oracle Data Masking and Subsetting helps you to consistently mask data across databases using one or all of the methods described in this post. It saves the hassle of identifying the parent-child relationships defined in the application table. Happy Masking

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  • Why do business analysts and project managers get higher salaries than programmers?

    - by jpartogi
    We have to admit that programming is much more difficult than creating documentation or even creating Gantt chart and asking progress to programmers. So for us that are naives, knowing that programming are generally more difficult, why does business analysts and project managers gets higher salary than programmers? What is it that makes their job a high paying job when even at most time programmers are the ones that goes home late?

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  • Twazzup and App Engine

    Twazzup and App Engine An interview with the developers behind twazzup.com on how App Engine helps them run their application. From: GoogleDevelopers Views: 1298 7 ratings Time: 08:37 More in Science & Technology

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  • ArchBeat Link-o-Rama Top 10 for November 1, 2012

    - by Bob Rhubart
    Hurricane Sandy Edition Power outages in the Cleveland area made it impossible to publish posts on Tuesday and Wednesday. In my neighborhood most are still without power. The sound of howling winds that dominated on Monday and Tuesday has been replaced by the sound of of portable generators. My internet connection was restored only after AT&T U-Verse crewmen hooked up a portable generator to power the relay station up the street. Bear in mind that Cleveland is 500 miles from the Atlantic coast. Mobile Development Platform Strategy Chart: ADF Mobile, WebCenter Sites, Portal, Content and Social "Unlike desktop web focused efforts, the world of mobile has undergone change at a feverish pace," says social enterprise expert John Brunswick. His extensive post charts various resources that will help you keep up. ADF Essentials - The Bare Necessities | Floyd Teter The experiment is over... And now Oracle ACE Director Floyd Teter shares his impressions after spending some time with Oracle ADF Essentials, the free version of Oracle ADF. Expanding the Oracle Enterprise Repository with functional documentation Capgemini middleware specialist Marc Kuijpers shares information on how Oracle Enterprise Repository can be configured "to contain functional assets, i.e. functional designs, use cases and a logical data model" to aid in SOA governance efforts. A review of Oracle SOA Suite 11g Administrator’s Handbook | RedStack "More so than any other single piece of content that I have seen on the topic, it provides the information that a SOA administrator needs to know in order to successfully configure, manage, monitor, troubleshoot and backup an Oracle SOA environment." So says Oracle Fusion Middleware A-Team solution architect Mark Nelson of Oracle SOA Suite 11g Administrator’s Handbook, by Ahmed Aboulnaga and Arun Pareek. Eating our own dog food – Oracle’s internal deployment of Oracle IDM Oracle Fusion Middleware A-Team member Brian Eidelman recommends the recent podcast on Oracle’s internal deployment of Oracle OAM and OID. "This was a big project that involved migrating a bunch of critical, high volume applications to leverage OAM and OID," says Eidelman. "So I suggest you tune in to see and hear more about how we deploy our own software." Thought for the Day "Anyone who says they're not afraid at the time of a hurricane is either a fool or a liar, or a little bit of both." — Anderson Cooper Source: BrainyQuote

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  • 12.04.1 desktop monitor "Out of Range"

    - by Zach
    I know this question has been asked many-a-times, but I cant seem to get a definite answer to it. I am running 12.04.1 on my HP Pavillion a6 109n PC. Processor is a AMD Athlon 64 x2 Dual core Processor. Every time I boot up my desktop, it runs BIOS, then it boots up Linux. After about 10 seconds, a little blue screen comes up saying: Out of Range: H. Frequency: 92.7KHz V. Frequency: 58.3Hz Can anyone help with this?

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  • Google I/O 2010 - Developing web apps for Chrome Web Store

    Google I/O 2010 - Developing web apps for Chrome Web Store Google I/O 2010 - Developing web apps for the Chrome Web Store Chrome 101 Erik Kay Google Chrome is a powerful platform for developing web apps. With Chrome web apps, we're making it easier for users to discover and use these apps. Learn how to build and sell apps for the Chrome Web Store. For all I/O 2010 sessions, please go to code.google.com From: GoogleDevelopers Views: 8 0 ratings Time: 01:00:29 More in Science & Technology

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  • Quick Poll: Certification Information Preferences

    - by Paul Sorensen
    We're starting a new "quick poll" series so that we can better learn about you - our technical professionals who are either already Oracle certified or working on earning an Oracle credential. We aim to keep them short (~1 minute to answer) so that you'll share your opinion.This week we want to know how you prefer to get your information about Oracle Certification:TAKE THE QUICK POLLNOTE: You can only take the survey once per machine. (if you try a second time it may redirect you to an external website)

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  • Windows Phone 8 SDK

    - by Nikita Polyakov
    Yesterday, the new Windows Phone 8 was announced! Find out more about the cool new OS and the new devices supporting it at www.WindowsPhone.com Today at BUILD conference in Redmond, WA – Microsoft has announced general availability of the Developer SDK for Windows Phone 8! Get the SDK and more info in the dev center: http://dev.WindowsPhone.com Also watch the Windows Phone Developer blog. Also this is the best time to join the Windows Phone Store for just for $8 for next 8 days.

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  • Tips on ensuring Model Quality

    - by [email protected]
    Given enough data that represents well the domain and models that reflect exactly the decision being optimized, models usually provide good predictions that ensure lift. Nevertheless, sometimes the modeling situation is less than ideal. In this blog entry we explore the problems found in a few such situations and how to avoid them.1 - The Model does not reflect the problem you are trying to solveFor example, you may be trying to solve the problem: "What product should I recommend to this customer" but your model learns on the problem: "Given that a customer has acquired our products, what is the likelihood for each product". In this case the model you built may be too far of a proxy for the problem you are really trying to solve. What you could do in this case is try to build a model based on the result from recommendations of products to customers. If there is not enough data from actual recommendations, you could use a hybrid approach in which you would use the [bad] proxy model until the recommendation model converges.2 - Data is not predictive enoughIf the inputs are not correlated with the output then the models may be unable to provide good predictions. For example, if the input is the phase of the moon and the weather and the output is what car did the customer buy, there may be no correlations found. In this case you should see a low quality model.The solution in this case is to include more relevant inputs.3 - Not enough cases seenIf the data learned does not include enough cases, at least 200 positive examples for each output, then the quality of recommendations may be low. The obvious solution is to include more data records. If this is not possible, then it may be possible to build a model based on the characteristics of the output choices rather than the choices themselves. For example, instead of using products as output, use the product category, price and brand name, and then combine these models.4 - Output leaking into input giving the false impression of good quality modelsIf the input data in the training includes values that have changed or are available only because the output happened, then you will find some strong correlations between the input and the output, but these strong correlations do not reflect the data that you will have available at decision (prediction) time. For example, if you are building a model to predict whether a web site visitor will succeed in registering, and the input includes the variable DaysSinceRegistration, and you learn when this variable has already been set, you will probably see a big correlation between having a Zero (or one) in this variable and the fact that registration was successful.The solution is to remove these variables from the input or make sure they reflect the value as of the time of decision and not after the result is known. 

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  • Slides, Code, and Photos from SPTechCon San Francisco 2011

    - by Brian Jackett
    Note: Updated 2/12/11 with links to both presentation materials.     This past week I presented two sessions at SPTechCon San Francisco 2011.  The first session was “The Expanding Developer Toolbox for SharePoint 2010” which .  Thanks to all of my attendees for this session.  They had so many great questions that we ran out of time before covering all of the planned material.  Especially for them I’ve provided the slides and code samples to walk through them on their own.     The second session was “Real World Deployment of SharePoint 2007 Solutions”.  In talking with attendees before the session many were looking for 2007 content.  At the conference SharePoint 2010 was represented much more heavily than 2007, so I was glad to fill a need in the community. Slides and Code   Click here for “The Expanding Developer Toolbox for SharePoint 2010” materials   Click here for “Real World Deployment of SharePoint 2007 Solutions” materials Photos Pictures on FaceBook   Click here Pictures on Windows Live (higher res)     SPTechCon San Fran Feb 2011 VIEW SLIDE SHOW DOWNLOAD ALL Side Trips     Aside from the conference itself I also got to take a few side trips during the nights.  A special thanks to Dux Raymond Sy (Twitter) for organizing a Mongolian Hot Pot dinner on Monday (see pictures) and Michael Noel (Twitter) for organizing a Korean bbq dinner on Tuesday (again see pictures).  These were both new experiences for me and I thoroughly enjoyed the time with friends and trying something new.  Another thanks to Mark Miller (Twitter) for giving a personal tour around various sites of San Fran to myself and a few others.  It was great hearing the backstory of different neighborhoods and buildings from someone who had lived in the area for years.  Overall a great addition to the conference itself. Conclusion     This is the 3rd SPTechCon I’ve attended and the conference is getting better with each iteration.  The fine folks at BZ Media should be proud of the effort they’ve put in.  The next SPTechCon will be in Boston in June.  As of right now I won’t be attending that one but I highly recommend anyone to go if you have the chance.         -Frog Out

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  • How to implement a simple bullet trajectory

    - by AirieFenix
    I searched and searched and although it's a fair simple question, I don't find the proper answer but general ideas (which I already have). I have a top-down game and I want to implement a gun which shoots bullets that follow a simple path (no physics nor change of trajectory, just go from A to B thing). a: vector of the position of the gun/player. b: vector of the mouse position (cross-hair). w: the vector of the bullet's trajectory. So, w=b-a. And the position of the bullet = [x=x0+speed*time*normalized w.x , y=y0+speed*time * normalized w.y]. I have the constructor: public Shot(int shipX, int shipY, int mouseX, int mouseY) { //I get mouse with Gdx.input.getX()/getY() ... this.shotTime = TimeUtils.millis(); this.posX = shipX; this.posY = shipY; //I used aVector = aVector.nor() here before but for some reason didn't work float tmp = (float) (Math.pow(mouseX-shipX, 2) + Math.pow(mouseY-shipY, 2)); tmp = (float) Math.sqrt(Math.abs(tmp)); this.vecX = (mouseX-shipX)/tmp; this.vecY = (mouseY-shipY)/tmp; } And here I update the position and draw the shot: public void drawShot(SpriteBatch batch) { this.lifeTime = TimeUtils.millis() - this.shotTime; //position = positionBefore + v*t this.posX = this.posX + this.vecX*this.lifeTime*speed*Gdx.graphics.getDeltaTime(); this.posY = this.posY + this.vecY*this.lifeTime*speed*Gdx.graphics.getDeltaTime(); ... } Now, the behavior of the bullet seems very awkward, not going exactly where my mouse is (it's like the mouse is 30px off) and with a random speed. I know I probably need to open the old algebra book from college but I'd like somebody says if I'm in the right direction (or points me to it); if it's a calculation problem, a code problem or both. Also, is it possible that Gdx.input.getX() gives me non-precise position? Because when I draw the cross-hair it also draws off the cursor position. Sorry for the long post and sorry if it's a very basic question. Thanks!

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  • Precompiling LINQ Queries

    Did you know that by precompiling LINQ queries you might actually be degrading your app’s performance if you’re not careful? Julie Lerman explains how to ensure you’re not re-precompiling queries each time and losing the expected performance benefits across post-backs, short-lived service operations and other code where critical instances are going out of scope.

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  • ISO - the language of this installation package is not supported by your system

    - by Rodney Vinyard
    Problem: When attempting to install the extracted ISO image the following error appears: "the language of this installation package is not supported by your system", and exits.  The install does not start.   Solution: Within ISO buster , choose Fileà<ExtractedFileName>à”Extract Raw, but convert to User data”, then rerun the setup.exe that is extracted.   Might save you some time in the future…

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  • Immortal Kombat [Humorous Video]

    - by Asian Angel
    Sometimes the Grim Reaper’s job is quick and simple, but not this time as he comes to claim the soul of an avid gamer. Can they come to an amicable understanding or has this just evolved into Immortal Kombat? Note: Contains what may be considered to be inappropriate imagery just before video credits start. Immortal Kombat [via Dorkly] How to Use an Xbox 360 Controller On Your Windows PC Download the Official How-To Geek Trivia App for Windows 8 How to Banish Duplicate Photos with VisiPic

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  • Server Migration Checklist II

    - by merrillaldrich
    Easy Breezy Login Audit for your Ol’ 2000 Server In the last post on this topic I put up the preparatory steps I’ve been using for server migrations. Here I am posting some code that has worked well for us to trace who/what is connecting to our older SQL Server 2000 machines. It’s a simple audit of login events, tracing the login name, host name, database, and last login time for connections to the server, and gave us valuable insight into who was really using the machines and which databases might...(read more)

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  • Can't install any ubuntu on HP Pavillion DV6-6B01AX 15.6 HD/AMD QC A6

    - by Mohamed Bassyouni
    I have tried over 50 times all different ways to install Ubuntu on (HP Pavillion DV6-6B01AX 15.6 HD/AMD QC A6) from v9 to 12.04 but no success. Every time after booting from the DVD or CD and when asked to install along with Windows 7, I click the Next button but then it goes to shut down, says remove media and press any key. I don't want install it over Windows 7, I want to keep Windows 7. Any help?

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  • Beware of const members

    - by nmarun
    I happened to learn a new thing about const today and how one needs to be careful with its usage. Let’s say I have a third-party assembly ‘ConstVsReadonlyLib’ with a class named ConstSideEffect.cs: 1: public class ConstSideEffect 2: { 3: public static readonly int StartValue = 10; 4: public const int EndValue = 20; 5: } In my project, I reference the above assembly as follows: 1: static void Main(string[] args) 2: { 3: for (int i = ConstSideEffect.StartValue; i < ConstSideEffect.EndValue; i++) 4: { 5: Console.WriteLine(i); 6: } 7: Console.ReadLine(); 8: } You’ll see values 10 through 19 as expected. Now, let’s say I receive a new version of the ConstVsReadonlyLib. 1: public class ConstSideEffect 2: { 3: public static readonly int StartValue = 5; 4: public const int EndValue = 30; 5: } If I just drop this new assembly in the bin folder and run the application, without rebuilding my console application, my thinking was that the output would be from 5 to 29. Of course I was wrong… if not you’d not be reading this blog. The actual output is from 5 through 19. The reason is due to the behavior of const and readonly members. To begin with, const is the compile-time constant and readonly is a runtime constant. Next, when you compile the code, a compile-time constant member is replaced with the value of the constant in the code. But, the IL generated when you reference a read-only constant, references the readonly variable, not its value. So, the IL version of the Main method, after compilation actually looks something like: 1: static void Main(string[] args) 2: { 3: for (int i = ConstSideEffect.StartValue; i < 20; i++) 4: { 5: Console.WriteLine(i); 6: } 7: Console.ReadLine(); 8: } I’m no expert with this IL thingi, but when I look at the disassembled code of the exe file (using IL Disassembler), I see the following: I see our readonly member still being referenced by the variable name (ConstVsReadonlyLib.ConstSideEffect::StartValue) in line 0001. Then there’s the Console.WriteLine in line 000b and finally, see the value of 20 in line 0017. This, I’m pretty sure is our const member being replaced by its value which marks the upper bound of the ‘for’ loop. Now you know why the output was from 5 through 19. This definitely is a side-effect of having const members and one needs to be aware of it. While we’re here, I’d like to add a few other points about const and readonly members: const is slightly faster, but is less flexible readonly cannot be declared within a method scope const can be used only on primitive types (numbers and strings) Just wanted to share this before going to bed!

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  • InvokeRequired not reliable?

    - by marocanu2001
    InvalidOperationException: Cross-thread operation not valid: Control 'progressBar' accessed from a thread other than the thread it was created ... Now this is not a nice way to start a day! not even if it's a Monday! So you have seen this and already thought, come on, this is an old one, just ask whether InvokeRequired before calling the method in the control, something like this: if (progressBar.InvokeRequired) {           progressBar.Invoke  ( new MethodInvoker( delegate {  progressBar.Value = 50;    }) ) }else      progressBar.Value = 50;    Unfortunately this was not working the way I would have expected, I got this error, debugged and though in debugging the InvokeRequired had become true , the error was thrown on the branch that did not required Invoke. So there was a scenario where InvokeRequired returned false and still accessing the control was not on the right thread ... Problem was that I kept showing and hiding the little form showing the progressbar. The progressbar was updating on an event  , ProgressChanged and I could not guarantee the little form was loaded by the time the event was thrown. So , spotted the problem, if none of the parents of the control you try to modify is created at the time of the method invoking, the InvokeRequired returns true! That causes your code to execute on the woring thread. Of course, updating UI before the win dow was created is not a legitimate action either, still I would have expected a different error. MSDN: "If the control's handle does not yet exist, InvokeRequired searches up the control's parent chain until it finds a control or form that does have a window handle. If no appropriate handle can be found, the InvokeRequired method returns false. This means that InvokeRequired can return false if Invoke is not required (the call occurs on the same thread), or if the control was created on a different thread but the control's handle has not yet been created." Have  a look at InvokeRequired's implementation: public bool InvokeRequired {     get     {         HandleRef hWnd;         int lpdwProcessId;         if (this.IsHandleCreated)         {             hWnd = new HandleRef(this, this.Handle);         }         else         {             Control wrapper = this.FindMarshallingControl();             if (!wrapper.IsHandleCreated)             {                 return false; // <==========             }             hWnd = new HandleRef(wrapper, wrapper.Handle);         }         int windowThreadProcessId = SafeNativeMethods.GetWindowThreadProcessId(hWnd, out lpdwProcessId);         int currentThreadId = SafeNativeMethods.GetCurrentThreadId();         return (windowThreadProcessId != currentThreadId);     } } Here 's a good article about this and a workaround http://www.ikriv.com/en/prog/info/dotnet/MysteriousHang.html

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  • What is the best way to store anciliary data with a 2D timeseries object in R?

    - by Mike52
    I currently try to move from matlab to R. I have 2D measurements, consisting of irradiance in time and wavelength together with quality flags and uncertainty and error estimates. In Matlab I extended the timeseries object to store both the wavelength array and the auxiliary data. What is the best way in R to store this data? Ideally I would like this data to be stored together such that e.g. window(...) keeps all data synchronized.

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  • Instructions on how to configure a WebLogic Cluster and use it with Oracle Http Server

    - by Laurent Goldsztejn
    On October 17th I delivered a webcast on WebLogic Clustering that included a demo with Apache as the proxy server.  I realized that many steps are needed to set up the configuration I used during the demo.  The purpose of this article is to go through these steps to show how quickly and easily one can define a new cluster and then proxy requests via an Oracle Http Server (OHS). The domain configuration wizard offers the option to create a cluster.  The administration console or WLST, the Weblogic scripting tool can also be used to define a new cluster.  It can be created at any time but the servers that will participate in it cannot be in a running state. Cluster Creation using the configuration wizard Network and architecture requirements need to be considered while choosing between unicast and multicast. Multicast Vs. Unicast with WebLogic Clustering is of great help to make the best decision between the two messaging modes.  In addition, Configure Cluster offers details on each single field displayed above. After this initial configuration page, individual servers could be assigned to this newly created cluster although servers can be added later to the cluster.  What is not recommended is for the Admin server to participate in a cluster as the main purpose of the Admin server is to perform the bulk of the processing for the domain.  Servers need to stop before being assigned to a cluster.  There is also no minimum number of servers that have to participate in the cluster. At this point the configuration should be done and the cluster created successfully.  This can easily be verified from the console. Each clustered managed server can be launched to join the cluster.   At startup the following messages should be logged for each clustered managed server: <Notice> <WeblogicServer> <BEA-000365> <Server state changed to STARTING> <Notice> <Cluster> <BEA-000197> <Listening for announcements from cluster using messaging_mode cluster messaging> <Notice> <Cluster> <BEA-000133> <Waiting to synchronize with other running members of cluster_name>  It's time to try sending requests to the cluster and we will do this with the help of Oracle Http Server to play the role of a proxy server to demonstrate load balancing.  Proxy Server configuration  The first step is to download Weblogic Server Web Server Plugin that will enhance the web server by handling requests aimed at being sent to the Weblogic cluster.  For our test Oracle Http Server (OHS) will be used.  However plug-ins are also available for Apache Http server, Microsoft Internet Information Server (IIS), Oracle iPlanet Webserver or even WebLogic Server with the HttpClusterServlet. Once OHS is installed on the system, the configuration file, mod_wl_ohs.conf, will need to be altered to include Weblogic proxy specifics. First of all, add the following directive to instruct Apache to load the Weblogic shared object module extracted from the plugins file just downloaded. LoadModule weblogic_module modules/mod_wl_ohs.so and then create an IfModule directive to encapsulate the following location block so that proxy will be enabled by path (each request including /wls will be directed directly to the WebLogic Cluster).  You could also proxy requests by MIME type using MatchExpression in the Location block. <IfModule weblogic_module> <Location /wls>    SetHandler weblogic-handler    PathTrim /wls    WebLogicCluster MS1_URL:port,MS2_URL:port    Debug ON    WLLogFile        c:/tmp/global_proxy.log     WLTempDir        "c:/myTemp"    DebugConfigInfo  On </Location> </IfModule> SetHandler specifies the handler for the plug-in module  PathTrim will instruct the plug-in to trim /w ls from the URL before forwarding the request to the cluster. The list of WebLogic Servers defined in WeblogicCluster could contain a mixed set of clustered and single servers.  However, the dynamic list returned for this parameter will only contain valid clustered servers and may contain more servers if not all clustered servers are listed in WeblogicCluster. Testing proxy and load balancing It's time to start OHS web server which should at this point be configured correctly to proxy requests to the clustered servers.  By default round-robin is the load balancing strategy set by WebLogic. Testing the load balancing can be easily done by disabling cookies on your browser given that a request containing a cookie attempts to connect to the primary server. If that attempt fails, the plug-in attempts to make a connection to the next available server in the list in a round-robin fashion.  With cookies enabled, you could use two different browsers to test the load balancing with a JSP page that contains the following: <%@ page contentType="text/html; charset=iso-8859-1" language="java"  %>  <%  String path = request.getContextPath();   String getProtocol=request.getScheme();   String getDomain=request.getServerName();   String getPort=Integer.toString(request.getLocalPort());   String getPath = getProtocol+"://"+getDomain+":"+getPort+path+"/"; %> <html> <body> Receiving Server <%=getPath%> </body> </html>  Assuming that you name the JSP page Test.jsp and the webapp that contains it TestApp, your browsers should open the following URL: http://localhost/wls/TestApp/Test.jsp  Each browser should connect to a different clustered server and this simple JSP should confirm that.  The webapp that contains the JSP needs to be deployed to the cluster. You can also verify that the load is correctly balanced by looking at the proxy log file.  Each request generates a set of log entries that starts with : timestamp ================New Request: Each request is associated with a primary server and a secondary server if one is available.  For our test request, the following entries should appear in the log as well:Using Uri /wls/TestApp/Test.jsp After trimming path: '/TestApp/Test.jsp' The final request string is '/TestApp/Test.jsp' If an exception occurs, it should also be logged in the proxy log file with the prefix:timestamp *******Exception type   WeblogicBridgeConfig DebugConfigInfo enables runtime statistics and the production of configuration information.  For security purposes, this parameter should be turned off in production. http://webserver_host:port/path/xyz.jsp?__WebLogicBridgeConfig will display a proxy bridge page detailing the plugin configuration followed by runtime statistics which could help in diagnosing issues along with the analyzing of the proxy log file.  In our example the url would be: http://localhost/wls/TestApp/Test.jsp?__WebLogicBridgeConfig  Here is how the top section of the screen can look like: The bottom part of the page contains runtime statistics, here is a snippet of it (unrelated with the previous JSP example).   This entire plugin configuration should be very similar with other web servers, what varies is the name of the proxy server configuration file. So, as you can see, it only takes a few minutes to configure a Weblogic cluster and get servers to join it. 

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  • LEGO – A Hobbit Halloween [Video]

    - by Asian Angel
    Pippin and Merry are up to their old pranks once again, but this time they quickly get in over their heads while looking to indulge in a bit of Halloween fun! LEGO A Hobbit Halloween [via Neatorama] What Is the Purpose of the “Do Not Cover This Hole” Hole on Hard Drives? How To Log Into The Desktop, Add a Start Menu, and Disable Hot Corners in Windows 8 HTG Explains: Why You Shouldn’t Use a Task Killer On Android

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  • Databinder.Eval using Lamda Expressions

    Using lambda expression to help with compile time checking of Eval statements...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Geek City: Clearing Plans for a Single Database

    - by Kalen Delaney
    I know Friday afternoon isn't the best time for blogging, as everyone is going home now, and by Monday morning, this post will be old news. But I'm not shutting down just yet, and a something came up this week that I just realized not everybody knew about, so I decided to blog it. Many (or most?) of you are aware that you can clear all cached plans using DBCC FREEPROCCACHE. In addition, there are certain configuration options, for which changing their values will cause all plans in cache to be removed....(read more)

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