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  • JDBC resultset close

    - by KM
    I am doing profiling of my Java application and found some interesting statistics for a jdbc PreparedStatement call: Given below is the environment details: Database: Sybase SQL Anywhere 10.0.1 Driver: com.sybase.jdbc3.jdbc.SybDriver connection pool: c3p0 JRE: 1.6.0_05 The code in question is given below: try { ps = conn.prepareStatement(sql); ps.setDouble(...); rs = ps.executeQuery(); ...... return xyz; } finally { try { if (rs != null) rs.close(); if (ps != null) ps.close(); } catch (SQLException sqlEx) { } } From JProfiler stats, I find that this particular resultspace.close() statement alone takes a large amount of time. It varies from 25 ms to 320s while for other code blocks which are of identical in nature, i find that this takes close to 20 microseconds. Just to be sure, I ran this performance test multiple times and confirmed this data. I am puzzled by this behaviour - Thoughts?

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  • Objective C message dispatch mechanism

    - by Dolphin
    I am just staring to play around with Objective C (writing toy iPhone apps) and I am curious about the underlying mechanism used to dispatch messages. I have a good understanding of how virtual functions in C++ are generally implemented and what the costs are relative to a static or non-virtual method call, but I don't have any background with Obj-C to know how messages are sent. Browsing around I found this loose benchmark and it mentions IMP cached messages being faster than virtual function calls, which are in turn faster than a standard message send. I am not trying to optimize anything, just get deeper understanding of how exactly the messages get dispatched. How are Obj-C messages dispatched? How do Instance Method Pointers get cached and can you (in general) tell by reading the code if a message will get cached? Are class methods essentially the same as a C function (or static class method in C++), or is there something more to them? I know some of these questions may be 'implementation dependent' but there is only one implementation that really counts.

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  • Sleep function in ORACLE

    - by Salvador
    I need execute an sql query in ORACLE it takes a certain amount of time. so i wrote this function CREATE OR REPLACE FUNCTION MYSCHEMA.TEST_SLEEP ( TIME_ IN NUMBER ) RETURN INTEGER IS BEGIN DBMS_LOCK.sleep(seconds => TIME_); RETURN 1; EXCEPTION WHEN OTHERS THEN RAISE; RETURN 1; END TEST_SLEEP; and i call in this way SELECT TEST_SLEEP(10.5) FROM DUAL but to work i need set grant of DBMS_LOCK to the owner of the procedure. how i can rewrite this function without using the DBMS_LOCK.sleep function? Thanks in advance.

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  • linq2sql - where to enlist transaction (repository or bll)?

    - by Caroline Showden
    My app uses a business layer which calls a repository which uses linq to sql. I have an Item class that has an enum type property and an ItemDetail property. I need to implement a delete method that: (1) always delete the Item (2) if the item.type is XYZ and the ItemDetail is not null, delete the ItemDetail as well. My question is where should this logic be housed? If I have it in my business logic which I would prefer, this involves two separate repository calls, each of which uses a separate datacontext. I would have to wrap both calls is a System.Transaction which (in sql 2005) get promoted to a distributed transaction which is not ideal. I can move it all to a single repository call and the transaction will be handled implicitly by the datacontext but feel that this is really business logic so does not belong in the repository. Thoughts? Carrie

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  • Use a "x-dom-event-stream" stream in javascript ?

    - by rnaud
    Hello, HTML5 draft contains an API called EventSource to stream data (notifications) trough javascript using only one server call. Looking it up, I found an exemple on Opera Labs of the javascript part : document.getElementsByTagName("event-source")[0] .addEventListener("server-time", eventHandler, false); function eventHandler(event) { // Alert time sent by the server alert(event.data); } and the server side part : <?php header("Content-Type: application/x-dom-event-stream"); while(true) { echo "Event: server-time\n"; $time = time(); echo "data: $time\n"; echo "\n"; flush(); sleep(3); } ?> But as of today, it seems only Opera has implemented the API, neither Chrome nor Safari have a working version (Am I wrong here ?) So my question is, is there any other way in javascript, maybe more complex, to use this one stream to get data ?

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  • Data in custom attribute not returned in UserProfile object in MOSS

    - by Jason Hocker
    I've created two new custom attributes in the UserProfile. When the service we wrote returns data about a specific user by using the UserProfile object, sometimes the data isn't returned, even though if we look at the user in SSP it look populated. Some users work; this is the first user we set up with data. I'm not sure if sometime in the meantime after setting up the first user and testing, if there's something we ran and need to run again. How can I get all the users to get their data returned in a call to their UserProfile?

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  • How to Maintain per-Client State in a WCF Service?

    - by tbischel
    I've created a WCF service in which I would like it to maintain state between calls from the client. I figured the easiest way to do this was to add this attribute to the service: [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession)] since this is supposed to keep a separate service alive for each client over the life of the client proxy (or timeout in the extreme case). I also added a test function that tracks a list of user inputs, and spits out a concatenated string with all the inputs over the life of the service. When I run this in the test client generated by visual studio, I find that the list I was using to hold past data is reset with each call. Is there something else I need to do to maintain state per session?

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  • Binding elements when modal window loads from AJAX (jQuery)

    - by thinkswan
    I'd like to set up a drag'n'drop list inside a modal window. The window's content is loaded via an AJAX call, so I believe I need to use jQuery's .live() method. Here is my current code: $('#cboxLoadedContent').live('load', function() { // Event for sortable page lists $('ul#pageList').sortable(); }); How can I set up bindings when the modal window loads? The modal window comes from the colorbox plugin. Note: I'm guessing that 'load' is not the right event to use, because if I throw a simple alert() in there, it doesn't even show up when the window loads.

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  • jsonp is not firing beforeSend?

    - by user283357
    Hi All, I am working on a project to call a webservice from different domain using $.ajax with dataType set to jsonp. $.ajax({ type: "GET", url: testService.asmx, async: true, contentType: "application/json; charset=utf-8", dataType: "jsonp", beforeSend: function (XMLHttpRequest) { alert('Before Send'); //Nothing happnes }, success: function (response) { alert('Success'); //this was fired }, complete: function (XMLHttpRequest, textStatus) { alert('After Send'); //this was fired } }); The problem is I have a ...loading animation which I want to display while the web service request is being processed. I tried using "beforeSend:" to show the loading animation but it seems like "beforeSend" is not getting fired. The animation works fine when the app is on the same domain (using jsonp) but when I move the app into a different server, everything works except "beforeSend" is not getting called. So users will not be able to see the loading animation. Is there any workaround for this?

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  • Why the CCLayer can't use a for loop in draw method??

    - by Tattat
    I have a CClayer, that have a draw method, every second, it will call the draw method 60 times. So, I have method like this: -(void)draw{ glEnable(GL_LINE_SMOOTH); glColor4f(0.0f, 1.0f, 0.0f, 1.0f); glLineWidth(5.0f); ccDrawLine(ccp(300,20), CGPointZero); } I work great. but after I added a for looop, for example....: -(void)draw{ glEnable(GL_LINE_SMOOTH); glColor4f(0.0f, 1.0f, 0.0f, 1.0f); glLineWidth(5.0f); ccDrawLine(ccp(300,20), CGPointZero); for(int i=0; i<5; i++){ NSLog(@"Testing the loop, %i", i); } } It can't draw anything, the screen only black. But I can see the Testing the loop is keep calling.... Why? thank you.

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  • Intercept a request to read a particular file and instead generate the apparent output of that file

    - by Mike Atkinson
    Sorry for the long and yet still somehow vague title! A friend of mine has a Flash Action script running on a LAMP server that currently reads an xml config file. He's asked me if it's possible to remove the xml file, and replace it somehow with a system (lets call it an 'auto xml generator') that intercepts the request to read that file and generates an output, so it appears to all intents and purposes as if the file still exists and contains the contents that has actually been returned from our auto xml generator Hours of Googling has failed to come up with any promising leads, can anyone offer any advice? Thanks very much! Mike

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  • How do I debug a DLL from VS2008?

    - by GregH
    I have a program written in VB.Net (Visual Studio 2008) that uses a DLL written in Visual C++ by another developer. I'd like to be able to step in to the C++ code as my code makes calls to methods in the DLL. Since the DLL is it's own solution, I don't think it can be included in my solution/project. I tried putting the DLLs pdb file in the debug/bin directory with the rest of my build and pdb files. However, when I get to the point in stepping through my code, and it gets to the dll call, it just steps right over the dll code. Do I have to manually load symbols? Not sure what I'm doing wrong. Thanks.

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  • Lessons from rewriting POP Forums for MVC, open source-like

    - by Jeff
    It has been a ton of work, interrupted over the last two years by unemployment, moving, a baby, failing to sell houses and other life events, but it's really exciting to see POP Forums v9 coming together. I'm not even sure when I decided to really commit to it as an open source project, but working on the same team as the CodePlex folks probably had something to do with it. Moving along the roadmap I set for myself, the app is now running on a quasi-production site... we launched MouseZoom last weekend. (That's a post-beta 1 build of the forum. There's also some nifty Silverlight DeepZoom goodness on that site.)I have to make a point to illustrate just how important starting over was for me. I started this forum thing for my sites in old ASP more than ten years ago. What a mess that stuff was, including SQL injection vulnerabilities and all kinds of crap. It went to ASP.NET in 2002, but even then, it felt a little too much like script. More than a year later, in 2003, I did an honest to goodness rewrite. If you've been in this business of writing code for any amount of time, you know how much you hate what you wrote a month ago, so just imagine that with seven years in between. The subsequent versions still carried a fair amount of crap, and that's why I had to start over, to make a clean break. Mind you, much of that crap is still running on some of my production sites in a stable manner, but it's a pain in the ass to maintain.So with that clean break, there is much that I have learned. These are a few of those lessons, in no particular order...Avoid shiny object syndromeOver the years, I've embraced new things without bothering to ask myself why. I remember spending the better part of a year trying to adapt this app to use the membership and profile API's in ASP.NET, just because they were there. They didn't solve any known problem. Early on in this version, I dabbled in exotic ORM's, even though I already had the fundamental SQL that I knew worked. I bloated up the client side code with all kinds of jQuery UI and plugins just because, and it got in the way. All the new shiny can be distracting, and I've come to realize that I've allowed it to be a distraction most of my professional life.Just query what you needI've spent a lot of time over-thinking how to query data. In the SQL world, this means exotic joins, special caches, the read-update-commit loop of ORM's, etc. There are times when you have to remind yourself that you aren't Facebook, you'll never be Facebook, and that databases are in fact intended to serve data. In a lot of projects, back in the day, I used to have these big, rich data objects and pass them all over the place, through various application tiers, when in reality, all I needed was some ID from the entity. I try to be mindful of how many queries hit the database on a given request, but I don't obsess over it. I just get what I need.Don't spend too much time worrying about your unit testsIf you've looked at any of the tests for POP Forums, you might offer an audible WTF. That's OK. There's a whole lot of mocking going on. In some cases, it points out where you're doing too much, and that's good for improving your design. In other cases it shows where your design sucks. But the biggest trap of unit testing is that you worry it should be prettier. That's a waste of time. When you write a test, in many cases before the production code, the important part is that you're testing the right thing. If you have to mock up a bunch of stuff to test the outcome, so be it, but it's not wasted time. You're still doing up the typical arrange-action-assert deal, and you'll be able to read that later if you need to.Get back to your HTTP rootsASP.NET Webforms did a reasonably decent job at abstracting us away from the stateless nature of the Web. A lot of people criticize it, but I think it all worked pretty well. These days, with MVC, jQuery, REST services, and what not, we've gone back to thinking about the wire. The nuts and bolts passing between our Web browser and server matters. This doesn't make things harder, in my opinion, it makes them easier. There is something incredibly freeing about how we approach development of Web apps now. HTTP is a really simple protocol, and the stuff we push through it, in particular HTML and JSON, are pretty simple too. The debugging points are really easy to trap and trace.Premature optimization is prematureI'll go back to the data thing for a moment. I've been known to look at a particular action or use case and stress about the number of calls that are made to the database. I'm not suggesting that it's a bad thing to keep these in mind, but if you worry about it outside of the context of the actual impact, you're wasting time. For example, I query the database for last read times in a forum separately of the user and the list of forums. The impact on performance barely exists. If I put it under load, exceeding the kind of load I expect, it still barely has an impact. Then consider it only counts for logged in users. The context of this "inefficient" action is that it doesn't matter. Did I mention I won't be Facebook?Solve your own problems firstThis is another trap I've fallen into. I've often thought about what other people might need for some feature or aspect of the app. In other words, I was willing to make design decisions based on non-existent data. How stupid is that? When I decided to truly open source this thing, building for myself first was a stated design goal. This app has to server the audiences of CoasterBuzz, MouseZoom and other sites first. In this development scenario, you don't have access to mountains of usability studies or user focus groups. You have to start with what you know.I'm sure there are other points I could make too. It has been a lot of fun to work on, and I look forward to evolving the UI as time goes on. That's where I hope to see more magic in the future.

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  • Serialize WPF component using XamlWriter without default constructor

    - by mizipzor
    Ive found out that you can serialize a wpf component, in my example a FixedDocument, using the XamlWriter and a MemoryStream: FixedDocument doc = GetDocument(); MemoryStream stream = new MemoryStream(); XamlWriter.Save(doc, stream); And then to get it back: stream.Seek(0, SeekOrigin.Begin); FixedDocument result = (FixedDocument)XamlReader.Load(stream); return result; However, now I need to be able to serialize a DocumentPage as well. Which lacks a default constructor which makes the XamlReader.Load call throw an exception. Is there a way to serialize a wpf component without a default constructor?

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  • Optimizing AES modes on Solaris for Intel Westmere

    - by danx
    Optimizing AES modes on Solaris for Intel Westmere Review AES is a strong method of symmetric (secret-key) encryption. It is a U.S. FIPS-approved cryptographic algorithm (FIPS 197) that operates on 16-byte blocks. AES has been available since 2001 and is widely used. However, AES by itself has a weakness. AES encryption isn't usually used by itself because identical blocks of plaintext are always encrypted into identical blocks of ciphertext. This encryption can be easily attacked with "dictionaries" of common blocks of text and allows one to more-easily discern the content of the unknown cryptotext. This mode of encryption is called "Electronic Code Book" (ECB), because one in theory can keep a "code book" of all known cryptotext and plaintext results to cipher and decipher AES. In practice, a complete "code book" is not practical, even in electronic form, but large dictionaries of common plaintext blocks is still possible. Here's a diagram of encrypting input data using AES ECB mode: Block 1 Block 2 PlainTextInput PlainTextInput | | | | \/ \/ AESKey-->(AES Encryption) AESKey-->(AES Encryption) | | | | \/ \/ CipherTextOutput CipherTextOutput Block 1 Block 2 What's the solution to the same cleartext input producing the same ciphertext output? The solution is to further process the encrypted or decrypted text in such a way that the same text produces different output. This usually involves an Initialization Vector (IV) and XORing the decrypted or encrypted text. As an example, I'll illustrate CBC mode encryption: Block 1 Block 2 PlainTextInput PlainTextInput | | | | \/ \/ IV >----->(XOR) +------------->(XOR) +---> . . . . | | | | | | | | \/ | \/ | AESKey-->(AES Encryption) | AESKey-->(AES Encryption) | | | | | | | | | \/ | \/ | CipherTextOutput ------+ CipherTextOutput -------+ Block 1 Block 2 The steps for CBC encryption are: Start with a 16-byte Initialization Vector (IV), choosen randomly. XOR the IV with the first block of input plaintext Encrypt the result with AES using a user-provided key. The result is the first 16-bytes of output cryptotext. Use the cryptotext (instead of the IV) of the previous block to XOR with the next input block of plaintext Another mode besides CBC is Counter Mode (CTR). As with CBC mode, it also starts with a 16-byte IV. However, for subsequent blocks, the IV is just incremented by one. Also, the IV ix XORed with the AES encryption result (not the plain text input). Here's an illustration: Block 1 Block 2 PlainTextInput PlainTextInput | | | | \/ \/ AESKey-->(AES Encryption) AESKey-->(AES Encryption) | | | | \/ \/ IV >----->(XOR) IV + 1 >---->(XOR) IV + 2 ---> . . . . | | | | \/ \/ CipherTextOutput CipherTextOutput Block 1 Block 2 Optimization Which of these modes can be parallelized? ECB encryption/decryption can be parallelized because it does more than plain AES encryption and decryption, as mentioned above. CBC encryption can't be parallelized because it depends on the output of the previous block. However, CBC decryption can be parallelized because all the encrypted blocks are known at the beginning. CTR encryption and decryption can be parallelized because the input to each block is known--it's just the IV incremented by one for each subsequent block. So, in summary, for ECB, CBC, and CTR modes, encryption and decryption can be parallelized with the exception of CBC encryption. How do we parallelize encryption? By interleaving. Usually when reading and writing data there are pipeline "stalls" (idle processor cycles) that result from waiting for memory to be loaded or stored to or from CPU registers. Since the software is written to encrypt/decrypt the next data block where pipeline stalls usually occurs, we can avoid stalls and crypt with fewer cycles. This software processes 4 blocks at a time, which ensures virtually no waiting ("stalling") for reading or writing data in memory. Other Optimizations Besides interleaving, other optimizations performed are Loading the entire key schedule into the 128-bit %xmm registers. This is done once for per 4-block of data (since 4 blocks of data is processed, when present). The following is loaded: the entire "key schedule" (user input key preprocessed for encryption and decryption). This takes 11, 13, or 15 registers, for AES-128, AES-192, and AES-256, respectively The input data is loaded into another %xmm register The same register contains the output result after encrypting/decrypting Using SSSE 4 instructions (AESNI). Besides the aesenc, aesenclast, aesdec, aesdeclast, aeskeygenassist, and aesimc AESNI instructions, Intel has several other instructions that operate on the 128-bit %xmm registers. Some common instructions for encryption are: pxor exclusive or (very useful), movdqu load/store a %xmm register from/to memory, pshufb shuffle bytes for byte swapping, pclmulqdq carry-less multiply for GCM mode Combining AES encryption/decryption with CBC or CTR modes processing. Instead of loading input data twice (once for AES encryption/decryption, and again for modes (CTR or CBC, for example) processing, the input data is loaded once as both AES and modes operations occur at in the same function Performance Everyone likes pretty color charts, so here they are. I ran these on Solaris 11 running on a Piketon Platform system with a 4-core Intel Clarkdale processor @3.20GHz. Clarkdale which is part of the Westmere processor architecture family. The "before" case is Solaris 11, unmodified. Keep in mind that the "before" case already has been optimized with hand-coded Intel AESNI assembly. The "after" case has combined AES-NI and mode instructions, interleaved 4 blocks at-a-time. « For the first table, lower is better (milliseconds). The first table shows the performance improvement using the Solaris encrypt(1) and decrypt(1) CLI commands. I encrypted and decrypted a 1/2 GByte file on /tmp (swap tmpfs). Encryption improved by about 40% and decryption improved by about 80%. AES-128 is slighty faster than AES-256, as expected. The second table shows more detail timings for CBC, CTR, and ECB modes for the 3 AES key sizes and different data lengths. » The results shown are the percentage improvement as shown by an internal PKCS#11 microbenchmark. And keep in mind the previous baseline code already had optimized AESNI assembly! The keysize (AES-128, 192, or 256) makes little difference in relative percentage improvement (although, of course, AES-128 is faster than AES-256). Larger data sizes show better improvement than 128-byte data. Availability This software is in Solaris 11 FCS. It is available in the 64-bit libcrypto library and the "aes" Solaris kernel module. You must be running hardware that supports AESNI (for example, Intel Westmere and Sandy Bridge, microprocessor architectures). The easiest way to determine if AES-NI is available is with the isainfo(1) command. For example, $ isainfo -v 64-bit amd64 applications pclmulqdq aes sse4.2 sse4.1 ssse3 popcnt tscp ahf cx16 sse3 sse2 sse fxsr mmx cmov amd_sysc cx8 tsc fpu 32-bit i386 applications pclmulqdq aes sse4.2 sse4.1 ssse3 popcnt tscp ahf cx16 sse3 sse2 sse fxsr mmx cmov sep cx8 tsc fpu No special configuration or setup is needed to take advantage of this software. Solaris libraries and kernel automatically determine if it's running on AESNI-capable machines and execute the correctly-tuned software for the current microprocessor. Summary Maximum throughput of AES cipher modes can be achieved by combining AES encryption with modes processing, interleaving encryption of 4 blocks at a time, and using Intel's wide 128-bit %xmm registers and instructions. References "Block cipher modes of operation", Wikipedia Good overview of AES modes (ECB, CBC, CTR, etc.) "Advanced Encryption Standard", Wikipedia "Current Modes" describes NIST-approved block cipher modes (ECB,CBC, CFB, OFB, CCM, GCM)

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  • XML documentation to context sensitive help

    - by Yonas
    These days a number of commercial and open source tools have been developed for this purpose. However(unfortunately), non of them meet my requirement for specific problem I am dealing with. Currently, I am working on a project that exposes a different classes and functions to user as scripting interface. the user can use the objects from custom scripting interface and call methods to solve some specific problem. The problem I am facing is users of my classes need some sort of documentation in order to write their script efficiently. To address this problem am planing to use the compiler generated XML file to provide context sensitive help, which allows users to mouse over on any of the controls and corresponding methods from the GUI and read the reference documentation of the class/method. Now ... here are my questions: Can I get the sample source code? Can any one give me someone point me to some sort of best approach to address the problem?

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  • Fine tune some SQL called multiple times

    - by Carl
    Hi all, I currently have an SQL query which is currently called multiple times like this (pseudo code): foreach(KeyValuePair kvp in someMapList) { select col1 from table where col2 = kvp.key and col3 = kvp.value; //do some processing on the returned value } The above could obviously call the database a large number of times if it is a big list of pairs. Can anyone think of a more efficient piece of SQL which could essentially return a list of specific values based on a list of two unique pieces of information so that the processing can be done in bulk? One obvious one would be to build up a big piece of SQL with ORs but this would probably be quite inefficient? Thanks Carl

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  • Can I have conditional construction of classes when using IoC.Resolve ?

    - by Corpsekicker
    I have a service class which has overloaded constructors. One constructor has 5 parameters and the other has 4. Before I call, var service = IoC.Resolve<IService>(); I want to do a test and based on the result of this test, resolve service using a specific constructor. In other words, bool testPassed = CheckCertainConditions(); if (testPassed) { //Resolve service using 5 paramater constructor } else { //Resolve service using 4 parameter constructor //If I use 5 parameter constructor under these conditions I will have epic fail. } Is there a way I can specify which one I want to use?

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  • C# unit test code questions

    - by 5YrsLaterDBA
    We start use C# build-in unit test functionality. I have VisualStudio 2008 created unit test code for me. I have few question above the generated code. Following are code I copied from the generated file: #region Additional test attributes // //You can use the following additional attributes as you write your tests: // //Use ClassInitialize to run code before running the first test in the class //[ClassInitialize()] //public static void MyClassInitialize(TestContext testContext) //{ //} // //Use ClassCleanup to run code after all tests in a class have run //[ClassCleanup()] //public static void MyClassCleanup() //{ //} // //Use TestInitialize to run code before running each test //[TestInitialize()] //public void MyTestInitialize() //{ //} // //Use TestCleanup to run code after each test has run //[TestCleanup()] //public void MyTestCleanup() //{ //} // #endregion If I need the initialize and cleanup methods, do I need to remove those "My" from the method name when I enable them? //Use ClassInitialize to run code before running the first test in the class //[ClassInitialize()] //public static void MyClassInitialize(TestContext testContext) //{ //} Do I need to call the "MyClassInitialize" method somewhere before running the first test or it will be called automatically before other methods are called. Similar questions for other three methods, are they called automatically at right time frame?

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  • Convert sqlalchemy row object to python dict

    - by Anurag Uniyal
    or a simple way to iterate over columnName, value pairs? My version of sqlalchemy is 0.5.6 Here is the sample code where I tried using dict(row), but it throws exception , TypeError: 'User' object is not iterable import sqlalchemy from sqlalchemy import * from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.orm import sessionmaker print "sqlalchemy version:",sqlalchemy.__version__ engine = create_engine('sqlite:///:memory:', echo=False) metadata = MetaData() users_table = Table('users', metadata, Column('id', Integer, primary_key=True), Column('name', String), ) metadata.create_all(engine) class User(declarative_base()): __tablename__ = 'users' id = Column(Integer, primary_key=True) name = Column(String) def __init__(self, name): self.name = name Session = sessionmaker(bind=engine) session = Session() user1 = User("anurag") session.add(user1) session.commit() # uncommenting next line throws exception 'TypeError: 'User' object is not iterable' #print dict(user1) # this one also throws 'TypeError: 'User' object is not iterable' for u in session.query(User).all(): print dict(u) Running this code on my system outputs: sqlalchemy version: 0.5.6 Traceback (most recent call last): File "untitled-1.py", line 37, in <module> print dict(u) TypeError: 'User' object is not iterable

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  • Protecting against transaction concurency (Transaction type; Transaction IsolationLevel)

    - by Vytas999
    Middle-tier component will execute the data access routines in application. The component will call several SQL Server stored procedures to perform database updates. All of these procedure calls run under the control of a single transaction. The code for the middle-tier will implement the following objects: SqlCommand comm = connection.CreateCommand(); SqlTransaction trans; How i must add code to component to specify the highest possible level of protection against such errors(two users try to update the same data concurrently).

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  • confused about python decorators

    - by nbv4
    I have a class that has an output() method which returns a matplotlib Figure instance. I have a decorator I wrote that takes that fig instance and turns it into a Django response object. My decorator looks like this: class plot_svg(object): def __init__(self, view): self.view = view def __call__(self, *args, **kwargs): print args, kwargs fig = self.view(*args, **kwargs) canvas=FigureCanvas(fig) response=HttpResponse(content_type='image/svg+xml') canvas.print_svg(response) return response and this is how it was being used: def as_avg(self): return plot_svg(self.output)() The only reason I has it that way instead of using the "@" syntax is because when I do it with the "@": @plot_svg def as_svg(self): return self.output() I get this error: as_svg() takes exactly 1 argument (0 given) I'm trying to 'fix' this by putting it in the "@" syntax but I can't figure out how to get it working. I'm thinking it has something to do with self not getting passed where it's supposed to...

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  • MTU mismatch between GetIfEntry and netsh

    - by ChrisJ
    I'm working on pseudo-transport layer software that runs over UDP, providing reliable connection-oriented transmission, as an alternative to TCP. In order to maximize network efficiency, we query the MTU of the "best" network adapter upon initialization. MIB_IFROW row = {0}; row.dwIndex = dwBestIfIndex; dwRes = GetIfEntry(&row); Searching online I found that you can use the following netsh commands to query for this same value, from a command prompt (not a C++ API) netsh interface ipv4 show interfaces netsh interface ipv4 show subinterfaces The troubling issue is that while row.dwMtu may be set to 1500, snooping the network traffic on the sending laptop shows that our packets are fragmented into 1300 byte packets. netsh also reports that the MTU is 1300. Clearly the value reported by netsh command is the actual used values. Anyone know what API I can call to get the same values as netsh?

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  • EMail Signing (Outlook) Using Smartcard Minidriver [Windows]

    - by Baget
    Hi I'm developing a Smart card Minidriver and I'm trying to Sign an Email using Outlook 2007. I have implemented all of the necessary functions in the minidriver. I'm able to create a "Smartcard User" certificate and save it and it's private key on the smartcard (using Microsoft Certificate Services via the Minidriver). When I try to sign an EMail via Outlook I'm getting Error Message (Internal Error), the last call to the minidriver is for ReadFile with "cmapfile" When I try to sign an EMail via Outlook with a difference non-smartcard certificate it's work fine. When I try to sign a Data using CryptoAPI (based on Windows SDK Sample) it's working fine. I'm using Windows 7. someone got any idea how to debug this issue? I tried to enable the CAPI2 eventlog, it don't give me any good information.

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  • Core Location Best Placement and User Interruption

    - by b.dot
    Hi All, My application uses Core Location in three different views. It's working perfectly. In my first view, I subclass the CLLocationManager and use protocol methods for location updates to my calling class. Before I install the framework and code in my other classes, I was wondering: Is the protocol method the best way? What happens to the Core Location execution if the user exits the view or quits the app while it's trying to get a location fix? Is the location task terminated with the GPS system turned off immediately? If the user simply switches to another view, is it OK to assume that I can start Core Location in the next view without regard to the last? Where should the first update location call be placed. Should the application delegate instantiate the CLLocation Manager class using protocol so that it can update any of the views chosen or should each class instantiate the manager. Any feedback would be appreciated. Thanks.

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