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  • CodeGolf: Brothers

    - by John McClane
    Hi guys, I just finished participating in the 2009 ACM ICPC Programming Conest in the Latinamerican Finals. These questions were for Brazil, Bolivia, Chile, etc. My team and I could only finish two questions out of the eleven (not bad I think for the first try). Here's one we could finish. I'm curious to seeing any variations to the code. The question in full: ps: These questions can also be found on the official ICPC website available to everyone. In the land of ACM ruled a greeat king who became obsessed with order. The kingdom had a rectangular form, and the king divided the territory into a grid of small rectangular counties. Before dying the king distributed the counties among his sons. The king was unaware of the rivalries between his sons: The first heir hated the second but not the rest, the second hated the third but not the rest, and so on...Finally, the last heir hated the first heir, but not the other heirs. As soon as the king died, the strange rivaly among the King's sons sparked off a generalized war in the kingdom. Attacks only took place between pairs of adjacent counties (adjacent counties are those that share one vertical or horizontal border). A county X attacked an adjacent county Y whenever X hated Y. The attacked county was always conquered. All attacks where carried out simultanously and a set of simultanous attacks was called a battle. After a certain number of battles, the surviving sons made a truce and never battled again. For example if the king had three sons, named 0, 1 and 2, the figure below shows what happens in the first battle for a given initial land distribution: INPUT The input contains several test cases. The first line of a test case contains four integers, N, R, C and K. N - The number of heirs (2 <= N <= 100) R and C - The dimensions of the land. (2 <= R,C <= 100) K - Number of battles that are going to take place. (1 <= K <= 100) Heirs are identified by sequential integers starting from zero. Each of the next R lines contains C integers HeirIdentificationNumber (saying what heir owns this land) separated by single spaces. This is to layout the initial land. The last test case is a line separated by four zeroes separated by single spaces. (To exit the program so to speak) Output For each test case your program must print R lines with C integers each, separated by single spaces in the same format as the input, representing the land distribution after all battles. Sample Input: Sample Output: 3 4 4 3 2 2 2 0 0 1 2 0 2 1 0 1 1 0 2 0 2 2 2 0 0 1 2 0 0 2 0 0 0 1 2 2 Another example: Sample Input: Sample Output: 4 2 3 4 1 0 3 1 0 3 2 1 2 2 1 2

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  • How can I use Web Services Core to send a complex type as a parameter to a SOAP API method

    - by Matthew Brindley
    I don't do much Cocoa programming, so I'm probably missing something obvious, so please excuse the basic question. I have a SOAP method that expects a complex type as a paramater. Here's some WSDL: <s:element name="SaveTestResult"> <s:complexType> <s:sequence> <s:element minOccurs="0" maxOccurs="1" name="result" type="tns:TestItemResponse" /> </s:sequence> </s:complexType> </s:element> Here's the definition of the complex type "TestItemResponse": <s:complexType name="TestItemResponse"> <s:sequence> <s:element minOccurs="1" maxOccurs="1" name="TestItemRequestId" type="s:int" /> <s:element minOccurs="1" maxOccurs="1" name="ExternalId" type="s:int" /> <s:element minOccurs="0" maxOccurs="1" name="ApiId" type="s:string" /> <s:element minOccurs="0" maxOccurs="1" name="InboxGuid" type="s:string" /> <s:element minOccurs="0" maxOccurs="1" name="SpamResult" type="tns:SpamResult" /> <s:element minOccurs="0" maxOccurs="1" name="ResultImageSet" type="tns:ResultImageSet" /> <s:element minOccurs="1" maxOccurs="1" name="ExclusiveUseMailAccountId" type="s:int" /> <s:element minOccurs="1" maxOccurs="1" name="State" type="tns:TestItemResponseState" /> <s:element minOccurs="0" maxOccurs="1" name="ErrorShortDescription" type="s:string" /> <s:element minOccurs="0" maxOccurs="1" name="ErrorFullDescription" type="s:string" /> </s:sequence> </s:complexType> I've been using Web Services Core to call a SOAP API method that requires a simple string param, that works great. That same method returns a complex type which WSC converted into nested NSDictionaries, so no problems there. So I assumed I'd be able to convert my local TestItemResponse class into an NSDictionary and then use that as the complex type param. It almost worked, but unfortunately WSC set the object's type as "Dictionary", instead of "TestItemResponse", and the server complained. <TestItemResponse xsi:type=\"SOAP-ENC:Dictionary\"> <ErrorFullDescription xsi:type=\"xsd:string\">foo</ErrorFullDescription> ... I can't seem to find anything that allows you to override the type WSC assigns to the element in the SOAP XML. I've been using code adapted from here, I'm happy to list it, it's just quite long and this is already the longest SO question I've ever posted.

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  • Rail test case fixtures not loading

    - by Deano
    Rails appears to not be loading any fixtures for unit or functional tests. I have a simple 'products.yml' that parses and appears correct: ruby: title: Programming Ruby 1.9 description: Ruby is the fastest growing and most exciting dynamic language out there. If you need to get working programs delivered fast, you should add Ruby to your toolbox. price: 49.50 image_url: ruby.png My controller functional test begins with: require 'test_helper' class ProductsControllerTest < ActionController::TestCase fixtures :products setup do @product = products(:one) @update = { :title => 'Lorem Ipsum' , :description => 'Wibbles are fun!' , :image_url => 'lorem.jpg' , :price => 19.95 } end According to the book, Rails should "magically" load the fixtures (as my test_helper.rb has fixtures :all in it. I also added the explicit fixtures load (seen above). Yes Rails complains: user @ host ~/Dropbox/Rails/depot > rake test:functionals (in /Somewhere/Users/user/Dropbox/Rails/depot) /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby -Ilib:test "/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/rake-0.8.3/lib/rake/rake_test_loader.rb" "test/functional/products_controller_test.rb" Loaded suite /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/rake-0.8.3/lib/rake/rake_test_loader Started EEEEEEE Finished in 0.062506 seconds. 1) Error: test_should_create_product(ProductsControllerTest): NoMethodError: undefined method `products' for ProductsControllerTest:Class /test/functional/products_controller_test.rb:7 2) Error: test_should_destroy_product(ProductsControllerTest): NoMethodError: undefined method `products' for ProductsControllerTest:Class /test/functional/products_controller_test.rb:7 ... I did come across the other Rails test fixture question http://stackoverflow.com/questions/1547634/rails-unit-testing-doesnt-load-fixtures, but that leads to a plugin issue (something to do with the order of loading fixtures). BTW, I am developing on Mac OS X 10.6 with Rail 2.3.5 and Ruby 1.8.7, no additional plugins (beyond the base install). Any pointers on how to debug, why the magic of Rails appears to be failing here? Is it a version problem? Can I trace code into the libraries and find the answer? There are so many "mixin" modules I can't find where the fixtures method really lives.

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  • How to merge a "branch" that isn't really a branch (wasn't created by an svn copy)

    - by MatrixFrog
    I'm working on a team with lots of people who are pretty unfamiliar with the concepts of version control systems, and are just kind of doing whatever seems to work, by trial and error. Someone created a "branch" from the trunk that is not ancestrally related to the trunk. My guess is it went something like this: They created a folder in branches. They checked out all the code from the trunk to somewhere on their desktop. They added all that code to the newly created folder as though it was a bunch of brand new files. So the repository isn't aware that all that code is actually just a copy of the trunk. When I look at the history of that branch in TortoiseSVN, and uncheck the "Stop on copy/rename" box, there is no revision that has the trunk (or any other path) under the "Copy from path" column. Then they made lots of changes on their "branch". Meanwhile, others were making lots of changes on the trunk. We tried to do a merge and of course it doesn't work. Because, the trunk and the fake branch are not ancestrally related. I can see only two ways to resolve this: Go through the logs on the "branch", look at every change that was made, and manually apply each change to the trunk. Go through the logs on the trunk, look at every change that was made between revision 540 (when the "branch" was created) and HEAD, and manually apply each change to the "branch". This involves 7 revisions one way or 11 revisions the other way, so neither one is really that terrible. But is there any way to cause the repository to "realize" that the branch really IS ancestrally related even though it was created incorrectly, so that we can take advantage of the built-in merging functionality in Eclipse/TortoiseSVN? (You may be wondering: Why did your company hire these people and allow them to access the SVN repository without making sure they knew how to use it properly first?! We didn't -- this is a school assignment, which is a collaboration between two different classes -- the ones in the lower class were given a very quick hand-wavey "overview" of SVN which didn't really teach them anything. I've asked everyone in the group to please PLEASE read the svn book, and I'll make sure we (the slightly more experienced half of the team) keep a close eye on the repository to ensure this doesn't happen again.)

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  • Offline backup synchronization

    - by Pavan Kumar
    There is a Central Server running Windows Server 2003 and SQL Server 2005 and there are 7 client machines situated in various places and has XP Pro & SQL Server 2005 installed in all of them. They are not interconnected so they are physically seperate. One person goes to each of these centers maybe twice a month and takes the backup (Full database consisting of mdf and ldf files) with a pen drive and brings it to the Central server which contains the central database holding same schema as all the other client databases. I need to synchronize each backup database (belonging to different centers) one by one to update the existing data or inserting new data in the central database . The solution i got was Replication. The pendrive is brought to central server consisting of 7 instances of the databases and then the databases is attached to the central server one by one to the same SQL Server where the central database exists. Then my idea was to replicate the backup database one by one i.e using single subscription (Central Database) and multiple publication ( i.e 7 instances of databases in my case) toplogy by performing replication locally (i.e in the same machine). So i tried to develop a UI in C# .Net to programatically run the Transactional Replication with push subscription using RMO Programming (which is incomplete as of now because there is no point in developing when you already know it is not the solution). Transactional Replication can either be set to initialize with a snapshot or without a snapshot. If i go for the first option i.e with a snapshot , the data whatever is present in Central Database is overwritten by the new data . So the data present initially in the central database is lost. If i try to initialize without snapshot , no data (the data already has the updated and new data) will be sent from the backup database to server. The replication will work in a scenario where any incremental changes is done only after you set the replication . So the initial data whatever was present in the backup database when setting up the replication will not be replicated when running the snapshot agent for the first time to synchronize. Only changes in the backup database thereafter will be reflected to the central database .(Remember I am not going to insert new data or make any changes to the backup database after i attach it to the Central Server. ) So this solution is not feasible. I want a solution for synchronizing from one client database to central database present in the same machine using C#.NET. If you can provide me small example maybe with two databases(with same schema) DB1(Client) to DB2(Server) consisting of one or two tables it will be very helpful. The synchronization is not bidirectional.I want to only update existing data or insert new data from DB1 to DB2 (DB2 may contain some data initially). Thanks and Regards Pavan

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  • What is a good dumbed-down, safe template system for PHP?

    - by Wilhelm
    (Summary: My users need to be able to edit the structure of their dynamically generated web pages without being able to do any damage.) Greetings, ladies and gentlemen. I am currently working on a service where customers from a specific demographic can create a specific type of web site and fill it with their own content. The system is written in PHP. Many of the users of this system wish to edit how their particular web site looks, or, more commonly, have a designer do it for them. Editing the CSS is fine and dandy, but sometimes that's not enough. Sometimes they want to shuffle the entire page structure around by editing the raw HTML of the dynamically created web pages. The templating system used by WordPress is, as far as I can see, perfect for my use. Except for one thing which is critically important. In addition to being able to edit how comments are displayed or where the menu goes, someone editing a template can have that template execute arbitrary PHP code. As the same codebase runs all these different sites, with all content in the same databse, allowing my users to run arbitrary code is clearly out of the question. So what I need, is a dumbed-down, idiot-proof templating system where my users can edit most of the page structure on their own, pulling in the dynamic sections wherever, without being able to even echo 1+1;. Observe the following psuedocode: <!DOCTYPE html> <title><!-- $title --></title> <!-- header() --> <!-- menu() --> <div>Some random custom crap added by the user.</div> <!-- page_content() --> That's the degree of power I'd like to grant my users. They don't need to do their own loops or calculations or anything. Just include my variables and functions and leave the rest to me. I'm sure I'm not the only person on the planet that needs something like this. Do you know of any ready-made templating systems I could use? Thanks in advance for your reply.

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  • Adding Icons next to items in Navigation Drawer

    - by DunriteJW
    I have been trying to figure this out for quite some time right now. I've looked all over this site and many others, and can't find anything that works. I simply want icons next to each item in my navigation drawer. I am currently using the method that Google's navigation drawer sample app uses. in the MainActivity.java I have the following: mColorTitles = getResources().getStringArray(R.array.colors_array); mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout); mDrawerList = (ListView) findViewById(R.id.left_drawer); mColorIcons = getResources().getStringArray(R.array.color_icons); adapter = new ArrayAdapter<String>(this, R.layout.drawer_list_item, mColorTitles); // set a custom shadow that overlays the main content when the drawer opens mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START); // set up the drawer's list view with items and click listener mDrawerList.setAdapter(adapter); mDrawerList.setOnItemClickListener(new DrawerItemClickListener()); my drawer_list_item.xml: <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/text1" android:layout_width="match_parent" android:layout_height="match_parent" android:textAppearance="?android:attr/textAppearanceListItemSmall" android:gravity="center_vertical" android:paddingLeft="5dp" android:paddingRight="16dp" android:textColor="#000" android:background="?android:attr/activatedBackgroundIndicator" android:minHeight="?android:attr/listPreferredItemHeightSmall"/> it currently just makes the navigation drawer display the color titles from the array. I have the icons that I want in another array, and they follow the exact same order as I want them associated with the colors. I just have no idea how to even begin inserting the icons from that array into the navigation items if it helps, here's what my arrays look like in my strings.xml (not full code) <string-array name="colors_array"> <item>Home</item> <item>Cherry</item> <item>Crimson</item> ... <array name="color_icons"> <item>@drawable/homeicon</item> <item>@drawable/cherryicon</item> <item>@drawable/crimsonicon</item> ... I've tried putting a drawable in the drawer_list_item, which works, but (of course) it always puts the same one in there. I could not think of a way to change it according to the color. I am relatively new to android programming, so if I am missing something simple, I'm sorry. If you could help me out, I would greatly appreciate it, as this is basically the last thing I need to do before I publish my application to the Play Store. Thanks in advance!

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  • Is it possible to change HANDLE that has been opened for synchronous I/O to be opened for asynchrono

    - by Martin Dobšík
    Dear all, Most of my daily programming work in Windows is nowadays around I/O operations of all kind (pipes, consoles, files, sockets, ...). I am well aware of different methods of reading and writing from/to different kinds of handles (Synchronous, asynchronous waiting for completion on events, waiting on file HANDLEs, I/O completion ports, and alertable I/O). We use many of those. For some of our applications it would be very useful to have only one way to treat all handles. I mean, the program may not know, what kind of handle it has received and we would like to use, let's say, I/O completion ports for all. So first I would ask: Let's assume I have a handle: HANDLE h; which has been received by my process for I/O from somewhere. Is there any easy and reliable way to find out what flags it has been created with? The main flag in question is FILE_FLAG_OVERLAPPED. The only way known to me so far, is to try to register such handle into I/O completion port (using CreateIoCompletionPort()). If that succeeds the handle has been created with FILE_FLAG_OVERLAPPED. But then only I/O completion port must be used, as the handle can not be unregistered from it without closing the HANDLE h itself. Providing there is an easy a way to determine presence of FILE_FLAG_OVERLAPPED, there would come my second question: Is there any way how to add such flag to already existing handle? That would make a handle that has been originally open for synchronous operations to be open for asynchronous. Would there be a way how to create opposite (remove the FILE_FLAG_OVERLAPPED to create synchronous handle from asynchronous)? I have not found any direct way after reading through MSDN and googling a lot. Would there be at least some trick that could do the same? Like re-creating the handle in same way using CreateFile() function or something similar? Something even partly documented or not documented at all? The main place where I would need this, is to determine the the way (or change the way) process should read/write from handles sent to it by third party applications. We can not control how third party products create their handles. Dear Windows gurus: help please! With regards Martin

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  • Good Secure Backups Developers at Home

    - by slashmais
    What is a good, secure, method to do backups, for programmers who do research & development at home and cannot afford to lose any work? Conditions: The backups must ALWAYS be within reasonably easy reach. Internet connection cannot be guaranteed to be always available. The solution must be either FREE or priced within reason, and subject to 2 above. Status Report This is for now only considering free options. The following open-source projects are suggested in the answers (here & elsewhere): BackupPC is a high-performance, enterprise-grade system for backing up Linux, WinXX and MacOSX PCs and laptops to a server's disk. Storebackup is a backup utility that stores files on other disks. mybackware: These scripts were developed to create SQL dump files for basic disaster recovery of small MySQL installations. Bacula is [...] to manage backup, recovery, and verification of computer data across a network of computers of different kinds. In technical terms, it is a network based backup program. AutoDL 2 and Sec-Bk: AutoDL 2 is a scalable transport independant automated file transfer system. It is suitable for uploading files from a staging server to every server on a production server farm [...] Sec-Bk is a set of simple utilities to securely back up files to a remote location, even a public storage location. rsnapshot is a filesystem snapshot utility for making backups of local and remote systems. rbme: Using rsync for backups [...] you get perpetual incremental backups that appear as full backups (for each day) and thus allow easy restore or further copying to tape etc. Duplicity backs directories by producing encrypted tar-format volumes and uploading them to a remote or local file server. [...] uses librsync, [for] incremental archives Other Possibilities: Using a Distributed Version Control System (DVCS) such as Git(/Easy Git), Bazaar, Mercurial answers the need to have the backup available locally. Use free online storage space as a remote backup, e.g.: compress your work/backup directory and mail it to your gmail account. Strategies See crazyscot's answer

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  • How to write this Linq SQL as a Dynamic Query (using strings)?

    - by Dr. Zim
    Skip to the "specific question" as needed. Some background: The scenario: I have a set of products with a "drill down" filter (Query Object) populated with DDLs. Each progressive DDL selection will further limit the product list as well as what options are left for the DDLs. For example, selecting a hammer out of tools limits the Product Sizes to only show hammer sizes. Current setup: I created a query object, sent it to a repository, and fed each option to a SQL "table valued function" where null values represent "get all products". I consider this a good effort, but far from DDD acceptable. I want to avoid any "programming" in SQL, hopefully doing everything with a repository. Comments on this topic would be appreciated. Specific question: How would I rewrite this query as a Dynamic Query? A link to something like 101 Linq Examples would be fantastic, but with a Dynamic Query scope. I really want to pass to this method the field in quotes "" for which I want a list of options and how many products have that option. from p in db.Products group p by p.ProductSize into g select new Category { PropertyType = g.Key, Count = g.Count() } Each DDL option will have "The selection (21)" where the (21) is the quantity of products that have that attribute. Upon selecting an option, all other remaining DDLs will update with the remaining options and counts. Edit: Additional notes: .OrderBy("it.City") // "it" refers to the entire record .GroupBy("City", "new(City)") // This produces a unique list of City .Select("it.Count()") //This gives a list of counts... getting closer .Select("key") // Selects a list of unique City .Select("new (key, count() as string)") // +1 to me LOL. key is a row of group .GroupBy("new (City, Manufacturer)", "City") // New = list of fields to group by .GroupBy("City", "new (Manufacturer, Size)") // Second parameter is a projection Product .Where("ProductType == @0", "Maps") .GroupBy("new(City)", "new ( null as string)")// Projection not available later? .Select("new (key.City, it.count() as string)")// GroupBy new makes key an object Product .Where("ProductType == @0", "Maps") .GroupBy("new(City)", "new ( null as string)")// Projection not available later? .Select("new (key.City, it as object)")// the it object is the result of GroupBy var a = Product .Where("ProductType == @0", "Maps") .GroupBy("@0", "it", "City") // This fails to group Product at all .Select("new ( Key, it as Product )"); // "it" is property cast though What I have learned so far is LinqPad is fantastic, but still looking for an answer. Eventually, completely random research like this will prevail I guess. LOL. Edit:

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  • Cases of companies taking IP rights of your own personal projects developed outside company time

    - by GSS
    Hi, I have heard of cases where a developer working for a company is also making his own personal projects in his own time, using his own equipment yet the company he works for tries to claim ownership for the project. I really find this annoying, and bang out of order. It should also be illegal. I am in this position (work for a company and working on my own systems - from small class libraries used to practise what I learn in my exam revision to a large commercial-scale system). While I don't know if the company will try to take ownership, all I know is they say they do not want a conflict of interest. Fair enough, my system is developed in my own time using my own equipment. They also say that work time should be for work only, which it is. Funny thing that as work is so boring, easy and slow that I have plenty of free time, which I wish I could spend on something productive - said system. The problem is, my company does not take hiring technical talent seriously. This is my first job, I am a junior coder (but my status/position doesn't really reflect what I can do), but I am the only developer. Likewise with the guy who controls Windows Server. As the contract does not say anything about taking ownership, I would assume they would. They would try to milk my success (I've made a good impression so I am sure they would). How can this be allowed? Are there any examples of this happening to any fellow Stacker here? It really makes my blood boil. What I find funny is that my company hardly has the expertise and resources to even be able to successfully run a project of my size. What I do at work is an ASP.NET application consisting of five pages, and even then there are flaws in the project. If I told them that they would also have to take responsibility for flaws in the project, then they would think twice! It's exactly because of this I save the best code for myself and at work I write rubbish code full of code smells. The company don't really care about error handling, as long as the business functionality works (ie a scheduled email sends, but there is no error handling). They'd think twice when they see the embarassment and business cost of a YSOD...

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  • Problem getting Java Streams in HP Tandem (Non-Stop)

    - by AndreaG
    Hi. We are porting a simple Java application between Tandem NonStop systems, from G-Series to H-Series. Java version is 1.5.0_02. When performing basic I/O tasks like getting output stream from or opening a client socket, we receive exceptions like java.io.IOException: Value out of range or java.net.SocketException: Value out of range ("value out of range" is Tandem native jargon for, well, quite everything I suppose). Has anybody got similar issues? i.e. I/O corruption while for example messing with JNI? I suppose there is something wrong with the system, but where might it be? Thank you. EDIT: adding snippets as requested sample snippet (a) - using Runtime.exec () (adapted) Properties envVars = new Properties(); Process p = r.exec("/bin/env"); envVars.load(p.getInputStream()); Stack trace (a): java.io.IOException: Value out of range (errno:4034) at java.io.FileInputStream.readBytes(Native Method) at java.io.FileInputStream.read(FileInputStream.java:194) at java.lang.UNIXProcess$DeferredCloseInputStream.read(UNIXProcess.java:221) at java.io.BufferedInputStream.read1(BufferedInputStream.java:254) at java.io.BufferedInputStream.read(BufferedInputStream.java:313) at sun.nio.cs.StreamDecoder$CharsetSD.readBytes(StreamDecoder.java:411) at sun.nio.cs.StreamDecoder$CharsetSD.implRead(StreamDecoder.java:453) at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:183) at java.io.InputStreamReader.read(InputStreamReader.java:167) at java.io.BufferedReader.fill(BufferedReader.java:136) at java.io.BufferedReader.readLine(BufferedReader.java:299) at java.io.BufferedReader.readLine(BufferedReader.java:362) at util.Environment.getVariables(Environment.java:39) Last line fails, and output gets redirected to console (!). sample snippet (b) - using HttpURLConnection: public WorkerThread (HttpURLConnection conn, String requestData, Logger logger) { this.conn = conn; ... } public void run () { OutputStream out = conn.getOutputStream (); } Stack trace (b): java.net.SocketException: Value out of range (errno:4034) at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) at java.net.Socket.connect(Socket.java:507) at sun.net.NetworkClient.doConnect(NetworkClient.java:155) at sun.net.www.http.HttpClient.openServer(HttpClient.java:365) at sun.net.www.http.HttpClient.openServer(HttpClient.java:477) at sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:280) at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:337) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:176) at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:736) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:162) at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:828) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:230) Case (a) can be avoided because it was a workaround for other issues with previous JRE version (!), but same behaviour with sockets is really nasty.

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  • Do you still limit line length in code?

    - by Noldorin
    This is a matter on which I would like to gauge the opinion of the community: Do you still limit the length of lines of code to a fixed maximum? This was certainly a convention of the past for many languages; one would typically cap the number of characters per line to a value such as 80 (and more recnetly 100 or 120 I believe). As far as I understand, the primary reasons for limiting line length are: Readability - You don't have to scroll over horizontally when you want to see the end of some lines. Printing - Admittedly (at least in my experience), most code that you are working on does not get printed out on paper, but by limiting the number of characters you can insure that formatting doesn't get messed up when printed. Past editors (?) - Not sure about this one, but I suspect that at some point in the distant past of programming, (at least some) text editors may have been based on a fixed-width buffer. I'm sure there are points that I am still missing out, so feel free to add to these... Now, when I tend to observe C or C# code nowadays, I often see a number of different styles, the main ones being: Line length capped to 80, 100, or even 120 characters. As far as I understand, 80 is the traditional length, but the longer ones of 100 and 120 have appeared because of the widespread use of high resolutions and widescreen monitors nowadays. No line length capping at all. This tends to be pretty horrible to read, and I don't see it too often, though it's certainly not too rare either. Inconsistent capping of line length. The length of some lines are limited to a fixed maximum (or even a maximum that changes depending on the file/location in code), while others (possibly comments) are not at all. My personal preference here (at least recently) has been to cap the line length to 100 in the Visual Studio editor. This means that in a decently sized window (on a non-widescreen monitor), the ends of lines are still fully visible. I can however see a few disadvantages in this, especially when you end up writing code that's indented 3 or 4 levels and then having to include a long string literal - though I often take this as a sign to refactor my code! In particular, I am curious what the C and C# coders (or anyone who uses Visual Studio for that matter) think about this point, though I would be interested in hearing anyone's thoughts on the subject. Edit Thanks for the all answers - I appreciate the variety of opinions here, all presenting sound reasons. Consensus does seem to be tipping in the direction of always (or almost always) limit the line length. Interestingly, it seems to be in various coding standards to limit the line length. Judging by some of the answers, both the Python and Google CPP guidelines set the limit at 80 chars. I haven't seen anything similar regarding C# or VB.NET, but I would be curious to see if there are ones anywhere.

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  • Efficiency of data structures in C99 (possibly affected by endianness)

    - by Ninefingers
    Hi All, I have a couple of questions that are all inter-related. Basically, in the algorithm I am implementing a word w is defined as four bytes, so it can be contained whole in a uint32_t. However, during the operation of the algorithm I often need to access the various parts of the word. Now, I can do this in two ways: uint32_t w = 0x11223344; uint8_t a = (w & 0xff000000) >> 24; uint8_t b = (w & 0x00ff0000) >> 16; uint8_t b = (w & 0x0000ff00) >> 8; uint8_t d = (w & 0x000000ff); However, part of me thinks that isn't particularly efficient. I thought a better way would be to use union representation like so: typedef union { struct { uint8_t d; uint8_t c; uint8_t b; uint8_t a; }; uint32_t n; } word32; Using this method I can assign word32 w = 0x11223344; then I can access the various parts as I require (w.a=11 in little endian). However, at this stage I come up against endianness issues, namely, in big endian systems my struct is defined incorrectly so I need to re-order the word prior to it being passed in. This I can do without too much difficulty. My question is, then, is the first part (various bitwise ands and shifts) efficient compared to the implementation using a union? Is there any difference between the two generally? Which way should I go on a modern, x86_64 processor? Is endianness just a red herring here? I could inspect the assembly output of course, but my knowledge of compilers is not brilliant. I would have thought a union would be more efficient as it would essentially convert to memory offsets, like so: mov eax, [r9+8] Would a compiler realise that is what happening in the bit-shift case above? If it matters, I'm using C99, specifically my compiler is clang (llvm). Thanks in advance.

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  • Zend Framework - Ruby on Rails has a screencast showing how to code a blog in 15 minutes. Does ZF ha

    - by Sootah
    Ruby on Rails has a screencast presentation they use to promote their framework that shows how to code a basic weblog system in 15 minutes with RoR. Does the Zend PHP Framework have a similar screencast/presentation/whatever demonstrating something similar? It doesn't have to be a blog specifically, but I would definitely like to find a presentation that shows some rapid application development using ZF. Where I'm coming from: I have been programming on and off for years now. I started out with QBASIC waaaaay back in the day making little programs (text adventure games, screensavers, simple little things). I then moved to C++ but never really did anything too impressive with it. Since then (probably 5 years or so now) I have started to use C# for my desktop development and PHP for my web development. I've made some pretty cool tools here and there, but am certainly not a professional programmer by any stretch of the term as it has always simply been a hobby of mine. Right now I have two major web applications that I will start work on shortly. (Like tomorrow, or later tonight ideally.. :) ) Both will be database-driven apps that will require user registration, the ability to manipulate data that is specific to their account (their posts, listings, user account details, etc), amongst other things. Currently I am evaluating different frameworks to help me develop these web apps more quickly. I've been looking at, and have heard good things about Ruby on Rails. Hulu and YellowPages.com using it is an obvious endorsement - Of course, I have heard about the scalability issues that it potentially has; but that shouldn't be an issue with what I am working on. I don't expect millions of users per day for either project. I am also seriously looking at the Zend Framework for my needs because I already have some experience with PHP. Ideally I would like to find a ZF screencast that shows an app being written quickly so that I have a roughly equal comparison between the two options I am exploring and can see first-hand how things get done in both. That said - I am not opposed to considering frameworks other than RoR or ZF. The only research I've done on the subject has been over the past couple of days so I am quite certain that there are other excellent options out there that I've not even looked at - or heard of. Of course, it'd be awesome if there is a rapid app dev presentation that I can watch for whatever else is suggested. So - Suggestions? Links to good screencasts that show rapid application development in other frameworks? Are there other PHP frameworks that I should be considering? (Ones that are easy to deploy would be ideal, so I don't have to purchase a dedicated server that I have full control over. I'd like to keep my hosting costs down assuming that it's reasonable) Thanks in advance! -Sootah

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  • Installing my sdist from PyPI puts the files in the wrong places

    - by Tartley
    Hey. My problem is that when I upload my Python package to PyPI, and then install it from there using pip, my app breaks because it installs my files into completely different locations than when I simply install the exact same package from a local sdist. Installing from the local sdist puts files on my system like this: /Python27/ Lib/ site-packages/ gloopy-0.1.alpha-py2.7.egg/ (egg and install info files) data/ (images and shader source) doc/ (html) examples/ (.py scripts that use the library) gloopy/ (source) This is much as I'd expect, and works fine (e.g. my source can find my data dir, because they lie next to each other, just like they do in development.) If I upload the same sdist to PyPI and then install it from there, using pip, then things look very different: /Python27/ data/ (images and shader source) doc/ (html) Lib/ site-packages/ gloopy-0.1.alpha-py2.7.egg/ (egg and install info files) gloopy/ (source files) examples/ (.py scripts that use the library) This doesn't work at all - my app can't find its data files, plus obviously it's a mess, polluting the top-level /python27 directory with all my junk. What am I doing wrong? How do I make the pip install behave like the local sdist install? Is that even what I should be trying to achieve? Details I have setuptools installed, and also distribute, and I'm calling distribute_setup.use_setuptools() WindowsXP, Python2.7. My development directory looks like this: /gloopy /data (image files and GLSL shader souce read at runtime) /doc (html files) /examples (some scripts to show off the library) /gloopy (the library itself) My MANIFEST.in mentions all the files I want to be included in the sdist, including everything in the data, examples and doc directories: recursive-include data *.* recursive-include examples *.py recursive-include doc/html *.html *.css *.js *.png include LICENSE.txt include TODO.txt My setup.py is quite verbose, but I guess the best thing is to include it here, right? I also includes duplicate references to the same data / doc / examples directories as are mentioned in the MANIFEST.in, because I understand this is required in order for these files to be copied from the sdist to the system during install. NAME = 'gloopy' VERSION= __import__(NAME).VERSION RELEASE = __import__(NAME).RELEASE SCRIPT = None CONSOLE = False def main(): import sys from pprint import pprint from setup_utils import distribute_setup from setup_utils.sdist_setup import get_sdist_config distribute_setup.use_setuptools() from setuptools import setup description, long_description = read_description() config = dict( name=name, version=version, description=description, long_description=long_description, keywords='', packages=find_packages(), data_files=[ ('examples', glob('examples/*.py')), ('data/shaders', glob('data/shaders/*.*')), ('doc', glob('doc/html/*.*')), ('doc/_images', glob('doc/html/_images/*.*')), ('doc/_modules', glob('doc/html/_modules/*.*')), ('doc/_modules/gloopy', glob('doc/html/_modules/gloopy/*.*')), ('doc/_modules/gloopy/geom', glob('doc/html/_modules/gloopy/geom/*.*')), ('doc/_modules/gloopy/move', glob('doc/html/_modules/gloopy/move/*.*')), ('doc/_modules/gloopy/shapes', glob('doc/html/_modules/gloopy/shapes/*.*')), ('doc/_modules/gloopy/util', glob('doc/html/_modules/gloopy/util/*.*')), ('doc/_modules/gloopy/view', glob('doc/html/_modules/gloopy/view/*.*')), ('doc/_static', glob('doc/html/_static/*.*')), ('doc/_api', glob('doc/html/_api/*.*')), ], classifiers=[ 'Development Status :: 1 - Planning', 'Intended Audience :: Developers', 'License :: OSI Approved :: BSD License', 'Operating System :: Microsoft :: Windows', 'Programming Language :: Python :: 2.7', ], # see classifiers http://pypi.python.org/pypi?:action=list_classifiers ) config.update(dict( author='Jonathan Hartley', author_email='[email protected]', url='http://bitbucket.org/tartley/gloopy', license='New BSD', ) ) if '--verbose' in sys.argv: pprint(config) setup(**config) if __name__ == '__main__': main()

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  • Java - How to make a set of JInternalFrame independant of each other?

    - by Amokrane
    Hello, I'm programming a short Paint program like and I'm trying to make an MDI architecture for it. To make that happen, I used JInternalFrame inside a JDesktopPane. Although I kind of obtain multiple frames, there are not really working properly. Basically, if I have 2 JInternalFrame I can draw only on the last one. The other one seems to be disabled. Here is a short video illustrating the problem. http://bit.ly/9ydiwM Here are some part of the code. Panneau.java public class Panneau extends JDesktopPane { /** La liste de fenêtres ouvertes */ private static ArrayList<Cadre> cadres; /** Le pannel comportant la liste des formes à dessiner*/ private Pannel pannel; /** La barre d'outils */ private ToolBox toolBox; public Panneau() { this.setLayout(new BorderLayout()); // Initialisations des listes de cadres cadres = new ArrayList<Cadre>(); // En haut ToolBox toolBox = new ToolBox(); this.add(toolBox, BorderLayout.NORTH); **// Intialisation de la première internal frame Cadre cadre = new Cadre(); this.add(cadre, BorderLayout.CENTER);** cadres.add(cadre); // Ajout du pannel à gauche pannel = new Pannel(); this.add(pannel, BorderLayout.WEST); } /** * Crée une nouvelle fenêtre de dessin * */ **public void createNewInternalFrame() { Cadre cadre = new Cadre(); this.add(cadre, BorderLayout.CENTER); cadres.add(cadre); }** } public class Cadre extends JInternalFrame { /** Largeur par d'une fenêtre interne */ private int width; /** Hauteur d'une fenêtre interne */ private int height; /** Titre d'une fenêtre interne */ private String title; /** Toile associée à la fenêtre interne */ private Toile toile; public Cadre() { width = 400; height = 400; title = "Form"; toile = new Toile(); this.setTitle(title); this.setSize(width, height); this.setEnabled(true); this.setResizable(true); this.setAutoscrolls(true); this.setClosable(true); this.setIconifiable(true); this.setDoubleBuffered(true); this.setContentPane(toile); this.setVisible(true); this.pack(); } } Basically, Panneau is the main Window that contains all the differents parts of the GUI. I can create as much JInternalFrame that I want, using : Panneau.createNewInternalFrame(). Toile is basically where I draw my shapes. Any idea ? Thanks

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  • What is the best python module skeleton code?

    - by user213060
    == Subjective Question Warning == Looking for well supported opinions or supporting evidence. Let us assume that skeleton code can be good. If you disagree with the very concept of module skeleton code then fine, but please refrain from repeating that opinion here. Many python IDE's will start you with a template like: print 'hello world' That's not enough... So here's my skeleton code to get this question started: My Module Skeleton, Short Version: #!/usr/bin/env python """ Module Docstring """ # ## Code goes here. # def test(): """Testing Docstring""" pass if __name__=='__main__': test() and, My Module Skeleton, Long Version: #!/usr/bin/env python # -*- coding: ascii -*- """ Module Docstring Docstrings: http://www.python.org/dev/peps/pep-0257/ """ __author__ = 'Joe Author ([email protected])' __copyright__ = 'Copyright (c) 2009-2010 Joe Author' __license__ = 'New-style BSD' __vcs_id__ = '$Id$' __version__ = '1.2.3' #Versioning: http://www.python.org/dev/peps/pep-0386/ # ## Code goes here. # def test(): """ Testing Docstring""" pass if __name__=='__main__': test() Notes: """ ===MODULE TYPE=== Since the vast majority of my modules are "library" types, I have constructed this example skeleton as such. For modules that act as the main entry for running the full application, you would make changes such as running a main() function instead of the test() function in __main__. ===VERSIONING=== The following practice, specified in PEP8, no longer makes sense: __version__ = '$Revision: 1.2.3 $' for two reasons: (1) Distributed version control systems make it neccessary to include more than just a revision number. E.g. author name and revision number. (2) It's a revision number not a version number. Instead, the __vcs_id__ variable is being adopted. This expands to, for example: __vcs_id__ = '$Id: example.py,v 1.1.1.1 2001/07/21 22:14:04 goodger Exp $' ===VCS DATE=== Likewise, the date variable has been removed: __date__ = '$Date: 2009/01/02 20:19:18 $' ===CHARACTER ENCODING=== If the coding is explicitly specified, then it should be set to the default setting of ascii. This can be modified if necessary (rarely in practice). Defaulting to utf-8 can cause anomalies with editors that have poor unicode support. """ There are a lot of PEPs that put forward coding style recommendations. Am I missing any important best practices? What is the best python module skeleton code? Update Show me any kind of "best" that you prefer. Tell us what metrics you used to qualify "best".

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  • How to merge an improperly created "branch" that isn't really a branch (wasn't created by an svn cop

    - by MatrixFrog
    I'm working on a team with lots of people who are pretty unfamiliar with the concepts of version control systems, and are just kind of doing whatever seems to work, by trial and error. Someone created a "branch" from the trunk that is not ancestrally related to the trunk. My guess is it went something like this: They created a folder in branches. They checked out all the code from the trunk to somewhere on their desktop. They added all that code to the newly created folder as though it was a bunch of brand new files. So the repository isn't aware that all that code is actually just a copy of the trunk. When I look at the history of that branch in TortoiseSVN, and uncheck the "Stop on copy/rename" box, there is no revision that has the trunk (or any other path) under the "Copy from path" column. Then they made lots of changes on their "branch". Meanwhile, others were making lots of changes on the trunk. We tried to do a merge and of course it doesn't work. Because, the trunk and the fake branch are not ancestrally related. I can see only two ways to resolve this: Go through the logs on the "branch", look at every change that was made, and manually apply each change to the trunk. Go through the logs on the trunk, look at every change that was made between revision 540 (when the "branch" was created) and HEAD, and manually apply each change to the "branch". This involves 7 revisions one way or 11 revisions the other way, so neither one is really that terrible. But is there any way to cause the repository to "realize" that the branch really IS ancestrally related even though it was created incorrectly, so that we can take advantage of the built-in merging functionality in Eclipse/TortoiseSVN? (You may be wondering: Why did your company hire these people and allow them to access the SVN repository without making sure they knew how to use it properly first?! We didn't -- this is a school assignment, which is a collaboration between two different classes -- the ones in the lower class were given a very quick hand-wavey "overview" of SVN which didn't really teach them anything. I've asked everyone in the group to please PLEASE read the svn book, and I'll make sure we (the slightly more experienced half of the team) keep a close eye on the repository to ensure this doesn't happen again.)

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  • What are the Tags Around Default iPhone Address Book People Phone Number Labels?

    - by rnistuk
    My question concerns markup that surrounds some of the default phone number labels in the Person entries of the Contact list on the iPhone. I have created an iPhone contact list address book entry for a person, "John Smith" with the following phone number entries: Mobile (604) 123-4567 iPhone (778) 123-4567 Home (604) 789-4561 Work (604) 456-7891 Main (604) 789-1234 megaphone (234) 567-8990 Note that the first five labels are default labels provided by the Contacts application and the last label, "megaphone", is a custom label. I wrote the following method to retrieve and display the labels and phone numbers for each person in the address book: -(void)displayPhoneNumbersForAddressBook { ABAddressBookRef book = ABAddressBookCreate(); CFArrayRef people = ABAddressBookCopyArrayOfAllPeople(book); ABRecordRef record = CFArrayGetValueAtIndex(people, 0); ABMultiValueRef multi = ABRecordCopyValue(record, kABPersonPhoneProperty); NSLog(@"---------" ); NSLog(@"displayPhoneNumbersForAddressBook" ); CFStringRef label, phone; for (CFIndex i = 0; i < ABMultiValueGetCount(multi); ++i) { label = ABMultiValueCopyLabelAtIndex(multi, i); phone = ABMultiValueCopyValueAtIndex(multi, i); NSLog(@"label: \"%@\" number: \"%@\"", (NSString*)label, (NSString*)phone); CFRelease(label); CFRelease(phone); } NSLog(@"---------" ); CFRelease(multi); CFRelease(people); CFRelease(book); } and here is the output for the address book entry that I entered: 2010-03-08 13:24:28.789 test2m[2479:207] --------- 2010-03-08 13:24:28.789 test2m[2479:207] displayPhoneNumbersForAddressBook 2010-03-08 13:24:28.790 test2m[2479:207] label: "_$!<Mobile>!$_" number: "(604) 123-4567" 2010-03-08 13:24:28.790 test2m[2479:207] label: "iPhone" number: "(778) 123-4567" 2010-03-08 13:24:28.791 test2m[2479:207] label: "_$!<Home>!$_" number: "(604) 789-4561" 2010-03-08 13:24:28.791 test2m[2479:207] label: "_$!<Work>!$_" number: "(604) 456-7891" 2010-03-08 13:24:28.792 test2m[2479:207] label: "_$!<Main>!$_" number: "(604) 789-1234" 2010-03-08 13:24:28.792 test2m[2479:207] label: "megaphone" number: "(234) 567-8990" 2010-03-08 13:24:28.793 test2m[2479:207] --------- What are the markup characters _$!< and >!$_ surrounding most, save for iPhone, of the default labels for? Can you point me to where in the "Address Book Programming Guide for iPhone OS" I can find the information? Thank you for your help.

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  • Is the Scala 2.8 collections library a case of "the longest suicide note in history" ?

    - by oxbow_lakes
    First note the inflammatory subject title is a quotation made about the manifesto of a UK political party in the early 1980s. This question is subjective but it is a genuine question, I've made it CW and I'd like some opinions on the matter. Despite whatever my wife and coworkers keep telling me, I don't think I'm an idiot: I have a good degree in mathematics from the University of Oxford and I've been programming commercially for almost 12 years and in Scala for about a year (also commercially). I have just started to look at the Scala collections library re-implementation which is coming in the imminent 2.8 release. Those familiar with the library from 2.7 will notice that the library, from a usage perspective, has changed little. For example... > List("Paris", "London").map(_.length) res0: List[Int] List(5, 6) ...would work in either versions. The library is eminently useable: in fact it's fantastic. However, those previously unfamiliar with Scala and poking around to get a feel for the language now have to make sense of method signatures like: def map[B, That](f: A => B)(implicit bf: CanBuildFrom[Repr, B, That]): That For such simple functionality, this is a daunting signature and one which I find myself struggling to understand. Not that I think Scala was ever likely to be the next Java (or /C/C++/C#) - I don't believe its creators were aiming it at that market - but I think it is/was certainly feasible for Scala to become the next Ruby or Python (i.e. to gain a significant commercial user-base) Is this going to put people off coming to Scala? Is this going to give Scala a bad name in the commercial world as an academic plaything that only dedicated PhD students can understand? Are CTOs and heads of software going to get scared off? Was the library re-design a sensible idea? If you're using Scala commercially, are you worried about this? Are you planning to adopt 2.8 immediately or wait to see what happens? Steve Yegge once attacked Scala (mistakenly in my opinion) for what he saw as its overcomplicated type-system. I worry that someone is going to have a field day spreading fud with this API (similarly to how Josh Bloch scared the JCP out of adding closures to Java). Note - I should be clear that, whilst I believe that Josh Bloch was influential in the rejection of the BGGA closures proposal, I don't ascribe this to anything other than his honestly-held beliefs that the proposal represented a mistake.

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  • How Can I create different selectors for accepting new connection in java NIO

    - by Deepak
    I want to write java tcp socket programming using java NIO. Its working fine. But I am using the same selector for accepting reading from and writing to the clients. How Can I create different selectors for accepting new connection in java NIO, reading and writing. Is there any online help. Actually when I am busy in reading or writing my selector uses more iterator. So If more number of clients are connected then performance of accepting new coneection became slow. But I donot want the accepting clients to be slow // Create a selector and register two socket channels Selector selector = null; try { // Create the selector selector = Selector.open(); // Create two non-blocking sockets. This method is implemented in // e173 Creating a Non-Blocking Socket. SocketChannel sChannel1 = createSocketChannel("hostname.com", 80); SocketChannel sChannel2 = createSocketChannel("hostname.com", 80); // Register the channel with selector, listening for all events sChannel1.register(selector, sChannel1.validOps()); sChannel2.register(selector, sChannel1.validOps()); } catch (IOException e) { } // Wait for events while (true) { try { // Wait for an event selector.select(); } catch (IOException e) { // Handle error with selector break; } // Get list of selection keys with pending events Iterator it = selector.selectedKeys().iterator(); // Process each key at a time while (it.hasNext()) { // Get the selection key SelectionKey selKey = (SelectionKey)it.next(); // Remove it from the list to indicate that it is being processed it.remove(); try { processSelectionKey(selKey); } catch (IOException e) { // Handle error with channel and unregister selKey.cancel(); } } } public void processSelectionKey(SelectionKey selKey) throws IOException { // Since the ready operations are cumulative, // need to check readiness for each operation if (selKey.isValid() && selKey.isConnectable()) { // Get channel with connection request SocketChannel sChannel = (SocketChannel)selKey.channel(); boolean success = sChannel.finishConnect(); if (!success) { // An error occurred; handle it // Unregister the channel with this selector selKey.cancel(); } } if (selKey.isValid() && selKey.isReadable()) { // Get channel with bytes to read SocketChannel sChannel = (SocketChannel)selKey.channel(); // See e174 Reading from a SocketChannel } if (selKey.isValid() && selKey.isWritable()) { // Get channel that's ready for more bytes SocketChannel sChannel = (SocketChannel)selKey.channel(); } } Thanks Deepak

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  • Is my understanding of "select distinct" correct?

    - by paxdiablo
    We recently discovered a performance problem with one of our systems and I think I have the fix but I'm not certain my understanding is correct. In simplest form, we have a table blah into which we accumulate various values based on a key field. The basic form is: recdate date rectime time system varchar(20) count integer accum1 integer accum2 integer There are a lot more accumulators than that but they're all of the same form. The primary key is made up of recdate, rectime and system. As values are collected to the table, the count for a given recdate/rectime/system is incremented and the values for that key are added to the accumulators. That means the averages can be obtained by using accumN / count. Now we also have a view over that table specified as follows: create view blah_v ( recdate, rectime, system, count, accum1, accum2 ) as select distinct recdate, rectime, system, count, value (case when count > 0 then accum1 / count end, 0), value (case when count > 0 then accum2 / count end, 0) from blah; In other words, the view gives us the average value of the accumulators rather than the sums. It also makes sure we don't get a divide-by-zero in those cases where the count is zero (these records do exist and we are not allowed to remove them so don't bother telling me they're rubbish - you're preaching to the choir). We've noticed that the time difference between doing: select distinct recdate from XX varies greatly depending on whether we use the table or the view. I'm talking about the difference being 1 second for the table and 27 seconds for the view (with 100K rows). We actually tracked it back to the select distinct. What seems to be happening is that the DBMS is actually loading all the rows in and sorting them so as to remove duplicates. That's fair enough, it's what we stupidly told it to do. But I'm pretty sure the fact that the view includes every component of the primary key means that it's impossible to have duplicates anyway. We've validated the problem since, if we create another view without the distinct, it performs at the same speed as the underlying table. I just wanted to confirm my understanding that a select distinct can not have duplicates if it includes all the primary key components. If that's so, then we can simply change the view appropriately.

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  • Computation on db data then list them using either SimpleCursorAdapter or ArrayAdapter

    - by kc2uno
    Hi all, I juststarted programming in android a few weeks ago, so I am not entirely sure how to deal with listing values. Please help me out! I have some questions regarding displaying data sets from db in a list. Currently I have a cursor returned by my db points to a list of rows and I want display 2 columns values in a single row of the list. The row xml looks like this: <TextView android:id="@+id/text1" android:textSize="16sp" android:textStyle="bold" android:layout_width="fill_parent" android:layout_height="wrap_content"/> <TextView android:id="@+id/text2" android:textSize="14sp" android:layout_width="fill_parent" android:layout_height="wrap_content"/> so I was thinking using simplecursoradapter which supposedly makes my life easier by displaying the data in a list. However that is only true if I want to display the raw data. For the purpose of my program I need to do some computations on the raw data sets, then display them. I am not sure how to do that using SimpleCursorAdapter. Here's how I display the raw data: String[] from = new String[]{BtDbAdapter.KEY_EX_TYPE,BtDbAdapter.KEY_EX_TIMESTAMP}; int[] to = new int[]{R.id.text1, R.id.text2}; // Now create a simple cursor adapter and set it to display SimpleCursorAdapter records = new SimpleCursorAdapter(this, R.layout.exset_row, mExsetCursor, from, to); setListAdapter(records); Is there a way to do computation on the data in those rows before I bind it with the SimpleCursorAdapter? I was trying to use an alternative way of doing this by using arraylist and arrayadapter, but that way I dont know to how achieve displaying 2 items in a single row. This is my code for using arrayadapter which only display 1 text in a row instead of 2 textviews in a row: //fill in the array timestamp_arr = new ArrayList<String>(); type_arr = new ArrayList<String>(); fillRecord(); Log.d(TAG,"setting now in recordlist"); setListAdapter(new ArrayAdapter<String>(this, R.layout.list_item,timestamp_arr)); setListAdapter(new ArrayAdapter<String>(this, R.layout.list_item2,type_arr)); It's very obvious that it only displays one textview in a row because I set the second arrayadapter overwrites the first one! I was trying to use R.id.text1 and R.id.text2 for them, but it gave me some errors saying 04-23 01:40:58.658: ERROR/AndroidRuntime(3309): android.content.res.Resources$NotFoundException: Resource ID #0x7f070008 type #0x12 is not valid I believe the second method can achieve this, but I'm not sure how do deal with the layout problems, so if you any suggestions, please post them out. Thank you!!

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  • MySQL table organization and optimization (Rails)

    - by aguynamedloren
    I've been learning Ruby on Rails over the past few months with no prior programming experience. Lately, I've been thinking about database optimization and table organization. I know there are great books on the subject, but I typically learn by example / as I go. Here's a hypothetical situation: Let's say I am building a social network for a niche community with 250,000 members (users). The users have the ability to attend events. Let's say there are 50,000 past/present/future events. Much like Facebook events, a user can attend any number of events and an event can have any number of attendees. In the database, there would be a table for users and a table for events. Somehow I would have to create an association between the users and events. I could create an "events" column in the users table such that each user row would contain a hash of event IDs, or I could create an "attendees" column in the events table such that each event row would contain a hash of user IDs. Neither of these solutions seem ideal, however. On a users profile page, I want to display the list of events they are associated with, which would require scanning the 50,000 event rows for the user ID of said user if I include an "attendees" column in the events table. Likewise, on an event page, I want to display a list of attendees for the event, which would require scanning the 250,000 user rows for the event ID of said event if I include an "events" column in the users table. Option 3 would be to create a third table that contains the attendee information for each and every event - but I don't see how this would solve any problems. Are these non-issues? Rails makes accessing all of this information easy, but I guess I'm worried about scale. It is entirely possible that I am under-estimating the speed and processing power of modern databases / servers / etc. How long would it take to scan 250,000 user rows for specific event IDs - 10ms? 100ms? 1,000ms? I guess that's not that bad. Am I just over-thinking this?

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