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  • Simple Project Templates

    - by Geertjan
    The NetBeans sources include a module named "simple.project.templates": In the module sources, Tim Boudreau turns out to be the author of the code, so I asked him what it was all about, and if he could provide some usage code. His response, from approximately this time last year because it's been sitting in my inbox for a while, is below. Sure - though I think the javadoc in it is fairly complete.  I wrote it because I needed to create a bunch of project templates for Javacard, and all of the ways that is usually done were grotesque and complicated.  I figured we already have the ability to create files from templates, and we already have the ability to do substitutions in templates, so why not have a single file that defines the project as a list of file templates to create (with substitutions in the names) and some definitions of what should be in project properties. You can also add files to the project programmatically if you want.Basically, a template for an entire project is a .properties file.  Any line which doesn't have the prefix 'pp.' or 'pvp.' is treated as the definition of one file which should be created in the new project.  Any such line where the key ends in * means that file should be opened once the new project is created.  So, for example, in the nodejs module, the definition looks like: {{projectName}}.js*=Templates/javascript/HelloWorld.js .npmignore=node_hidden_templates/npmignore So, the first line means:  - Create a file with the same name as the project, using the HelloWorld template    - I.e. the left side of the line is the relative path of the file to create, and the right side is the path in the system filesystem for the template to use       - If the template is not one you normally want users to see, just register it in the system filesystem somewhere other than Templates/ (but remember to set the attribute that marks it as a template)  - Include that file in the set of files which should be opened in the editor once the new project is created. To actually create a project, first you just create a new ProjectCreator: ProjectCreator gen = new ProjectCreator( parentFolderOfNewProject ); Now, if you want to programmatically generate any files, in addition to those defined in the template, you can: gen.add (new FileCreator("nbproject", "project.xml", false) {     public DataObject create (FileObject project, Map<String,String> substitutions) throws IOException {          ...     } }); Then pass the FileObject for the project template (the properties file) to the ProjectCreator's createProject method (hmm, maybe it should be the string path to the project template instead, to save the caller trouble looking up the FileObject for the template).  That method looks like this: public final GeneratedProject createProject(final ProgressHandle handle, final String name, final FileObject template, final Map<String, String> substitutions) throws IOException { The name parameter should be the directory name for the new project;  the map is the strings you gathered in the wizard which should be used for substitutions.  createProject should be called on a background thread (i.e. use a ProgressInstantiatingIterator for the wizard iterator and just pass in the ProgressHandle you are given). The return value is a GeneratedProject object, which is just a holder for the created project directory and the set of DataObjects which should be opened when the wizard finishes. I'd love to see simple.project.templates moved out of the javacard cluster, as it is really useful and much simpler than any of the stuff currently done for generating projects.  It would also be possible to do much richer tools for creating projects in apisupport - i.e. choose (or create in the wizard) the templates you want to use, generate a skeleton wizard with a UI for all the properties you'd like to substitute, etc. Here is a partial project template from Javacard - for example usage, see org.netbeans.modules.javacard.wizard.ProjectWizardIterator in javacard.project (or the much simpler one in contrib/nodejs). #This properties file describes what to create when a project template is#instantiated.  The keys are paths on disk relative to the project root. #The values are paths to the templates to use for those files in the system#filesystem.  Any string inside {{ and }}'s will be substituted using properties#gathered in the template wizard.#Special key prefixes are #  pp. - indicates an entry for nbproject/project.properties#  pvp. - indicates an entry for nbproject/private/private.properties #File templates, in format [path-in-project=path-to-template]META-INF/javacard.xml=org-netbeans-modules-javacard/templates/javacard.xmlMETA-INF/MANIFEST.MF=org-netbeans-modules-javacard/templates/EAP_MANIFEST.MF APPLET-INF/applet.xml=org-netbeans-modules-javacard/templates/applet.xmlscripts/{{classnamelowercase}}.scr=org-netbeans-modules-javacard/templates/test.scrsrc/{{packagepath}}/{{classname}}.java*=Templates/javacard/ExtendedApplet.java nbproject/deployment.xml=org-netbeans-modules-javacard/templates/deployment.xml#project.properties contentspp.display.name={{projectname}}pp.platform.active={{activeplatform}} pp.active.device={{activedevice}}pp.includes=**pp.excludes= I will be using the above info in an upcoming blog entry and provide step by step instructions showing how to use them. However, anyone else out there should have enough info from the above to get started yourself!

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  • MySQL Connector/Net 6.6.3 Beta 2 has been released

    - by fernando
    MySQL Connector/Net 6.6.3, a new version of the all-managed .NET driver for MySQL has been released.  This is the second of two beta releases intended to introduce users to the new features in the release. This release is feature complete it should be stable enough for users to understand the new features and how we expect them to work.  As is the case with all non-GA releases, it should not be used in any production environment.  It is appropriate for use with MySQL server versions 5.0-5.6. It is now available in source and binary form from http://dev.mysql.com/downloads/connector/net/#downloads and mirror sites (note that not all mirror sites may be up to date at this point-if you can't find this version on some mirror, please try again later or choose another download site.) The 6.6 version of MySQL Connector/Net brings the following new features:   * Stored routine debugging   * Entity Framework 4.3 Code First support   * Pluggable authentication (now third parties can plug new authentications mechanisms into the driver).   * Full Visual Studio 2012 support: everything from Server Explorer to Intellisense&   the Stored Routine debugger. Stored Procedure Debugging ------------------------------------------- We are very excited to introduce stored procedure debugging into our Visual Studio integration.  It works in a very intuitive manner by simply clicking 'Debug Routine' from Server Explorer. You can debug stored routines, functions&   triggers. These release contains fixes specific of the debugger as well as other fixes specific of other areas of Connector/NET:   * Added feature to define initial values for InOut stored procedure arguments.   * Debugger: Fixed Visual Studio locked connection after debugging a routine.   * Fix for bug Cannot Create an Entity with a Key of Type String (MySQL bug #65289, Oracle bug #14540202).   * Fix for bug "CacheServerProperties can cause 'Packet too large' error". MySQL Bug #66578 Orabug #14593547.   * Fix for handling unnamed parameter in MySQLCommand. This fix allows the mysqlcommand to handle parameters without requiring naming (e.g. INSERT INTO Test (id,name) VALUES (?, ?) ) (MySQL Bug #66060, Oracle bug #14499549).   * Fixed end of line issue when debugging a routine.   * Added validation to avoid overwriting a routine backup file when it hasn't changed.   * Fixed inheritance on Entity Framework Code First scenarios. (MySql bug #63920 and Oracle bug #13582335).   * Fixed "Trying to customize column precision in Code First does not work" (MySql bug #65001, Oracle bug #14469048).   * Fixed bug ASP.NET Membership database fails on MySql database UTF32 (MySQL bug #65144, Oracle bug #14495292).   * Fix for MySqlCommand.LastInsertedId holding only 32 bit values (MySql bug #65452, Oracle bug #14171960).   * Fixed "Decimal type should have digits at right of decimal point", now default is 2, and user's changes in     EDM designer are recognized (MySql bug #65127, Oracle bug #14474342).   * Fix for NullReferenceException when saving an uninitialized row in Entity Framework (MySql bug #66066, Oracle bug #14479715).   * Fix for error when calling RoleProvider.RemoveUserFromRole(): causes an exception due to a wrong table being used (MySql bug #65805, Oracle bug #14405338).   * Fix for "Memory Leak on MySql.Data.MySqlClient.MySqlCommand", too many MemoryStream's instances created (MySql bug #65696, Oracle bug #14468204).   * Added ANTLR attribution notice (Oracle bug #14379162).   * Fix for debugger failing when having a routine with an if-elseif-else.   * Also the programming interface for authentication plugins has been redefined. Some limitations remains, due to the current debugger architecture:   * Some MySQL functions cannot be debugged currently (get_lock, release_lock, begin, commit, rollback, set transaction level)..   * Only one debug session may be active on a given server. The Debugger is feature complete at this point. We look forward to your feedback. Documentation ------------------------------------- You can view current Connector/Net documentation at http://dev.mysql.com/doc/refman/5.5/en/connector-net.html You can find our team blog at http://blogs.oracle.com/MySQLOnWindows. You can also post questions on our forums at http://forums.mysql.com/. Enjoy and thanks for the support!

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  • WIF, ADFS 2 and WCF&ndash;Part 5: Service Client (more Flexibility with WSTrustChannelFactory)

    - by Your DisplayName here!
    See the previous posts first. WIF includes an API to manually request tokens from a token service. This gives you more control over the request and more flexibility since you can use your own token caching scheme instead of being bound to the channel object lifetime. The API is straightforward. You first request a token from the STS and then use that token to create a channel to the relying party service. I’d recommend using the WS-Trust bindings that ship with WIF to talk to ADFS 2 – they are pre-configured to match the binding configuration of the ADFS 2 endpoints. The following code requests a token for a WCF service from ADFS 2: private static SecurityToken GetToken() {     // Windows authentication over transport security     var factory = new WSTrustChannelFactory(         new WindowsWSTrustBinding(SecurityMode.Transport),         stsEndpoint);     factory.TrustVersion = TrustVersion.WSTrust13;       var rst = new RequestSecurityToken     {         RequestType = RequestTypes.Issue,         AppliesTo = new EndpointAddress(svcEndpoint),         KeyType = KeyTypes.Symmetric     };       var channel = factory.CreateChannel();     return channel.Issue(rst); } Afterwards, the returned token can be used to create a channel to the service. Again WIF has some helper methods here that make this very easy: private static void CallService(SecurityToken token) {     // create binding and turn off sessions     var binding = new WS2007FederationHttpBinding(         WSFederationHttpSecurityMode.TransportWithMessageCredential);     binding.Security.Message.EstablishSecurityContext = false;       // create factory and enable WIF plumbing     var factory = new ChannelFactory<IService>(binding, new EndpointAddress(svcEndpoint));     factory.ConfigureChannelFactory<IService>();       // turn off CardSpace - we already have the token     factory.Credentials.SupportInteractive = false;       var channel = factory.CreateChannelWithIssuedToken<IService>(token);       channel.GetClaims().ForEach(c =>         Console.WriteLine("{0}\n {1}\n  {2} ({3})\n",             c.ClaimType,             c.Value,             c.Issuer,             c.OriginalIssuer)); } Why is this approach more flexible? Well – some don’t like the configuration voodoo. That’s a valid reason for using the manual approach. You also get more control over the token request itself since you have full control over the RST message that gets send to the STS. One common parameter that you may want to set yourself is the appliesTo value. When you use the automatic token support in the WCF federation binding, the appliesTo is always the physical service address. This means in turn that this address will be used as the audience URI value in the SAML token. Well – this in turn means that when you have an application that consists of multiple services, you always have to configure all physical endpoint URLs in ADFS 2 and in the WIF configuration of the service(s). Having control over the appliesTo allows you to use more symbolic realm names, e.g. the base address or a completely logical name. Since the URL is never de-referenced you have some degree of freedom here. In the next post we will look at the necessary code to request multiple tokens in a call chain. This is a common scenario when you first have to acquire a token from an identity provider and have to send that on to a federation gateway or Resource STS. Stay tuned.

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  • A deadlock was detected while trying to lock variables in SSIS

    Error: 0xC001405C at SQL Log Status: A deadlock was detected while trying to lock variables "User::RowCount" for read/write access. A lock cannot be acquired after 16 attempts. The locks timed out. Have you ever considered variable locking when building your SSIS packages? I expect many people haven’t just because most of the time you never see an error like the one above. I’ll try and explain a few key concepts about variable locking and hopefully you never will see that error. First of all, what is all this variable locking all about? Put simply SSIS variables have to be locked before they can be accessed, and then of course unlocked once you have finished with them. This is baked into SSIS, presumably to reduce the risk of race conditions, but with that comes some additional overhead in that you need to be careful to avoid lock conflicts in some scenarios. The most obvious place you will come across any hint of locking (no pun intended) is the Script Task or Script Component with their ReadOnlyVariables and ReadWriteVariables properties. These two properties allow you to enter lists of variables to be used within the task, or to put it another way, these lists of variables to be locked, so that they are available within the task. During the task pre-execute phase the variables and locked, you then use them during the execute phase when you code is run, and then unlocked for you during the post-execute phase. So by entering the variable names in one of the two list, the locking is taken care of for you, and you just read and write to the Dts.Variables collection that is exposed in the task for the purpose. As you can see in the image above, the variable PackageInt is specified, which means when I write the code inside that task I don’t have to worry about locking at all, as shown below. public void Main() { // Set the variable value to something new Dts.Variables["PackageInt"].Value = 199; // Raise an event so we can play in the event handler bool fireAgain = true; Dts.Events.FireInformation(0, "Script Task Code", "This is the script task raising an event.", null, 0, ref fireAgain); Dts.TaskResult = (int)ScriptResults.Success; } As you can see as well as accessing the variable, hassle free, I also raise an event. Now consider a scenario where I have an event hander as well as shown below. Now what if my event handler uses tries to use the same variable as well? Well obviously for the point of this post, it fails with the error quoted previously. The reason why is clearly illustrated if you consider the following sequence of events. Package execution starts Script Task in Control Flow starts Script Task in Control Flow locks the PackageInt variable as specified in the ReadWriteVariables property Script Task in Control Flow executes script, and the On Information event is raised The On Information event handler starts Script Task in On Information event handler starts Script Task in On Information event handler attempts to lock the PackageInt variable (for either read or write it doesn’t matter), but will fail because the variable is already locked. The problem is caused by the event handler task trying to use a variable that is already locked by the task in Control Flow. Events are always raised synchronously, therefore the task in Control Flow that is raising the event will not regain control until the event handler has completed, so we really do have un-resolvable locking conflict, better known as a deadlock. In this scenario we can easily resolve the problem by managing the variable locking explicitly in code, so no need to specify anything for the ReadOnlyVariables and ReadWriteVariables properties. public void Main() { // Set the variable value to something new, with explicit lock control Variables lockedVariables = null; Dts.VariableDispenser.LockOneForWrite("PackageInt", ref lockedVariables); lockedVariables["PackageInt"].Value = 199; lockedVariables.Unlock(); // Raise an event so we can play in the event handler bool fireAgain = true; Dts.Events.FireInformation(0, "Script Task Code", "This is the script task raising an event.", null, 0, ref fireAgain); Dts.TaskResult = (int)ScriptResults.Success; } Now the package will execute successfully because the variable lock has already been released by the time the event is raised, so no conflict occurs. For those of you with a SQL Engine background this should all sound strangely familiar, and boils down to getting in and out as fast as you can to reduce the risk of lock contention, be that SQL pages or SSIS variables. Unfortunately we cannot always manage the locking ourselves. The Execute SQL Task is very often used in conjunction with variables, either to pass in parameter values or get results out. Either way the task will manage the locking for you, and will fail when it cannot lock the variables it requires. The scenario outlined above is clear cut deadlock scenario, both parties are waiting on each other, so it is un-resolvable. The mechanism used within SSIS isn’t actually that clever, and whilst the message says it is a deadlock, it really just means it tried a few times, and then gave up. The last part of the error message is actually the most accurate in terms of the failure, A lock cannot be acquired after 16 attempts. The locks timed out.  Now this may come across as a recommendation to always manage locking manually in the Script Task or Script Component yourself, but I think that would be an overreaction. It is more of a reminder to be aware that in high concurrency scenarios, especially when sharing variables across multiple objects, locking is important design consideration. Update – Make sure you don’t try and use explicit locking as well as leaving the variable names in the ReadOnlyVariables and ReadWriteVariables lock lists otherwise you’ll get the deadlock error, you cannot lock a variable twice!

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  • Using Transaction Logging to Recover Post-Archived Essbase data

    - by Keith Rosenthal
    Data recovery is typically performed by restoring data from an archive.  Data added or removed since the last archive took place can also be recovered by enabling transaction logging in Essbase.  Transaction logging works by writing transactions to a log store.  The information in the log store can then be recovered by replaying the log store entries in sequence since the last archive took place.  The following information is recorded within a transaction log entry: Sequence ID Username Start Time End Time Request Type A request type can be one of the following categories: Calculations, including the default calculation as well as both server and client side calculations Data loads, including data imports as well as data loaded using a load rule Data clears as well as outline resets Locking and sending data from SmartView and the Spreadsheet Add-In.  Changes from Planning web forms are also tracked since a lock and send operation occurs during this process. You can use the Display Transactions command in the EAS console or the query database MAXL command to view the transaction log entries. Enabling Transaction Logging Transaction logging can be enabled at the Essbase server, application or database level by adding the TRANSACTIONLOGLOCATION essbase.cfg setting.  The following is the TRANSACTIONLOGLOCATION syntax: TRANSACTIONLOGLOCATION [appname [dbname]] LOGLOCATION NATIVE ENABLE | DISABLE Note that you can have multiple TRANSACTIONLOGLOCATION entries in the essbase.cfg file.  For example: TRANSACTIONLOGLOCATION Hyperion/trlog NATIVE ENABLE TRANSACTIONLOGLOCATION Sample Hyperion/trlog NATIVE DISABLE The first statement will enable transaction logging for all Essbase applications, and the second statement will disable transaction logging for the Sample application.  As a result, transaction logging will be enabled for all applications except the Sample application. A location on a physical disk other than the disk where ARBORPATH or the disk files reside is recommended to optimize overall Essbase performance. Configuring Transaction Log Replay Although transaction log entries are stored based on the LOGLOCATION parameter of the TRANSACTIONLOGLOCATION essbase.cfg setting, copies of data load and rules files are stored in the ARBORPATH/app/appname/dbname/Replay directory to optimize the performance of replaying logged transactions.  The default is to archive client data loads, but this configuration setting can be used to archive server data loads (including SQL server data loads) or both client and server data loads. To change the type of data to be archived, add the TRANSACTIONLOGDATALOADARCHIVE configuration setting to the essbase.cfg file.  Note that you can have multiple TRANSACTIONLOGDATALOADARCHIVE entries in the essbase.cfg file to adjust settings for individual applications and databases. Replaying the Transaction Log and Transaction Log Security Considerations To replay the transactions, use either the Replay Transactions command in the EAS console or the alter database MAXL command using the replay transactions grammar.  Transactions can be replayed either after a specified log time or using a range of transaction sequence IDs. The default when replaying transactions is to use the security settings of the user who originally performed the transaction.  However, if that user no longer exists or that user's username was changed, the replay operation will fail. Instead of using the default security setting, add the REPLAYSECURITYOPTION essbase.cfg setting to use the security settings of the administrator who performs the replay operation.  REPLAYSECURITYOPTION 2 will explicitly use the security settings of the administrator performing the replay operation.  REPLAYSECURITYOPTION 3 will use the administrator security settings if the original user’s security settings cannot be used. Removing Transaction Logs and Archived Replay Data Load and Rules Files Transaction logs and archived replay data load and rules files are not automatically removed and are only removed manually.  Since these files can consume a considerable amount of space, the files should be removed on a periodic basis. The transaction logs should be removed one database at a time instead of all databases simultaneously.  The data load and rules files associated with the replayed transactions should be removed in chronological order from earliest to latest.  In addition, do not remove any data load and rules files with a timestamp later than the timestamp of the most recent archive file. Partitioned Database Considerations For partitioned databases, partition commands such as synchronization commands cannot be replayed.  When recovering data, the partition changes must be replayed manually and logged transactions must be replayed in the correct chronological order. If the partitioned database includes any @XREF commands in the calc script, the logged transactions must be selectively replayed in the correct chronological order between the source and target databases. References For additional information, please see the Oracle EPM System Backup and Recovery Guide.  For EPM 11.1.2.2, the link is http://docs.oracle.com/cd/E17236_01/epm.1112/epm_backup_recovery_1112200.pdf

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  • Updating a database connection password using a script

    - by Tim Dexter
    An interesting customer requirement that I thought was worthy of sharing today. Thanks to James for the requirement and Bryan for the proposed solution and me for testing the solution and proving it works :0) A customers implementation of Sarbanes Oxley requires them to change all database account passwords every 90 days. This is scripted leveraging shell scripts today for most of their environments. But how can they manage the BI Publisher connections? Now, the customer is running 11g and therefore using weblogic on the middle tier, which is the first clue to Bryans proposed solution. To paraphrase and embellish Bryan's solution a little; why not use a JNDI connection from BIP to the database. Then employ the web logic scripting engine to make updates to the JNDI as needed? BIP is completely uninvolved and with a little 'timing' users will be completely unaware of the password updates i.e. change the password when reports are not being executed. Perfect! James immediately tracked down the WLST script that could be used here, http://middlewaremagic.com/weblogic/?p=4261 (thanks Ravish) Now it was just a case of testing the theory. Some steps: Create the JNDI connection in WLS Create the JNDI connection in BI Publisher pointing to the WLS connection Build new data models using or re-point data sources to use the JNDI connection. Create the WLST script to update the WLS JNDI password as needed. Test! Some details. Creating the JNDI connection in web logic is pretty straightforward. Log into hte console and look for Data Sources under the Services section of the home page and click it Click New >> Generic Datasource Give the connection a name. For the JNDI name, prefix it with 'jdbc/' so I have 'jdbc/localdb' - this name is important you'll need it on the BIP side. Select your db type - this will influence the drivers and information needed on the next page. Being a company man, Im using an Oracle db. Click Next Select the driver of choice, theres lots I know, you can read about them I just chose 'Oracle's Driver (Thin) for Instance connections; Versions 9.0.1 and later' Click Next >> Next Fill out the db name (SID), server, port, username to connect and password >> Next Test the config to ensure you can connect. >> Next Now you need to deploy the connection to your BI server, select it and click Next. You're done with the JNDI config. Creating the JNDI connection on the Publisher side is covered here. Just remember to the connection name you created in WLS e.g. 'jdbc/localdb' Not gonna tell you how to do this, go read the user guide :0) Suffice to say, it works. This requires a little reading around the subject to understand the scripting engine and how to execute scripts. Nicely covered here. However a bit of googlin' and I found an even easier way of running the script. ${ServerHome}/common/bin/wlst.sh updatepwd.py Where updatepwd.py is my script file, it can be in another directory. As part of the wlst.sh script your environment is set up for you so its very simple to execute. The nitty gritty: Need to take Ravish's script above and create a file with a .py extension. Its going to need some modification, as he explains on the web page, to make it work in your environment. I played around with it for a while but kept running into errors. The script as is, tries to loop through all of your connections and modify the user and passwords for each. Not quite what we are looking for. Remember our requirement is to just update the password for a given connection. I also found another issue with the script. WLS 10.x does not allow updates to passwords using clear type ie un-encrypted text while the server is in production mode. Its a bit much to set it back to developer mode bounce it, change the passwords and then bounce and then change back to production and bounce again. After lots of messing about I finally came up with the following: ############################################################################# # # Update password for JNDI connections # ############################################################################# print("*** Trying to Connect.... *****") connect('weblogic','welcome1','t3://localhost:7001') print("*** Connected *****") edit() startEdit() print ("*** Encrypt the password ***") en = encrypt('hr') print "Encrypted pwd: ", en print ("*** Changing pwd for LocalDB ***") dsName = 'LocalDB' print 'Changing Password for DataSource ', dsName cd('/JDBCSystemResources/'+dsName+'/JDBCResource/'+dsName+'/JDBCDriverParams/'+dsName) set('PasswordEncrypted',en) save() activate() Its pretty simple and you can expand on it to loop through the data sources and change each as needed. I have hardcoded the password into the file but you can pass it as a parameter as needed using the properties file method. Im not going to get into the detail of that here but its covered with an example here. Couple of points to note: 1. The change to the password requires a server bounce to get the changes picked up. You can add that to the shell script you will use to call the script above. 2. The script above needs to be run from the MW_HOME\user_projects\domains\bifoundation_domain directory to get the encryption libraries set correctly. My command to run the whole script was: d:\oracle\bi_mw\wlserver_10.3\common\bin\wlst.cmd updatepwd.py - where wlst.cmd is the scripting command line and updatepwd.py was my update password script above. I have not quite spoon fed everything you need to make it a robust script but at least you know you can do it and you can work out the rest I think :0)

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  • WebSocket API 1.1 released!

    - by Pavel Bucek
    Its my please to announce that JSR 356 – Java API for WebSocket maintenance release ballot vote finished with majority of “yes” votes (actually, only one eligible voter did not vote, all other votes were “yeses”). New release is maintenance release and it addresses only one issue:  WEBSOCKET_SPEC-226. What changed in the 1.1? Version 1.1 is fully backwards compatible with version 1.0, there are only two methods added to javax.websocket.Session: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 /** * Register to handle to incoming messages in this conversation. A maximum of one message handler per * native websocket message type (text, binary, pong) may be added to each Session. I.e. a maximum * of one message handler to handle incoming text messages a maximum of one message handler for * handling incoming binary messages, and a maximum of one for handling incoming pong * messages. For further details of which message handlers handle which of the native websocket * message types please see {@link MessageHandler.Whole} and {@link MessageHandler.Partial}. * Adding more than one of any one type will result in a runtime exception. * * @param clazz   type of the message processed by message handler to be registered. * @param handler whole message handler to be added. * @throws IllegalStateException if there is already a MessageHandler registered for the same native *                               websocket message type as this handler. */ public void addMessageHandler(Class<T> clazz, MessageHandler.Whole<T> handler); /** * Register to handle to incoming messages in this conversation. A maximum of one message handler per * native websocket message type (text, binary, pong) may be added to each Session. I.e. a maximum * of one message handler to handle incoming text messages a maximum of one message handler for * handling incoming binary messages, and a maximum of one for handling incoming pong * messages. For further details of which message handlers handle which of the native websocket * message types please see {@link MessageHandler.Whole} and {@link MessageHandler.Partial}. * Adding more than one of any one type will result in a runtime exception. * * * @param clazz   type of the message processed by message handler to be registered. * @param handler partial message handler to be added. * @throws IllegalStateException if there is already a MessageHandler registered for the same native *                               websocket message type as this handler. */ public void addMessageHandler(Class<T> clazz, MessageHandler.Partial<T> handler); Why do we need to add those methods? Short and not precise version: to support Lambda expressions as MessageHandlers. Longer and slightly more precise explanation: old Session#addMessageHandler method (which is still there and works as it worked till now) does rely on getting the generic parameter during the runtime, which is not (always) possible. The unfortunate part is that it works for some common cases and the expert group did not catch this issue before 1.0 release because of that. The issue is really clearly visible when Lambdas are used as message handlers: 1 2 3 session.addMessageHandler(message -> { System.out.println("### Received: " + message); }); There is no way for the JSR 356 implementation to get the type of the used Lambda expression, thus this call will always result in an exception. Since all modern IDEs do recommend to use Lambda expressions when possible and MessageHandler interfaces are single method interfaces, it basically just scream “use Lambdas” all over the place but when you do that, the application will fail during runtime. Only solution we currently have is to explicitly provide the type of registered MessageHandler. (There might be another sometime in the future when generic type reification is introduced, but that is not going to happen soon enough). So the example above will then be: 1 2 3 session.addMessageHandler(String.class, message -> { System.out.println("### Received: " + message); }); and voila, it works. There are some limitations – you cannot do 1 List<String>.class , so you will need to encapsulate these types when you want to use them in MessageHandler implementation (something like “class MyType extends ArrayList<String>”). There is no better way how to solve this issue, because Java currently does not provide good way how to describe generic types. The api itself is available on maven central, look for javax.websocket:javax.websocket-api:1.1. The reference implementation is project Tyrus, which implements WebSocket API 1.1 from version 1.8.

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  • Windows in StreamInsight: Hopping vs. Snapshot

    - by Roman Schindlauer
    Three weeks ago, we explained the basic concept of windows in StreamInsight: defining sets of events that serve as arguments for set-based operations, like aggregations. Today, we want to discuss the so-called Hopping Windows and compare them with Snapshot Windows. We will compare these two, because they can serve similar purposes with different behaviors; we will discuss the remaining window type, Count Windows, another time. Hopping (and its syntactic-sugar-sister Tumbling) windows are probably the most straightforward windowing concept in StreamInsight. A hopping window is defined by its length, and the offset from one window to the next. They are aligned with some absolute point on the timeline (which can also be given as a parameter to the window) and create sets of events. The diagram below shows an example of a hopping window with length of 1h and hop size (the offset) of 15 minutes, hence creating overlapping windows:   Two aspects in this diagram are important: Since this window is overlapping, an event can fall into more than one windows. If an (interval) event spans a window boundary, its lifetime will be clipped to the window, before it is passed to the set-based operation. That’s the default and currently only available window input policy. (This should only concern you if you are using a time-sensitive user-defined aggregate or operator.) The set-based operation will be applied to each of these sets, yielding a result. This result is: A single scalar value in case of built-in or user-defined aggregates. A subset of the input payloads, in case of the TopK operator. Arbitrary events, when using a user-defined operator. The timestamps of the result are almost always the ones of the windows. Only the user-defined  operator can create new events with timestamps. (However, even these event lifetimes are subject to the window’s output policy, which is currently always to clip to the window end.) Let’s assume we were calculating the sum over some payload field: var result = from window in source.HoppingWindow( TimeSpan.FromHours(1), TimeSpan.FromMinutes(15), HoppingWindowOutputPolicy.ClipToWindowEnd) select new { avg = window.Avg(e => e.Value) }; Now each window is reflected by one result event:   As you can see, the window definition defines the output frequency. No matter how many or few events we got from the input, this hopping window will produce one result every 15 minutes – except for those windows that do not contain any events at all, because StreamInsight window operations are empty-preserving (more about that another time). The “forced” output for every window can become a performance issue if you have a real-time query with many events in a wide group & apply – let me explain: imagine you have a lot of events that you group by and then aggregate within each group – classical streaming pattern. The hopping window produces a result in each group at exactly the same point in time for all groups, since the window boundaries are aligned with the timeline, not with the event timestamps. This means that the query output will become very bursty, delivering the results of all the groups at the same point in time. This becomes especially obvious if the events are long-lasting, spanning multiple windows each, so that the produced result events do not change their value very often. In such a case, a snapshot window can remedy. Snapshot windows are more difficult to explain than hopping windows: they represent those periods in time, when no event changes occur. In other words, if you mark all event start and and times on your timeline, then you are looking at all snapshot window boundaries:   If your events are never overlapping, the snapshot window will not make much sense. It is commonly used together with timestamp modification, which make it a very powerful tool. Or as Allan Mitchell expressed in in a recent tweet: “I used to look at SnapshotWindow() with disdain. Now she is my mistress, the one I turn to in times of trouble and need”. Let’s look at a simple example: I want to compute the average of some value in my events over the last minute. I don’t want this output be produced at fixed intervals, but at soon as it changes (that’s the true event-driven spirit!). The snapshot window will include all currently active event at each point in time, hence we need to extend our original events’ lifetimes into the future: Applying the Snapshot window on these events, it will appear to be “looking back into the past”: If you look at the result produced in this diagram, you can easily prove that, at each point in time, the current event value represents the average of all original input event within the last minute. Here is the LINQ representation of that query, applying the lifetime extension before the snapshot window: var result = from window in source .AlterEventDuration(e => TimeSpan.FromMinutes(1)) .SnapshotWindow(SnapshotWindowOutputPolicy.Clip) select new { avg = window.Avg(e => e.Value) }; With more complex modifications of the event lifetimes you can achieve many more query patterns. For instance “running totals” by keeping the event start times, but snapping their end times to some fixed time, like the end of the day. Each snapshot then “sees” all events that have happened in the respective time period so far. Regards, The StreamInsight Team

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  • Defaulting the HLSL Vertex and Pixel Shader Levels to Feature Level 9_1 in VS 2012

    - by Michael B. McLaughlin
    I love Visual Studio 2012. But this is not a post about that. This is a post about tweaking one particular parameter that I’ve found a bit annoying. Disclaimer: You will be modifying important MSBuild files. If you screw up you will break your build tools. And maybe your computer will catch fire. I’m not responsible. No warranties or guaranties of any sort. This info is provided “as is”. By default, if you add a new vertex shader or pixel shader item to a project, it will be set to build with shader profile 4.0_level_9_3. If you need 9_3 functionality, this is all well and good. But (especially for Windows Store apps) you really want to target the lowest shader profile possible so that your game will run on as many computers as possible. So it’s a good idea to default to 9_1. To do this you could add in new HLSL files via “Add->New Item->Visual C++->HLSL->______ Shader File (.hlsl)” and then edit the shader files’ properties to set them manually to use 9_1 via “Properties->HLSL Compiler->General->Shader Model”. This is fine unless you forget to do this once and then submit your game with 9_3 shaders instead of 9_1 shaders to the Windows Store or to some other game store. Then you’d wind up with either rejection or angry “this doesn’t work on my computer! ripoff!” messages. There’s another option though. In “Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\ItemTemplates\VC\HLSL\1033\VertexShader” (note the path might vary slightly for you if you are using a 32-bit system or have a non-ENU version of Visual Studio 2012) you will find a “VertexShader.vstemplate” file. If you open this file in a text editor (e.g. Notepad++), then inside the CustomParameters tag within the TemplateContent tag you should see a CustomParameter tag for the ShaderType, i.e.: <CustomParameter Name="$ShaderType$" Value="Vertex"/> On a new line, we are going to add another CustomParameter tag to the CustomParameters tag. It will look like this: <CustomParameter Name="$ShaderModel$" Value="4.0_level_9_1"/> such that we now have:     <CustomParameters>       <CustomParameter Name="$ShaderType$" Value="Vertex"/>       <CustomParameter Name="$ShaderModel$" Value="4.0_level_9_1"/>     </CustomParameters> You can then save the file (you will need to be an Administrator or have Administrator access). Back in the 1033 directory (or whatever the number is for your language), go into the “PixelShader” directory. Edit the “PixelShader.vstemplate” file and make the same change (note that this time $ShaderType$ is “Pixel” not “Vertex”; you shouldn’t be changing that line anyway, but if you were to just copy and replace the above four lines then you will wind up creating pixel shaders that the HLSL compiler would try to compile as vertex shaders, with all sort of weird errors as a result). Once you’ve added the $ShaderModel$ line to “PixelShader.vstemplate” and have saved it, everything should be done. Since Feature Level 9_1 and 9_3 don’t support any of the other shader types, those are set to default to their appropriate minimums already (Compute and Geometry are set to “4.0” and Domain and Hull are set to “5.0”, which are their respective minimums (though not all 4.0 cards support Compute shaders; they were an optional feature added with DirectX 10.1 and only became required for DirectX 11 hardware). In case you are wondering where these magic values come from, you can find them all in the “fxc.xml” file in the “\Program Files (x86)\MSBuild\Microsoft.CPP\v4.0\V110\1033” directory (or whatever your language number is; 1033 is ENU and various other product languages have their own respective numbers (see: http://msdn.microsoft.com/en-us/goglobal/bb964664.aspx ) such that Japanese is 1041 (for example), though for all I know MSBuild tasks might be 1033 for everyone). If, like me, you installed VS 2012 to a drive other than the C:\ drive, you will find the vstemplate files in the drive to which you installed VS 2012 (D:\ in my case) but you will find the fxc.xml file on the C:\ drive. You should not edit fxc.xml. You will almost definitely break things by doing that; it’s just something you can look through to see all the other options that the FXC task takes such that you could, if needed, add further CustomParameter tags if you wanted to default to other supported options. I haven’t tried any others though so I don’t have any advice on how to set them.

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  • MVVM - how to make creating viewmodels at runtime less painfull

    - by Mr Happy
    I apologize for the long question, it reads a bit as a rant, but I promise it's not! I've summarized my question(s) below In the MVC world, things are straightforward. The Model has state, the View shows the Model, and the Controller does stuff to/with the Model (basically), a controller has no state. To do stuff the Controller has some dependencies on web services, repository, the lot. When you instantiate a controller you care about supplying those dependencies, nothing else. When you execute an action (method on Controller), you use those dependencies to retrieve or update the Model or calling some other domain service. If there's any context, say like some user wants to see the details of a particular item, you pass the Id of that item as parameter to the Action. Nowhere in the Controller is there any reference to any state. So far so good. Enter MVVM. I love WPF, I love data binding. I love frameworks that make data binding to ViewModels even easier (using Caliburn Micro a.t.m.). I feel things are less straightforward in this world though. Let's do the exercise again: the Model has state, the View shows the ViewModel, and the ViewModel does stuff to/with the Model (basically), a ViewModel does have state! (to clarify; maybe it delegates all the properties to one or more Models, but that means it must have a reference to the model one way or another, which is state in itself) To do stuff the ViewModel has some dependencies on web services, repository, the lot. When you instantiate a ViewModel you care about supplying those dependencies, but also the state. And this, ladies and gentlemen, annoys me to no end. Whenever you need to instantiate a ProductDetailsViewModel from the ProductSearchViewModel (from which you called the ProductSearchWebService which in turn returned IEnumerable<ProductDTO>, everybody still with me?), you can do one of these things: call new ProductDetailsViewModel(productDTO, _shoppingCartWebService /* dependcy */);, this is bad, imagine 3 more dependencies, this means the ProductSearchViewModel needs to take on those dependencies as well. Also changing the constructor is painfull. call _myInjectedProductDetailsViewModelFactory.Create().Initialize(productDTO);, the factory is just a Func, they are easily generated by most IoC frameworks. I think this is bad because Init methods are a leaky abstraction. You also can't use the readonly keyword for fields that are set in the Init method. I'm sure there are a few more reasons. call _myInjectedProductDetailsViewModelAbstractFactory.Create(productDTO); So... this is the pattern (abstract factory) that is usually recommended for this type of problem. I though it was genious since it satisfies my craving for static typing, until I actually started using it. The amount of boilerplate code is I think too much (you know, apart from the ridiculous variable names I get use). For each ViewModel that needs runtime parameters you'll get two extra files (factory interface and implementation), and you need to type the non-runtime dependencies like 4 extra times. And each time the dependencies change, you get to change it in the factory as well. It feels like I don't even use an DI container anymore. (I think Castle Windsor has some kind of solution for this [with it's own drawbacks, correct me if I'm wrong]). do something with anonymous types or dictionary. I like my static typing. So, yeah. Mixing state and behavior in this way creates a problem which don't exist at all in MVC. And I feel like there currently isn't a really adequate solution for this problem. Now I'd like to observe some things: People actually use MVVM. So they either don't care about all of the above, or they have some brilliant other solution. I haven't found an indepth example of MVVM with WPF. For example, the NDDD-sample project immensely helped me understand some DDD concepts. I'd really like it if someone could point me in the direction of something similar for MVVM/WPF. Maybe I'm doing MVVM all wrong and I should turn my design upside down. Maybe I shouldn't have this problem at all. Well I know other people have asked the same question so I think I'm not the only one. To summarize Am I correct to conclude that having the ViewModel being an integration point for both state and behavior is the reason for some difficulties with the MVVM pattern as a whole? Is using the abstract factory pattern the only/best way to instantiate a ViewModel in a statically typed way? Is there something like an in depth reference implementation available? Is having a lot of ViewModels with both state/behavior a design smell?

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  • How to handle updated configuration when it's already been cloned for editing

    - by alexrussell
    Really sorry about the title that probably doesn't make much sense. Hopefully I can explain myself better here as it's something that's kinda bugged me for ages, and is now becoming a pressing concern as I write a bit of software with configuration. Most software comes with default configuration options stored in the app itself, and then there's a configuration file (let's say) that a user can edit. Once created/edited for the first time, subsequent updates to the application can not (easily) modify this configuration file for fear of clobbering the user's own changes to the default configuration. So my question is, if my application adds a new configurable parameter, what's the best way to aid discoverability of the setting and allow the user (developer) to override it as nicely as possible given the following constraints: I actually don't have a canonical default config in the application per se, it's more of a 'cascading filesystem'-like affair - the config template is stored in default/config.json and when the user wishes to edit the configuration, it's copied to user/config.json. If a user config is found it is used - there is no automatic overriding of a subset of keys, the whole new file is used and that's that. If there's no user config the default config is used. When a user wishes to edit the config they run a command to 'generate' it for them (which simply copies the config.json file from the default to the user directory). There is no UI for the configuration options as it's not appropriate to the userbase (think of my software as a library or something, the users are developers, the config is done in the user/config.json file). Due to my software being library-like there's no simple way to, on updating of the software, run some tasks automatically (so any ideas of look at the current config, compare to template config, add ing missing keys) aren't appropriate. The only solution I can think of right now is to say "there's a new config setting X" in release notes, but this doesn't seem ideal to me. If you want any more information let me know. The above specifics are not actually 100% true to my situation, but they represent the problem equally well with lower complexity. If you do want specifics, however, I can explain the exact setup. Further clarification of the type of configuration I mean: think of the Atom code editor. There appears to be a default 'template' config file somewhere, but as soon as a configuration option is edited ~/.atom/config.cson is generated and the setting goes in there. From now on is Atom is updated and gets a new configuration key, this file cannot be overwritten by Atom without a lot of effort to ensure that the addition/modification of the key does not clobber. In Atom's case, because there is a GUI for editing settings, they can get away with just adding the UI for the new setting into the UI to aid 'discoverability' of the new setting. I don't have that luxury. Clarification of my constraints and what I'm actually looking for: The software I'm writing is actually a package for a larger system. This larger system is what provides the configuration, and the way it works is kinda fixed - I just do a config('some.key') kinda call and it knows to look to see if the user has a config clone and if so use it, otherwise use the default config which is part of my package. Now, while I could make my application edit the user's configuration files (there is a convention about where they're stored), it's generally not done, so I'd like to live with the constraints of the system I'm using if possible. And it's not just about discoverability either, one large concern is that the addition of a configuration key won't actually work as soon as the user has their own copy of the original template. Adding the key to the template won't make a difference as that file is never read. As such, I think this is actually quite a big flaw in the design of the configuration cascading system and thus needs to be taken up with my upstream. So, thinking about it, based on my constraints, I don't think there's going to be a good solution save for either editing the user's configuration or using a new config file every time there are updates to the default configuration. Even the release notes idea from above isn't doable as, if the user does not follow the advice, suddenly I have a config key with no value (user-defined or default). So the new question is this: what is the general way to solve the problem of having a default configuration in template config files and allowing a user to make user-specific version of these in order to override the defaults? A per-key cascade (rather than per-file cascade) where the user only specifies their overrides? In this case, what happens if a configuration value is an array - do we replace or append to the default (or, more realistically, how does the user specify whether they wish to replace or append to)? It seems like configuration is kinda hard, so how is it solved in the wild?

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  • concurrency::index<N> from amp.h

    - by Daniel Moth
    Overview C++ AMP introduces a new template class index<N>, where N can be any value greater than zero, that represents a unique point in N-dimensional space, e.g. if N=2 then an index<2> object represents a point in 2-dimensional space. This class is essentially a coordinate vector of N integers representing a position in space relative to the origin of that space. It is ordered from most-significant to least-significant (so, if the 2-dimensional space is rows and columns, the first component represents the rows). The underlying type is a signed 32-bit integer, and component values can be negative. The rank field returns N. Creating an index The default parameterless constructor returns an index with each dimension set to zero, e.g. index<3> idx; //represents point (0,0,0) An index can also be created from another index through the copy constructor or assignment, e.g. index<3> idx2(idx); //or index<3> idx2 = idx; To create an index representing something other than 0, you call its constructor as per the following 4-dimensional example: int temp[4] = {2,4,-2,0}; index<4> idx(temp); Note that there are convenience constructors (that don’t require an array argument) for creating index objects of rank 1, 2, and 3, since those are the most common dimensions used, e.g. index<1> idx(3); index<2> idx(3, 6); index<3> idx(3, 6, 12); Accessing the component values You can access each component using the familiar subscript operator, e.g. One-dimensional example: index<1> idx(4); int i = idx[0]; // i=4 Two-dimensional example: index<2> idx(4,5); int i = idx[0]; // i=4 int j = idx[1]; // j=5 Three-dimensional example: index<3> idx(4,5,6); int i = idx[0]; // i=4 int j = idx[1]; // j=5 int k = idx[2]; // k=6 Basic operations Once you have your multi-dimensional point represented in the index, you can now treat it as a single entity, including performing common operations between it and an integer (through operator overloading): -- (pre- and post- decrement), ++ (pre- and post- increment), %=, *=, /=, +=, -=,%, *, /, +, -. There are also operator overloads for operations between index objects, i.e. ==, !=, +=, -=, +, –. Here is an example (where no assertions are broken): index<2> idx_a; index<2> idx_b(0, 0); index<2> idx_c(6, 9); _ASSERT(idx_a.rank == 2); _ASSERT(idx_a == idx_b); _ASSERT(idx_a != idx_c); idx_a += 5; idx_a[1] += 3; idx_a++; _ASSERT(idx_a != idx_b); _ASSERT(idx_a == idx_c); idx_b = idx_b + 10; idx_b -= index<2>(4, 1); _ASSERT(idx_a == idx_b); Usage You'll most commonly use index<N> objects to index into data types that we'll cover in future posts (namely array and array_view). Also when we look at the new parallel_for_each function we'll see that an index<N> object is the single parameter to the lambda, representing the (multi-dimensional) thread index… In the next post we'll go beyond being able to represent an N-dimensional point in space, and we'll see how to define the N-dimensional space itself through the extent<N> class. Comments about this post by Daniel Moth welcome at the original blog.

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  • Migrating Core Data to new UIManagedDocument in iOS 5

    - by samerpaul
    I have an app that has been on the store since iOS 3.1, so there is a large install base out there that still uses Core Data loaded up in my AppDelegate. In the most recent set of updates, I raised the minimum version to 4.3 but still kept the same way of loading the data. Recently, I decided it's time to make the minimum version 5.1 (especially with 6 around the corner), so I wanted to start using the new fancy UIManagedDocument way of using Core Data. The issue with this though is that the old database file is still sitting in the iOS app, so there is no migrating to the new document. You have to basically subclass UIManagedDocument with a new model class, and override a couple of methods to do it for you. Here's a tutorial on what I did for my app TimeTag.  Step One: Add a new class file in Xcode and subclass "UIManagedDocument" Go ahead and also add a method to get the managedObjectModel out of this class. It should look like:   @interface TimeTagModel : UIManagedDocument   - (NSManagedObjectModel *)managedObjectModel;   @end   Step two: Writing the methods in the implementation file (.m) I first added a shortcut method for the applicationsDocumentDirectory, which returns the URL of the app directory.  - (NSURL *)applicationDocumentsDirectory {     return [[[NSFileManagerdefaultManager] URLsForDirectory:NSDocumentDirectoryinDomains:NSUserDomainMask] lastObject]; }   The next step was to pull the managedObjectModel file itself (.momd file). In my project, it's called "minimalTime". - (NSManagedObjectModel *)managedObjectModel {     NSString *path = [[NSBundlemainBundle] pathForResource:@"minimalTime"ofType:@"momd"];     NSURL *momURL = [NSURL fileURLWithPath:path];     NSManagedObjectModel *managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:momURL];          return managedObjectModel; }   After that, I need to check for a legacy installation and migrate it to the new UIManagedDocument file instead. This is the overridden method: - (BOOL)configurePersistentStoreCoordinatorForURL:(NSURL *)storeURL ofType:(NSString *)fileType modelConfiguration:(NSString *)configuration storeOptions:(NSDictionary *)storeOptions error:(NSError **)error {     // If legacy store exists, copy it to the new location     NSURL *legacyPersistentStoreURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"minimalTime.sqlite"];          NSFileManager* fileManager = [NSFileManagerdefaultManager];     if ([fileManager fileExistsAtPath:legacyPersistentStoreURL.path])     {         NSLog(@"Old db exists");         NSError* thisError = nil;         [fileManager replaceItemAtURL:storeURL withItemAtURL:legacyPersistentStoreURL backupItemName:niloptions:NSFileManagerItemReplacementUsingNewMetadataOnlyresultingItemURL:nilerror:&thisError];     }          return [superconfigurePersistentStoreCoordinatorForURL:storeURL ofType:fileType modelConfiguration:configuration storeOptions:storeOptions error:error]; }   Basically what's happening above is that it checks for the minimalTime.sqlite file inside the app's bundle on the iOS device.  If the file exists, it tells you inside the console, and then tells the fileManager to replace the storeURL (inside the method parameter) with the legacy URL. This basically gives your app access to all the existing data the user has generated (otherwise they would load into a blank app, which would be disastrous). It returns a YES if successful (by calling it's [super] method). Final step: Actually load this database Due to how my app works, I actually have to load the database at launch (instead of shortly after, which would be ideal). I call a method called loadDatabase, which looks like this: -(void)loadDatabase {     static dispatch_once_t onceToken;          // Only do this once!     dispatch_once(&onceToken, ^{         // Get the URL         // The minimalTimeDB name is just something I call it         NSURL *url = [[selfapplicationDocumentsDirectory] URLByAppendingPathComponent:@"minimalTimeDB"];         // Init the TimeTagModel (our custom class we wrote above) with the URL         self.timeTagDB = [[TimeTagModel alloc] initWithFileURL:url];           // Setup the undo manager if it's nil         if (self.timeTagDB.undoManager == nil){             NSUndoManager *undoManager = [[NSUndoManager  alloc] init];             [self.timeTagDB setUndoManager:undoManager];         }                  // You have to actually check to see if it exists already (for some reason you can't just call "open it, and if it's not there, create it")         if ([[NSFileManagerdefaultManager] fileExistsAtPath:[url path]]) {             // If it does exist, try to open it, and if it doesn't open, let the user (or at least you) know!             [self.timeTagDB openWithCompletionHandler:^(BOOL success){                 if (!success) {                     // Handle the error.                     NSLog(@"Error opening up the database");                 }                 else{                     NSLog(@"Opened the file--it already existed");                     [self refreshData];                 }             }];         }         else {             // If it doesn't exist, you need to attempt to create it             [self.timeTagDBsaveToURL:url forSaveOperation:UIDocumentSaveForCreatingcompletionHandler:^(BOOL success){                 if (!success) {                     // Handle the error.                     NSLog(@"Error opening up the database");                 }                 else{                     NSLog(@"Created the file--it did not exist");                     [self refreshData];                 }             }];         }     }); }   If you're curious what refreshData looks like, it sends out a NSNotification that the database has been loaded: -(void)refreshData {     NSNotification* refreshNotification = [NSNotificationnotificationWithName:kNotificationCenterRefreshAllDatabaseData object:self.timeTagDB.managedObjectContext  userInfo:nil];     [[NSNotificationCenter defaultCenter] postNotification:refreshNotification];     }   The kNotificationCenterRefreshAllDatabaseData is just a constant I have defined elsewhere that keeps track of all the NSNotification names I use. I pass the managedObjectContext of the newly created file so that my view controllers can have access to it, and start passing it around to one another. The reason we do this as a Notification is because this is being run in the background, so we can't know exactly when it finishes. Make sure you design your app for this! Have some kind of loading indicator, or make sure your user can't attempt to create a record before the database actually exists, because it will crash the app.

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  • A Basic Thread

    - by Joe Mayo
    Most of the programs written are single-threaded, meaning that they run on the main execution thread. For various reasons such as performance, scalability, and/or responsiveness additional threads can be useful. .NET has extensive threading support, from the basic threads introduced in v1.0 to the Task Parallel Library (TPL) introduced in v4.0. To get started with threads, it's helpful to begin with the basics; starting a Thread. Why Do I Care? The scenario I'll use for needing to use a thread is writing to a file.  Sometimes, writing to a file takes a while and you don't want your user interface to lock up until the file write is done. In other words, you want the application to be responsive to the user. How Would I Go About It? The solution is to launch a new thread that performs the file write, allowing the main thread to return to the user right away.  Whenever the file writing thread completes, it will let the user know.  In the meantime, the user is free to interact with the program for other tasks. The following examples demonstrate how to do this. Show Me the Code? The code we'll use to work with threads is in the System.Threading namespace, so you'll need the following using directive at the top of the file: using System.Threading; When you run code on a thread, the code is specified via a method.  Here's the code that will execute on the thread: private static void WriteFile() { Thread.Sleep(1000); Console.WriteLine("File Written."); } The call to Thread.Sleep(1000) delays thread execution. The parameter is specified in milliseconds, and 1000 means that this will cause the program to sleep for approximately 1 second.  This method happens to be static, but that's just part of this example, which you'll see is launched from the static Main method.  A thread could be instance or static.  Notice that the method does not have parameters and does not have a return type. As you know, the way to refer to a method is via a delegate.  There is a delegate named ThreadStart in System.Threading that refers to a method without parameters or return type, shown below: ThreadStart fileWriterHandlerDelegate = new ThreadStart(WriteFile); I'll show you the whole program below, but the ThreadStart instance above goes in the Main method. The thread uses the ThreadStart instance, fileWriterHandlerDelegate, to specify the method to execute on the thread: Thread fileWriter = new Thread(fileWriterHandlerDelegate); As shown above, the argument type for the Thread constructor is the ThreadStart delegate type. The fileWriterHandlerDelegate argument is an instance of the ThreadStart delegate type. This creates an instance of a thread and what code will execute, but the new thread instance, fileWriter, isn't running yet. You have to explicitly start it, like this: fileWriter.Start(); Now, the code in the WriteFile method is executing on a separate thread. Meanwhile, the main thread that started the fileWriter thread continues on it's own.  You have two threads running at the same time. Okay, I'm Starting to Get Glassy Eyed. How Does it All Fit Together? The example below is the whole program, pulling all the previous bits together. It's followed by its output and an explanation. using System; using System.Threading; namespace BasicThread { class Program { static void Main() { ThreadStart fileWriterHandlerDelegate = new ThreadStart(WriteFile); Thread fileWriter = new Thread(fileWriterHandlerDelegate); Console.WriteLine("Starting FileWriter"); fileWriter.Start(); Console.WriteLine("Called FileWriter"); Console.ReadKey(); } private static void WriteFile() { Thread.Sleep(1000); Console.WriteLine("File Written"); } } } And here's the output: Starting FileWriter Called FileWriter File Written So, Why are the Printouts Backwards? The output above corresponds to Console.Writeline statements in the program, with the second and third seemingly reversed. In a single-threaded program, "File Written" would print before "Called FileWriter". However, this is a multi-threaded (2 or more threads) program.  In multi-threading, you can't make any assumptions about when a given thread will run.  In this case, I added the Sleep statement to the WriteFile method to greatly increase the chances that the message from the main thread will print first. Without the Thread.Sleep, you could run this on a system with multiple cores and/or multiple processors and potentially get different results each time. Interesting Tangent but What Should I Get Out of All This? Going back to the main point, launching the WriteFile method on a separate thread made the program more responsive.  The file writing logic ran for a while, but the main thread returned to the user, as demonstrated by the print out of "Called FileWriter".  When the file write finished, it let the user know via another print statement. This was a very efficient use of CPU resources that made for a more pleasant user experience. Joe

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  • Namespaces are obsolete

    - by Bertrand Le Roy
    To those of us who have been around for a while, namespaces have been part of the landscape. One could even say that they have been defining the large-scale features of the landscape in question. However, something happened fairly recently that I think makes this venerable structure obsolete. Before I explain this development and why it’s a superior concept to namespaces, let me recapitulate what namespaces are and why they’ve been so good to us over the years… Namespaces are used for a few different things: Scope: a namespace delimits the portion of code where a name (for a class, sub-namespace, etc.) has the specified meaning. Namespaces are usually the highest-level scoping structures in a software package. Collision prevention: name collisions are a universal problem. Some systems, such as jQuery, wave it away, but the problem remains. Namespaces provide a reasonable approach to global uniqueness (and in some implementations such as XML, enforce it). In .NET, there are ways to relocate a namespace to avoid those rare collision cases. Hierarchy: programmers like neat little boxes, and especially boxes within boxes within boxes. For some reason. Regular human beings on the other hand, tend to think linearly, which is why the Windows explorer for example has tried in a few different ways to flatten the file system hierarchy for the user. 1 is clearly useful because we need to protect our code from bleeding effects from the rest of the application (and vice versa). A language with only global constructs may be what some of us started programming on, but it’s not desirable in any way today. 2 may not be always reasonably worth the trouble (jQuery is doing fine with its global plug-in namespace), but we still need it in many cases. One should note however that globally unique names are not the only possible implementation. In fact, they are a rather extreme solution. What we really care about is collision prevention within our application. What happens outside is irrelevant. 3 is, more than anything, an aesthetical choice. A common convention has been to encode the whole pedigree of the code into the namespace. Come to think about it, we never think we need to import “Microsoft.SqlServer.Management.Smo.Agent” and that would be very hard to remember. What we want to do is bring nHibernate into our app. And this is precisely what you’ll do with modern package managers and module loaders. I want to take the specific example of RequireJS, which is commonly used with Node. Here is how you import a module with RequireJS: var http = require("http"); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This is of course importing a HTTP stack module into the code. There is no noise here. Let’s break this down. Scope (1) is provided by the one scoping mechanism in JavaScript: the closure surrounding the module’s code. Whatever scoping mechanism is provided by the language would be fine here. Collision prevention (2) is very elegantly handled. Whereas relocating is an afterthought, and an exceptional measure with namespaces, it is here on the frontline. You always relocate, using an extremely familiar pattern: variable assignment. We are very much used to managing our local variable names and any possible collision will get solved very easily by picking a different name. Wait a minute, I hear some of you say. This is only taking care of collisions on the client-side, on the left of that assignment. What if I have two libraries with the name “http”? Well, You can better qualify the path to the module, which is what the require parameter really is. As for hierarchical organization, you don’t really want that, do you? RequireJS’ module pattern does elegantly cover the bases that namespaces used to cover, but it also promotes additional good practices. First, it promotes usage of self-contained, single responsibility units of code through the closure-based, stricter scoping mechanism. Namespaces are somewhat more porous, as using/import statements can be used bi-directionally, which leads us to my second point… Sane dependency graphs are easier to achieve and sustain with such a structure. With namespaces, it is easy to construct dependency cycles (that’s bad, mmkay?). With this pattern, the equivalent would be to build mega-components, which are an easier problem to spot than a decay into inter-dependent namespaces, for which you need specialized tools. I really like this pattern very much, and I would like to see more environments implement it. One could argue that dependency injection has some commonalities with this for example. What do you think? This is the half-baked result of some morning shower reflections, and I’d love to read your thoughts about it. What am I missing?

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  • Oracle NoSQL Database Exceeds 1 Million Mixed YCSB Ops/Sec

    - by Charles Lamb
    We ran a set of YCSB performance tests on Oracle NoSQL Database using SSD cards and Intel Xeon E5-2690 CPUs with the goal of achieving 1M mixed ops/sec on a 95% read / 5% update workload. We used the standard YCSB parameters: 13 byte keys and 1KB data size (1,102 bytes after serialization). The maximum database size was 2 billion records, or approximately 2 TB of data. We sized the shards to ensure that this was not an "in-memory" test (i.e. the data portion of the B-Trees did not fit into memory). All updates were durable and used the "simple majority" replica ack policy, effectively 'committing to the network'. All read operations used the Consistency.NONE_REQUIRED parameter allowing reads to be performed on any replica. In the past we have achieved 100K ops/sec using SSD cards on a single shard cluster (replication factor 3) so for this test we used 10 shards on 15 Storage Nodes with each SN carrying 2 Rep Nodes and each RN assigned to its own SSD card. After correcting a scaling problem in YCSB, we blew past the 1M ops/sec mark with 8 shards and proceeded to hit 1.2M ops/sec with 10 shards.  Hardware Configuration We used 15 servers, each configured with two 335 GB SSD cards. We did not have homogeneous CPUs across all 15 servers available to us so 12 of the 15 were Xeon E5-2690, 2.9 GHz, 2 sockets, 32 threads, 193 GB RAM, and the other 3 were Xeon E5-2680, 2.7 GHz, 2 sockets, 32 threads, 193 GB RAM.  There might have been some upside in having all 15 machines configured with the faster CPU, but since CPU was not the limiting factor we don't believe the improvement would be significant. The client machines were Xeon X5670, 2.93 GHz, 2 sockets, 24 threads, 96 GB RAM. Although the clients had 96 GB of RAM, neither the NoSQL Database or YCSB clients require anywhere near that amount of memory and the test could have just easily been run with much less. Networking was all 10GigE. YCSB Scaling Problem We made three modifications to the YCSB benchmark. The first was to allow the test to accommodate more than 2 billion records (effectively int's vs long's). To keep the key size constant, we changed the code to use base 32 for the user ids. The second change involved to the way we run the YCSB client in order to make the test itself horizontally scalable.The basic problem has to do with the way the YCSB test creates its Zipfian distribution of keys which is intended to model "real" loads by generating clusters of key collisions. Unfortunately, the percentage of collisions on the most contentious keys remains the same even as the number of keys in the database increases. As we scale up the load, the number of collisions on those keys increases as well, eventually exceeding the capacity of the single server used for a given key.This is not a workload that is realistic or amenable to horizontal scaling. YCSB does provide alternate key distribution algorithms so this is not a shortcoming of YCSB in general. We decided that a better model would be for the key collisions to be limited to a given YCSB client process. That way, as additional YCSB client processes (i.e. additional load) are added, they each maintain the same number of collisions they encounter themselves, but do not increase the number of collisions on a single key in the entire store. We added client processes proportionally to the number of records in the database (and therefore the number of shards). This change to the use of YCSB better models a use case where new groups of users are likely to access either just their own entries, or entries within their own subgroups, rather than all users showing the same interest in a single global collection of keys. If an application finds every user having the same likelihood of wanting to modify a single global key, that application has no real hope of getting horizontal scaling. Finally, we used read/modify/write (also known as "Compare And Set") style updates during the mixed phase. This uses versioned operations to make sure that no updates are lost. This mode of operation provides better application behavior than the way we have typically run YCSB in the past, and is only practical at scale because we eliminated the shared key collision hotspots.It is also a more realistic testing scenario. To reiterate, all updates used a simple majority replica ack policy making them durable. Scalability Results In the table below, the "KVS Size" column is the number of records with the number of shards and the replication factor. Hence, the first row indicates 400m total records in the NoSQL Database (KV Store), 2 shards, and a replication factor of 3. The "Clients" column indicates the number of YCSB client processes. "Threads" is the number of threads per process with the total number of threads. Hence, 90 threads per YCSB process for a total of 360 threads. The client processes were distributed across 10 client machines. Shards KVS Size Clients Mixed (records) Threads OverallThroughput(ops/sec) Read Latencyav/95%/99%(ms) Write Latencyav/95%/99%(ms) 2 400m(2x3) 4 90(360) 302,152 0.76/1/3 3.08/8/35 4 800m(4x3) 8 90(720) 558,569 0.79/1/4 3.82/16/45 8 1600m(8x3) 16 90(1440) 1,028,868 0.85/2/5 4.29/21/51 10 2000m(10x3) 20 90(1800) 1,244,550 0.88/2/6 4.47/23/53

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  • Using Unity – Part 4

    - by nmarun
    In this part, I’ll be discussing about constructor and property or setter injection. I’ve created a new class – Product3: 1: public class Product3 : IProduct 2: { 3: public string Name { get; set; } 4: [Dependency] 5: public IDistributor Distributor { get; set; } 6: public ILogger Logger { get; set; } 7:  8: public Product3(ILogger logger) 9: { 10: Logger = logger; 11: Name = "Product 1"; 12: } 13:  14: public string WriteProductDetails() 15: { 16: StringBuilder productDetails = new StringBuilder(); 17: productDetails.AppendFormat("{0}<br/>", Name); 18: productDetails.AppendFormat("{0}<br/>", Logger.WriteLog()); 19: productDetails.AppendFormat("{0}<br/>", Distributor.WriteDistributorDetails()); 20: return productDetails.ToString(); 21: } 22: } This version has a property of type IDistributor and takes a constructor parameter of type ILogger. The IDistributor property has a Dependency attribute (Microsoft.Practices.Unity namespace) applied to it. IDistributor and its implementation are shown below: 1: public interface IDistributor 2: { 3: string WriteDistributorDetails(); 4: } 5:  6: public class Distributor : IDistributor 7: { 8: public List<string> DistributorNames = new List<string>(); 9:  10: public Distributor() 11: { 12: DistributorNames.Add("Distributor1"); 13: DistributorNames.Add("Distributor2"); 14: DistributorNames.Add("Distributor3"); 15: DistributorNames.Add("Distributor4"); 16: } 17: public string WriteDistributorDetails() 18: { 19: StringBuilder distributors = new StringBuilder(); 20: for (int i = 0; i < DistributorNames.Count; i++) 21: { 22: distributors.AppendFormat("{0}<br/>", DistributorNames[i]); 23: } 24: return distributors.ToString(); 25: } 26: } ILogger and the FileLogger have the following definition: 1: public interface ILogger 2: { 3: string WriteLog(); 4: } 5:  6: public class FileLogger : ILogger 7: { 8: public string WriteLog() 9: { 10: return string.Format("Type: {0}", GetType()); 11: } 12: } The Unity container creates an instance of the dependent class (the Distributor class) within the scope of the target object (an instance of Product3 class that will be called by doing a Resolve<IProduct>() in the calling code) and assign this dependent object to the attributed property of the target object. To add to it, property injection is a form of optional injection of dependent objects.The dependent object instance is generated before the container returns the target object. Unlike constructor injection, you must apply the appropriate attribute in the target class to initiate property injection. Let’s see how to change the config file to make this work. The first step is to add all the type aliases: 1: <typeAlias alias="Product3" type="ProductModel.Product3, ProductModel"/> 2: <typeAlias alias="ILogger" type="ProductModel.ILogger, ProductModel"/> 3: <typeAlias alias="FileLogger" type="ProductModel.FileLogger, ProductModel"/> 4: <typeAlias alias="IDistributor" type="ProductModel.IDistributor, ProductModel"/> 5: <typeAlias alias="Distributor" type="ProductModel.Distributor, ProductModel"/> Now define mappings for these aliases: 1: <type type="ILogger" mapTo="FileLogger" /> 2: <type type="IDistributor" mapTo="Distributor" /> Next step is to define the constructor and property injection in the config file: 1: <type type="IProduct" mapTo="Product3" name="ComplexProduct"> 2: <typeConfig extensionType="Microsoft.Practices.Unity.Configuration.TypeInjectionElement, Microsoft.Practices.Unity.Configuration"> 3: <constructor> 4: <param name="logger" parameterType="ILogger" /> 5: </constructor> 6: <property name="Distributor" propertyType="IDistributor"> 7: <dependency /> 8: </property> 9: </typeConfig> 10: </type> There you see a constructor element that tells there’s a property named ‘logger’ that is of type ILogger. By default, the type of ILogger gets resolved to type FileLogger. There’s also a property named ‘Distributor’ which is of type IDistributor and which will get resolved to type Distributor. On the calling side, I’ve added a new button, whose click event does the following: 1: protected void InjectionButton_Click(object sender, EventArgs e) 2: { 3: unityContainer.RegisterType<IProduct, Product3>(); 4: IProduct product3 = unityContainer.Resolve<IProduct>(); 5: productDetailsLabel.Text = product3.WriteProductDetails(); 6: } This renders the following output: This completes the part for constructor and property injection. In the next blog, I’ll talk about Arrays and Generics. Please see the code used here.

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  • Are IE9 really good ?

    - by anirudha
    IE9 started a campaign for kill IE6 from the core because they know that IE6 is a big trouble or  problem for them for promote 9 version of IE. so they started a campaign for killing IE6. next time they kill IE 7 , 8,9 whenever they found this old version have a big problem for them to promote next version of IE.   Why they not make a update system who automatically update the browser and tell user to restart and update goes installed in the user system. well IE9 should learn from all other that they have very well design auto-update system who never give user in trouble that your browser goes old. Chrome and Firefox both update themselves and say user restart to enjoy another good version. in IE6 a big problem is that updates. no one sure that they installed new version of IE6 without any hassles and update goes install without any problem because they really know or care about “you need this to install this and this for this” so they thing “why I update IE whenever I am unsure that my browser goes update and I have no problem again” so they do nothing because their work done with no problem because common person used high profile application who work even in IE6. so they do nothing.    IE6 countdown website have designed a banner for warn or force user to upgrade to next version of IE. well there is no good reason for put the banner on website some of reason are:-   Windows 7 comes with pre-installed IE8 and Vista comes with upgrade version them IE6 so that is sure that you force a user who have Windows XP [luna] and if they want to upgrade IE then they can get IE8 not version 9 because IE9 is design for Windows 7 or Vista Service pack 2. so What is the use of update when user still have a outdate version too because IE8 is old version and not have any capability of HTML5 so forcing user by using the banner have no sense. I am not know why they all listed on website put the banner on their own website. it’s good that you offer user what they want instead of giving them a outdate version of IE again. My means to give a user list of browser they can try to enhance their browser experience instead of only IE.   IE9 build upon WPF and they spent more time on using WPF in IE instead of making user experience browser.  many thing is designed wrongly in IE first thing is tabs. the tabs in chrome are bigger and easily to move and same in Firefox even not have smooth tabbing. IE have same tabbing as chrome have but leak a point that it’s too small. if you really  want to move then sometime they create a problem that they going elsewhere from the current instance of IE.   Chrome have a big buttons, tabs and menu to enhance browser experience and Firefox have a good feature that you can make them bigger or small. you can put the icon for add-ons on the toolbar for easily use but IE have no relation with customization so we never can thinking about that.   When chrome provide lot’s of extensions and a  webstore for browser application and same feature in Firefox can be seen then there is no plugin in IE. really you can see their IE addons Website where no plugin listed for web development. even in the category or tag. as a response from many blog there is new for developer that new version of IE9 developer tool. well IE9 have three new tabs a blogger tell on their blog. when I trying them I found many thing but I still unable to edit the Css from the HTML tab and no plugin I found I can get to enhance IE9 web development. something more other provide never IE9 give me like personas , customization , browser extension or any other they used to tell a small thing customization  .   IE9 still have some problem with JavaScript that when I use Firefox and chrome and logout in both then my cookie is deleted but in IE it’s not done. it’s show me that IE9 still have different from other not for good thing even some bad thing too. When I trying to read a article that is written in Hindi using Unicode font I found that they show many thing misspelled. there is three Sha in Hindi but they all goes wrong in IE. the misprint thing is not that the writing  for the articles goes wrong. it’s problem or browser to rendering a font. the Firefox and chrome not give me this problem even opera render the font in italic style by decrease the font-size but all those work perfect.   in Pwn2Own the apple’s safari  and IE9 both are hacked. this is a awesome news for whose who thing that  open-source is lose in  Security and close-source is highly-secured software. well this is not a good parameter for talking about software. it’s should depend how much application tested and used. because more testing and more use of application make them better.   I  appreciate IE to making their new version 9 and good luck for them. there is a another matter that I personally found nothing on them.

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  • Why do I get an exception when playing multiple sound instances?

    - by Boreal
    Right now, I'm adding a rudimentary sound engine to my game. So far, I am able to load in a WAV file and play it once, then free up the memory when I close the game. However, the game crashes with a nice ArgumentOutOfBoundsException when I try to play another sound instance. Specified argument was out of the range of valid values. Parameter name: readLength I'm following this tutorial pretty much exactly, but I still keep getting the aforementioned error. Here's my sound-related code. /// <summary> /// Manages all sound instances. /// </summary> public static class Audio { static XAudio2 device; static MasteringVoice master; static List<SoundInstance> instances; /// <summary> /// The XAudio2 device. /// </summary> internal static XAudio2 Device { get { return device; } } /// <summary> /// Initializes the audio device and master track. /// </summary> internal static void Initialize() { device = new XAudio2(); master = new MasteringVoice(device); instances = new List<SoundInstance>(); } /// <summary> /// Releases all XA2 resources. /// </summary> internal static void Shutdown() { foreach(SoundInstance i in instances) i.Dispose(); master.Dispose(); device.Dispose(); } /// <summary> /// Registers a sound instance with the system. /// </summary> /// <param name="instance">Sound instance</param> internal static void AddInstance(SoundInstance instance) { instances.Add(instance); } /// <summary> /// Disposes any sound instance that has stopped playing. /// </summary> internal static void Update() { List<SoundInstance> temp = new List<SoundInstance>(instances); foreach(SoundInstance i in temp) if(!i.Playing) { i.Dispose(); instances.Remove(i); } } } /// <summary> /// Loads sounds from various files. /// </summary> internal class SoundLoader { /// <summary> /// Loads a .wav sound file. /// </summary> /// <param name="format">The decoded format will be sent here</param> /// <param name="buffer">The data will be sent here</param> /// <param name="soundName">The path to the WAV file</param> internal static void LoadWAV(out WaveFormat format, out AudioBuffer buffer, string soundName) { WaveStream wave = new WaveStream(soundName); format = wave.Format; buffer = new AudioBuffer(); buffer.AudioData = wave; buffer.AudioBytes = (int)wave.Length; buffer.Flags = BufferFlags.EndOfStream; } } /// <summary> /// Manages the data for a single sound. /// </summary> public class Sound : IAsset { WaveFormat format; AudioBuffer buffer; /// <summary> /// Loads a sound from a file. /// </summary> /// <param name="soundName">The path to the sound file</param> /// <returns>Whether the sound loaded successfully</returns> public bool Load(string soundName) { if(soundName.EndsWith(".wav")) SoundLoader.LoadWAV(out format, out buffer, soundName); else return false; return true; } /// <summary> /// Plays the sound. /// </summary> public void Play() { Audio.AddInstance(new SoundInstance(format, buffer)); } /// <summary> /// Unloads the sound from memory. /// </summary> public void Unload() { buffer.Dispose(); } } /// <summary> /// Manages a single sound instance. /// </summary> public class SoundInstance { SourceVoice source; bool playing; /// <summary> /// Whether the sound is currently playing. /// </summary> public bool Playing { get { return playing; } } /// <summary> /// Starts a new instance of a sound. /// </summary> /// <param name="format">Format of the sound</param> /// <param name="buffer">Buffer holding sound data</param> internal SoundInstance(WaveFormat format, AudioBuffer buffer) { source = new SourceVoice(Audio.Device, format); source.BufferEnd += (s, e) => playing = false; source.Start(); source.SubmitSourceBuffer(buffer); // THIS IS WHERE THE EXCEPTION IS THROWN playing = true; } /// <summary> /// Releases memory used by the instance. /// </summary> internal void Dispose() { source.Dispose(); } } The exception occurs on line 156 when I am playing the sound: source.SubmitSourceBuffer(buffer);

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  • The sign of a true manager is delegation (C# style)

    - by MarkPearl
    Today I thought I would write a bit about delegates in C#. Up till recently I have managed to side step any real understanding of what delegates do and why they are useful – I mean, I know roughly what they do and have used them a lot, but I have never really got down dirty with them and mucked about. Recently however with my renewed interest in Silverlight delegates came up again as a possible solution to a particular problem, and suddenly I found myself opening a bland little console application to just see exactly how far I could take delegates with my limited knowledge. So, let’s first look at the MSDN definition of delegates… A delegate declaration defines a reference type that can be used to encapsulate a method with a specific signature. A delegate instance encapsulates a static or an instance method. Delegates are roughly similar to function pointers in C++; however, delegates are type-safe and secure. Well, don’t you love MSDN for such a useful definition. I must give it credit though… later on it really explains it a bit better by saying “A delegate lets you pass a function as a parameter. The type safety of delegates requires the function you pass as a delegate to have the same signature as the delegate declaration.” A little more reading up on delegates mentions that delegates are similar to interfaces in that they enable the separation of specification and implementation. A delegate declares a single method, while an interface declares a group of methods. So enough reading - lets look at some code and see a basic example of a delegate… Let’s assume we have a console application with a simple delegate declared called AdjustValue like below… class Program { private delegate int AdjustValue(int val); static void Main(string[] args) { } } In a sense, all we have said is that we will be creating one or more methods that follow the same pattern as AdjustValue – i.e. they will take one input value of type int and return an integer. We could then expand our code to have various methods that match the structure of our delegate AdjustValue (remember the structure is int xxx (int xxx)) class Program { private delegate int AdjustValue(int val); private static int Dbl(int val) { return val * 2; } private static int AlwaysOne(int val) { return 1; } static void Main(string[] args) { } }  Above I have expanded my project to have two methods, one called Dbl and the other AlwaysOne. Dbl always returns double the input val and AlwaysOne always returns 1. I could now declare a variable and assign it to be one of those functions, like the following… class Program { private delegate int AdjustValue(int val); private static int Dbl(int val) { return val * 2; } private static int AlwaysOne(int val) { return 1; } static void Main(string[] args) { AdjustValue myDelegate; myDelegate = Dbl; Console.WriteLine(myDelegate(1).ToString()); Console.ReadLine(); } } In this instance I have declared an instance of the AdjustValue delegate called myDelegate; I have then told myDelegate to point to the method Dbl, and then called myDelegate(1). What would the result be? Yes, in this instance it would be exactly the same as me calling the following code… static void Main(string[] args) { Console.WriteLine(Dbl(1).ToString()); Console.ReadLine(); }   So why all the extra work for delegates when we could just do what we did above and call the method directly? Well… that separation of specification to implementation comes to mind. So, this all seems pretty simple. Let’s take a slightly more complicated variation to the console application. Assume that my project is the same as the one previously except that my main method is adjusted as follows… static void Main(string[] args) { AdjustValue myDelegate; myDelegate = Dbl; myDelegate = AlwaysOne; Console.WriteLine(myDelegate(1).ToString()); Console.ReadLine(); } What would happen in this scenario? Quite simply “1” would be written to the console, the reason being that myDelegate was last pointing to the AlwaysOne method before it was called. Make sense? In a way, the myDelegate is a variable method that can be swapped and changed when needed. Let’s make the code a little more confusing by using a delegate in the declaration of another delegate as shown below… class Program { private delegate int AdjustValue(InputValue val); private delegate int InputValue(); private static int Dbl(InputValue val) { return val()*2; } private static int GetInputVal() { Console.WriteLine("Enter a whole number : "); return Convert.ToInt32(Console.ReadLine()); } static void Main(string[] args) { AdjustValue myDelegate; myDelegate = Dbl; Console.WriteLine(myDelegate(GetInputVal).ToString()); Console.ReadLine(); } }   Now it gets really interesting because it looks like we have passed a method into a function in the main method by declaring… Console.WriteLine(myDelegate(GetInputVal).ToString()); So, what it the output? Well, try take a guess on what will happen – then copy the code and see if you got it right. Well that brings me to the end of this short explanation of Delegates. Hopefully it made sense!

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  • How to make creating viewmodels at runtime less painfull

    - by Mr Happy
    I apologize for the long question, it reads a bit as a rant, but I promise it's not! I've summarized my question(s) below In the MVC world, things are straightforward. The Model has state, the View shows the Model, and the Controller does stuff to/with the Model (basically), a controller has no state. To do stuff the Controller has some dependencies on web services, repository, the lot. When you instantiate a controller you care about supplying those dependencies, nothing else. When you execute an action (method on Controller), you use those dependencies to retrieve or update the Model or calling some other domain service. If there's any context, say like some user wants to see the details of a particular item, you pass the Id of that item as parameter to the Action. Nowhere in the Controller is there any reference to any state. So far so good. Enter MVVM. I love WPF, I love data binding. I love frameworks that make data binding to ViewModels even easier (using Caliburn Micro a.t.m.). I feel things are less straightforward in this world though. Let's do the exercise again: the Model has state, the View shows the ViewModel, and the ViewModel does stuff to/with the Model (basically), a ViewModel does have state! (to clarify; maybe it delegates all the properties to one or more Models, but that means it must have a reference to the model one way or another, which is state in itself) To do stuff the ViewModel has some dependencies on web services, repository, the lot. When you instantiate a ViewModel you care about supplying those dependencies, but also the state. And this, ladies and gentlemen, annoys me to no end. Whenever you need to instantiate a ProductDetailsViewModel from the ProductSearchViewModel (from which you called the ProductSearchWebService which in turn returned IEnumerable<ProductDTO>, everybody still with me?), you can do one of these things: call new ProductDetailsViewModel(productDTO, _shoppingCartWebService /* dependcy */);, this is bad, imagine 3 more dependencies, this means the ProductSearchViewModel needs to take on those dependencies as well. Also changing the constructor is painfull. call _myInjectedProductDetailsViewModelFactory.Create().Initialize(productDTO);, the factory is just a Func, they are easily generated by most IoC frameworks. I think this is bad because Init methods are a leaky abstraction. You also can't use the readonly keyword for fields that are set in the Init method. I'm sure there are a few more reasons. call _myInjectedProductDetailsViewModelAbstractFactory.Create(productDTO); So... this is the pattern (abstract factory) that is usually recommended for this type of problem. I though it was genious since it satisfies my craving for static typing, until I actually started using it. The amount of boilerplate code is I think too much (you know, apart from the ridiculous variable names I get use). For each ViewModel that needs runtime parameters you'll get two extra files (factory interface and implementation), and you need to type the non-runtime dependencies like 4 extra times. And each time the dependencies change, you get to change it in the factory as well. It feels like I don't even use an DI container anymore. (I think Castle Windsor has some kind of solution for this [with it's own drawbacks, correct me if I'm wrong]). do something with anonymous types or dictionary. I like my static typing. So, yeah. Mixing state and behavior in this way creates a problem which don't exist at all in MVC. And I feel like there currently isn't a really adequate solution for this problem. Now I'd like to observe some things: People actually use MVVM. So they either don't care about all of the above, or they have some brilliant other solution. I haven't found an indepth example of MVVM with WPF. For example, the NDDD-sample project immensely helped me understand some DDD concepts. I'd really like it if someone could point me in the direction of something similar for MVVM/WPF. Maybe I'm doing MVVM all wrong and I should turn my design upside down. Maybe I shouldn't have this problem at all. Well I know other people have asked the same question so I think I'm not the only one. To summarize Am I correct to conclude that having the ViewModel being an integration point for both state and behavior is the reason for some difficulties with the MVVM pattern as a whole? Is using the abstract factory pattern the only/best way to instantiate a ViewModel in a statically typed way? Is there something like an in depth reference implementation available? Is having a lot of ViewModels with both state/behavior a design smell?

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  • Using Subjects to Deploy Queries Dynamically

    - by Roman Schindlauer
    In the previous blog posting, we showed how to construct and deploy query fragments to a StreamInsight server, and how to re-use them later. In today’s posting we’ll integrate this pattern into a method of dynamically composing a new query with an existing one. The construct that enables this scenario in StreamInsight V2.1 is a Subject. A Subject lets me create a junction element in an existing query that I can tap into while the query is running. To set this up as an end-to-end example, let’s first define a stream simulator as our data source: var generator = myApp.DefineObservable(     (TimeSpan t) => Observable.Interval(t).Select(_ => new SourcePayload())); This ‘generator’ produces a new instance of SourcePayload with a period of t (system time) as an IObservable. SourcePayload happens to have a property of type double as its payload data. Let’s also define a sink for our example—an IObserver of double values that writes to the console: var console = myApp.DefineObserver(     (string label) => Observer.Create<double>(e => Console.WriteLine("{0}: {1}", label, e)))     .Deploy("ConsoleSink"); The observer takes a string as parameter which is used as a label on the console, so that we can distinguish the output of different sink instances. Note that we also deploy this observer, so that we can retrieve it later from the server from a different process. Remember how we defined the aggregation as an IQStreamable function in the previous article? We will use that as well: var avg = myApp     .DefineStreamable((IQStreamable<SourcePayload> s, TimeSpan w) =>         from win in s.TumblingWindow(w)         select win.Avg(e => e.Value))     .Deploy("AverageQuery"); Then we define the Subject, which acts as an observable sequence as well as an observer. Thus, we can feed a single source into the Subject and have multiple consumers—that can come and go at runtime—on the other side: var subject = myApp.CreateSubject("Subject", () => new Subject<SourcePayload>()); Subject are always deployed automatically. Their name is used to retrieve them from a (potentially) different process (see below). Note that the Subject as we defined it here doesn’t know anything about temporal streams. It is merely a sequence of SourcePayloads, without any notion of StreamInsight point events or CTIs. So in order to compose a temporal query on top of the Subject, we need to 'promote' the sequence of SourcePayloads into an IQStreamable of point events, including CTIs: var stream = subject.ToPointStreamable(     e => PointEvent.CreateInsert<SourcePayload>(e.Timestamp, e),     AdvanceTimeSettings.StrictlyIncreasingStartTime); In a later posting we will show how to use Subjects that have more awareness of time and can be used as a junction between QStreamables instead of IQbservables. Having turned the Subject into a temporal stream, we can now define the aggregate on this stream. We will use the IQStreamable entity avg that we defined above: var longAverages = avg(stream, TimeSpan.FromSeconds(5)); In order to run the query, we need to bind it to a sink, and bind the subject to the source: var standardQuery = longAverages     .Bind(console("5sec average"))     .With(generator(TimeSpan.FromMilliseconds(300)).Bind(subject)); Lastly, we start the process: standardQuery.Run("StandardProcess"); Now we have a simple query running end-to-end, producing results. What follows next is the crucial part of tapping into the Subject and adding another query that runs in parallel, using the same query definition (the “AverageQuery”) but with a different window length. We are assuming that we connected to the same StreamInsight server from a different process or even client, and thus have to retrieve the previously deployed entities through their names: // simulate the addition of a 'fast' query from a separate server connection, // by retrieving the aggregation query fragment // (instead of simply using the 'avg' object) var averageQuery = myApp     .GetStreamable<IQStreamable<SourcePayload>, TimeSpan, double>("AverageQuery"); // retrieve the input sequence as a subject var inputSequence = myApp     .GetSubject<SourcePayload, SourcePayload>("Subject"); // retrieve the registered sink var sink = myApp.GetObserver<string, double>("ConsoleSink"); // turn the sequence into a temporal stream var stream2 = inputSequence.ToPointStreamable(     e => PointEvent.CreateInsert<SourcePayload>(e.Timestamp, e),     AdvanceTimeSettings.StrictlyIncreasingStartTime); // apply the query, now with a different window length var shortAverages = averageQuery(stream2, TimeSpan.FromSeconds(1)); // bind new sink to query and run it var fastQuery = shortAverages     .Bind(sink("1sec average"))     .Run("FastProcess"); The attached solution demonstrates the sample end-to-end. Regards, The StreamInsight Team

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  • C++ strongly typed typedef

    - by Kian
    I've been trying to think of a way of declaring strongly typed typedefs, to catch a certain class of bugs in the compilation stage. It's often the case that I'll typedef an int into several types of ids, or a vector to position or velocity: typedef int EntityID; typedef int ModelID; typedef Vector3 Position; typedef Vector3 Velocity; This can make the intent of code more clear, but after a long night of coding one might make silly mistakes like comparing different kinds of ids, or adding a position to a velocity perhaps. EntityID eID; ModelID mID; if ( eID == mID ) // <- Compiler sees nothing wrong { /*bug*/ } Position p; Velocity v; Position newP = p + v; // bug, meant p + v*s but compiler sees nothing wrong Unfortunately, suggestions I've found for strongly typed typedefs include using boost, which at least for me isn't a possibility (I do have c++11 at least). So after a bit of thinking, I came upon this idea, and wanted to run it by someone. First, you declare the base type as a template. The template parameter isn't used for anything in the definition, however: template < typename T > class IDType { unsigned int m_id; public: IDType( unsigned int const& i_id ): m_id {i_id} {}; friend bool operator==<T>( IDType<T> const& i_lhs, IDType<T> const& i_rhs ); }; Friend functions actually need to be forward declared before the class definition, which requires a forward declaration of the template class. We then define all the members for the base type, just remembering that it's a template class. Finally, when we want to use it, we typedef it as: class EntityT; typedef IDType<EntityT> EntityID; class ModelT; typedef IDType<ModelT> ModelID; The types are now entirely separate. Functions that take an EntityID will throw a compiler error if you try to feed them a ModelID instead, for example. Aside from having to declare the base types as templates, with the issues that entails, it's also fairly compact. I was hoping anyone had comments or critiques about this idea? One issue that came to mind while writing this, in the case of positions and velocities for example, would be that I can't convert between types as freely as before. Where before multiplying a vector by a scalar would give another vector, so I could do: typedef float Time; typedef Vector3 Position; typedef Vector3 Velocity; Time t = 1.0f; Position p = { 0.0f }; Velocity v = { 1.0f, 0.0f, 0.0f }; Position newP = p + v*t; With my strongly typed typedef I'd have to tell the compiler that multypling a Velocity by a Time results in a Position. class TimeT; typedef Float<TimeT> Time; class PositionT; typedef Vector3<PositionT> Position; class VelocityT; typedef Vector3<VelocityT> Velocity; Time t = 1.0f; Position p = { 0.0f }; Velocity v = { 1.0f, 0.0f, 0.0f }; Position newP = p + v*t; // Compiler error To solve this, I think I'd have to specialize every conversion explicitly, which can be kind of a bother. On the other hand, this limitation can help prevent other kinds of errors (say, multiplying a Velocity by a Distance, perhaps, which wouldn't make sense in this domain). So I'm torn, and wondering if people have any opinions on my original issue, or my approach to solving it.

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  • ?Exadata??????DBFS

    - by Liu Maclean(???)
    ?Exadata???DBFS ??????? 1. ??fuse RPM  [root@dm01db01 ~]# yum install fuse Loaded plugins: rhnplugin, security This system is not registered with ULN. ULN support will be disabled. Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package fuse.x86_64 0:2.7.4-8.0.1.el5 set to be updated --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================  Package                            Arch                                 Version                                         Repository                                Size ======================================================================================================================================================================== Installing:  fuse                               x86_64                               2.7.4-8.0.1.el5                                 el5_latest                                85 k Transaction Summary ======================================================================================================================================================================== Install       1 Package(s) Upgrade       0 Package(s) Total download size: 85 k Is this ok [y/N]: y Downloading Packages: fuse-2.7.4-8.0.1.el5.x86_64.rpm                                                                                                                  |  85 kB     00:00      Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction   Installing     : fuse                                                                                                                                             1/1  Installed:   fuse.x86_64 0:2.7.4-8.0.1.el5                                                                                                                                          [root@dm01db01 ~]# yum install fuse-libs Loaded plugins: rhnplugin, security This system is not registered with ULN. ULN support will be disabled. Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package fuse-libs.i386 0:2.7.4-8.0.1.el5 set to be updated ---> Package fuse-libs.x86_64 0:2.7.4-8.0.1.el5 set to be updated --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================  Package                                Arch                                Version                                       Repository                               Size ======================================================================================================================================================================== Installing:  fuse-libs                              i386                                2.7.4-8.0.1.el5                               el5_latest                               71 k  fuse-libs                              x86_64                              2.7.4-8.0.1.el5                               el5_latest                               70 k Transaction Summary ======================================================================================================================================================================== Install       2 Package(s) Upgrade       0 Package(s) Total download size: 141 k Is this ok [y/N]: y Downloading Packages: (1/2): fuse-libs-2.7.4-8.0.1.el5.x86_64.rpm                                                                                                      |  70 kB     00:00      (2/2): fuse-libs-2.7.4-8.0.1.el5.i386.rpm                                                                                                        |  71 kB     00:00      ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Total                                                                                                                                    71 kB/s | 141 kB     00:01      Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction   Installing     : fuse-libs                                                                                                                                        1/2    Installing     : fuse-libs                                                                                                                                        2/2  Installed:   fuse-libs.i386 0:2.7.4-8.0.1.el5                                                  fuse-libs.x86_64 0:2.7.4-8.0.1.el5                                                  Complete! [root@dm01db01 ~]# yum install fuse-devel Loaded plugins: rhnplugin, security This system is not registered with ULN. ULN support will be disabled. Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package fuse-devel.i386 0:2.7.4-8.0.1.el5 set to be updated ---> Package fuse-devel.x86_64 0:2.7.4-8.0.1.el5 set to be updated --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================  Package                                 Arch                                Version                                      Repository                               Size ======================================================================================================================================================================== Installing:  fuse-devel                              i386                                2.7.4-8.0.1.el5                              el5_latest                               28 k  fuse-devel                              x86_64                              2.7.4-8.0.1.el5                              el5_latest                               28 k Transaction Summary ======================================================================================================================================================================== Install       2 Package(s) Upgrade       0 Package(s) Total download size: 57 k Is this ok [y/N]: y Downloading Packages: (1/2): fuse-devel-2.7.4-8.0.1.el5.x86_64.rpm                                                                                                     |  28 kB     00:00      (2/2): fuse-devel-2.7.4-8.0.1.el5.i386.rpm                                                                                                       |  28 kB     00:00      ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Total                                                                                                                                    21 kB/s |  57 kB     00:02      Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction   Installing     : fuse-devel                                                                                                                                       1/2    Installing     : fuse-devel                                                                                                                                       2/2  Installed:   fuse-devel.i386 0:2.7.4-8.0.1.el5                                                 fuse-devel.x86_64 0:2.7.4-8.0.1.el5                                                 Complete! 2. ?? DBFS??? ?????? cd $ORACLE_HOME/rdbms/admin sqlplus / as sysdba Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP, Data Mining and Real Application Testing options SQL> @prvtfspi.plb Package body created. No errors. Package body created. No errors. ?????dbms_dbfs_sfs package  SQL> create tablespace dbfstbs datafile size 20g; Tablespace created. SQL> create user maclean_dbfs identified by oracle; User created. SQL> grant dba to maclean_dbfs; Grant succeeded. @@!!! SQL> grant  dbfs_role to maclean_dbfs; Grant succeeded. 3. ??DBFS SQL> conn maclean_dbfs/oracle Connected. SQL> @?/rdbms/admin/dbfs_create_filesystem.sql  dbfstbs mac_dbfs   No errors. -------- CREATE STORE: begin dbms_dbfs_sfs.createFilesystem(store_name => 'FS_MAC_DBFS', tbl_name => 'T_MAC_DBFS', tbl_tbs => 'dbfstbs', lob_tbs => 'dbfstbs', do_partition => false, partition_key => 1, do_compress => false, compression => '', do_dedup => false, do_encrypt => false); end; -------- REGISTER STORE: begin dbms_dbfs_content.registerStore(store_name=> 'FS_MAC_DBFS', provider_name => 'sample1', provider_package => 'dbms_dbfs_sfs'); end; -------- MOUNT STORE: begin dbms_dbfs_content.mountStore(store_name=>'FS_MAC_DBFS', store_mount=>'mac_dbfs'); end; -------- CHMOD STORE: declare m integer; begin m := dbms_fuse.fs_chmod('/mac_dbfs', 16895); end; No errors. 4.  ??mount point  [root@dm01db01 ~]# mkdir /dbfs [root@dm01db01 ~]# chown oracle:oinstall /dbfs 5. ??library path ?OS  # echo "/usr/local/lib" >> /etc/ld.so.conf.d/usr_local_lib.conf 6. ?????? export ORACLE_HOME=/s01/orabase/product/11.2.0/dbhome_1 [root@dm01db01 ~]# ln -s $ORACLE_HOME/lib/libclntsh.so.11.1 /usr/local/lib/libclntsh.so.11.1 [root@dm01db01 ~]#  ln -s $ORACLE_HOME/lib/libnnz11.so /usr/local/lib/libnnz11.so [root@dm01db01 ~]#  ln -s /lib64/libfuse.so.2 /usr/local/lib/libfuse.so.2 7. ??ldconfig  [root@dm01db01 ~]# ldconfig [root@dm01db01 ~]#  8. ??fusermount??????? [root@dm01db01 ~]#  chmod +x /usr/bin/fusermount [root@dm01db01 ~]#  ls -l /usr/bin/fusermount lrwxrwxrwx 1 root root 15 Sep  7 03:06 /usr/bin/fusermount -> /bin/fusermount [root@dm01db01 ~]#  ls -l /bin/fusermount -rwsr-x--x 1 root fuse 27072 Oct 17  2011 /bin/fusermount 9. ???????OS  dbfs_client maclean_dbfs@dm01db01:1521/orcl  /dbfs 10. ????nohup + &?????mount DBFS,???????????? [oracle@dm01db01 ~]$ echo "oracle"  >> dbfs_pw [oracle@dm01db01 ~]$ nohup dbfs_client maclean_dbfs@dm01db01:1521/orcl /dbfs < dbfs_pw & [oracle@dm01db01 ~]$ df -h Filesystem            Size  Used Avail Use% Mounted on /dev/mapper/VGExaDb-LVDbSys1                        30G   15G   14G  53% / /dev/sda1             502M   30M  447M   7% /boot /dev/mapper/VGExaDb-LVDbOra1                        99G   20G   75G  21% /u01 tmpfs                  81G     0   81G   0% /dev/shm dbfs-maclean_dbfs@orcl:/                        20G  120K   20G   1% /dbfs [oracle@dm01db01 ~]$ mount /dev/mapper/VGExaDb-LVDbSys1 on / type ext3 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) /dev/sda1 on /boot type ext3 (rw,nodev) /dev/mapper/VGExaDb-LVDbOra1 on /u01 type ext3 (rw,nodev) tmpfs on /dev/shm type tmpfs (rw,size=82052m) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) dbfs-maclean_dbfs@orcl:/ on /dbfs type fuse (rw,nosuid,nodev,max_read=1048576,default_permissions,user=oracle) [oracle@dm01db01 ~]$ ls -l /dbfs/ total 0 drwxrwxrwx 3 root root 0 Sep 14 05:11 mac_dbfs [oracle@nas ~]$ dbfs_client  --------MOUNT mode: usage: dbfs_client <db_user>@<db_server> [options] <mountpoint>   db_user:              Name of Database user that owns DBFS content repository filesystem(s)   db_server:            A valid connect string for Oracle database server                         (for example, hrdb_host:1521/hrservice)   mountpoint:           Path to mount Database File System(s)                         All the file systems owned by the database user will be seen at the mountpoint. DBFS options:   -o direct_io          Bypass the Linux page cache. Gives much better performance for large files.                         Programs in the file system cannot be executed with this option.                         This option is recommended when DBFS is used as an ETL staging area.   -o wallet             Run dbfs_client in background.                         Wallet must be configured to get credentials.   -o failover           dbfs_client fails over to surviving database instance with no data loss.                         Some performance cost on writes, especially for small files.   -o allow_root         Allows root access to the filesystem.                         This option requires setting 'user_allow_other' parameter in '/etc/fuse.conf'.   -o allow_other        Allows other users access to the file system.                         This option requires setting 'user_allow_other' parameter in '/etc/fuse.conf'.   -o rw                 Mount the filesystem read-write. [Default]   -o ro                 Mount the filesystem read-only. Files cannot be modified.   -o trace_file=STR     Tracing <filename> | 'syslog'   -o trace_level=N      Trace Level: 1->DEBUG, 2->INFO, 3->WARNING, 4->ERROR, 5->CRITICAL [Default: 4]   -h                    help   -V                    version --------COMMAND mode: Usage:     dbfs_client <db_user>@<db_server> --command command [switches] [arguments]             command:          Command to be executed, e.g., ls, cp, mkdir, rm            switches:         Switches are described below for each command.            arguments:        File names or directory names NOTE:      All database pathnames must be absolute and preceded by dbfs:/ Commands   ls            dbfs_client <db_user>@<db_server> --command ls [switches] target      Switches:              -a         Show all files including those starting with '.'            -l         Use a long listing format. In addition to the name of each file                       print the file type, permissions, size, user and group information            -R         List subdirectories recursively cp                     dbfs_client <db_user>@<db_server> --command cp [switches] source destination      Switches:              -r, -R      Copy a directory and its contents recursively into the destination directory rm                     dbfs_client <db_user>@<db_server> --command rm [switches] target      Switches:              -r, -R      Removes a directory and its contents recursively mkdir                  dbfs_client <db_user>@<db_server> --command mkdir directory_name Examples                     dbfs_client ETLUser@DBConnectString --command ls -l -a dbfs:/staging_area/directory1            dbfs_client ETLUser@DBConnectString --command cp -R  /tmp/1-Jan-2009-dump dbfs:/staging_area            dbfs_client ETLUser@DBConnectString --command rm dbfs:/staging_area/hello.txt            dbfs_client ETLUser@DBConnectString --command mkdir dbfs:/staging_area/directory2 [oracle@dm01db01 ~]$ ls -lh /tmp/largefile -rw-r--r-- 1 oracle oinstall 2.0G Sep 14 08:50 /tmp/largefile [oracle@dm01db01 ~]$ time dbfs_client  maclean_dbfs@dm01db01:1521/orcl --command cp /tmp/largefile dbfs:/mac_dbfs Password: /tmp/largefile -> dbfs:/mac_dbfs/largefile real    0m11.802s user    0m0.580s sys     0m2.375s ?Exadata?????2G?????? DBFS???11s => 200MB/s 

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  • Struts 1 ActionForm - retrieving a collection from pure HTML

    - by Yaneeve
    Hi all I have (just like the rest) inherited some struts 1 code. I have had need to add a few more pages to this project. What I cannot figure out is how to map several distinct but similarly natured input elements to the my ActionForm. Let me elaborate. I create a new <Input> element dynamically as the user inputs more and more items (I use the YUI autocomplete form element and for each entered input I add it as an input element to my form and draw a new YUI autocomplete - complex sounding, I know) So... My form looks a bit like (... after some prettifying and some such...): <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"> <title>My Cool App - Test Case Builder</title> <link rel="stylesheet" type="text/css" href="../script/yui/fonts/fonts-min.css" /> <link rel="stylesheet" type="text/css" href="../skins/myCoolApp/button/button.css" /> <link rel="stylesheet" type="text/css" href="../script/yui/autocomplete/assets/skins/sam/autocomplete.css" /> <link rel="stylesheet" type="text/css" media="screen" href="../skins/myCoolApp/testcase.css" /> <!-- YUI JAVA SCRIPTS --> <script type="text/javascript" src="../script/yui/yahoo-dom-event/yahoo-dom-event.js"></script> <script type="text/javascript" src="../script/yui/element/element-min.js"></script> <script type="text/javascript" src="../script/yui/button/button-min.js"></script> <script type="text/javascript" src="../script/yui/datasource/datasource-min.js"></script> <script type="text/javascript" src="../script/yui/autocomplete/autocomplete-min.js"></script> <!-- APP JAVA SCRIPTS --> <script type="text/javascript" src="../script/myCoolApp/myCoolApp.js" ></script> <script type="text/javascript" src="../script/myCoolApp/stack.js" ></script> <script type="text/javascript" src="../script/myCoolApp/testcase/testcase.js"></script> <script type="text/javascript" src="../script/myCoolApp/testcase/default-data.js" ></script> <script type="text/javascript" src="../script/myCoolApp/testcase/data-structs.js" ></script> <script type="text/javascript" src="../script/myCoolApp/testcase/ui-elements.js" ></script> </head> <body class="cf010"> <div id="wrap"> <div id="header"> <div id="main-header"> COOL APP </div> </div> <div id="main-body"> <div id="content"> <div class="col main"> <div id="main"> <form method="post" id="testcaseForm" class="typea" action=""> <fieldset> <legend>Test Case Builder</legend> <div id="tk1" class="tabcontrol"> <ul class="tabs"> <li class="first active"> <a href="#"> <span>General</span> </a> </li> <li class="last"> <a href="#"> <span>Parameters</span> </a> </li> </ul> <div id="tab0" class="tc-panel"> <dl class="cls9"> <dt> <label for="scenario">Choose Scenario:</label> </dt> <dd> <input type="text" id="scenario" name="scenario" class="text" /> <span id="scenarioToggle"></span> <div class="auto-complete" id="scenarioContainer"></div> </dd> <dt> <label for="ruleID">Choose Rule ID:</label> </dt> <dd> <input type="text" id="ruleID" name="ruleID" class="text" /> <span id="ruleIDToggle"></span> <div class="auto-complete" id="ruleIDContainer"></div> </dd> <dt> <label for="Test Case Name" accesskey="t"><span class="accesskey">T</span>est Case Name:</label> </dt> <dd> <input type="text" id="testCaseName" name="testCaseName" class="text" /> </dd> </dl> </div> <div id="tab1" class="tc-panel hidden"> <div class="toolbar" id="action-bar"> <ul> <li class="first"> <a title="select all" href="#" id="btmSelectAll" class="button"> <span>select all</span> </a> </li> <li> <a title="remove row" href="#" id="btmRemove" class="button"> <span>remove row</span> </a> </li> <li> <a title="undo last" href="#" id="btmRollBack" class="button disabled"> <span>undo last</span> </a> </li> <li class="last"> <a title="accept row" href="#" id="btmAccept" class="button disabled"> <span>accept row</span> </a> </li> </ul> </div> <div id="param.list" class="gridclip"> <table id='param.list.tbl' class='grid modela' > <caption>Test Case Summary</caption> <col/><col/><col/> <thead> <tr> <th class='hl center first'> <input class='grid-select-all' type='checkbox' /> <th> <th scope='col'>Row</th> <th scope='col'>Parameter</th> <th scope='col' class='last'>Value</th> </tr> </thead> <tfoot> <tr> <th scope='row'>Total</th> <td colspan='3'>2 parameters as Test Case input</td> </tr> </tfoot> <tbody id='param.list.tbl.body'> <tr class='odd'> <td class='rowcheck center first'> <input value='param1###value1' id='cb1' name='SelectedRows' class='grid-select-row' type='checkbox'/> </td> <td class='id'>1</td> <td>param1</td> <td class='last'>value1</td> </tr> <tr class='even'> <td class='rowcheck center first'> <input value='param2###value2' id='cb1' name='SelectedRows' class='grid-select-row' type='checkbox'/> </td> <td class='id'>2</td> <td>param2</td> <td class='last'>value2</td> </tr> <tr class='odd'> <td class='rowcheck center first' /> <td class='id'><em>new</em></td> <td> <dl class='clsTable'> <dt> <input type='text' id='param' name='param' class='text paramInput' /> </dt> <dd> <span id='paramToggle' /> </dd> <div class='auto-complete' id='paramContainer' /> </dl> </td> <td class='last'> <dl class='clsTable'> <dt> <input type='text' id='value' name='value' class='text valueInput' /> </dt> </dl> </td> </tr> </tbody> </table> </div> </div> </div> <!-- tabcontrol --> </fieldset> <div class="submit-box"> <input type="submit" name="formRun" id="formRun" class="form-save" value="Execute" accesskey="x" title="Run: Press Alt + [Shift] + x" /> <input type="submit" name="formSave" id="formSave" value="Save" accesskey="s" title="Save: Press Alt + [Shift] + s" /> <input type="submit" name="formLoad" id="formLoad" value="Load" accesskey="l" title="Load: Press Alt + [Shift] + l" /> <input type="submit" name="formCancel" id="formCancel" class="form-cancel" value="Cancel" accesskey="c" title="Cancel: Press Alt + [Shift] + c" /> </div> </form> </div> </div> </div> </div> </div> </body> </html> As you can see the following is pretty much a duplicate: <tr class='odd'> <td class='rowcheck center first'> <input value='param1###value1' id='cb1' name='SelectedRows' class='grid-select-row' type='checkbox'/> </td> <td class='id'>1</td> <td>param1</td> <td class='last'>value1</td> </tr> <tr class='even'> <td class='rowcheck center first'> <input value='param2###value2' id='cb1' name='SelectedRows' class='grid-select-row' type='checkbox'/> </td> <td class='id'>2</td> <td>param2</td> <td class='last'>value2</td> </tr> The relevant part of my stuts-config.xml file is: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN" "http://struts.apache.org/dtds/struts-config_1_2.dtd"> <struts-config> <data-sources /> <form-beans> <form-bean name="TestCaseForm" type="com.blahblah.mycoolapp.forms.TestCaseForm" /> </form-beans> <action-mappings> <action path="/pages/SaveTestCase" name="TestCaseForm" type="org.springframework.web.struts.DelegatingActionProxy" scope="request"> </action> </action-mappings> <message-resources parameter="MessageResources" /> </struts-config> I also use spring 2.56 (The relevant part being): <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <bean name="/pages/SaveTestCase" class="com.blahblah.mycoolapp.actions.TestCaseBuilderSaveAction" /> </beans> My Java ActionForm class (from what I had learned off the net) is: package com.blahblah.mycoolapp.forms; import java.util.ArrayList; import java.util.List; import org.apache.struts.action.ActionForm; public class TestCaseForm extends ActionForm { private static final long serialVersionUID = 2352146257739099766L; private String scenario; private String ruleID; private String testCaseName; private List<String> SelectedRows = new ArrayList<String>() ; public String getScenario() { return scenario; } public void setScenario(String scenario) { this.scenario = scenario; } public String getRuleID() { return ruleID; } public void setRuleID(String ruleID) { this.ruleID = ruleID; } public String getTestCaseName() { return testCaseName; } public void setTestCaseName(String testCaseName) { this.testCaseName = testCaseName; } public List<String> getSelectedRows() { return SelectedRows; } public void setSelectedRows(int index, String value) { this.SelectedRows.add(value); } } The question is why do I get an empty SelectedRows in my TestCaseBuilderSave Action? Thanks all who have the patience to read such a long question... and (hopefully) thanks to all you potential saviors :)

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