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• copy files tool with limiter?

  - by pantarhei

  for testing some stuff i need a tool that can copy files from location a to b. but i need to tell the tool how many files it should copy per second. does any one know a tool that can do this?

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• What are some "must have" Mac OS X programs?

  - by Mark

  What 3rd party software is essential on Mac OS X? What would you install immediately once you purchase a Mac? One piece of software per answer please.

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• Is there a USB 3.0 memory stick / thumb drive?

  - by jasondavis

  The new PC I just finished building has USB 3.0 support. I use a USB stick/thumb drive all the time on my PC for stuff, is there an equivalent available anywhere for USB 3.0? Please list one product per post, and provide a link to the manufacturer's product page. Also see the eSATA version of this question.

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• Nginx rewrites - When does one use the break flag (pattern target break)?

  - by anonymous-one

  The nginx wiki states: break - completes processing of current rewrite directives and non-rewrite processing continues within the current location block only. Is this to say that: If the rewrite pattern matches, process the rewrite (rewrite to target) but do not process any of the other rules in the location block, and process all other (cache, proxy, etc) directives in the location block? I am talking about the break flag as per: PATTERN TARGET FLAG Not the "break;" directive. Thanks.

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• PeerApp Scalability

  - by ChaosFreak

  William, In response to a question on P2P caching, you answered "PeerApp can do that but probably doesn't suit the scale you are looking at." PeerApp is the most scalable P2P cache in the world, and can handle hundreds of Gb per second of bandwidth. Their largest deployment in Taiwan handles 120Gbps with no problem. The next largest competitor, OverSi, can barely handle a tenth of that. Where do you get your information that PeerApp "doesn't suit scale"?

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• Web server HW requirements [closed]

  - by Kimo

  Hello, I am trying to search for a book that would teach me how to choose web server HW requirements (hard disk space/technology, ram, internet connection) based on web site statistics (requests per second, etc...), how to scale webservers in case my website is getter higher traffic, etc All I get from the internet is software-related articles. Does anyone know how I can dig in for this kind of information? May be I am just searching using the wrong keywords. Thanks

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• Incorrect units in iotop output

  - by brodie

  iotop is behaving strangely on a opensuse 11.2 server. It all of a sudden started reporting the output in the wrong units. Kilobytes per second are now Terabytes a second, Gigabytes now Petabytes. This server is also having stability issues, so I'm curious as to if the system is reporting things wrong to iotop is related to other issues. Any one else see similar behaviour?

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• Change "From" email address when sending to a specific domain.

  - by RB

  Hi, I would like to set up Exchange so that when a user (e.g. [email protected]) sends an email to somedomain.com Exchange makes the email appear to have come from [email protected]. This would have to be done on a per-domain basis, and invisibly to the user. So all emails come from [email protected], except emails to somedomain.com, which appear to come from [email protected]. If anyone has any ideas I would really appreciate it. Cheers, RB.

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• Is there a way to clone a vitualbox VM and keep the snapshots?

  - by Electrons_Ahoy

  As per questions like this, cloning a VM in VirtualBox is possible, if not all that streightforward. However, everything I've seen indicates that before a VM is cloned, all the snapshots need to be folded back into a single disk image. But, what if I don't want to? Suppose I want to keep my stack of snapshots on the original, and then clone that VM such that the clone also had the same stack of snapshots available? Is that possible?

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• SQL Server 2005: Improving performance for thousands or Insert requests. logout-login time= 120ms.

  - by Rad

  Can somebody shed some lights on how SQL Server 2005 deals with may request issued by a client using ADO.NET 2.0. Below is the shortend output of SQL Trace. I can see that connection pooling is working (I believe there is only one connection being pooled). What is not clear to me is why we have so many sp_reset_connection calls i.e a series of: Audit Login, SQL:BatchStarting, RPC:Starting and Audit Logout for each loop in for loop below. I can see that there is constant switching between tempdb and master database which leads me to conclude that we lost the context when next connection is created by fetching it from the pool based on ConectionString argument. I can see that every 15ms I can get 100-200 login/logout per second (reported at the same time by Profiler). The after 15ms I have again a series fo 100-200 login/logout per second. I need clarification on how this might affect much complex insert queries in production environment. I use Enterprise Library 2006, the code is compiled with VS 2005 and it is a console application that parses a flat file with 10 of thousand of rows grouping parent-child rows, runs on an application server and runs 2 stored procedure on a remote SQL Server 2005 inserting a parent record, retrieves Identity value and using it calls the second stored procedure 1, 2 or multiple times (sometimes several thousands) inserting child records. The child table has close to 10 million records with 5-10 indexes some of them being covering non-clustered. There is a pretty complex Insert trigger that copies inserted detail record to an archive table. All in all I only have 7 inserts per second which means it can take 2-4 hours for 50 thousand records. When I run Profiler on the test server (that is almost equivalent with production server) I can see that there is about 120ms between Audit Logout and Audit Login trace entries which almost give me chance to insert about 8 records. So my question is if there is some way to improve inserting of records since the company loads 100 thousands of records and does daily planning and has SLA to fulfill client request coming as flat file orders and some big files 10 thousands have to be processed(imported quickly). 4 hours to import 60 thousands should be reduced to 30 minutes. I was thinking to use BatchSize of DataAdapter to send multiple stored procedure calls, SQL Bulk inserts to batch multiple inserts from DataReader or DataTable, SSIS fast load. But I don't know how to properly analyze re-indexing and stats population and maybe this has to take some time to finish. What is worse is that the company uses the biggest table for reporting and other online processing and indexes cannot be dropped. I manage transaction manually by setting a field to a value and do an transactional update changing that value to a new value that other applications are using to get committed rows. Please advise how to approach this problem. For now I am trying to have a staging tables with minimal logging in a separate database and no indexes and I will try to do batched (massive) parent child inserts. I believe Production DB has simple recovery model, but it could be full recovery. If DB user that is being used by my .NET console application has bulkadmin role does it mean its bulk inserts are minimally logged. I understand that when a table has clustered and many non-clustered indexes that inserts are still logged for each row. Connection pooling is working, but with many login/logouts. Why? for (int i = 1; i <= 10000; i++){ using (SqlConnection conn = new SqlConnection("server=(local);database=master;integrated security=sspi;")) {conn.Open(); using (SqlCommand cmd = conn.CreateCommand()){ cmd.CommandText = "use tempdb"; cmd.ExecuteNonQuery();}}} SQL Server Profiler trace: Audit Login master 2010-01-13 23:18:45.337 1 - Nonpooled SQL:BatchStarting use tempdb master 2010-01-13 23:18:45.337 RPC:Starting exec sp_reset_conn tempdb 2010-01-13 23:18:45.337 Audit Logout tempdb 2010-01-13 23:18:45.337 2 - Pooled Audit Login -- network protocol master 2010-01-13 23:18:45.383 2 - Pooled SQL:BatchStarting use tempdb master 2010-01-13 23:18:45.383 RPC:Starting exec sp_reset_conn tempdb 2010-01-13 23:18:45.383 Audit Logout tempdb 2010-01-13 23:18:45.383 2 - Pooled Audit Login -- network protocol master 2010-01-13 23:18:45.383 2 - Pooled SQL:BatchStarting use tempdb master 2010-01-13 23:18:45.383 RPC:Starting exec sp_reset_conn tempdb 2010-01-13 23:18:45.383 Audit Logout tempdb 2010-01-13 23:18:45.383 2 - Pooled

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• What is the best Battleship AI?

  - by John Gietzen

  Battleship! Back in 2003, (when I was 17,) I competed in a Battleship AI coding competition. Even though I lost that tournament, I had a lot of fun and learned a lot from it. Now, I would like to resurrect this competition, in the search of the best battleship AI. Here is the framework: Battleship.zip The winner will be awarded +450 reputation! The competition will be held starting on the 17th of November, 2009. No entries or edits later than zero-hour on the 17th will be accepted. (Central Standard Time) Submit your entries early, so you don't miss your opportunity! To keep this OBJECTIVE, please follow the spirit of the competition. Rules of the game: The game is be played on a 10x10 grid. Each competitor will place each of 5 ships (of lengths 2, 3, 3, 4, 5) on their grid. No ships may overlap, but they may be adjacent. The competitors then take turns firing single shots at their opponent. A variation on the game allows firing multiple shots per volley, one for each surviving ship. The opponent will notify the competitor if the shot sinks, hits, or misses. Game play ends when all of the ships of any one player are sunk. Rules of the competition: The spirit of the competition is to find the best Battleship algorithm. Anything that is deemed against the spirit of the competition will be grounds for disqualification. Interfering with an opponent is against the spirit of the competition. Multithreading may be used under the following restrictions: No more than one thread may be running while it is not your turn. (Though, any number of threads may be in a "Suspended" state). No thread may run at a priority other than "Normal". Given the above two restrictions, you will be guaranteed at least 3 dedicated CPU cores during your turn. A limit of 1 second of CPU time per game is allotted to each competitor on the primary thread. Running out of time results in losing the current game. Any unhandled exception will result in losing the current game. Network access and disk access is allowed, but you may find the time restrictions fairly prohibitive. However, a few set-up and tear-down methods have been added to alleviate the time strain. Code should be posted on stack overflow as an answer, or, if too large, linked. Max total size (un-compressed) of an entry is 1 MB. Officially, .Net 2.0 / 3.5 is the only framework requirement. Your entry must implement the IBattleshipOpponent interface. Scoring: Best 51 games out of 101 games is the winner of a match. All competitors will play matched against each other, round-robin style. The best half of the competitors will then play a double-elimination tournament to determine the winner. (Smallest power of two that is greater than or equal to half, actually.) I will be using the TournamentApi framework for the tournament. The results will be posted here. If you submit more than one entry, only your best-scoring entry is eligible for the double-elim. Good luck! Have fun! EDIT 1: Thanks to Freed, who has found an error in the Ship.IsValid function. It has been fixed. Please download the updated version of the framework. EDIT 2: Since there has been significant interest in persisting stats to disk and such, I have added a few non-timed set-up and tear-down events that should provide the required functionality. This is a semi-breaking change. That is to say: the interface has been modified to add functions, but no body is required for them. Please download the updated version of the framework. EDIT 3: Bug Fix 1: GameWon and GameLost were only getting called in the case of a time out. Bug Fix 2: If an engine was timing out every game, the competition would never end. Please download the updated version of the framework. EDIT 4: Results!

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• Using James Server in Eclipse With JavaMail

  - by Jack Sparrow

  Would anyone be able to tell me how I can go about using James server as my server with Java in Eclipse? I'm trying to test the two classes posted below but i get the following error: Exception in thread "main" javax.mail.AuthenticationFailedException: Authentication failed. public class JamesConfigTest { public static void main(String[] args) throws Exception { // CREATE CLIENT INSTANCES MailClient redClient = new MailClient("red", "localhost"); MailClient greenClient = new MailClient("green", "localhost"); MailClient blueClient = new MailClient("blue", "localhost"); // CLEAR EVERYBODY'S INBOX redClient.checkInbox(MailClient.CLEAR_MESSAGES); greenClient.checkInbox(MailClient.CLEAR_MESSAGES); blueClient.checkInbox(MailClient.CLEAR_MESSAGES); Thread.sleep(500); // Let the server catch up // SEND A COUPLE OF MESSAGES TO BLUE (FROM RED AND GREEN) redClient.sendMessage( "blue@localhost", "Testing blue from red", "This is a test message"); greenClient.sendMessage( "blue@localhost", "Testing blue from green", "This is a test message"); Thread.sleep(500); // Let the server catch up // LIST MESSAGES FOR BLUE (EXPECT MESSAGES FROM RED AND GREEN) blueClient.checkInbox(MailClient.SHOW_AND_CLEAR); } } import java.io.*; import java.util.*; import javax.mail.*; import javax.mail.internet.*; public class MailClient extends Authenticator { public static final int SHOW_MESSAGES = 1; public static final int CLEAR_MESSAGES = 2; public static final int SHOW_AND_CLEAR = SHOW_MESSAGES + CLEAR_MESSAGES; protected String from; protected Session session; protected PasswordAuthentication authentication; public MailClient(String user, String host) { this(user, host, false); } public MailClient(String user, String host, boolean debug) { from = user + '@' + host; authentication = new PasswordAuthentication(user, user); Properties props = new Properties(); props.put("mail.user", user); props.put("mail.host", host); props.put("mail.debug", debug ? "true" : "false"); props.put("mail.store.protocol", "pop3"); props.put("mail.transport.protocol", "smtp"); session = Session.getInstance(props, this); } public PasswordAuthentication getPasswordAuthentication() { return authentication; } public void sendMessage( String to, String subject, String content) throws MessagingException { System.out.println("SENDING message from " + from + " to " + to); System.out.println(); MimeMessage msg = new MimeMessage(session); msg.addRecipients(Message.RecipientType.TO, to); msg.setSubject(subject); msg.setText(content); Transport.send(msg); } public void checkInbox(int mode) throws MessagingException, IOException { if (mode == 0) return; boolean show = (mode & SHOW_MESSAGES) > 0; boolean clear = (mode & CLEAR_MESSAGES) > 0; String action = (show ? "Show" : "") + (show && clear ? " and " : "") + (clear ? "Clear" : ""); System.out.println(action + " INBOX for " + from); Store store = session.getStore(); store.connect(); Folder root = store.getDefaultFolder(); Folder inbox = root.getFolder("inbox"); inbox.open(Folder.READ_WRITE); Message[] msgs = inbox.getMessages(); if (msgs.length == 0 && show) { System.out.println("No messages in inbox"); } for (int i = 0; i < msgs.length; i++) { MimeMessage msg = (MimeMessage)msgs[i]; if (show) { System.out.println(" From: " + msg.getFrom()[0]); System.out.println(" Subject: " + msg.getSubject()); System.out.println(" Content: " + msg.getContent()); } if (clear) { msg.setFlag(Flags.Flag.DELETED, true); } } inbox.close(true); store.close(); System.out.println(); } }

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• What are good design practices when working with Entity Framework

  - by AD

  This will apply mostly for an asp.net application where the data is not accessed via soa. Meaning that you get access to the objects loaded from the framework, not Transfer Objects, although some recommendation still apply. This is a community post, so please add to it as you see fit. Applies to: Entity Framework 1.0 shipped with Visual Studio 2008 sp1. Why pick EF in the first place? Considering it is a young technology with plenty of problems (see below), it may be a hard sell to get on the EF bandwagon for your project. However, it is the technology Microsoft is pushing (at the expense of Linq2Sql, which is a subset of EF). In addition, you may not be satisfied with NHibernate or other solutions out there. Whatever the reasons, there are people out there (including me) working with EF and life is not bad.make you think. EF and inheritance The first big subject is inheritance. EF does support mapping for inherited classes that are persisted in 2 ways: table per class and table the hierarchy. The modeling is easy and there are no programming issues with that part. (The following applies to table per class model as I don't have experience with table per hierarchy, which is, anyway, limited.) The real problem comes when you are trying to run queries that include one or many objects that are part of an inheritance tree: the generated sql is incredibly awful, takes a long time to get parsed by the EF and takes a long time to execute as well. This is a real show stopper. Enough that EF should probably not be used with inheritance or as little as possible. Here is an example of how bad it was. My EF model had ~30 classes, ~10 of which were part of an inheritance tree. On running a query to get one item from the Base class, something as simple as Base.Get(id), the generated SQL was over 50,000 characters. Then when you are trying to return some Associations, it degenerates even more, going as far as throwing SQL exceptions about not being able to query more than 256 tables at once. Ok, this is bad, EF concept is to allow you to create your object structure without (or with as little as possible) consideration on the actual database implementation of your table. It completely fails at this. So, recommendations? Avoid inheritance if you can, the performance will be so much better. Use it sparingly where you have to. In my opinion, this makes EF a glorified sql-generation tool for querying, but there are still advantages to using it. And ways to implement mechanism that are similar to inheritance. Bypassing inheritance with Interfaces First thing to know with trying to get some kind of inheritance going with EF is that you cannot assign a non-EF-modeled class a base class. Don't even try it, it will get overwritten by the modeler. So what to do? You can use interfaces to enforce that classes implement some functionality. For example here is a IEntity interface that allow you to define Associations between EF entities where you don't know at design time what the type of the entity would be. public enum EntityTypes{ Unknown = -1, Dog = 0, Cat } public interface IEntity { int EntityID { get; } string Name { get; } Type EntityType { get; } } public partial class Dog : IEntity { // implement EntityID and Name which could actually be fields // from your EF model Type EntityType{ get{ return EntityTypes.Dog; } } } Using this IEntity, you can then work with undefined associations in other classes // lets take a class that you defined in your model. // that class has a mapping to the columns: PetID, PetType public partial class Person { public IEntity GetPet() { return IEntityController.Get(PetID,PetType); } } which makes use of some extension functions: public class IEntityController { static public IEntity Get(int id, EntityTypes type) { switch (type) { case EntityTypes.Dog: return Dog.Get(id); case EntityTypes.Cat: return Cat.Get(id); default: throw new Exception("Invalid EntityType"); } } } Not as neat as having plain inheritance, particularly considering you have to store the PetType in an extra database field, but considering the performance gains, I would not look back. It also cannot model one-to-many, many-to-many relationship, but with creative uses of 'Union' it could be made to work. Finally, it creates the side effet of loading data in a property/function of the object, which you need to be careful about. Using a clear naming convention like GetXYZ() helps in that regards. Compiled Queries Entity Framework performance is not as good as direct database access with ADO (obviously) or Linq2SQL. There are ways to improve it however, one of which is compiling your queries. The performance of a compiled query is similar to Linq2Sql. What is a compiled query? It is simply a query for which you tell the framework to keep the parsed tree in memory so it doesn't need to be regenerated the next time you run it. So the next run, you will save the time it takes to parse the tree. Do not discount that as it is a very costly operation that gets even worse with more complex queries. There are 2 ways to compile a query: creating an ObjectQuery with EntitySQL and using CompiledQuery.Compile() function. (Note that by using an EntityDataSource in your page, you will in fact be using ObjectQuery with EntitySQL, so that gets compiled and cached). An aside here in case you don't know what EntitySQL is. It is a string-based way of writing queries against the EF. Here is an example: "select value dog from Entities.DogSet as dog where dog.ID = @ID". The syntax is pretty similar to SQL syntax. You can also do pretty complex object manipulation, which is well explained [here][1]. Ok, so here is how to do it using ObjectQuery< string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); The first time you run this query, the framework will generate the expression tree and keep it in memory. So the next time it gets executed, you will save on that costly step. In that example EnablePlanCaching = true, which is unnecessary since that is the default option. The other way to compile a query for later use is the CompiledQuery.Compile method. This uses a delegate: static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => ctx.DogSet.FirstOrDefault(it => it.ID == id)); or using linq static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet where dog.ID == id select dog).FirstOrDefault()); to call the query: query_GetDog.Invoke( YourContext, id ); The advantage of CompiledQuery is that the syntax of your query is checked at compile time, where as EntitySQL is not. However, there are other consideration... Includes Lets say you want to have the data for the dog owner to be returned by the query to avoid making 2 calls to the database. Easy to do, right? EntitySQL string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)).Include("Owner"); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); CompiledQuery static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet.Include("Owner") where dog.ID == id select dog).FirstOrDefault()); Now, what if you want to have the Include parametrized? What I mean is that you want to have a single Get() function that is called from different pages that care about different relationships for the dog. One cares about the Owner, another about his FavoriteFood, another about his FavotireToy and so on. Basicly, you want to tell the query which associations to load. It is easy to do with EntitySQL public Dog Get(int id, string include) { string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)) .IncludeMany(include); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); } The include simply uses the passed string. Easy enough. Note that it is possible to improve on the Include(string) function (that accepts only a single path) with an IncludeMany(string) that will let you pass a string of comma-separated associations to load. Look further in the extension section for this function. If we try to do it with CompiledQuery however, we run into numerous problems: The obvious static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.Include(include) where dog.ID == id select dog).FirstOrDefault()); will choke when called with: query_GetDog.Invoke( YourContext, id, "Owner,FavoriteFood" ); Because, as mentionned above, Include() only wants to see a single path in the string and here we are giving it 2: "Owner" and "FavoriteFood" (which is not to be confused with "Owner.FavoriteFood"!). Then, let's use IncludeMany(), which is an extension function static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.IncludeMany(include) where dog.ID == id select dog).FirstOrDefault()); Wrong again, this time it is because the EF cannot parse IncludeMany because it is not part of the functions that is recognizes: it is an extension. Ok, so you want to pass an arbitrary number of paths to your function and Includes() only takes a single one. What to do? You could decide that you will never ever need more than, say 20 Includes, and pass each separated strings in a struct to CompiledQuery. But now the query looks like this: from dog in ctx.DogSet.Include(include1).Include(include2).Include(include3) .Include(include4).Include(include5).Include(include6) .[...].Include(include19).Include(include20) where dog.ID == id select dog which is awful as well. Ok, then, but wait a minute. Can't we return an ObjectQuery< with CompiledQuery? Then set the includes on that? Well, that what I would have thought so as well: static readonly Func<Entities, int, ObjectQuery<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, ObjectQuery<Dog>>((ctx, id) => (ObjectQuery<Dog>)(from dog in ctx.DogSet where dog.ID == id select dog)); public Dog GetDog( int id, string include ) { ObjectQuery<Dog> oQuery = query_GetDog(id); oQuery = oQuery.IncludeMany(include); return oQuery.FirstOrDefault; } That should have worked, except that when you call IncludeMany (or Include, Where, OrderBy...) you invalidate the cached compiled query because it is an entirely new one now! So, the expression tree needs to be reparsed and you get that performance hit again. So what is the solution? You simply cannot use CompiledQueries with parametrized Includes. Use EntitySQL instead. This doesn't mean that there aren't uses for CompiledQueries. It is great for localized queries that will always be called in the same context. Ideally CompiledQuery should always be used because the syntax is checked at compile time, but due to limitation, that's not possible. An example of use would be: you may want to have a page that queries which two dogs have the same favorite food, which is a bit narrow for a BusinessLayer function, so you put it in your page and know exactly what type of includes are required. Passing more than 3 parameters to a CompiledQuery Func is limited to 5 parameters, of which the last one is the return type and the first one is your Entities object from the model. So that leaves you with 3 parameters. A pitance, but it can be improved on very easily. public struct MyParams { public string param1; public int param2; public DateTime param3; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where dog.Age == myParams.param2 && dog.Name == myParams.param1 and dog.BirthDate > myParams.param3 select dog); public List<Dog> GetSomeDogs( int age, string Name, DateTime birthDate ) { MyParams myParams = new MyParams(); myParams.param1 = name; myParams.param2 = age; myParams.param3 = birthDate; return query_GetDog(YourContext,myParams).ToList(); } Return Types (this does not apply to EntitySQL queries as they aren't compiled at the same time during execution as the CompiledQuery method) Working with Linq, you usually don't force the execution of the query until the very last moment, in case some other functions downstream wants to change the query in some way: static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public IEnumerable<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name); } public void DataBindStuff() { IEnumerable<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } What is going to happen here? By still playing with the original ObjectQuery (that is the actual return type of the Linq statement, which implements IEnumerable), it will invalidate the compiled query and be force to re-parse. So, the rule of thumb is to return a List< of objects instead. static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public List<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name).ToList(); //<== change here } public void DataBindStuff() { List<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } When you call ToList(), the query gets executed as per the compiled query and then, later, the OrderBy is executed against the objects in memory. It may be a little bit slower, but I'm not even sure. One sure thing is that you have no worries about mis-handling the ObjectQuery and invalidating the compiled query plan. Once again, that is not a blanket statement. ToList() is a defensive programming trick, but if you have a valid reason not to use ToList(), go ahead. There are many cases in which you would want to refine the query before executing it. Performance What is the performance impact of compiling a query? It can actually be fairly large. A rule of thumb is that compiling and caching the query for reuse takes at least double the time of simply executing it without caching. For complex queries (read inherirante), I have seen upwards to 10 seconds. So, the first time a pre-compiled query gets called, you get a performance hit. After that first hit, performance is noticeably better than the same non-pre-compiled query. Practically the same as Linq2Sql When you load a page with pre-compiled queries the first time you will get a hit. It will load in maybe 5-15 seconds (obviously more than one pre-compiled queries will end up being called), while subsequent loads will take less than 300ms. Dramatic difference, and it is up to you to decide if it is ok for your first user to take a hit or you want a script to call your pages to force a compilation of the queries. Can this query be cached? { Dog dog = from dog in YourContext.DogSet where dog.ID == id select dog; } No, ad-hoc Linq queries are not cached and you will incur the cost of generating the tree every single time you call it. Parametrized Queries Most search capabilities involve heavily parametrized queries. There are even libraries available that will let you build a parametrized query out of lamba expressions. The problem is that you cannot use pre-compiled queries with those. One way around that is to map out all the possible criteria in the query and flag which one you want to use: public struct MyParams { public string name; public bool checkName; public int age; public bool checkAge; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where (myParams.checkAge == true && dog.Age == myParams.age) && (myParams.checkName == true && dog.Name == myParams.name ) select dog); protected List<Dog> GetSomeDogs() { MyParams myParams = new MyParams(); myParams.name = "Bud"; myParams.checkName = true; myParams.age = 0; myParams.checkAge = false; return query_GetDog(YourContext,myParams).ToList(); } The advantage here is that you get all the benifits of a pre-compiled quert. The disadvantages are that you most likely will end up with a where clause that is pretty difficult to maintain, that you will incur a bigger penalty for pre-compiling the query and that each query you run is not as efficient as it could be (particularly with joins thrown in). Another way is to build an EntitySQL query piece by piece, like we all did with SQL. protected List<Dod> GetSomeDogs( string name, int age) { string query = "select value dog from Entities.DogSet where 1 = 1 "; if( !String.IsNullOrEmpty(name) ) query = query + " and dog.Name == @Name "; if( age > 0 ) query = query + " and dog.Age == @Age "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); if( !String.IsNullOrEmpty(name) ) oQuery.Parameters.Add( new ObjectParameter( "Name", name ) ); if( age > 0 ) oQuery.Parameters.Add( new ObjectParameter( "Age", age ) ); return oQuery.ToList(); } Here the problems are: - there is no syntax checking during compilation - each different combination of parameters generate a different query which will need to be pre-compiled when it is first run. In this case, there are only 4 different possible queries (no params, age-only, name-only and both params), but you can see that there can be way more with a normal world search. - Noone likes to concatenate strings! Another option is to query a large subset of the data and then narrow it down in memory. This is particularly useful if you are working with a definite subset of the data, like all the dogs in a city. You know there are a lot but you also know there aren't that many... so your CityDog search page can load all the dogs for the city in memory, which is a single pre-compiled query and then refine the results protected List<Dod> GetSomeDogs( string name, int age, string city) { string query = "select value dog from Entities.DogSet where dog.Owner.Address.City == @City "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); oQuery.Parameters.Add( new ObjectParameter( "City", city ) ); List<Dog> dogs = oQuery.ToList(); if( !String.IsNullOrEmpty(name) ) dogs = dogs.Where( it => it.Name == name ); if( age > 0 ) dogs = dogs.Where( it => it.Age == age ); return dogs; } It is particularly useful when you start displaying all the data then allow for filtering. Problems: - Could lead to serious data transfer if you are not careful about your subset. - You can only filter on the data that you returned. It means that if you don't return the Dog.Owner association, you will not be able to filter on the Dog.Owner.Name So what is the best solution? There isn't any. You need to pick the solution that works best for you and your problem: - Use lambda-based query building when you don't care about pre-compiling your queries. - Use fully-defined pre-compiled Linq query when your object structure is not too complex. - Use EntitySQL/string concatenation when the structure could be complex and when the possible number of different resulting queries are small (which means fewer pre-compilation hits). - Use in-memory filtering when you are working with a smallish subset of the data or when you had to fetch all of the data on the data at first anyway (if the performance is fine with all the data, then filtering in memory will not cause any time to be spent in the db). Singleton access The best way to deal with your context and entities accross all your pages is to use the singleton pattern: public sealed class YourContext { private const string instanceKey = "On3GoModelKey"; YourContext(){} public static YourEntities Instance { get { HttpContext context = HttpContext.Current; if( context == null ) return Nested.instance; if (context.Items[instanceKey] == null) { On3GoEntities entity = new On3GoEntities(); context.Items[instanceKey] = entity; } return (YourEntities)context.Items[instanceKey]; } } class Nested { // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit static Nested() { } internal static readonly YourEntities instance = new YourEntities(); } } NoTracking, is it worth it? When executing a query, you can tell the framework to track the objects it will return or not. What does it mean? With tracking enabled (the default option), the framework will track what is going on with the object (has it been modified? Created? Deleted?) and will also link objects together, when further queries are made from the database, which is what is of interest here. For example, lets assume that Dog with ID == 2 has an owner which ID == 10. Dog dog = (from dog in YourContext.DogSet where dog.ID == 2 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Person owner = (from o in YourContext.PersonSet where o.ID == 10 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == true; If we were to do the same with no tracking, the result would be different. ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog = oDogQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>) (from o in YourContext.PersonSet where o.ID == 10 select o); oPersonQuery.MergeOption = MergeOption.NoTracking; Owner owner = oPersonQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Tracking is very useful and in a perfect world without performance issue, it would always be on. But in this world, there is a price for it, in terms of performance. So, should you use NoTracking to speed things up? It depends on what you are planning to use the data for. Is there any chance that the data your query with NoTracking can be used to make update/insert/delete in the database? If so, don't use NoTracking because associations are not tracked and will causes exceptions to be thrown. In a page where there are absolutly no updates to the database, you can use NoTracking. Mixing tracking and NoTracking is possible, but it requires you to be extra careful with updates/inserts/deletes. The problem is that if you mix then you risk having the framework trying to Attach() a NoTracking object to the context where another copy of the same object exist with tracking on. Basicly, what I am saying is that Dog dog1 = (from dog in YourContext.DogSet where dog.ID == 2).FirstOrDefault(); ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog2 = oDogQuery.FirstOrDefault(); dog1 and dog2 are 2 different objects, one tracked and one not. Using the detached object in an update/insert will force an Attach() that will say "Wait a minute, I do already have an object here with the same database key. Fail". And when you Attach() one object, all of its hierarchy gets attached as well, causing problems everywhere. Be extra careful. How much faster is it with NoTracking It depends on the queries. Some are much more succeptible to tracking than other. I don't have a fast an easy rule for it, but it helps. So I should use NoTracking everywhere then? Not exactly. There are some advantages to tracking object. The first one is that the object is cached, so subsequent call for that object will not hit the database. That cache is only valid for the lifetime of the YourEntities object, which, if you use the singleton code above, is the same as the page lifetime. One page request == one YourEntity object. So for multiple calls for the same object, it will load only once per page request. (Other caching mechanism could extend that). What happens when you are using NoTracking and try to load the same object multiple times? The database will be queried each time, so there is an impact there. How often do/should you call for the same object during a single page request? As little as possible of course, but it does happens. Also remember the piece above about having the associations connected automatically for your? You don't have that with NoTracking, so if you load your data in multiple batches, you will not have a link to between them: ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>)(from dog in YourContext.DogSet select dog); oDogQuery.MergeOption = MergeOption.NoTracking; List<Dog> dogs = oDogQuery.ToList(); ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>)(from o in YourContext.PersonSet select o); oPersonQuery.MergeOption = MergeOption.NoTracking; List<Person> owners = oPersonQuery.ToList(); In this case, no dog will have its .Owner property set. Some things to keep in mind when you are trying to optimize the performance. No lazy loading, what am I to do? This can be seen as a blessing in disguise. Of course it is annoying to load everything manually. However, it decreases the number of calls to the db and forces you to think about when you should load data. The more you can load in one database call the better. That was always true, but it is enforced now with this 'feature' of EF. Of course, you can call if( !ObjectReference.IsLoaded ) ObjectReference.Load(); if you want to, but a better practice is to force the framework to load the objects you know you will need in one shot. This is where the discussion about parametrized Includes begins to make sense. Lets say you have you Dog object public class Dog { public Dog Get(int id) { return YourContext.DogSet.FirstOrDefault(it => it.ID == id ); } } This is the type of function you work with all the time. It gets called from all over the place and once you have that Dog object, you will do very different things to it in different functions. First, it should be pre-compiled, because you will call that very often. Second, each different pages will want to have access to a different subset of the Dog data. Some will want the Owner, some the FavoriteToy, etc. Of course, you could call Load() for each reference you need anytime you need one. But that will generate a call to the database each time. Bad idea. So instead, each page will ask for the data it wants to see when it first request for the Dog object: static public Dog Get(int id) { return GetDog(entity,"");} static public Dog Get(int id, string includePath) { string query = "select value o " + " from YourEntities.DogSet as o " +

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• running multi threads in Java

  - by owca

  My task is to simulate activity of couple of persons. Each of them has few activities to perform in some random time: fast (0-5s), medium(5-10s), slow(10-20s) and very slow(20-30s). Each person performs its task independently in the same time. At the beginning of new task I should print it's random time, start the task and then after time passes show next task's time and start it. I've written run() function that counts time, but now it looks like threads are done one after another and not in the same time or maybe they're just printed in this way. public class People{ public static void main(String[] args){ Task tasksA[]={new Task("washing","fast"), new Task("reading","slow"), new Task("shopping","medium")}; Task tasksM[]={new Task("sleeping zzzzzzzzzz","very slow"), new Task("learning","slow"), new Task(" :** ","slow"), new Task("passing an exam","slow") }; Task tasksJ[]={new Task("listening music","medium"), new Task("doing nothing","slow"), new Task("walking","medium") }; BusyPerson friends[]={ new BusyPerson("Alice",tasksA), new BusyPerson("Mark",tasksM), new BusyPerson("John",tasksJ)}; System.out.println("STARTING....................."); for(BusyPerson f: friends) (new Thread(f)).start(); System.out.println("DONE........................."); } } class Task { private String task; private int time; private Task[]tasks; public Task(String t, String s){ task = t; Speed speed = new Speed(); time = speed.getSpeed(s); } public Task(Task[]tab){ Task[]table=new Task[tab.length]; for(int i=0; i < tab.length; i++){ table[i] = tab[i]; } this.tasks = table; } } class Speed { private static String[]hows = {"fast","medium","slow","very slow"}; private static int[]maxs = {5000, 10000, 20000, 30000}; public Speed(){ } public static int getSpeed( String speedString){ String s = speedString; int up_limit=0; int down_limit=0; int time=0; //get limits of time for(int i=0; i<hows.length; i++){ if(s.equals(hows[i])){ up_limit = maxs[i]; if(i>0){ down_limit = maxs[i-1]; } else{ down_limit = 0; } } } //get random time within the limits Random rand = new Random(); time = rand.nextInt(up_limit) + down_limit; return time; } } class BusyPerson implements Runnable { private String name; private Task[] person_tasks; private BusyPerson[]persons; public BusyPerson(String s, Task[]t){ name = s; person_tasks = t; } public BusyPerson(BusyPerson[]tab){ BusyPerson[]table=new BusyPerson[tab.length]; for(int i=0; i < tab.length; i++){ table[i] = tab[i]; } this.persons = table; } public void run() { int time = 0; double t1=0; for(Task t: person_tasks){ t1 = (double)t.time/1000; System.out.println(name+" is... "+t.task+" "+t.speed+ " ("+t1+" sec)"); while (time == t.time) { try { Thread.sleep(10); } catch(InterruptedException exc) { System.out.println("End of thread."); return; } time = time + 100; } } } } And my output : STARTING..................... DONE......................... Mark is... sleeping zzzzzzzzzz very slow (36.715 sec) Mark is... learning slow (10.117 sec) Mark is... :** slow (29.543 sec) Mark is... passing an exam slow (23.429 sec) Alice is... washing fast (1.209 sec) Alice is... reading slow (23.21 sec) Alice is... shopping medium (11.237 sec) John is... listening music medium (8.263 sec) John is... doing nothing slow (13.576 sec) John is... walking medium (11.322 sec) Whilst it should be like this : STARTING..................... DONE......................... John is... listening music medium (7.05 sec) Alice is... washing fast (3.268 sec) Mark is... sleeping zzzzzzzzzz very slow (23.71 sec) Alice is... reading slow (15.516 sec) John is... doing nothing slow (13.692 sec) Alice is... shopping medium (8.371 sec) Mark is... learning slow (13.904 sec) John is... walking medium (5.172 sec) Mark is... :** slow (12.322 sec) Mark is... passing an exam very slow (27.1 sec)

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• applet does not load

  - by jcp

  We have a legacy program that was ported from Java 1.3 to Java 1.5. This application involves applets which worked fine before. After porting however, the applet would not load. However there are no errors or exceptions. The app would just try to load it forever. We tried to run it with Java 1.6 and poof! No problems whatsoever. Isn't Java 6 backwards compatible? So how come it would run in that version and not in 1.5? ==== Java Console log for Java 1.5.0_19 basic: Registered modality listener basic: Registered modality listener basic: Registered modality listener liveconnect: Invoking JS method: document liveconnect: Invoking JS method: document liveconnect: Invoking JS method: document liveconnect: Invoking JS method: URL liveconnect: Invoking JS method: URL liveconnect: Invoking JS method: URL basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=1 basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=2 basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=3 basic: Added progress listener: sun.plugin.util.GrayBoxPainter@b0bad7 basic: Loading applet ... basic: Initializing applet ... basic: Starting applet ... basic: Added progress listener: sun.plugin.util.GrayBoxPainter@ba9340 basic: Added progress listener: sun.plugin.util.GrayBoxPainter@1198891 basic: Loading applet ... basic: Initializing applet ... basic: Starting applet ... basic: Loading applet ... basic: Initializing applet ... basic: Starting applet ... basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=4 basic: Releasing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=3 basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=4 basic: Releasing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=3 basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=4 basic: Releasing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=3 network: Connecting <something>.jar with proxy=HTTP @ proxy/<ip address> basic: Loading <something>.jar from cache basic: No certificate info, this is unsigned JAR file. Left START init() Left END init() Right START init() Control start() Waiting for Left Panel to load... Right START start() network: Connecting socket://<ip address>:14444 with proxy=DIRECT Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... my HostName : <ip address> Thread-19 Check : Thread-19 Check : Monitor : run : start Thread-20 Monitor : Monitor: run() start Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... the last message goes on forever... and now with the working version: ==== Java Console log for Java 1.6.0_15 basic: Added progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@1b000e7 basic: Added progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@12611a7 basic: Added progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@1807ca8 network: CleanupThread used 6 us network: CleanupThread used 5 us network: CleanupThread used 6 us cache: Skip blacklist check as cached value is ok. network: Cache entry found [url: <something>.jar, version: null] network: Connecting <something>.jar with proxy=HTTP @ proxy/<ip address> network: ResponseCode for <something>.jar : 304 network: Encoding for <something>.jar : null network: Disconnect connection to <something>.jar Reading certificates from 11 <something>.jar | <something>.idx network: No certificate info for unsigned JAR file: <something>.jar basic: Applet loaded. basic: Applet loaded. basic: Applet resized and added to parent container basic: Applet resized and added to parent container basic: PERF: AppletExecutionRunnable - applet.init() BEGIN ; jvmLaunch dt 330275 us, pluginInit dt 27768955 us, TotalTime: 28099230 us Right START init() basic: PERF: AppletExecutionRunnable - applet.init() BEGIN ; jvmLaunch dt 330275 us, pluginInit dt 27770563 us, TotalTime: 28100838 us Left START init() basic: Applet loaded. basic: Applet resized and added to parent container basic: PERF: AppletExecutionRunnable - applet.init() BEGIN ; jvmLaunch dt 330275 us, pluginInit dt 27779332 us, TotalTime: 28109607 us Left END init() basic: Applet initialized basic: Removed progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@12611a7 basic: Applet made visible And that's it. Still haven't figured out why it works with java6 and not java5. @valli: the object tag was used, not applet @thorbjorn: i tried that already... it just keeps saying loading applet... @aaron: how can i know what exception it is, if there really is one? and yes we have considered that its a java bug but i still havent found what that bug is. i have to submit a report tomorrow and i've scoured the net but came up with nothing as of yet... @all: thank you for your replies

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• Has glassfish 2.1.1 a bug handling http request and handle them twice?

  - by marabol

  I'm using glassfish 2.1.1. I've watched a mysterious http/webservice-call handling. It seams an http request is handled by two different threads. After http basic authentication the first thread is faster. Persisting some data end, but writing response fails in glassfish internal. The second thread fails, because it tries to persist identical data and there are (unique) constrain failures. The response (the failure) of second thread was delivered to client. I don't won't discuss the behavior with the unique constrain failure. I've improve the webservice, so it can handle this better, because it could be happen anytime, that the client send the ws call a second time. But I think, glassfish 2.1.1 has an bug handling http request. Is there any known issue? Have I done an mistake? [#|2010-03-22T10:40:54.150+0000|INFO|sun-appserver2.1|javax.enterprise.system.core|_ThreadID=10;_ThreadName=main;|Starting Sun GlassFish Enterprise Server v2.1.1 ((v2.1 Patch06)(9.1_02 Patch12)) (build b31g-fcs) ...|#] ... [#|2010-03-22T11:18:44.220+0000|FINE|sun-appserver2.1|mypackage.module.security.auth.realm.YaJdbcRealm|_ThreadID=26;_ThreadName=httpSSLWorkerThread-8080-1;ClassName=mypackage.module.security.auth.realm.YaJdbcRealm;MethodName=authenticate;_RequestID=4d8f23e9-5106-4d64-b865-1638d7075bde;|JDBC authenticate successful for: 8002 groups:[roleUser]|#] [#|2010-03-22T11:18:44.220+0000|FINE|sun-appserver2.1|mypackage.module.security.auth.login.YaJdbcLoginModule|_ThreadID=26;_ThreadName=httpSSLWorkerThread-8080-1;ClassName=mypackage.module.security.auth.login.YaJdbcLoginModule;MethodName=authenticate;_RequestID=4d8f23e9-5106-4d64-b865-1638d7075bde;|JDBC login succeeded for: 8002 groups:[roleUser]|#] [#|2010-03-22T11:18:44.220+0000|FINE|sun-appserver2.1|mypackage.module.security.auth.realm.YaJdbcRealm|_ThreadID=39;_ThreadName=httpSSLWorkerThread-8080-2;ClassName=mypackage.module.security.auth.realm.YaJdbcRealm;MethodName=authenticate;_RequestID=4ca7e3e5-5ab7-41ec-b3c9-d9260b1164c9;|JDBC authenticate successful for: 8002 groups:[roleUser]|#] [#|2010-03-22T11:18:44.220+0000|FINE|sun-appserver2.1|mypackage.module.security.auth.login.YaJdbcLoginModule|_ThreadID=39;_ThreadName=httpSSLWorkerThread-8080-2;ClassName=mypackage.module.security.auth.login.YaJdbcLoginModule;MethodName=authenticate;_RequestID=4ca7e3e5-5ab7-41ec-b3c9-d9260b1164c9;|JDBC login succeeded for: 8002 groups:[roleUser]|#] [#|2010-03-22T11:18:44.220+0000|FINE|sun-appserver2.1|mypackage.MyWebService|_ThreadID=26;_ThreadName=httpSSLWorkerThread-8080-1;ClassName=mypackage.MyWebService;MethodName=enqueue;_RequestID=4d8f23e9-5106-4d64-b865-1638d7075bde;|Received WebService call to enqueue() from client 59|#] [#|2010-03-22T11:18:44.220+0000|FINE|sun-appserver2.1|mypackage.MyWebService|_ThreadID=39;_ThreadName=httpSSLWorkerThread-8080-2;ClassName=mypackage.MyWebService;MethodName=enqueue;_RequestID=4ca7e3e5-5ab7-41ec-b3c9-d9260b1164c9;|Received WebService call to enqueue() from client 59|#] ... [#|2010-03-22T11:18:44.267+0000|FINE|sun-appserver2.1|mypackage.MyWebService|_ThreadID=26;_ThreadName=httpSSLWorkerThread-8080-1;ClassName=mypackage.MyWebService;MethodName=enqueue;_RequestID=4d8f23e9-5106-4d64-b865-1638d7075bde;|Successfully finished WebService call to enqueue() from client 59|#] [#|2010-03-22T11:18:44.329+0000|WARNING|sun-appserver2.1|javax.enterprise.system.container.ejb|_ThreadID=26;_ThreadName=httpSSLWorkerThread-8080-1;_RequestID=4d8f23e9-5106-4d64-b865-1638d7075bde;|invocation error on ejb endpoint MyWebService at /MyWebserviceService/MyWebservice : com.sun.xml.stream.XMLStreamException2 javax.xml.ws.WebServiceException: com.sun.xml.stream.XMLStreamException2 at com.sun.xml.ws.encoding.StreamSOAPCodec.encode(StreamSOAPCodec.java:111) at com.sun.xml.ws.encoding.SOAPBindingCodec.encode(SOAPBindingCodec.java:281) at com.sun.xml.ws.transport.http.HttpAdapter.encodePacket(HttpAdapter.java:320) at com.sun.xml.ws.transport.http.HttpAdapter.access$100(HttpAdapter.java:93) at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:454) at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:244) at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:135) at com.sun.enterprise.webservice.Ejb3MessageDispatcher.handlePost(Ejb3MessageDispatcher.java:113) at com.sun.enterprise.webservice.Ejb3MessageDispatcher.invoke(Ejb3MessageDispatcher.java:87) at com.sun.enterprise.webservice.EjbWebServiceServlet.dispatchToEjbEndpoint(EjbWebServiceServlet.java:231) at com.sun.enterprise.webservice.EjbWebServiceServlet.service(EjbWebServiceServlet.java:157) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at com.sun.enterprise.web.AdHocContextValve.invoke(AdHocContextValve.java:114) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:587) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:87) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:222) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:587) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1093) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:166) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:587) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1093) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:291) at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.invokeAdapter(DefaultProcessorTask.java:666) at com.sun.enterprise.web.connector.grizzly.comet.CometEngine.executeServlet(CometEngine.java:616) at com.sun.enterprise.web.connector.grizzly.comet.CometEngine.handle(CometEngine.java:362) at com.sun.enterprise.web.connector.grizzly.comet.CometAsyncFilter.doFilter(CometAsyncFilter.java:84) at com.sun.enterprise.web.connector.grizzly.async.DefaultAsyncExecutor.invokeFilters(DefaultAsyncExecutor.java:189) at com.sun.enterprise.web.connector.grizzly.async.DefaultAsyncExecutor.interrupt(DefaultAsyncExecutor.java:164) at com.sun.enterprise.web.connector.grizzly.async.AsyncProcessorTask.doTask(AsyncProcessorTask.java:92) at com.sun.enterprise.web.connector.grizzly.TaskBase.run(TaskBase.java:264) at com.sun.enterprise.web.connector.grizzly.ssl.SSLWorkerThread.run(SSLWorkerThread.java:106) Caused by: com.sun.xml.stream.XMLStreamException2 at com.sun.xml.stream.writers.XMLStreamWriterImpl.flush(XMLStreamWriterImpl.java:416) at com.sun.xml.ws.encoding.StreamSOAPCodec.encode(StreamSOAPCodec.java:109) ... 36 more Caused by: ClientAbortException: java.nio.channels.ClosedChannelException at org.apache.coyote.tomcat5.OutputBuffer.doFlush(OutputBuffer.java:385) at org.apache.coyote.tomcat5.OutputBuffer.flush(OutputBuffer.java:351) at org.apache.coyote.tomcat5.CoyoteOutputStream.flush(CoyoteOutputStream.java:176) at com.sun.xml.stream.writers.UTF8OutputStreamWriter.flush(UTF8OutputStreamWriter.java:153) at com.sun.xml.stream.writers.XMLStreamWriterImpl.flush(XMLStreamWriterImpl.java:414) ... 37 more Caused by: java.nio.channels.ClosedChannelException at sun.nio.ch.SocketChannelImpl.ensureWriteOpen(SocketChannelImpl.java:126) at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:324) at com.sun.enterprise.web.connector.grizzly.OutputWriter.flushChannel(OutputWriter.java:91) at com.sun.enterprise.web.connector.grizzly.OutputWriter.flushChannel(OutputWriter.java:66) at com.sun.enterprise.web.connector.grizzly.SocketChannelOutputBuffer.flushChannel(SocketChannelOutputBuffer.java:172) at com.sun.enterprise.web.connector.grizzly.async.AsynchronousOutputBuffer.flushChannel(AsynchronousOutputBuffer.java:81) at com.sun.enterprise.web.connector.grizzly.SocketChannelOutputBuffer.flushBuffer(SocketChannelOutputBuffer.java:205) at com.sun.enterprise.web.connector.grizzly.async.AsynchronousOutputBuffer.flushBuffer(AsynchronousOutputBuffer.java:114) at com.sun.enterprise.web.connector.grizzly.SocketChannelOutputBuffer.flush(SocketChannelOutputBuffer.java:183) at com.sun.enterprise.web.connector.grizzly.async.AsynchronousOutputBuffer.flush(AsynchronousOutputBuffer.java:104) at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.action(DefaultProcessorTask.java:1100) at org.apache.coyote.Response.action(Response.java:237) at org.apache.coyote.tomcat5.OutputBuffer.doFlush(OutputBuffer.java:381) ... 41 more |#] [#|2010-03-22T11:18:44.376+0000|WARNING|sun-appserver2.1|oracle.toplink.essentials.session.file:/mygf-211/domains/mydomain/applications/j2ee-apps/myear/myjar-myPu|_ThreadID=39;_ThreadName=httpSSLWorkerThread-8080-2;_RequestID=4ca7e3e5-5ab7-41ec-b3c9-d9260b1164c9;| Local Exception Stack: Exception [TOPLINK-4002] (Oracle TopLink Essentials - 2.1 (Build b31g-fcs (10/19/2009))): oracle.toplink.essentials.exceptions.DatabaseException Internal Exception: com.microsoft.sqlserver.jdbc.SQLServerException: Eine Zeile mit doppeltem Schlüssel kann in das 'dbo.MY_TABLE'-Objekt mit dem eindeutigen 'MY_INDEX'-Index nicht eingefügt werden.

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• C# UDP decoding datagrams fails randomly

  - by Tom Frey

  Hi, I'm experiencing an issue in a multi threaded application and have been debugging it for the last 3 days but for the life of it can not figure it out. I'm writing this, hoping that I either have a DUH moment when typing this or somebody sees something obvious in the code snippets I provide. Here's what's going on: I've been working on a new UDP networking library and have a data producer that multicasts UDP datagrams to several receiver applications. The sender sends on two different sockets that are bound to separate UDP multicast addresses and separate ports. The receiver application also creates two sockets and binds each one to one of the sender's multicast address/port. When the receiver receives the datagram, it copies it from the the buffer in a MemoryStream which is then put onto a thread safe queue, where another thread reads from it and decodes the data out of the MemoryStream. Both sockets have their own queues. What happens now is really weird, it happens randomly, non-reproducible and when I run multiple receiver applications, it only happens randomly on one of them every now and then. Basically, the thread that reads the MemoryStream out of the queue, reads it via a BinaryReader like ReadInt32(), etc. and thereby decodes the data. Every now and then however when it reads the data, the data it reads from it is incorrect, e.g. a negative integer number which the sender never would encode. However, as mentioned before, the decoding only fails in one of the receiver applications, in the other ones the datagram decodes fine. Now you might be saying, well, probably the UDP datagram has a byte corruption or something but I've logged every single datagram that's coming in and compared them on all receivers and the datagrams every application receives are absolutely identical. Now it gets even weirder, when I dump the datagram that failed to decode to disk and write a unit test that reads it and runs it through the decoder, it decodes just fine. Also when I wrap a try/catch around the decoder, reset the MemoryStream position in the catch and run it through the decoder again, it decodes just fine. To make it even weirder, this also only happens when I bind both sockets to read data from the sender, if I only bind one, it doesn't happen or at least I wasn't able to reproduce it. Here are is some corresponding code to what's going on: This is the receive callback for the socket: private void ReceiveCompleted(object sender, SocketAsyncEventArgs args) { if (args.SocketError != SocketError.Success) { InternalShutdown(args.SocketError); return; } if (args.BytesTransferred > SequencedUnitHeader.UNIT_HEADER_SIZE) { DataChunk chunk = new DataChunk(args.BytesTransferred); Buffer.BlockCopy(args.Buffer, 0, chunk.Buffer, 0, args.BytesTransferred); chunk.MemoryStream = new MemoryStream(chunk.Buffer); chunk.BinaryReader = new BinaryReader(chunk.MemoryStream); chunk.SequencedUnitHeader.SequenceID = chunk.BinaryReader.ReadUInt32(); chunk.SequencedUnitHeader.Count = chunk.BinaryReader.ReadByte(); if (prevSequenceID + 1 != chunk.SequencedUnitHeader.SequenceID) { log.Error("UdpDatagramGap\tName:{0}\tExpected:{1}\tReceived:{2}", unitName, prevSequenceID + 1, chunk.SequencedUnitHeader.SequenceID); } else if (chunk.SequencedUnitHeader.SequenceID < prevSequenceID) { log.Error("UdpOutOfSequence\tName:{0}\tExpected:{1}\tReceived:{2}", unitName, prevSequenceID + 1, chunk.SequencedUnitHeader.SequenceID); } prevSequenceID = chunk.SequencedUnitHeader.SequenceID; messagePump.Produce(chunk); } else UdpStatistics.FramesRxDiscarded++; Socket.InvokeAsyncMethod(Socket.ReceiveAsync, ReceiveCompleted, asyncReceiveArgs); } Here's some stub code that decodes the data: public static void OnDataChunk(DataChunk dataChunk) { try { for (int i = 0; i < dataChunk.SequencedUnitHeader.Count; i++) { int val = dataChunk.BinaryReader.ReadInt32(); if(val < 0) throw new Exception("EncodingException"); // do something with that value } } catch (Exception ex) { writer.WriteLine("ID:" + dataChunk.SequencedUnitHeader.SequenceID + " Count:" + dataChunk.SequencedUnitHeader.Count + " " + BitConverter.ToString(dataChunk.Buffer, 0, dataChunk.Size)); writer.Flush(); log.ErrorException("OnDataChunk", ex); log.Info("RETRY FRAME:{0} Data:{1}", dataChunk.SequencedUnitHeader.SequenceID, BitConverter.ToString(dataChunk.Buffer, 0, dataChunk.Size)); dataChunk.MemoryStream.Position = 0; dataChunk.SequencedUnitHeader.SequenceID = dataChunk.BinaryReader.ReadUInt32(); dataChunk.SequencedUnitHeader.Count = dataChunk.BinaryReader.ReadByte(); OnDataChunk(dataChunk); } } You see in the catch{} part I simply reset the MemoryStream.Position to 0 and call the same method again and it works just fine that next time? I'm really out of ideas at this point and unfortunately had no DUH moment writing this. Anybody have any kind of idea what might be going on or what else I could do to troubleshoot this? Thanks, Tom

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• Wisdom of merging 100s of Oracle instances into one instance

  - by hoytster

  Our application runs on the web, is mostly an inquiry tool, does some transactions. We host the Oracle database. The app has always had a different instance of Oracle for each customer. A customer is a company which pays us to provide our service to the company's employees, typically 10,000-25,000 employees per customer. We do a major release every few years, and migrating to that new release is challenging: we might have a team at the customer site for a couple weeks, explaining new functionality and setting up the driving data to suit that customer. We're considering going multi-client, putting all our customers into a single shared Oracle 11g instance on a big honkin' Windows Server 2008 server -- in order to reduce costs. I'm wondering if that's advisable. There are some advantages to having separate instances for each customer. Tell me if these are bogus, please. In my rough guess about decreasing importance: Our customers MyCorp and YourCo can be migrated separately when breaking changes are made to the schema. (With multi-client, we'd be migrating 300+ customers overnight!?!) MyCorp's data can be easily backed up and (!!!) restored, without affecting other customers. MyCorp's data is securely separated from their competitor YourCo's data, without depending on developers to get the code right and/or DBAs getting the configuration right. Performance is better because the database is smaller (5,000 vs 2,000,000 rows in ~50 tables). If MyCorp's offices are (mostly) in just one region, then the MyCorp's instance can be geographically co-located there, so network lag doesn't hurt performance. We can provide better service to global clients, for the same reason. In MyCorp wants to take their database in-house, then we can easily export their instance, to get MyCorp their data. Load-balancing is easier because instances can be placed on different servers (this is with a web farm). When a DEV or QA instance is needed, it's easier to clone the real instance and anonymize the data, because there's much less data. Because they're small enough, developers can have their own instance running locally, so they can work on code while waiting at the airport and while in-flight, without fighting VPN hassles. Q1: What are other advantages of separate instances? We are contemplating changing the database schema and merging all of our customers into one Oracle instance, running on one hefty server. Here are advantages of the multi-client instance approach, most important first (my WAG). Please snipe if these are bogus: Less work for the DBAs, since they only need to maintain one instance instead of hundreds. Less DBA work translates to cheaper, our main motive for this change. With just one instance, the DBAs can do a better job of optimizing performance. They'll have time to add appropriate indexes and review our SQL. It will be easier for developers to debug & enhance the application, because there is only one schema and one app (there might be dozens of schema versions if there are hundreds of instances, with a different version of the app for each version of the schema). This reduces costs too. The alternative is having to start every debug session with (1) What version is this customer running and (2) Let's struggle to recreate the corresponding development environment, code and database. (We need a Virtual Machine that includes the code AND database instance for each patch and release!) Licensing Oracle is cheaper because it's priced per server irrespective of heft (or something -- I don't know anything about the subject). The database becomes a viable persistent store for web session data, because there is just one instance. Some database operations are easier with one multi-client instance, like finding a participant when they're hazy about which customer they (or their spouse, maybe) works for: all the names are in one table. Reporting across customers is straightforward. Q2: What are other advantages of having multiple clients in one instance? Q3: Which approach do you think is better (why)? Instance per customer, or all customers in one instance? I'm concerned that having one multi-client instance makes migration near-impossible, and that's a deal killer... ... unless there is a compromise solution like having two multi-client instances, the old and the new. In that case case, we would design cross-instance solutions for finding participants, reporting, etc. so customers could go from one multi-client instance to the next without anything breaking. THANKS SO MUCH for your collective advice! This issue is beyond me -- but not beyond the collective you. :) Hoytster

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• NSOutlineView not refreshing when objects added to managed object context from NSOperations

  - by John Gallagher

  Background Cocoa app using core data Two processes - daemon and a main UI Daemon constantly writing to a data store UI process reads from same data store NSOutlineView in UI is bound to an NSTreeController which is bound to Application with key path of delegate.interpretedMOC What I want When the UI is activated, the outline view should update with the latest data inserted by the daemon. The Problem Main Thread Approach I fetch all the entities I'm interested in, then iterate over them, doing refreshObject:mergeChanges:YES. This works OK - the items get refreshed correctly. However, this is all running on the main thread, so the UI locks up for 10-20 seconds whilst it refreshes. Fine, so let's move these refreshes to NSOperations that run in the background instead. NSOperation Multithreaded Approach As soon as I move the refreshObject:mergeChanges: call into an NSOperation, the refresh no longer works. When I add logging messages, it's clear that the new objects are loaded in by the NSOperation subclass and refreshed. Not only that, but they are What I've tried I've messed around with this for 2 days solid and tried everything I can think of. Passing objectIDs to the NSOperation to refresh instead of an entity name. Resetting the interpretedMOC at various points - after the data refresh and before the outline view reload. I'd subclassed NSOutlineView. I discarded my subclass and set the view back to being an instance of NSOutlineView, just in case there was any funny goings on here. Added a rearrangeObjects call to the NSTreeController before reloading the NSOutlineView data. Made sure I had set the staleness interval to 0 on all managed object contexts I was using. I've got a feeling this problem is somehow related to caching core data objects in memory. But I've totally exhausted all my ideas on how I get this to work. I'd be eternally grateful of any ideas anyone else has. Code Main Thread Approach // In App Delegate -(void)applicationDidBecomeActive:(NSNotification *)notification { // Delay to allow time for the daemon to save [self performSelector:@selector(refreshTrainingEntriesAndGroups) withObject:nil afterDelay:3]; } -(void)refreshTrainingEntriesAndGroups { NSSet *allTrainingGroups = [[[NSApp delegate] interpretedMOC] fetchAllObjectsForEntityName:kTrainingGroup]; for(JGTrainingGroup *thisTrainingGroup in allTrainingGroups) [interpretedMOC refreshObject:thisTrainingGroup mergeChanges:YES]; NSError *saveError = nil; [interpretedMOC save:&saveError]; [windowController performSelectorOnMainThread:@selector(refreshTrainingView) withObject:nil waitUntilDone:YES]; } // In window controller class -(void)refreshTrainingView { [trainingViewTreeController rearrangeObjects]; // Didn't really expect this to have any effect. And it didn't. [trainingView reloadData]; } NSOperation Multithreaded Approach // In App Delegate -(void)refreshTrainingEntriesAndGroups { JGRefreshEntityOperation *trainingGroupRefresh = [[JGRefreshEntityOperation alloc] initWithEntityName:kTrainingGroup]; NSOperationQueue *refreshQueue = [[NSOperationQueue alloc] init]; [refreshQueue setMaxConcurrentOperationCount:1]; [refreshQueue addOperation:trainingGroupRefresh]; while ([[refreshQueue operations] count] > 0) { [[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.05]]; [windowController performSelectorOnMainThread:@selector(refreshTrainingView) withObject:nil waitUntilDone:YES]; } // JGRefreshEntityOperation.m @implementation JGRefreshEntityOperation @synthesize started; @synthesize executing; @synthesize paused; @synthesize finished; -(void)main { [self startOperation]; NSSet *allEntities = [imoc fetchAllObjectsForEntityName:entityName]; for(id thisEntity in allEntities) [imoc refreshObject:thisEntity mergeChanges:YES]; [self finishOperation]; } -(void)startOperation { [self willChangeValueForKey:@"isExecuting"]; [self willChangeValueForKey:@"isStarted"]; [self setStarted:YES]; [self setExecuting:YES]; [self didChangeValueForKey:@"isExecuting"]; [self didChangeValueForKey:@"isStarted"]; imoc = [[NSManagedObjectContext alloc] init]; [imoc setStalenessInterval:0]; [imoc setUndoManager:nil]; [imoc setPersistentStoreCoordinator:[[NSApp delegate] interpretedPSC]]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(mergeChanges:) name:NSManagedObjectContextDidSaveNotification object:imoc]; } -(void)finishOperation { saveError = nil; [imoc save:&saveError]; if (saveError) { NSLog(@"Error saving. %@", saveError); } imoc = nil; [self willChangeValueForKey:@"isExecuting"]; [self willChangeValueForKey:@"isFinished"]; [self setExecuting:NO]; [self setFinished:YES]; [self didChangeValueForKey:@"isExecuting"]; [self didChangeValueForKey:@"isFinished"]; } -(void)mergeChanges:(NSNotification *)notification { NSManagedObjectContext *mainContext = [[NSApp delegate] interpretedMOC]; [mainContext performSelectorOnMainThread:@selector(mergeChangesFromContextDidSaveNotification:) withObject:notification waitUntilDone:YES]; } -(id)initWithEntityName:(NSString *)entityName_ { [super init]; [self setStarted:false]; [self setExecuting:false]; [self setPaused:false]; [self setFinished:false]; [NSThread setThreadPriority:0.0]; entityName = entityName_; return self; } @end // JGRefreshEntityOperation.h @interface JGRefreshEntityOperation : NSOperation { NSString *entityName; NSManagedObjectContext *imoc; NSError *saveError; BOOL started; BOOL executing; BOOL paused; BOOL finished; } @property(readwrite, getter=isStarted) BOOL started; @property(readwrite, getter=isPaused) BOOL paused; @property(readwrite, getter=isExecuting) BOOL executing; @property(readwrite, getter=isFinished) BOOL finished; -(void)startOperation; -(void)finishOperation; -(id)initWithEntityName:(NSString *)entityName_; -(void)mergeChanges:(NSNotification *)notification; @end

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• capturing video from ip camera

  - by Ruby

  I am trying to capture video from ip camera into my application , its giving exception com.sun.image.codec.jpeg.ImageFormatException: Not a JPEG file: starts with 0x0d 0x0a at sun.awt.image.codec.JPEGImageDecoderImpl.readJPEGStream(Native Method) at sun.awt.image.codec.JPEGImageDecoderImpl.decodeAsBufferedImage(Unknown Source) at test.AxisCamera1.readJPG(AxisCamera1.java:130) at test.AxisCamera1.readMJPGStream(AxisCamera1.java:121) at test.AxisCamera1.readStream(AxisCamera1.java:100) at test.AxisCamera1.run(AxisCamera1.java:171) at java.lang.Thread.run(Unknown Source) its giving exception at image = decoder.decodeAsBufferedImage(); Here is the code i am trying private static final long serialVersionUID = 1L; public boolean useMJPGStream = true; public String jpgURL = "http://ip here/video.cgi/jpg/image.cgi?resolution=640×480"; public String mjpgURL = "http://ip here /video.cgi/mjpg/video.cgi?resolution=640×480"; DataInputStream dis; private BufferedImage image = null; public Dimension imageSize = null; public boolean connected = false; private boolean initCompleted = false; HttpURLConnection huc = null; Component parent; /** Creates a new instance of AxisCamera */ public AxisCamera1(Component parent_) { parent = parent_; } public void connect() { try { URL u = new URL(useMJPGStream ? mjpgURL : jpgURL); huc = (HttpURLConnection) u.openConnection(); // System.out.println(huc.getContentType()); InputStream is = huc.getInputStream(); connected = true; BufferedInputStream bis = new BufferedInputStream(is); dis = new DataInputStream(bis); if (!initCompleted) initDisplay(); } catch (IOException e) { // incase no connection exists wait and try // again, instead of printing the error try { huc.disconnect(); Thread.sleep(60); } catch (InterruptedException ie) { huc.disconnect(); connect(); } connect(); } catch (Exception e) { ; } } public void initDisplay() { // setup the display if (useMJPGStream) readMJPGStream(); else { readJPG(); disconnect(); } imageSize = new Dimension(image.getWidth(this), image.getHeight(this)); setPreferredSize(imageSize); parent.setSize(imageSize); parent.validate(); initCompleted = true; } public void disconnect() { try { if (connected) { dis.close(); connected = false; } } catch (Exception e) { ; } } public void paint(Graphics g) { // used to set the image on the panel if (image != null) g.drawImage(image, 0, 0, this); } public void readStream() { // the basic method to continuously read the // stream try { if (useMJPGStream) { while (true) { readMJPGStream(); parent.repaint(); } } else { while (true) { connect(); readJPG(); parent.repaint(); disconnect(); } } } catch (Exception e) { ; } } public void readMJPGStream() { // preprocess the mjpg stream to remove the // mjpg encapsulation readLine(3, dis); // discard the first 3 lines readJPG(); readLine(2, dis); // discard the last two lines } public void readJPG() { // read the embedded jpeg image try { JPEGImageDecoder decoder = JPEGCodec.createJPEGDecoder(dis); image = decoder.decodeAsBufferedImage(); } catch (Exception e) { e.printStackTrace(); disconnect(); } } public void readLine(int n, DataInputStream dis) { // used to strip out the // header lines for (int i = 0; i < n; i++) { readLine(dis); } } public void readLine(DataInputStream dis) { try { boolean end = false; String lineEnd = "\n"; // assumes that the end of the line is marked // with this byte[] lineEndBytes = lineEnd.getBytes(); byte[] byteBuf = new byte[lineEndBytes.length]; while (!end) { dis.read(byteBuf, 0, lineEndBytes.length); String t = new String(byteBuf); System.out.print(t); // uncomment if you want to see what the // lines actually look like if (t.equals(lineEnd)) end = true; } } catch (Exception e) { e.printStackTrace(); } } public void run() { System.out.println("in Run..................."); connect(); readStream(); } @SuppressWarnings("deprecation") public static void main(String[] args) { JFrame jframe = new JFrame(); jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); AxisCamera1 axPanel = new AxisCamera1(jframe); new Thread(axPanel).start(); jframe.getContentPane().add(axPanel); jframe.pack(); jframe.show(); } } Any suggestions what I am doing wrong here??

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• Integrate openid4java to GWT Project

  - by Slyker

  Hi, I created an GWT project in eclipse. Now I tried to implement openId with using the openid4java library. I imported the .jar files via properties--java build path: openid4java-0.9.5.jar lib/*.jar In addition I copied the .jar files into the war/WEB-INF/lib directory. The problem at hand comes up when I call the authenticate() method. Then I get a: HTTP ERROR 500 Problem accessing /openid/openid. Reason: access denied (java.lang.RuntimePermission modifyThreadGroup)Caused by:java.security.AccessControlException: access denied (java.lang.RuntimePermission modifyThreadGroup) at java.security.AccessControlContext.checkPermission(Unknown Source) at java.security.AccessController.checkPermission(Unknown Source) at java.lang.SecurityManager.checkPermission(Unknown Source) at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkPermission(DevAppServerFactory.java:166) at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkAccess(DevAppServerFactory.java:191) at java.lang.ThreadGroup.checkAccess(Unknown Source) at java.lang.Thread.init(Unknown Source) at java.lang.Thread.<init>(Unknown Source) at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$ReferenceQueueThread.<init>(MultiThreadedHttpConnectionManager.java:1039) at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager.storeReferenceToConnection(MultiThreadedHttpConnectionManager.java:164) at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager.access$900(MultiThreadedHttpConnectionManager.java:64) at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$ConnectionPool.createConnection(MultiThreadedHttpConnectionManager.java:750) at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager.doGetConnection(MultiThreadedHttpConnectionManager.java:469) at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager.getConnectionWithTimeout(MultiThreadedHttpConnectionManager.java:394) at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:152) at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:396) at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:324) at org.openid4java.util.HttpCache.head(HttpCache.java:296) at org.openid4java.discovery.yadis.YadisResolver.retrieveXrdsLocation(YadisResolver.java:360) at org.openid4java.discovery.yadis.YadisResolver.discover(YadisResolver.java:229) at org.openid4java.discovery.yadis.YadisResolver.discover(YadisResolver.java:221) at org.openid4java.discovery.yadis.YadisResolver.discover(YadisResolver.java:179) at org.openid4java.discovery.Discovery.discover(Discovery.java:134) at org.openid4java.discovery.Discovery.discover(Discovery.java:114) at org.openid4java.consumer.ConsumerManager.discover(ConsumerManager.java:527) at auth.openid.server.OpenIDServlet.authenticate(OpenIDServlet.java:138) at auth.openid.server.OpenIDServlet.doGet(OpenIDServlet.java:101) at javax.servlet.http.HttpServlet.service(HttpServlet.java:693) at javax.servlet.http.HttpServlet.service(HttpServlet.java:806) at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:51) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:349) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at org.mortbay.jetty.Server.handle(Server.java:326) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923) at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547) at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582) Here my servlet source: import com.google.gwt.user.client.rpc.RemoteService; import org.openid4java.OpenIDException; import org.openid4java.consumer.ConsumerException; import org.openid4java.consumer.ConsumerManager; import org.openid4java.consumer.VerificationResult; import org.openid4java.discovery.DiscoveryInformation; import org.openid4java.discovery.Identifier; import org.openid4java.message.AuthRequest; import org.openid4java.message.ParameterList; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.text.MessageFormat; import java.util.List; public final class OpenIDServlet extends HttpServlet implements RemoteService { private final ConsumerManager manager; public OpenIDServlet() { try { manager = new ConsumerManager(); } catch (ConsumerException e) { throw new RuntimeException("Error creating consumer manager", e); } } ... private void authenticate(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { final String loginString = request.getParameter(nameParameter); try { // perform discovery on the user-supplied identifier List discoveries = manager.discover(loginString); // attempt to associate with the OpenID provider // and retrieve one service endpoint for authentication DiscoveryInformation discovered = manager.associate(discoveries); // obtain a AuthRequest message to be sent to the OpenID provider AuthRequest authReq = manager.authenticate(discovered, "openid", null); // redirect to OpenID for authentication response.sendRedirect(authReq.getDestinationUrl(true)); } catch (OpenIDException e) { throw new ServletException("Login string probably caused an error. loginString = " + loginString, e); } } My question now is: What could be my fault? Did I make any mistakes in importing the openid4java library? (which?) All other methods in the servlet which do not use the openid4java implementation work fine. Thanks, Andreas

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• Sorting/Paginating/Filtering Complex Multi-AR Object Tables in Rails

  - by Matt Rogish

  I have a complex table pulled from a multi-ActiveRecord object array. This listing is a combined display of all of a particular user's "favorite" items (songs, messages, blog postings, whatever). Each of these items is a full-fledged AR object. My goal is to present the user with a simplified search, sort, and pagination interface. The user need not know that the Song has a singer, and that the Message has an author -- to the end user both entries in the table will be displayed as "User". Thus, the search box will simply be a dropdown list asking them which to search on (User name, created at, etc.). Internally, I would need to convert that to the appropriate object search, combine the results, and display. I can, separately, do pagination (mislav will_paginate), sorting, and filtering, but together I'm having some problems combining them. For example, if I paginate the combined list of items, the pagination plugin handles it just fine. It is not efficient since the pagination is happening in the app vs. the DB, but let's assume the intended use-case would indicate the vast majority of the users will have less than 30 favorited items and all other behavior, server capabilities, etc. indicates this will not be a bottleneck. However, if I wish to sort the list I cannot sort it via the pagination plugin because it relies on the assumption that the result set is derived from a single SQL query, and also that the field name is consistent throughout. Thus, I must sort the merged array via ruby, e.g. @items.sort_by{ |i| i.whatever } But, since the items do not share common names, I must first interrogate the object and then call the correct sort by. For example, if the user wishes to sort by user name, if the sorted object is a message, I sort by author but if the object is a song, I sort by singer. This is all very gross and feels quite un-ruby-like. This same problem comes into play with the filter. If the user filters on the "parent item" (the message's thread, the song's album), I must translate that to the appropriate collection object method. Also gross. This is not the exact set-up but is close enough. Note that this is a legacy app so changing it is quite difficult, although not impossible. Also, yes there is some DRY that can be done, but don't focus on the style or elegance of the following code. Style/elegance of the SOLUTION is important, however! :D models: class User < ActiveRecord::Base ... has_and_belongs_to_many :favorite_messages, :class_name => "Message" has_and_belongs_to_many :favorite_songs, :class_name => "Song" has_many :authored_messages, :class_name => "Message" has_many :sung_songs, :class_name => "Song" end class Message < ActiveRecord::Base has_and_belongs_to_many :favorite_messages belongs_to :author, :class_name => "User" belongs_to :thread end class Song < ActiveRecord::Base has_and_belongs_to_many :favorite_songs belongs_to :singer, :class_name => "User" belongs_to :album end controller: def show u = User.find 123 @items = Array.new @items << u.favorite_messages @items << u.favorite_songs # etc. etc. @items.flatten! @items = @items.sort_by{ |i| i.created_at } @items = @items.paginate :page => params[:page], :per_page => 20 end def search # Assume user is searching for username like 'Bob' u = User.find 123 @items = Array.new @items << u.favorite_messages.find( :all, :conditions => "LOWER( author ) LIKE LOWER('%bob%')" ) @items << u.favorite_songs.find( :all, :conditions => "LOWER( singer ) LIKE ... " ) # etc. etc. @items.flatten! @items = @items.sort_by{ |i| determine appropriate sorting based on user selection } @items = @items.paginate :page => params[:page], :per_page => 20 end view: #index.html.erb ... <table> <tr> <th>Title (sort ASC/DESC links)</th> <th>Created By (sort ASC/DESC links))</th> <th>Collection Title (sort ASC/DESC links)</th> <th>Created At (sort ASC/DESC links)</th> </tr> <% @items.each |item| do %> <%= render { :partial => "message", :locals => item } if item.is_a? Message %> <%= render { :partial => "song", :locals => item } if item.is_a? Song %> <%end%> ... </table> #message.html.erb # shorthand, not real ruby print out message title, author name, thread title, message created at #song.html.erb # shorthand print out song title, singer name, album title, song created at

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• [Android] Force close when trying to parse JSON with AsyncTask in the background

  - by robs

  Hello everyone, i'm new to android development and i'm playing around with json data. I managed to get the parsing to work. I want to show a ProgressDialog and i read that i need to use AsyncTask that. But for some reason i get a force close as soon as i put the same working code inside doInBackground() eventhough eclipse says everything is fine. Here is the source code: public class HomeActivity extends Activity { public class BackgroundAsyncTask extends AsyncTask<Void, Integer, Void> { ProgressDialog dialog = new ProgressDialog (HomeActivity.this); @Override protected void onPreExecute() { dialog.setMessage("Loading...please wait"); dialog.setIndeterminate(true); dialog.setCancelable(false); dialog.show(); } protected void onPostExecute() { dialog.dismiss(); } @Override protected Void doInBackground(Void... params) { try { URL json = new URL("http://www.corps-marchia.de/jsontest.php"); URLConnection tc = json.openConnection(); BufferedReader in = new BufferedReader(new InputStreamReader(tc.getInputStream())); String line; while ((line = in.readLine()) != null) { JSONArray ja = new JSONArray(line); JSONObject jo = (JSONObject) ja.get(0); TextView txtView = (TextView)findViewById(R.id.TextView01); txtView.setText(jo.getString("text")); } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (JSONException e) { e.printStackTrace(); } return null; } } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); new BackgroundAsyncTask().execute(); } } Here is the error log: 01-08 12:33:48.225: ERROR/AndroidRuntime(815): FATAL EXCEPTION: AsyncTask #1 01-08 12:33:48.225: ERROR/AndroidRuntime(815): java.lang.RuntimeException: An error occured while executing doInBackground() 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.os.AsyncTask$3.done(AsyncTask.java:200) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at java.util.concurrent.FutureTask.setException(FutureTask.java:125) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at java.util.concurrent.FutureTask.run(FutureTask.java:138) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at java.lang.Thread.run(Thread.java:1019) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): Caused by: android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views. 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.view.ViewRoot.checkThread(ViewRoot.java:2932) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.view.ViewRoot.requestLayout(ViewRoot.java:629) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.view.View.requestLayout(View.java:8267) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.view.View.requestLayout(View.java:8267) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.view.View.requestLayout(View.java:8267) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.view.View.requestLayout(View.java:8267) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.view.View.requestLayout(View.java:8267) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.widget.TextView.checkForRelayout(TextView.java:5521) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.widget.TextView.setText(TextView.java:2724) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.widget.TextView.setText(TextView.java:2592) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.widget.TextView.setText(TextView.java:2567) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at net.ajzele.demo.andy1.HomeActivity$BackgroundAsyncTask.doInBackground(HomeActivity.java:52) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at net.ajzele.demo.andy1.HomeActivity$BackgroundAsyncTask.doInBackground(HomeActivity.java:1) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at android.os.AsyncTask$2.call(AsyncTask.java:185) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306) 01-08 12:33:48.225: ERROR/AndroidRuntime(815): ... 4 more 01-08 12:33:51.605: ERROR/WindowManager(815): Activity net.ajzele.demo.andy1.HomeActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4051d0c0 that was originally added here 01-08 12:33:51.605: ERROR/WindowManager(815): android.view.WindowLeaked: Activity net.ajzele.demo.andy1.HomeActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4051d0c0 that was originally added here 01-08 12:33:51.605: ERROR/WindowManager(815): at android.view.ViewRoot.<init>(ViewRoot.java:258) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.view.Window$LocalWindowManager.addView(Window.java:424) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.app.Dialog.show(Dialog.java:241) 01-08 12:33:51.605: ERROR/WindowManager(815): at net.ajzele.demo.andy1.HomeActivity$BackgroundAsyncTask.onPreExecute(HomeActivity.java:33) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.os.AsyncTask.execute(AsyncTask.java:391) 01-08 12:33:51.605: ERROR/WindowManager(815): at net.ajzele.demo.andy1.HomeActivity.onCreate(HomeActivity.java:72) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1586) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1638) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:928) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.os.Handler.dispatchMessage(Handler.java:99) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.os.Looper.loop(Looper.java:123) 01-08 12:33:51.605: ERROR/WindowManager(815): at android.app.ActivityThread.main(ActivityThread.java:3647) 01-08 12:33:51.605: ERROR/WindowManager(815): at java.lang.reflect.Method.invokeNative(Native Method) 01-08 12:33:51.605: ERROR/WindowManager(815): at java.lang.reflect.Method.invoke(Method.java:507) 01-08 12:33:51.605: ERROR/WindowManager(815): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 01-08 12:33:51.605: ERROR/WindowManager(815): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 01-08 12:33:51.605: ERROR/WindowManager(815): at dalvik.system.NativeStart.main(Native Method) Any hints? I hope you can help me out ive searched the net and didnt find any working solution...Thanks in advance

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• PERL XPath Parser Help

  - by cognvision

  I want to pull in data using a XML::XPath parser from a XML DB file from the Worldbank site. The problem is that I'm not seeing any results in the output. I must be missing something in the code. Ideally, I would like to extract just the death rate statistics from each country XML DB (year and value). I'm using this as part of my input: http://data.worldbank.org/sites/default/files/countries/en/afghanistan_en.xml use strict; use LWP 5.64; use HTML::ContentExtractor; use XML::XPath; my $agent1 = LWP::UserAgent->new; my $extractor = HTML::ContentExtractor->new(); #Retrieve main Worldbank country site my $mainlink = "http://data.worldbank.org/country/"; my $page = $agent1->get("$mainlink"); my $fulltext = $page->decoded_content(); #Match to just all available countries in Worldbank my $country = ""; my @countryList; if (@countryList = $fulltext =~ m/(http:\/\/data\.worldbank\.org\/country\/.*?")/gi){ foreach $country(@countryList){ #Remove " at the end of link $country=~s/\"//gi; print "\n" . $country; #Retrieve each country profile's XML DB file my $page = $agent1->get("$country"); my $fulltext = $page->decoded_content(); my $XML_DB = ""; my @countryXMLDBList; if (@countryXMLDBList = $fulltext =~ m/(http:\/\/data\.worldbank\.org\/sites\/default\/files\/countries\/en\/.*?\.xml)/gi){ foreach $XML_DB(@countryXMLDBList){ my $page = $agent1->get("$XML_DB"); my $fulltext = $page->decoded_content(); #print $fulltext; #Use XML XPath parser to find elements related to death rate my $xp = XML::XPath->new($fulltext); #my $xp = XML::XPath->new("afghanistan_en.xml"); my $nodeSet = $xp->find("//*"); if (!$nodeSet->isa('XML::XPath::NodeSet') || $nodeSet->size() == 0) { #No match found print "\nMatch not found!"; exit; } else { foreach my $node ($nodeSet->get_nodelist){ print "\n" . $node->find('country')->string_value; print "\n" . $node->find('indicator')->string_value; print "\n" . $node->find('year')->string_value; print "\n" . $node->find('value')->string_value; exit; } } } #Build line graph based on death rate statistics and output some image file format } } } I am also looking into using the xpath expression "following-sibling", but not sure how to use it correctly. For example, I have the following set of XML data where I am only interested in pulling siblings directly after the indicator for just death rate data. <data> <country id="AFG">Afghanistan</country> <indicator id="SP.DYN.CDRT.IN">Death rate, crude (per 1,000 people)</indicator> <year>2006</year> <value>20.3410000</value> </data> - <data> <country id="AFG">Afghanistan</country> <indicator id="SP.DYN.CDRT.IN">Death rate, crude (per 1,000 people)</indicator> <year>2007</year> <value>19.9480000</value> </data> - <data> <country id="AFG">Afghanistan</country> <indicator id="SP.DYN.CDRT.IN">Death rate, crude (per 1,000 people)</indicator> <year>2008</year> <value>19.5720000</value> </data> - <data> <country id="AFG">Afghanistan</country> <indicator id="IC.EXP.DOCS">Documents to export (number)</indicator> <year>2005</year> <value>7.0000000</value> </data> - <data> <country id="AFG">Afghanistan</country> <indicator id="IC.EXP.DOCS">Documents to export (number)</indicator> <year>2006</year> <value>12.0000000</value> </data> - <data> <country id="AFG">Afghanistan</country> <indicator id="IC.EXP.DOCS">Documents to export (number)</indicator> <year>2007</year> <value>12.0000000</value> </data> Any help would be much appreciated!!!

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• Something like a manual refresh is needed angularjs, and a $digest() iterations error

  - by Tony Ennis

  (post edited again, new comments follow this line) I'm changing the title of this posting since it was misleading - I was trying to fix a symptom. I was unable to figure out why the code was breaking with a $digest() iterations error. A plunk of my code worked fine. I was totally stuck, so I decided to make my code a little more Angular-like. One anti-pattern I had implemented was to hide my model behind my controller by adding getters/setters to the controller. I tore all that out and instead put the model into the $scope since I had read that was proper Angular. To my surprise, the $digest() iterations error went away. I do not exactly know why and I do not have the intestinal fortitude to put the old code back and figure it out. I surmise that by involving the controller in the get/put of the data I added a dependency under the hood. I do not understand it. edit #2 ends here. (post edited, see EDIT below) I was working through my first Error: 10 $digest() iterations reached. Aborting! error today. I solved it this way: <div ng-init="lineItems = ctrl.getLineItems()"> <tr ng-repeat="r in lineItems"> <td>{{r.text}}</td> <td>...</td> <td>{{r.price | currency}}</td> </tr </div> Now a new issue has arisen - the line items I'm producing can be modified by another control on the page. It's a text box for a promo code. The promo code adds a discount to the lineItem array. It would show up if I could ng-repeat over ctrl.getLineItems(). Since the ng-repeat is looking at a static variable, not the actual model, it doesn't see that the real line items have changed and thus the promotional discount doesn't get displayed until I refresh the browser. Here's the HTML for the promo code: <input type="text" name="promo" ng-model="ctrl.promoCode"/> <button ng-click="ctrl.applyPromoCode()">apply promo code</button> The input tag is writing the value to the model. The bg-click in the button is invoking a function that will apply the code. This could change the data behind the lineItems. I have been advised to use $scope.apply(...). However, since this is applied as a matter of course by ng-click is isn't going to do anything. Indeed, if I add it to ctrl.applyPromoCode(), I get an error since an .apply() is already in progress. I'm at a loss. EDIT The issue above is probably the result of me fixing of symptom, not a problem. Here is the original HTML that was dying with the 10 $digest() iterations error. <table> <tr ng-repeat="r in ctrl.getLineItems()"> <td>{{r.text}}</td> <td>...</td> <td>{{r.price | currency}}</td> </tr> </table> The ctrl.getLineItems() function doesn't do much but invoke a model. I decided to keep the model out of the HTML as much as I could. this.getLineItems = function() { var total = 0; this.lineItems = []; this.lineItems.push({text:"Your quilt will be "+sizes[this.size].block_size+" squares", price:sizes[this.size].price}); total = sizes[this.size].price; this.lineItems.push({text: threads[this.thread].narrative, price:threads[this.thread].price}); total = total + threads[this.thread].price; if (this.sashing) { this.lineItems.push({text:"Add sashing", price: this.getSashingPrice()}); total = total + sizes[this.size].sashing; } else { this.lineItems.push({text:"No sashing", price:0}); } if(isNaN(this.promo)) { this.lineItems.push({text:"No promo code", price:0}); } else { this.lineItems.push({text:"Promo code", price: promos[this.promo].price}); total = total + promos[this.promo].price; } this.lineItems.push({text:"Shipping", price:this.shipping}); total = total + this.shipping; this.lineItems.push({text:"Order Total", price:total}); return this.lineItems; }; And the model code assembled an array of objects based upon the items selected. I'll abbreviate the class as it croaks as long as the array has a row. function OrderModel() { this.lineItems = []; // Result of the lineItems call ... this.getLineItems = function() { var total = 0; this.lineItems = []; ... this.lineItems.push({text:"Order Total", price:total}); return this.lineItems; }; }

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