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• WLI domain with 3 servers - issues on JPD process startup

  - by XpiritO

  Hi there. I'm currently working on a clustered WLI environment which comprehends 3 servers: 1 admin server ("AdminServer") and 2 managed servers ("mn1" and "mn2") grouped as a cluster, as follows: Architecture diagram: http://img72.imageshack.us/img72/4112/clusterdiagram.jpg I've developed a JPD process to execute some scheduled tasks, invoked using a Message Broker. I've deployed this project into a single-server WLI domain (with AdminServer only) and it works as expected: the JPD process is invoked (I've configured a Timer Event Generator instance to start it up). Message broker: http://img532.imageshack.us/img532/1443/wlimessagebroker.jpg Timer event generator: http://img408.imageshack.us/img408/7358/wlitimereventgenerator.jpg In order to achieve fail-over and load-balancing capabilities, I'm currently trying to deploy this JPD process into this clustered WLI environment. Although, I'm having some issues with this, as I cannot get it to work properly, even if it still works. Here is a screenshot of the "WLI Process Instance Monitor" (with AdminServer and mn1 instances up and running): http://img710.imageshack.us/img710/8477/wliprocessinstancemonit.jpg According to this screen the process seems to be running, as it shows in this instance monitor screen. However, I don't see any output coming out neither at AdminServer console or mn1 console. In single-server domain it was visible output from JPD process "timeout" callback method, wich implementation is shown below: @com.bea.wli.control.broker.MessageBroker.StaticSubscription(xquery = "", filterValueMatch = "", channelName = "/SamplePrefix/Samples/SampleStringChannel", messageBody = "{x0}") public void subscription(java.lang.String x0) { String toReturn=""; try { Context myCtx = new InitialContext(); MBeanHome mbeanHome = (MBeanHome)myCtx.lookup("weblogic.management.home.localhome"); toReturn=mbeanHome.getMBeanServer().getServerName(); System.out.println("**** executed at **** " + System.currentTimeMillis() + " by: " + toReturn); } catch (Exception e) { System.out.println("Exception!"); e.printStackTrace(); } } (...) @org.apache.beehive.controls.api.events.EventHandler(field = "myT", eventSet = com.bea.control.WliTimerControl.Callback.class, eventName = "onTimeout") public void myT_onTimeout(long time, java.io.Serializable data) { // #START: CODE GENERATED - PROTECTED SECTION - you can safely add code above this comment in this method. #// // input transform System.out.println("**** published at **** " + System.currentTimeMillis()); publishControl.publish("aaaa"); // parameter assignment // #END : CODE GENERATED - PROTECTED SECTION - you can safely add code below this comment in this method. #// } and here is the output visible at "AdminServer" console in single-server domain testing: **** published at **** 1273238090713 **** executed at **** 1273238132123 by: AdminServer **** published at **** 1273238152462 **** executed at **** 1273238152562 by: AdminServer (...) What may be wrong with my clustered configuration? Am I missing something to accomplish clustered deployment? Thanks in advance for your help.

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• Objective-c design advice for use of different data sources, swapping between test and live

  - by user200341

  I'm in the process of designing an application that is part of a larger piece of work, depending on other people to build an API that the app can make use of to retrieve data. While I was thinking about how to setup this project and design the architecture around it, something occurred to me, and I'm sure many people have been in similar situations. Since my work is depending on other people to complete their tasks, and a test server, this slows work down at my end. So the question is: What's the best practice for creating test repositories and classes, implementing them, and not having to depend on altering several places in the code to swap between the test classes and the actual repositories / proper api calls. Contemplate the following scenario: GetDataFromApiCommand *getDataCommand = [[GetDataFromApiCommand alloc]init]; getDataCommand.delegate = self; [getDataCommand getData]; Once the data is available via the API, "GetDataFromApiCommand" could use the actual API, but until then a set of mock data could be returned upon the call of [getDataCommand getData] There might be multiple instances of this, in various places in the code, so replacing all of them wherever they are, is a slow and painful process which inevitably leads to one or two being overlooked. In strongly typed languages we could use dependency injection and just alter one place. In objective-c a factory pattern could be implemented, but is that the best route to go for this? GetDataFromApiCommand *getDataCommand = [GetDataFromApiCommandFactory buildGetDataFromApiCommand]; getDataCommand.delegate = self; [getDataCommand getData]; What is the best practices to achieve this result? Since this would be most useful, even if you have the actual API available, to run tests, or work off-line, the ApiCommands would not necessarily have to be replaced permanently, but the option to select "Do I want to use TestApiCommand or ApiCommand". It is more interesting to have the option to switch between: All commands are test and All command use the live API, rather than selecting them one by one, however that would also be useful to do for testing one or two actual API commands, mixing them with test data. EDIT The way I have chosen to go with this is to use the factory pattern. I set up the factory as follows: @implementation ApiCommandFactory + (ApiCommand *)newApiCommand { // return [[ApiCommand alloc]init]; return [[ApiCommandMock alloc]init]; } @end And anywhere I want to use the ApiCommand class: GetDataFromApiCommand *getDataCommand = [ApiCommandFactory newApiCommand]; When the actual API call is required, the comments can be removed and the mock can be commented out. Using new in the message name implies that who ever uses the factory to get an object, is responsible for releasing it (since we want to avoid autorelease on the iPhone). If additional parameters are required, the factory needs to take these into consideration i.e: [ApiCommandFactory newSecondApiCommand:@"param1"]; This will work quite well with repositories as well.

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• Custom Tag implementation issue

  - by Appps

  I have a custom tag as follows. repeat and heading tag have doAfterBody method implemented. <csajsp:repeat reps="5"> <LI> <csajsp:heading bgColor="BLACK"> White on Black Heading </csajsp:heading> </LI> </csajsp:repeat> /* Repeat tag Class*/ public void setReps(String repeats) { System.out.println("TESTING"+repeats); //sets the reps variable. } public int doAfterBody() { System.out.println("Inside repeate tag"+reps); if (reps-- >= 1) { BodyContent body = getBodyContent(); try { JspWriter out = body.getEnclosingWriter(); System.out.println("BODY"+body.getString()); out.println(body.getString()); body.clearBody(); // Clear for next evaluation } catch(IOException ioe) { System.out.println("Error in RepeatTag: " + ioe); } return(EVAL_BODY_TAG); } else { return(SKIP_BODY); } } /* Class of Heading tag */ public int doAfterBody() { System.out.println("inside heading tag"); BodyContent body = getBodyContent(); System.out.println(body.getString()); try { JspWriter out = body.getEnclosingWriter(); out.print("NEW TEXT"); } catch(IOException ioe) { System.out.println("Error in FilterTag: " + ioe); } // SKIP_BODY means I'm done. If I wanted to evaluate // and handle the body again, I'd return EVAL_BODY_TAG. return(SKIP_BODY); } public int doEndTag() { try { JspWriter out = pageContext.getOut(); out.print("NEW TEXT 2"); } catch(IOException ioe) { System.out.println("Error in HeadingTag: " + ioe); } return(EVAL_PAGE); // Continue with rest of JSP page } The order in which SOP are printed is 1) Setter method of csajsp:repeat is called. 2) White on Black Heading is printed. ie doAfterBody of csajsp:heading tag is called. I don't know why it is not calling doAfterBody of csajsp:repeat tag. Please help me to understand this. Thanks in advance.

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• Dependency Injection: I don't get where to start!

  - by Andy

  I have several articles about Dependency Injection, and I can see the benefits, especially when it comes to unit testing. The units can me loosely coupled, and mocking of dependencies can be made. The trouble is - I just don't get where to start. Consider this snippet below of (much edited for the purpose of this post) code that I have. I am instantiating a Plc object from the main form, and passing in a communications mode via the Connect method. In it's present form it becomes hard to test, because I can't isolate the Plc from the CommsChannel to unit test it. (Can I?) The class depends on using a CommsChannel object, but I am only passing in a mode that is used to create this channel within the Plc itself. To use dependancy injection, I should really pass in an already created CommsChannel (via an 'ICommsChannel' interface perhaps) to the Connect method, or maybe via the Plc constructor. Is that right? But then that would mean creating the CommsChannel in my main form first, and this doesn't seem right either, because it feels like everything will come back to the base layer of the main form, where everything begins. Somehow it feels like I am missing a crucial piece of the puzzle. Where do you start? You have to create an instance of something somewhere, but I'm struggling to understand where that should be. public class Plc() { public bool Connect(CommsMode commsMode) { bool success = false; // Create new comms channel. this._commsChannel = this.GetCommsChannel(commsMode); // Attempt connection success = this._commsChannel.Connect(); return this._connected; } private CommsChannel GetCommsChannel(CommsMode mode) { CommsChannel channel; switch (mode) { case CommsMode.RS232: channel = new SerialCommsChannel( SerialCommsSettings.Default.ComPort, SerialCommsSettings.Default.BaudRate, SerialCommsSettings.Default.DataBits, SerialCommsSettings.Default.Parity, SerialCommsSettings.Default.StopBits); break; case CommsMode.Tcp: channel = new TcpCommsChannel( TCPCommsSettings.Default.IP_Address, TCPCommsSettings.Default.Port); break; default: // Throw unknown comms channel exception. } return channel; } }

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• Reading and writing C++ vector to a file

  - by JB

  For some graphics work I need to read in a large amount of data as quickly as possible and would ideally like to directly read and write the data structures to disk. Basically I have a load of 3d models in various file formats which take too long to load so I want to write them out in their "prepared" format as a cache that will load much faster on subsequent runs of the program. Is it safe to do it like this? My worries are around directly reading into the data of the vector? I've removed error checking, hard coded 4 as the size of the int and so on so that i can give a short working example, I know it's bad code, my question really is if it is safe in c++ to read a whole array of structures directly into a vector like this? I believe it to be so, but c++ has so many traps and undefined behavour when you start going low level and dealing directly with raw memory like this. I realise that number formats and sizes may change across platforms and compilers but this will only even be read and written by the same compiler program to cache data that may be needed on a later run of the same program. #include <fstream> #include <vector> using namespace std; struct Vertex { float x, y, z; }; typedef vector<Vertex> VertexList; int main() { // Create a list for testing VertexList list; Vertex v1 = {1.0f, 2.0f, 3.0f}; list.push_back(v1); Vertex v2 = {2.0f, 100.0f, 3.0f}; list.push_back(v2); Vertex v3 = {3.0f, 200.0f, 3.0f}; list.push_back(v3); Vertex v4 = {4.0f, 300.0f, 3.0f}; list.push_back(v4); // Write out a list to a disk file ofstream os ("data.dat", ios::binary); int size1 = list.size(); os.write((const char*)&size1, 4); os.write((const char*)&list[0], size1 * sizeof(Vertex)); os.close(); // Read it back in VertexList list2; ifstream is("data.dat", ios::binary); int size2; is.read((char*)&size2, 4); list2.resize(size2); // Is it safe to read a whole array of structures directly into the vector? is.read((char*)&list2[0], size2 * sizeof(Vertex)); }

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• how get fully result from Asynchronism communication?

  - by rima

  Hi all refer to these post : here1 and here2 at last I solve my problem by build a asynchronous solution,and it work well!!! but there is a problem that i face with it,now my code is like this: class MyProcessStarter { private Process process; private StreamWriter myStreamWriter; private static StringBuilder shellOutput = null; public String GetShellOutput { get { return shellOutput.ToString(); }} public MyProcessStarter(){ shellOutput = new StringBuilder(""); process = new Process(); process.StartInfo.FileName = "sqlplus"; process.StartInfo.UseShellExecute = false; process.StartInfo.CreateNoWindow = true; process.OutputDataReceived += new DataReceivedEventHandler(ShellOutputHandler); process.StartInfo.RedirectStandardInput = true; process.StartInfo.RedirectStandardOutput = true; //process.StartInfo.RedirectStandardError = true; process.Start(); myStreamWriter = process.StandardInput; process.BeginOutputReadLine(); } private static void ShellOutputHandler(object sendingProcess,DataReceivedEventArgs outLine) { if (!String.IsNullOrEmpty(outLine.Data)) shellOutput.Append(Environment.NewLine + outLine.Data); } public void closeConnection() { myStreamWriter.Close(); process.WaitForExit(); process.Close(); } public void RunCommand(string arguments) { myStreamWriter.WriteLine(arguments); myStreamWriter.Flush(); process.WaitForExit(100); Console.WriteLine(shellOutput); Console.WriteLine("============="+Environment.NewLine); process.WaitForExit(2000); Console.WriteLine(shellOutput); } } and my input is like this: myProcesStarter.RunCommand("myusername/mypassword"); Console.writeline(myProcesStarter.GetShellOutput); but take a look at my out put: SQL*Plus: Release 11.1.0.6.0 - Production on Thu May 20 11:57:38 2010 Copyright (c) 1982, 2007, Oracle. All rights reserved. ============= SQL*Plus: Release 11.1.0.6.0 - Production on Thu May 20 11:57:38 2010 Copyright (c) 1982, 2007, Oracle. All rights reserved. Enter user-name: Connected to: Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production With the Partitioning, OLAP, Data Mining and Real Application Testing options as u see the output for run a function is not same in different time!So now would you do me a faver and help me that how I can wait until all the output done in other mean how I can customize my process to wait until output finishing ?? because I want to write a sqlcompiler so I need the exact output of shell. plz help me soon.thanxxxxxxxxxxxx :X

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• translating specifications into query predicates

  - by Jeroen

  I'm trying to find a nice and elegant way to query database content based on DDD "specifications". In domain driven design, a specification is used to check if some object, also known as the candidate, is compliant to a (domain specific) requirement. For example, the specification 'IsTaskDone' goes like: class IsTaskDone extends Specification<Task> { boolean isSatisfiedBy(Task candidate) { return candidate.isDone(); } } The above specification can be used for many purposes, e.g. it can be used to validate if a task has been completed, or to filter all completed tasks from a collection. However, I want to re-use this, nice, domain related specification to query on the database. Of course, the easiest solution would be to retrieve all entities of our desired type from the database, and filter that list in-memory by looping and removing non-matching entities. But clearly that would not be optimal for performance, especially when the entity count in our db increases. Proposal So my idea is to create a 'ConversionManager' that translates my specification into a persistence technique specific criteria, think of the JPA predicate class. The services looks as follows: public interface JpaSpecificationConversionManager { <T> Predicate getPredicateFor(Specification<T> specification, Root<T> root, CriteriaQuery<?> cq, CriteriaBuilder cb); JpaSpecificationConversionManager registerConverter(JpaSpecificationConverter<?, ?> converter); } By using our manager, the users can register their own conversion logic, isolating the domain related specification from persistence specific logic. To minimize the configuration of our manager, I want to use annotations on my converter classes, allowing the manager to automatically register those converters. JPA repository implementations could then use my manager, via dependency injection, to offer a find by specification method. Providing a find by specification should drastically reduce the number of methods on our repository interface. In theory, this all sounds decent, but I feel like I'm missing something critical. What do you guys think of my proposal, does it comply to the DDD way of thinking? Or is there already a framework that does something identical to what I just described?

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• Specifying a Single Request To Use Credentials with HttpClient

  - by jiduvah

  I am using OAuth2 on my android project. The idea is to use a singleton HttpClient used with a ThreadSafeClientConnManager. For a normal request to the server we construct an Authorization header and send that. The header is constructed from values received from the server. This works fine. However every 15 minutes we must get new values from the server to construct the header. To Received these values I must set the credentials like so. client.getCredentialsProvider().setCredentials( new AuthScope(AuthScope.ANY_HOST, AuthScope.ANY_PORT), new UsernamePasswordCredentials(creds.clientId, creds.clientSecret)); In order for this to work I must set up and new DefaultHttpClient. If I use the original singleton httpclient I receive some errors. My question is.. is it possible to set the credentials to be used only on this one request? I noticed that there is an AuthScope. The host and port would not be suitable for this but maybe the realm would? I can't find anything that tells me what a realm is or how to use it. 06-05 10:12:55.969: W/System.err(23843): org.apache.http.NoHttpResponseException: The target server failed to respond 06-05 10:12:55.969: W/System.err(23843): at org.apache.http.impl.conn.DefaultResponseParser.parseHead(DefaultResponseParser.java:85) 06-05 10:12:55.969: W/System.err(23843): at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:174) 06-05 10:12:55.969: W/System.err(23843): at org.apache.http.impl.AbstractHttpClientConnection.receiveResponseHeader(AbstractHttpClientConnection.java:179) 06-05 10:12:55.969: W/System.err(23843): at org.apache.http.impl.conn.DefaultClientConnection.receiveResponseHeader(DefaultClientConnection.java:235) 06-05 10:12:55.969: W/System.err(23843): at org.apache.http.impl.conn.AbstractClientConnAdapter.receiveResponseHeader(AbstractClientConnAdapter.java:259) 06-05 10:12:55.975: W/System.err(23843): at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:279) 06-05 10:12:55.975: W/System.err(23843): at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:121) 06-05 10:12:55.975: W/System.err(23843): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:504) 06-05 10:12:55.975: W/System.err(23843): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 06-05 10:12:55.975: W/System.err(23843): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 06-05 10:12:55.975: W/System.err(23843): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) So After more testing I have found where the problem lies. I want to configure a pooled connection manager like so SchemeRegistry schemeRegistry = new SchemeRegistry(); schemeRegistry.register( new Scheme("http", PlainSocketFactory.getSocketFactory(), 80)); schemeRegistry.register( new Scheme("https", PlainSocketFactory.getSocketFactory(), 443)); ClientConnectionManager conManager = new ThreadSafeClientConnManager(new BasicHttpParams(), schemeRegistry); DefaultHttpClient httpClient = new DefaultHttpClient(); But when configure like this, I get the error above. If I use the normal default httpclient like so DefaultHttpClient httpClient = new DefaultHttpClient(); Then it works fine. Any ideas?

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• Large number of UPDATE queries slowing down page

  - by Bryan Lewis

  I am reading and validating large fixed-width text files (range from 10-50K lines) that are submitted via our ASP.net website (coded in VB.Net). I do an initial scan of the file to check for basic issues (line length, etc). Then I import each row into a MS SQL table. Each DB rows basically consists of a record_ID (Primary, auto-incrementing) and about 50 varchar fields. After the insert is done, I run a validation function on the file that checks each field in each row based on a bunch of criteria (trimmed length, isnumeric, range checks, etc). If it finds an error in any field, it inserts a record into the Errors table, which has an error_ID, the record_ID and an error message. In addition, if the field fails in a particular way, I have to do a "reset" on that field. A reset might consist of blanking the entire field, or simply replacing the value with another value (e.g. replacing the string with a new one that has all illegals chars taken out). I have a 5,000 line test file. The upload, initial check, and import takes about 5-6 seconds. The detailed error check and insert into the Errors table takes about 5-8 seconds (this file has about 1200 errors in it). However, the "resets" part takes about 40-45 seconds for 750 fields that need to be reset. When I comment out the resets function (returning immediately without actually calling the UPDATE stored proc), the process is very fast. With the resets turned on, the pages take 50 seconds to return. My UPDATE stored proc is using some recommended code from http://sommarskog.se/dynamic_sql.html, whereby it uses CASE instead of dynamic SQL: UPDATE dbo.Records SET dbo.Records.file_ID = CASE @field_name WHEN 'file_ID' THEN @field_value ELSE file_ID END, . . (all 50 varchar field CASE statements here) . WHERE dbo.Records.record_ID = @record_ID Is there any way I can help my performance here. Can I somehow group all of these UPDATE calls into a single transaction? Should I be reworking the UPDATE query somehow? Or is it just sheer quantity of 750+ UPDATEs and things are just slow (it's a quad proc server with 8GB ram). Any suggestions appreciated.

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• WPF Binding when setting DataTemplate Programically

  - by Daniel

  Hello, I have my little designer tool (my program). On the left side I have TreeView and on the right site I have Accordion. When I select a node I want to dynamically build Accordion Items based on Properties from DataContext of selected node. Selecting nodes works fine, and when I use this sample code for testing it works also. XAML code: <layoutToolkit:Accordion x:Name="accPanel" SelectionMode="ZeroOrMore" SelectionSequence="Simultaneous"> <layoutToolkit:AccordionItem Header="Controller Info"> <StackPanel Orientation="Horizontal" DataContext="{Binding}"> <TextBlock Text="Content:" /> <TextBlock Text="{Binding Path=Name}" /> </StackPanel> </layoutToolkit:AccordionItem> </layoutToolkit:Accordion> C# code: private void treeSceneNode_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e) { if (e.NewValue != e.OldValue) { if (e.NewValue is SceneNode) { accPanel.DataContext = e.NewValue; //e.NewValue is a class that contains Name property } } } But the problem occurs when I'm trying to achive this using DateTemplate and dynamically build AccordingItem, the Binding is not working: <layoutToolkit:Accordion x:Name="accPanel" SelectionMode="ZeroOrMore" SelectionSequence="Simultaneous"> </layoutToolkit:Accordion> and DateTemplate in my ResourceDictionary <DataTemplate x:Key="dtSceneNodeContent"> <StackPanel Orientation="Horizontal" DataContext="{Binding}"> <TextBlock Text="Content:" /> <TextBlock Text="{Binding Path=Name}" /> </StackPanel> </DataTemplate> and C# code: private void treeSceneNode_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e) { if (e.NewValue != e.OldValue) { ResourceDictionary rd = new ResourceDictionary(); rd.Source = new Uri("/SilverGL.GUI;component/SilverGLDesignerResourceDictionary.xaml", UriKind.RelativeOrAbsolute); if (e.NewValue is SceneNode) { accPanel.DataContext = e.NewValue; AccordionItem accController = new AccordionItem(); accController.Header = "Controller Info"; accController.ContentTemplate = rd["dtSceneNodeContent"] as DataTemplate; accPanel.Items.Add(accController); } else { // Other type of node } } } I really need help with this issue. Thanks for any support. Daniel

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• how to create a system-wide independent universal counter object primarily for Database keys?

  - by andora

  I would like to create/use a system-wide independent universal 'counter object' that can be called via COM in a thread-safe manner. The counter object will be passed an ID to identify which counter to return, handle the counting, 'persist' the count (occasionally), have reasonable performance (as fast as possible) perhaps capable of 1000 counts per second or better (1mS) and be accessible cross-process/out-of-process. The current count status must be persisted between object restarts/shutdowns. The counter object is liklely to be a 'singleton' type object implemented in some form of free-threaded dictionary, containing maybe 10 counters (perhaps 50 max). The count needs to be monotonic and consistent, (ie: guaranteed unique sequential values). Each counter should have a few methods, like reset, inc, dec, set, clear, remove. As a luxury, I would like to have a variable-increment (ie: 'step by' value). To support thread-safefty, perhaps some sorm of critical-section or mutex call. It just needs to return a long/4byte signed integer. I really want something that can be called from anywhere, including VBScript, so I figure COM is my preferred solution. The primary use of this is for database keys. I am unable to use autoinc or guid type keys and have ruled out database-generated counting systems at this point. I've spent days researching this and I have really struggled to find a solution. The best I can find is a free-threaded dictionary object that can be instantiated using COM+ from Motobit - it seems to offer all the 'basics' and I guess I could create some form of wrapper for this. So, here are my questions: Does such a 'general purpose counter-object already exist? Can you direct me to it? (MS did do an IIS/ASP object called 'MSWC.Counter' but this isn't 'cross-process'/ out-of-process component and isn't thread-safe. (but if it was, it would do!) What is the best way of creating such a Component? (I'd prefer VB6 right-now, [don't ask!] but can do in VB.NET2005 if I had to). I don't have the skills/knowledge/tools to use anything else. I am desparate for a workable solution. I need specific guidance! If anybody can code something up for me I am prepared to pay for it.

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• mounting ext4 fs with block size of 65536

  - by seaquest

  I am doing some benchmarking on EXT4 performance on Compact Flash media. I have created an ext4 fs with block size of 65536. however I can not mount it on ubuntu-10.10-netbook-i386. (it is already mounting ext4 fs with 4096 bytes of block sizes) According to my readings on ext4 it should allow such big block sized fs. I want to hear your comments. root@ubuntu:~# mkfs.ext4 -b 65536 /dev/sda3 Warning: blocksize 65536 not usable on most systems. mke2fs 1.41.12 (17-May-2010) mkfs.ext4: 65536-byte blocks too big for system (max 4096) Proceed anyway? (y,n) y Warning: 65536-byte blocks too big for system (max 4096), forced to continue Filesystem label= OS type: Linux Block size=65536 (log=6) Fragment size=65536 (log=6) Stride=0 blocks, Stripe width=0 blocks 19968 inodes, 19830 blocks 991 blocks (5.00%) reserved for the super user First data block=0 1 block group 65528 blocks per group, 65528 fragments per group 19968 inodes per group Writing inode tables: done Creating journal (1024 blocks): done Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 37 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override. root@ubuntu:~# tune2fs -l /dev/sda3 tune2fs 1.41.12 (17-May-2010) Filesystem volume name: <none> Last mounted on: <not available> Filesystem UUID: 4cf3f507-e7b4-463c-be11-5b408097099b Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr resize_inode dir_index filetype extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize Filesystem flags: signed_directory_hash Default mount options: (none) Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 19968 Block count: 19830 Reserved block count: 991 Free blocks: 18720 Free inodes: 19957 First block: 0 Block size: 65536 Fragment size: 65536 Blocks per group: 65528 Fragments per group: 65528 Inodes per group: 19968 Inode blocks per group: 78 Flex block group size: 16 Filesystem created: Sat Feb 5 14:39:55 2011 Last mount time: n/a Last write time: Sat Feb 5 14:40:02 2011 Mount count: 0 Maximum mount count: 37 Last checked: Sat Feb 5 14:39:55 2011 Check interval: 15552000 (6 months) Next check after: Thu Aug 4 14:39:55 2011 Lifetime writes: 70 MB Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 28 Desired extra isize: 28 Journal inode: 8 Default directory hash: half_md4 Directory Hash Seed: afb5b570-9d47-4786-bad2-4aacb3b73516 Journal backup: inode blocks root@ubuntu:~# mount -t ext4 /dev/sda3 /mnt/ mount: wrong fs type, bad option, bad superblock on /dev/sda3, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so

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• Could not load file or assembly 'Base' or one of its dependencies. Access is denied

  - by starcorn

  I have deployed one web project into Azure emulator. And I get this error saying that Could not load file or assembly Base. The thing is that this web project, got dependencies to another project in the same solution. I have added that dependency into the reference list of my web project. And if I run this web application without using the azure emulator it will run fine. But I will get error when I try to run it on the azure emulator. At first glance I thought that I maybe need to add the other project as role also. But it couldn't be that. Anyone know what the problem might be? I hope I got enough data for you to look into. My solution structure looks like following Solution Base WebAPI WebAPI.Azure And it is the WebAPI that has a dependency to the Base project Here's the Assembly load trace WRN: Assembly binding logging is turned OFF. To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1. Note: There is some performance penalty associated with assembly bind failure logging. To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog]. And stack trace [FileLoadException: Could not load file or assembly 'Base' or one of its dependencies. Access is denied.] System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +0 System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection, Boolean suppressSecurityChecks) +567 System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +192 System.Reflection.Assembly.Load(String assemblyString) +35 System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +123 [ConfigurationErrorsException: Could not load file or assembly 'Base' or one of its dependencies. Access is denied.] System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +11568160 System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +485 System.Web.Configuration.AssemblyInfo.get_AssemblyInternal() +79 System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +337 System.Web.Compilation.BuildManager.CallPreStartInitMethods() +280 System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +1167 [HttpException (0x80004005): Could not load file or assembly 'Base' or one of its dependencies. Access is denied.] System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +11700896 System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +141 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4869125

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• In a PHP project, how do you organize and access your helper objects?

  - by Pekka

  How do you organize and manage your helper objects like the database engine, user notification, error handling and so on in a PHP based, object oriented project? Say I have a large PHP CMS. The CMS is organized in various classes. A few examples: the database object user management an API to create/modify/delete items a messaging object to display messages to the end user a context handler that takes you to the right page a navigation bar class that shows buttons a logging object possibly, custom error handling etc. I am dealing with the eternal question, how to best make these objects accessible to each part of the system that needs it. my first apporach, many years ago was to have a $application global that contained initialized instances of these classes. global $application; $application->messageHandler->addMessage("Item successfully inserted"); I then changed over to the Singleton pattern and a factory function: $mh =&factory("messageHandler"); $mh->addMessage("Item successfully inserted"); but I'm not happy with that either. Unit tests and encapsulation become more and more important to me, and in my understanding the logic behind globals/singletons destroys the basic idea of OOP. Then there is of course the possibility of giving each object a number of pointers to the helper objects it needs, probably the very cleanest, resource-saving and testing-friendly way but I have doubts about the maintainability of this in the long run. Most PHP frameworks I have looked into use either the singleton pattern, or functions that access the initialized objects. Both fine approaches, but as I said I'm happy with neither. I would like to broaden my horizon on what is possible here and what others have done. I am looking for examples, additional ideas and pointers towards resources that discuss this from a long-term, real-world perspective. Also, I'm interested to hear about specialized, niche or plain weird approaches to the issue. Bounty I am following the popular vote in awarding the bounty, the answer which is probably also going to give me the most. Thank you for all your answers!

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• Browser detection Plugin?

  - by chobo2

  Hi I have a website that I made and I am planning to redo it. The current version of the site used a jquery callout plugin that did not fully work in IE6. This got me thinking about browser detection. At first I was just going to put the supported browsers on the home page but then today on Digg I saw some post about some jquery plugins and wordpress and in the article there was a plugin for detecting IE. So I started to look around for some browser detection plugins. I found a few of them but they where over the top like this one sevenup Its nice but it makes a huge popup and tells them to update. This one is better then another one I found where they basically forced the user to update or they could not continue on the site. So I found this one jquery plugin This one is pretty nice since it looks at the major browsers and does detection on them too expect for chrome which I noticed triggers and an outdated browser with this plugin. So I started to look at the jquery documentation to see if they had a browser detection for chrome this is when I saw that they "Deprecated" and now recommend "Support". So now I am just confused like "Support" seems to be good and I read many posts on this site saying you should use it. But then it does not support stuff like .png detection that might have been useful to me since of that plugin(however I probably will not be using the plugin anymore since I think the author just gave up on it). Plus I don't know if this is something I am looking for at this time. Like I am guessing with "Support" you use it to detect something that is not supported and then do some alternative thing for that browser? For me I am more looking for something to tell the user "Hey look I tested this browser in the these versions of Firefox(3.5+), IE(8+), Opera(9.5+),Chrome(Something), Safari(Something). If your not using these versions you may not being seeing the site how it was intended" Of course I would try to have something shorter then that message but that the gyst. I am also assuming that the site would work in future versions of these browsers. I still check to see if my site works(they usually do) and is half decent in IE 6 but I won't spend hours fixing stuff that might be off in older browsers like IE 6. I won't test my site in older version of other browsers like firefox since I would think the user have to the sense to update so no point testing firefox 2.0 or whatever. So is there a plugin that fits this description? Or can "Support" do what I want? Thanks

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• Can this way of storing typed objects be improved?

  - by Pindatjuh

  This is an "can it be improved"-question. Topic: Storing typed objects in memory. Background information: I'm building a compiler for the x86-32 Windows platform for my language. My goal includes typed objects. Idea: Every primitive is a semi-class (it can be used as if it was a normal class, but it's stored more compact). Every class is represented by primitives and some meta-data (containing class-properties, inheritance stuff, etc.). The meta-data is complex: it doesn't use fields but instead context-switches. For primitives, the meta-data is very small, compared to a "real" class, which is alot bigger. This enables another idea that "primitives are objects", in my language, which I found nessecairy. Example: If I have an array of 32 booleans, then the pure content of this array is exactly 4 byte (32 bits of booleans). The meta-data will contain flags that the type is an array of booleans, which contains 32 entries. The meta-data is very compacted, on bit-level: using a sort of "packing" mechanism, which is read by a FSM at runtime, when doing inspection of the type (like when passing the object to methods for checking, etc.) For instance (read from left to right, top to bottom, remember vertical position when going to the right, and check nearest column header for meaning of switch): Primitive? Array? Type-Meta 1 Byte? || Size (1 byte) 1 1 [...] 1 [...] done 0 2 Bytes? || Size (2 bytes) 1 [...] done || Size (4 bytes) 0 [...] done Integer? 1 Byte? 2 Bytes? 0 1 0 1 done 1 done 0 done Boolean? Byte? 0 1 0 done 1 done More-Primitives 0 .... Class-Stuff (Huge) 0 ... (After reaching done the data is inserted. || = byte alignment. [...] is variable sized. ... is not described here, for simplicity. And let's call them cost-based-data-structures.) For an array of 32 booleans containing all true values, the memory for this type would be (read top-down): 1 Primitive 1 Array 1 ArrayType: Primitive 0 Not-Array 0 Not-Integer 1 Boolean 0 Not-Byte (thus bit) 1 Integer Size: 1 Byte 00100000 Array size 01010101 01010101 01010101 01010101 Data (user defined) Thus, 8 bytes represent 32 booleans in an array: 11100101 00100000 01010101 01010101 01010101 01010101 How can I improve this? (Both performance- and memory-consumption wise)

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• Java app makes screen display unresponsive after 10 minutes of user idle time

  - by Ross

  I've written a Java app that allows users to script mouse/keyboard input (JMacro, link not important, only for the curious). I personally use the application to automate character actions in an online game overnight while I sleep. Unfortunately, I keep coming back to the computer in the morning to find it unresponsive. Upon further testing, I'm finding that my application causes the computer to become unresponsive after about 10 minutes of user idle time (even if the application itself it simulating user activity). I can't seem to pin-point the issue, so I'm hoping somebody else might have a suggestion of where to look or what might be causing the issue. The relevant symptoms and characteristics: Unresponsiveness occurs after user is idle for 10 minutes User can still move the mouse pointer around the screen Everything but the mouse appears frozen... mouse clicks have no effect and no applications update their displays, including the Windows 7 desktop I left the task manager up along the with the app overnight so I could see the last task manager image before the screen freezes... the Java app is at normal CPU/Memory usage and total CPU usage is only ~1% After moving the mouse (in other words, the user comes back from being idle), the screen image starts updating again within 30 minutes (this is very hit and miss... sometimes 10 minutes, sometimes no results after two hours) User can CTRL-ALT-DEL to get to Windows 7's CTRL-ALT-DEL screen (after a 30 second pause). User is still able to move mouse pointer, but clicking any of the button options causes the screen to appear to freeze again On some very rare occasions, the system never freezes, and I come back to it in the morning with full responsiveness The Java app automatically stops input scripting in the middle of the night, so Windows 7 detects "real" idleness and turns the monitors into Standby mode... which they successfully come out of upon manually moving the mouse in the morning when I wake up, even though the desktop display still appears frozen Given the symptoms and characteristics of the issue, it's as if the Java app is causing the desktop display of the logged in user to stop updating, including any running applications. Programming concepts and Java packages used: Multi-threading Standard out and err are rerouted to a javax.swing.JTextArea The application uses a Swing GUI awt.Robot (very heavily used) awt.PointerInfo awt.MouseInfo System Specs: Windows 7 Professional Java 1.6.0 u17 In conclusion, I should stress that I'm not looking for any specific solutions, as I'm not asking a very specific question. I'm just wondering if anybody has run into a similar problem when using the Java libraries that I'm using. I would also gladly appreciate any suggestions for things to try to attempt to further pinpoint what is causing my problem. Thanks! Ross PS, I'll post an update/answer if I manage to stumble across anything else while I continue to debug this.

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• Usage of Document() function in XSLT 1.0

  - by infant programmer

  I am triggering the transformation using a .NET code, unless I add "EnableDocumentFunction" property to the XSL-Setting, the program throws error saying .. "Usage of Document() function is prohibited", Actually the program is not editable and a kind of read-only .. is it possible to edit the XSL code itself so that I can use document() function?? The sample XSL and XMLs are Here: Sample XML : <?xml version="1.0" encoding="utf-8"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl" > <xsl:output method="xml" indent="yes"/> <xsl:template match="@* | node()"> <xsl:copy> <xsl:apply-templates select="@* | node()"/> </xsl:copy> </xsl:template> <xsl:variable name="State_Code_Trn"> <State In="California" Out="CA"/> <State In="CA" Out="CA"/> <State In="Texas" Out="TX"/> <State In="TX" Out="TX"/> </xsl:variable> <xsl:template name="testing" match="test_node"> <xsl:variable name="test_val"> <xsl:value-of select="."/> </xsl:variable> <xsl:element name="{name()}"> <xsl:choose> <xsl:when test="document('')/*/xsl:variable[@name='State_Code_Trn'] /State[@In=$test_val]"> <xsl:value-of select="document('')/*/xsl:variable[@name='State_Code_Trn'] /State[@In=$test_val]/@Out"/> </xsl:when> <xsl:otherwise> <xsl:text>Other</xsl:text> </xsl:otherwise> </xsl:choose> </xsl:element> </xsl:template> </xsl:stylesheet> And the sample XML : <?xml version="1.0" encoding="utf-8"?> <root> <test_node>California</test_node> <test_node>CA</test_node> <test_node> CA</test_node> <test_node>Texas</test_node> <test_node>TX</test_node> <test_node>CAA</test_node> <test_node></test_node> </root>

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• Using jQuery to store basic text string in mySQL base?

  - by Kenny Bones

  Could someone point me in the right direction here? Basically, I've got this jQuery code snippet: $('.bggallery_images').click(function () { var newBG = "url('" + $(this).attr('src'); var fullpath = $(this).attr('src'); var filename = fullpath.replace('img/Bakgrunner/', ''); $('#wrapper').css('background-image', newBG); // Lagre til SQL $.ajax({ url: "save_to_db.php", // The url to your function to handle saving to the db data: filename, dataType: 'Text', type: 'POST', // Could also use GET if you prefer success: function (data) { // Just for testing purposes. alert('Background changed to: ' + data); } }); }); This is being run when I click a certain button. So it's actually within a click handler. If I understand this correctly, this snippet takes the source if the image I just clicked and strips it so I end up with only the filename. If I do an alert(filename), I get the filename only. So this is working ok. But then, it does an ajax call to a php file called "save_to_db.php" and sends data: filename. This is correct right? Then, it does a callback which does an alert + data. Does this seem correct so far? Cause my php file looks like this: <?php require("dbconnect2.php"); $uploadstring = $_POST['filename']; $sessionid = $_SESSION['id']; echo ($sessionid); mysql_query("UPDATE brukere SET brukerBakgrunn = '$uploadstring' WHERE brukerID=" .$_SESSION['id']); mysql_close(); ?> When I click the image, the jQuery snippet fires and I get the results of this php file as output for the alert box. I think that the variables somehow are empty. Because notice the echo($sessionid); which is a variable I've created just to test what the session ID is. And it returns nothing. What could be the issue here? Edit: I just tried to echo out the $uploadstring variable as well and it also returns nothing. It's like the jQuery snippet doesn't even pass the variable on to the php file?

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• UIScrollView Infinite Scrolling

  - by Ben Robinson

  I'm attempting to setup a scrollview with infinite (horizontal) scrolling. Scrolling forward is easy - I have implemented scrollViewDidScroll, and when the contentOffset gets near the end I make the scrollview contentsize bigger and add more data into the space (i'll have to deal with the crippling effect this will have later!) My problem is scrolling back - the plan is to see when I get near the beginning of the scroll view, then when I do make the contentsize bigger, move the existing content along, add the new data to the beginning and then - importantly adjust the contentOffset so the data under the view port stays the same. This works perfectly if I scroll slowly (or enable paging) but if I go fast (not even very fast!) it goes mad! Heres the code: - (void) scrollViewDidScroll:(UIScrollView *)scrollView { float pageNumber = scrollView.contentOffset.x / 320; float pageCount = scrollView.contentSize.width / 320; if (pageNumber > pageCount-4) { //Add 10 new pages to end mainScrollView.contentSize = CGSizeMake(mainScrollView.contentSize.width + 3200, mainScrollView.contentSize.height); //add new data here at (320*pageCount, 0); } //*** the problem is here - I use updatingScrollingContent to make sure its only called once (for accurate testing!) if (pageNumber < 4 && !updatingScrollingContent) { updatingScrollingContent = YES; mainScrollView.contentSize = CGSizeMake(mainScrollView.contentSize.width + 3200, mainScrollView.contentSize.height); mainScrollView.contentOffset = CGPointMake(mainScrollView.contentOffset.x + 3200, 0); for (UIView *view in [mainContainerView subviews]) { view.frame = CGRectMake(view.frame.origin.x+3200, view.frame.origin.y, view.frame.size.width, view.frame.size.height); } //add new data here at (0, 0); } //** MY CHECK! NSLog(@"%f", mainScrollView.contentOffset.x); } As the scrolling happens the log reads: 1286.500000 1285.500000 1284.500000 1283.500000 1282.500000 1281.500000 1280.500000 Then, when pageNumber<4 (we're getting near the beginning): 4479.500000 4479.500000 Great! - but the numbers should continue to go down in the 4,000s but the next log entries read: 1278.000000 1277.000000 1276.500000 1275.500000 etc.... Continiuing from where it left off! Just for the record, if scrolled slowly the log reads: 1294.500000 1290.000000 1284.500000 1280.500000 4476.000000 4476.000000 4473.000000 4470.000000 4467.500000 4464.000000 4460.500000 4457.500000 etc.... Any ideas???? Thanks Ben.

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• multithreading with database

  - by Darsin

  I am looking out for a strategy to utilize multithreading (probably asynchronous delegates) to do a synchronous operation. I am new to multithreading so i will outline my scenario first. This synchronous operation right now is done for one set of data (portfolio) based on the the parameters provided. The (psudeo-code) implementation is given below: public DataSet DoTests(int fundId, DateTime portfolioDate) { // Get test results for the portfolio // Call the database adapter method, which in turn is a stored procedure, // which in turns runs a series of "rule" stored procs and fills a local temp table and returns it back. DataSet resultsDataSet = GetTestResults(fundId, portfolioDate); try { // Do some local processing on the results DoSomeProcessing(resultsDataSet); // Save the results in Test, TestResults and TestAllocations tables in a transaction. // Sets a global transaction which is provided to all the adapter methods called below // It is defined in the Base class StartTransaction("TestTransaction"); // Save Test and get a testId int testId = UpdateTest(resultsDataSet); // Adapter method, uses the same transaction // Update testId in the other tables in the dataset UpdateTestId(resultsDataSet, testId); // Update TestResults UpdateTestResults(resultsDataSet); // Adapter method, uses the same transaction // Update TestAllocations UpdateTestAllocations(resultsDataSet); // Adapter method, uses the same transaction // It is defined in the base class CommitTransaction("TestTransaction"); } catch { RollbackTransaction("TestTransaction"); } return resultsDataSet; } Now the requirement is to do it for multiple set of data. One way would be to call the above DoTests() method in a loop and get the data. I would prefer doing it in parallel. But there are certain catches: StartTransaction() method creates a connection (and transaction) every time it is called. All the underlying database tables, procedures are the same for each call of DoTests(). (obviously). Thus my question are: Will using multithreading anyway improve performance? What are the chances of deadlock especially when new TestId's are being created and the Tests, TestResults and TestAllocations are being saved? How can these deadlocked be handled? Is there any other more efficient way of doing the above operation apart from looping over the DoTests() method repeatedly?

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• QTreeView memory consumption

  - by Eye of Hell

  Hello. I'm testing QTreeView functionality right now, and i was amazed by one thing. It seems that QTreeView memory consumption depends on items count O_O. This is highly unusual, since model-view containers of such type only keeps track for items being displayed, and rest of items are in the model. I have written a following code with a simple model that holds no data and just reports that it has 10 millions items. With MFC, Windows API or .NET tree / list with such model will take no memory, since it will display only 10-20 visible elements and will request model for more upon scrolling / expanding items. But with Qt, such simple model results in ~300Mb memory consumtion. Increasing number of items will increase memory consumption. Maybe anyone can hint me what i'm doing wrong? :) #include <QtGui/QApplication> #include <QTreeView> #include <QAbstractItemModel> class CModel : public QAbstractItemModel { public: QModelIndex index ( int i_nRow, int i_nCol, const QModelIndex& i_oParent = QModelIndex() ) const { return createIndex( i_nRow, i_nCol, 0 ); } public: QModelIndex parent ( const QModelIndex& i_oInex ) const { return QModelIndex(); } public: int rowCount ( const QModelIndex& i_oParent = QModelIndex() ) const { return i_oParent.isValid() ? 0 : 1000 * 1000 * 10; } public: int columnCount ( const QModelIndex& i_oParent = QModelIndex() ) const { return 1; } public: QVariant data ( const QModelIndex& i_oIndex, int i_nRole = Qt::DisplayRole ) const { return Qt::DisplayRole == i_nRole ? QVariant( "1" ) : QVariant(); } }; int main(int argc, char *argv[]) { QApplication a(argc, argv); QTreeView oWnd; CModel oModel; oWnd.setUniformRowHeights( true ); oWnd.setModel( & oModel ); oWnd.show(); return a.exec(); }

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• Implementing a logging library in .NET with a database as the storage medium

  - by Dave

  I'm just starting to work on a logging library that everyone can use to keep track of any sort of system information while the user is running our application. The simplest example so far is to track Info, Warnings, and Errors. I want all plugins to be able to use this feature, but since each developer might have a different idea of what's important to report, I want to keep this as generic as possible. In the C++ world, I would normally use something like a stl::pair<string,string> to act as a key value pair structure, and have a stl::list of these to act as a "row" in the log. The log cache would then be a list<list<pair<string,string>>> (ugh!). This way, the developers can use a const string key like INFO, WARNING, ERROR to have a consistent naming for a column in the database (for SELECTing specific types of information). I'd like the database to be able to deal with any number of distinct column names. For example, John might have an INFO row with a column called USER, and Bill might have an INFO row with a column called FILENAME. I want the log viewer to be able to display all information, and if one report doesn't have a value for INFO / FILENAME, those fields should just appear blank. So one option is to use List<List<KeyValuePair<String,String>>, and the another is to have the log library consumer somehow "register" its schema, and then have the database do an ALTER TABLE to handle this situation. Yet another idea is to have a table that's just for key value pairs, with a foreign key that maps the key value pairs back to the original log entry. I obviously don't want logging to bog down the system, so I only lock the log cache to make a copy of the data (and remove the already-copied data), then a background thread will dump the information to the database. My specific questions regarding this are: Do you see any performance issues? In other words, have you ever tried something like this and found that certain things just don't work well in practice? Is there a more .NETish way to implement the key value pairs, other than List<List<KeyValuePair<String,String>>>? Even if there is a way to do #2 better, is the ALTER TABLE idea I proposed above a Bad Thing? Would you recommend multiple databases over a single one? I don't yet have an idea of how frequently the log would get written to, but we ideally would like to have lots of low level information. Perhaps there should be a DB with a fixed schema only for the low level stuff, and then another DB that's more flexible for reporting information back to users.

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• iPhone Gps logging inaccurate

  - by Martijn

  I'm logging gps points during a walk. Below it shows the function that the coordinates are saved each 5 seconds. i Did several tests but i cannot get the right accuracy i want. (When testing the sky is clear also tests in google maps shows me that the gps signal is good). here is the code: -(void)viewDidAppear:(BOOL)animated{ if (self.locationManager == nil){ self.locationManager = [[[CLLocationManager alloc] init] autorelease]; locationManager.delegate = self; // only notify under 100 m accuracy locationManager.distanceFilter = 100.0f; locationManager.desiredAccuracy= kCLLocationAccuracyBest; [locationManager startUpdatingLocation]; } } - start logging [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(getData) userInfo:nil repeats:YES]; </code> <code> -(void)getData{ int distance; // re-use location. if ([ [NSString stringWithFormat:@"%1.2f",previousLat] isEqualToString:@"0.00"]){ // if previous location is not available, do nothing distance = 0; }else{ CLLocation *loc1 = [[CLLocation alloc] initWithLatitude:previousLat longitude:previousLong]; CLLocation *loc2 = [[CLLocation alloc] initWithLatitude:latGlobal longitude:longGlobal]; distance = [loc1 getDistanceFrom: loc2]; } // overwrite latGlobal with new variable previousLat = latGlobal; previousLong = longGlobal; // store location and save data to database // this part goes ok } - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation { // track the time to get a new gps result (for gps indicator orb) lastPointTimestamp = [newLocation.timestamp copy]; // test that the horizontal accuracy does not indicate an invalid measurement if (newLocation.horizontalAccuracy < 0) return; // test the age of the location measurement to determine if the measurement is cached // don't rely on cached measurements NSTimeInterval locationAge = -[newLocation.timestamp timeIntervalSinceNow]; if (locationAge > 5.0) return; latGlobal = fabs(newLocation.coordinate.latitude); longGlobal= fabs(newLocation.coordinate.longitude); } I have taken a screenshot of the plot results (the walk takes 30 minutes) and an example of what i'am trying to acomplish: http://www.flickr.com/photos/21258341@N07/4623969014/ i really hope someone can put me in the right direction.

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• Performing full screen grab in windows

  - by Steven Lu

  I am working an idea that involves getting a full capture of the screen including windows and apps, analyzing it, and then drawing items back onto the screen, as an overlay. I want to learn image processing techniques and I could get lots of data to work with if I can directly access the Windows screen. I could use this to build automation tools the likes of which have never been seen before. More on that later. I have full screen capture working for the most part. HWND hwind = GetDesktopWindow(); HDC hdc = GetDC(hwind); int resx = GetSystemMetrics(SM_CXSCREEN); int resy = GetSystemMetrics(SM_CYSCREEN); int BitsPerPixel = GetDeviceCaps(hdc,BITSPIXEL); HDC hdc2 = CreateCompatibleDC(hdc); BITMAPINFO info; info.bmiHeader.biSize = sizeof(BITMAPINFOHEADER); info.bmiHeader.biWidth = resx; info.bmiHeader.biHeight = resy; info.bmiHeader.biPlanes = 1; info.bmiHeader.biBitCount = BitsPerPixel; info.bmiHeader.biCompression = BI_RGB; void *data; hbitmap = CreateDIBSection(hdc2,&info,DIB_RGB_COLORS,(void**)&data,0,0); SelectObject(hdc2,hbitmap); Once this is done, I can call this repeatedly: BitBlt(hdc2,0,0,resx,resy,hdc,0,0,SRCCOPY); The cleanup code (I have no idea if this is correct): DeleteObject(hbitmap); ReleaseDC(hwind,hdc); if (hdc2) { DeleteDC(hdc2); } Every time BitBlt is called it grabs the screen and saves it in memory I can access thru data. Performance is somewhat satisfactory. BitBlt executes in 50 milliseconds (sometimes as low as 33ms) at 1920x1200x32. What surprises me is that when I switch display mode to 16 bit, 1920x1200x16, either through my graphics settings beforehand, or by using ChangeDisplaySettings, I get a massively improved screen grab time between 1ms and 2ms, which cannot be explained by the factor of two reduction in bit-depth. Using CreateDIBSection (as above) offers a significant speed up when in 16-bit mode, compared to if I set up with CreateCompatibleBitmap (6-7ms/f). Does anybody know why dropping to 16bit causes such a speed increase? Is there any hope for me to grab 32bit at such speeds? if not for the color depth, but for not forcing a change of screen buffer modes and the awful flickering.

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