Search Results

Search found 3642 results on 146 pages for 'architectural patterns'.

Page 43/146 | < Previous Page | 39 40 41 42 43 44 45 46 47 48 49 50  | Next Page >

• Design advice for avoiding change in several classes

  - by Anders Svensson

  Hi, I'm trying to figure out how to design a small application more elegantly, and make it more resistant to change. Basically it is a sort of project price calculator, and the problem is that there are many parameters that can affect the pricing. I'm trying to avoid cluttering the code with a lot of if-clauses for each parameter, but still I have e.g. if-clauses in two places checking for the value of the size parameter. I have the Head First Design Patterns book, and have tried to find ideas there, but the closest I got was the decorator pattern, which has an example where starbuzz coffee sets prices depending first on condiments added, and then later in an exercise by adding a size parameter (Tall, Grande, Venti). But that didn't seem to help, because adding that parameter still seemed to add if-clause complexity in a lot of places (and this being an exercise they didn't explain that further). What I am trying to avoid is having to change several classes if a parameter were to change or a new parameter added, or at least change in as few places as possible (there's some fancy design principle word for this that I don't rememeber :-)). Here below is the code. Basically it calculates the price for a project that has the tasks "Writing" and "Analysis" with a size parameter and different pricing models. There will be other parameters coming in later too, like "How new is the product?" (New, 1-5 years old, 6-10 years old), etc. Any advice on the best design would be greatly appreciated, whether a "design pattern" or just good object oriented principles that would make it resistant to change (e.g. adding another size, or changing one of the size values, and only have to change in one place rather than in several if-clauses): public class Project { private readonly int _numberOfProducts; protected Size _size; public Task Analysis { get; set; } public Task Writing { get; set; } public Project(int numberOfProducts) { _numberOfProducts = numberOfProducts; _size = GetSize(); Analysis = new AnalysisTask(numberOfProducts, _size); Writing = new WritingTask(numberOfProducts, _size); } private Size GetSize() { if (_numberOfProducts <= 2) return Size.small; if (_numberOfProducts <= 8) return Size.medium; return Size.large; } public double GetPrice() { return Analysis.GetPrice() + Writing.GetPrice(); } } public abstract class Task { protected readonly int _numberOfProducts; protected Size _size; protected double _pricePerHour; protected Dictionary<Size, int> _hours; public abstract int TotalHours { get; } public double Price { get; set; } protected Task(int numberOfProducts, Size size) { _numberOfProducts = numberOfProducts; _size = size; } public double GetPrice() { return _pricePerHour * TotalHours; } } public class AnalysisTask : Task { public AnalysisTask(int numberOfProducts, Size size) : base(numberOfProducts, size) { _pricePerHour = 850; _hours = new Dictionary<Size, int>() { { Size.small, 56 }, { Size.medium, 104 }, { Size.large, 200 } }; } public override int TotalHours { get { return _hours[_size]; } } } public class WritingTask : Task { public WritingTask(int numberOfProducts, Size size) : base(numberOfProducts, size) { _pricePerHour = 650; _hours = new Dictionary<Size, int>() { { Size.small, 125 }, { Size.medium, 100 }, { Size.large, 60 } }; } public override int TotalHours { get { if (_size == Size.small) return _hours[_size] * _numberOfProducts; if (_size == Size.medium) return (_hours[Size.small] * 2) + (_hours[Size.medium] * (_numberOfProducts - 2)); return (_hours[Size.small] * 2) + (_hours[Size.medium] * (8 - 2)) + (_hours[Size.large] * (_numberOfProducts - 8)); } } } public enum Size { small, medium, large } public partial class Form1 : Form { public Form1() { InitializeComponent(); List<int> quantities = new List<int>(); for (int i = 0; i < 100; i++) { quantities.Add(i); } comboBoxNumberOfProducts.DataSource = quantities; } private void comboBoxNumberOfProducts_SelectedIndexChanged(object sender, EventArgs e) { Project project = new Project((int)comboBoxNumberOfProducts.SelectedItem); labelPrice.Text = project.GetPrice().ToString(); labelWriterHours.Text = project.Writing.TotalHours.ToString(); labelAnalysisHours.Text = project.Analysis.TotalHours.ToString(); } } At the end is a simple current calling code in the change event for a combobox that set size... (BTW, I don't like the fact that I have to use several dots to get to the TotalHours at the end here either, as far as I can recall, that violates the "principle of least knowledge" or "the law of demeter", so input on that would be appreciated too, but it's not the main point of the question) Regards, Anders

  Read the article

• Windows Azure Service Bus Splitter and Aggregator

  - by Alan Smith

  This article will cover basic implementations of the Splitter and Aggregator patterns using the Windows Azure Service Bus. The content will be included in the next release of the “Windows Azure Service Bus Developer Guide”, along with some other patterns I am working on. I’ve taken the pattern descriptions from the book “Enterprise Integration Patterns” by Gregor Hohpe. I bought a copy of the book in 2004, and recently dusted it off when I started to look at implementing the patterns on the Windows Azure Service Bus. Gregor has also presented an session in 2011 “Enterprise Integration Patterns: Past, Present and Future” which is well worth a look. I’ll be covering more patterns in the coming weeks, I’m currently working on Wire-Tap and Scatter-Gather. There will no doubt be a section on implementing these patterns in my “SOA, Connectivity and Integration using the Windows Azure Service Bus” course. There are a number of scenarios where a message needs to be divided into a number of sub messages, and also where a number of sub messages need to be combined to form one message. The splitter and aggregator patterns provide a definition of how this can be achieved. This section will focus on the implementation of basic splitter and aggregator patens using the Windows Azure Service Bus direct programming model. In BizTalk Server receive pipelines are typically used to implement the splitter patterns, with sequential convoy orchestrations often used to aggregate messages. In the current release of the Service Bus, there is no functionality in the direct programming model that implements these patterns, so it is up to the developer to implement them in the applications that send and receive messages. Splitter A message splitter takes a message and spits the message into a number of sub messages. As there are different scenarios for how a message can be split into sub messages, message splitters are implemented using different algorithms. The Enterprise Integration Patterns book describes the splatter pattern as follows: How can we process a message if it contains multiple elements, each of which may have to be processed in a different way? Use a Splitter to break out the composite message into a series of individual messages, each containing data related to one item. The Enterprise Integration Patterns website provides a description of the Splitter pattern here. In some scenarios a batch message could be split into the sub messages that are contained in the batch. The splitting of a message could be based on the message type of sub-message, or the trading partner that the sub message is to be sent to. Aggregator An aggregator takes a stream or related messages and combines them together to form one message. The Enterprise Integration Patterns book describes the aggregator pattern as follows: How do we combine the results of individual, but related messages so that they can be processed as a whole? Use a stateful filter, an Aggregator, to collect and store individual messages until a complete set of related messages has been received. Then, the Aggregator publishes a single message distilled from the individual messages. The Enterprise Integration Patterns website provides a description of the Aggregator pattern here. A common example of the need for an aggregator is in scenarios where a stream of messages needs to be combined into a daily batch to be sent to a legacy line-of-business application. The BizTalk Server EDI functionality provides support for batching messages in this way using a sequential convoy orchestration. Scenario The scenario for this implementation of the splitter and aggregator patterns is the sending and receiving of large messages using a Service Bus queue. In the current release, the Windows Azure Service Bus currently supports a maximum message size of 256 KB, with a maximum header size of 64 KB. This leaves a safe maximum body size of 192 KB. The BrokeredMessage class will support messages larger than 256 KB; in fact the Size property is of type long, implying that very large messages may be supported at some point in the future. The 256 KB size restriction is set in the service bus components that are deployed in the Windows Azure data centers. One of the ways of working around this size restriction is to split large messages into a sequence of smaller sub messages in the sending application, send them via a queue, and then reassemble them in the receiving application. This scenario will be used to demonstrate the pattern implementations. Implementation The splitter and aggregator will be used to provide functionality to send and receive large messages over the Windows Azure Service Bus. In order to make the implementations generic and reusable they will be implemented as a class library. The splitter will be implemented in the LargeMessageSender class and the aggregator in the LargeMessageReceiver class. A class diagram showing the two classes is shown below. Implementing the Splitter The splitter will take a large brokered message, and split the messages into a sequence of smaller sub-messages that can be transmitted over the service bus messaging entities. The LargeMessageSender class provides a Send method that takes a large brokered message as a parameter. The implementation of the class is shown below; console output has been added to provide details of the splitting operation. public class LargeMessageSender {     private static int SubMessageBodySize = 192 * 1024;     private QueueClient m_QueueClient;       public LargeMessageSender(QueueClient queueClient)     {         m_QueueClient = queueClient;     }       public void Send(BrokeredMessage message)     {         // Calculate the number of sub messages required.         long messageBodySize = message.Size;         int nrSubMessages = (int)(messageBodySize / SubMessageBodySize);         if (messageBodySize % SubMessageBodySize != 0)         {             nrSubMessages++;         }           // Create a unique session Id.         string sessionId = Guid.NewGuid().ToString();         Console.WriteLine("Message session Id: " + sessionId);         Console.Write("Sending {0} sub-messages", nrSubMessages);           Stream bodyStream = message.GetBody<Stream>();         for (int streamOffest = 0; streamOffest < messageBodySize;             streamOffest += SubMessageBodySize)         {                                     // Get the stream chunk from the large message             long arraySize = (messageBodySize - streamOffest) > SubMessageBodySize                 ? SubMessageBodySize : messageBodySize - streamOffest;             byte[] subMessageBytes = new byte[arraySize];             int result = bodyStream.Read(subMessageBytes, 0, (int)arraySize);             MemoryStream subMessageStream = new MemoryStream(subMessageBytes);               // Create a new message             BrokeredMessage subMessage = new BrokeredMessage(subMessageStream, true);             subMessage.SessionId = sessionId;               // Send the message             m_QueueClient.Send(subMessage);             Console.Write(".");         }         Console.WriteLine("Done!");     }} The LargeMessageSender class is initialized with a QueueClient that is created by the sending application. When the large message is sent, the number of sub messages is calculated based on the size of the body of the large message. A unique session Id is created to allow the sub messages to be sent as a message session, this session Id will be used for correlation in the aggregator. A for loop in then used to create the sequence of sub messages by creating chunks of data from the stream of the large message. The sub messages are then sent to the queue using the QueueClient. As sessions are used to correlate the messages, the queue used for message exchange must be created with the RequiresSession property set to true. Implementing the Aggregator The aggregator will receive the sub messages in the message session that was created by the splitter, and combine them to form a single, large message. The aggregator is implemented in the LargeMessageReceiver class, with a Receive method that returns a BrokeredMessage. The implementation of the class is shown below; console output has been added to provide details of the splitting operation.   public class LargeMessageReceiver {     private QueueClient m_QueueClient;       public LargeMessageReceiver(QueueClient queueClient)     {         m_QueueClient = queueClient;     }       public BrokeredMessage Receive()     {         // Create a memory stream to store the large message body.         MemoryStream largeMessageStream = new MemoryStream();           // Accept a message session from the queue.         MessageSession session = m_QueueClient.AcceptMessageSession();         Console.WriteLine("Message session Id: " + session.SessionId);         Console.Write("Receiving sub messages");           while (true)         {             // Receive a sub message             BrokeredMessage subMessage = session.Receive(TimeSpan.FromSeconds(5));               if (subMessage != null)             {                 // Copy the sub message body to the large message stream.                 Stream subMessageStream = subMessage.GetBody<Stream>();                 subMessageStream.CopyTo(largeMessageStream);                   // Mark the message as complete.                 subMessage.Complete();                 Console.Write(".");             }             else             {                 // The last message in the sequence is our completeness criteria.                 Console.WriteLine("Done!");                 break;             }         }                     // Create an aggregated message from the large message stream.         BrokeredMessage largeMessage = new BrokeredMessage(largeMessageStream, true);         return largeMessage;     } }   The LargeMessageReceiver initialized using a QueueClient that is created by the receiving application. The receive method creates a memory stream that will be used to aggregate the large message body. The AcceptMessageSession method on the QueueClient is then called, which will wait for the first message in a message session to become available on the queue. As the AcceptMessageSession can throw a timeout exception if no message is available on the queue after 60 seconds, a real-world implementation should handle this accordingly. Once the message session as accepted, the sub messages in the session are received, and their message body streams copied to the memory stream. Once all the messages have been received, the memory stream is used to create a large message, that is then returned to the receiving application. Testing the Implementation The splitter and aggregator are tested by creating a message sender and message receiver application. The payload for the large message will be one of the webcast video files from http://www.cloudcasts.net/, the file size is 9,697 KB, well over the 256 KB threshold imposed by the Service Bus. As the splitter and aggregator are implemented in a separate class library, the code used in the sender and receiver console is fairly basic. The implementation of the main method of the sending application is shown below.   static void Main(string[] args) {     // Create a token provider with the relevant credentials.     TokenProvider credentials =         TokenProvider.CreateSharedSecretTokenProvider         (AccountDetails.Name, AccountDetails.Key);       // Create a URI for the serivce bus.     Uri serviceBusUri = ServiceBusEnvironment.CreateServiceUri         ("sb", AccountDetails.Namespace, string.Empty);       // Create the MessagingFactory     MessagingFactory factory = MessagingFactory.Create(serviceBusUri, credentials);       // Use the MessagingFactory to create a queue client     QueueClient queueClient = factory.CreateQueueClient(AccountDetails.QueueName);       // Open the input file.     FileStream fileStream = new FileStream(AccountDetails.TestFile, FileMode.Open);       // Create a BrokeredMessage for the file.     BrokeredMessage largeMessage = new BrokeredMessage(fileStream, true);       Console.WriteLine("Sending: " + AccountDetails.TestFile);     Console.WriteLine("Message body size: " + largeMessage.Size);     Console.WriteLine();         // Send the message with a LargeMessageSender     LargeMessageSender sender = new LargeMessageSender(queueClient);     sender.Send(largeMessage);       // Close the messaging facory.     factory.Close();  } The implementation of the main method of the receiving application is shown below. static void Main(string[] args) {       // Create a token provider with the relevant credentials.     TokenProvider credentials =         TokenProvider.CreateSharedSecretTokenProvider         (AccountDetails.Name, AccountDetails.Key);       // Create a URI for the serivce bus.     Uri serviceBusUri = ServiceBusEnvironment.CreateServiceUri         ("sb", AccountDetails.Namespace, string.Empty);       // Create the MessagingFactory     MessagingFactory factory = MessagingFactory.Create(serviceBusUri, credentials);       // Use the MessagingFactory to create a queue client     QueueClient queueClient = factory.CreateQueueClient(AccountDetails.QueueName);       // Create a LargeMessageReceiver and receive the message.     LargeMessageReceiver receiver = new LargeMessageReceiver(queueClient);     BrokeredMessage largeMessage = receiver.Receive();       Console.WriteLine("Received message");     Console.WriteLine("Message body size: " + largeMessage.Size);       string testFile = AccountDetails.TestFile.Replace(@"\In\", @"\Out\");     Console.WriteLine("Saving file: " + testFile);       // Save the message body as a file.     Stream largeMessageStream = largeMessage.GetBody<Stream>();     largeMessageStream.Seek(0, SeekOrigin.Begin);     FileStream fileOut = new FileStream(testFile, FileMode.Create);     largeMessageStream.CopyTo(fileOut);     fileOut.Close();       Console.WriteLine("Done!"); } In order to test the application, the sending application is executed, which will use the LargeMessageSender class to split the message and place it on the queue. The output of the sender console is shown below. The console shows that the body size of the large message was 9,929,365 bytes, and the message was sent as a sequence of 51 sub messages. When the receiving application is executed the results are shown below. The console application shows that the aggregator has received the 51 messages from the message sequence that was creating in the sending application. The messages have been aggregated to form a massage with a body of 9,929,365 bytes, which is the same as the original large message. The message body is then saved as a file. Improvements to the Implementation The splitter and aggregator patterns in this implementation were created in order to show the usage of the patterns in a demo, which they do quite well. When implementing these patterns in a real-world scenario there are a number of improvements that could be made to the design. Copying Message Header Properties When sending a large message using these classes, it would be great if the message header properties in the message that was received were copied from the message that was sent. The sending application may well add information to the message context that will be required in the receiving application. When the sub messages are created in the splitter, the header properties in the first message could be set to the values in the original large message. The aggregator could then used the values from this first sub message to set the properties in the message header of the large message during the aggregation process. Using Asynchronous Methods The current implementation uses the synchronous send and receive methods of the QueueClient class. It would be much more performant to use the asynchronous methods, however doing so may well affect the sequence in which the sub messages are enqueued, which would require the implementation of a resequencer in the aggregator to restore the correct message sequence. Handling Exceptions In order to keep the code readable no exception handling was added to the implementations. In a real-world scenario exceptions should be handled accordingly.

  Read the article

• Going back to ASP.Net Webforms from ASP.Net MVC. Recommend patterns/architectures?

  - by jlnorsworthy

  To many of you this will sound like a ridiculous question, but I am asking because I have little to no experience with ASP.Net Webforms - I went straight to ASP.Net MVC. I am now working on a project where we are limited to .Net 2.0 and Visual Studio 2005. I liked the clean separation of concerns when working with ASP.Net MVC, and am looking for something to make webforms less unbearable. Are there any recommended patterns or practices for people who prefer asp.net MVC, but are stuck on .net 2.0 and visual studio 2005?

  Read the article

• Recommended book on Actors concurrency model (patterns, pitfalls, etc.)?

  - by Larry OBrien

  The Actors concurrency model is clearly gaining favor. Is there a good book that presents the patterns and pitfalls of the model? I am thinking about something that would discuss, for instance, the problems of consistency and correctness in the context of hundreds or thousands of independent Actors. It would be okay if it were associated with a specific language (erlang, I would imagine, since that seems universally regarded as the proven implementation of Actors), but I am hoping for something more than an introductory chapter or two. (FWIW, I'm actually most interested in Actors as they are implemented in Scala.)

  Read the article

• Activation Error while testing Exception Handling Application Block

  - by CletusLoomis

  I'm getting the following error while testing my EHAB implementation: {"Activation error occured while trying to get instance of type ExceptionPolicyImpl, key "LogPolicy""} System.Exception Stack Trace: StackTrace " at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance(Type serviceType, String key) in c:\Home\Chris\Projects\CommonServiceLocator\main\Microsoft.Practices.ServiceLocation\ServiceLocatorImplBase.cs:line 53 at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance[TService](String key) in c:\Home\Chris\Projects\CommonServiceLocator\main\Microsoft.Practices.ServiceLocation\ServiceLocatorImplBase.cs:line 103 at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.GetExceptionPolicy(Exception exception, String policyName) in e:\Builds\EntLib\Latest\Source\Blocks\ExceptionHandling\Src\ExceptionHandling\ExceptionPolicy.cs:line 131 at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.HandleException(Exception exceptionToHandle, String policyName) in e:\Builds\EntLib\Latest\Source\Blocks\ExceptionHandling\Src\ExceptionHandling\ExceptionPolicy.cs:line 55 at Blackbox.Exception.ExceptionMain.LogException(Exception pException) in C:_Work_Black Box\Blackbox.Exception\ExceptionMain.vb:line 14 at BlackBox.Business.BusinessMain.TestExceptionHandling() in C:_Work_Black Box\BlackBox.Business\BusinessMain.vb:line 16 at Blackbox.Service.Service1.TestExceptionHandling() in C:_Work_Black Box\Blackbox.Service\Service.svc.vb:line 43" String Inner Exception: InnerException {"Resolution of the dependency failed, type = "Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyImpl", name = "LogPolicy". Exception occurred while: Calling constructor Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FormattedEventLogTraceListener(System.String source, System.String log, System.String machineName, Microsoft.Practices.EnterpriseLibrary.Logging.Formatters.ILogFormatter formatter). Exception is: ArgumentException - Event log names must consist of printable characters and cannot contain \, *, ?, or spaces At the time of the exception, the container was: Resolving Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyImpl,LogPolicy Resolving parameter "policyEntries" of constructor Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyImpl(System.String policyName, System.Collections.Generic.IEnumerable1[[Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyEntry, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]] policyEntries) Resolving Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyEntry,LogPolicy.All Exceptions Resolving parameter "handlers" of constructor Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyEntry(System.Type exceptionType, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.PostHandlingAction postHandlingAction, System.Collections.Generic.IEnumerable1[[Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.IExceptionHandler, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]] handlers, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Instrumentation.IExceptionHandlingInstrumentationProvider instrumentationProvider) Resolving Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging.LoggingExceptionHandler,LogPolicy.All Exceptions.Logging Exception Handler (mapped from Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.IExceptionHandler, LogPolicy.All Exceptions.Logging Exception Handler) Resolving parameter "writer" of constructor Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging.LoggingExceptionHandler(System.String logCategory, System.Int32 eventId, System.Diagnostics.TraceEventType severity, System.String title, System.Int32 priority, System.Type formatterType, Microsoft.Practices.EnterpriseLibrary.Logging.LogWriter writer) Resolving Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterImpl,LogWriter.default (mapped from Microsoft.Practices.EnterpriseLibrary.Logging.LogWriter, (none)) Resolving parameter "structureHolder" of constructor Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterImpl(Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterStructureHolder structureHolder, Microsoft.Practices.EnterpriseLibrary.Logging.Instrumentation.ILoggingInstrumentationProvider instrumentationProvider, Microsoft.Practices.EnterpriseLibrary.Logging.ILoggingUpdateCoordinator updateCoordinator) Resolving Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterStructureHolder,LogWriterStructureHolder.default (mapped from Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterStructureHolder, (none)) Resolving parameter "traceSources" of constructor Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterStructureHolder(System.Collections.Generic.IEnumerable1[[Microsoft.Practices.EnterpriseLibrary.Logging.Filters.ILogFilter, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]] filters, System.Collections.Generic.IEnumerable1[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] traceSourceNames, System.Collections.Generic.IEnumerable1[[Microsoft.Practices.EnterpriseLibrary.Logging.LogSource, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]] traceSources, Microsoft.Practices.EnterpriseLibrary.Logging.LogSource allEventsTraceSource, Microsoft.Practices.EnterpriseLibrary.Logging.LogSource notProcessedTraceSource, Microsoft.Practices.EnterpriseLibrary.Logging.LogSource errorsTraceSource, System.String defaultCategory, System.Boolean tracingEnabled, System.Boolean logWarningsWhenNoCategoriesMatch, System.Boolean revertImpersonation) Resolving Microsoft.Practices.EnterpriseLibrary.Logging.LogSource,General Resolving parameter "traceListeners" of constructor Microsoft.Practices.EnterpriseLibrary.Logging.LogSource(System.String name, System.Collections.Generic.IEnumerable1[[System.Diagnostics.TraceListener, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] traceListeners, System.Diagnostics.SourceLevels level, System.Boolean autoFlush, Microsoft.Practices.EnterpriseLibrary.Logging.Instrumentation.ILoggingInstrumentationProvider instrumentationProvider) Resolving Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.ReconfigurableTraceListenerWrapper,Event Log Listener (mapped from System.Diagnostics.TraceListener, Event Log Listener) Resolving parameter "wrappedTraceListener" of constructor Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.ReconfigurableTraceListenerWrapper(System.Diagnostics.TraceListener wrappedTraceListener, Microsoft.Practices.EnterpriseLibrary.Logging.ILoggingUpdateCoordinator coordinator) Resolving Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FormattedEventLogTraceListener,Event Log Listener?implementation (mapped from System.Diagnostics.TraceListener, Event Log Listener?implementation) Calling constructor Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FormattedEventLogTraceListener(System.String source, System.String log, System.String machineName, Microsoft.Practices.EnterpriseLibrary.Logging.Formatters.ILogFormatter formatter) "} System.Exception My web.config is as follows: <?xml version="1.0"?> <configuration> <configSections> <section name="loggingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.LoggingSettings, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true" /> <section name="exceptionHandling" type="Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Configuration.ExceptionHandlingSettings, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true" /> </configSections> <loggingConfiguration name="" tracingEnabled="true" defaultCategory="General"> <listeners> <add name="Event Log Listener" type="Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FormattedEventLogTraceListener, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" listenerDataType="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.FormattedEventLogTraceListenerData, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" source="Enterprise Library Logging" formatter="Text Formatter" log="C:\Blackbox.log" machineName="." traceOutputOptions="LogicalOperationStack, DateTime, Timestamp, Callstack" /> </listeners> <formatters> <add type="Microsoft.Practices.EnterpriseLibrary.Logging.Formatters.TextFormatter, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" template="Timestamp: {timestamp}{newline}&#xA;Message: {message}{newline}&#xA;Category: {category}{newline}&#xA;Priority: {priority}{newline}&#xA;EventId: {eventid}{newline}&#xA;Severity: {severity}{newline}&#xA;Title:{title}{newline}&#xA;Machine: {localMachine}{newline}&#xA;App Domain: {localAppDomain}{newline}&#xA;ProcessId: {localProcessId}{newline}&#xA;Process Name: {localProcessName}{newline}&#xA;Thread Name: {threadName}{newline}&#xA;Win32 ThreadId:{win32ThreadId}{newline}&#xA;Extended Properties: {dictionary({key} - {value}{newline})}" name="Text Formatter" /> </formatters> <categorySources> <add switchValue="All" name="General"> <listeners> <add name="Event Log Listener" /> </listeners> </add> </categorySources> <specialSources> <allEvents switchValue="All" name="All Events" /> <notProcessed switchValue="All" name="Unprocessed Category" /> <errors switchValue="All" name="Logging Errors &amp; Warnings"> <listeners> <add name="Event Log Listener" /> </listeners> </errors> </specialSources> </loggingConfiguration> <exceptionHandling> <exceptionPolicies> <add name="LogPolicy"> <exceptionTypes> <add name="All Exceptions" type="System.Exception, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" postHandlingAction="NotifyRethrow"> <exceptionHandlers> <add name="Logging Exception Handler" type="Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging.LoggingExceptionHandler, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" logCategory="General" eventId="100" severity="Error" title="Enterprise Library Exception Handling" formatterType="Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.TextExceptionFormatter, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling" priority="0" /> </exceptionHandlers> </add> </exceptionTypes> </add> <add name="WcfExceptionShielding"> <exceptionTypes> <add name="InvalidOperationException" type="System.InvalidOperationException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" postHandlingAction="ThrowNewException"> <exceptionHandlers> <add type="Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.WCF.FaultContractExceptionHandler, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.WCF, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" exceptionMessageResourceType="" exceptionMessageResourceName="This is the message" exceptionMessage="This is the exception" faultContractType="Blackbox.Service.WCFFault, Blackbox.Service, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" name="Fault Contract Exception Handler"> <mappings> <add source="{Guid}" name="Id" /> <add source="{Message}" name="MessageText" /> </mappings> </add> </exceptionHandlers> </add> </exceptionTypes> </add> </exceptionPolicies> </exceptionHandling> <connectionStrings> <add name="CompassEntities" connectionString="metadata=~\bin\CompassModel.csdl|~\bin\CompassModel.ssdl|~\bin\CompassModel.msl;provider=Devart.Data.Oracle;provider connection string=&quot;User Id=foo;Password=foo;Server=foo64mo;Home=OraClient11g_home1;Persist Security Info=True&quot;" providerName="System.Data.EntityClient" /> <add name="BlackboxEntities" connectionString="metadata=~\bin\BlackboxModel.csdl|~\bin\BlackboxModel.ssdl|~\bin\BlackboxModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=sqldev1\cps;Initial Catalog=FundServ;Integrated Security=True;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" /> </connectionStrings> <system.web> <compilation debug="true" strict="false" explicit="true" targetFramework="4.0" /> </system.web> <system.serviceModel> <behaviors> <serviceBehaviors> <behavior> <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment --> <serviceMetadata httpGetEnabled="true"/> <!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information --> <serviceDebug includeExceptionDetailInFaults="false"/> </behavior> </serviceBehaviors> </behaviors> <serviceHostingEnvironment multipleSiteBindingsEnabled="true" /> </system.serviceModel> <system.webServer> <modules runAllManagedModulesForAllRequests="true"/> </system.webServer> </configuration> My code is as follows: Public Shared Function LogException(ByVal pException As System.Exception) As Boolean Return ExceptionPolicy.HandleException(pException, "LogPolicy") End Function Any assistance is appreciated.

  Read the article

• how to create multiple pages in Xcode iphone apps

  - by al7r

  Hi there, i am starting my experience with iphone sdk. and i have a question, which is i am trying to create two pages to the app but i don't know how to link them or design them. like when i start the Xcode i find one page named View to design in it, i want to make that page a welcoming page then the user choose one of the three choices he see in that page. Once he clicked on one of them the program take him to the next page or the page he chose. thank you

  Read the article

• MVC repository pattern design decision

  - by bradjive

  I have an asp .net MVC application and recently started implementing the repository pattern with a service validation layer, much like this. I've been creating one repository/service for each model that I create. Is this overkill? Instead, should I create one repository/service for each logical business area that provides CRUD for many different models? To me, it seems like I'm either cluttering the project tree with many files or cluttering a class with many methods. 6 one way half dozen the other. Can you think of any good arguments either way?

  Read the article

• What are the maven-2 best practices

  - by c0mrade

  Hello everyone, Maven is very impressive tool, I've used it for few weeks now and almost every day I learn something new about maven. What do you think are the best practices? I found this relevant on the google http://www.sonatype.com/people/2009/01/maven-continuous-integration-best-practices/ , others are not relevant at all, and maven apache documentation is not good organized so its hard to pick up on things if you don't know what you are looking for. Any suggestions ?

  Read the article

• XML Parsing from Non-XML Document

  - by Neel Basu

  in a xml/non-xml File there may exist some XML Block that I need to parse and replace with some other string.. The Scenario is something like this.. Some Text <cnt:use name="abc" call="xyz"> <cnt:param name="x" value="2" /> </cnt:use> Some Text There is no guarantee that the document is a proper XML document. (there may exist some unclosed Tags. or some other common mistakes that a Stupid people can make while typing HTML). so I can't use SAX or DOM. I can't even pass it to XSLT (am I right ?). So Whats the best way to extract the <cnt:*> part from the non-xml Document. and read it then replace with something else.

  Read the article

• Singleton pattern in web applications

  - by ryudice

  I'm using a singleton pattern for the datacontext in my web application so that I dont have to instantiate it every time, however I'm not sure how web applications work, does IIS open a thread for every user connected? if so, what would happend if my singleton is not thread safe? Also, is it OK to use a singleton pattern for the datacontext? Thanks.

  Read the article

• "Presenter First" vs "Passive View" MVP?

  - by Bermo

  Is the "Presenter First" MVP pattern the same as the "Passive View"? If not, how do they differ?

  Read the article

• [Principles] Concrete Type or Interface for method return type?

  - by SDReyes

  In general terms, whats the better election for a method's return type: a concrete type or an interface? In most cases, I tend to use concrete types as the return type for methods. because I believe that an concrete type is more flexible for further use and exposes more functionality. The dark side of this: Coupling. The angelic one: A concrete type contains per-se the interface you would going to return initially, and extra functionality. What's your thumb's rule? Is there any programming principle for this? BONUS: This is an example of what I mean http://stackoverflow.com/questions/491375/readonlycollection-or-ienumerable-for-exposing-member-collections

  Read the article

• C# Design How to Elegantly wrap a DAL class

  - by guazz

  I have an application which uses MyGeneration's dOODads ORM to generate it's Data Access Layer. dOODad works by generating a persistance class for each table in the database. It works like so: // Load and Save Employees emps = new Employees(); if(emps.LoadByPrimaryKey(42)) { emps.LastName = "Just Got Married"; emps.Save(); } // Add a new record Employees emps = new Employees(); emps.AddNew(); emps.FirstName = "Mr."; emps.LastName = "dOOdad"; emps.Save(); // After save the identity column is already here for me. int i = emps.EmployeeID; // Dynamic Query - All Employees with 'A' in thier last name Employees emps = new Employees(); emps.Where.LastName.Value = "%A%"; emps.Where.LastName.Operator = WhereParameter.Operand.Like; emps.Query.Load(); For the above example(i.e. Employees DAL object) I would like to know what is the best method/technique to abstract some of the implementation details on my classes. I don't believe that an Employee class should have Employees(the DAL) specifics in its methods - or perhaps this is acceptable? Is it possible to implement some form of repository pattern? Bear in mind that this is a high volume, perfomacne critical application. Thanks, j

  Read the article

• How to handle payment types with varying properties in the most elegant way.

  - by Byron Sommardahl

  I'm using ASP.NET MVC 2. Keeping it simple, I have three payment types: credit card, e-check, or "bill me later". I want to: choose one payment type display some fields for one payment type in my view run some logic using those fields (specific to the type) display a confirmation view run some more logic using those fields (specific to the type) display a receipt view Each payment type has fields specific to the type... maybe 2 fields, maybe more. For now, I know how many and what fields, but more could be added. I believe the best thing for my views is to have a partial view per payment type to handle the different fields and let the controller decide which partial to render (if you have a better option, I'm open). My real problem comes from the logic that happens in the controller between views. Each payment type has a variable number of fields. I'd like to keep everything strongly typed, but it feels like some sort of dictionary is the only option. Add to that specific logic that runs depending on the payment type. In an effort to keep things strongly typed, I've created a class for each payment type. No interface or inherited type since the fields are different per payment type. Then, I've got a Submit() method for each payment type. Then, while the controller is deciding which partial view to display, it also assigns the target of the submit action. This is not elegant solution and feels very wrong. I'm reaching out for a hand. How would you do this?

  Read the article

• MVVM Madness: Commands

  - by JP

  I like MVVM. I don't love it, but like it. Most of it makes sense. But, I keep reading articles that encourage you to write a lot of code so that you can write XAML and don't have to write any code in the code-behind. Let me give you an example. Recently I wanted to hookup a command in my ViewModel to a ListView MouseDoubleClickEvent. I wasn't quite sure how to do this. Fortunately, Google has answers for everything. I found the following articles: http://blog.functionalfun.net/2008/09/hooking-up-commands-to-events-in-wpf.html http://joyfulwpf.blogspot.com/2009/05/mvvm-invoking-command-on-attached-event.html http://sachabarber.net/?p=514 http://geekswithblogs.net/HouseOfBilz/archive/2009/08/27/adventures-in-mvvm-ndash-binding-commands-to-any-event.aspx http://marlongrech.wordpress.com/2008/12/13/attachedcommandbehavior-v2-aka-acb/ While the solutions were helpful in my understanding of commands, there were problems. Some of the aforementioned solutions rendered the WPF designer unusable because of a common hack of appending "Internal" after a dependency property; the WPF designer can't find it, but the CLR can. Some of the solutions didn't allow multiple commands to the same control. Some of the solutions didn't allow parameters. After experimenting for a few hours I just decided to do this: private void ListView_MouseDoubleClick(object sender, MouseButtonEventArgs e) { ListView lv = sender as ListView; MyViewModel vm = this.DataContext as MyViewModel; vm.DoSomethingCommand.Execute(lv.SelectedItem); } So, MVVM purists, please tell me what's wrong with this? I can still Unit test my command. This seems very practical, but seems to violate the guideline of "ZOMG... you have code in your code-behind!!!!" Please share your thoughts. Thanks in advance.

  Read the article

• Conditional Markup in aspx

  - by Dynde

  Hi... I have a ListView. If I want to base the html markup on a condition in respects to the databound item, what would be the best way to do that? What I mean is, is there any other way then putting <% % if/else blocks directly in the markup? I'm aware that a really ugly way of doing it, is putting html markup in the database field, and just let the Eval() squeeze out the proper markup (I'm not doing that). I would like to avoid putting actual <% % C# blocks in the code as well. Any good ideas?

  Read the article

• Question About Example In Robert C Martin's _Clean Code_

  - by Jonah

  This is a question about the concept of a function doing only one thing. It won't make sense without some relevant passages for context, so I'll quote them here. They appear on pgs 37-38: To say this differently, we want to be able to read the program as though it were a set of TO paragraphs, each of which is describing the current level of abstraction and referencing subsequent TO paragraphs at the next level down. To include the setups and teardowns, we include setups, then we include the test page content, and then we include the teardowns. To include the setups, we include the suite setup if this is a suite, then we include the regular setup. It turns out to be very dif?cult for programmers to learn to follow this rule and write functions that stay at a single level of abstraction. But learning this trick is also very important. It is the key to keeping functions short and making sure they do “one thing.” Making the code read like a top-down set of TO paragraphs is an effective technique for keeping the abstraction level consistent. He then gives the following example of poor code: public Money calculatePay(Employee e) throws InvalidEmployeeType { switch (e.type) { case COMMISSIONED: return calculateCommissionedPay(e); case HOURLY: return calculateHourlyPay(e); case SALARIED: return calculateSalariedPay(e); default: throw new InvalidEmployeeType(e.type); } } and explains the problems with it as follows: There are several problems with this function. First, it’s large, and when new employee types are added, it will grow. Second, it very clearly does more than one thing. Third, it violates the Single Responsibility Principle7 (SRP) because there is more than one reason for it to change. Fourth, it violates the Open Closed Principle8 (OCP) because it must change whenever new types are added. Now my questions. To begin, it's clear to me how it violates the OCP, and it's clear to me that this alone makes it poor design. However, I am trying to understand each principle, and it's not clear to me how SRP applies. Specifically, the only reason I can imagine for this method to change is the addition of new employee types. There is only one "axis of change." If details of the calculation needed to change, this would only affect the submethods like "calculateHourlyPay()" Also, while in one sense it is obviously doing 3 things, those three things are all at the same level of abstraction, and can all be put into a TO paragraph no different from the example one: TO calculate pay for an employee, we calculate commissioned pay if the employee is commissioned, hourly pay if he is hourly, etc. So aside from its violation of the OCP, this code seems to conform to Martin's other requirements of clean code, even though he's arguing it does not. Can someone please explain what I am missing? Thanks.

  Read the article

• robocode engine: how to design (write) the runtime engine -- the robot world

  - by Bob

  IBM has (had) a free learn-Java program called RoboCode, in which custom robots could be written that would then do battle in a 2D space. I would like to write the environment that supports such robots, but don't know what pattern or design to use. Each robot is a thread. Each thread is given a certain (indeterminate) amount of run-time by the JRE. A robot world engine would start by building a list of the players/robots, then enter a loop that allows each player in turn to do whatever it likes: move forward, turn left, fire toward the northwest corner, whatever. Each robot is also informed of events of interest: an enemy or several enemies are within range, it has been hit by a bullet, etc. The combination of handling threads that are also event listeners (are they also producers?) confuses me; it seems that there's more to the game engine. Even some general ideas would help. TIA.

  Read the article

• MVP on Asp.Net WebForms

  - by Nicolas Irisarri

  I'm not clear about this.... When having a gridview on the View, is the controller who has to set up the Data source, columns, etc? or I just have to expose the DataBinding stuff, fire it from the controller and let the html/codebehind on the view handle all the rendering and wiring up? To be more precise: on the view should I have private GridView _gv public _IList<Poco> Source { get {_gv.DataSource;} set {_gv.DataSource = value; _gv.DataBind();} } Or should it be (from http://stackoverflow.com/questions/153222/mvp-pattern-passive-view-and-exposing-complex-types-through-iview-asp-net-web) private GridView _datasource; public DataSource { get { return _datasource; } set { _datasource = value; _datasource.DataBind(); } } Maybe I'm having it all wrong .... Where can I find an example that is not a "Hello world" example on MVP for ASP.Net???

  Read the article

• Noftification between J2EE components.

  - by Pratik

  Hi There! I have a design problem . My application has multiple J2EE components ,In simple terms one acts as a service provider(Non UI) and others are consumers(UI webapp) . The consumer gets the configuration data from the service provider(this basically reads the data from DB) during the start up and stores it in the Cache. The cache gets refreshed after periodic time to reflect any changes done at the database. The Problem Apart from the cache refresh ,I also want to notify the consumers when someone changes the DB . that configuration has been changed please reload it. What notification mechanism's can I use to achieve this. Thanks! Pratik

  Read the article

• singleton vs factory?

  - by fayer

  i've got 3 Log classes that all implements iLog interface: DatabaseLog FileLog ScreenLog there can only be one instance of them. initially i though of using single pattern for each class but then i thought why not use a factory for instantiation instead, cause then i wont have to create single pattern for each one of them and for all future Log classes. and maybe someone would want them as multiple objects in the future. so my questions is: should i use factory or singleton pattern here?

  Read the article

• Repository pattern with lazying loading using POCO

  - by Simon G

  Hi, I'm in the process of starting a new project and creating the business objects and data access etc. I'm just using plain old clr objects rather than any orms. I've created two class libraries: 1) Business Objects - holds all my business objects, all this objects are light weight with only properties and business rules. 2) Repository - this is for all my data access. The majority of my objects will have child list in and my question is what is the best way to lazy load these values as I don't want to bring back unnecessary information if I dont need to. I've thought about when using the "get" on the child property to check if its "null" and if it is call my repository to get the child information. This has two problems from what I can see: 1) The object "knows" how to get itself I would rather no data access logic be held in the object. 2) This required both classes to reference each other which in visual studio throws a circular dependency error. Does anyone have any suggestions on how to overcome this issue or any recommendations on my projects layout and where it can be improved? Thanks

  Read the article

• Notification between J2EE components.

  - by Pratik

  Hi There! I have a design problem . My application has multiple J2EE components ,In simple terms one acts as a service provider(Non UI) and others are consumers(UI webapp) . The consumer gets the configuration data from the service provider(this basically reads the data from DB) during the start up and stores it in the Cache. The cache gets refreshed after periodic time to reflect any changes done at the database. The Problem Apart from the cache refresh ,I also want to notify the consumers when someone changes the DB . that configuration has been changed please reload it. What notification mechanism's can I use to achieve this. Thanks! Pratik

  Read the article

• Why is IoC / DI not common in Python?

  - by tux21b

  In Java IoC / DI is a very common practice which is extensively used in web applications, nearly all available frameworks and Java EE. On the other hand, there are also lots of big Python web applications, but beside of Zope (which I've heard should be really horrible to code) IoC doesn't seem to be very common in the Python world. (Please name some examples if you think that I'm wrong). There are of course several clones of popular Java IoC frameworks available for Python, springpython for example. But none of them seems to get used practically. At least, I've never stumpled upon a Django or sqlalchemy+<insert your favorite wsgi toolkit here> based web application which uses something like that. In my opinion IoC has reasonable advantages and would make it easy to replace the django-default-user-model for example, but extensive usage of interface classes and IoC in Python looks a bit odd and not »pythonic«. But maybe someone has a better explanation, why IoC isn't widely used in Python.

  Read the article

• What are the downsides to using Dependency Injection?

  - by Epaga

  I'm trying to introduce DI as a pattern here at work and one of our lead developers would like to know: What - if any - are the downsides to using the Dependency Injection pattern? Note I'm looking here for an - if possible - exhaustive list, not a subjective discussion on the topic.

  Read the article

< Previous Page | 39 40 41 42 43 44 45 46 47 48 49 50  | Next Page >