poorly paid coder - Page 85

Dynamically loading Assemblies to reduce Runtime Depencies

- by Rick Strahl

I've been working on a request to the West Wind Application Configuration library to add JSON support. The config library is a very easy to use code-first approach to configuration: You create a class that holds the configuration data that inherits from a base configuration class, and then assign a persistence provider at runtime that determines where and how the configuration data is store. Currently the library supports .NET Configuration stores (web.config/app.config), XML files, SQL records and string storage.About once a week somebody asks me about JSON support and I've deflected this question for the longest time because frankly I think that JSON as a configuration store doesn't really buy a heck of a lot over XML. Both formats require the user to perform some fixup of the plain configuration data - in XML into XML tags, with JSON using JSON delimiters for properties and property formatting rules. Sure JSON is a little less verbose and maybe a little easier to read if you have hierarchical data, but overall the differences are pretty minor in my opinion. And yet - the requests keep rolling in.Hard Link Issues in a Component LibraryAnother reason I've been hesitant is that I really didn't want to pull in a dependency on an external JSON library - in this case JSON.NET - into the core library. If you're not using JSON.NET elsewhere I don't want a user to have to require a hard dependency on JSON.NET unless they want to use the JSON feature. JSON.NET is also sensitive to versions and doesn't play nice with multiple versions when hard linked. For example, when you have a reference to V4.4 in your project but the host application has a reference to version 4.5 you can run into assembly load problems. NuGet's Update-Package can solve some of this *if* you can recompile, but that's not ideal for a component that's supposed to be just plug and play. This is no criticism of JSON.NET - this really applies to any dependency that might change. So hard linking the DLL can be problematic for a number reasons, but the primary reason is to not force loading of JSON.NET unless you actually need it when you use the JSON configuration features of the library.Enter Dynamic LoadingSo rather than adding an assembly reference to the project, I decided that it would be better to dynamically load the DLL at runtime and then use dynamic typing to access various classes. This allows me to run without a hard assembly reference and allows more flexibility with version number differences now and in the future.But there are also a couple of downsides:No assembly reference means only dynamic access - no compiler type checking or IntellisenseRequirement for the host application to have reference to JSON.NET or else get runtime errorsThe former is minor, but the latter can be problematic. Runtime errors are always painful, but in this case I'm willing to live with this. If you want to use JSON configuration settings JSON.NET needs to be loaded in the project. If this is a Web project, it'll likely be there already.So there are a few things that are needed to make this work:Dynamically create an instance and optionally attempt to load an Assembly (if not loaded)Load types into dynamic variablesUse Reflection for a few tasks like statics/enumsThe dynamic keyword in C# makes the formerly most difficult Reflection part - method calls and property assignments - fairly painless. But as cool as dynamic is it doesn't handle all aspects of Reflection. Specifically it doesn't deal with object activation, truly dynamic (string based) member activation or accessing of non instance members, so there's still a little bit of work left to do with Reflection.Dynamic Object InstantiationThe first step in getting the process rolling is to instantiate the type you need to work with. This might be a two step process - loading the instance from a string value, since we don't have a hard type reference and potentially having to load the assembly. Although the host project might have a reference to JSON.NET, that instance might have not been loaded yet since it hasn't been accessed yet. In ASP.NET this won't be a problem, since ASP.NET preloads all referenced assemblies on AppDomain startup, but in other executable project, assemblies are just in time loaded only when they are accessed.Instantiating a type is a two step process: Finding the type reference and then activating it. Here's the generic code out of my ReflectionUtils library I use for this:/// <summary> /// Creates an instance of a type based on a string. Assumes that the type's /// </summary> /// <param name="typeName">Common name of the type</param> /// <param name="args">Any constructor parameters</param> /// <returns></returns> public static object CreateInstanceFromString(string typeName, params object[] args) { object instance = null; Type type = null; try { type = GetTypeFromName(typeName); if (type == null) return null; instance = Activator.CreateInstance(type, args); } catch { return null; } return instance; } /// <summary> /// Helper routine that looks up a type name and tries to retrieve the /// full type reference in the actively executing assemblies. /// </summary> /// <param name="typeName"></param> /// <returns></returns> public static Type GetTypeFromName(string typeName) { Type type = null; // Let default name binding find it type = Type.GetType(typeName, false); if (type != null) return type; // look through assembly list var assemblies = AppDomain.CurrentDomain.GetAssemblies(); // try to find manually foreach (Assembly asm in assemblies) { type = asm.GetType(typeName, false); if (type != null) break; } return type; } To use this for loading JSON.NET I have a small factory function that instantiates JSON.NET and sets a bunch of configuration settings on the generated object. The startup code also looks for failure and tries loading up the assembly when it fails since that's the main reason the load would fail. Finally it also caches the loaded instance for reuse (according to James the JSON.NET instance is thread safe and quite a bit faster when cached). Here's what the factory function looks like in JsonSerializationUtils:/// <summary> /// Dynamically creates an instance of JSON.NET /// </summary> /// <param name="throwExceptions">If true throws exceptions otherwise returns null</param> /// <returns>Dynamic JsonSerializer instance</returns> public static dynamic CreateJsonNet(bool throwExceptions = true) { if (JsonNet != null) return JsonNet; lock (SyncLock) { if (JsonNet != null) return JsonNet; // Try to create instance dynamic json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); if (json == null) { try { var ass = AppDomain.CurrentDomain.Load("Newtonsoft.Json"); json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); } catch (Exception ex) { if (throwExceptions) throw; return null; } } if (json == null) return null; json.ReferenceLoopHandling = (dynamic) ReflectionUtils.GetStaticProperty("Newtonsoft.Json.ReferenceLoopHandling", "Ignore"); // Enums as strings in JSON dynamic enumConverter = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.Converters.StringEnumConverter"); json.Converters.Add(enumConverter); JsonNet = json; } return JsonNet; }This code's purpose is to return a fully configured JsonSerializer instance. As you can see the code tries to create an instance and when it fails tries to load the assembly, and then re-tries loading.Once the instance is loaded some configuration occurs on it. Specifically I set the ReferenceLoopHandling option to not blow up immediately when circular references are encountered. There are a host of other small config setting that might be useful to set, but the default seem to be good enough in recent versions. Note that I'm setting ReferenceLoopHandling which requires an Enum value to be set. There's no real easy way (short of using the cardinal numeric value) to set a property or pass parameters from static values or enums. This means I still need to use Reflection to make this work. I'm using the same ReflectionUtils class I previously used to handle this for me. The function looks up the type and then uses Type.InvokeMember() to read the static property.Another feature I need is have Enum values serialized as strings rather than numeric values which is the default. To do this I can use the StringEnumConverter to convert enums to strings by adding it to the Converters collection.As you can see there's still a bit of Reflection to be done even in C# 4+ with dynamic, but with a few helpers this process is relatively painless.Doing the actual JSON ConversionFinally I need to actually do my JSON conversions. For the Utility class I need serialization that works for both strings and files so I created four methods that handle these tasks two each for serialization and deserialization for string and file.Here's what the File Serialization looks like:/// <summary> /// Serializes an object instance to a JSON file. /// </summary> /// <param name="value">the value to serialize</param> /// <param name="fileName">Full path to the file to write out with JSON.</param> /// <param name="throwExceptions">Determines whether exceptions are thrown or false is returned</param> /// <param name="formatJsonOutput">if true pretty-formats the JSON with line breaks</param> /// <returns>true or false</returns> public static bool SerializeToFile(object value, string fileName, bool throwExceptions = false, bool formatJsonOutput = false) { dynamic writer = null; FileStream fs = null; try { Type type = value.GetType(); var json = CreateJsonNet(throwExceptions); if (json == null) return false; fs = new FileStream(fileName, FileMode.Create); var sw = new StreamWriter(fs, Encoding.UTF8); writer = Activator.CreateInstance(JsonTextWriterType, sw); if (formatJsonOutput) writer.Formatting = (dynamic)Enum.Parse(FormattingType, "Indented"); writer.QuoteChar = '"'; json.Serialize(writer, value); } catch (Exception ex) { Debug.WriteLine("JsonSerializer Serialize error: " + ex.Message); if (throwExceptions) throw; return false; } finally { if (writer != null) writer.Close(); if (fs != null) fs.Close(); } return true; }You can see more of the dynamic invocation in this code. First I grab the dynamic JsonSerializer instance using the CreateJsonNet() method shown earlier which returns a dynamic. I then create a JsonTextWriter and configure a couple of enum settings on it, and then call Serialize() on the serializer instance with the JsonTextWriter that writes the output to disk. Although this code is dynamic it's still fairly short and readable.For full circle operation here's the DeserializeFromFile() version:/// <summary> /// Deserializes an object from file and returns a reference. /// </summary> /// <param name="fileName">name of the file to serialize to</param> /// <param name="objectType">The Type of the object. Use typeof(yourobject class)</param> /// <param name="binarySerialization">determines whether we use Xml or Binary serialization</param> /// <param name="throwExceptions">determines whether failure will throw rather than return null on failure</param> /// <returns>Instance of the deserialized object or null. Must be cast to your object type</returns> public static object DeserializeFromFile(string fileName, Type objectType, bool throwExceptions = false) { dynamic json = CreateJsonNet(throwExceptions); if (json == null) return null; object result = null; dynamic reader = null; FileStream fs = null; try { fs = new FileStream(fileName, FileMode.Open, FileAccess.Read); var sr = new StreamReader(fs, Encoding.UTF8); reader = Activator.CreateInstance(JsonTextReaderType, sr); result = json.Deserialize(reader, objectType); reader.Close(); } catch (Exception ex) { Debug.WriteLine("JsonNetSerialization Deserialization Error: " + ex.Message); if (throwExceptions) throw; return null; } finally { if (reader != null) reader.Close(); if (fs != null) fs.Close(); } return result; }This code is a little more compact since there are no prettifying options to set. Here JsonTextReader is created dynamically and it receives the output from the Deserialize() operation on the serializer.You can take a look at the full JsonSerializationUtils.cs file on GitHub to see the rest of the operations, but the string operations are very similar - the code is fairly repetitive.These generic serialization utilities isolate the dynamic serialization logic that has to deal with the dynamic nature of JSON.NET, and any code that uses these functions is none the wiser that JSON.NET is dynamically loaded.Using the JsonSerializationUtils WrapperThe final consumer of the SerializationUtils wrapper is an actual ConfigurationProvider, that is responsible for handling reading and writing JSON values to and from files. The provider is simple a small wrapper around the SerializationUtils component and there's very little code to make this work now:The whole provider looks like this:/// <summary> /// Reads and Writes configuration settings in .NET config files and /// sections. Allows reading and writing to default or external files /// and specification of the configuration section that settings are /// applied to. /// </summary> public class JsonFileConfigurationProvider<TAppConfiguration> : ConfigurationProviderBase<TAppConfiguration> where TAppConfiguration: AppConfiguration, new() { /// <summary> /// Optional - the Configuration file where configuration settings are /// stored in. If not specified uses the default Configuration Manager /// and its default store. /// </summary> public string JsonConfigurationFile { get { return _JsonConfigurationFile; } set { _JsonConfigurationFile = value; } } private string _JsonConfigurationFile = string.Empty; public override bool Read(AppConfiguration config) { var newConfig = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfiguration)) as TAppConfiguration; if (newConfig == null) { if(Write(config)) return true; return false; } DecryptFields(newConfig); DataUtils.CopyObjectData(newConfig, config, "Provider,ErrorMessage"); return true; } /// <summary> /// Return /// </summary> /// <typeparam name="TAppConfig"></typeparam> /// <returns></returns> public override TAppConfig Read<TAppConfig>() { var result = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfig)) as TAppConfig; if (result != null) DecryptFields(result); return result; } /// <summary> /// Write configuration to XmlConfigurationFile location /// </summary> /// <param name="config"></param> /// <returns></returns> public override bool Write(AppConfiguration config) { EncryptFields(config); bool result = JsonSerializationUtils.SerializeToFile(config, JsonConfigurationFile,false,true); // Have to decrypt again to make sure the properties are readable afterwards DecryptFields(config); return result; } }This incidentally demonstrates how easy it is to create a new provider for the West Wind Application Configuration component. Simply implementing 3 methods will do in most cases.Note this code doesn't have any dynamic dependencies - all that's abstracted away in the JsonSerializationUtils(). From here on, serializing JSON is just a matter of calling the static methods on the SerializationUtils class.Already, there are several other places in some other tools where I use JSON serialization this is coming in very handy. With a couple of lines of code I was able to add JSON.NET support to an older AJAX library that I use replacing quite a bit of code that was previously in use. And for any other manual JSON operations (in a couple of apps I use JSON Serialization for 'blob' like document storage) this is also going to be handy.Performance?Some of you might be thinking that using dynamic and Reflection can't be good for performance. And you'd be right… In performing some informal testing it looks like the performance of the native code is nearly twice as fast as the dynamic code. Most of the slowness is attributable to type lookups. To test I created a native class that uses an actual reference to JSON.NET and performance was consistently around 85-90% faster with the referenced code. That being said though - I serialized 10,000 objects in 80ms vs. 45ms so this isn't hardly slouchy. For the configuration component speed is not that important because both read and write operations typically happen once on first access and then every once in a while. But for other operations - say a serializer trying to handle AJAX requests on a Web Server one would be well served to create a hard dependency.Dynamic Loading - Worth it?On occasion dynamic loading makes sense. But there's a price to be paid in added code complexity and a performance hit. But for some operations that are not pivotal to a component or application and only used under certain circumstances dynamic loading can be beneficial to avoid having to ship extra files and loading down distributions. These days when you create new projects in Visual Studio with 30 assemblies before you even add your own code, trying to keep file counts under control seems a good idea. It's not the kind of thing you do on a regular basis, but when needed it can be a useful tool. Hopefully some of you find this information useful…© Rick Strahl, West Wind Technologies, 2005-2013Posted in .NET C# Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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Building a better mouse-trap – Improving the creation of XML Message Requests using Reflection, XML & XSLT

- by paulschapman

Introduction The way I previously created messages to send to the GovTalk service I used the XMLDocument to create the request. While this worked it left a number of problems; not least that for every message a special function would need to created. This is OK for the short term but the biggest cost in any software project is maintenance and this would be a headache to maintain. So the following is a somewhat better way of achieving the same thing. For the purposes of this article I am going to be using the CompanyNumberSearch request of the GovTalk service – although this technique would work for any service that accepted XML. The C# functions which send and receive the messages remain the same. The magic sauce in this is the XSLT which defines the structure of the request, and the use of objects in conjunction with reflection to provide the content. It is a bit like Sweet Chilli Sauce added to Chicken on a bed of rice. So on to the Sweet Chilli Sauce The Sweet Chilli Sauce The request to search for a company based on it’s number is as follows; <GovTalkMessage xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" > <EnvelopeVersion>1.0</EnvelopeVersion> <Header> <MessageDetails> <Class>NumberSearch</Class> <Qualifier>request</Qualifier> <TransactionID>1</TransactionID> </MessageDetails> <SenderDetails> <IDAuthentication> <SenderID>????????????????????????????????</SenderID> <Authentication> <Method>CHMD5</Method> <Value>????????????????????????????????</Value> </Authentication> </IDAuthentication> </SenderDetails> </Header> <GovTalkDetails> <Keys/> </GovTalkDetails> <Body> <NumberSearchRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://xmlgw.companieshouse.gov.uk/v1-0/schema/NumberSearch.xsd"> <PartialCompanyNumber>99999999</PartialCompanyNumber> <DataSet>LIVE</DataSet> <SearchRows>1</SearchRows> </NumberSearchRequest> </Body> </GovTalkMessage> This is the XML that we send to the GovTalk Service and we get back a list of companies that match the criteria passed A message is structured in two parts; The envelope which identifies the person sending the request, with the name of the request, and the body which gives the detail of the company we are looking for. The Chilli What makes it possible is the use of XSLT to define the message – and serialization to convert each request object into XML. To start we need to create an object which will represent the contents of the message we are sending. However there is a common properties in all the messages that we send to Companies House. These properties are as follows SenderId – the id of the person sending the message SenderPassword – the password associated with Id TransactionId – Unique identifier for the message AuthenticationValue – authenticates the request Because these properties are unique to the Companies House message, and because they are shared with all messages they are perfect candidates for a base class. The class is as follows; using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Security.Cryptography; using System.Text; using System.Text.RegularExpressions; using Microsoft.WindowsAzure.ServiceRuntime; namespace CompanyHub.Services { public class GovTalkRequest { public GovTalkRequest() { try { SenderID = RoleEnvironment.GetConfigurationSettingValue("SenderId"); SenderPassword = RoleEnvironment.GetConfigurationSettingValue("SenderPassword"); TransactionId = DateTime.Now.Ticks.ToString(); AuthenticationValue = EncodePassword(String.Format("{0}{1}{2}", SenderID, SenderPassword, TransactionId)); } catch (System.Exception ex) { throw ex; } } /// <summary> /// returns the Sender ID to be used when communicating with the GovTalk Service /// </summary> public String SenderID { get; set; } /// <summary> /// return the password to be used when communicating with the GovTalk Service /// </summary> public String SenderPassword { get; set; } // end SenderPassword /// <summary> /// Transaction Id - uses the Time and Date converted to Ticks /// </summary> public String TransactionId { get; set; } // end TransactionId /// <summary> /// calculate the authentication value that will be used when /// communicating with /// </summary> public String AuthenticationValue { get; set; } // end AuthenticationValue property /// <summary> /// encodes password(s) using MD5 /// </summary> /// <param name="clearPassword"></param> /// <returns></returns> public static String EncodePassword(String clearPassword) { MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider(); byte[] hashedBytes; UTF32Encoding encoder = new UTF32Encoding(); hashedBytes = md5Hasher.ComputeHash(ASCIIEncoding.Default.GetBytes(clearPassword)); String result = Regex.Replace(BitConverter.ToString(hashedBytes), "-", "").ToLower(); return result; } } } There is nothing particularly clever here, except for the EncodePassword method which hashes the value made up of the SenderId, Password and Transaction id. Each message inherits from this object. So for the Company Number Search in addition to the properties above we need a partial number, which dataset to search – for the purposes of the project we only need to search the LIVE set so this can be set in the constructor and the SearchRows. Again all are set as properties. With the SearchRows and DataSet initialized in the constructor. public class CompanyNumberSearchRequest : GovTalkRequest, IDisposable { /// <summary> /// /// </summary> public CompanyNumberSearchRequest() : base() { DataSet = "LIVE"; SearchRows = 1; } /// <summary> /// Company Number to search against /// </summary> public String PartialCompanyNumber { get; set; } /// <summary> /// What DataSet should be searched for the company /// </summary> public String DataSet { get; set; } /// <summary> /// How many rows should be returned /// </summary> public int SearchRows { get; set; } public void Dispose() { DataSet = String.Empty; PartialCompanyNumber = String.Empty; DataSet = "LIVE"; SearchRows = 1; } } As well as inheriting from our base class, I have also inherited from IDisposable – not just because it is just plain good practice to dispose of objects when coding, but it gives also gives us more versatility when using the object. There are four stages in making a request and this is reflected in the four methods we execute in making a call to the Companies House service; Create a request Send a request Check the status If OK then get the results of the request I’ve implemented each of these stages within a static class called Toolbox – which also means I don’t need to create an instance of the class to use it. When making a request there are three stages; Get the template for the message Serialize the object representing the message Transform the serialized object using a predefined XSLT file. Each of my templates I have defined as an embedded resource. When retrieving a resource of this kind we have to include the full namespace to the resource. In making the code re-usable as much as possible I defined the full ‘path’ within the GetRequest method. requestFile = String.Format("CompanyHub.Services.Schemas.{0}", RequestFile); So we now have the full path of the file within the assembly. Now all we need do is retrieve the assembly and get the resource. asm = Assembly.GetExecutingAssembly(); sr = asm.GetManifestResourceStream(requestFile); Once retrieved So this can be returned to the calling function and we now have a stream of XSLT to define the message. Time now to serialize the request to create the other side of this message. // Serialize object containing Request, Load into XML Document t = Obj.GetType(); ms = new MemoryStream(); serializer = new XmlSerializer(t); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); serializer.Serialize(xmlTextWriter, Obj); ms = (MemoryStream)xmlTextWriter.BaseStream; GovTalkRequest = Toolbox.ConvertByteArrayToString(ms.ToArray()); First off we need the type of the object so we make a call to the GetType method of the object containing the Message properties. Next we need a MemoryStream, XmlSerializer and an XMLTextWriter so these can be initialized. The object is serialized by making the call to the Serialize method of the serializer object. The result of that is then converted into a MemoryStream. That MemoryStream is then converted into a string. ConvertByteArrayToString This is a fairly simple function which uses an ASCIIEncoding object found within the System.Text namespace to convert an array of bytes into a string. public static String ConvertByteArrayToString(byte[] bytes) { System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding(); return enc.GetString(bytes); } I only put it into a function because I will be using this in various places. The Sauce When adding support for other messages outside of creating a new object to store the properties of the message, the C# components do not need to change. It is in the XSLT file that the versatility of the technique lies. The XSLT file determines the format of the message. For the CompanyNumberSearch the XSLT file is as follows; <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:template match="/"> <GovTalkMessage xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" > <EnvelopeVersion>1.0</EnvelopeVersion> <Header> <MessageDetails> <Class>NumberSearch</Class> <Qualifier>request</Qualifier> <TransactionID> <xsl:value-of select="CompanyNumberSearchRequest/TransactionId"/> </TransactionID> </MessageDetails> <SenderDetails> <IDAuthentication> <SenderID><xsl:value-of select="CompanyNumberSearchRequest/SenderID"/></SenderID> <Authentication> <Method>CHMD5</Method> <Value> <xsl:value-of select="CompanyNumberSearchRequest/AuthenticationValue"/> </Value> </Authentication> </IDAuthentication> </SenderDetails> </Header> <GovTalkDetails> <Keys/> </GovTalkDetails> <Body> <NumberSearchRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://xmlgw.companieshouse.gov.uk/v1-0/schema/NumberSearch.xsd"> <PartialCompanyNumber> <xsl:value-of select="CompanyNumberSearchRequest/PartialCompanyNumber"/> </PartialCompanyNumber> <DataSet> <xsl:value-of select="CompanyNumberSearchRequest/DataSet"/> </DataSet> <SearchRows> <xsl:value-of select="CompanyNumberSearchRequest/SearchRows"/> </SearchRows> </NumberSearchRequest> </Body> </GovTalkMessage> </xsl:template> </xsl:stylesheet> The outer two tags define that this is a XSLT stylesheet and the root tag from which the nodes are searched for. The GovTalkMessage is the format of the message that will be sent to Companies House. We first set up the XslCompiledTransform object which will transform the XSLT template and the serialized object into the request to Companies House. xslt = new XslCompiledTransform(); resultStream = new MemoryStream(); writer = new XmlTextWriter(resultStream, Encoding.ASCII); doc = new XmlDocument(); The Serialize method require XmlTextWriter to write the XML (writer) and a stream to place the transferred object into (writer). The XML will be loaded into an XMLDocument object (doc) prior to the transformation. // create XSLT Template xslTemplate = Toolbox.GetRequest(Template); xslTemplate.Seek(0, SeekOrigin.Begin); templateReader = XmlReader.Create(xslTemplate); xslt.Load(templateReader); I have stored all the templates as a series of Embedded Resources and the GetRequestCall takes the name of the template and extracts the relevent XSLT file. /// <summary> /// Gets the framwork XML which makes the request /// </summary> /// <param name="RequestFile"></param> /// <returns></returns> public static Stream GetRequest(String RequestFile) { String requestFile = String.Empty; Stream sr = null; Assembly asm = null; try { requestFile = String.Format("CompanyHub.Services.Schemas.{0}", RequestFile); asm = Assembly.GetExecutingAssembly(); sr = asm.GetManifestResourceStream(requestFile); } catch (Exception) { throw; } finally { asm = null; } return sr; } // end private static stream GetRequest We first take the template name and expand it to include the full namespace to the Embedded Resource I like to keep all my schemas in the same directory and so the namespace reflects this. The rest is the default namespace for the project. Then we get the currently executing assembly (which will contain the resources with the call to GetExecutingAssembly() ) Finally we get a stream which contains the XSLT file. We use this stream and then load an XmlReader with the contents of the template, and that is in turn loaded into the XslCompiledTransform object. We convert the object containing the message properties into Xml by serializing it; calling the Serialize() method of the XmlSerializer object. To set up the object we do the following; t = Obj.GetType(); ms = new MemoryStream(); serializer = new XmlSerializer(t); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); We first determine the type of the object being transferred by calling GetType() We create an XmlSerializer object by passing the type of the object being serialized. The serializer writes to a memory stream and that is linked to an XmlTextWriter. Next job is to serialize the object and load it into an XmlDocument. serializer.Serialize(xmlTextWriter, Obj); ms = (MemoryStream)xmlTextWriter.BaseStream; xmlRequest = new XmlTextReader(ms); GovTalkRequest = Toolbox.ConvertByteArrayToString(ms.ToArray()); doc.LoadXml(GovTalkRequest); Time to transform the XML to construct the full request. xslt.Transform(doc, writer); resultStream.Seek(0, SeekOrigin.Begin); request = Toolbox.ConvertByteArrayToString(resultStream.ToArray()); So that creates the full request to be sent to Companies House. Sending the request So far we have a string with a request for the Companies House service. Now we need to send the request to the Companies House Service. Configuration within an Azure project There are entire blog entries written about configuration within an Azure project – most of this is out of scope for this article but the following is a summary. Configuration is defined in two files within the parent project *.csdef which contains the definition of configuration setting. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="OnlineCompanyHub" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition"> <WebRole name="CompanyHub.Host"> <InputEndpoints> <InputEndpoint name="HttpIn" protocol="http" port="80" /> </InputEndpoints> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> <Setting name="DataConnectionString" /> </ConfigurationSettings> </WebRole> <WebRole name="CompanyHub.Services"> <InputEndpoints> <InputEndpoint name="HttpIn" protocol="http" port="8080" /> </InputEndpoints> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> <Setting name="SenderId"/> <Setting name="SenderPassword" /> <Setting name="GovTalkUrl"/> </ConfigurationSettings> </WebRole> <WorkerRole name="CompanyHub.Worker"> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> </ConfigurationSettings> </WorkerRole> </ServiceDefinition> Above is the configuration definition from the project. What we are interested in however is the ConfigurationSettings tag of the CompanyHub.Services WebRole. There are four configuration settings here, but at the moment we are interested in the second to forth settings; SenderId, SenderPassword and GovTalkUrl The value of these settings are defined in the ServiceDefinition.cscfg file; <?xml version="1.0"?> <ServiceConfiguration serviceName="OnlineCompanyHub" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration"> <Role name="CompanyHub.Host"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="DataConnectionString" value="UseDevelopmentStorage=true" /> </ConfigurationSettings> </Role> <Role name="CompanyHub.Services"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="SenderId" value="UserID"/> <Setting name="SenderPassword" value="Password"/> <Setting name="GovTalkUrl" value="http://xmlgw.companieshouse.gov.uk/v1-0/xmlgw/Gateway"/> </ConfigurationSettings> </Role> <Role name="CompanyHub.Worker"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> </ConfigurationSettings> </Role> </ServiceConfiguration> Look for the Role tag that contains our project name (CompanyHub.Services). Having configured the parameters we can now transmit the request. This is done by ‘POST’ing a stream of XML to the Companies House servers. govTalkUrl = RoleEnvironment.GetConfigurationSettingValue("GovTalkUrl"); request = WebRequest.Create(govTalkUrl); request.Method = "POST"; request.ContentType = "text/xml"; writer = new StreamWriter(request.GetRequestStream()); writer.WriteLine(RequestMessage); writer.Close(); We use the WebRequest object to send the object. Set the method of sending to ‘POST’ and the type of data as text/xml. Once set up all we do is write the request to the writer – this sends the request to Companies House. Did the Request Work Part I – Getting the response Having sent a request – we now need the result of that request. response = request.GetResponse(); reader = response.GetResponseStream(); result = Toolbox.ConvertByteArrayToString(Toolbox.ReadFully(reader)); The WebRequest object has a GetResponse() method which allows us to get the response sent back. Like many of these calls the results come in the form of a stream which we convert into a string. Did the Request Work Part II – Translating the Response Much like XSLT and XML were used to create the original request, so it can be used to extract the response and by deserializing the result we create an object that contains the response. Did it work? It would be really great if everything worked all the time. Of course if it did then I don’t suppose people would pay me and others the big bucks so that our programmes do not a) Collapse in a heap (this is an area of memory) b) Blow every fuse in the place in a shower of sparks (this will probably not happen this being real life and not a Hollywood movie, but it was possible to blow the sound system of a BBC Model B with a poorly coded setting) c) Go nuts and trap everyone outside the airlock (this was from a movie, and unless NASA get a manned moon/mars mission set up unlikely to happen) d) Go nuts and take over the world (this was also from a movie, but please note life has a habit of being of exceeding the wildest imaginations of Hollywood writers (note writers – Hollywood executives have no imagination and judging by recent output of that town have turned plagiarism into an art form). e) Freeze in total confusion because the cleaner pulled the plug to the internet router (this has happened) So anyway – we need to check to see if our request actually worked. Within the GovTalk response there is a section that details the status of the message and a description of what went wrong (if anything did). I have defined an XSLT template which will extract these into an XML document. <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ev="http://www.govtalk.gov.uk/CM/envelope" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <xsl:template match="/"> <GovTalkStatus xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Status> <xsl:value-of select="ev:GovTalkMessage/ev:Header/ev:MessageDetails/ev:Qualifier"/> </Status> <Text> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Text"/> </Text> <Location> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Location"/> </Location> <Number> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Number"/> </Number> <Type> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Type"/> </Type> </GovTalkStatus> </xsl:template> </xsl:stylesheet> Only thing different about previous XSL files is the references to two namespaces ev & gt. These are defined in the GovTalk response at the top of the response; xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" If we do not put these references into the XSLT template then the XslCompiledTransform object will not be able to find the relevant tags. Deserialization is a fairly simple activity. encoder = new ASCIIEncoding(); ms = new MemoryStream(encoder.GetBytes(statusXML)); serializer = new XmlSerializer(typeof(GovTalkStatus)); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); messageStatus = (GovTalkStatus)serializer.Deserialize(ms); We set up a serialization object using the object type containing the error state and pass to it the results of a transformation between the XSLT above and the GovTalk response. Now we have an object containing any error state, and the error message. All we need to do is check the status. If there is an error then we can flag an error. If not then we extract the results and pass that as an object back to the calling function. We go this by guess what – defining an XSLT template for the result and using that to create an Xml Stream which can be deserialized into a .Net object. In this instance the XSLT to create the result of a Company Number Search is; <?xml version="1.0" encoding="us-ascii"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ev="http://www.govtalk.gov.uk/CM/envelope" xmlns:sch="http://xmlgw.companieshouse.gov.uk/v1-0/schema" exclude-result-prefixes="ev"> <xsl:template match="/"> <CompanySearchResult xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <CompanyNumber> <xsl:value-of select="ev:GovTalkMessage/ev:Body/sch:NumberSearch/sch:CoSearchItem/sch:CompanyNumber"/> </CompanyNumber> <CompanyName> <xsl:value-of select="ev:GovTalkMessage/ev:Body/sch:NumberSearch/sch:CoSearchItem/sch:CompanyName"/> </CompanyName> </CompanySearchResult> </xsl:template> </xsl:stylesheet> and the object definition is; using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace CompanyHub.Services { public class CompanySearchResult { public CompanySearchResult() { CompanyNumber = String.Empty; CompanyName = String.Empty; } public String CompanyNumber { get; set; } public String CompanyName { get; set; } } } Our entire code to make calls to send a request, and interpret the results are; String request = String.Empty; String response = String.Empty; GovTalkStatus status = null; fault = null; try { using (CompanyNumberSearchRequest requestObj = new CompanyNumberSearchRequest()) { requestObj.PartialCompanyNumber = CompanyNumber; request = Toolbox.CreateRequest(requestObj, "CompanyNumberSearch.xsl"); response = Toolbox.SendGovTalkRequest(request); status = Toolbox.GetMessageStatus(response); if (status.Status.ToLower() == "error") { fault = new HubFault() { Message = status.Text }; } else { Object obj = Toolbox.GetGovTalkResponse(response, "CompanyNumberSearchResult.xsl", typeof(CompanySearchResult)); } } } catch (FaultException<ArgumentException> ex) { fault = new HubFault() { FaultType = ex.Detail.GetType().FullName, Message = ex.Detail.Message }; } catch (System.Exception ex) { fault = new HubFault() { FaultType = ex.GetType().FullName, Message = ex.Message }; } finally { } Wrap up So there we have it – a reusable set of functions to send and interpret XML results from an internet based service. The code is reusable with a little change with any service which uses XML as a transport mechanism – and as for the Companies House GovTalk service all I need to do is create various objects for the result and message sent and the relevent XSLT files. I might need minor changes for other services but something like 70-90% will be exactly the same.

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Dynamically loading Assemblies to reduce Runtime Dependencies

- by Rick Strahl

I've been working on a request to the West Wind Application Configuration library to add JSON support. The config library is a very easy to use code-first approach to configuration: You create a class that holds the configuration data that inherits from a base configuration class, and then assign a persistence provider at runtime that determines where and how the configuration data is store. Currently the library supports .NET Configuration stores (web.config/app.config), XML files, SQL records and string storage.About once a week somebody asks me about JSON support and I've deflected this question for the longest time because frankly I think that JSON as a configuration store doesn't really buy a heck of a lot over XML. Both formats require the user to perform some fixup of the plain configuration data - in XML into XML tags, with JSON using JSON delimiters for properties and property formatting rules. Sure JSON is a little less verbose and maybe a little easier to read if you have hierarchical data, but overall the differences are pretty minor in my opinion. And yet - the requests keep rolling in.Hard Link Issues in a Component LibraryAnother reason I've been hesitant is that I really didn't want to pull in a dependency on an external JSON library - in this case JSON.NET - into the core library. If you're not using JSON.NET elsewhere I don't want a user to have to require a hard dependency on JSON.NET unless they want to use the JSON feature. JSON.NET is also sensitive to versions and doesn't play nice with multiple versions when hard linked. For example, when you have a reference to V4.4 in your project but the host application has a reference to version 4.5 you can run into assembly load problems. NuGet's Update-Package can solve some of this *if* you can recompile, but that's not ideal for a component that's supposed to be just plug and play. This is no criticism of JSON.NET - this really applies to any dependency that might change. So hard linking the DLL can be problematic for a number reasons, but the primary reason is to not force loading of JSON.NET unless you actually need it when you use the JSON configuration features of the library.Enter Dynamic LoadingSo rather than adding an assembly reference to the project, I decided that it would be better to dynamically load the DLL at runtime and then use dynamic typing to access various classes. This allows me to run without a hard assembly reference and allows more flexibility with version number differences now and in the future.But there are also a couple of downsides:No assembly reference means only dynamic access - no compiler type checking or IntellisenseRequirement for the host application to have reference to JSON.NET or else get runtime errorsThe former is minor, but the latter can be problematic. Runtime errors are always painful, but in this case I'm willing to live with this. If you want to use JSON configuration settings JSON.NET needs to be loaded in the project. If this is a Web project, it'll likely be there already.So there are a few things that are needed to make this work:Dynamically create an instance and optionally attempt to load an Assembly (if not loaded)Load types into dynamic variablesUse Reflection for a few tasks like statics/enumsThe dynamic keyword in C# makes the formerly most difficult Reflection part - method calls and property assignments - fairly painless. But as cool as dynamic is it doesn't handle all aspects of Reflection. Specifically it doesn't deal with object activation, truly dynamic (string based) member activation or accessing of non instance members, so there's still a little bit of work left to do with Reflection.Dynamic Object InstantiationThe first step in getting the process rolling is to instantiate the type you need to work with. This might be a two step process - loading the instance from a string value, since we don't have a hard type reference and potentially having to load the assembly. Although the host project might have a reference to JSON.NET, that instance might have not been loaded yet since it hasn't been accessed yet. In ASP.NET this won't be a problem, since ASP.NET preloads all referenced assemblies on AppDomain startup, but in other executable project, assemblies are just in time loaded only when they are accessed.Instantiating a type is a two step process: Finding the type reference and then activating it. Here's the generic code out of my ReflectionUtils library I use for this:/// <summary> /// Creates an instance of a type based on a string. Assumes that the type's /// </summary> /// <param name="typeName">Common name of the type</param> /// <param name="args">Any constructor parameters</param> /// <returns></returns> public static object CreateInstanceFromString(string typeName, params object[] args) { object instance = null; Type type = null; try { type = GetTypeFromName(typeName); if (type == null) return null; instance = Activator.CreateInstance(type, args); } catch { return null; } return instance; } /// <summary> /// Helper routine that looks up a type name and tries to retrieve the /// full type reference in the actively executing assemblies. /// </summary> /// <param name="typeName"></param> /// <returns></returns> public static Type GetTypeFromName(string typeName) { Type type = null; // Let default name binding find it type = Type.GetType(typeName, false); if (type != null) return type; // look through assembly list var assemblies = AppDomain.CurrentDomain.GetAssemblies(); // try to find manually foreach (Assembly asm in assemblies) { type = asm.GetType(typeName, false); if (type != null) break; } return type; } To use this for loading JSON.NET I have a small factory function that instantiates JSON.NET and sets a bunch of configuration settings on the generated object. The startup code also looks for failure and tries loading up the assembly when it fails since that's the main reason the load would fail. Finally it also caches the loaded instance for reuse (according to James the JSON.NET instance is thread safe and quite a bit faster when cached). Here's what the factory function looks like in JsonSerializationUtils:/// <summary> /// Dynamically creates an instance of JSON.NET /// </summary> /// <param name="throwExceptions">If true throws exceptions otherwise returns null</param> /// <returns>Dynamic JsonSerializer instance</returns> public static dynamic CreateJsonNet(bool throwExceptions = true) { if (JsonNet != null) return JsonNet; lock (SyncLock) { if (JsonNet != null) return JsonNet; // Try to create instance dynamic json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); if (json == null) { try { var ass = AppDomain.CurrentDomain.Load("Newtonsoft.Json"); json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); } catch (Exception ex) { if (throwExceptions) throw; return null; } } if (json == null) return null; json.ReferenceLoopHandling = (dynamic) ReflectionUtils.GetStaticProperty("Newtonsoft.Json.ReferenceLoopHandling", "Ignore"); // Enums as strings in JSON dynamic enumConverter = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.Converters.StringEnumConverter"); json.Converters.Add(enumConverter); JsonNet = json; } return JsonNet; }This code's purpose is to return a fully configured JsonSerializer instance. As you can see the code tries to create an instance and when it fails tries to load the assembly, and then re-tries loading.Once the instance is loaded some configuration occurs on it. Specifically I set the ReferenceLoopHandling option to not blow up immediately when circular references are encountered. There are a host of other small config setting that might be useful to set, but the default seem to be good enough in recent versions. Note that I'm setting ReferenceLoopHandling which requires an Enum value to be set. There's no real easy way (short of using the cardinal numeric value) to set a property or pass parameters from static values or enums. This means I still need to use Reflection to make this work. I'm using the same ReflectionUtils class I previously used to handle this for me. The function looks up the type and then uses Type.InvokeMember() to read the static property.Another feature I need is have Enum values serialized as strings rather than numeric values which is the default. To do this I can use the StringEnumConverter to convert enums to strings by adding it to the Converters collection.As you can see there's still a bit of Reflection to be done even in C# 4+ with dynamic, but with a few helpers this process is relatively painless.Doing the actual JSON ConversionFinally I need to actually do my JSON conversions. For the Utility class I need serialization that works for both strings and files so I created four methods that handle these tasks two each for serialization and deserialization for string and file.Here's what the File Serialization looks like:/// <summary> /// Serializes an object instance to a JSON file. /// </summary> /// <param name="value">the value to serialize</param> /// <param name="fileName">Full path to the file to write out with JSON.</param> /// <param name="throwExceptions">Determines whether exceptions are thrown or false is returned</param> /// <param name="formatJsonOutput">if true pretty-formats the JSON with line breaks</param> /// <returns>true or false</returns> public static bool SerializeToFile(object value, string fileName, bool throwExceptions = false, bool formatJsonOutput = false) { dynamic writer = null; FileStream fs = null; try { Type type = value.GetType(); var json = CreateJsonNet(throwExceptions); if (json == null) return false; fs = new FileStream(fileName, FileMode.Create); var sw = new StreamWriter(fs, Encoding.UTF8); writer = Activator.CreateInstance(JsonTextWriterType, sw); if (formatJsonOutput) writer.Formatting = (dynamic)Enum.Parse(FormattingType, "Indented"); writer.QuoteChar = '"'; json.Serialize(writer, value); } catch (Exception ex) { Debug.WriteLine("JsonSerializer Serialize error: " + ex.Message); if (throwExceptions) throw; return false; } finally { if (writer != null) writer.Close(); if (fs != null) fs.Close(); } return true; }You can see more of the dynamic invocation in this code. First I grab the dynamic JsonSerializer instance using the CreateJsonNet() method shown earlier which returns a dynamic. I then create a JsonTextWriter and configure a couple of enum settings on it, and then call Serialize() on the serializer instance with the JsonTextWriter that writes the output to disk. Although this code is dynamic it's still fairly short and readable.For full circle operation here's the DeserializeFromFile() version:/// <summary> /// Deserializes an object from file and returns a reference. /// </summary> /// <param name="fileName">name of the file to serialize to</param> /// <param name="objectType">The Type of the object. Use typeof(yourobject class)</param> /// <param name="binarySerialization">determines whether we use Xml or Binary serialization</param> /// <param name="throwExceptions">determines whether failure will throw rather than return null on failure</param> /// <returns>Instance of the deserialized object or null. Must be cast to your object type</returns> public static object DeserializeFromFile(string fileName, Type objectType, bool throwExceptions = false) { dynamic json = CreateJsonNet(throwExceptions); if (json == null) return null; object result = null; dynamic reader = null; FileStream fs = null; try { fs = new FileStream(fileName, FileMode.Open, FileAccess.Read); var sr = new StreamReader(fs, Encoding.UTF8); reader = Activator.CreateInstance(JsonTextReaderType, sr); result = json.Deserialize(reader, objectType); reader.Close(); } catch (Exception ex) { Debug.WriteLine("JsonNetSerialization Deserialization Error: " + ex.Message); if (throwExceptions) throw; return null; } finally { if (reader != null) reader.Close(); if (fs != null) fs.Close(); } return result; }This code is a little more compact since there are no prettifying options to set. Here JsonTextReader is created dynamically and it receives the output from the Deserialize() operation on the serializer.You can take a look at the full JsonSerializationUtils.cs file on GitHub to see the rest of the operations, but the string operations are very similar - the code is fairly repetitive.These generic serialization utilities isolate the dynamic serialization logic that has to deal with the dynamic nature of JSON.NET, and any code that uses these functions is none the wiser that JSON.NET is dynamically loaded.Using the JsonSerializationUtils WrapperThe final consumer of the SerializationUtils wrapper is an actual ConfigurationProvider, that is responsible for handling reading and writing JSON values to and from files. The provider is simple a small wrapper around the SerializationUtils component and there's very little code to make this work now:The whole provider looks like this:/// <summary> /// Reads and Writes configuration settings in .NET config files and /// sections. Allows reading and writing to default or external files /// and specification of the configuration section that settings are /// applied to. /// </summary> public class JsonFileConfigurationProvider<TAppConfiguration> : ConfigurationProviderBase<TAppConfiguration> where TAppConfiguration: AppConfiguration, new() { /// <summary> /// Optional - the Configuration file where configuration settings are /// stored in. If not specified uses the default Configuration Manager /// and its default store. /// </summary> public string JsonConfigurationFile { get { return _JsonConfigurationFile; } set { _JsonConfigurationFile = value; } } private string _JsonConfigurationFile = string.Empty; public override bool Read(AppConfiguration config) { var newConfig = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfiguration)) as TAppConfiguration; if (newConfig == null) { if(Write(config)) return true; return false; } DecryptFields(newConfig); DataUtils.CopyObjectData(newConfig, config, "Provider,ErrorMessage"); return true; } /// <summary> /// Return /// </summary> /// <typeparam name="TAppConfig"></typeparam> /// <returns></returns> public override TAppConfig Read<TAppConfig>() { var result = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfig)) as TAppConfig; if (result != null) DecryptFields(result); return result; } /// <summary> /// Write configuration to XmlConfigurationFile location /// </summary> /// <param name="config"></param> /// <returns></returns> public override bool Write(AppConfiguration config) { EncryptFields(config); bool result = JsonSerializationUtils.SerializeToFile(config, JsonConfigurationFile,false,true); // Have to decrypt again to make sure the properties are readable afterwards DecryptFields(config); return result; } }This incidentally demonstrates how easy it is to create a new provider for the West Wind Application Configuration component. Simply implementing 3 methods will do in most cases.Note this code doesn't have any dynamic dependencies - all that's abstracted away in the JsonSerializationUtils(). From here on, serializing JSON is just a matter of calling the static methods on the SerializationUtils class.Already, there are several other places in some other tools where I use JSON serialization this is coming in very handy. With a couple of lines of code I was able to add JSON.NET support to an older AJAX library that I use replacing quite a bit of code that was previously in use. And for any other manual JSON operations (in a couple of apps I use JSON Serialization for 'blob' like document storage) this is also going to be handy.Performance?Some of you might be thinking that using dynamic and Reflection can't be good for performance. And you'd be right… In performing some informal testing it looks like the performance of the native code is nearly twice as fast as the dynamic code. Most of the slowness is attributable to type lookups. To test I created a native class that uses an actual reference to JSON.NET and performance was consistently around 85-90% faster with the referenced code. This will change though depending on the size of objects serialized - the larger the object the more processing time is spent inside the actual dynamically activated components and the less difference there will be. Dynamic code is always slower, but how much it really affects your application primarily depends on how frequently the dynamic code is called in relation to the non-dynamic code executing. In most situations where dynamic code is used 'to get the process rolling' as I do here the overhead is small enough to not matter.All that being said though - I serialized 10,000 objects in 80ms vs. 45ms so this is hardly slouchy performance. For the configuration component speed is not that important because both read and write operations typically happen once on first access and then every once in a while. But for other operations - say a serializer trying to handle AJAX requests on a Web Server one would be well served to create a hard dependency.Dynamic Loading - Worth it?Dynamic loading is not something you need to worry about but on occasion dynamic loading makes sense. But there's a price to be paid in added code and a performance hit which depends on how frequently the dynamic code is accessed. But for some operations that are not pivotal to a component or application and are only used under certain circumstances dynamic loading can be beneficial to avoid having to ship extra files adding dependencies and loading down distributions. These days when you create new projects in Visual Studio with 30 assemblies before you even add your own code, trying to keep file counts under control seems like a good idea. It's not the kind of thing you do on a regular basis, but when needed it can be a useful option in your toolset… © Rick Strahl, West Wind Technologies, 2005-2013Posted in .NET C# Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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ASP.NET MVC - dropdown list post handling problem

- by ile

I've had troubles for a few days already with handling form that contains dropdown list. I tried all that I've learned so far but nothing helps. This is my code: using System; using System.Collections.Generic; using System.Linq; using System.Web; using CMS; using CMS.Model; using System.ComponentModel.DataAnnotations; namespace Portal.Models { public class ArticleDisplay { public ArticleDisplay() { } public int CategoryID { set; get; } public string CategoryTitle { set; get; } public int ArticleID { set; get; } public string ArticleTitle { set; get; } public DateTime ArticleDate; public string ArticleContent { set; get; } } public class HomePageViewModel { public HomePageViewModel(IEnumerable<ArticleDisplay> summaries, Article article) { this.ArticleSummaries = summaries; this.NewArticle = article; } public IEnumerable<ArticleDisplay> ArticleSummaries { get; private set; } public Article NewArticle { get; private set; } } public class ArticleRepository { private DB db = new DB(); // // Query Methods public IQueryable<ArticleDisplay> FindAllArticles() { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID orderby article.Date descending select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } public IQueryable<ArticleDisplay> FindTodayArticles() { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID where article.Date == DateTime.Today select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } public Article GetArticle(int id) { return db.Articles.SingleOrDefault(d => d.ArticleID == id); } public IQueryable<ArticleDisplay> DetailsArticle(int id) { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID where id == article.ArticleID select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } // // Insert/Delete Methods public void Add(Article article) { db.Articles.InsertOnSubmit(article); } public void Delete(Article article) { db.Articles.DeleteOnSubmit(article); } // // Persistence public void Save() { db.SubmitChanges(); } } } using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using Portal.Models; using CMS.Model; namespace Portal.Areas.CMS.Controllers { public class ArticleController : Controller { ArticleRepository articleRepository = new ArticleRepository(); ArticleCategoryRepository articleCategoryRepository = new ArticleCategoryRepository(); // // GET: /Article/ public ActionResult Index() { ViewData["categories"] = new SelectList ( articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" ); Article article = new Article() { Date = DateTime.Now, CategoryID = 1 }; HomePageViewModel homeData = new HomePageViewModel(articleRepository.FindAllArticles().ToList(), article); return View(homeData); } // // GET: /Article/Details/5 public ActionResult Details(int id) { var article = articleRepository.DetailsArticle(id).Single(); if (article == null) return View("NotFound"); return View(article); } // // GET: /Article/Create //public ActionResult Create() //{ // ViewData["categories"] = new SelectList // ( // articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" // ); // Article article = new Article() // { // Date = DateTime.Now, // CategoryID = 1 // }; // return View(article); //} // // POST: /Article/Create [ValidateInput(false)] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Create(Article article) { if (ModelState.IsValid) { try { // TODO: Add insert logic here articleRepository.Add(article); articleRepository.Save(); return RedirectToAction("Index"); } catch { return View(article); } } else { return View(article); } } // // GET: /Article/Edit/5 public ActionResult Edit(int id) { ViewData["categories"] = new SelectList ( articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" ); var article = articleRepository.GetArticle(id); return View(article); } // // POST: /Article/Edit/5 [ValidateInput(false)] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(int id, FormCollection collection) { Article article = articleRepository.GetArticle(id); try { // TODO: Add update logic here UpdateModel(article, collection.ToValueProvider()); articleRepository.Save(); return RedirectToAction("Details", new { id = article.ArticleID }); } catch { return View(article); } } // // HTTP GET: /Article/Delete/1 public ActionResult Delete(int id) { Article article = articleRepository.GetArticle(id); if (article == null) return View("NotFound"); else return View(article); } // // HTTP POST: /Article/Delete/1 [AcceptVerbs(HttpVerbs.Post)] public ActionResult Delete(int id, string confirmButton) { Article article = articleRepository.GetArticle(id); if (article == null) return View("NotFound"); articleRepository.Delete(article); articleRepository.Save(); return View("Deleted"); } [ValidateInput(false)] public ActionResult UpdateSettings(int id, string value, string field) { // This highly-specific example is from the original coder's blog system, // but you can substitute your own code here. I assume you can pick out // which text field it is from the id. Article article = articleRepository.GetArticle(id); if (article == null) return Content("Error"); if (field == "Title") { article.Title = value; UpdateModel(article, new[] { "Title" }); articleRepository.Save(); } if (field == "Content") { article.Content = value; UpdateModel(article, new[] { "Content" }); articleRepository.Save(); } if (field == "Date") { article.Date = Convert.ToDateTime(value); UpdateModel(article, new[] { "Date" }); articleRepository.Save(); } return Content(value); } } } and view: <%@ Page Title="" Language="C#" MasterPageFile="~/Areas/CMS/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<Portal.Models.HomePageViewModel>" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Index </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <div class="naslov_poglavlja_main">Articles Administration</div> <%= Html.ValidationSummary("Create was unsuccessful. Please correct the errors and try again.") %> <% using (Html.BeginForm("Create","Article")) {%> <div class="news_forma"> <label for="Title" class="news">Title:</label> <%= Html.TextBox("Title", "", new { @class = "news" })%> <%= Html.ValidationMessage("Title", "*") %> <label for="Content" class="news">Content:</label> <div class="textarea_okvir"> <%= Html.TextArea("Content", "", new { @class = "news" })%> <%= Html.ValidationMessage("Content", "*")%> </div> <label for="CategoryID" class="news">Category:</label> <%= Html.DropDownList("CategoryId", (IEnumerable<SelectListItem>)ViewData["categories"], new { @class = "news" })%> <p> <input type="submit" value="Publish" class="form_submit" /> </p> </div> <% } %> <div class="naslov_poglavlja_main"><%= Html.ActionLink("Write new article...", "Create") %></div> <div id="articles"> <% foreach (var item in Model.ArticleSummaries) { %> <div> <div class="naslov_vijesti" id="<%= item.ArticleID %>"><%= Html.Encode(item.ArticleTitle) %></div> <div class="okvir_vijesti"> <div class="sadrzaj_vijesti" id="<%= item.ArticleID %>"><%= item.ArticleContent %></div> <div class="datum_vijesti" id="<%= item.ArticleID %>"><%= Html.Encode(String.Format("{0:g}", item.ArticleDate)) %></div> <a class="news_delete" href="#" id="<%= item.ArticleID %>">Delete</a> </div> <div class="dno"></div> </div> <% } %> </div> </asp:Content> When trying to post new article I get following error: System.InvalidOperationException: The ViewData item that has the key 'CategoryId' is of type 'System.Int32' but must be of type 'IEnumerable'. I really don't know what to do cause I'm pretty new to .net and mvc Any help appreciated! Ile EDIT: I found where I made mistake. I didn't include date. If in view form I add this line I'm able to add article: <%=Html.Hidden("Date", String.Format("{0:g}", Model.NewArticle.Date)) %> But, if I enter wrong datetype or leave title and content empty then I get the same error. In this eample there is no need for date edit, but I will need it for some other forms and validation will be necessary. EDIT 2: Error happens when posting! Call stack: App_Web_of9beco9.dll!ASP.areas_cms_views_article_create_aspx.__RenderContent2(System.Web.UI.HtmlTextWriter __w = {System.Web.UI.HtmlTextWriter}, System.Web.UI.Control parameterContainer = {System.Web.UI.WebControls.ContentPlaceHolder}) Line 31 + 0x9f bytes C#

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Optimizing a lot of Scanner.findWithinHorizon(pattern, 0) calls

- by darvids0n

I'm building a process which extracts data from 6 csv-style files and two poorly laid out .txt reports and builds output CSVs, and I'm fully aware that there's going to be some overhead searching through all that whitespace thousands of times, but I never anticipated converting about about 50,000 records would take 12 hours. Excerpt of my manual matching code (I know it's horrible that I use lists of tokens like that, but it was the best thing I could think of): public static String lookup(List<String> tokensBefore, List<String> tokensAfter) { String result = null; while(_match(tokensBefore)) { // block until all input is read if(id.hasNext()) { result = id.next(); // capture the next token that matches if(_matchImmediate(tokensAfter)) // try to match tokensAfter to this result return result; } else return null; // end of file; no match } return null; // no matches } private static boolean _match(List<String> tokens) { return _match(tokens, true); } private static boolean _match(List<String> tokens, boolean block) { if(tokens != null && !tokens.isEmpty()) { if(id.findWithinHorizon(tokens.get(0), 0) == null) return false; for(int i = 1; i <= tokens.size(); i++) { if (i == tokens.size()) { // matches all tokens return true; } else if(id.hasNext() && !id.next().matches(tokens.get(i))) { break; // break to blocking behaviour } } } else { return true; // empty list always matches } if(block) return _match(tokens); // loop until we find something or nothing else return false; // return after just one attempted match } private static boolean _matchImmediate(List<String> tokens) { if(tokens != null) { for(int i = 0; i <= tokens.size(); i++) { if (i == tokens.size()) { // matches all tokens return true; } else if(!id.hasNext() || !id.next().matches(tokens.get(i))) { return false; // doesn't match, or end of file } } return false; // we have some serious problems if this ever gets called } else { return true; // empty list always matches } } Basically wondering how I would work in an efficient string search (Boyer-Moore or similar). My Scanner id is scanning a java.util.String, figured buffering it to memory would reduce I/O since the search here is being performed thousands of times on a relatively small file. The performance increase compared to scanning a BufferedReader(FileReader(File)) was probably less than 1%, the process still looks to be taking a LONG time. I've also traced execution and the slowness of my overall conversion process is definitely between the first and last like of the lookup method. In fact, so much so that I ran a shortcut process to count the number of occurrences of various identifiers in the .csv-style files (I use 2 lookup methods, this is just one of them) and the process completed indexing approx 4 different identifiers for 50,000 records in less than a minute. Compared to 12 hours, that's instant. Some notes (updated): I don't necessarily need the pattern-matching behaviour, I only get the first field of a line of text so I need to match line breaks or use Scanner.nextLine(). All ID numbers I need start at position 0 of a line and run through til the first block of whitespace, after which is the name of the corresponding object. I would ideally want to return a String, not an int locating the line number or start position of the result, but if it's faster then it will still work just fine. If an int is being returned, however, then I would now have to seek to that line again just to get the ID; storing the ID of every line that is searched sounds like a way around that. Anything to help me out, even if it saves 1ms per search, will help, so all input is appreciated. Thankyou! Usage scenario 1: I have a list of objects in file A, who in the old-style system have an id number which is not in file A. It is, however, POSSIBLY in another csv-style file (file B) or possibly still in a .txt report (file C) which each also contain a bunch of other information which is not useful here, and so file B needs to be searched through for the object's full name (1 token since it would reside within the second column of any given line), and then the first column should be the ID number. If that doesn't work, we then have to split the search token by whitespace into separate tokens before doing a search of file C for those tokens as well. Generalised code: String field; for (/* each record in file A */) { /* construct the rest of this object from file A info */ // now to find the ID, if we can List<String> objectName = new ArrayList<String>(1); objectName.add(Pattern.quote(thisObject.fullName)); field = lookup(objectSearchToken, objectName); // search file B if(field == null) // not found in file B { lookupReset(false); // initialise scanner to check file C objectName.clear(); // not using the full name String[] tokens = thisObject.fullName.split(id.delimiter().pattern()); for(String s : tokens) objectName.add(Pattern.quote(s)); field = lookup(objectSearchToken, objectName); // search file C lookupReset(true); // back to file B } else { /* found it, file B specific processing here */ } if(field != null) // found it in B or C thisObject.ID = field; } The objectName tokens are all uppercase words with possible hyphens or apostrophes in them, separated by spaces. Much like a person's name. As per a comment, I will pre-compile the regex for my objectSearchToken, which is just [\r\n]+. What's ending up happening in file C is, every single line is being checked, even the 95% of lines which don't contain an ID number and object name at the start. Would it be quicker to use ^[\r\n]+.*(objectname) instead of two separate regexes? It may reduce the number of _match executions. The more general case of that would be, concatenate all tokensBefore with all tokensAfter, and put a .* in the middle. It would need to be matching backwards through the file though, otherwise it would match the correct line but with a huge .* block in the middle with lots of lines. The above situation could be resolved if I could get java.util.Scanner to return the token previous to the current one after a call to findWithinHorizon. I have another usage scenario. Will put it up asap.

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PHP contact form font color is stuck to black

- by Richard Hayward

No matter what i try strangely enough my form and thank you page both php files one with embed font coloring and one with an external style sheet refuse to change font color from black. thank you php file: http://www.richiesportfolio.com/contact/thank-you.php contact form php file: http://www.richiesportfolio.com/contact/contactform.php Everything else works purfectly but changing the contact forms font color contactform.php ` <?PHP require_once("./include/fgcontactform.php"); $formproc = new FGContactForm(); if(isset($_POST['submitted'])) { if($formproc->ProcessForm()) { $formproc->RedirectToURL("thank-you.php"); } } ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US" lang="en-US"> <head> <meta http-equiv='Content-Type' content='text/html; charset=utf-8'/> <title>Contact us</title> <link rel="stylesheet" type="text/css" href="http://www.richiesportfolio.com/contact/contact.css" /> <script type='text/javascript' src='scripts/gen_validatorv31.js'></script> </head> <body>  <form id='contactus' action='<?php echo $formproc->GetSelfScript(); ?>' method='post' accept-charset='UTF-8'> <fieldset > <legend>Contact Me</legend> <input type='hidden' name='submitted' id='submitted' value='1'/> <input type='hidden' name='<?php echo $formproc->GetFormIDInputName(); ?>' value='<?php echo $formproc->GetFormIDInputValue(); ?>'/> <input type='text' class='spmhidip' name='<?php echo $formproc->GetSpamTrapInputName(); ?>' /> <div class='short_explanation'>* required fields</div> <div><span class='error'><?php echo $formproc->GetErrorMessage(); ?></span></div> <div class='container'> <label for='name' >Your Full Name*: </label><br/> <input type='text' name='name' id='name' value='<?php echo $formproc->SafeDisplay('name') ?>' maxlength="50" /><br/> <span id='contactus_name_errorloc' class='error'></span> </div> <div class='container'> <label for='email' >Email Address*:</label><br/> <input type='text' name='email' id='email' value='<?php echo $formproc->SafeDisplay('email') ?>' maxlength="50" /><br/> <span id='contactus_email_errorloc' class='error'></span> </div> <div class='container'> <label for='message' >Message:</label><br/> <span id='contactus_message_errorloc' class='error'></span> <textarea rows="10" cols="50" name='message' id='message'><?php echo $formproc->SafeDisplay('message') ?></textarea> </div> <div class='container'> <input type='submit' name='Submit' value='Submit' /> </div> </fieldset> </form>  <script type='text/javascript'> // <![CDATA[ var frmvalidator = new Validator("contactus"); frmvalidator.EnableOnPageErrorDisplay(); frmvalidator.EnableMsgsTogether(); frmvalidator.addValidation("name","req","Please provide your name"); frmvalidator.addValidation("email","req","Please provide your email address"); frmvalidator.addValidation("email","email","Please provide a valid email address"); frmvalidator.addValidation("message","maxlen=2048","The message is too long!(more than 2KB!)"); // ]]> </script> </body> </html>` contact.css body,table,tr,td,a,p,h1,h2,h3,h4,h5,input,h3 a,h4 a,h5 ul, li, ul, a { color:#FFF; } #contactus fieldset { width:320px; padding:20px; border:20px; -moz-border-radius: 10px; -webkit-border-radius: 10px; -khtml-border-radius: 10px; border-radius: 10px; } #contactus legend, h2 { font-family : Arial, sans-serif; font-size:1.3em; font-weight:bold; color:#FFF; } #contactus label { font-family : Arial, sans-serif; font-size:0.8em; font-weight: bold; color:#FFF; } #contactus input[type="text"],textarea { font-family : Arial, Verdana, sans-serif; font-size: 0.8em; line-height:140%; color : #000; padding : 3px; border : 1px solid; #999; -moz-border-radius: 5px; -webkit-border-radius: 5px; -khtml-border-radius: 5px; border-radius: 5px; } #contactus input[type="text"] { height:18px; width:220px; -webkit-border-radius: 5px; -moz-border-radius: 5px; border-radius: 5px; } #contactus #scaptcha { width:60px; height:18px; } #contactus input[type="submit"] { width:100px; height:30px; padding-left:0px; -webkit-border-radius: 5px; -moz-border-radius: 5px; border-radius: 5px; } #contactus textarea { height:120px; width:310px; -webkit-border-radius:8px; -moz-border-radius: 8px; border-radius: 8px; } #contactus input[type="text"]:focus,textarea:focus { color : #009; border : 1px solid #990000; background-color : #ffff99; font-weight:bold; } #contactus .container { margin-top:8px; margin-bottom:10px; color:#FFF; } #contactus .error { font-family: Verdana, Arial, sans-serif; font-size: 0.7em; color: #900; background-color : #111; } #contactus fieldset#antispam { padding:2px; border-top:1px solid #EEE; border-left:0; border-right:0; border-bottom:0; width:350px; } #contactus fieldset#antispam legend { font-family : Arial, sans-serif; font-size: 0.8em; font-weight:bold; color:#FFF; } #contactus .short_explanation { font-family : Arial, sans-serif; font-size: 0.6em; color:#FFF; } /* spam_trap: This input is hidden. This is here to trick the spam bots*/ #contactus .spmhidip { display:none; width:10px; height:3px; } #fg_crdiv { font-family : Arial, sans-serif; font-size: 0.3em; opacity: .2; -moz-opacity: .2; filter: alpha(opacity=20); } #fg_crdiv p { display:none; }

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Suggestions for duplicate file finder algorithm (using C)

- by Andrei Ciobanu

Hello, I wanted to write a program that test if two files are duplicates (have exactly the same content). First I test if the files have the same sizes, and if they have i start to compare their contents. My first idea, was to "split" the files into fixed size blocks, then start a thread for every block, fseek to startup character of every block and continue the comparisons in parallel. When a comparison from a thread fails, the other working threads are canceled, and the program exits out of the thread spawning loop. The code looks like this: dupf.h #ifndef __NM__DUPF__H__ #define __NM__DUPF__H__ #define NUM_THREADS 15 #define BLOCK_SIZE 8192 /* Thread argument structure */ struct thread_arg_s { const char *name_f1; /* First file name */ const char *name_f2; /* Second file name */ int cursor; /* Where to seek in the file */ }; typedef struct thread_arg_s thread_arg; /** * 'arg' is of type thread_arg. * Checks if the specified file blocks are * duplicates. */ void *check_block_dup(void *arg); /** * Checks if two files are duplicates */ int check_dup(const char *name_f1, const char *name_f2); /** * Returns a valid pointer to a file. * If the file (given by the path/name 'fname') cannot be opened * in 'mode', the program is interrupted an error message is shown. **/ FILE *safe_fopen(const char *name, const char *mode); #endif dupf.c #include <errno.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include "dupf.h" FILE *safe_fopen(const char *fname, const char *mode) { FILE *f = NULL; f = fopen(fname, mode); if (f == NULL) { char emsg[255]; sprintf(emsg, "FOPEN() %s\t", fname); perror(emsg); exit(-1); } return (f); } void *check_block_dup(void *arg) { const char *name_f1 = NULL, *name_f2 = NULL; /* File names */ FILE *f1 = NULL, *f2 = NULL; /* Streams */ int cursor = 0; /* Reading cursor */ char buff_f1[BLOCK_SIZE], buff_f2[BLOCK_SIZE]; /* Character buffers */ int rchars_1, rchars_2; /* Readed characters */ /* Initializing variables from 'arg' */ name_f1 = ((thread_arg*)arg)->name_f1; name_f2 = ((thread_arg*)arg)->name_f2; cursor = ((thread_arg*)arg)->cursor; /* Opening files */ f1 = safe_fopen(name_f1, "r"); f2 = safe_fopen(name_f2, "r"); /* Setup cursor in files */ fseek(f1, cursor, SEEK_SET); fseek(f2, cursor, SEEK_SET); /* Initialize buffers */ rchars_1 = fread(buff_f1, 1, BLOCK_SIZE, f1); rchars_2 = fread(buff_f2, 1, BLOCK_SIZE, f2); if (rchars_1 != rchars_2) { /* fread failed to read the same portion. * program cannot continue */ perror("ERROR WHEN READING BLOCK"); exit(-1); } while (rchars_1-->0) { if (buff_f1[rchars_1] != buff_f2[rchars_1]) { /* Different characters */ fclose(f1); fclose(f2); pthread_exit("notdup"); } } /* Close streams */ fclose(f1); fclose(f2); pthread_exit("dup"); } int check_dup(const char *name_f1, const char *name_f2) { int num_blocks = 0; /* Number of 'blocks' to check */ int num_tsp = 0; /* Number of threads spawns */ int tsp_iter = 0; /* Iterator for threads spawns */ pthread_t *tsp_threads = NULL; thread_arg *tsp_threads_args = NULL; int tsp_threads_iter = 0; int thread_c_res = 0; /* Thread creation result */ int thread_j_res = 0; /* Thread join res */ int loop_res = 0; /* Function result */ int cursor; struct stat buf_f1; struct stat buf_f2; if (name_f1 == NULL || name_f2 == NULL) { /* Invalid input parameters */ perror("INVALID FNAMES\t"); return (-1); } if (stat(name_f1, &buf_f1) != 0 || stat(name_f2, &buf_f2) != 0) { /* Stat fails */ char emsg[255]; sprintf(emsg, "STAT() ERROR: %s %s\t", name_f1, name_f2); perror(emsg); return (-1); } if (buf_f1.st_size != buf_f2.st_size) { /* File have different sizes */ return (1); } /* Files have the same size, function exec. is continued */ num_blocks = (buf_f1.st_size / BLOCK_SIZE) + 1; num_tsp = (num_blocks / NUM_THREADS) + 1; cursor = 0; for (tsp_iter = 0; tsp_iter < num_tsp; tsp_iter++) { loop_res = 0; /* Create threads array for this spawn */ tsp_threads = malloc(NUM_THREADS * sizeof(*tsp_threads)); if (tsp_threads == NULL) { perror("TSP_THREADS ALLOC FAILURE\t"); return (-1); } /* Create arguments for every thread in the current spawn */ tsp_threads_args = malloc(NUM_THREADS * sizeof(*tsp_threads_args)); if (tsp_threads_args == NULL) { perror("TSP THREADS ARGS ALLOCA FAILURE\t"); return (-1); } /* Initialize arguments and create threads */ for (tsp_threads_iter = 0; tsp_threads_iter < NUM_THREADS; tsp_threads_iter++) { if (cursor >= buf_f1.st_size) { break; } tsp_threads_args[tsp_threads_iter].name_f1 = name_f1; tsp_threads_args[tsp_threads_iter].name_f2 = name_f2; tsp_threads_args[tsp_threads_iter].cursor = cursor; thread_c_res = pthread_create( &tsp_threads[tsp_threads_iter], NULL, check_block_dup, (void*)&tsp_threads_args[tsp_threads_iter]); if (thread_c_res != 0) { perror("THREAD CREATION FAILURE"); return (-1); } cursor+=BLOCK_SIZE; } /* Join last threads and get their status */ while (tsp_threads_iter-->0) { void *thread_res = NULL; thread_j_res = pthread_join(tsp_threads[tsp_threads_iter], &thread_res); if (thread_j_res != 0) { perror("THREAD JOIN FAILURE"); return (-1); } if (strcmp((char*)thread_res, "notdup")==0) { loop_res++; /* Closing other threads and exiting by condition * from loop. */ while (tsp_threads_iter-->0) { pthread_cancel(tsp_threads[tsp_threads_iter]); } } } free(tsp_threads); free(tsp_threads_args); if (loop_res > 0) { break; } } return (loop_res > 0) ? 1 : 0; } The function works fine (at least for what I've tested). Still, some guys from #C (freenode) suggested that the solution is overly complicated, and it may perform poorly because of parallel reading on hddisk. What I want to know: Is the threaded approach flawed by default ? Is fseek() so slow ? Is there a way to somehow map the files to memory and then compare them ?

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OBJ model loaded in LWJGL has a black area with no texture

- by gambiting

I have a problem with loading an .obj file in LWJGL and its textures. The object is a tree(it's a paid model from TurboSquid, so I can't post it here,but here's the link if you want to see how it should look like): http://www.turbosquid.com/FullPreview/Index.cfm/ID/701294 I wrote a custom OBJ loader using the LWJGL tutorial from their wiki. It looks like this: public class OBJLoader { public static Model loadModel(File f) throws FileNotFoundException, IOException { BufferedReader reader = new BufferedReader(new FileReader(f)); Model m = new Model(); String line; Texture currentTexture = null; while((line=reader.readLine()) != null) { if(line.startsWith("v ")) { float x = Float.valueOf(line.split(" ")[1]); float y = Float.valueOf(line.split(" ")[2]); float z = Float.valueOf(line.split(" ")[3]); m.verticies.add(new Vector3f(x,y,z)); }else if(line.startsWith("vn ")) { float x = Float.valueOf(line.split(" ")[1]); float y = Float.valueOf(line.split(" ")[2]); float z = Float.valueOf(line.split(" ")[3]); m.normals.add(new Vector3f(x,y,z)); }else if(line.startsWith("vt ")) { float x = Float.valueOf(line.split(" ")[1]); float y = Float.valueOf(line.split(" ")[2]); m.texVerticies.add(new Vector2f(x,y)); }else if(line.startsWith("f ")) { Vector3f vertexIndicies = new Vector3f(Float.valueOf(line.split(" ")[1].split("/")[0]), Float.valueOf(line.split(" ")[2].split("/")[0]), Float.valueOf(line.split(" ")[3].split("/")[0])); Vector3f textureIndicies = new Vector3f(Float.valueOf(line.split(" ")[1].split("/")[1]), Float.valueOf(line.split(" ")[2].split("/")[1]), Float.valueOf(line.split(" ")[3].split("/")[1])); Vector3f normalIndicies = new Vector3f(Float.valueOf(line.split(" ")[1].split("/")[2]), Float.valueOf(line.split(" ")[2].split("/")[2]), Float.valueOf(line.split(" ")[3].split("/")[2])); m.faces.add(new Face(vertexIndicies,textureIndicies,normalIndicies,currentTexture.getTextureID())); }else if(line.startsWith("g ")) { if(line.length()>2) { String name = line.split(" ")[1]; currentTexture = TextureLoader.getTexture("PNG", ResourceLoader.getResourceAsStream("res/" + name + ".png")); System.out.println(currentTexture.getTextureID()); } } } reader.close(); System.out.println(m.verticies.size() + " verticies"); System.out.println(m.normals.size() + " normals"); System.out.println(m.texVerticies.size() + " texture coordinates"); System.out.println(m.faces.size() + " faces"); return m; } } Then I create a display list for my model using this code: objectDisplayList = GL11.glGenLists(1); GL11.glNewList(objectDisplayList, GL11.GL_COMPILE); Model m = null; try { m = OBJLoader.loadModel(new File("res/untitled4.obj")); } catch (Exception e1) { e1.printStackTrace(); } int currentTexture=0; for(Face face: m.faces) { if(face.texture!=currentTexture) { currentTexture = face.texture; GL11.glBindTexture(GL11.GL_TEXTURE_2D, currentTexture); } GL11.glColor3f(1f, 1f, 1f); GL11.glBegin(GL11.GL_TRIANGLES); Vector3f n1 = m.normals.get((int) face.normal.x - 1); GL11.glNormal3f(n1.x, n1.y, n1.z); Vector2f t1 = m.texVerticies.get((int) face.textures.x -1); GL11.glTexCoord2f(t1.x, t1.y); Vector3f v1 = m.verticies.get((int) face.vertex.x - 1); GL11.glVertex3f(v1.x, v1.y, v1.z); Vector3f n2 = m.normals.get((int) face.normal.y - 1); GL11.glNormal3f(n2.x, n2.y, n2.z); Vector2f t2 = m.texVerticies.get((int) face.textures.y -1); GL11.glTexCoord2f(t2.x, t2.y); Vector3f v2 = m.verticies.get((int) face.vertex.y - 1); GL11.glVertex3f(v2.x, v2.y, v2.z); Vector3f n3 = m.normals.get((int) face.normal.z - 1); GL11.glNormal3f(n3.x, n3.y, n3.z); Vector2f t3 = m.texVerticies.get((int) face.textures.z -1); GL11.glTexCoord2f(t3.x, t3.y); Vector3f v3 = m.verticies.get((int) face.vertex.z - 1); GL11.glVertex3f(v3.x, v3.y, v3.z); GL11.glEnd(); } GL11.glEndList(); The currentTexture is an int - it contains the ID of the currently used texture. So my model looks absolutely fine without textures: (sorry I cannot post hyperlinks since I am a new user) i.imgur.com/VtoK0.png But look what happens if I enable GL_TEXTURE_2D: i.imgur.com/z8Kli.png i.imgur.com/5e9nn.png i.imgur.com/FAHM9.png As you can see an entire side of the tree appears to be missing - and it's not transparent, since it's not in the colour of the background - it's rendered black. It's not a problem with the model - if I load it using Kanji's OBJ loader it works fine(but the thing is,that I need to write my own OBJ loader) i.imgur.com/YDATo.png this is my OpenGL init section: //init display try { Display.setDisplayMode(new DisplayMode(Support.SCREEN_WIDTH, Support.SCREEN_HEIGHT)); Display.create(); Display.setVSyncEnabled(true); } catch (LWJGLException e) { e.printStackTrace(); System.exit(0); } GL11.glLoadIdentity(); GL11.glEnable(GL11.GL_TEXTURE_2D); GL11.glClearColor(1.0f, 0.0f, 0.0f, 1.0f); GL11.glShadeModel(GL11.GL_SMOOTH); GL11.glEnable(GL11.GL_DEPTH_TEST); GL11.glDepthFunc(GL11.GL_LESS); GL11.glDepthMask(true); GL11.glEnable(GL11.GL_NORMALIZE); GL11.glMatrixMode(GL11.GL_PROJECTION); GLU.gluPerspective (90.0f,800f/600f, 1f, 500.0f); GL11.glMatrixMode(GL11.GL_MODELVIEW); GL11.glEnable(GL11.GL_CULL_FACE); GL11.glCullFace(GL11.GL_BACK); //enable lighting GL11.glEnable(GL11.GL_LIGHTING); ByteBuffer temp = ByteBuffer.allocateDirect(16); temp.order(ByteOrder.nativeOrder()); GL11.glMaterial(GL11.GL_FRONT, GL11.GL_DIFFUSE, (FloatBuffer)temp.asFloatBuffer().put(lightDiffuse).flip()); GL11.glMaterialf(GL11.GL_FRONT, GL11.GL_SHININESS,(int)material_shinyness); GL11.glLight(GL11.GL_LIGHT2, GL11.GL_DIFFUSE, (FloatBuffer)temp.asFloatBuffer().put(lightDiffuse2).flip()); // Setup The Diffuse Light GL11.glLight(GL11.GL_LIGHT2, GL11.GL_POSITION,(FloatBuffer)temp.asFloatBuffer().put(lightPosition2).flip()); GL11.glLight(GL11.GL_LIGHT2, GL11.GL_AMBIENT,(FloatBuffer)temp.asFloatBuffer().put(lightAmbient).flip()); GL11.glLight(GL11.GL_LIGHT2, GL11.GL_SPECULAR,(FloatBuffer)temp.asFloatBuffer().put(lightDiffuse2).flip()); GL11.glLightf(GL11.GL_LIGHT2, GL11.GL_CONSTANT_ATTENUATION, 0.1f); GL11.glLightf(GL11.GL_LIGHT2, GL11.GL_LINEAR_ATTENUATION, 0.0f); GL11.glLightf(GL11.GL_LIGHT2, GL11.GL_QUADRATIC_ATTENUATION, 0.0f); GL11.glEnable(GL11.GL_LIGHT2); Could somebody please help me?

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xml to xsl transformation

- by amirin

Hi, I have a requirement to extract the uniquie values from the different nodes of the given xml using xsl transformation. XML FILE:- var IPClaimCausesNice = ""; function changeIPClaimCause(){ if(CommJob.client.policy.Insurance.Coverages.Coverage[0].Claim.IPClaimCause == "Diagnosis") { IPClaimCausesNice = "diagnosis" } if(CommJob.client.policy.Insurance.Coverages.Coverage[0].Claim.IPClaimCause == "Illness") { IPClaimCausesNice = "illness" } if(CommJob.client.policy.Insurance.Coverages.Coverage[0].Claim.IPClaimCause == "Accident") { IPClaimCausesNice = "accident" } return IPClaimCausesNice; } <section id="1903879316" name="Logos"> <fraglink id="605609862" resid="1235000151"> <argvalue name="CommJob"> <var name="CommJob" type="Th_1235001170_CommJob" /> </argvalue> </fraglink> </section> <section id="13483397" name="Address Block"> <fraglink id="563800610" resid="986000123"> <argvalue name="PersonInformation"> <var name="AddresseePersonInformation" type="Th_1235000929_PersonInformation" /> </argvalue> </fraglink> </section> <section id="1093480468" name="Details"> <fraglink id="460316501" resid="1195000163"> <argvalue name="currentDateTime"> <var name="getSystemVariables.getCurrentDate" type="date" /> </argvalue> <argvalue name="CommJob"> <var name="CommJob" type="Th_1235000929_CommJob" /> </argvalue> <argvalue name="ShowDOB" /> <argvalue name="ShowYourRef" /> <argvalue name="YourRefLabel" /> </fraglink> <fraglink id="1026044336" resid="1235000070"> <argvalue name="brandKey"> <var name="CommJob.commJobDetails.brandingKey" type="string" /> </argvalue> <argvalue name="brandSponsor"> <var name="CommJob.client.policy.policyDetails.brandSponsor" type="string" /> </argvalue> </fraglink> </section> <section id="2092948772" name="Important info"> <frag id="1180564368" name="frag" no-match="error" type="text"> <edition id="1178777425" name="Any" withdrawn="False"> <edition-content> <p style="bodyTableHeader" align="left" xml:space="preserve">Important information</p> <p style="body" xml:space="preserve">In accordance with the terms and conditions of your policy, your claim has been classified as a <iif><expression><script language="JavaScript">CommJob.client.policy.Insurance.Coverages.Coverage[0].Claim.IPClaimCause == "Diagnosis" || CommJob.client.policy.Insurance.Coverages.Coverage[0].Claim.IPClaimCause == "Ill health"</script><description>the IPClaimCause of the CommJob's client policy insurances Insurance Coverages IPCover Claim equals "Diagnosis" or the IPClaimCause of the CommJob's client policy insurances Insurance Coverages IPCover Claim equals "Ill health"sicknessCommJob.client.policy.Insurance.Coverages.Coverage[0].Claim.IPClaimCause == "Accident"the IPClaimCause of the CommJob's client policy insurances Insurance Coverages IPCover Claim equals "Accident"accident. Please assist us Please quote your policy and claim numbers / when returning your forms. Your claim has been received Your Thank you for sending your Initial Claim Form which we received on . We are sorry to hear of your recent . Our assessmentThe attending doctor’s statement indicates you are claiming benefits as a result of , CommJob.client.policy.Insurance.Coverages.Coverage[0].Claim.IPClaimCause == "Diagnosis"the IPClaimCause of the CommJob's client policy Insurance Coverages first Coverage Claim equals "Diagnosis"which was diagnosedCommJob.client.policy.Insurance.Coverages.Coverage[0].Claim.IPClaimCause == "Accident"the IPClaimCause of the CommJob's client policy Insurance Coverages first Coverage Claim equals "Accident"which first occuredCommJob.client.policy.Insurance.Coverages.Coverage[0].Claim.IPClaimCause == "Ill health"the IPClaimCause of the CommJob's client policy Insurance Coverages first Coverage Claim equals "Ill health"with symptoms commencing on . We note you ceased all work on and consulted your doctor IsNotMissing(CommJob.placeHolders.date.date5)the date5 of the CommJob's placeHolders date is not missingon this day also regarding your condition. Further information is required We’ve enclosed the following forms. Please complete these and return them to us so that we can continue assessing your claim. Progress claim form Attached questionnaire Authority to the Health Insurance Commission Medical authority <<other/ free format>> <<other/ free format>> Please be advised we’ve CommJob.placeHolders._boolean.boolean1 == truethe CommJob's placeHolders boolean is boolean1also requested the following information: Medical report from Dr Medicare history report from the Health Insurance Commission <<other/ free format>> <<other/ free format>> As your claim forms have been submitted months after you ceased work, our ability to properly assess your claim may have been prejudiced. In order to complete our assessment of your claim, the following information is required within 30 days of this letter: Reason for late lodgement of claim. Reason(s) you ceased work on (eg redundancy or due to medical condition). Name and contact details of all doctors and specialists you have consulted since you ceased work. Copies of any medical, radiology, pathology or other reports in your possession. Details of all treatment you have received since you ceased work. Whether you returned to work (paid or unpaid) in either a full-time or part-time capacity. If so, please provide the dates you worked, hours you worked, duties you performed and any income you received. Financial information for any other related entities (if applicable). If you are unable to supply the above information, please contact us by WriteText(FormatDateTime(DateAdd(getSystemVariables.getCurrentDate,"day",30),"dd MMMM yyyy")). To help in the ongoing assessment of your claim, you are required to be under the regular care and attendance of a medical practitioner. We’ve enclosed a Progress Claim Form which needs to be completed and returned to us by . False False False CC: Different nodes to pick the values:- 1. 2.path form 5. Values to be picked form the xml node and display in HTML is like CommJob.client.policy.Insurance.Coverages.Coverage[0].Claim.IPClaimCause CommJob.commJobDetails.stockType CommJob.commJobDetails.targetClient.targetClientName CommJob.client.policy.policyDetails.policyStatus CommJob.client.policy.policyDetails.productType CommJob.commJobDetails.targetClient.targetClientName ........etc can any one help me to provide the solution. This xsl transformation doesn't pick correctly only the values <xsl:template match="@*"/> Any help on this will great.

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Mysql - help me optimize this query

- by sandeepan-nath

About the system: -The system has a total of 8 tables - Users - Tutor_Details (Tutors are a type of User,Tutor_Details table is linked to Users) - learning_packs, (stores packs created by tutors) - learning_packs_tag_relations, (holds tag relations meant for search) - tutors_tag_relations and tags and orders (containing purchase details of tutor's packs), order_details linked to orders and tutor_details. For a more clear idea about the tables involved please check the The tables section in the end. -A tags based search approach is being followed.Tag relations are created when new tutors register and when tutors create packs (this makes tutors and packs searcheable). For details please check the section How tags work in this system? below. Following is a simpler representation (not the actual) of the more complex query which I am trying to optimize:- I have used statements like explanation of parts in the query select SUM(DISTINCT( t.tag LIKE "%Dictatorship%" )) as key_1_total_matches, SUM(DISTINCT( t.tag LIKE "%democracy%" )) as key_2_total_matches, td., u., count(distinct(od.id_od)), if (lp.id_lp > 0) then some conditional logic on lp fields else 0 as tutor_popularity from Tutor_Details AS td JOIN Users as u on u.id_user = td.id_user LEFT JOIN Learning_Packs_Tag_Relations AS lptagrels ON td.id_tutor = lptagrels.id_tutor LEFT JOIN Learning_Packs AS lp ON lptagrels.id_lp = lp.id_lp LEFT JOIN `some other tables on lp.id_lp - let's call learning pack tables set (including Learning_Packs table)` LEFT JOIN Order_Details as od on td.id_tutor = od.id_author LEFT JOIN Orders as o on od.id_order = o.id_order LEFT JOIN Tutors_Tag_Relations as ttagrels ON td.id_tutor = ttagrels.id_tutor JOIN Tags as t on (t.id_tag = ttagrels.id_tag) OR (t.id_tag = lptagrels.id_tag) where some condition on Users table's fields AND CASE WHEN ((t.id_tag = lptagrels.id_tag) AND (lp.id_lp 0)) THEN `some conditions on learning pack tables set` ELSE 1 END AND CASE WHEN ((t.id_tag = wtagrels.id_tag) AND (wc.id_wc 0)) THEN `some conditions on webclasses tables set` ELSE 1 END AND CASE WHEN (od.id_od0) THEN od.id_author = td.id_tutor and some conditions on Orders table's fields ELSE 1 END AND ( t.tag LIKE "%Dictatorship%" OR t.tag LIKE "%democracy%") group by td.id_tutor HAVING key_1_total_matches = 1 AND key_2_total_matches = 1 order by tutor_popularity desc, u.surname asc, u.name asc limit 0,20 ===================================================================== What does the above query do? Does AND logic search on the search keywords (2 in this example - "Democracy" and "Dictatorship"). Returns only those tutors for which both the keywords are present in the union of the two sets - tutors details and details of all the packs created by a tutor. To make things clear - Suppose a Tutor name "Sandeepan Nath" has created a pack "My first pack", then:- Searching "Sandeepan Nath" returns Sandeepan Nath. Searching "Sandeepan first" returns Sandeepan Nath. Searching "Sandeepan second" does not return Sandeepan Nath. ====================================================================================== The problem The results returned by the above query are correct (AND logic working as per expectation), but the time taken by the query on heavily loaded databases is like 25 seconds as against normal query timings of the order of 0.005 - 0.0002 seconds, which makes it totally unusable. It is possible that some of the delay is being caused because all the possible fields have not yet been indexed, but I would appreciate a better query as a solution, optimized as much as possible, displaying the same results ========================================================================================== How tags work in this system? When a tutor registers, tags are entered and tag relations are created with respect to tutor's details like name, surname etc. When a Tutors create packs, again tags are entered and tag relations are created with respect to pack's details like pack name, description etc. tag relations for tutors stored in tutors_tag_relations and those for packs stored in learning_packs_tag_relations. All individual tags are stored in tags table. ==================================================================== The tables Most of the following tables contain many other fields which I have omitted here. CREATE TABLE IF NOT EXISTS users ( id_user int(10) unsigned NOT NULL AUTO_INCREMENT, name varchar(100) NOT NULL DEFAULT '', surname varchar(155) NOT NULL DEFAULT '', PRIMARY KEY (id_user) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=636 ; CREATE TABLE IF NOT EXISTS tutor_details ( id_tutor int(10) NOT NULL AUTO_INCREMENT, id_user int(10) NOT NULL DEFAULT '0', PRIMARY KEY (id_tutor), KEY Users_FKIndex1 (id_user) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=51 ; CREATE TABLE IF NOT EXISTS orders ( id_order int(10) unsigned NOT NULL AUTO_INCREMENT, PRIMARY KEY (id_order), KEY Orders_FKIndex1 (id_user), ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=275 ; ALTER TABLE orders ADD CONSTRAINT Orders_ibfk_1 FOREIGN KEY (id_user) REFERENCES users (id_user) ON DELETE NO ACTION ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS order_details ( id_od int(10) unsigned NOT NULL AUTO_INCREMENT, id_order int(10) unsigned NOT NULL DEFAULT '0', id_author int(10) NOT NULL DEFAULT '0', PRIMARY KEY (id_od), KEY Order_Details_FKIndex1 (id_order) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=284 ; ALTER TABLE order_details ADD CONSTRAINT Order_Details_ibfk_1 FOREIGN KEY (id_order) REFERENCES orders (id_order) ON DELETE NO ACTION ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS learning_packs ( id_lp int(10) unsigned NOT NULL AUTO_INCREMENT, id_author int(10) unsigned NOT NULL DEFAULT '0', PRIMARY KEY (id_lp), KEY Learning_Packs_FKIndex2 (id_author), KEY id_lp (id_lp) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=23 ; CREATE TABLE IF NOT EXISTS tags ( id_tag int(10) unsigned NOT NULL AUTO_INCREMENT, tag varchar(255) DEFAULT NULL, PRIMARY KEY (id_tag), UNIQUE KEY tag (tag), KEY id_tag (id_tag), KEY tag_2 (tag), KEY tag_3 (tag) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3419 ; CREATE TABLE IF NOT EXISTS tutors_tag_relations ( id_tag int(10) unsigned NOT NULL DEFAULT '0', id_tutor int(10) DEFAULT NULL, KEY Tutors_Tag_Relations (id_tag), KEY id_tutor (id_tutor), KEY id_tag (id_tag) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; ALTER TABLE tutors_tag_relations ADD CONSTRAINT Tutors_Tag_Relations_ibfk_1 FOREIGN KEY (id_tag) REFERENCES tags (id_tag) ON DELETE NO ACTION ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS learning_packs_tag_relations ( id_tag int(10) unsigned NOT NULL DEFAULT '0', id_tutor int(10) DEFAULT NULL, id_lp int(10) unsigned DEFAULT NULL, KEY Learning_Packs_Tag_Relations_FKIndex1 (id_tag), KEY id_lp (id_lp), KEY id_tag (id_tag) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; ALTER TABLE learning_packs_tag_relations ADD CONSTRAINT Learning_Packs_Tag_Relations_ibfk_1 FOREIGN KEY (id_tag) REFERENCES tags (id_tag) ON DELETE NO ACTION ON UPDATE NO ACTION; =================================================================================== Following is the exact query (this includes classes also - tutors can create classes and search terms are matched with classes created by tutors):- select count(distinct(od.id_od)) as tutor_popularity, CASE WHEN (IF((wc.id_wc 0), ( wc.wc_api_status = 1 AND wc.wc_type = 0 AND wc.class_date '2010-06-01 22:00:56' AND wccp.status = 1 AND (wccp.country_code='IE' or wccp.country_code IN ('INT'))), 0)) THEN 1 ELSE 0 END as 'classes_published', CASE WHEN (IF((lp.id_lp 0), (lp.id_status = 1 AND lp.published = 1 AND lpcp.status = 1 AND (lpcp.country_code='IE' or lpcp.country_code IN ('INT'))),0)) THEN 1 ELSE 0 END as 'packs_published', td . * , u . * from Tutor_Details AS td JOIN Users as u on u.id_user = td.id_user LEFT JOIN Learning_Packs_Tag_Relations AS lptagrels ON td.id_tutor = lptagrels.id_tutor LEFT JOIN Learning_Packs AS lp ON lptagrels.id_lp = lp.id_lp LEFT JOIN Learning_Packs_Categories AS lpc ON lpc.id_lp_cat = lp.id_lp_cat LEFT JOIN Learning_Packs_Categories AS lpcp ON lpcp.id_lp_cat = lpc.id_parent LEFT JOIN Learning_Pack_Content as lpct on (lp.id_lp = lpct.id_lp) LEFT JOIN Webclasses_Tag_Relations AS wtagrels ON td.id_tutor = wtagrels.id_tutor LEFT JOIN WebClasses AS wc ON wtagrels.id_wc = wc.id_wc LEFT JOIN Learning_Packs_Categories AS wcc ON wcc.id_lp_cat = wc.id_wp_cat LEFT JOIN Learning_Packs_Categories AS wccp ON wccp.id_lp_cat = wcc.id_parent LEFT JOIN Order_Details as od on td.id_tutor = od.id_author LEFT JOIN Orders as o on od.id_order = o.id_order LEFT JOIN Tutors_Tag_Relations as ttagrels ON td.id_tutor = ttagrels.id_tutor JOIN Tags as t on (t.id_tag = ttagrels.id_tag) OR (t.id_tag = lptagrels.id_tag) OR (t.id_tag = wtagrels.id_tag) where (u.country='IE' or u.country IN ('INT')) AND CASE WHEN ((t.id_tag = lptagrels.id_tag) AND (lp.id_lp 0)) THEN lp.id_status = 1 AND lp.published = 1 AND lpcp.status = 1 AND (lpcp.country_code='IE' or lpcp.country_code IN ('INT')) ELSE 1 END AND CASE WHEN ((t.id_tag = wtagrels.id_tag) AND (wc.id_wc 0)) THEN wc.wc_api_status = 1 AND wc.wc_type = 0 AND wc.class_date '2010-06-01 22:00:56' AND wccp.status = 1 AND (wccp.country_code='IE' or wccp.country_code IN ('INT')) ELSE 1 END AND CASE WHEN (od.id_od0) THEN od.id_author = td.id_tutor and o.order_status = 'paid' and CASE WHEN (od.id_wc 0) THEN od.can_attend_class=1 ELSE 1 END ELSE 1 END AND 1 group by td.id_tutor order by tutor_popularity desc, u.surname asc, u.name asc limit 0,20 Please note - The provided database structure does not show all the fields and tables as in this query

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A way of doing real-world test-driven development (and some thoughts about it)

- by Thomas Weller

Lately, I exchanged some arguments with Derick Bailey about some details of the red-green-refactor cycle of the Test-driven development process. In short, the issue revolved around the fact that it’s not enough to have a test red or green, but it’s also important to have it red or green for the right reasons. While for me, it’s sufficient to initially have a NotImplementedException in place, Derick argues that this is not totally correct (see these two posts: Red/Green/Refactor, For The Right Reasons and Red For The Right Reason: Fail By Assertion, Not By Anything Else). And he’s right. But on the other hand, I had no idea how his insights could have any practical consequence for my own individual interpretation of the red-green-refactor cycle (which is not really red-green-refactor, at least not in its pure sense, see the rest of this article). This made me think deeply for some days now. In the end I found out that the ‘right reason’ changes in my understanding depending on what development phase I’m in. To make this clear (at least I hope it becomes clear…) I started to describe my way of working in some detail, and then something strange happened: The scope of the article slightly shifted from focusing ‘only’ on the ‘right reason’ issue to something more general, which you might describe as something like 'Doing real-world TDD in .NET , with massive use of third-party add-ins’. This is because I feel that there is a more general statement about Test-driven development to make: It’s high time to speak about the ‘How’ of TDD, not always only the ‘Why’. Much has been said about this, and me myself also contributed to that (see here: TDD is not about testing, it's about how we develop software). But always justifying what you do is very unsatisfying in the long run, it is inherently defensive, and it costs time and effort that could be used for better and more important things. And frankly: I’m somewhat sick and tired of repeating time and again that the test-driven way of software development is highly preferable for many reasons - I don’t want to spent my time exclusively on stating the obvious… So, again, let’s say it clearly: TDD is programming, and programming is TDD. Other ways of programming (code-first, sometimes called cowboy-coding) are exceptional and need justification. – I know that there are many people out there who will disagree with this radical statement, and I also know that it’s not a description of the real world but more of a mission statement or something. But nevertheless I’m absolutely sure that in some years this statement will be nothing but a platitude. Side note: Some parts of this post read as if I were paid by Jetbrains (the manufacturer of the ReSharper add-in – R#), but I swear I’m not. Rather I think that Visual Studio is just not production-complete without it, and I wouldn’t even consider to do professional work without having this add-in installed... The three parts of a software component Before I go into some details, I first should describe my understanding of what belongs to a software component (assembly, type, or method) during the production process (i.e. the coding phase). Roughly, I come up with the three parts shown below: First, we need to have some initial sort of requirement. This can be a multi-page formal document, a vague idea in some programmer’s brain of what might be needed, or anything in between. In either way, there has to be some sort of requirement, be it explicit or not. – At the C# micro-level, the best way that I found to formulate that is to define interfaces for just about everything, even for internal classes, and to provide them with exhaustive xml comments. The next step then is to re-formulate these requirements in an executable form. This is specific to the respective programming language. - For C#/.NET, the Gallio framework (which includes MbUnit) in conjunction with the ReSharper add-in for Visual Studio is my toolset of choice. The third part then finally is the production code itself. It’s development is entirely driven by the requirements and their executable formulation. This is the delivery, the two other parts are ‘only’ there to make its production possible, to give it a decent quality and reliability, and to significantly reduce related costs down the maintenance timeline. So while the first two parts are not really relevant for the customer, they are very important for the developer. The customer (or in Scrum terms: the Product Owner) is not interested at all in how the product is developed, he is only interested in the fact that it is developed as cost-effective as possible, and that it meets his functional and non-functional requirements. The rest is solely a matter of the developer’s craftsmanship, and this is what I want to talk about during the remainder of this article… An example To demonstrate my way of doing real-world TDD, I decided to show the development of a (very) simple Calculator component. The example is deliberately trivial and silly, as examples always are. I am totally aware of the fact that real life is never that simple, but I only want to show some development principles here… The requirement As already said above, I start with writing down some words on the initial requirement, and I normally use interfaces for that, even for internal classes - the typical question “intf or not” doesn’t even come to mind. I need them for my usual workflow and using them automatically produces high componentized and testable code anyway. To think about their usage in every single situation would slow down the production process unnecessarily. So this is what I begin with: namespace Calculator { /// <summary> /// Defines a very simple calculator component for demo purposes. /// </summary> public interface ICalculator { /// <summary> /// Gets the result of the last successful operation. /// </summary> /// <value>The last result.</value> /// <remarks> /// Will be <see langword="null" /> before the first successful operation. /// </remarks> double? LastResult { get; } } // interface ICalculator } // namespace Calculator So, I’m not beginning with a test, but with a sort of code declaration - and still I insist on being 100% test-driven. There are three important things here: Starting this way gives me a method signature, which allows to use IntelliSense and AutoCompletion and thus eliminates the danger of typos - one of the most regular, annoying, time-consuming, and therefore expensive sources of error in the development process. In my understanding, the interface definition as a whole is more of a readable requirement document and technical documentation than anything else. So this is at least as much about documentation than about coding. The documentation must completely describe the behavior of the documented element. I normally use an IoC container or some sort of self-written provider-like model in my architecture. In either case, I need my components defined via service interfaces anyway. - I will use the LinFu IoC framework here, for no other reason as that is is very simple to use. The ‘Red’ (pt. 1) First I create a folder for the project’s third-party libraries and put the LinFu.Core dll there. Then I set up a test project (via a Gallio project template), and add references to the Calculator project and the LinFu dll. Finally I’m ready to write the first test, which will look like the following: namespace Calculator.Test { [TestFixture] public class CalculatorTest { private readonly ServiceContainer container = new ServiceContainer(); [Test] public void CalculatorLastResultIsInitiallyNull() { ICalculator calculator = container.GetService<ICalculator>(); Assert.IsNull(calculator.LastResult); } } // class CalculatorTest } // namespace Calculator.Test This is basically the executable formulation of what the interface definition states (part of). Side note: There’s one principle of TDD that is just plain wrong in my eyes: I’m talking about the Red is 'does not compile' thing. How could a compiler error ever be interpreted as a valid test outcome? I never understood that, it just makes no sense to me. (Or, in Derick’s terms: this reason is as wrong as a reason ever could be…) A compiler error tells me: Your code is incorrect, but nothing more. Instead, the ‘Red’ part of the red-green-refactor cycle has a clearly defined meaning to me: It means that the test works as intended and fails only if its assumptions are not met for some reason. Back to our Calculator. When I execute the above test with R#, the Gallio plugin will give me this output: So this tells me that the test is red for the wrong reason: There’s no implementation that the IoC-container could load, of course. So let’s fix that. With R#, this is very easy: First, create an ICalculator - derived type: Next, implement the interface members: And finally, move the new class to its own file: So far my ‘work’ was six mouse clicks long, the only thing that’s left to do manually here, is to add the Ioc-specific wiring-declaration and also to make the respective class non-public, which I regularly do to force my components to communicate exclusively via interfaces: This is what my Calculator class looks like as of now: using System; using LinFu.IoC.Configuration; namespace Calculator { [Implements(typeof(ICalculator))] internal class Calculator : ICalculator { public double? LastResult { get { throw new NotImplementedException(); } } } } Back to the test fixture, we have to put our IoC container to work: [TestFixture] public class CalculatorTest { #region Fields private readonly ServiceContainer container = new ServiceContainer(); #endregion // Fields #region Setup/TearDown [FixtureSetUp] public void FixtureSetUp() { container.LoadFrom(AppDomain.CurrentDomain.BaseDirectory, "Calculator.dll"); } ... Because I have a R# live template defined for the setup/teardown method skeleton as well, the only manual coding here again is the IoC-specific stuff: two lines, not more… The ‘Red’ (pt. 2) Now, the execution of the above test gives the following result: This time, the test outcome tells me that the method under test is called. And this is the point, where Derick and I seem to have somewhat different views on the subject: Of course, the test still is worthless regarding the red/green outcome (or: it’s still red for the wrong reasons, in that it gives a false negative). But as far as I am concerned, I’m not really interested in the test outcome at this point of the red-green-refactor cycle. Rather, I only want to assert that my test actually calls the right method. If that’s the case, I will happily go on to the ‘Green’ part… The ‘Green’ Making the test green is quite trivial. Just make LastResult an automatic property: [Implements(typeof(ICalculator))] internal class Calculator : ICalculator { public double? LastResult { get; private set; } } One more round… Now on to something slightly more demanding (cough…). Let’s state that our Calculator exposes an Add() method: ... /// <summary> /// Adds the specified operands. /// </summary> /// <param name="operand1">The operand1.</param> /// <param name="operand2">The operand2.</param> /// <returns>The result of the additon.</returns> /// <exception cref="ArgumentException"> /// Argument <paramref name="operand1"/> is < 0.<br/> /// -- or --<br/> /// Argument <paramref name="operand2"/> is < 0. /// </exception> double Add(double operand1, double operand2); } // interface ICalculator A remark: I sometimes hear the complaint that xml comment stuff like the above is hard to read. That’s certainly true, but irrelevant to me, because I read xml code comments with the CR_Documentor tool window. And using that, it looks like this: Apart from that, I’m heavily using xml code comments (see e.g. here for a detailed guide) because there is the possibility of automating help generation with nightly CI builds (using MS Sandcastle and the Sandcastle Help File Builder), and then publishing the results to some intranet location. This way, a team always has first class, up-to-date technical documentation at hand about the current codebase. (And, also very important for speeding up things and avoiding typos: You have IntelliSense/AutoCompletion and R# support, and the comments are subject to compiler checking…). Back to our Calculator again: Two more R# – clicks implement the Add() skeleton: ... public double Add(double operand1, double operand2) { throw new NotImplementedException(); } } // class Calculator As we have stated in the interface definition (which actually serves as our requirement document!), the operands are not allowed to be negative. So let’s start implementing that. Here’s the test: [Test] [Row(-0.5, 2)] public void AddThrowsOnNegativeOperands(double operand1, double operand2) { ICalculator calculator = container.GetService<ICalculator>(); Assert.Throws<ArgumentException>(() => calculator.Add(operand1, operand2)); } As you can see, I’m using a data-driven unit test method here, mainly for these two reasons: Because I know that I will have to do the same test for the second operand in a few seconds, I save myself from implementing another test method for this purpose. Rather, I only will have to add another Row attribute to the existing one. From the test report below, you can see that the argument values are explicitly printed out. This can be a valuable documentation feature even when everything is green: One can quickly review what values were tested exactly - the complete Gallio HTML-report (as it will be produced by the Continuous Integration runs) shows these values in a quite clear format (see below for an example). Back to our Calculator development again, this is what the test result tells us at the moment: So we’re red again, because there is not yet an implementation… Next we go on and implement the necessary parameter verification to become green again, and then we do the same thing for the second operand. To make a long story short, here’s the test and the method implementation at the end of the second cycle: // in CalculatorTest: [Test] [Row(-0.5, 2)] [Row(295, -123)] public void AddThrowsOnNegativeOperands(double operand1, double operand2) { ICalculator calculator = container.GetService<ICalculator>(); Assert.Throws<ArgumentException>(() => calculator.Add(operand1, operand2)); } // in Calculator: public double Add(double operand1, double operand2) { if (operand1 < 0.0) { throw new ArgumentException("Value must not be negative.", "operand1"); } if (operand2 < 0.0) { throw new ArgumentException("Value must not be negative.", "operand2"); } throw new NotImplementedException(); } So far, we have sheltered our method from unwanted input, and now we can safely operate on the parameters without further caring about their validity (this is my interpretation of the Fail Fast principle, which is regarded here in more detail). Now we can think about the method’s successful outcomes. First let’s write another test for that: [Test] [Row(1, 1, 2)] public void TestAdd(double operand1, double operand2, double expectedResult) { ICalculator calculator = container.GetService<ICalculator>(); double result = calculator.Add(operand1, operand2); Assert.AreEqual(expectedResult, result); } Again, I’m regularly using row based test methods for these kinds of unit tests. The above shown pattern proved to be extremely helpful for my development work, I call it the Defined-Input/Expected-Output test idiom: You define your input arguments together with the expected method result. There are two major benefits from that way of testing: In the course of refining a method, it’s very likely to come up with additional test cases. In our case, we might add tests for some edge cases like ‘one of the operands is zero’ or ‘the sum of the two operands causes an overflow’, or maybe there’s an external test protocol that has to be fulfilled (e.g. an ISO norm for medical software), and this results in the need of testing against additional values. In all these scenarios we only have to add another Row attribute to the test. Remember that the argument values are written to the test report, so as a side-effect this produces valuable documentation. (This can become especially important if the fulfillment of some sort of external requirements has to be proven). So your test method might look something like that in the end: [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 2)] [Row(0, 999999999, 999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, double.MaxValue)] [Row(4, double.MaxValue - 2.5, double.MaxValue)] public void TestAdd(double operand1, double operand2, double expectedResult) { ICalculator calculator = container.GetService<ICalculator>(); double result = calculator.Add(operand1, operand2); Assert.AreEqual(expectedResult, result); } And this will produce the following HTML report (with Gallio): Not bad for the amount of work we invested in it, huh? - There might be scenarios where reports like that can be useful for demonstration purposes during a Scrum sprint review… The last requirement to fulfill is that the LastResult property is expected to store the result of the last operation. I don’t show this here, it’s trivial enough and brings nothing new… And finally: Refactor (for the right reasons) To demonstrate my way of going through the refactoring portion of the red-green-refactor cycle, I added another method to our Calculator component, namely Subtract(). Here’s the code (tests and production): // CalculatorTest.cs: [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 0)] [Row(0, 999999999, -999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, -double.MaxValue)] [Row(4, double.MaxValue - 2.5, -double.MaxValue)] public void TestSubtract(double operand1, double operand2, double expectedResult) { ICalculator calculator = container.GetService<ICalculator>(); double result = calculator.Subtract(operand1, operand2); Assert.AreEqual(expectedResult, result); } [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 0)] [Row(0, 999999999, -999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, -double.MaxValue)] [Row(4, double.MaxValue - 2.5, -double.MaxValue)] public void TestSubtractGivesExpectedLastResult(double operand1, double operand2, double expectedResult) { ICalculator calculator = container.GetService<ICalculator>(); calculator.Subtract(operand1, operand2); Assert.AreEqual(expectedResult, calculator.LastResult); } ... // ICalculator.cs: /// <summary> /// Subtracts the specified operands. /// </summary> /// <param name="operand1">The operand1.</param> /// <param name="operand2">The operand2.</param> /// <returns>The result of the subtraction.</returns> /// <exception cref="ArgumentException"> /// Argument <paramref name="operand1"/> is < 0.<br/> /// -- or --<br/> /// Argument <paramref name="operand2"/> is < 0. /// </exception> double Subtract(double operand1, double operand2); ... // Calculator.cs: public double Subtract(double operand1, double operand2) { if (operand1 < 0.0) { throw new ArgumentException("Value must not be negative.", "operand1"); } if (operand2 < 0.0) { throw new ArgumentException("Value must not be negative.", "operand2"); } return (this.LastResult = operand1 - operand2).Value; } Obviously, the argument validation stuff that was produced during the red-green part of our cycle duplicates the code from the previous Add() method. So, to avoid code duplication and minimize the number of code lines of the production code, we do an Extract Method refactoring. One more time, this is only a matter of a few mouse clicks (and giving the new method a name) with R#: Having done that, our production code finally looks like that: using System; using LinFu.IoC.Configuration; namespace Calculator { [Implements(typeof(ICalculator))] internal class Calculator : ICalculator { #region ICalculator public double? LastResult { get; private set; } public double Add(double operand1, double operand2) { ThrowIfOneOperandIsInvalid(operand1, operand2); return (this.LastResult = operand1 + operand2).Value; } public double Subtract(double operand1, double operand2) { ThrowIfOneOperandIsInvalid(operand1, operand2); return (this.LastResult = operand1 - operand2).Value; } #endregion // ICalculator #region Implementation (Helper) private static void ThrowIfOneOperandIsInvalid(double operand1, double operand2) { if (operand1 < 0.0) { throw new ArgumentException("Value must not be negative.", "operand1"); } if (operand2 < 0.0) { throw new ArgumentException("Value must not be negative.", "operand2"); } } #endregion // Implementation (Helper) } // class Calculator } // namespace Calculator But is the above worth the effort at all? It’s obviously trivial and not very impressive. All our tests were green (for the right reasons), and refactoring the code did not change anything. It’s not immediately clear how this refactoring work adds value to the project. Derick puts it like this: STOP! Hold on a second… before you go any further and before you even think about refactoring what you just wrote to make your test pass, you need to understand something: if your done with your requirements after making the test green, you are not required to refactor the code. I know… I’m speaking heresy, here. Toss me to the wolves, I’ve gone over to the dark side! Seriously, though… if your test is passing for the right reasons, and you do not need to write any test or any more code for you class at this point, what value does refactoring add? Derick immediately answers his own question: So why should you follow the refactor portion of red/green/refactor? When you have added code that makes the system less readable, less understandable, less expressive of the domain or concern’s intentions, less architecturally sound, less DRY, etc, then you should refactor it. I couldn’t state it more precise. From my personal perspective, I’d add the following: You have to keep in mind that real-world software systems are usually quite large and there are dozens or even hundreds of occasions where micro-refactorings like the above can be applied. It’s the sum of them all that counts. And to have a good overall quality of the system (e.g. in terms of the Code Duplication Percentage metric) you have to be pedantic on the individual, seemingly trivial cases. My job regularly requires the reading and understanding of ‘foreign’ code. So code quality/readability really makes a HUGE difference for me – sometimes it can be even the difference between project success and failure… Conclusions The above described development process emerged over the years, and there were mainly two things that guided its evolution (you might call it eternal principles, personal beliefs, or anything in between): Test-driven development is the normal, natural way of writing software, code-first is exceptional. So ‘doing TDD or not’ is not a question. And good, stable code can only reliably be produced by doing TDD (yes, I know: many will strongly disagree here again, but I’ve never seen high-quality code – and high-quality code is code that stood the test of time and causes low maintenance costs – that was produced code-first…) It’s the production code that pays our bills in the end. (Though I have seen customers these days who demand an acceptance test battery as part of the final delivery. Things seem to go into the right direction…). The test code serves ‘only’ to make the production code work. But it’s the number of delivered features which solely counts at the end of the day - no matter how much test code you wrote or how good it is. With these two things in mind, I tried to optimize my coding process for coding speed – or, in business terms: productivity - without sacrificing the principles of TDD (more than I’d do either way…). As a result, I consider a ratio of about 3-5/1 for test code vs. production code as normal and desirable. In other words: roughly 60-80% of my code is test code (This might sound heavy, but that is mainly due to the fact that software development standards only begin to evolve. The entire software development profession is very young, historically seen; only at the very beginning, and there are no viable standards yet. If you think about software development as a kind of casting process, where the test code is the mold and the resulting production code is the final product, then the above ratio sounds no longer extraordinary…) Although the above might look like very much unnecessary work at first sight, it’s not. With the aid of the mentioned add-ins, doing all the above is a matter of minutes, sometimes seconds (while writing this post took hours and days…). The most important thing is to have the right tools at hand. Slow developer machines or the lack of a tool or something like that - for ‘saving’ a few 100 bucks - is just not acceptable and a very bad decision in business terms (though I quite some times have seen and heard that…). Production of high-quality products needs the usage of high-quality tools. This is a platitude that every craftsman knows… The here described round-trip will take me about five to ten minutes in my real-world development practice. I guess it’s about 30% more time compared to developing the ‘traditional’ (code-first) way. But the so manufactured ‘product’ is of much higher quality and massively reduces maintenance costs, which is by far the single biggest cost factor, as I showed in this previous post: It's the maintenance, stupid! (or: Something is rotten in developerland.). In the end, this is a highly cost-effective way of software development… But on the other hand, there clearly is a trade-off here: coding speed vs. code quality/later maintenance costs. The here described development method might be a perfect fit for the overwhelming majority of software projects, but there certainly are some scenarios where it’s not - e.g. if time-to-market is crucial for a software project. So this is a business decision in the end. It’s just that you have to know what you’re doing and what consequences this might have… Some last words First, I’d like to thank Derick Bailey again. His two aforementioned posts (which I strongly recommend for reading) inspired me to think deeply about my own personal way of doing TDD and to clarify my thoughts about it. I wouldn’t have done that without this inspiration. I really enjoy that kind of discussions… I agree with him in all respects. But I don’t know (yet?) how to bring his insights into the described production process without slowing things down. The above described method proved to be very “good enough” in my practical experience. But of course, I’m open to suggestions here… My rationale for now is: If the test is initially red during the red-green-refactor cycle, the ‘right reason’ is: it actually calls the right method, but this method is not yet operational. Later on, when the cycle is finished and the tests become part of the regular, automated Continuous Integration process, ‘red’ certainly must occur for the ‘right reason’: in this phase, ‘red’ MUST mean nothing but an unfulfilled assertion - Fail By Assertion, Not By Anything Else!

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Zen and the Art of File and Folder Organization

- by Mark Virtue

Is your desk a paragon of neatness, or does it look like a paper-bomb has gone off? If you’ve been putting off getting organized because the task is too huge or daunting, or you don’t know where to start, we’ve got 40 tips to get you on the path to zen mastery of your filing system. For all those readers who would like to get their files and folders organized, or, if they’re already organized, better organized—we have compiled a complete guide to getting organized and staying organized, a comprehensive article that will hopefully cover every possible tip you could want. Signs that Your Computer is Poorly Organized If your computer is a mess, you’re probably already aware of it. But just in case you’re not, here are some tell-tale signs: Your Desktop has over 40 icons on it “My Documents” contains over 300 files and 60 folders, including MP3s and digital photos You use the Windows’ built-in search facility whenever you need to find a file You can’t find programs in the out-of-control list of programs in your Start Menu You save all your Word documents in one folder, all your spreadsheets in a second folder, etc Any given file that you’re looking for may be in any one of four different sets of folders But before we start, here are some quick notes: We’re going to assume you know what files and folders are, and how to create, save, rename, copy and delete them The organization principles described in this article apply equally to all computer systems. However, the screenshots here will reflect how things look on Windows (usually Windows 7). We will also mention some useful features of Windows that can help you get organized. Everyone has their own favorite methodology of organizing and filing, and it’s all too easy to get into “My Way is Better than Your Way” arguments. The reality is that there is no perfect way of getting things organized. When I wrote this article, I tried to keep a generalist and objective viewpoint. I consider myself to be unusually well organized (to the point of obsession, truth be told), and I’ve had 25 years experience in collecting and organizing files on computers. So I’ve got a lot to say on the subject. But the tips I have described here are only one way of doing it. Hopefully some of these tips will work for you too, but please don’t read this as any sort of “right” way to do it. At the end of the article we’ll be asking you, the reader, for your own organization tips. Why Bother Organizing At All? For some, the answer to this question is self-evident. And yet, in this era of powerful desktop search software (the search capabilities built into the Windows Vista and Windows 7 Start Menus, and third-party programs like Google Desktop Search), the question does need to be asked, and answered. I have a friend who puts every file he ever creates, receives or downloads into his My Documents folder and doesn’t bother filing them into subfolders at all. He relies on the search functionality built into his Windows operating system to help him find whatever he’s looking for. And he always finds it. He’s a Search Samurai. For him, filing is a waste of valuable time that could be spent enjoying life! It’s tempting to follow suit. On the face of it, why would anyone bother to take the time to organize their hard disk when such excellent search software is available? Well, if all you ever want to do with the files you own is to locate and open them individually (for listening, editing, etc), then there’s no reason to ever bother doing one scrap of organization. But consider these common tasks that are not achievable with desktop search software: Find files manually. Often it’s not convenient, speedy or even possible to utilize your desktop search software to find what you want. It doesn’t work 100% of the time, or you may not even have it installed. Sometimes its just plain faster to go straight to the file you want, if you know it’s in a particular sub-folder, rather than trawling through hundreds of search results. Find groups of similar files (e.g. all your “work” files, all the photos of your Europe holiday in 2008, all your music videos, all the MP3s from Dark Side of the Moon, all your letters you wrote to your wife, all your tax returns). Clever naming of the files will only get you so far. Sometimes it’s the date the file was created that’s important, other times it’s the file format, and other times it’s the purpose of the file. How do you name a collection of files so that they’re easy to isolate based on any of the above criteria? Short answer, you can’t. Move files to a new computer. It’s time to upgrade your computer. How do you quickly grab all the files that are important to you? Or you decide to have two computers now – one for home and one for work. How do you quickly isolate only the work-related files to move them to the work computer? Synchronize files to other computers. If you have more than one computer, and you need to mirror some of your files onto the other computer (e.g. your music collection), then you need a way to quickly determine which files are to be synced and which are not. Surely you don’t want to synchronize everything? Choose which files to back up. If your backup regime calls for multiple backups, or requires speedy backups, then you’ll need to be able to specify which files are to be backed up, and which are not. This is not possible if they’re all in the same folder. Finally, if you’re simply someone who takes pleasure in being organized, tidy and ordered (me! me!), then you don’t even need a reason. Being disorganized is simply unthinkable. Tips on Getting Organized Here we present our 40 best tips on how to get organized. Or, if you’re already organized, to get better organized. Tip #1. Choose Your Organization System Carefully The reason that most people are not organized is that it takes time. And the first thing that takes time is deciding upon a system of organization. This is always a matter of personal preference, and is not something that a geek on a website can tell you. You should always choose your own system, based on how your own brain is organized (which makes the assumption that your brain is, in fact, organized). We can’t instruct you, but we can make suggestions: You may want to start off with a system based on the users of the computer. i.e. “My Files”, “My Wife’s Files”, My Son’s Files”, etc. Inside “My Files”, you might then break it down into “Personal” and “Business”. You may then realize that there are overlaps. For example, everyone may want to share access to the music library, or the photos from the school play. So you may create another folder called “Family”, for the “common” files. You may decide that the highest-level breakdown of your files is based on the “source” of each file. In other words, who created the files. You could have “Files created by ME (business or personal)”, “Files created by people I know (family, friends, etc)”, and finally “Files created by the rest of the world (MP3 music files, downloaded or ripped movies or TV shows, software installation files, gorgeous desktop wallpaper images you’ve collected, etc).” This system happens to be the one I use myself. See below: Mark is for files created by meVC is for files created by my company (Virtual Creations)Others is for files created by my friends and familyData is the rest of the worldAlso, Settings is where I store the configuration files and other program data files for my installed software (more on this in tip #34, below). Each folder will present its own particular set of requirements for further sub-organization. For example, you may decide to organize your music collection into sub-folders based on the artist’s name, while your digital photos might get organized based on the date they were taken. It can be different for every sub-folder! Another strategy would be based on “currentness”. Files you have yet to open and look at live in one folder. Ones that have been looked at but not yet filed live in another place. Current, active projects live in yet another place. All other files (your “archive”, if you like) would live in a fourth folder. (And of course, within that last folder you’d need to create a further sub-system based on one of the previous bullet points). Put some thought into this – changing it when it proves incomplete can be a big hassle! Before you go to the trouble of implementing any system you come up with, examine a wide cross-section of the files you own and see if they will all be able to find a nice logical place to sit within your system. Tip #2. When You Decide on Your System, Stick to It! There’s nothing more pointless than going to all the trouble of creating a system and filing all your files, and then whenever you create, receive or download a new file, you simply dump it onto your Desktop. You need to be disciplined – forever! Every new file you get, spend those extra few seconds to file it where it belongs! Otherwise, in just a month or two, you’ll be worse off than before – half your files will be organized and half will be disorganized – and you won’t know which is which! Tip #3. Choose the Root Folder of Your Structure Carefully Every data file (document, photo, music file, etc) that you create, own or is important to you, no matter where it came from, should be found within one single folder, and that one single folder should be located at the root of your C: drive (as a sub-folder of C:\). In other words, do not base your folder structure in standard folders like “My Documents”. If you do, then you’re leaving it up to the operating system engineers to decide what folder structure is best for you. And every operating system has a different system! In Windows 7 your files are found in C:\Users\YourName, whilst on Windows XP it was C:\Documents and Settings\YourName\My Documents. In UNIX systems it’s often /home/YourName. These standard default folders tend to fill up with junk files and folders that are not at all important to you. “My Documents” is the worst offender. Every second piece of software you install, it seems, likes to create its own folder in the “My Documents” folder. These folders usually don’t fit within your organizational structure, so don’t use them! In fact, don’t even use the “My Documents” folder at all. Allow it to fill up with junk, and then simply ignore it. It sounds heretical, but: Don’t ever visit your “My Documents” folder! Remove your icons/links to “My Documents” and replace them with links to the folders you created and you care about! Create your own file system from scratch! Probably the best place to put it would be on your D: drive – if you have one. This way, all your files live on one drive, while all the operating system and software component files live on the C: drive – simply and elegantly separated. The benefits of that are profound. Not only are there obvious organizational benefits (see tip #10, below), but when it comes to migrate your data to a new computer, you can (sometimes) simply unplug your D: drive and plug it in as the D: drive of your new computer (this implies that the D: drive is actually a separate physical disk, and not a partition on the same disk as C:). You also get a slight speed improvement (again, only if your C: and D: drives are on separate physical disks). Warning: From tip #12, below, you will see that it’s actually a good idea to have exactly the same file system structure – including the drive it’s filed on – on all of the computers you own. So if you decide to use the D: drive as the storage system for your own files, make sure you are able to use the D: drive on all the computers you own. If you can’t ensure that, then you can still use a clever geeky trick to store your files on the D: drive, but still access them all via the C: drive (see tip #17, below). If you only have one hard disk (C:), then create a dedicated folder that will contain all your files – something like C:\Files. The name of the folder is not important, but make it a single, brief word. There are several reasons for this: When creating a backup regime, it’s easy to decide what files should be backed up – they’re all in the one folder! If you ever decide to trade in your computer for a new one, you know exactly which files to migrate You will always know where to begin a search for any file If you synchronize files with other computers, it makes your synchronization routines very simple. It also causes all your shortcuts to continue to work on the other machines (more about this in tip #24, below). Once you’ve decided where your files should go, then put all your files in there – Everything! Completely disregard the standard, default folders that are created for you by the operating system (“My Music”, “My Pictures”, etc). In fact, you can actually relocate many of those folders into your own structure (more about that below, in tip #6). The more completely you get all your data files (documents, photos, music, etc) and all your configuration settings into that one folder, then the easier it will be to perform all of the above tasks. Once this has been done, and all your files live in one folder, all the other folders in C:\ can be thought of as “operating system” folders, and therefore of little day-to-day interest for us. Here’s a screenshot of a nicely organized C: drive, where all user files are located within the \Files folder: Tip #4. Use Sub-Folders This would be our simplest and most obvious tip. It almost goes without saying. Any organizational system you decide upon (see tip #1) will require that you create sub-folders for your files. Get used to creating folders on a regular basis. Tip #5. Don’t be Shy About Depth Create as many levels of sub-folders as you need. Don’t be scared to do so. Every time you notice an opportunity to group a set of related files into a sub-folder, do so. Examples might include: All the MP3s from one music CD, all the photos from one holiday, or all the documents from one client. It’s perfectly okay to put files into a folder called C:\Files\Me\From Others\Services\WestCo Bank\Statements\2009. That’s only seven levels deep. Ten levels is not uncommon. Of course, it’s possible to take this too far. If you notice yourself creating a sub-folder to hold only one file, then you’ve probably become a little over-zealous. On the other hand, if you simply create a structure with only two levels (for example C:\Files\Work) then you really haven’t achieved any level of organization at all (unless you own only six files!). Your “Work” folder will have become a dumping ground, just like your Desktop was, with most likely hundreds of files in it. Tip #6. Move the Standard User Folders into Your Own Folder Structure Most operating systems, including Windows, create a set of standard folders for each of its users. These folders then become the default location for files such as documents, music files, digital photos and downloaded Internet files. In Windows 7, the full list is shown below: Some of these folders you may never use nor care about (for example, the Favorites folder, if you’re not using Internet Explorer as your browser). Those ones you can leave where they are. But you may be using some of the other folders to store files that are important to you. Even if you’re not using them, Windows will still often treat them as the default storage location for many types of files. When you go to save a standard file type, it can become annoying to be automatically prompted to save it in a folder that’s not part of your own file structure. But there’s a simple solution: Move the folders you care about into your own folder structure! If you do, then the next time you go to save a file of the corresponding type, Windows will prompt you to save it in the new, moved location. Moving the folders is easy. Simply drag-and-drop them to the new location. Here’s a screenshot of the default My Music folder being moved to my custom personal folder (Mark): Tip #7. Name Files and Folders Intelligently This is another one that almost goes without saying, but we’ll say it anyway: Do not allow files to be created that have meaningless names like Document1.doc, or folders called New Folder (2). Take that extra 20 seconds and come up with a meaningful name for the file/folder – one that accurately divulges its contents without repeating the entire contents in the name. Tip #8. Watch Out for Long Filenames Another way to tell if you have not yet created enough depth to your folder hierarchy is that your files often require really long names. If you need to call a file Johnson Sales Figures March 2009.xls (which might happen to live in the same folder as Abercrombie Budget Report 2008.xls), then you might want to create some sub-folders so that the first file could be simply called March.xls, and living in the Clients\Johnson\Sales Figures\2009 folder. A well-placed file needs only a brief filename! Tip #9. Use Shortcuts! Everywhere! This is probably the single most useful and important tip we can offer. A shortcut allows a file to be in two places at once. Why would you want that? Well, the file and folder structure of every popular operating system on the market today is hierarchical. This means that all objects (files and folders) always live within exactly one parent folder. It’s a bit like a tree. A tree has branches (folders) and leaves (files). Each leaf, and each branch, is supported by exactly one parent branch, all the way back to the root of the tree (which, incidentally, is exactly why C:\ is called the “root folder” of the C: drive). That hard disks are structured this way may seem obvious and even necessary, but it’s only one way of organizing data. There are others: Relational databases, for example, organize structured data entirely differently. The main limitation of hierarchical filing structures is that a file can only ever be in one branch of the tree – in only one folder – at a time. Why is this a problem? Well, there are two main reasons why this limitation is a problem for computer users: The “correct” place for a file, according to our organizational rationale, is very often a very inconvenient place for that file to be located. Just because it’s correctly filed doesn’t mean it’s easy to get to. Your file may be “correctly” buried six levels deep in your sub-folder structure, but you may need regular and speedy access to this file every day. You could always move it to a more convenient location, but that would mean that you would need to re-file back to its “correct” location it every time you’d finished working on it. Most unsatisfactory. A file may simply “belong” in two or more different locations within your file structure. For example, say you’re an accountant and you have just completed the 2009 tax return for John Smith. It might make sense to you to call this file 2009 Tax Return.doc and file it under Clients\John Smith. But it may also be important to you to have the 2009 tax returns from all your clients together in the one place. So you might also want to call the file John Smith.doc and file it under Tax Returns\2009. The problem is, in a purely hierarchical filing system, you can’t put it in both places. Grrrrr! Fortunately, Windows (and most other operating systems) offers a way for you to do exactly that: It’s called a “shortcut” (also known as an “alias” on Macs and a “symbolic link” on UNIX systems). Shortcuts allow a file to exist in one place, and an icon that represents the file to be created and put anywhere else you please. In fact, you can create a dozen such icons and scatter them all over your hard disk. Double-clicking on one of these icons/shortcuts opens up the original file, just as if you had double-clicked on the original file itself. Consider the following two icons: The one on the left is the actual Word document, while the one on the right is a shortcut that represents the Word document. Double-clicking on either icon will open the same file. There are two main visual differences between the icons: The shortcut will have a small arrow in the lower-left-hand corner (on Windows, anyway) The shortcut is allowed to have a name that does not include the file extension (the “.docx” part, in this case) You can delete the shortcut at any time without losing any actual data. The original is still intact. All you lose is the ability to get to that data from wherever the shortcut was. So why are shortcuts so great? Because they allow us to easily overcome the main limitation of hierarchical file systems, and put a file in two (or more) places at the same time. You will always have files that don’t play nice with your organizational rationale, and can’t be filed in only one place. They demand to exist in two places. Shortcuts allow this! Furthermore, they allow you to collect your most often-opened files and folders together in one spot for convenient access. The cool part is that the original files stay where they are, safe forever in their perfectly organized location. So your collection of most often-opened files can – and should – become a collection of shortcuts! If you’re still not convinced of the utility of shortcuts, consider the following well-known areas of a typical Windows computer: The Start Menu (and all the programs that live within it) The Quick Launch bar (or the Superbar in Windows 7) The “Favorite folders” area in the top-left corner of the Windows Explorer window (in Windows Vista or Windows 7) Your Internet Explorer Favorites or Firefox Bookmarks Each item in each of these areas is a shortcut! Each of those areas exist for one purpose only: For convenience – to provide you with a collection of the files and folders you access most often. It should be easy to see by now that shortcuts are designed for one single purpose: To make accessing your files more convenient. Each time you double-click on a shortcut, you are saved the hassle of locating the file (or folder, or program, or drive, or control panel icon) that it represents. Shortcuts allow us to invent a golden rule of file and folder organization: “Only ever have one copy of a file – never have two copies of the same file. Use a shortcut instead” (this rule doesn’t apply to copies created for backup purposes, of course!) There are also lesser rules, like “don’t move a file into your work area – create a shortcut there instead”, and “any time you find yourself frustrated with how long it takes to locate a file, create a shortcut to it and place that shortcut in a convenient location.” So how to we create these massively useful shortcuts? There are two main ways: “Copy” the original file or folder (click on it and type Ctrl-C, or right-click on it and select Copy): Then right-click in an empty area of the destination folder (the place where you want the shortcut to go) and select Paste shortcut: Right-drag (drag with the right mouse button) the file from the source folder to the destination folder. When you let go of the mouse button at the destination folder, a menu pops up: Select Create shortcuts here. Note that when shortcuts are created, they are often named something like Shortcut to Budget Detail.doc (windows XP) or Budget Detail – Shortcut.doc (Windows 7). If you don’t like those extra words, you can easily rename the shortcuts after they’re created, or you can configure Windows to never insert the extra words in the first place (see our article on how to do this). And of course, you can create shortcuts to folders too, not just to files! Bottom line: Whenever you have a file that you’d like to access from somewhere else (whether it’s convenience you’re after, or because the file simply belongs in two places), create a shortcut to the original file in the new location. Tip #10. Separate Application Files from Data Files Any digital organization guru will drum this rule into you. Application files are the components of the software you’ve installed (e.g. Microsoft Word, Adobe Photoshop or Internet Explorer). Data files are the files that you’ve created for yourself using that software (e.g. Word Documents, digital photos, emails or playlists). Software gets installed, uninstalled and upgraded all the time. Hopefully you always have the original installation media (or downloaded set-up file) kept somewhere safe, and can thus reinstall your software at any time. This means that the software component files are of little importance. Whereas the files you have created with that software is, by definition, important. It’s a good rule to always separate unimportant files from important files. So when your software prompts you to save a file you’ve just created, take a moment and check out where it’s suggesting that you save the file. If it’s suggesting that you save the file into the same folder as the software itself, then definitely don’t follow that suggestion. File it in your own folder! In fact, see if you can find the program’s configuration option that determines where files are saved by default (if it has one), and change it. Tip #11. Organize Files Based on Purpose, Not on File Type If you have, for example a folder called Work\Clients\Johnson, and within that folder you have two sub-folders, Word Documents and Spreadsheets (in other words, you’re separating “.doc” files from “.xls” files), then chances are that you’re not optimally organized. It makes little sense to organize your files based on the program that created them. Instead, create your sub-folders based on the purpose of the file. For example, it would make more sense to create sub-folders called Correspondence and Financials. It may well be that all the files in a given sub-folder are of the same file-type, but this should be more of a coincidence and less of a design feature of your organization system. Tip #12. Maintain the Same Folder Structure on All Your Computers In other words, whatever organizational system you create, apply it to every computer that you can. There are several benefits to this: There’s less to remember. No matter where you are, you always know where to look for your files If you copy or synchronize files from one computer to another, then setting up the synchronization job becomes very simple Shortcuts can be copied or moved from one computer to another with ease (assuming the original files are also copied/moved). There’s no need to find the target of the shortcut all over again on the second computer Ditto for linked files (e.g Word documents that link to data in a separate Excel file), playlists, and any files that reference the exact file locations of other files. This applies even to the drive that your files are stored on. If your files are stored on C: on one computer, make sure they’re stored on C: on all your computers. Otherwise all your shortcuts, playlists and linked files will stop working! Tip #13. Create an “Inbox” Folder Create yourself a folder where you store all files that you’re currently working on, or that you haven’t gotten around to filing yet. You can think of this folder as your “to-do” list. You can call it “Inbox” (making it the same metaphor as your email system), or “Work”, or “To-Do”, or “Scratch”, or whatever name makes sense to you. It doesn’t matter what you call it – just make sure you have one! Once you have finished working on a file, you then move it from the “Inbox” to its correct location within your organizational structure. You may want to use your Desktop as this “Inbox” folder. Rightly or wrongly, most people do. It’s not a bad place to put such files, but be careful: If you do decide that your Desktop represents your “to-do” list, then make sure that no other files find their way there. In other words, make sure that your “Inbox”, wherever it is, Desktop or otherwise, is kept free of junk – stray files that don’t belong there. So where should you put this folder, which, almost by definition, lives outside the structure of the rest of your filing system? Well, first and foremost, it has to be somewhere handy. This will be one of your most-visited folders, so convenience is key. Putting it on the Desktop is a great option – especially if you don’t have any other folders on your Desktop: the folder then becomes supremely easy to find in Windows Explorer: You would then create shortcuts to this folder in convenient spots all over your computer (“Favorite Links”, “Quick Launch”, etc). Tip #14. Ensure You have Only One “Inbox” Folder Once you’ve created your “Inbox” folder, don’t use any other folder location as your “to-do list”. Throw every incoming or created file into the Inbox folder as you create/receive it. This keeps the rest of your computer pristine and free of randomly created or downloaded junk. The last thing you want to be doing is checking multiple folders to see all your current tasks and projects. Gather them all together into one folder. Here are some tips to help ensure you only have one Inbox: Set the default “save” location of all your programs to this folder. Set the default “download” location for your browser to this folder. If this folder is not your desktop (recommended) then also see if you can make a point of not putting “to-do” files on your desktop. This keeps your desktop uncluttered and Zen-like: (the Inbox folder is in the bottom-right corner) Tip #15. Be Vigilant about Clearing Your “Inbox” Folder This is one of the keys to staying organized. If you let your “Inbox” overflow (i.e. allow there to be more than, say, 30 files or folders in there), then you’re probably going to start feeling like you’re overwhelmed: You’re not keeping up with your to-do list. Once your Inbox gets beyond a certain point (around 30 files, studies have shown), then you’ll simply start to avoid it. You may continue to put files in there, but you’ll be scared to look at it, fearing the “out of control” feeling that all overworked, chaotic or just plain disorganized people regularly feel. So, here’s what you can do: Visit your Inbox/to-do folder regularly (at least five times per day). Scan the folder regularly for files that you have completed working on and are ready for filing. File them immediately. Make it a source of pride to keep the number of files in this folder as small as possible. If you value peace of mind, then make the emptiness of this folder one of your highest (computer) priorities If you know that a particular file has been in the folder for more than, say, six weeks, then admit that you’re not actually going to get around to processing it, and move it to its final resting place. Tip #16. File Everything Immediately, and Use Shortcuts for Your Active Projects As soon as you create, receive or download a new file, store it away in its “correct” folder immediately. Then, whenever you need to work on it (possibly straight away), create a shortcut to it in your “Inbox” (“to-do”) folder or your desktop. That way, all your files are always in their “correct” locations, yet you still have immediate, convenient access to your current, active files. When you finish working on a file, simply delete the shortcut. Ideally, your “Inbox” folder – and your Desktop – should contain no actual files or folders. They should simply contain shortcuts. Tip #17. Use Directory Symbolic Links (or Junctions) to Maintain One Unified Folder Structure Using this tip, we can get around a potential hiccup that we can run into when creating our organizational structure – the issue of having more than one drive on our computer (C:, D:, etc). We might have files we need to store on the D: drive for space reasons, and yet want to base our organized folder structure on the C: drive (or vice-versa). Your chosen organizational structure may dictate that all your files must be accessed from the C: drive (for example, the root folder of all your files may be something like C:\Files). And yet you may still have a D: drive and wish to take advantage of the hundreds of spare Gigabytes that it offers. Did you know that it’s actually possible to store your files on the D: drive and yet access them as if they were on the C: drive? And no, we’re not talking about shortcuts here (although the concept is very similar). By using the shell command mklink, you can essentially take a folder that lives on one drive and create an alias for it on a different drive (you can do lots more than that with mklink – for a full rundown on this programs capabilities, see our dedicated article). These aliases are called directory symbolic links (and used to be known as junctions). You can think of them as “virtual” folders. They function exactly like regular folders, except they’re physically located somewhere else. For example, you may decide that your entire D: drive contains your complete organizational file structure, but that you need to reference all those files as if they were on the C: drive, under C:\Files. If that was the case you could create C:\Files as a directory symbolic link – a link to D:, as follows: mklink /d c:\files d:\ Or it may be that the only files you wish to store on the D: drive are your movie collection. You could locate all your movie files in the root of your D: drive, and then link it to C:\Files\Media\Movies, as follows: mklink /d c:\files\media\movies d:\ (Needless to say, you must run these commands from a command prompt – click the Start button, type cmd and press Enter) Tip #18. Customize Your Folder Icons This is not strictly speaking an organizational tip, but having unique icons for each folder does allow you to more quickly visually identify which folder is which, and thus saves you time when you’re finding files. An example is below (from my folder that contains all files downloaded from the Internet): To learn how to change your folder icons, please refer to our dedicated article on the subject. Tip #19. Tidy Your Start Menu The Windows Start Menu is usually one of the messiest parts of any Windows computer. Every program you install seems to adopt a completely different approach to placing icons in this menu. Some simply put a single program icon. Others create a folder based on the name of the software. And others create a folder based on the name of the software manufacturer. It’s chaos, and can make it hard to find the software you want to run. Thankfully we can avoid this chaos with useful operating system features like Quick Launch, the Superbar or pinned start menu items. Even so, it would make a lot of sense to get into the guts of the Start Menu itself and give it a good once-over. All you really need to decide is how you’re going to organize your applications. A structure based on the purpose of the application is an obvious candidate. Below is an example of one such structure: In this structure, Utilities means software whose job it is to keep the computer itself running smoothly (configuration tools, backup software, Zip programs, etc). Applications refers to any productivity software that doesn’t fit under the headings Multimedia, Graphics, Internet, etc. In case you’re not aware, every icon in your Start Menu is a shortcut and can be manipulated like any other shortcut (copied, moved, deleted, etc). With the Windows Start Menu (all version of Windows), Microsoft has decided that there be two parallel folder structures to store your Start Menu shortcuts. One for you (the logged-in user of the computer) and one for all users of the computer. Having two parallel structures can often be redundant: If you are the only user of the computer, then having two parallel structures is totally redundant. Even if you have several users that regularly log into the computer, most of your installed software will need to be made available to all users, and should thus be moved out of the “just you” version of the Start Menu and into the “all users” area. To take control of your Start Menu, so you can start organizing it, you’ll need to know how to access the actual folders and shortcut files that make up the Start Menu (both versions of it). To find these folders and files, click the Start button and then right-click on the All Programs text (Windows XP users should right-click on the Start button itself): The Open option refers to the “just you” version of the Start Menu, while the Open All Users option refers to the “all users” version. Click on the one you want to organize. A Windows Explorer window then opens with your chosen version of the Start Menu selected. From there it’s easy. Double-click on the Programs folder and you’ll see all your folders and shortcuts. Now you can delete/rename/move until it’s just the way you want it. Note: When you’re reorganizing your Start Menu, you may want to have two Explorer windows open at the same time – one showing the “just you” version and one showing the “all users” version. You can drag-and-drop between the windows. Tip #20. Keep Your Start Menu Tidy Once you have a perfectly organized Start Menu, try to be a little vigilant about keeping it that way. Every time you install a new piece of software, the icons that get created will almost certainly violate your organizational structure. So to keep your Start Menu pristine and organized, make sure you do the following whenever you install a new piece of software: Check whether the software was installed into the “just you” area of the Start Menu, or the “all users” area, and then move it to the correct area. Remove all the unnecessary icons (like the “Read me” icon, the “Help” icon (you can always open the help from within the software itself when it’s running), the “Uninstall” icon, the link(s)to the manufacturer’s website, etc) Rename the main icon(s) of the software to something brief that makes sense to you. For example, you might like to rename Microsoft Office Word 2010 to simply Word Move the icon(s) into the correct folder based on your Start Menu organizational structure And don’t forget: when you uninstall a piece of software, the software’s uninstall routine is no longer going to be able to remove the software’s icon from the Start Menu (because you moved and/or renamed it), so you’ll need to remove that icon manually. Tip #21. Tidy C:\ The root of your C: drive (C:\) is a common dumping ground for files and folders – both by the users of your computer and by the software that you install on your computer. It can become a mess. There’s almost no software these days that requires itself to be installed in C:\. 99% of the time it can and should be installed into C:\Program Files. And as for your own files, well, it’s clear that they can (and almost always should) be stored somewhere else. In an ideal world, your C:\ folder should look like this (on Windows 7): Note that there are some system files and folders in C:\ that are usually and deliberately “hidden” (such as the Windows virtual memory file pagefile.sys, the boot loader file bootmgr, and the System Volume Information folder). Hiding these files and folders is a good idea, as they need to stay where they are and are almost never needed to be opened or even seen by you, the user. Hiding them prevents you from accidentally messing with them, and enhances your sense of order and well-being when you look at your C: drive folder. Tip #22. Tidy Your Desktop The Desktop is probably the most abused part of a Windows computer (from an organization point of view). It usually serves as a dumping ground for all incoming files, as well as holding icons to oft-used applications, plus some regularly opened files and folders. It often ends up becoming an uncontrolled mess. See if you can avoid this. Here’s why… Application icons (Word, Internet Explorer, etc) are often found on the Desktop, but it’s unlikely that this is the optimum place for them. The “Quick Launch” bar (or the Superbar in Windows 7) is always visible and so represents a perfect location to put your icons. You’ll only be able to see the icons on your Desktop when all your programs are minimized. It might be time to get your application icons off your desktop… You may have decided that the Inbox/To-do folder on your computer (see tip #13, above) should be your Desktop. If so, then enough said. Simply be vigilant about clearing it and preventing it from being polluted by junk files (see tip #15, above). On the other hand, if your Desktop is not acting as your “Inbox” folder, then there’s no reason for it to have any data files or folders on it at all, except perhaps a couple of shortcuts to often-opened files and folders (either ongoing or current projects). Everything else should be moved to your “Inbox” folder. In an ideal world, it might look like this: Tip #23. Move Permanent Items on Your Desktop Away from the Top-Left Corner When files/folders are dragged onto your desktop in a Windows Explorer window, or when shortcuts are created on your Desktop from Internet Explorer, those icons are always placed in the top-left corner – or as close as they can get. If you have other files, folders or shortcuts that you keep on the Desktop permanently, then it’s a good idea to separate these permanent icons from the transient ones, so that you can quickly identify which ones the transients are. An easy way to do this is to move all your permanent icons to the right-hand side of your Desktop. That should keep them separated from incoming items. Tip #24. Synchronize If you have more than one computer, you’ll almost certainly want to share files between them. If the computers are permanently attached to the same local network, then there’s no need to store multiple copies of any one file or folder – shortcuts will suffice. However, if the computers are not always on the same network, then you will at some point need to copy files between them. For files that need to permanently live on both computers, the ideal way to do this is to synchronize the files, as opposed to simply copying them. We only have room here to write a brief summary of synchronization, not a full article. In short, there are several different types of synchronization: Where the contents of one folder are accessible anywhere, such as with Dropbox Where the contents of any number of folders are accessible anywhere, such as with Windows Live Mesh Where any files or folders from anywhere on your computer are synchronized with exactly one other computer, such as with the Windows “Briefcase”, Microsoft SyncToy, or (much more powerful, yet still free) SyncBack from 2BrightSparks. This only works when both computers are on the same local network, at least temporarily. A great advantage of synchronization solutions is that once you’ve got it configured the way you want it, then the sync process happens automatically, every time. Click a button (or schedule it to happen automatically) and all your files are automagically put where they’re supposed to be. If you maintain the same file and folder structure on both computers, then you can also sync files depend upon the correct location of other files, like shortcuts, playlists and office documents that link to other office documents, and the synchronized files still work on the other computer! Tip #25. Hide Files You Never Need to See If you have your files well organized, you will often be able to tell if a file is out of place just by glancing at the contents of a folder (for example, it should be pretty obvious if you look in a folder that contains all the MP3s from one music CD and see a Word document in there). This is a good thing – it allows you to determine if there are files out of place with a quick glance. Yet sometimes there are files in a folder that seem out of place but actually need to be there, such as the “folder art” JPEGs in music folders, and various files in the root of the C: drive. If such files never need to be opened by you, then a good idea is to simply hide them. Then, the next time you glance at the folder, you won’t have to remember whether that file was supposed to be there or not, because you won’t see it at all! To hide a file, simply right-click on it and choose Properties: Then simply tick the Hidden tick-box: Tip #26. Keep Every Setup File These days most software is downloaded from the Internet. Whenever you download a piece of software, keep it. You’ll never know when you need to reinstall the software. Further, keep with it an Internet shortcut that links back to the website where you originally downloaded it, in case you ever need to check for updates. See tip #33 below for a full description of the excellence of organizing your setup files. Tip #27. Try to Minimize the Number of Folders that Contain Both Files and Sub-folders Some of the folders in your organizational structure will contain only files. Others will contain only sub-folders. And you will also have some folders that contain both files and sub-folders. You will notice slight improvements in how long it takes you to locate a file if you try to avoid this third type of folder. It’s not always possible, of course – you’ll always have some of these folders, but see if you can avoid it. One way of doing this is to take all the leftover files that didn’t end up getting stored in a sub-folder and create a special “Miscellaneous” or “Other” folder for them. Tip #28. Starting a Filename with an Underscore Brings it to the Top of a List Further to the previous tip, if you name that “Miscellaneous” or “Other” folder in such a way that its name begins with an underscore “_”, then it will appear at the top of the list of files/folders. The screenshot below is an example of this. Each folder in the list contains a set of digital photos. The folder at the top of the list, _Misc, contains random photos that didn’t deserve their own dedicated folder: Tip #29. Clean Up those CD-ROMs and (shudder!) Floppy Disks Have you got a pile of CD-ROMs stacked on a shelf of your office? Old photos, or files you archived off onto CD-ROM (or even worse, floppy disks!) because you didn’t have enough disk space at the time? In the meantime have you upgraded your computer and now have 500 Gigabytes of space you don’t know what to do with? If so, isn’t it time you tidied up that stack of disks and filed them into your gorgeous new folder structure? So what are you waiting for? Bite the bullet, copy them all back onto your computer, file them in their appropriate folders, and then back the whole lot up onto a shiny new 1000Gig external hard drive! Useful Folders to Create This next section suggests some useful folders that you might want to create within your folder structure. I’ve personally found them to be indispensable. The first three are all about convenience – handy folders to create and then put somewhere that you can always access instantly. For each one, it’s not so important where the actual folder is located, but it’s very important where you put the shortcut(s) to the folder. You might want to locate the shortcuts: On your Desktop In your “Quick Launch” area (or pinned to your Windows 7 Superbar) In your Windows Explorer “Favorite Links” area Tip #30. Create an “Inbox” (“To-Do”) Folder This has already been mentioned in depth (see tip #13), but we wanted to reiterate its importance here. This folder contains all the recently created, received or downloaded files that you have not yet had a chance to file away properly, and it also may contain files that you have yet to process. In effect, it becomes a sort of “to-do list”. It doesn’t have to be called “Inbox” – you can call it whatever you want. Tip #31. Create a Folder where Your Current Projects are Collected Rather than going hunting for them all the time, or dumping them all on your desktop, create a special folder where you put links (or work folders) for each of the projects you’re currently working on. You can locate this folder in your “Inbox” folder, on your desktop, or anywhere at all – just so long as there’s a way of getting to it quickly, such as putting a link to it in Windows Explorer’s “Favorite Links” area: Tip #32. Create a Folder for Files and Folders that You Regularly Open You will always have a few files that you open regularly, whether it be a spreadsheet of your current accounts, or a favorite playlist. These are not necessarily “current projects”, rather they’re simply files that you always find yourself opening. Typically such files would be located on your desktop (or even better, shortcuts to those files). Why not collect all such shortcuts together and put them in their own special folder? As with the “Current Projects” folder (above), you would want to locate that folder somewhere convenient. Below is an example of a folder called “Quick links”, with about seven files (shortcuts) in it, that is accessible through the Windows Quick Launch bar: See tip #37 below for a full explanation of the power of the Quick Launch bar. Tip #33. Create a “Set-ups” Folder A typical computer has dozens of applications installed on it. For each piece of software, there are often many different pieces of information you need to keep track of, including: The original installation setup file(s). This can be anything from a simple 100Kb setup.exe file you downloaded from a website, all the way up to a 4Gig ISO file that you copied from a DVD-ROM that you purchased. The home page of the software manufacturer (in case you need to look up something on their support pages, their forum or their online help) The page containing the download link for your actual file (in case you need to re-download it, or download an upgraded version) The serial number Your proof-of-purchase documentation Any other template files, plug-ins, themes, etc that also need to get installed For each piece of software, it’s a great idea to gather all of these files together and put them in a single folder. The folder can be the name of the software (plus possibly a very brief description of what it’s for – in case you can’t remember what the software does based in its name). Then you would gather all of these folders together into one place, and call it something like “Software” or “Setups”. If you have enough of these folders (I have several hundred, being a geek, collected over 20 years), then you may want to further categorize them. My own categorization structure is based on “platform” (operating system): The last seven folders each represents one platform/operating system, while _Operating Systems contains set-up files for installing the operating systems themselves. _Hardware contains ROMs for hardware I own, such as routers. Within the Windows folder (above), you can see the beginnings of the vast library of software I’ve compiled over the years: An example of a typical application folder looks like this: Tip #34. Have a “Settings” Folder We all know that our documents are important. So are our photos and music files. We save all of these files into folders, and then locate them afterwards and double-click on them to open them. But there are many files that are important to us that can’t be saved into folders, and then searched for and double-clicked later on. These files certainly contain important information that we need, but are often created internally by an application, and saved wherever that application feels is appropriate. A good example of this is the “PST” file that Outlook creates for us and uses to store all our emails, contacts, appointments and so forth. Another example would be the collection of Bookmarks that Firefox stores on your behalf. And yet another example would be the customized settings and configuration files of our all our software. Granted, most Windows programs store their configuration in the Registry, but there are still many programs that use configuration files to store their settings. Imagine if you lost all of the above files! And yet, when people are backing up their computers, they typically only back up the files they know about – those that are stored in the “My Documents” folder, etc. If they had a hard disk failure or their computer was lost or stolen, their backup files would not include some of the most vital files they owned. Also, when migrating to a new computer, it’s vital to ensure that these files make the journey. It can be a very useful idea to create yourself a folder to store all your “settings” – files that are important to you but which you never actually search for by name and double-click on to open them. Otherwise, next time you go to set up a new computer just the way you want it, you’ll need to spend hours recreating the configuration of your previous computer! So how to we get our important files into this folder? Well, we have a few options: Some programs (such as Outlook and its PST files) allow you to place these files wherever you want. If you delve into the program’s options, you will find a setting somewhere that controls the location of the important settings files (or “personal storage” – PST – when it comes to Outlook) Some programs do not allow you to change such locations in any easy way, but if you get into the Registry, you can sometimes find a registry key that refers to the location of the file(s). Simply move the file into your Settings folder and adjust the registry key to refer to the new location. Some programs stubbornly refuse to allow their settings files to be placed anywhere other then where they stipulate. When faced with programs like these, you have three choices: (1) You can ignore those files, (2) You can copy the files into your Settings folder (let’s face it – settings don’t change very often), or (3) you can use synchronization software, such as the Windows Briefcase, to make synchronized copies of all your files in your Settings folder. All you then have to do is to remember to run your sync software periodically (perhaps just before you run your backup software!). There are some other things you may decide to locate inside this new “Settings” folder: Exports of registry keys (from the many applications that store their configurations in the Registry). This is useful for backup purposes or for migrating to a new computer Notes you’ve made about all the specific customizations you have made to a particular piece of software (so that you’ll know how to do it all again on your next computer) Shortcuts to webpages that detail how to tweak certain aspects of your operating system or applications so they are just the way you like them (such as how to remove the words “Shortcut to” from the beginning of newly created shortcuts). In other words, you’d want to create shortcuts to half the pages on the How-To Geek website! Here’s an example of a “Settings” folder: Windows Features that Help with Organization This section details some of the features of Microsoft Windows that are a boon to anyone hoping to stay optimally organized. Tip #35. Use the “Favorite Links” Area to Access Oft-Used Folders Once you’ve created your great new filing system, work out which folders you access most regularly, or which serve as great starting points for locating the rest of the files in your folder structure, and then put links to those folders in your “Favorite Links” area of the left-hand side of the Windows Explorer window (simply called “Favorites” in Windows 7): Some ideas for folders you might want to add there include: Your “Inbox” folder (or whatever you’ve called it) – most important! The base of your filing structure (e.g. C:\Files) A folder containing shortcuts to often-accessed folders on other computers around the network (shown above as Network Folders) A folder containing shortcuts to your current projects (unless that folder is in your “Inbox” folder) Getting folders into this area is very simple – just locate the folder you’re interested in and drag it there! Tip #36. Customize the Places Bar in the File/Open and File/Save Boxes Consider the screenshot below: The highlighted icons (collectively known as the “Places Bar”) can be customized to refer to any folder location you want, allowing instant access to any part of your organizational structure. Note: These File/Open and File/Save boxes have been superseded by new versions that use the Windows Vista/Windows 7 “Favorite Links”, but the older versions (shown above) are still used by a surprisingly large number of applications. The easiest way to customize these icons is to use the Group Policy Editor, but not everyone has access to this program. If you do, open it up and navigate to: User Configuration > Administrative Templates > Windows Components > Windows Explorer > Common Open File Dialog If you don’t have access to the Group Policy Editor, then you’ll need to get into the Registry. Navigate to: HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Policies \ comdlg32 \ Placesbar It should then be easy to make the desired changes. Log off and log on again to allow the changes to take effect. Tip #37. Use the Quick Launch Bar as a Application and File Launcher That Quick Launch bar (to the right of the Start button) is a lot more useful than people give it credit for. Most people simply have half a dozen icons in it, and use it to start just those programs. But it can actually be used to instantly access just about anything in your filing system: For complete instructions on how to set this up, visit our dedicated article on this topic. Tip #38. Put a Shortcut to Windows Explorer into Your Quick Launch Bar This is only necessary in Windows Vista and Windows XP. The Microsoft boffins finally got wise and added it to the Windows 7 Superbar by default. Windows Explorer – the program used for managing your files and folders – is one of the most useful programs in Windows. Anyone who considers themselves serious about being organized needs instant access to this program at any time. A great place to create a shortcut to this program is in the Windows XP and Windows Vista “Quick Launch” bar: To get it there, locate it in your Start Menu (usually under “Accessories”) and then right-drag it down into your Quick Launch bar (and create a copy). Tip #39. Customize the Starting Folder for Your Windows 7 Explorer Superbar Icon If you’re on Windows 7, your Superbar will include a Windows Explorer icon. Clicking on the icon will launch Windows Explorer (of course), and will start you off in your “Libraries” folder. Libraries may be fine as a starting point, but if you have created yourself an “Inbox” folder, then it would probably make more sense to start off in this folder every time you launch Windows Explorer. To change this default/starting folder location, then first right-click the Explorer icon in the Superbar, and then right-click Properties:Then, in Target field of the Windows Explorer Properties box that appears, type %windir%\explorer.exe followed by the path of the folder you wish to start in. For example: %windir%\explorer.exe C:\Files If that folder happened to be on the Desktop (and called, say, “Inbox”), then you would use the following cleverness: %windir%\explorer.exe shell:desktop\Inbox Then click OK and test it out. Tip #40. Ummmmm…. No, that’s it. I can’t think of another one. That’s all of the tips I can come up with. I only created this one because 40 is such a nice round number… Case Study – An Organized PC To finish off the article, I have included a few screenshots of my (main) computer (running Vista). The aim here is twofold: To give you a sense of what it looks like when the above, sometimes abstract, tips are applied to a real-life computer, and To offer some ideas about folders and structure that you may want to steal to use on your own PC. Let’s start with the C: drive itself. Very minimal. All my files are contained within C:\Files. I’ll confine the rest of the case study to this folder: That folder contains the following: Mark: My personal files VC: My business (Virtual Creations, Australia) Others contains files created by friends and family Data contains files from the rest of the world (can be thought of as “public” files, usually downloaded from the Net) Settings is described above in tip #34 The Data folder contains the following sub-folders: Audio: Radio plays, audio books, podcasts, etc Development: Programmer and developer resources, sample source code, etc (see below) Humour: Jokes, funnies (those emails that we all receive) Movies: Downloaded and ripped movies (all legal, of course!), their scripts, DVD covers, etc. Music: (see below) Setups: Installation files for software (explained in full in tip #33) System: (see below) TV: Downloaded TV shows Writings: Books, instruction manuals, etc (see below) The Music folder contains the following sub-folders: Album covers: JPEG scans Guitar tabs: Text files of guitar sheet music Lists: e.g. “Top 1000 songs of all time” Lyrics: Text files MIDI: Electronic music files MP3 (representing 99% of the Music folder): MP3s, either ripped from CDs or downloaded, sorted by artist/album name Music Video: Video clips Sheet Music: usually PDFs The Data\Writings folder contains the following sub-folders: (all pretty self-explanatory) The Data\Development folder contains the following sub-folders: Again, all pretty self-explanatory (if you’re a geek) The Data\System folder contains the following sub-folders: These are usually themes, plug-ins and other downloadable program-specific resources. The Mark folder contains the following sub-folders: From Others: Usually letters that other people (friends, family, etc) have written to me For Others: Letters and other things I have created for other people Green Book: None of your business Playlists: M3U files that I have compiled of my favorite songs (plus one M3U playlist file for every album I own) Writing: Fiction, philosophy and other musings of mine Mark Docs: Shortcut to C:\Users\Mark Settings: Shortcut to C:\Files\Settings\Mark The Others folder contains the following sub-folders: The VC (Virtual Creations, my business – I develop websites) folder contains the following sub-folders: And again, all of those are pretty self-explanatory. Conclusion These tips have saved my sanity and helped keep me a productive geek, but what about you? What tips and tricks do you have to keep your files organized? Please share them with us in the comments. Come on, don’t be shy… Similar Articles Productive Geek Tips Fix For When Windows Explorer in Vista Stops Showing File NamesWhy Did Windows Vista’s Music Folder Icon Turn Yellow?Print or Create a Text File List of the Contents in a Directory the Easy WayCustomize the Windows 7 or Vista Send To MenuAdd Copy To / Move To on Windows 7 or Vista Right-Click Menu TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows Track Daily Goals With 42Goals Video Toolbox is a Superb Online Video Editor Fun with 47 charts and graphs Tomorrow is Mother’s Day Check the Average Speed of YouTube Videos You’ve Watched OutlookStatView Scans and Displays General Usage Statistics

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How John Got 15x Improvement Without Really Trying

- by rchrd

The following article was published on a Sun Microsystems website a number of years ago by John Feo. It is still useful and worth preserving. So I'm republishing it here. How I Got 15x Improvement Without Really Trying John Feo, Sun Microsystems Taking ten "personal" program codes used in scientific and engineering research, the author was able to get from 2 to 15 times performance improvement easily by applying some simple general optimization techniques. Introduction Scientific research based on computer simulation depends on the simulation for advancement. The research can advance only as fast as the computational codes can execute. The codes' efficiency determines both the rate and quality of results. In the same amount of time, a faster program can generate more results and can carry out a more detailed simulation of physical phenomena than a slower program. Highly optimized programs help science advance quickly and insure that monies supporting scientific research are used as effectively as possible. Scientific computer codes divide into three broad categories: ISV, community, and personal. ISV codes are large, mature production codes developed and sold commercially. The codes improve slowly over time both in methods and capabilities, and they are well tuned for most vendor platforms. Since the codes are mature and complex, there are few opportunities to improve their performance solely through code optimization. Improvements of 10% to 15% are typical. Examples of ISV codes are DYNA3D, Gaussian, and Nastran. Community codes are non-commercial production codes used by a particular research field. Generally, they are developed and distributed by a single academic or research institution with assistance from the community. Most users just run the codes, but some develop new methods and extensions that feed back into the general release. The codes are available on most vendor platforms. Since these codes are younger than ISV codes, there are more opportunities to optimize the source code. Improvements of 50% are not unusual. Examples of community codes are AMBER, CHARM, BLAST, and FASTA. Personal codes are those written by single users or small research groups for their own use. These codes are not distributed, but may be passed from professor-to-student or student-to-student over several years. They form the primordial ocean of applications from which community and ISV codes emerge. Government research grants pay for the development of most personal codes. This paper reports on the nature and performance of this class of codes. Over the last year, I have looked at over two dozen personal codes from more than a dozen research institutions. The codes cover a variety of scientific fields, including astronomy, atmospheric sciences, bioinformatics, biology, chemistry, geology, and physics. The sources range from a few hundred lines to more than ten thousand lines, and are written in Fortran, Fortran 90, C, and C++. For the most part, the codes are modular, documented, and written in a clear, straightforward manner. They do not use complex language features, advanced data structures, programming tricks, or libraries. I had little trouble understanding what the codes did or how data structures were used. Most came with a makefile. Surprisingly, only one of the applications is parallel. All developers have access to parallel machines, so availability is not an issue. Several tried to parallelize their applications, but stopped after encountering difficulties. Lack of education and a perception that parallelism is difficult prevented most from trying. I parallelized several of the codes using OpenMP, and did not judge any of the codes as difficult to parallelize. Even more surprising than the lack of parallelism is the inefficiency of the codes. I was able to get large improvements in performance in a matter of a few days applying simple optimization techniques. Table 1 lists ten representative codes [names and affiliation are omitted to preserve anonymity]. Improvements on one processor range from 2x to 15.5x with a simple average of 4.75x. I did not use sophisticated performance tools or drill deep into the program's execution character as one would do when tuning ISV or community codes. Using only a profiler and source line timers, I identified inefficient sections of code and improved their performance by inspection. The changes were at a high level. I am sure there is another factor of 2 or 3 in each code, and more if the codes are parallelized. The study’s results show that personal scientific codes are running many times slower than they should and that the problem is pervasive. Computational scientists are not sloppy programmers; however, few are trained in the art of computer programming or code optimization. I found that most have a working knowledge of some programming language and standard software engineering practices; but they do not know, or think about, how to make their programs run faster. They simply do not know the standard techniques used to make codes run faster. In fact, they do not even perceive that such techniques exist. The case studies described in this paper show that applying simple, well known techniques can significantly increase the performance of personal codes. It is important that the scientific community and the Government agencies that support scientific research find ways to better educate academic scientific programmers. The inefficiency of their codes is so bad that it is retarding both the quality and progress of scientific research. # cacheperformance redundantoperations loopstructures performanceimprovement 1 x x 15.5 2 x 2.8 3 x x 2.5 4 x 2.1 5 x x 2.0 6 x 5.0 7 x 5.8 8 x 6.3 9 2.2 10 x x 3.3 Table 1 — Area of improvement and performance gains of 10 codes The remainder of the paper is organized as follows: sections 2, 3, and 4 discuss the three most common sources of inefficiencies in the codes studied. These are cache performance, redundant operations, and loop structures. Each section includes several examples. The last section summaries the work and suggests a possible solution to the issues raised. Optimizing cache performance Commodity microprocessor systems use caches to increase memory bandwidth and reduce memory latencies. Typical latencies from processor to L1, L2, local, and remote memory are 3, 10, 50, and 200 cycles, respectively. Moreover, bandwidth falls off dramatically as memory distances increase. Programs that do not use cache effectively run many times slower than programs that do. When optimizing for cache, the biggest performance gains are achieved by accessing data in cache order and reusing data to amortize the overhead of cache misses. Secondary considerations are prefetching, associativity, and replacement; however, the understanding and analysis required to optimize for the latter are probably beyond the capabilities of the non-expert. Much can be gained simply by accessing data in the correct order and maximizing data reuse. 6 out of the 10 codes studied here benefited from such high level optimizations. Array Accesses The most important cache optimization is the most basic: accessing Fortran array elements in column order and C array elements in row order. Four of the ten codes—1, 2, 4, and 10—got it wrong. Compilers will restructure nested loops to optimize cache performance, but may not do so if the loop structure is too complex, or the loop body includes conditionals, complex addressing, or function calls. In code 1, the compiler failed to invert a key loop because of complex addressing do I = 0, 1010, delta_x IM = I - delta_x IP = I + delta_x do J = 5, 995, delta_x JM = J - delta_x JP = J + delta_x T1 = CA1(IP, J) + CA1(I, JP) T2 = CA1(IM, J) + CA1(I, JM) S1 = T1 + T2 - 4 * CA1(I, J) CA(I, J) = CA1(I, J) + D * S1 end do end do In code 2, the culprit is conditionals do I = 1, N do J = 1, N If (IFLAG(I,J) .EQ. 0) then T1 = Value(I, J-1) T2 = Value(I-1, J) T3 = Value(I, J) T4 = Value(I+1, J) T5 = Value(I, J+1) Value(I,J) = 0.25 * (T1 + T2 + T5 + T4) Delta = ABS(T3 - Value(I,J)) If (Delta .GT. MaxDelta) MaxDelta = Delta endif enddo enddo I fixed both programs by inverting the loops by hand. Code 10 has three-dimensional arrays and triply nested loops. The structure of the most computationally intensive loops is too complex to invert automatically or by hand. The only practical solution is to transpose the arrays so that the dimension accessed by the innermost loop is in cache order. The arrays can be transposed at construction or prior to entering a computationally intensive section of code. The former requires all array references to be modified, while the latter is cost effective only if the cost of the transpose is amortized over many accesses. I used the second approach to optimize code 10. Code 5 has four-dimensional arrays and loops are nested four deep. For all of the reasons cited above the compiler is not able to restructure three key loops. Assume C arrays and let the four dimensions of the arrays be i, j, k, and l. In the original code, the index structure of the three loops is L1: for i L2: for i L3: for i for l for l for j for k for j for k for j for k for l So only L3 accesses array elements in cache order. L1 is a very complex loop—much too complex to invert. I brought the loop into cache alignment by transposing the second and fourth dimensions of the arrays. Since the code uses a macro to compute all array indexes, I effected the transpose at construction and changed the macro appropriately. The dimensions of the new arrays are now: i, l, k, and j. L3 is a simple loop and easily inverted. L2 has a loop-carried scalar dependence in k. By promoting the scalar name that carries the dependence to an array, I was able to invert the third and fourth subloops aligning the loop with cache. Code 5 is by far the most difficult of the four codes to optimize for array accesses; but the knowledge required to fix the problems is no more than that required for the other codes. I would judge this code at the limits of, but not beyond, the capabilities of appropriately trained computational scientists. Array Strides When a cache miss occurs, a line (64 bytes) rather than just one word is loaded into the cache. If data is accessed stride 1, than the cost of the miss is amortized over 8 words. Any stride other than one reduces the cost savings. Two of the ten codes studied suffered from non-unit strides. The codes represent two important classes of "strided" codes. Code 1 employs a multi-grid algorithm to reduce time to convergence. The grids are every tenth, fifth, second, and unit element. Since time to convergence is inversely proportional to the distance between elements, coarse grids converge quickly providing good starting values for finer grids. The better starting values further reduce the time to convergence. The downside is that grids of every nth element, n > 1, introduce non-unit strides into the computation. In the original code, much of the savings of the multi-grid algorithm were lost due to this problem. I eliminated the problem by compressing (copying) coarse grids into continuous memory, and rewriting the computation as a function of the compressed grid. On convergence, I copied the final values of the compressed grid back to the original grid. The savings gained from unit stride access of the compressed grid more than paid for the cost of copying. Using compressed grids, the loop from code 1 included in the previous section becomes do j = 1, GZ do i = 1, GZ T1 = CA(i+0, j-1) + CA(i-1, j+0) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) S1 = T1 + T4 - 4 * CA1(i+0, j+0) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 enddo enddo where CA and CA1 are compressed arrays of size GZ. Code 7 traverses a list of objects selecting objects for later processing. The labels of the selected objects are stored in an array. The selection step has unit stride, but the processing steps have irregular stride. A fix is to save the parameters of the selected objects in temporary arrays as they are selected, and pass the temporary arrays to the processing functions. The fix is practical if the same parameters are used in selection as in processing, or if processing comprises a series of distinct steps which use overlapping subsets of the parameters. Both conditions are true for code 7, so I achieved significant improvement by copying parameters to temporary arrays during selection. Data reuse In the previous sections, we optimized for spatial locality. It is also important to optimize for temporal locality. Once read, a datum should be used as much as possible before it is forced from cache. Loop fusion and loop unrolling are two techniques that increase temporal locality. Unfortunately, both techniques increase register pressure—as loop bodies become larger, the number of registers required to hold temporary values grows. Once register spilling occurs, any gains evaporate quickly. For multiprocessors with small register sets or small caches, the sweet spot can be very small. In the ten codes presented here, I found no opportunities for loop fusion and only two opportunities for loop unrolling (codes 1 and 3). In code 1, unrolling the outer and inner loop one iteration increases the number of result values computed by the loop body from 1 to 4, do J = 1, GZ-2, 2 do I = 1, GZ-2, 2 T1 = CA1(i+0, j-1) + CA1(i-1, j+0) T2 = CA1(i+1, j-1) + CA1(i+0, j+0) T3 = CA1(i+0, j+0) + CA1(i-1, j+1) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) T5 = CA1(i+2, j+0) + CA1(i+1, j+1) T6 = CA1(i+1, j+1) + CA1(i+0, j+2) T7 = CA1(i+2, j+1) + CA1(i+1, j+2) S1 = T1 + T4 - 4 * CA1(i+0, j+0) S2 = T2 + T5 - 4 * CA1(i+1, j+0) S3 = T3 + T6 - 4 * CA1(i+0, j+1) S4 = T4 + T7 - 4 * CA1(i+1, j+1) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 CA(i+1, j+0) = CA1(i+1, j+0) + DD * S2 CA(i+0, j+1) = CA1(i+0, j+1) + DD * S3 CA(i+1, j+1) = CA1(i+1, j+1) + DD * S4 enddo enddo The loop body executes 12 reads, whereas as the rolled loop shown in the previous section executes 20 reads to compute the same four values. In code 3, two loops are unrolled 8 times and one loop is unrolled 4 times. Here is the before for (k = 0; k < NK[u]; k++) { sum = 0.0; for (y = 0; y < NY; y++) { sum += W[y][u][k] * delta[y]; } backprop[i++]=sum; } and after code for (k = 0; k < KK - 8; k+=8) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (y = 0; y < NY; y++) { sum0 += W[y][0][k+0] * delta[y]; sum1 += W[y][0][k+1] * delta[y]; sum2 += W[y][0][k+2] * delta[y]; sum3 += W[y][0][k+3] * delta[y]; sum4 += W[y][0][k+4] * delta[y]; sum5 += W[y][0][k+5] * delta[y]; sum6 += W[y][0][k+6] * delta[y]; sum7 += W[y][0][k+7] * delta[y]; } backprop[k+0] = sum0; backprop[k+1] = sum1; backprop[k+2] = sum2; backprop[k+3] = sum3; backprop[k+4] = sum4; backprop[k+5] = sum5; backprop[k+6] = sum6; backprop[k+7] = sum7; } for one of the loops unrolled 8 times. Optimizing for temporal locality is the most difficult optimization considered in this paper. The concepts are not difficult, but the sweet spot is small. Identifying where the program can benefit from loop unrolling or loop fusion is not trivial. Moreover, it takes some effort to get it right. Still, educating scientific programmers about temporal locality and teaching them how to optimize for it will pay dividends. Reducing instruction count Execution time is a function of instruction count. Reduce the count and you usually reduce the time. The best solution is to use a more efficient algorithm; that is, an algorithm whose order of complexity is smaller, that converges quicker, or is more accurate. Optimizing source code without changing the algorithm yields smaller, but still significant, gains. This paper considers only the latter because the intent is to study how much better codes can run if written by programmers schooled in basic code optimization techniques. The ten codes studied benefited from three types of "instruction reducing" optimizations. The two most prevalent were hoisting invariant memory and data operations out of inner loops. The third was eliminating unnecessary data copying. The nature of these inefficiencies is language dependent. Memory operations The semantics of C make it difficult for the compiler to determine all the invariant memory operations in a loop. The problem is particularly acute for loops in functions since the compiler may not know the values of the function's parameters at every call site when compiling the function. Most compilers support pragmas to help resolve ambiguities; however, these pragmas are not comprehensive and there is no standard syntax. To guarantee that invariant memory operations are not executed repetitively, the user has little choice but to hoist the operations by hand. The problem is not as severe in Fortran programs because in the absence of equivalence statements, it is a violation of the language's semantics for two names to share memory. Codes 3 and 5 are C programs. In both cases, the compiler did not hoist all invariant memory operations from inner loops. Consider the following loop from code 3 for (y = 0; y < NY; y++) { i = 0; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += delta[y] * I1[i++]; } } } Since dW[y][u] can point to the same memory space as delta for one or more values of y and u, assignment to dW[y][u][k] may change the value of delta[y]. In reality, dW and delta do not overlap in memory, so I rewrote the loop as for (y = 0; y < NY; y++) { i = 0; Dy = delta[y]; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += Dy * I1[i++]; } } } Failure to hoist invariant memory operations may be due to complex address calculations. If the compiler can not determine that the address calculation is invariant, then it can hoist neither the calculation nor the associated memory operations. As noted above, code 5 uses a macro to address four-dimensional arrays #define MAT4D(a,q,i,j,k) (double *)((a)->data + (q)*(a)->strides[0] + (i)*(a)->strides[3] + (j)*(a)->strides[2] + (k)*(a)->strides[1]) The macro is too complex for the compiler to understand and so, it does not identify any subexpressions as loop invariant. The simplest way to eliminate the address calculation from the innermost loop (over i) is to define a0 = MAT4D(a,q,0,j,k) before the loop and then replace all instances of *MAT4D(a,q,i,j,k) in the loop with a0[i] A similar problem appears in code 6, a Fortran program. The key loop in this program is do n1 = 1, nh nx1 = (n1 - 1) / nz + 1 nz1 = n1 - nz * (nx1 - 1) do n2 = 1, nh nx2 = (n2 - 1) / nz + 1 nz2 = n2 - nz * (nx2 - 1) ndx = nx2 - nx1 ndy = nz2 - nz1 gxx = grn(1,ndx,ndy) gyy = grn(2,ndx,ndy) gxy = grn(3,ndx,ndy) balance(n1,1) = balance(n1,1) + (force(n2,1) * gxx + force(n2,2) * gxy) * h1 balance(n1,2) = balance(n1,2) + (force(n2,1) * gxy + force(n2,2) * gyy)*h1 end do end do The programmer has written this loop well—there are no loop invariant operations with respect to n1 and n2. However, the loop resides within an iterative loop over time and the index calculations are independent with respect to time. Trading space for time, I precomputed the index values prior to the entering the time loop and stored the values in two arrays. I then replaced the index calculations with reads of the arrays. Data operations Ways to reduce data operations can appear in many forms. Implementing a more efficient algorithm produces the biggest gains. The closest I came to an algorithm change was in code 4. This code computes the inner product of K-vectors A(i) and B(j), 0 = i < N, 0 = j < M, for most values of i and j. Since the program computes most of the NM possible inner products, it is more efficient to compute all the inner products in one triply-nested loop rather than one at a time when needed. The savings accrue from reading A(i) once for all B(j) vectors and from loop unrolling. for (i = 0; i < N; i+=8) { for (j = 0; j < M; j++) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (k = 0; k < K; k++) { sum0 += A[i+0][k] * B[j][k]; sum1 += A[i+1][k] * B[j][k]; sum2 += A[i+2][k] * B[j][k]; sum3 += A[i+3][k] * B[j][k]; sum4 += A[i+4][k] * B[j][k]; sum5 += A[i+5][k] * B[j][k]; sum6 += A[i+6][k] * B[j][k]; sum7 += A[i+7][k] * B[j][k]; } C[i+0][j] = sum0; C[i+1][j] = sum1; C[i+2][j] = sum2; C[i+3][j] = sum3; C[i+4][j] = sum4; C[i+5][j] = sum5; C[i+6][j] = sum6; C[i+7][j] = sum7; }} This change requires knowledge of a typical run; i.e., that most inner products are computed. The reasons for the change, however, derive from basic optimization concepts. It is the type of change easily made at development time by a knowledgeable programmer. In code 5, we have the data version of the index optimization in code 6. Here a very expensive computation is a function of the loop indices and so cannot be hoisted out of the loop; however, the computation is invariant with respect to an outer iterative loop over time. We can compute its value for each iteration of the computation loop prior to entering the time loop and save the values in an array. The increase in memory required to store the values is small in comparison to the large savings in time. The main loop in Code 8 is doubly nested. The inner loop includes a series of guarded computations; some are a function of the inner loop index but not the outer loop index while others are a function of the outer loop index but not the inner loop index for (j = 0; j < N; j++) { for (i = 0; i < M; i++) { r = i * hrmax; R = A[j]; temp = (PRM[3] == 0.0) ? 1.0 : pow(r, PRM[3]); high = temp * kcoeff * B[j] * PRM[2] * PRM[4]; low = high * PRM[6] * PRM[6] / (1.0 + pow(PRM[4] * PRM[6], 2.0)); kap = (R > PRM[6]) ? high * R * R / (1.0 + pow(PRM[4]*r, 2.0) : low * pow(R/PRM[6], PRM[5]); < rest of loop omitted > }} Note that the value of temp is invariant to j. Thus, we can hoist the computation for temp out of the loop and save its values in an array. for (i = 0; i < M; i++) { r = i * hrmax; TEMP[i] = pow(r, PRM[3]); } [N.B. – the case for PRM[3] = 0 is omitted and will be reintroduced later.] We now hoist out of the inner loop the computations invariant to i. Since the conditional guarding the value of kap is invariant to i, it behooves us to hoist the computation out of the inner loop, thereby executing the guard once rather than M times. The final version of the code is for (j = 0; j < N; j++) { R = rig[j] / 1000.; tmp1 = kcoeff * par[2] * beta[j] * par[4]; tmp2 = 1.0 + (par[4] * par[4] * par[6] * par[6]); tmp3 = 1.0 + (par[4] * par[4] * R * R); tmp4 = par[6] * par[6] / tmp2; tmp5 = R * R / tmp3; tmp6 = pow(R / par[6], par[5]); if ((par[3] == 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp5; } else if ((par[3] == 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp4 * tmp6; } else if ((par[3] != 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp5; } else if ((par[3] != 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp4 * tmp6; } for (i = 0; i < M; i++) { kap = KAP[i]; r = i * hrmax; < rest of loop omitted > } } Maybe not the prettiest piece of code, but certainly much more efficient than the original loop, Copy operations Several programs unnecessarily copy data from one data structure to another. This problem occurs in both Fortran and C programs, although it manifests itself differently in the two languages. Code 1 declares two arrays—one for old values and one for new values. At the end of each iteration, the array of new values is copied to the array of old values to reset the data structures for the next iteration. This problem occurs in Fortran programs not included in this study and in both Fortran 77 and Fortran 90 code. Introducing pointers to the arrays and swapping pointer values is an obvious way to eliminate the copying; but pointers is not a feature that many Fortran programmers know well or are comfortable using. An easy solution not involving pointers is to extend the dimension of the value array by 1 and use the last dimension to differentiate between arrays at different times. For example, if the data space is N x N, declare the array (N, N, 2). Then store the problem’s initial values in (_, _, 2) and define the scalar names new = 2 and old = 1. At the start of each iteration, swap old and new to reset the arrays. The old–new copy problem did not appear in any C program. In programs that had new and old values, the code swapped pointers to reset data structures. Where unnecessary coping did occur is in structure assignment and parameter passing. Structures in C are handled much like scalars. Assignment causes the data space of the right-hand name to be copied to the data space of the left-hand name. Similarly, when a structure is passed to a function, the data space of the actual parameter is copied to the data space of the formal parameter. If the structure is large and the assignment or function call is in an inner loop, then copying costs can grow quite large. While none of the ten programs considered here manifested this problem, it did occur in programs not included in the study. A simple fix is always to refer to structures via pointers. Optimizing loop structures Since scientific programs spend almost all their time in loops, efficient loops are the key to good performance. Conditionals, function calls, little instruction level parallelism, and large numbers of temporary values make it difficult for the compiler to generate tightly packed, highly efficient code. Conditionals and function calls introduce jumps that disrupt code flow. Users should eliminate or isolate conditionls to their own loops as much as possible. Often logical expressions can be substituted for if-then-else statements. For example, code 2 includes the following snippet MaxDelta = 0.0 do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) if (Delta > MaxDelta) MaxDelta = Delta enddo enddo if (MaxDelta .gt. 0.001) goto 200 Since the only use of MaxDelta is to control the jump to 200 and all that matters is whether or not it is greater than 0.001, I made MaxDelta a boolean and rewrote the snippet as MaxDelta = .false. do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) MaxDelta = MaxDelta .or. (Delta .gt. 0.001) enddo enddo if (MaxDelta) goto 200 thereby, eliminating the conditional expression from the inner loop. A microprocessor can execute many instructions per instruction cycle. Typically, it can execute one or more memory, floating point, integer, and jump operations. To be executed simultaneously, the operations must be independent. Thick loops tend to have more instruction level parallelism than thin loops. Moreover, they reduce memory traffice by maximizing data reuse. Loop unrolling and loop fusion are two techniques to increase the size of loop bodies. Several of the codes studied benefitted from loop unrolling, but none benefitted from loop fusion. This observation is not too surpising since it is the general tendency of programmers to write thick loops. As loops become thicker, the number of temporary values grows, increasing register pressure. If registers spill, then memory traffic increases and code flow is disrupted. A thick loop with many temporary values may execute slower than an equivalent series of thin loops. The biggest gain will be achieved if the thick loop can be split into a series of independent loops eliminating the need to write and read temporary arrays. I found such an occasion in code 10 where I split the loop do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do into two disjoint loops do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) end do end do do i = 1, n do j = 1, m C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do Conclusions Over the course of the last year, I have had the opportunity to work with over two dozen academic scientific programmers at leading research universities. Their research interests span a broad range of scientific fields. Except for two programs that relied almost exclusively on library routines (matrix multiply and fast Fourier transform), I was able to improve significantly the single processor performance of all codes. Improvements range from 2x to 15.5x with a simple average of 4.75x. Changes to the source code were at a very high level. I did not use sophisticated techniques or programming tools to discover inefficiencies or effect the changes. Only one code was parallel despite the availability of parallel systems to all developers. Clearly, we have a problem—personal scientific research codes are highly inefficient and not running parallel. The developers are unaware of simple optimization techniques to make programs run faster. They lack education in the art of code optimization and parallel programming. I do not believe we can fix the problem by publishing additional books or training manuals. To date, the developers in questions have not studied the books or manual available, and are unlikely to do so in the future. Short courses are a possible solution, but I believe they are too concentrated to be much use. The general concepts can be taught in a three or four day course, but that is not enough time for students to practice what they learn and acquire the experience to apply and extend the concepts to their codes. Practice is the key to becoming proficient at optimization. I recommend that graduate students be required to take a semester length course in optimization and parallel programming. We would never give someone access to state-of-the-art scientific equipment costing hundreds of thousands of dollars without first requiring them to demonstrate that they know how to use the equipment. Yet the criterion for time on state-of-the-art supercomputers is at most an interesting project. Requestors are never asked to demonstrate that they know how to use the system, or can use the system effectively. A semester course would teach them the required skills. Government agencies that fund academic scientific research pay for most of the computer systems supporting scientific research as well as the development of most personal scientific codes. These agencies should require graduate schools to offer a course in optimization and parallel programming as a requirement for funding. About the Author John Feo received his Ph.D. in Computer Science from The University of Texas at Austin in 1986. After graduate school, Dr. Feo worked at Lawrence Livermore National Laboratory where he was the Group Leader of the Computer Research Group and principal investigator of the Sisal Language Project. In 1997, Dr. Feo joined Tera Computer Company where he was project manager for the MTA, and oversaw the programming and evaluation of the MTA at the San Diego Supercomputer Center. In 2000, Dr. Feo joined Sun Microsystems as an HPC application specialist. He works with university research groups to optimize and parallelize scientific codes. Dr. Feo has published over two dozen research articles in the areas of parallel parallel programming, parallel programming languages, and application performance.

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trouble running smooth animation in thread only when using key listener

- by heysuse renard

first time using a forum for coding help so sorry if i post this all wrong. i have more than a few classes i don't think screenManger or core holds the problem but i included them just incase. i got most of this code working through a set of tutorials. but a certain point started trying to do more on my own. i want to play the animation only when i'm moving my sprite. in my KeyTest class i am using threads to run the animation it used to work (poorly) but now not at all pluss it really gunks up my computer. i think it's because of the thread. im new to threads so i'm not to sure if i should even be using one in this situation or if its dangerous for my computer. the animation worked smoothly when i had the sprite bouce around the screen forever. the animation loop played with out stopping. i think the main problem is between the animationThread, Sprite, and keyTest classes, but itcould be more indepth. if someone could point me in the right direction for making the animation run smoothly when i push down a key and stop runing when i let off it would be greatly apriciated. i already looked at this Java a moving animation (sprite) obviously we were doing the same tutorial. but i feel my problem is slightly different. p.s. sorry for the typos. import java.awt.*; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import java.awt.image.BufferStrategy; import java.awt.image.BufferedImage; import java.util.ArrayList; import javax.swing.ImageIcon; import javax.swing.JFrame; public class KeyTest extends Core implements KeyListener { public static void main(String[] args) { new KeyTest().run(); } Sprite player1; Image hobo; Image background; animation hoboRun; animationThread t1; //init also calls init form superclass public void init() { super.init(); loadImages(); Window w = s.getFullScreenWindow(); w.setFocusTraversalKeysEnabled(false); w.addKeyListener(this); } //load method will go here. //load all pics need for animation and sprite public void loadImages() { background = new ImageIcon("\\\\STUART-PC\\Users\\Stuart\\workspace\\Gaming\\yellow square.jpg").getImage(); Image face1 = new ImageIcon("\\\\STUART-PC\\Users\\Stuart\\workspace\\Gaming\\circle.png").getImage(); Image face2 = new ImageIcon("\\\\STUART-PC\\Users\\Stuart\\workspace\\Gaming\\one eye.png").getImage(); hoboRun = new animation(); hoboRun.addScene(face1, 250); hoboRun.addScene(face2, 250); player1 = new Sprite(hoboRun); this.t1 = new animationThread(); this.t1.setAnimation(player1); } //key pressed public void keyPressed(KeyEvent e) { int keyCode = e.getKeyCode(); if (keyCode == KeyEvent.VK_ESCAPE) { stop(); } if (keyCode == KeyEvent.VK_RIGHT) { player1.setVelocityX(0.3f); try { this.t1.setRunning(true); Thread th1 = new Thread(this.t1); th1.start(); } catch (Exception ex) { System.out.println("noooo"); } } if (keyCode == KeyEvent.VK_LEFT) { player1.setVelocityX(-0.3f); try { this.t1.setRunning(true); Thread th1 = new Thread(this.t1); th1.start(); } catch (Exception ex) { System.out.println("noooo"); } } if (keyCode == KeyEvent.VK_DOWN) { player1.setVelocityY(0.3f); try { this.t1.setRunning(true); Thread th1 = new Thread(this.t1); th1.start(); } catch (Exception ex) { System.out.println("noooo"); } } if (keyCode == KeyEvent.VK_UP) { player1.setVelocityY(-0.3f); try { this.t1.setRunning(true); Thread th1 = new Thread(this.t1);; th1.start(); } catch (Exception ex) { System.out.println("noooo"); } } else { e.consume(); } } //keyReleased @SuppressWarnings("static-access") public void keyReleased(KeyEvent e) { int keyCode = e.getKeyCode(); if (keyCode == KeyEvent.VK_RIGHT || keyCode == KeyEvent.VK_LEFT) { player1.setVelocityX(0); try { this.t1.setRunning(false); } catch (Exception ex) { } } if (keyCode == KeyEvent.VK_UP || keyCode == KeyEvent.VK_DOWN) { player1.setVelocityY(0); try { this.t1.setRunning(false); } catch (Exception ex) { } } else { e.consume(); } } //last method from interface public void keyTyped(KeyEvent e) { e.consume(); } //draw public void draw(Graphics2D g) { Window w = s.getFullScreenWindow(); g.setColor(w.getBackground()); g.fillRect(0, 0, s.getWidth(), s.getHieght()); g.setColor(w.getForeground()); g.drawImage(player1.getImage(), Math.round(player1.getX()), Math.round(player1.getY()), null); } public void update(long timePassed) { player1.update(timePassed); } } abstract class Core { private static DisplayMode modes[] = { new DisplayMode(1600, 900, 64, 0), new DisplayMode(800, 600, 32, 0), new DisplayMode(800, 600, 24, 0), new DisplayMode(800, 600, 16, 0), new DisplayMode(800, 480, 32, 0), new DisplayMode(800, 480, 24, 0), new DisplayMode(800, 480, 16, 0),}; private boolean running; protected ScreenManager s; //stop method public void stop() { running = false; } public void run() { try { init(); gameLoop(); } finally { s.restoreScreen(); } } //set to full screen //set current background here public void init() { s = new ScreenManager(); DisplayMode dm = s.findFirstCompatibleMode(modes); s.setFullScreen(dm); Window w = s.getFullScreenWindow(); w.setFont(new Font("Arial", Font.PLAIN, 20)); w.setBackground(Color.GREEN); w.setForeground(Color.WHITE); running = true; } //main gameLoop public void gameLoop() { long startTime = System.currentTimeMillis(); long cumTime = startTime; while (running) { long timePassed = System.currentTimeMillis() - cumTime; cumTime += timePassed; update(timePassed); Graphics2D g = s.getGraphics(); draw(g); g.dispose(); s.update(); try { Thread.sleep(20); } catch (Exception ex) { } } } //update animation public void update(long timePassed) { } //draws to screen abstract void draw(Graphics2D g); } class animationThread implements Runnable { String name; boolean playing; Sprite a; //constructor takes input from keyboard public animationThread() { } //The run method for animation public void run() { long startTime = System.currentTimeMillis(); long cumTime = startTime; boolean test = getRunning(); while (test) { long timePassed = System.currentTimeMillis() - cumTime; cumTime += timePassed; test = getRunning(); } } public String getName() { return name; } public void setAnimation(Sprite a) { this.a = a; } public void setName(String name) { this.name = name; } public void setRunning(boolean running) { this.playing = running; } public boolean getRunning() { return playing; } } class animation { private ArrayList scenes; private int sceneIndex; private long movieTime; private long totalTime; //constructor public animation() { scenes = new ArrayList(); totalTime = 0; start(); } //add scene to ArrayLisy and set time for each scene public synchronized void addScene(Image i, long t) { totalTime += t; scenes.add(new OneScene(i, totalTime)); } public synchronized void start() { movieTime = 0; sceneIndex = 0; } //change scenes public synchronized void update(long timePassed) { if (scenes.size() > 1) { movieTime += timePassed; if (movieTime >= totalTime) { movieTime = 0; sceneIndex = 0; } while (movieTime > getScene(sceneIndex).endTime) { sceneIndex++; } } } //get animations current scene(aka image) public synchronized Image getImage() { if (scenes.size() == 0) { return null; } else { return getScene(sceneIndex).pic; } } //get scene private OneScene getScene(int x) { return (OneScene) scenes.get(x); } //Private Inner CLASS////////////// private class OneScene { Image pic; long endTime; public OneScene(Image pic, long endTime) { this.pic = pic; this.endTime = endTime; } } } class Sprite { private animation a; private float x; private float y; private float vx; private float vy; //Constructor public Sprite(animation a) { this.a = a; } //change position public void update(long timePassed) { x += vx * timePassed; y += vy * timePassed; } public void startAnimation(long timePassed) { a.update(timePassed); } //get x position public float getX() { return x; } //get y position public float getY() { return y; } //set x public void setX(float x) { this.x = x; } //set y public void setY(float y) { this.y = y; } //get sprite width public int getWidth() { return a.getImage().getWidth(null); } //get sprite height public int getHeight() { return a.getImage().getHeight(null); } //get horizontal velocity public float getVelocityX() { return vx; } //get vertical velocity public float getVelocityY() { return vx; } //set horizontal velocity public void setVelocityX(float vx) { this.vx = vx; } //set vertical velocity public void setVelocityY(float vy) { this.vy = vy; } //get sprite / image public Image getImage() { return a.getImage(); } } class ScreenManager { private GraphicsDevice vc; public ScreenManager() { GraphicsEnvironment e = GraphicsEnvironment.getLocalGraphicsEnvironment(); vc = e.getDefaultScreenDevice(); } //get all compatible DM public DisplayMode[] getCompatibleDisplayModes() { return vc.getDisplayModes(); } //compares DM passed into vc DM and see if they match public DisplayMode findFirstCompatibleMode(DisplayMode modes[]) { DisplayMode goodModes[] = vc.getDisplayModes(); for (int x = 0; x < modes.length; x++) { for (int y = 0; y < goodModes.length; y++) { if (displayModesMatch(modes[x], goodModes[y])) { return modes[x]; } } } return null; } //get current DM public DisplayMode getCurrentDisplayMode() { return vc.getDisplayMode(); } //checks if two modes match each other public boolean displayModesMatch(DisplayMode m1, DisplayMode m2) { if (m1.getWidth() != m2.getWidth() || m1.getHeight() != m2.getHeight()) { return false; } if (m1.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && m2.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && m1.getBitDepth() != m2.getBitDepth()) { return false; } if (m1.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && m2.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && m1.getRefreshRate() != m2.getRefreshRate()) { return false; } return true; } //make frame full screen public void setFullScreen(DisplayMode dm) { JFrame f = new JFrame(); f.setUndecorated(true); f.setIgnoreRepaint(true); f.setResizable(false); vc.setFullScreenWindow(f); if (dm != null && vc.isDisplayChangeSupported()) { try { vc.setDisplayMode(dm); } catch (Exception ex) { } } f.createBufferStrategy(2); } //sets graphics object = this return public Graphics2D getGraphics() { Window w = vc.getFullScreenWindow(); if (w != null) { BufferStrategy s = w.getBufferStrategy(); return (Graphics2D) s.getDrawGraphics(); } else { return null; } } //updates display public void update() { Window w = vc.getFullScreenWindow(); if (w != null) { BufferStrategy s = w.getBufferStrategy(); if (!s.contentsLost()) { s.show(); } } } //returns full screen window public Window getFullScreenWindow() { return vc.getFullScreenWindow(); } //get width of window public int getWidth() { Window w = vc.getFullScreenWindow(); if (w != null) { return w.getWidth(); } else { return 0; } } //get height of window public int getHieght() { Window w = vc.getFullScreenWindow(); if (w != null) { return w.getHeight(); } else { return 0; } } //get out of full screen public void restoreScreen() { Window w = vc.getFullScreenWindow(); if (w != null) { w.dispose(); } vc.setFullScreenWindow(null); } //create image compatible with monitor public BufferedImage createCopatibleImage(int w, int h, int t) { Window win = vc.getFullScreenWindow(); if (win != null) { GraphicsConfiguration gc = win.getGraphicsConfiguration(); return gc.createCompatibleImage(w, h, t); } return null; } }

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Rails link to PDF version of show.html.erb

- by Danny McClelland

Hi Everyone, I have created a pdf version of our rails application using the Prawn plugin, the page in question is part of the Kase model - the link to the kase is /kases/1 and the link to the pdf version is /kases/1.pdf. How can I add a link within the show.html.erb to the PDF file so whichever page is being viewed it updates the URL to the correct case id? <% content_for :header do -%> <%=h @kase.jobno %> | <%=h @kase.casesubject %> <% end -%>  <% content_for :sidebar do -%> <% if @kase.avatar.exists? then %> <%= image_tag @kase.avatar.url %> <% else %> <p style="font-size:smaller"> You can upload an icon for this case that will display here. Usually this would be for the year number icon for easy recognition.</p> <% end %> <% end %>  <ul id="kases_showlist"> <li>Date Instructed: <span><%=h @kase.dateinstructed %></span></li> <li>Client Company: <span><%=h @kase.clientcompanyname %></span></li> <li>Client Reference: <span><%=h @kase.clientref %></span></li> <li>Case Subject: <span><%=h @kase.casesubject %></span></li> <li>Transport<span><%=h @kase.transport %></span></li> <li>Goods<span><%=h @kase.goods %></span></li> <li>Case Status: <span><%=h @kase.kase_status %></span></li> <li>Client Company Address: <span class="address"><%=h @kase.clientcompanyaddress %></span></li> <li>Client Company Fax: <span><%=h @kase.clientcompanyfax %></span></li> <li>Case Handler: <span><%=h @kase.casehandlername %></span></li> <li>Case Handler Tel: <span><%=h @kase.casehandlertel %></span></li> <li>Case Handler Email: <span><%=h @kase.casehandleremail %></span></li> <li>Claimant Name: <span><%=h @kase.claimantname %></span></li> <li>Claimant Address: <span class="address"><%=h @kase.claimantaddress %></span></li> <li>Claimant Contact: <span><%=h @kase.claimantcontact %></span></li> <li>Claimant Tel: <span><%=h @kase.claimanttel %></span></li> <li>Claiment Mob: <span><%=h @kase.claimantmob %></span></li> <li>Claiment Email: <span><%=h @kase.claimantemail %></span></li> <li>Claimant URL: <span><%=h @kase.claimanturl %></span></li> <li>Comments: <span><%=h @kase.comments %></span></li> </ul>  <div id="kase_finances"> <div class="js_option"> <h2>Financial Options</h2><p class="finance_showhide"><%= link_to_function "Show","Element.show('finance_showhide');" %> / <%= link_to_function "Hide","Element.hide('finance_showhide');" %></p> </div> <div id="finance_showhide" style="display:none"> <ul id="kases_new_finance"> <li>Invoice Number<span><%=h @kase.invoicenumber %></span></li> <li>Net Amount<span><%=h @kase.netamount %></span></li> <li>VAT<span><%=h @kase.vat %></span></li> <li>Gross Amount<span><%=h @kase.grossamount %></span></li> <li>Date Closed<span><%=h @kase.dateclosed %></span></li> <li>Date Paid<span><%=h @kase.datepaid %></span></li> </ul></div> </div>  <%= link_to 'Edit Case', edit_kase_path(@kase) %> | <%= link_to 'Back', kases_path %> | <a href="#">Top</a> <div style="width:120%; height: 50px; background-color: black; margin: 10px 0 0 -19px; padding: 0; background-color: #d4d4d4;"> </div> <div class="js_option_kaseemails"> <%= link_to_function "Show", "Element.show('newinstructionemail1');" %> / <%= link_to_function "Hide", "Element.hide('newinstructionemail1');" %> </div> <h3>New Instruction Email</h3> <div id="newinstructionemail1" style="display:none"> <p class="kase_email_output"> Hi,<br /> <br /> Many thanks for your instructions in the subject matter.<br /> <br /> We have allocated reference number <%=h @kase.jobno %> to the above claim.<br /> <br /> We have started our inquiries and will be in touch.<br /> <br /> Best Regards,<br /> <br /> <strong><%=h current_user.name %></strong> <br /> McClelland & Co<br /> PO Box 149<br /> Southport<br /> PR8 4GZ<br /> <br /> Tel: +(0) 1704 569871<br /> Fax: +(0) 1704 562234<br /> Mob: <%=h current_user.mobile %><br /> E-mail: <%= current_user.email %><br /> <br /> This e-mail and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you receive this e-mail in error please notify the originator of the message. <br /><br /> McClelland & Co has taken every reasonable precaution to ensure that any attachment to this e-mail has been checked for viruses but it is strongly recommended that you carry out your own virus check before opening any attachment. McClelland & Co cannot accept liability for any damage sustained as a result of software virus infection. </p> <%= link_to 'Edit Case', edit_kase_path(@kase) %> | <%= link_to 'Back', kases_path %> | <a href="#">Top</a> </div> <div style="width:120%; height: 20px; background-color: black; margin: 10px 0 0 -19px; padding: 0; background-color: #d4d4d4;"> </div> <div class="js_option_kaseemails"> <%= link_to_function "Show", "Element.show('newinstructionemail');" %> / <%= link_to_function "Hide", "Element.hide('newinstructionemail');" %> </div> <h3>New Instruction Email</h3> <div id="newinstructionemail" style="display:none"> <p class="kase_email_output"> Hi,<br /> <br /> Many thanks for your instructions in the subject matter.<br /> <br /> We have allocated reference number <%=h @kase.jobno %> to the above claim.<br /> <br /> We have started our inquiries and will be in touch.<br /> <br /> Best Regards,<br /> <br /> <strong><%=h current_user.name %></strong> <br /> McClelland & Co<br /> PO Box 149<br /> Southport<br /> PR8 4GZ<br /> <br /> Tel: +(0) 1704 569871<br /> Fax: +(0) 1704 562234<br /> Mob: <%=h current_user.mobile %><br /> E-mail: <%= current_user.email %><br /> <br /> This e-mail and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you receive this e-mail in error please notify the originator of the message. <br /><br /> McClelland & Co has taken every reasonable precaution to ensure that any attachment to this e-mail has been checked for viruses but it is strongly recommended that you carry out your own virus check before opening any attachment. McClelland & Co cannot accept liability for any damage sustained as a result of software virus infection. </p> <%= link_to 'Edit Case', edit_kase_path(@kase) %> | <%= link_to 'Back', kases_path %> | <a href="#">Top</a> </div> <div style="width:120%; height: 20px; background-color: black; margin: 10px 0 0 -19px; padding: 0; background-color: #d4d4d4;"> </div> <div class="js_option_kaseemails"> <%= link_to_function "Show", "Element.show('newinstructionemail2');" %> / <%= link_to_function "Hide", "Element.hide('newinstructionemail2');" %> </div> <h3>New Instruction Email</h3> <div id="newinstructionemail2" style="display:none;"> <p class="kase_email_output"> Hi,<br /> <br /> Many thanks for your instructions in the subject matter.<br /> <br /> We have allocated reference number <%=h @kase.jobno %> to the above claim.<br /> <br /> We have started our inquiries and will be in touch.<br /> <br /> Best Regards,<br /> <br /> <strong><%=h current_user.name %></strong> <br /> McClelland & Co<br /> PO Box 149<br /> Southport<br /> PR8 4GZ<br /> <br /> Tel: +(0) 1704 569871<br /> Fax: +(0) 1704 562234<br /> Mob: <%=h current_user.mobile %><br /> E-mail: <%= current_user.email %><br /> <br /> This e-mail and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you receive this e-mail in error please notify the originator of the message. <br /><br /> McClelland & Co has taken every reasonable precaution to ensure that any attachment to this e-mail has been checked for viruses but it is strongly recommended that you carry out your own virus check before opening any attachment. McClelland & Co cannot accept liability for any damage sustained as a result of software virus infection. </p> <%= link_to 'Edit Case', edit_kase_path(@kase) %> | <%= link_to 'Back', kases_path %> | <a href="#">Top</a> </div> Thanks, Danny

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