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  • Struts2 converting empty string parameter to an "int"

    - by Kyle Partridge
    How does one convert an empty string to an int using Struts2. When the application encounters this parameter with no value, like from an empty text field, it throws the following exception. java.lang.NoSuchMethodException: com.XXXXXXXXXXXX.setID([Ljava.lang.String;) Where ID is an integer, and the URL is: Something.action?ID=&other=rawr Is there a way to do this without using an Integer (class)? Do I have to write a type converter?

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  • Object slicing in Java.

    - by ferrari fan
    Can you take a subclass object and somehow convert it to an object of the same type as the parent class and at the same time slicing all the fields that are not part of the parent class? I know you can do this in C++, but I have no idea how to do it in Java.

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  • Displaying a list of objects with Views - Drupal

    - by RadiantHex
    Hi folks, I'll briefly explain what I'm trying to do: I need to sort a set of content-types within a paginated page. Also I need to add filtering to the page, for example each content-type should have a set of tags and the filter needs to filter through these tags. This is a basic mockup of what this page consists of: I'm finding it quite hard figuring out the best way to do it, and if this can be done. Help would be very much appreciated!!

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  • What database field should this be?

    - by alex
    I have a table called "Event". A column has "duration"--which is...how long that event lasts. What database type should this be? Integer? (in seconds)? In the future, I will do statements such as: If now() > event.duration THEN don't display the event.

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  • C# Test if an object is an Enum

    - by Aran Mulholland
    I would like to know if 'theObject' is an enum (of any enum type) foreach (var item in Enum.GetValues(theObject.GetType())) { //make sure we have all the enumeration values in the collection if (this.ValuesCollection.Contains(item)) { } else { this.ValuesCollection.Add(item); } Console.WriteLine(item.ToString()); Console.WriteLine(item.GetType().ToString()); }

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  • NHibernate and objects with value-semantics

    - by Groo
    Problem: If I pass a class with value semantics (Equals method overridden) to NHibernate, NHibernate tries to save it to db even though it just saved an entity equal by value (but not by reference) to the database. What am I doing wrong? Here is a simplified example model for my problem: Let's say I have a Person entity and a City entity. One thread (producer) is creating new Person objects which belong to a specific existing City, and another thread (consumer) is saving them to a repository (using NHibernate as DAL). Since there is lot of objects being flushed at a time, I am using Guid.Comb id's to ensure that each insert is made using a single SQL command. City is an object with value-type semantics (equal by name only -- for this example purposes only): public class City : IEquatable<City> { public virtual Guid Id { get; private set; } public virtual string Name { get; set; } public virtual bool Equals(City other) { if (other == null) return false; return this.Name == other.Name; } public override bool Equals(object obj) { return Equals(obj as City); } public override int GetHashCode() { return this.Name.GetHashCode(); } } Fluent NH mapping is something like: public class PersonMap : ClassMap<Person> { public PersonMap() { Id(x => x.Id) .GeneratedBy.GuidComb(); References(x => x.City) .Cascade.SaveUpdate(); } } public class CityMap : ClassMap<City> { public CityMap() { Id(x => x.Id) .GeneratedBy.GuidComb(); Map(x => x.Name); } } Right now (with my current NHibernate mapping config), my consumer thread maintains a dictionary of cities and replaces their references in incoming person objects (otherwise NHibernate will see a new, non-cached City object and try to save it as well), and I need to do it for every produced Person object. Since I have implemented City class to behave like a value type, I hoped that NHibernate would compare Cities by value and not try to save them each time -- i.e. I would only need to do a lookup once per session and not care about them anymore. Is this possible, and if yes, what am I doing wrong here?

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  • decltype, result_of, or typeof?

    - by Neil G
    I have: class A { public: B toCPD() const; And: template<typename T> class Ev { public: typedef result_of(T::toCPD()) D; After instantiating Ev<A>, the compiler says: meta.h:12: error: 'T::toCPD' is not a type neither decltype nor typeof work either.

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  • AS3: How can I require a method argument to implement multiple interfaces?

    - by Anders
    The argument to my method func() must implement the two unrelated interfaces IFoo and IBar. Is there a better way of doing this than declaring another interface only for this purpose that inherits from IFoo and IBar and using that interface as the argument type? public interface IFooBar implements IFoo, IBar { } public function func(arg:IFooBar):void { } I'm developing for Flash Player 9.

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  • Can the .NET MethodInfo cache be cleared or disabled?

    - by Anton
    Per MSDN, calling Type.GetMethods() stores reflected method information in a MemberInfo cache so the expensive operation doesn't have to be performed again. I have an application that scans assemblies/types, looking for methods that match a given specification. The problem is that memory consumption increases significantly (especially with large numbers of referenced assemblies) since .NET hangs onto the method metadata. Is there any way to clear or disable this MemberInfo cache?

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  • Java monospace draw string

    - by javaAmator
    Hello! How can I draw a String in Java (using Graphics2d) in monospace mode? I have a font that looks like LCD screen font, and I want to draw something like LCD label. I am using Digital 7 Mono font. Do you know where I can find another font that will be monospace and lcd (I wan to type only digitals)?

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  • PHP: constant as variable in function

    - by m4recek
    I'm trying to use constant as a function paramter, is it possible to check type of this constant. Example of what I want: class ApiError { const INVALID_REQUEST = 200; } class Response { public function status(ApiError $status) { //function code here } } USE: $response = new Response(); $response->status(ApiError::INVALID_REQUEST); This shoud check that given $status is constant of class ApiError. Is something like this possible?

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  • C++ STL: Trouble with iterators

    - by Rosarch
    I'm having a beginner problem: bool _isPalindrome(const string& str) { return _isPalindrome(str.begin(), str.end()); // won't compile } bool _isPalindrome(string::iterator begin, string::iterator end) { return begin == end || *begin == *end && _isPalindrome(++begin, --end); } What am I doing wrong here? Why doesn't str.begin() get type checked to be a string::iterator?

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  • JSF 2.0: java based custom component + html table + facelets = data model not updated

    - by mikic
    Hi, I'm having problems getting the data model of a HtmlDataTable to be correctly updated by JSF 2.0 and Facelets. I have created a custom Java-based component that extends HtmlDataTable and dynamically adds columns in the encodeBegin method. @Override public void encodeBegin(FacesContext context) throws IOException { if (this.findComponent("c0") == null) { for (int i = 0; i < 3; i++) { HtmlColumn myNewCol = new HtmlColumn(); myNewCol.setId("c" + i); HtmlInputText myNewText = new HtmlInputText(); myNewText.setId("t" + i); myNewText.setValue("#{row[" + i + "]}"); myNewCol.getChildren().add(myNewText); this.getChildren().add(myNewCol); } } super.encodeBegin(context); } My test page contains the following <h:form id="fromtb"> <test:MatrixTest id="tb" var="row" value="#{MyManagedBean.model}"> </test:MatrixTest> <h:commandButton id="btn" value="Set" action="#{MyManagedBean.mergeInput}"/> </h:form> <h:outputText id="mergedInput" value="#{MyManagedBean.mergedInput}"/> My managed bean class contains the following @ManagedBean(name="MyManagedBean") @SessionScoped public class MyManagedBean { private List model = null; private String mergedInput = null; public MyManagedBean() { model = new ArrayList(); List myFirst = new ArrayList(); myFirst.add(""); myFirst.add(""); myFirst.add(""); model.add(myFirst); List mySecond = new ArrayList(); mySecond.add(""); mySecond.add(""); mySecond.add(""); model.add(mySecond); } public String mergeInput() { StringBuffer myMergedInput = new StringBuffer(); for (Object object : model) { myMergedInput.append(object); } setMergedInput(myMergedInput.toString()); return null; } public List getModel() { return model; } public void setModel(List model) { this.model = model; } public String getMergedInput() { return mergedInput; } public void setMergedInput(String mergedInput) { this.mergedInput = mergedInput; } When invoked, the page is correctly rendered with a table made of 3 columns (added at runtime) and 2 rows (as my data model has 2 rows). However when the user enter some data in the input fields and then click the submit button, the model is not correctly updated and therefore the mergeInput() method creates a sequence of empty strings which is rendered on the same page. I have added some logging to the decode() method of my custom component and I can see that the parameters entered by the user are being posted back with the request, however these parameters are not used to update the data model. If I update the encodeBegin() method of my custom component as follow @Override public void encodeBegin(FacesContext context) throws IOException { super.encodeBegin(context); } and I update the test page as follow <test:MatrixTest id="tb" var="row" value="#{MyManagedBean.model}"> <h:column id="c0"><h:inputText id="t0" value="#{row[0]}"/></h:column> <h:column id="c1"><h:inputText id="t1" value="#{row[1]}"/></h:column> <h:column id="c2"><h:inputText id="t2" value="#{row[2]}"/></h:column> </test:MatrixTest> the page is correctly rendered and this time when the user enters data and submits the form, the underlying data model is correctly updated and the mergeInput() method creates a sequence of strings with the user data. Why does the test case with columns declared in the facelet page works correctly (ie the data model is correctly updated by JSF) where the same does not happen when the columns are created at runtime using the encodeBegin() method? Is there any method I need to invoke or interface I need to extend in order to ensure the data model is correctly updated? I am using this test case to address the issue that is appearing in a much more complex component, therefore I can't achieve the same functionality using a facelet composite component. Please note that this has been done using NetBeans 6.8, JRE 1.6.0u18, GlassFish 3.0. Thanks for your help.

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  • WPF Xaml Custom Styling Selected Item Style in a ListBox

    - by John Batdorf
    I have a list box that scrolls images horizontally. I have the following XAML I used blend to create it. It originally had a x:Key on the Style TaregetType line, MSDN said to remove it, as I was getting errors on that. Now I'm getting this error: Error 3 Operation is not valid while ItemsSource is in use. Access and modify elements with ItemsControl.ItemsSource instead. I don't understand how to apply all of this junk that way, I've tried several thing, nothing is working. My goal is to have the selected item's background be white, not blue. Seems like a lot of work for something so small! Thanks. <ListBox ItemsSource="{Binding Source={StaticResource WPFApparelCollection}}" Grid.Row="1" Margin="2,26,2,104" ScrollViewer.VerticalScrollBarVisibility="Hidden" ScrollViewer.HorizontalScrollBarVisibility="Hidden" SelectionMode="Single" x:Name="list1" MouseLeave="List1_MouseLeave" MouseMove="List1_MouseMove" Style="{DynamicResource ListBoxStyle1}" > <Style TargetType="{x:Type ListBoxItem}"> <Setter Property="Background" Value="Transparent"/> <Setter Property="HorizontalContentAlignment" Value="{Binding Path=HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/> <Setter Property="VerticalContentAlignment" Value="{Binding Path=VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/> <Setter Property="Padding" Value="2,0,0,0"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type ListBoxItem}"> <Border x:Name="Bd" SnapsToDevicePixels="true" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}"> <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/> </Border> <ControlTemplate.Triggers> <Trigger Property="IsSelected" Value="true"> <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}"/> <Setter Property="Background" TargetName="Bd" Value="#FFFFFFFF"/> </Trigger> <MultiTrigger> <MultiTrigger.Conditions> <Condition Property="IsSelected" Value="true"/> <Condition Property="Selector.IsSelectionActive" Value="false"/> </MultiTrigger.Conditions> <Setter Property="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/> <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/> </MultiTrigger> <Trigger Property="IsEnabled" Value="false"> <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style> <ListBox.ItemsPanel> <ItemsPanelTemplate> <VirtualizingStackPanel Orientation="Horizontal" IsItemsHost="True" /> </ItemsPanelTemplate> </ListBox.ItemsPanel> <ListBox.ItemTemplate> <DataTemplate> <Image Source="{Binding Image}" /> </DataTemplate> </ListBox.ItemTemplate> </ListBox>

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  • Very slow KVM in Ubuntu 12.04

    - by Guy Fawkes
    I use Ubuntu 12.04 64-bit and KVM, my CPU is Core i5 3.3 GHz and I have 8 GB of DDR3 RAM. I run Windows 7 in KVM and it's extremely slow. My co-worker use Debian on the same PC configuration and can run Windows 7 extremely fast! Where can be my problem? sudo cat /etc/libvirt/qemu/windows.xml <!-- WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE OVERWRITTEN AND LOST. Changes to this xml configuration should be made using: virsh edit windows or other application using the libvirt API. --> <domain type='kvm'> <name>windows</name> <uuid>5c685175-baea-0ca6-591f-8269d923ffb8</uuid> <memory>2097152</memory> <currentMemory>2097152</currentMemory> <vcpu>1</vcpu> <os> <type arch='x86_64' machine='pc-1.0'>hvm</type> <boot dev='hd'/> </os> <features> <acpi/> <apic/> <pae/> </features> <clock offset='localtime'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <devices> <emulator>/usr/bin/kvm</emulator> <disk type='file' device='disk'> <driver name='qemu' type='raw'/> <source file='/var/lib/libvirt/images/windows.img'/> <target dev='hda' bus='ide'/> <address type='drive' controller='0' bus='0' unit='0'/> </disk> <controller type='ide' index='0'> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/> </controller> <interface type='network'> <mac address='52:54:00:94:63:91'/> <source network='default'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> <serial type='pty'> <target port='0'/> </serial> <console type='pty'> <target type='serial' port='0'/> </console> <input type='tablet' bus='usb'/> <input type='mouse' bus='ps2'/> <graphics type='vnc' port='-1' autoport='yes'/> <sound model='ich6'> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </sound> <video> <model type='vga' vram='262144' heads='1'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/> </video> <memballoon model='virtio'> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </memballoon> </devices> </domain>

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  • Sysprep and Capture task sequence failing using MDT 2010

    - by Nic Young
    I have created a Windows Deployment Services server in Windows 2008 R2. When I originally set it up I was able to successfully use MDT 2010 to create my boot images as well as creating task sequences that would sysprep and capture, and deploy my custom .wim files. Everything was working perfectly. About a month later I boot up my Windows 7 x86 image and run Windows updates to keep my image up to date. I then go and run my sysprep and capture task sequence and I get the following errors: I searched online for the cause of this error message and it just seems to be a generic permission denied type of error message. I then decided to completely rebuild my VM image from scratch and try again. I am still getting the same error messages as before. The following is what I have tried troubleshooting this issue: Troubleshooting: I have ensured that that UAC and the firewall is turned completely off when trying to capture the image. I have tried recreating the task sequence and making sure that the deployment share is updated. I have ensured that the local Administrator account is enabled and has the same password as specified in the task sequence. I have tried joining the computer to the domain and running the task sequence and I get a different error: I have attempted to run the script from the command prompt with "Run as Administrator" and I still receive the same errors above. For testing purposes I have ensured that Everyone has read/write access to my deployment share. I have spent days on trying to resolve this to no avail. Any ideas? EDIT: Below is the log info from C:\Windows\Deploymentlogs\BDD.log as requested. <![LOG[LTI Windows PE applied successfully]LOG]!><time="11:48:34.000+000" date="07-25-2012" component="LTIApply" context="" type="1" thread="" file="LTIApply"> <![LOG[LTIApply processing completed successfully.]LOG]!><time="11:48:34.000+000" date="07-25-2012" component="LTIApply" context="" type="1" thread="" file="LTIApply"> <![LOG[Microsoft Deployment Toolkit version: 6.0.2223.0]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="ZTIDrivers" context="" type="1" thread="" file="ZTIDrivers"> <![LOG[The task sequencer log is located at C:\Users\nicy\AppData\Local\Temp\SMSTSLog\SMSTS.LOG. For task sequence failures, please consult this log.]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="ZTIDrivers" context="" type="1" thread="" file="ZTIDrivers"> <![LOG[Processing drivers for an X86 operating system.]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="ZTIDrivers" context="" type="1" thread="" file="ZTIDrivers"> <![LOG[TargetOS is the current SystemDrive]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="ZTIDrivers" context="" type="1" thread="" file="ZTIDrivers"> <![LOG[Property DriverCleanup is now = DONE]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="ZTIDrivers" context="" type="1" thread="" file="ZTIDrivers"> <![LOG[Compare Image processor Type with Original [X86] = [X86].]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="ZTIDrivers" context="" type="1" thread="" file="ZTIDrivers"> <![LOG[Prepare machine for Sysprep.]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="ZTIDrivers" context="" type="1" thread="" file="ZTIDrivers"> <![LOG[No driver actions can be taken for OS Images installed from *.wim files.]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="ZTIDrivers" context="" type="1" thread="" file="ZTIDrivers"> <![LOG[ZTIDrivers processing completed successfully.]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="ZTIDrivers" context="" type="1" thread="" file="ZTIDrivers"> <![LOG[Command completed, return code = -2147467259]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="LiteTouch" context="" type="1" thread="" file="LiteTouch"> <![LOG[Litetouch deployment failed, Return Code = -2147467259 0x80004005]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="LiteTouch" context="" type="3" thread="" file="LiteTouch"> <![LOG[For more information, consult the task sequencer log ...\SMSTS.LOG.]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="LiteTouch" context="" type="1" thread="" file="LiteTouch"> <![LOG[Property RetVal is now = -2147467259]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="LiteTouch" context="" type="1" thread="" file="LiteTouch"> <![LOG[Unable to copy log to the network as no SLShare value was specified.]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="LiteTouch" context="" type="1" thread="" file="LiteTouch"> <![LOG[CleanStartItems Complete]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="LiteTouch" context="" type="1" thread="" file="LiteTouch"> <![LOG[Unregistering TSCore.dll.]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="LiteTouch" context="" type="1" thread="" file="LiteTouch"> <![LOG[About to run command: wscript.exe "\\server\deploymentshare$\Scripts\LTICleanup.wsf"]LOG]!><time="11:48:35.000+000" date="07-25-2012" component="LiteTouch" context="" type="1" thread="" file="LiteTouch"> <![LOG[Microsoft Deployment Toolkit version: 6.0.2223.0]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup"> <![LOG[Removing AutoAdminLogon registry entries]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup"> <![LOG[VSSMaxSize not specified using 5% of volume.]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup"> <![LOG[Logs contained 7 errors and 0 warnings.]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup"> <![LOG[Stripping BDD commands from unattend.xml template.]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup"> <![LOG[Modified unattend.xml saved to C:\windows\panther\unattend.xml]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup"> <![LOG[Checking mapped network drive.]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup"> <![LOG[testing drive Z: mapped to \\server\deploymentshare$]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup"> <![LOG[Disconnecting drive Z: mapped to \\server\deploymentshare$]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup"> <![LOG[Cleaning up C:\MININT directory.]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup"> <![LOG[Cleaning up TOOLS, SCRIPTS, and PACKAGES directories.]LOG]!><time="11:48:36.000+000" date="07-25-2012" component="LTICleanup" context="" type="1" thread="" file="LTICleanup">

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  • Creating a dynamic proxy generator with c# – Part 3 – Creating the constructors

    - by SeanMcAlinden
    Creating a dynamic proxy generator with c# – Part 1 – Creating the Assembly builder, Module builder and caching mechanism Creating a dynamic proxy generator with c# – Part 2 – Interceptor Design For the latest code go to http://rapidioc.codeplex.com/ When building our proxy type, the first thing we need to do is build the constructors. There needs to be a corresponding constructor for each constructor on the passed in base type. We also want to create a field to store the interceptors and construct this list within each constructor. So assuming the passed in base type is a User<int, IRepository> class, were looking to generate constructor code like the following:   Default Constructor public User`2_RapidDynamicBaseProxy() {     this.interceptors = new List<IInterceptor<User<int, IRepository>>>();     DefaultInterceptor<User<int, IRepository>> item = new DefaultInterceptor<User<int, IRepository>>();     this.interceptors.Add(item); }     Parameterised Constructor public User`2_RapidDynamicBaseProxy(IRepository repository1) : base(repository1) {     this.interceptors = new List<IInterceptor<User<int, IRepository>>>();     DefaultInterceptor<User<int, IRepository>> item = new DefaultInterceptor<User<int, IRepository>>();     this.interceptors.Add(item); }   As you can see, we first populate a field on the class with a new list of the passed in base type. Construct our DefaultInterceptor class. Add the DefaultInterceptor instance to our interceptor collection. Although this seems like a relatively small task, there is a fair amount of work require to get this going. Instead of going through every line of code – please download the latest from http://rapidioc.codeplex.com/ and debug through. In this post I’m going to concentrate on explaining how it works. TypeBuilder The TypeBuilder class is the main class used to create the type. You instantiate a new TypeBuilder using the assembly module we created in part 1. /// <summary> /// Creates a type builder. /// </summary> /// <typeparam name="TBase">The type of the base class to be proxied.</typeparam> public static TypeBuilder CreateTypeBuilder<TBase>() where TBase : class {     TypeBuilder typeBuilder = DynamicModuleCache.Get.DefineType         (             CreateTypeName<TBase>(),             TypeAttributes.Class | TypeAttributes.Public,             typeof(TBase),             new Type[] { typeof(IProxy) }         );       if (typeof(TBase).IsGenericType)     {         GenericsHelper.MakeGenericType(typeof(TBase), typeBuilder);     }       return typeBuilder; }   private static string CreateTypeName<TBase>() where TBase : class {     return string.Format("{0}_RapidDynamicBaseProxy", typeof(TBase).Name); } As you can see, I’ve create a new public class derived from TBase which also implements my IProxy interface, this is used later for adding interceptors. If the base type is generic, the following GenericsHelper.MakeGenericType method is called. GenericsHelper using System; using System.Reflection.Emit; namespace Rapid.DynamicProxy.Types.Helpers {     /// <summary>     /// Helper class for generic types and methods.     /// </summary>     internal static class GenericsHelper     {         /// <summary>         /// Makes the typeBuilder a generic.         /// </summary>         /// <param name="concrete">The concrete.</param>         /// <param name="typeBuilder">The type builder.</param>         public static void MakeGenericType(Type baseType, TypeBuilder typeBuilder)         {             Type[] genericArguments = baseType.GetGenericArguments();               string[] genericArgumentNames = GetArgumentNames(genericArguments);               GenericTypeParameterBuilder[] genericTypeParameterBuilder                 = typeBuilder.DefineGenericParameters(genericArgumentNames);               typeBuilder.MakeGenericType(genericTypeParameterBuilder);         }           /// <summary>         /// Gets the argument names from an array of generic argument types.         /// </summary>         /// <param name="genericArguments">The generic arguments.</param>         public static string[] GetArgumentNames(Type[] genericArguments)         {             string[] genericArgumentNames = new string[genericArguments.Length];               for (int i = 0; i < genericArguments.Length; i++)             {                 genericArgumentNames[i] = genericArguments[i].Name;             }               return genericArgumentNames;         }     } }       As you can see, I’m getting all of the generic argument types and names, creating a GenericTypeParameterBuilder and then using the typeBuilder to make the new type generic. InterceptorsField The interceptors field will store a List<IInterceptor<TBase>>. Fields are simple made using the FieldBuilder class. The following code demonstrates how to create the interceptor field. FieldBuilder interceptorsField = typeBuilder.DefineField(     "interceptors",     typeof(System.Collections.Generic.List<>).MakeGenericType(typeof(IInterceptor<TBase>)),       FieldAttributes.Private     ); The field will now exist with the new Type although it currently has no data – we’ll deal with this in the constructor. Add method for interceptorsField To enable us to add to the interceptorsField list, we are going to utilise the Add method that already exists within the System.Collections.Generic.List class. We still however have to create the methodInfo necessary to call the add method. This can be done similar to the following: Add Interceptor Field MethodInfo addInterceptor = typeof(List<>)     .MakeGenericType(new Type[] { typeof(IInterceptor<>).MakeGenericType(typeof(TBase)) })     .GetMethod     (        "Add",        BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic,        null,        new Type[] { typeof(IInterceptor<>).MakeGenericType(typeof(TBase)) },        null     ); So we’ve create a List<IInterceptor<TBase>> type, then using the type created a method info called Add which accepts an IInterceptor<TBase>. Now in our constructor we can use this to call this.interceptors.Add(// interceptor); Building the Constructors This will be the first hard-core part of the proxy building process so I’m going to show the class and then try to explain what everything is doing. For a clear view, download the source from http://rapidioc.codeplex.com/, go to the test project and debug through the constructor building section. Anyway, here it is: DynamicConstructorBuilder using System; using System.Collections.Generic; using System.Reflection; using System.Reflection.Emit; using Rapid.DynamicProxy.Interception; using Rapid.DynamicProxy.Types.Helpers; namespace Rapid.DynamicProxy.Types.Constructors {     /// <summary>     /// Class for creating the proxy constructors.     /// </summary>     internal static class DynamicConstructorBuilder     {         /// <summary>         /// Builds the constructors.         /// </summary>         /// <typeparam name="TBase">The base type.</typeparam>         /// <param name="typeBuilder">The type builder.</param>         /// <param name="interceptorsField">The interceptors field.</param>         public static void BuildConstructors<TBase>             (                 TypeBuilder typeBuilder,                 FieldBuilder interceptorsField,                 MethodInfo addInterceptor             )             where TBase : class         {             ConstructorInfo interceptorsFieldConstructor = CreateInterceptorsFieldConstructor<TBase>();               ConstructorInfo defaultInterceptorConstructor = CreateDefaultInterceptorConstructor<TBase>();               ConstructorInfo[] constructors = typeof(TBase).GetConstructors();               foreach (ConstructorInfo constructorInfo in constructors)             {                 CreateConstructor<TBase>                     (                         typeBuilder,                         interceptorsField,                         interceptorsFieldConstructor,                         defaultInterceptorConstructor,                         addInterceptor,                         constructorInfo                     );             }         }           #region Private Methods           private static void CreateConstructor<TBase>             (                 TypeBuilder typeBuilder,                 FieldBuilder interceptorsField,                 ConstructorInfo interceptorsFieldConstructor,                 ConstructorInfo defaultInterceptorConstructor,                 MethodInfo AddDefaultInterceptor,                 ConstructorInfo constructorInfo             ) where TBase : class         {             Type[] parameterTypes = GetParameterTypes(constructorInfo);               ConstructorBuilder constructorBuilder = CreateConstructorBuilder(typeBuilder, parameterTypes);               ILGenerator cIL = constructorBuilder.GetILGenerator();               LocalBuilder defaultInterceptorMethodVariable =                 cIL.DeclareLocal(typeof(DefaultInterceptor<>).MakeGenericType(typeof(TBase)));               ConstructInterceptorsField(interceptorsField, interceptorsFieldConstructor, cIL);               ConstructDefaultInterceptor(defaultInterceptorConstructor, cIL, defaultInterceptorMethodVariable);               AddDefaultInterceptorToInterceptorsList                 (                     interceptorsField,                     AddDefaultInterceptor,                     cIL,                     defaultInterceptorMethodVariable                 );               CreateConstructor(constructorInfo, parameterTypes, cIL);         }           private static void CreateConstructor(ConstructorInfo constructorInfo, Type[] parameterTypes, ILGenerator cIL)         {             cIL.Emit(OpCodes.Ldarg_0);               if (parameterTypes.Length > 0)             {                 LoadParameterTypes(parameterTypes, cIL);             }               cIL.Emit(OpCodes.Call, constructorInfo);             cIL.Emit(OpCodes.Ret);         }           private static void LoadParameterTypes(Type[] parameterTypes, ILGenerator cIL)         {             for (int i = 1; i <= parameterTypes.Length; i++)             {                 cIL.Emit(OpCodes.Ldarg_S, i);             }         }           private static void AddDefaultInterceptorToInterceptorsList             (                 FieldBuilder interceptorsField,                 MethodInfo AddDefaultInterceptor,                 ILGenerator cIL,                 LocalBuilder defaultInterceptorMethodVariable             )         {             cIL.Emit(OpCodes.Ldarg_0);             cIL.Emit(OpCodes.Ldfld, interceptorsField);             cIL.Emit(OpCodes.Ldloc, defaultInterceptorMethodVariable);             cIL.Emit(OpCodes.Callvirt, AddDefaultInterceptor);         }           private static void ConstructDefaultInterceptor             (                 ConstructorInfo defaultInterceptorConstructor,                 ILGenerator cIL,                 LocalBuilder defaultInterceptorMethodVariable             )         {             cIL.Emit(OpCodes.Newobj, defaultInterceptorConstructor);             cIL.Emit(OpCodes.Stloc, defaultInterceptorMethodVariable);         }           private static void ConstructInterceptorsField             (                 FieldBuilder interceptorsField,                 ConstructorInfo interceptorsFieldConstructor,                 ILGenerator cIL             )         {             cIL.Emit(OpCodes.Ldarg_0);             cIL.Emit(OpCodes.Newobj, interceptorsFieldConstructor);             cIL.Emit(OpCodes.Stfld, interceptorsField);         }           private static ConstructorBuilder CreateConstructorBuilder(TypeBuilder typeBuilder, Type[] parameterTypes)         {             return typeBuilder.DefineConstructor                 (                     MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.RTSpecialName                     | MethodAttributes.HideBySig, CallingConventions.Standard, parameterTypes                 );         }           private static Type[] GetParameterTypes(ConstructorInfo constructorInfo)         {             ParameterInfo[] parameterInfoArray = constructorInfo.GetParameters();               Type[] parameterTypes = new Type[parameterInfoArray.Length];               for (int p = 0; p < parameterInfoArray.Length; p++)             {                 parameterTypes[p] = parameterInfoArray[p].ParameterType;             }               return parameterTypes;         }           private static ConstructorInfo CreateInterceptorsFieldConstructor<TBase>() where TBase : class         {             return ConstructorHelper.CreateGenericConstructorInfo                 (                     typeof(List<>),                     new Type[] { typeof(IInterceptor<TBase>) },                     BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic                 );         }           private static ConstructorInfo CreateDefaultInterceptorConstructor<TBase>() where TBase : class         {             return ConstructorHelper.CreateGenericConstructorInfo                 (                     typeof(DefaultInterceptor<>),                     new Type[] { typeof(TBase) },                     BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic                 );         }           #endregion     } } So, the first two tasks within the class should be fairly clear, we are creating a ConstructorInfo for the interceptorField list and a ConstructorInfo for the DefaultConstructor, this is for instantiating them in each contructor. We then using Reflection get an array of all of the constructors in the base class, we then loop through the array and create a corresponding proxy contructor. Hopefully, the code is fairly easy to follow other than some new types and the dreaded Opcodes. ConstructorBuilder This class defines a new constructor on the type. ILGenerator The ILGenerator allows the use of Reflection.Emit to create the method body. LocalBuilder The local builder allows the storage of data in local variables within a method, in this case it’s the constructed DefaultInterceptor. Constructing the interceptors field The first bit of IL you’ll come across as you follow through the code is the following private method used for constructing the field list of interceptors. private static void ConstructInterceptorsField             (                 FieldBuilder interceptorsField,                 ConstructorInfo interceptorsFieldConstructor,                 ILGenerator cIL             )         {             cIL.Emit(OpCodes.Ldarg_0);             cIL.Emit(OpCodes.Newobj, interceptorsFieldConstructor);             cIL.Emit(OpCodes.Stfld, interceptorsField);         } The first thing to know about generating code using IL is that you are using a stack, if you want to use something, you need to push it up the stack etc. etc. OpCodes.ldArg_0 This opcode is a really interesting one, basically each method has a hidden first argument of the containing class instance (apart from static classes), constructors are no different. This is the reason you can use syntax like this.myField. So back to the method, as we want to instantiate the List in the interceptorsField, first we need to load the class instance onto the stack, we then load the new object (new List<TBase>) and finally we store it in the interceptorsField. Hopefully, that should follow easily enough in the method. In each constructor you would now have this.interceptors = new List<User<int, IRepository>>(); Constructing and storing the DefaultInterceptor The next bit of code we need to create is the constructed DefaultInterceptor. Firstly, we create a local builder to store the constructed type. Create a local builder LocalBuilder defaultInterceptorMethodVariable =     cIL.DeclareLocal(typeof(DefaultInterceptor<>).MakeGenericType(typeof(TBase))); Once our local builder is ready, we then need to construct the DefaultInterceptor<TBase> and store it in the variable. Connstruct DefaultInterceptor private static void ConstructDefaultInterceptor     (         ConstructorInfo defaultInterceptorConstructor,         ILGenerator cIL,         LocalBuilder defaultInterceptorMethodVariable     ) {     cIL.Emit(OpCodes.Newobj, defaultInterceptorConstructor);     cIL.Emit(OpCodes.Stloc, defaultInterceptorMethodVariable); } As you can see, using the ConstructorInfo named defaultInterceptorConstructor, we load the new object onto the stack. Then using the store local opcode (OpCodes.Stloc), we store the new object in the local builder named defaultInterceptorMethodVariable. Add the constructed DefaultInterceptor to the interceptors field collection Using the add method created earlier in this post, we are going to add the new DefaultInterceptor object to the interceptors field collection. Add Default Interceptor private static void AddDefaultInterceptorToInterceptorsList     (         FieldBuilder interceptorsField,         MethodInfo AddDefaultInterceptor,         ILGenerator cIL,         LocalBuilder defaultInterceptorMethodVariable     ) {     cIL.Emit(OpCodes.Ldarg_0);     cIL.Emit(OpCodes.Ldfld, interceptorsField);     cIL.Emit(OpCodes.Ldloc, defaultInterceptorMethodVariable);     cIL.Emit(OpCodes.Callvirt, AddDefaultInterceptor); } So, here’s whats going on. The class instance is first loaded onto the stack using the load argument at index 0 opcode (OpCodes.Ldarg_0) (remember the first arg is the hidden class instance). The interceptorsField is then loaded onto the stack using the load field opcode (OpCodes.Ldfld). We then load the DefaultInterceptor object we stored locally using the load local opcode (OpCodes.Ldloc). Then finally we call the AddDefaultInterceptor method using the call virtual opcode (Opcodes.Callvirt). Completing the constructor The last thing we need to do is complete the constructor. Complete the constructor private static void CreateConstructor(ConstructorInfo constructorInfo, Type[] parameterTypes, ILGenerator cIL)         {             cIL.Emit(OpCodes.Ldarg_0);               if (parameterTypes.Length > 0)             {                 LoadParameterTypes(parameterTypes, cIL);             }               cIL.Emit(OpCodes.Call, constructorInfo);             cIL.Emit(OpCodes.Ret);         }           private static void LoadParameterTypes(Type[] parameterTypes, ILGenerator cIL)         {             for (int i = 1; i <= parameterTypes.Length; i++)             {                 cIL.Emit(OpCodes.Ldarg_S, i);             }         } So, the first thing we do again is load the class instance using the load argument at index 0 opcode (OpCodes.Ldarg_0). We then load each parameter using OpCode.Ldarg_S, this opcode allows us to specify an index position for each argument. We then setup calling the base constructor using OpCodes.Call and the base constructors ConstructorInfo. Finally, all methods are required to return, even when they have a void return. As there are no values on the stack after the OpCodes.Call line, we can safely call the OpCode.Ret to give the constructor a void return. If there was a value, we would have to pop the value of the stack before calling return otherwise, the method would try and return a value. Conclusion This was a slightly hardcore post but hopefully it hasn’t been too hard to follow. The main thing is that a number of the really useful opcodes have been used and now the dynamic proxy is capable of being constructed. If you download the code and debug through the tests at http://rapidioc.codeplex.com/, you’ll be able to create proxies at this point, they cannon do anything in terms of interception but you can happily run the tests, call base methods and properties and also take a look at the created assembly in Reflector. Hope this is useful. The next post should be up soon, it will be covering creating the private methods for calling the base class methods and properties. Kind Regards, Sean.

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