Zamboch

Unit of work using lambdas

2012-03-07T01:39:00.000+01:00

Are you tired of writing into log file on every begin and end of the method ? Use AOP. Well, not yet ready for post-compiler magic or dynamic runtime proxies ? Let's try lambdas (again).

static void Main(string[] args)
{
    Scope<LoggingFrame>.Wrap(() =>
    {
        Console.WriteLine("Hello world");
    });
}

Would produce this console

2012-03-07 00:46:58,248 DEBUG - BEGIN Main
Hello world
2012-03-07 00:46:58,258 DEBUG - END   Main

How to implement that ?

[DebuggerStepThrough]
public class Scope<TAdvice> where TAdvice : IAdvice, new()
{
    public static void Wrap(Action body)
    {
        IAdvice advice = Activator.CreateInstance<TAdvice>();
        advice.OnEntry(body);
        try
        {
            body();
            advice.OnLeave(body);
        }
        catch (Exception ex)
        {
            advice.OnException(body, ex);
            throw;
        }
        finally
        {
            advice.OnFinally(body);
        }
    }
}

public interface IAdvice
{
    void OnEntry(Delegate body);
    void OnLeave(Delegate body);
    void OnException(Delegate body, Exception exception);
    void OnFinally(Delegate body);
}

Implementation of the LoggingFrame advice is trivial.

Note that you could get similar behavior with IDisposable and using keyword, but you would not be able to log pending exception.
You could also think about TransactionScope, which would call tx.Complete() automatically when no exception is thrown.
Further improvement is to use dependency injection to instantiate the advises.

Another use-case is to implement Unit of Work or session/call context, while using TSL to reach topmost frame. I used it for NHibernate Session and EF DbContext (unit of work) recently. Interesting related article here.

private void Main(string[] args)
{
    Scope<UnitOfWork>.Wrap(session =>
    {
        var people = session.Person
            .Where(person => person.FirstName == "Pavel")
            .ToList();

        NestedLogic(people);

        //DbContext.SaveChanges() will be called here
    });

}

private void NestedLogic(IList<Person> people)
{
    //this will lookup parent session in TSL and reuse it
    Scope<UnitOfWork>.Wrap(session =>
    {
        foreach (var person in people)
        {
            if (person.LastName == "Savara")
            {
                person.Coder = true;
            }
            else
            {
                session.Person.Remove(person);
            }
        }
    });
}

Composition of scopes could be beautified.

Scope<LoggingFrame, TransactionFrame>.Wrap(() =>
{
    throw new Exception("rollback please");
});


[DebuggerStepThrough]
public class Scope<TOuterAdvice, TInnerAdvice> 
  where TOuterAdvice : IAdvice, new() 
  where TInnerAdvice : IAdvice, new()
{
    public static void Wrap(Action body)
    {
        Scope<TOuterAdvice>.Wrap(()=> Scope<TInnerAdvice>.Wrap(body));
    }
}

All code in the article is simplified and real implementation is exercise for readers.

Enjoy :-)

Fluentator - generate fluent API for your structures

2011-12-31T14:46:00.000+01:00

When working with nested structures like configuration or XML it is bit of pain with syntax in C#. Consider this code below. The object initializes in C# 3.0 helped a lot, but it's still pretty far from ideal. Important point here is readability, which is achieved thru nesting the initializers.

var model = new Model();
var pavel = new Employee("Pavel");
model.Companies.Add(new Company("Boldbrick & co.")
{
    Departments = new List<Department>
    {
        new Department("Software & Visions", "swv")
        {
            Teams = new List<Team>
            {
                new Team("Visions")
                {
                    Employees = new List<Employee>
                    {
                        // I was forced to move 
                        // pavel variable declaration completely out of scope
                        pavel,
                        new Employee("Ondra"),
                    },
                    IsAwesome = true,
                },
                new Team("Developers")
                {
                    Employees = new List<Employee>
                    (
                        // I can't do any statements or declarations here
                        // to prepare my data in-place
                        devNames.Select(n=>new Employee(n))
                    )
                    {
                        // note I can't add pavel first
                        pavel,
                    }
                }
            }
        }
    }
});

But there are downsides with approach above. You can't easily add same instance into 2 nodes. It forces you to declare pavel variable completely out of scope. And you can't use statements to prepare your data in place either. Note how Pavel is inserted after other employees into Developers team. The LINQ Select() helped great deal here, but it's not always possible to use it. With more complex model and bigger tree to build, this will become unmanageable mess.

So, extension methods and lambdas to rescue. Do you like code below better ? I certainly do. I can use statements and variable declarations in inner scope. I get more dense and readable code.

var model = new Model();
model.AddCompany("Boldbrick & co.", bb =>
{
    bb.AddDepartment("Software & Visions", "swv", swv =>
    {
        // variable is still bit out of scope, but not in the root scope
        var pavel = new Employee("Pavel");
        swv.AddTeam("Visions", visions =>
        {
            visions.AddEmployee(pavel);
            visions.AddEmployee("Ondra");
            visions.IsAwesome = true;
        });
        swv.AddTeam("Developers", devs => 
        {
            devs.AddEmployee(pavel);
            // I can add more employees after Pavel
            devs.AddEmployees(devNames.Select(n => new Employee(n)), dev=>
            {
                dev.Age = 33;
            });
            // and also can use any complex statement in-place
            for (int i = 0; i < devNames.Count; i++)
            {
                int ix=i;
                devs.AddEmployee(devNames[i], dev =>
                {
                    dev.Age = ix;
                });
            }
        });
    });
);});

How the extension method looks like ?

Below is extension method over external structure Department, which accepts same parameters as Team constructor. Inside is instance creations and adding to the collection. Finally to allow the nesting of scopes, we pass the new instance to Action<> delegate.

static public Team AddTeam(this Department self, string name, Action<Team> result = null)
{
    var item = new Team(name);
    self.Teams.Add(item);
    if (result != null) result(item);
    return item;
}

Generate the extensions

The extension method above is nice and useful but it's quite boring to write it for each combination of container and child item. Multiplied by all constructor signatures. So I decided to create ReflectionFluentator which can generate the code for you. It reads your model via reflection and generates the C# extensions. See sample how to use the generator.

And the same thing for XML ? Sure. You provide the XSD to XsdFluentator. See sample how to use the generator.

var doc=new XDocument();
doc.AddLibrary("Prague",prague =>
{
    prague.AddBook("Saturnin", book =>
    {
        book.AddAuthor("Zdenek Jirotka");
    });
    prague.AddBook("Bylo Nas 5", book =>
    {
        book.AddAuthor("Karel Polacek");
    });
});

This code can generate this XML as expected.

<library id="Prague"
  xmlns="http://polyglottos.googlecode.com/svn/trunk/demomodel/library.xsd">
  <book name="Saturnin">
    <author name="Zdenek Jirotka" />
  </book>
  <book name="Bylo Nas 5">
    <author name="Karel Polacek" />
  </book>
</library>

Note that both generators are more prototypes than ready to ship. They don't handle any edge scenarios when reading the metadata or writing the code. Fluentator is part of Polyglottos project. If you like the idea and wish to contribute improvements, please talk back.

At this point some of you may wonder what else could be made fluent this way. In my case, I realized that I need to generate the code and the code is just nested structure. So I created CodeDom code generator Polyglottos with fluent API. That's for another article next year. Enjoy the party tonight!

jni4net 0.8.6 - release

2011-09-19T23:08:00.006+02:00

Changes

fixed permission demand for sandboxed environments
improved proxygen can't find class reporting
improved the way we are looking for jni4net.j-xxx-.jar (while installed in GAC)
[#27] - fixed build script problems

Download here

Road map

May people asked for road map. This is my vision, not a promise.

jni4net 0.8.5 - release

2011-08-17T20:12:00.002+02:00

Changes

[# 9] - support for indexer properties [by Johannes Rudolph]
[#22] - Potential field name clash due to increasing numbering strategy of field names
[#24] - Change of current directory during init may disrupt other code running in parallel
[#25] - DirectByteBuffer doesn't work with Java 7

Download here

Host your own Roborumble server

2011-07-18T11:07:00.032+02:00

There are several reasons why you might want to run your own Roborumble server. Maybe you would like to run small local contest at your school or workplace. Or maybe you are testing your new shiny robot. Or may you want to collect some battle data, like myself.

The current Roborumble server is created and maintained by Darkcanuck. Luckily he shares the RumbleServer sources via subversion. It is implemented in PHP and MySQL.

Because I'm not PHP+MySQL expert, easiest solution for me was to download ready-made LAMP virtual machine and configure it.
I know you are busy ;-), so I published my virtual appliance, you could just start using it. You can download it and run it in VMWare Player. Password is robocode, you should change it as soon. Or you could follow the guide below.

Configure server

Once you have LAMP stack up and running you need few things:
Install subversion client
Get PHP sources
Configure RumbleServer
Turn on URL rewriting mod in Apache
Configure MySQL database and grant permissions

The appliance has could be configured from web admin. You can access it on https://192.168.1.12/ where 192.168.1.12 is the IP address assigned to the virtual machine by your DHCP server. I will use 192.168.1.12 which was assigned to me in rest of the article.

Webmin->Global configuration
  ->Configure Apache Modules->rewrite: switch ON

MyPhpAdmin
  Create database->roborumble   Import script schema/schema.sql
  Priviledges->add new user->
    name->rumbleuser
    pass->rumblepass
    Database for user->None
    Global privileges->Select+Update+Insert+Delete

On root shell do something like this

apt-get install subversion
cd /var/www/
mkdir rumble
cd rumble
svn co http://darkcanuck.net/svn/rumbleserver/trunk/ .
chmod g+w templates_c/
chown :www-data templates_c/
cat > participants.txt
[paste participants.txt file and press Ctrl-D]
cd config
cp config.php-sample config.php

Participants

Are defined as list of robots and their .jar files. Big competition is driven by this file. We could simplify our own list like this. We host the file on the appliance in folder /var/www/. So create you own shortlist and update it there. Note there are starting and ending tags.

----
<pre>
jk.mega.DrussGT 2.0.4,http://www.minifly.rchomepage.com/robocode/jk.mega.DrussGT_2.0.4.jar
voidious.Diamond 1.5.34b,http://www.dijitari.com/void/robocode/voidious.Diamond_1.5.34b.jar
</pre>
----

Configure client

Download and install Robocode 1.7.3
Edit c:\robocode\roborumble\roborumble.txt

  PARTICIPANTSURL=http://192.168.1.12/participants.txt
  UPDATEBOTSURL=http://192.168.1.12/rumble/RemoveOldParticipant
  RESULTSURL=http://192.168.1.12/rumble/UploadedResults
  RATINGS.URL=http://192.168.1.12/rumble/RatingsFile
  ITERATE=YES

start c:\robocode\roborumble.bat

Purge data

If you need to purge the data from the roborumble database and start from scratch just delete rows using MyPhpAdmin.

delete from battle_results;
delete from game_pairings;
delete from bot_data;
delete from participants;
delete from upload_stats;
delete from upload_users;

Oh, and once you are done with your local competition, don't forget to redirect back to official RoboRumble server and contribute your CPU power!

Download turnkey-roborumble.2011-07-18.zip.torrent

HowTo: Pass build property from TeamCity into Freemaker email notification template

2011-07-07T21:08:00.011+02:00

There is no magic, once you know it. My use-case was to prefix build number with configurable text before sending an email. The text was represented as TeamCity property system.tc.branch.number in my case.

TeamCity email templates are implemented with Freemaker. The TeamCity exposes all build properties as hash table on SBuild.getBuildOwnParameters().

In the template the instance of SBuild is accessible under build variable. Freemaker allows calling bean properties, in our case it would be build.buildOwnParameters, map lookup thru square-bracket syntax [] and literals are enclosed in apostrophes.

#${build.buildOwnParameters['system.tc.branch.number']}.${build.buildNumber}

jni4net 0.8.4 - release

2011-06-28T21:48:00.008+02:00

Changes

Added ability to load proxies into specified classLoader by Jose Chillan.
Bridge.LoadAndRegisterAssemblyFromClassLoader(File, ClassLoader)
JNIEnv.DetachCurrentThread() contributed by Renier B.
Bridge.setClrVersion() made static by Leonid Bogdanov

Download here

Raising Property Changed fast and safe - yet another solution

2011-03-26T15:03:00.024+01:00

This Thursday we discussed with my colleagues how to raise property changed event. We learned that it could be done
a) via string literal,
b) via lambda expression tree,
c) via StackTrace or MethodBase.GetCurrentMethod().
Nice summary is here. or here

We did some naive performance test and learned that for 500k iterations on simple property, there is big difference in speed.
a) is really fast, 13ms
b) is slow, 1417ms, I guess because security checks apply for every call and every stack frame, and can't be fired from other properties.
c) is slow, 2518ms, very slow, because expression tree is constructed for every call

So we played with it for a while and I invented solution with anonymous type (at botom).

Update 27.3.2011: I was so focused on speed that I didn't realized that the solution yesterday didn't work nicely for rename. What a shame. I hope people give me another chance today. Here we have postponed creation of the expression tree, it takes about 75ms. And this time my ReSharper renames it correctly :-)
Update 5.12.2011: As Alex noted in comments, there was thread safety issue with Dictionary. The code is now fixed with Hashtable instead.

public abstract class ModelBase : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    private static readonly Hashtable Names = new Hashtable();

    protected void RaisePropertyChange(Func<string> key)
    {
        if (PropertyChanged != null)
        {
            var propertyName = (PropertyChangedEventArgs)Names[key];
            if (propertyName==null)
            {
                propertyName = new PropertyChangedEventArgs(key());
                lock (Names)
                {
                    Names[key] = propertyName;
                }
            }
            PropertyChanged(this, propertyName);
        }
    }

    protected static string Reg<T>(Expression<Func<T>> property)
    {
        return (property.Body as MemberExpression).Member.Name;
    }
}

public class Model : ModelBase
{
    private string firstName2;
    public string FirstName2
    {
        get { return firstName2; }
        set
        {
            firstName2 = value;
            RaisePropertyChange(() => Reg(() => FirstName2));
        }
    }
}

Doesn't work: The lambda just helps to define the type without creating the instance and calling the getter. It takes about 77ms for half million calls.

public abstract class ModelBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        private static readonly Dictionary<Type, PropertyChangedEventArgs> Names = 
          new Dictionary<Type, PropertyChangedEventArgs>();

        protected void RaisePropertyChange<T>(Func<T> f)
        {
            if (PropertyChanged!=null)
            {
                var key = typeof(T);
                PropertyChangedEventArgs evntArgs;
                if (!Names.TryGetValue(key, out evntArgs))
                {
                    var propertyName = key.GetProperties()[0].Name;
                    evntArgs = new PropertyChangedEventArgs(propertyName);
                    lock(Names)
                    {
                        Names[key] = evntArgs;
                    }
                }
                PropertyChanged(this, evntArgs);
            }
        }
    }

    public class Model : ModelBase
    {
        private string firstName;
        public string FirstName
        {
            get { return firstName; }
            set {
                if (firstName != value)
                {
                    firstName = value;
                    RaisePropertyChange(() => new {FirstName});
                }
            }
        }
    }

jni4net 0.8.3 - release

2011-02-20T13:15:00.005+01:00

Changes

added support for IBM JRE
added drools sample
added BridgeSetup.IgnoreJavaHome
improved error logging during initialization

Blocked DLLs for CLR 4.0

If you download the distribution package on jni4net and unzip it via Windows Explorer, it will set the DLL security zone as untrusted. That will prevent CLR 4.0 from loading the DLL and you will receive exception while initializing jni4net from Java side.
The message states:

Can't init BridgeExport:An attempt was made to load an assembly from a network l
ocation which would have caused the assembly to be sandboxed in previous version
s of the .NET Framework. This release of the .NET Framework does not enable CAS
policy by default, so this load may be dangerous. If this load is not intended t
o sandbox the assembly, please enable the loadFromRemoteSources switch. See http
://go.microsoft.com/fwlink/?LinkId=155569 for more information.

You can solve it by unblocking the DLLs.
Right-click on the files, open file properties and click unblock button.

jni4net 0.8.2 - bugfix release

2011-01-02T13:15:00.001+01:00

Bug fixes

upgraded nMaven, NUnit, made build 32bit only
fixed throwing exceptions for missing proxy classes
[#18] - C# string[]{null} -> JVM -> null reference exception
improved architecture detection

jni4net 0.8.1 - bugfix release

2010-11-07T18:15:00.005+01:00

Fixed memory leak reported by Jaco Ackermann
Included improved CLR detection contributed by Leonid Bogdanov

Download 0.8.1 here

Decomposition in functional languages

2010-09-23T00:15:00.006+02:00

Got an idea: functions (in FP) could be composed similar was as components in OOP. For example with dependency injection. For components in OOP we use interfaces. For functions we could use delegates. To achieve decomposition and modularity.
I tried to find something about it. No luck. Probably because there are no functional programs big enough to need this ?
While searching for enterprise scale applications written in FP I found this list. Functional Programming in the Real World and this paper

I hope I just missed the killer application for FP, which would be big enough to deserve decomposition. Maybe someone could find me answer at stack overflow.

CLR 4.0 for Robocode

2010-07-20T22:25:00.010+02:00

I finally got motivated by Justin and Jason to do something for Robocode .NET again. I upgraded it to jni4net 0.8. This means Robocode will prefer CLR 4.0 if installed and then will run robots written in C# 4.0 or F#. I also implemented Robocode Control API for .NET. I piggyback to Flemming's working branch, hope he will not kill me once he returns from holidays :-D

Download preview is there, Alpha quality.
robocode-1.7.2.2-Alpha-setup.jar
robocode.dotnet-1.7.2.2-Alpha-setup.jar

MyFirstRobot.F#

I really like the syntax.

namespace SampleFs
open Robocode
type MyFirstRobot() = 
    inherit Robot()
    override robot.Run() = 
            while true do
                robot.TurnLeft(40.0)
                robot.Ahead(20.0)
    override robot.OnScannedRobot(evnt : ScannedRobotEvent) = 
            robot.Fire(1.0)
    override robot.OnHitByBullet(evnt : HitByBulletEvent) = 
            robot.TurnLeft(90.0 - evnt.Bearing)

Learning F# with Project Euler - day 2

2010-05-30T16:27:00.003+02:00

Problem 4

open Microsoft.FSharp.Core.Operators
let findpalindrome xs ys =
    let separate s p = (s % (pown 10 (p+1))) - (s % (pown 10 p))
    let shiftl s p o = (separate s p) / (pown 10 (p-o))
    let shiftr s p o = (separate s p) * (pown 10 (o-p))
    let flip f = shiftl f 5 0 + shiftl f 4 1 + shiftl f 3 2 + shiftr f 2 3 + shiftr f 1 4 + shiftr f 0 5
    let findi xs y = xs |> Seq.filter( fun x -> (((x*y) = flip (x*y)) && (separate (x*y) 0 <> 0) ) ) |> Seq.map(fun x -> (x*y,x))
    ys |> Seq.collect(fun y -> (findi xs y)) |> Seq.maxBy(fun t -> fst(t))

findpalindrome [100..999][100..999]

Problem 5

let test = 
    let max = (primes 20 |> Seq.reduce(fun a c -> a*c))*8L*3L
    [1L..20L] |> Seq.filter(fun x -> (max % x) <> 0L)

Problem 6

let diff xs = 
    let sumsq = xs |> Seq.reduce(fun c a -> (a*a)+c)
    let sum = (xs |> Seq.reduce(fun c a -> (a+c)))
    let sqsum  = sum*sum
    sqsum  - sumsq

diff [1..100]

Problem 7

open Microsoft.FSharp.Core.Operators
let primesnth nthprime = 
    let maxPrime = 300000
    let pr : bool array = Array.zeroCreate maxPrime
    let mutable res = 0
    let mutable nth = 0
    let mutable cur=2
    while (nth < nthprime) do
        if not pr.[cur] then
            for wr in cur+cur .. cur .. maxPrime-1 do pr.[wr] <- true
            res <- cur
            nth <- nth + 1 
        cur <- cur + 1
    res

primesnth 10001

Learning F# with projecteuler.net

2010-05-28T01:49:00.006+02:00

Wow, lot of fun with projecteuler.net !

Problem 1

[1..999] |> Seq.filter( fun x -> (x % 3 = 0 || x % 5 = 0)) |> Seq.sum

Problem 2

let fib max = 
    let rec fibo a b max = 
        if b>= max then a :: [] else a :: fibo b (a+b) max
    fibo 1 2 max

fib 4000000 |> Seq.filter(fun x -> (x % 2 = 0)) |> Seq.toList|> Seq.sum

Problem 3

open Microsoft.FSharp.Math 
open System.Collections.Generic
let maxPrime:int= (int) (System.Math.Sqrt((float)600851475143I))
let primes maxPrime = 
    let pr : bool array = Array.zeroCreate maxPrime
    let res = new List()
    for cur in 2 .. maxPrime/2 do
        if not pr.[cur] then for wr in cur+cur .. cur .. maxPrime-1 do pr.[wr] <- true
    for cur in 1 .. maxPrime-1 do
        if not pr.[cur] then res.Add(new bigint(cur))
    res

primes maxPrime |> 
    Seq.filter(fun x -> ((600851475143I % x) = 0I )) 
    |> Seq.map( fun x -> ((int)(x))) 
    |> Seq.max

jni4net NOT yet on Mono & Linux

2010-04-17T22:24:00.005+02:00

I started with investigations of support for Mono on x86. The key problem is different calling convention - cdecl. My current implementation of JniLocalHandle is build on top of assumption that small structures are put onto stack same way as scalar types. But that's not valid assumption, it works just for stdcall. cdecl allocates the structure on heap and passes just pointer to the structure, no matter how big the structure is. Why I created JniLocalHandle ? Because I wanted to make strongly typed difference between JniLocalHandle and JniGlobalHandle. We could drop it and use IntPtr in order to deal with this problem. It will impact all generated proxies on C# side.
There is another problem with cdecl, because I need to put

[UnmanagedFunctionPointer(CallingConvention.xxx)]

on any JNI delegate. Example is JNIEnv.AllocObject. I think I'll need to duplicate whole JNIEnv class in order to avoid condition for each call.
Last small problem is with JNI.Dll which has the main

[DllImport("jvm.dll", CallingConvention = CallingConvention.StdCall)]

, it must be duplicated as well, because there is jvm.so on Linux.

Currently I don't hear from people that they need Mono/Linux support for jni4net. If you think you need it, please tell us the use case. I'm interested to hear why Mono support is worth of the effort. Till then I put it on ice.

jni4net version 0.8 for .NET 4.0

2010-04-17T21:55:00.006+02:00

added support for CLR v 4.0
v40 is now loaded by default if it could be found. You could set the version explicitly with Bridge.setClrVersion()
#8 added BridgeSetup.AddJVMOption(string)

Download jni4net 0.8

jni4net 0.7.1 - small bugfix release

2010-03-03T03:58:00.002+01:00

Bug fixes

[#7] - added ParPrimC2J(IntPtr)
[#5] - Reading Java home location from the Windows registry (Contributed by Martin Matula), BridgeSetup extended with JavaHome, and improved JavaHome auto detection
fixed missing assembly version for jni4net.n.*.dll

Robocode with C++/CLI

2010-02-25T22:55:00.002+01:00

Recently I spotted question if it's possible to create robot in C++. Here is the answer. Ok, I know, it's not like real C++ with pointers etc, this is managed version of C++, which is safe enough to be runnable in Robocode.

Download VS 2008 Express C++
Create new CLR-> Class Library (DLL) project
Go to project properties, Common Properties, Add New Reference, and add robocode.dll from lib folder of your robocode installation.
Go to project properties, Configuration properties, General, Common Language Runtime support and set it to Safe MSIL (/clrsafe)
Go to AssemblyInfo.cpp and delete line with [assembly:SecurityPermission(SecurityAction::RequestMinimum, UnmanagedCode = true)];
Go to [myCppRobot].h and insert code below
Compile it, drop the DLL into Robocode and enjoy!

#pragma once
using namespace System;
using namespace Robocode;
namespace myCppR {
    public ref class MyCplusplusRobot : Robot {
    public:
        virtual void Run() override {
            while(true) {
                Ahead(100);
                TurnLeft(100);
            }
        }
    };
}

Robocode .NET - 1.7.2 public beta

2010-02-15T23:49:00.002+01:00

This release of Robocode is big achievement for me.

jni4net version 0.7 released

2010-02-13T23:41:00.006+01:00

support for delegates and events

.NET events and delegates are supported by proxygen and runtime. From Java side they could be invoked with Invoke() method which has proper signature. Delegates could be also implemented on Java side, by usual anonymous class and passed back to CLR. So Java could subscribe to .NET events.

this.button1.addClick(new system.EventHandler(){
        public void Invoke(system.Object sender, system.EventArgs e){
            button1.setText("Clicked");
        }
    });

Full code is in winforms sample, which is part of binaries.

Other changes

solved problem with spaces in path to dll/jar
assembly loading now uses java.io.File or assembly name (breaking change)
static class is no longer found by name, attribute parameter added (breaking change)

Download there

jni4net version 0.6 released

2010-01-24T01:32:00.006+01:00

Implemented out and ref parameter from C#

DateTime.TryParse

Out<DateTime> dt=new Out<DateTime>();
if (DateTime.TryParse("2009-08-28",dt)){
    System.out.println(dt.getValue());
}

Improved proxygen to not generate virtual method overrides
Eliminated lot of warnings in generated code
Strongly typed JNI references (this is breaking change, please regenerate your proxies)
Sun specific DirectBufferCleaner, which holds the reference to pinned buffer
Native methods unregistration when appdomain unloads
Switched off signed .jar, because it prevents other people generating (unsigned) proxies into same packages. For example java.util_
Possibility to specify alternate classloader
Declarative security for running in partially trusted environments
JVM exceptions are serializable for CLR binary serialization

Download there

Robocode .NET - alpha bits

2010-01-09T16:30:00.009+01:00

I'm proud to present working version of .NET Robocode for community testing. It took me almost exactly 2 years.

Prerequisites

make sure you have .NET framework >= 2.0 installed on your windows box
backup your robocode home

Install and start

Download robocode-1.7.3.0-setup.jar and robocode.dotnet-1.7.3.0-setup.jar
run robocode-1.7.3.0-setup.jar
run robocode.dotnet-1.7.3.0-setup.jar
start robocode.bat
start new battle with samplecs.MyCsTeam and samplecs.PaintingRobot
open samplecs.PaintingRobot dialog and enable painting

Optional

start your Visual Studio
open robots/samplescs/samplescs.csproj
or create project new and reference robocode.dll from libs\ (Robot API for .NET)
and code your own .NET robot :-D

Please try it and say what you think !

Known gaps

Robot API xml documentation is not yet ready
IGraphics/onPaint have just simple operations implemented
Robot could create unlimited threads, (but could not cause any harm to your computer)
jni4net 0.6 was not released public yet
Few unit tests still fail

These binaries above are 1.7.3, but that was just working number. We will merge it to trunk and release as 1.7.2 probably. Sources are in trunk already.

Enjoy!

jni4net version 0.5 released

2009-12-04T00:56:00.008+01:00

Second public release of jni4net is out. New features are:

Simplified proxygen to wrap all classes in DLL or JAR file from command-line, without time spent on config file. It as well provides very simplistic build.cmd. I will write another article about proxygen soon, till then look at new samples.
Ported java.nio.ByteBuffer to .NET, so you could share same byte array in both VMs. You are able to use BinaryWriter in .NET as well, but same byte order and interface is more convenient.

There are new Adapt.Enumeration and Adapt.Disposable methods on CLR side. They are convenience adapters from corresponding Java interfaces.

foreach (var prop in Adapt.Enumeration(javaSystemProperties.keys()))
{
    cnt++;
}

using (var fis = Adapt.Disposable(new FileInputStream(classPath)))
{
    using (var zis = Adapt.Disposable(new ZipInputStream(fis.Real)))
    {
        ZipEntry entry = zis.Real.getNextEntry();
        while (entry!=null)
        {
            string name = entry.getName();
            entry = zis.Real.getNextEntry();
        }
    }
}

Improved proxygen code generator
Few minor bugfixes
New troubleshooter page

Download there

How calling from Java to .NET works in jni4net

2009-11-03T22:46:00.009+01:00

Tonight I would like to explain how calling from Java to .NET works with jni4net. The other way around is described in previous article, it would be good if you read that first if you didn't yet.

So, in JNI there is method which allow you to register native implementation of Java method. Such method had "native" keyword in it's signature. I believe that it's actually how low level methods in Java runtime are implemented.

We use proxygen tool, which is part of jni4net, to reflect any public members of .NET type and then to generate Java proxies. Those proxy methods are marked native. The generator must do few translations to follow Java naming rules. Namespaces are always lower-cased to become packages. Properties are converted to bean-like get and set methods.

For exceptions the situation is similar. system.Exception proxy is inherited from Java java.lang.RuntimeException to be throw-able. Therefore it isn't inherited from system.Object proxy. But there is system.IObject interface on both of them for your convenience.

The proxy implements Java finalizer, so when JVM GC cleans up the proxy instance, the real CLR instance is released as well. The reference to CLR is implemented as GCHandle converted to long and kept on JVM side inside the proxy.

system.Object proxy as well overrides toString() method and forwards it to CLR. It seems that in version 0.4 I forgot to override hashCode() and equals(), sorry about that ;-)

The implementation is is asymmetric to CLR->JVM proxies, because for both it's CLR which does the translation work. The wrapper have signature which is expected by JNI RegisterNatives. I apply Marshal.GetFunctionPointerForDelegate to wrapper methods to get endpoint callable by JVM. Side note is that JNI RegisterNatives does not make any difference between static and instance methods. They are identified by name and signature only, strange limitation.

Last trick I mention is about initial CLR bootstrap. During initial design I realized that there is way how to export native method from managed DLL. So I currently use that trick to create DLL with signature friendly to JVM. It seems to me now, that I will need to change my approach soon in order to support multiple versions of CLR and Mono on Linux. Probably I would need to use C++/COM. For now, we have 32bit and 64bit CLR 2.0 on Windows.

Next time maybe about interfaces and type casting.