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  • PostSharp, Obfuscation, and IL

    - by Simon Cooper
    Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day!

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  • Call methods in main method

    - by Niloo
    this is my main method that gets 3 integers from command line and I parse then in my validating method. However I have one operation method that calls 3 other methods, but i don't know what type of data and howmany I have to put in my operatinMethod() " cuase switch only gets one); AND also in my mainMethod() for calling the operationMehod(); itself? please let me know if i'm not clear? Thanx! main method: public class test { // Global Constants final static int MIN_NUMBER = 1; final static int MAX_PRIME = 10000; final static int MAX_FACTORIAL = 12; final static int MAX_LEAPYEAR = 4000; //Global Variables static int a,b,c; public static void main (String[] args) { for(int i =0; i< args.length; i++){} if(validateInput(args[0],args[1],args[2])){ performOperations(); } } //Validate User Input public static boolean validateInput(String num1,String num2,String num3){ boolean isValid = false; try{ try{ try{ a = Integer.parseInt(num1); if(!withinRange(a,MIN_NUMBER, MAX_PRIME)) { System.out.println("The entered value " + num1 +" is out of range [1 TO 10000]."); } isValid = true; } catch(Exception ex) { System.out.println("The entered value " + num1 + " is not a valid integer. Please try again."); } b = Integer.parseInt(num2); if(!withinRange(b,MIN_NUMBER, MAX_FACTORIAL)) { System.out.println("The entered value " + num2 +" is out of range [1 TO 12]."); } isValid = true; } catch(Exception ex) { System.out.println("The entered value " + num2 + " is not a valid integer. Please try again."); } c = Integer.parseInt(num3); if(!withinRange(c,MIN_NUMBER, MAX_LEAPYEAR)) { System.out.println("The entered value " + num3 +" is out of range [1 TO 4000]."); } isValid = true; } catch(Exception ex) { System.out.println("The entered value " + num3 + " is not a valid integer. Please try again."); } return isValid; } //Check the value within the specified range private static boolean withinRange(int userInput ,int min, int max){ boolean isInRange = true; if(userInput < min || userInput > max){ isInRange = false; } return isInRange; } //Perform operations private static void performOperations(int userInput) { switch(userInput) { case 1: // count Prime numbers countPrimes(a); break; case 2: // Calculate factorial getFactorial(b); break; case 3: // find Leap year isLeapYear(c); break; } } // Verify Prime Number private static boolean isPrime(int prime) { for(int i = 2; i <= Math.sqrt(prime) ; i++) { if ((prime % i) == 0) { return false; } } return true; } // Calculate Prime private static int countPrimes(int userInput){ int count =0; for(int i=userInput; i<=MAX_PRIME; i++) { if(isPrime(i)){ count++; } } System.out.println("Exactly "+ count + " prime numbers exist between "+ a + " and 10,000."); return count; } // Calculate the factorial value private static int getFactorial(int userInput){ int ans = userInput; if(userInput >1 ){ ans*= (getFactorial(userInput-1)); //System.out.println("The value of "+ b +"! is "+ getFactorial(userInput)); } return ans; } // Determine whether the integer represents a leap year private static boolean isLeapYear(int userInput){ if (userInput % 4 == 0 && userInput % 400 == 0 && userInput % 100 ==0){ System.out.println("The year "+ c +" is a leap year"); } else { System.out.println("The year "+ c +" is a not leap year"); } return false; } }

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  • Help to edit the Recent Posts Wordpress widget to diplay in all 3 languages at once

    - by CreativEliza
    Site link: http://nuestrafrontera.org/wordpress/ I want the feed of recent post titles to show in the sidebar for all 3 languages, separated by language. So, for example, under Recent Posts the sidebar would have "English" and then the latest 3 posts in English, then "Español" and the latest 3 in Spanish and then French. All in a list in the column and appearing on all pages with the sidebar in all languages. I am using the most current version of Wordpress with the WPML plugin. I believe the Wordpress widget for Recent Posts needs to be tweaked to do this. Here is the code (from wp-includes/default-widgets.php): class WP_Widget_Recent_Posts extends WP_Widget { function WP_Widget_Recent_Posts() { $widget_ops = array('classname' => 'widget_recent_entries', 'description' => __( "The most recent posts on your blog") ); $this->WP_Widget('recent-posts', __('Recent Posts'), $widget_ops); $this->alt_option_name = 'widget_recent_entries'; add_action( 'save_post', array(&$this, 'flush_widget_cache') ); add_action( 'deleted_post', array(&$this, 'flush_widget_cache') ); add_action( 'switch_theme', array(&$this, 'flush_widget_cache') ); } function widget($args, $instance) { $cache = wp_cache_get('widget_recent_posts', 'widget'); if ( !is_array($cache) ) $cache = array(); if ( isset($cache[$args['widget_id']]) ) { echo $cache[$args['widget_id']]; return; } ob_start(); extract($args); $title = apply_filters('widget_title', empty($instance['title']) ? __('Recent Posts') : $instance['title']); if ( !$number = (int) $instance['number'] ) $number = 10; else if ( $number < 1 ) $number = 1; else if ( $number > 15 ) $number = 15; $r = new WP_Query(array('showposts' => $number, 'nopaging' => 0, 'post_status' => 'publish', 'caller_get_posts' => 1)); if ($r->have_posts()) : ?> <?php echo $before_widget; ?> <?php if ( $title ) echo $before_title . $title . $after_title; ?> <ul> <?php while ($r->have_posts()) : $r->the_post(); ?> <li><a href="<?php the_permalink() ?>" title="<?php echo esc_attr(get_the_title() ? get_the_title() : get_the_ID()); ?>"><?php if ( get_the_title() ) the_title(); else the_ID(); ?> </a></li> <?php endwhile; ?> </ul> <?php echo $after_widget; ?> <?php wp_reset_query(); // Restore global post data stomped by the_post(). endif; $cache[$args['widget_id']] = ob_get_flush(); wp_cache_add('widget_recent_posts', $cache, 'widget'); } function update( $new_instance, $old_instance ) { $instance = $old_instance; $instance['title'] = strip_tags($new_instance['title']); $instance['number'] = (int) $new_instance['number']; $this->flush_widget_cache(); $alloptions = wp_cache_get( 'alloptions', 'options' ); if ( isset($alloptions['widget_recent_entries']) ) delete_option('widget_recent_entries'); return $instance; } function flush_widget_cache() { wp_cache_delete('widget_recent_posts', 'widget'); } function form( $instance ) { $title = esc_attr($instance['title']); if ( !$number = (int) $instance['number'] ) $number = 5; ?> <p><label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Title:'); ?></label> <input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo $title; ?>" /></p> <p><label for="<?php echo $this->get_field_id('number'); ?>"><?php _e('Number of posts to show:'); ?></label> <input id="<?php echo $this->get_field_id('number'); ?>" name="<?php echo $this->get_field_name('number'); ?>" type="text" value="<?php echo $number; ?>" size="3" /><br /> <small><?php _e('(at most 15)'); ?></small></p> <?php } }

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  • storing data in a database using edit text and button

    - by user1841444
    Hai im trying to Insert data into database using EditText and Button i have created. Im stuck at Activity part of the Code.I unbale to proceed how to write the Onclick action part for Button and EditText part Please help me. Im new to android DBAdapter.java package com.example.database1; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.util.Log; public class DBAdapter { public static final String KEY_ROWID = "_id"; public static final String KEY_ISBN = "isbn"; public static final String KEY_TITLE = "title"; public static final String KEY_PUBLISHER = "publisher"; private static final String TAG = "DBAdapter"; private static final String DATABASE_NAME = "books"; private static final String DATABASE_TABLE = "titles"; private static final int DATABASE_VERSION = 1; private static final String DATABASE_CREATE = "create table titles (_id integer primary key autoincrement, " + "isbn text not null, title text not null, " + "publisher text not null);"; private final Context context; private DatabaseHelper DBHelper; private SQLiteDatabase db; public DBAdapter(Context ctx) { this.context = ctx; DBHelper = new DatabaseHelper(context); } private static class DatabaseHelper extends SQLiteOpenHelper { DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL(DATABASE_CREATE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { Log.w(TAG, "Upgrading database from version " + oldVersion + " to " + newVersion + ", which will destroy all old data"); db.execSQL("DROP TABLE IF EXISTS titles"); onCreate(db); } } //---opens the database--- public DBAdapter open() throws SQLException { db = DBHelper.getWritableDatabase(); return this; } //---closes the database--- public void close() { DBHelper.close(); } //---insert a title into the database--- public long insertTitle(String isbn, String title, String publisher) { ContentValues initialValues = new ContentValues(); initialValues.put(KEY_ISBN, isbn); initialValues.put(KEY_TITLE, title); initialValues.put(KEY_PUBLISHER, publisher); return db.insert(DATABASE_TABLE, null, initialValues); } //---deletes a particular title--- public boolean deleteTitle(long rowId) { return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0; } //---retrieves all the titles--- public Cursor getAllTitles() { return db.query(DATABASE_TABLE, new String[] { KEY_ROWID, KEY_ISBN, KEY_TITLE, KEY_PUBLISHER}, null, null, null, null, null); } //---retrieves a particular title--- public Cursor getTitle(long rowId) throws SQLException { Cursor mCursor = db.query(true, DATABASE_TABLE, new String[] { KEY_ROWID, KEY_ISBN, KEY_TITLE, KEY_PUBLISHER }, KEY_ROWID + "=" + rowId, null, null, null, null, null); if (mCursor != null) { mCursor.moveToFirst(); } return mCursor; } //---updates a title--- public boolean updateTitle(long rowId, String isbn, String title, String publisher) { ContentValues args = new ContentValues(); args.put(KEY_ISBN, isbn); args.put(KEY_TITLE, title); args.put(KEY_PUBLISHER, publisher); return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0; } } DatabaseActivity.java package com.example.database1; import android.os.Bundle; import android.app.Activity; import android.database.Cursor; import android.view.Menu; import android.widget.Toast; public class DatabaseActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_database); DBAdapter db=new DBAdapter(this); db.open(); } } activity_database.xml: <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent"> <EditText android:id="@+id/edit1" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <EditText android:id="@+id/edit2" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <EditText android:id="@+id/edit3" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <Button android:id="@+id/submit" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </LinearLayout>

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  • Refactoring FizzBuzz

    - by MarkPearl
    A few years ago I blogger about FizzBuzz, at the time the post was prompted by Scott Hanselman who had podcasted about how surprized he was that some programmers could not even solve the FizzBuzz problem within a reasonable period of time during a job interview. At the time I thought I would give the problem a go in F# and sure enough the solution was fairly simple – I then also did a basic solution in C# but never posted it. Since then I have learned that being able to solve a problem and how you solve the problem are two totally different things. Today I decided to give the problem a retry and see if I had learnt anything new in the last year or so. Here is how my solution looked after refactoring… Solution 1 – Cheap and Nasty public class FizzBuzzCalculator { public string NumberFormat(int number) { var numDivisibleBy3 = (number % 3) == 0; var numDivisibleBy5 = (number % 5) == 0; if (numDivisibleBy3 && numDivisibleBy5) return String.Format("{0} FizzBuz", number); else if (numDivisibleBy3) return String.Format("{0} Fizz", number); else if (numDivisibleBy5) return String.Format("{0} Buz", number); return number.ToString(); } } class Program { static void Main(string[] args) { var fizzBuzz = new FizzBuzzCalculator(); for (int i = 0; i < 100; i++) { Console.WriteLine(fizzBuzz.NumberFormat(i)); } } } My first attempt I just looked at solving the problem – it works, and could be an acceptable solution but tonight I thought I would see how far  I could refactor it… The section I decided to focus on was the mass of if..else code in the NumberFormat method. Solution 2 – Replacing If…Else with a Dictionary public class FizzBuzzCalculator { private readonly Dictionary<Tuple<bool, bool>, string> _mappings; public FizzBuzzCalculator(Dictionary<Tuple<bool, bool>, string> mappings) { _mappings = mappings; } public string NumberFormat(int number) { var numDivisibleBy3 = (number % 3) == 0; var numDivisibleBy5 = (number % 5) == 0; var mappedKey = new Tuple<bool, bool>(numDivisibleBy3, numDivisibleBy5); return String.Format("{0} {1}", number, _mappings[mappedKey]); } } class Program { static void Main(string[] args) { var mappings = new Dictionary<Tuple<bool, bool>, string> { { new Tuple<bool, bool>(true, true), "- FizzBuzz"}, { new Tuple<bool, bool>(true, false), "- Fizz"}, { new Tuple<bool, bool>(false, true), "- Buzz"}, { new Tuple<bool, bool>(false, false), ""} }; var fizzBuzz = new FizzBuzzCalculator(mappings); for (int i = 0; i < 100; i++) { Console.WriteLine(fizzBuzz.NumberFormat(i)); } Console.ReadLine(); } } In my second attempt I looked at removing the if else in the NumberFormat method. A dictionary proved to be useful for this – I added a constructor to the class and injected the dictionary mapping. One could argue that this is totally overkill, but if I was going to use this code in a large system an approach like this makes it easy to put this data in a configuration file, which would up its OC (Open for extensibility, closed for modification principle). I could of course take the OC principle even further – the check for divisibility by 3 and 5 is tightly coupled to this class. If I wanted to make it 4 instead of 3, I would need to adjust this class. This introduces my third refactoring. Solution 3 – Introducing Delegates and Injecting them into the class public delegate bool FizzBuzzComparison(int number); public class FizzBuzzCalculator { private readonly Dictionary<Tuple<bool, bool>, string> _mappings; private readonly FizzBuzzComparison _comparison1; private readonly FizzBuzzComparison _comparison2; public FizzBuzzCalculator(Dictionary<Tuple<bool, bool>, string> mappings, FizzBuzzComparison comparison1, FizzBuzzComparison comparison2) { _mappings = mappings; _comparison1 = comparison1; _comparison2 = comparison2; } public string NumberFormat(int number) { var mappedKey = new Tuple<bool, bool>(_comparison1(number), _comparison2(number)); return String.Format("{0} {1}", number, _mappings[mappedKey]); } } class Program { private static bool DivisibleByNum(int number, int divisor) { return number % divisor == 0; } public static bool Divisibleby3(int number) { return number % 3 == 0; } public static bool Divisibleby5(int number) { return number % 5 == 0; } static void Main(string[] args) { var mappings = new Dictionary<Tuple<bool, bool>, string> { { new Tuple<bool, bool>(true, true), "- FizzBuzz"}, { new Tuple<bool, bool>(true, false), "- Fizz"}, { new Tuple<bool, bool>(false, true), "- Buzz"}, { new Tuple<bool, bool>(false, false), ""} }; var fizzBuzz = new FizzBuzzCalculator(mappings, Divisibleby3, Divisibleby5); for (int i = 0; i < 100; i++) { Console.WriteLine(fizzBuzz.NumberFormat(i)); } Console.ReadLine(); } } I have taken this one step further and introduced delegates that are injected into the FizzBuzz Calculator class, from an OC principle perspective it has probably made it more compliant than the previous Solution 2, but there seems to be a lot of noise. Anonymous Delegates increase the readability level, which is what I have done in Solution 4. Solution 4 – Anon Delegates public delegate bool FizzBuzzComparison(int number); public class FizzBuzzCalculator { private readonly Dictionary<Tuple<bool, bool>, string> _mappings; private readonly FizzBuzzComparison _comparison1; private readonly FizzBuzzComparison _comparison2; public FizzBuzzCalculator(Dictionary<Tuple<bool, bool>, string> mappings, FizzBuzzComparison comparison1, FizzBuzzComparison comparison2) { _mappings = mappings; _comparison1 = comparison1; _comparison2 = comparison2; } public string NumberFormat(int number) { var mappedKey = new Tuple<bool, bool>(_comparison1(number), _comparison2(number)); return String.Format("{0} {1}", number, _mappings[mappedKey]); } } class Program { static void Main(string[] args) { var mappings = new Dictionary<Tuple<bool, bool>, string> { { new Tuple<bool, bool>(true, true), "- FizzBuzz"}, { new Tuple<bool, bool>(true, false), "- Fizz"}, { new Tuple<bool, bool>(false, true), "- Buzz"}, { new Tuple<bool, bool>(false, false), ""} }; var fizzBuzz = new FizzBuzzCalculator(mappings, (n) => n % 3 == 0, (n) => n % 5 == 0); for (int i = 0; i < 100; i++) { Console.WriteLine(fizzBuzz.NumberFormat(i)); } Console.ReadLine(); } }   Using the anonymous delegates I think the noise level has now been reduced. This is where I am going to end this post, I have gone through 4 iterations of the code from the initial solution using If..Else to delegates and dictionaries. I think each approach would have it’s pro’s and con’s and depending on the intention of where the code would be used would be a large determining factor. If you can think of an alternative way to do FizzBuzz, add a comment!

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  • PostSharp, Obfuscation, and IL

    - by Simon Cooper
    Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day!

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  • PostSharp, Obfuscation, and IL

    - by simonc
    Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day! Cross posted from Simple Talk.

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  • XML over HTTP with JMS and Spring

    - by Will Sumekar
    I have a legacy HTTP server where I need to send an XML file over HTTP request (POST) using Java (not browser) and the server will respond with another XML in its HTTP response. It is similar to Web Service but there's no WSDL and I have to follow the existing XML structure to construct my XML to be sent. I have done a research and found an example that matches my requirement here. The example uses HttpClient from Apache Commons. (There are also other examples I found but they use java.net networking package (like URLConnection) which is tedious so I don't want to use them). But it's also my requirement to use Spring and JMS. I know from Spring's reference that it's possible to combine HttpClient, JMS and Spring. My question is, how? Note that it's NOT in my requirement to use HttpClient. If you have a better suggestion, I'm welcome. Appreciate it. For your reference, here's the XML-over-HTTP example I've been talking about: /* * $Header: * $Revision$ * $Date$ * ==================================================================== * * Copyright 2002-2004 The Apache Software Foundation * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * * [Additional notices, if required by prior licensing conditions] * */ import java.io.File; import java.io.FileInputStream; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.methods.InputStreamRequestEntity; import org.apache.commons.httpclient.methods.PostMethod; /** * * This is a sample application that demonstrates * how to use the Jakarta HttpClient API. * * This application sends an XML document * to a remote web server using HTTP POST * * @author Sean C. Sullivan * @author Ortwin Glück * @author Oleg Kalnichevski */ public class PostXML { /** * * Usage: * java PostXML http://mywebserver:80/ c:\foo.xml * * @param args command line arguments * Argument 0 is a URL to a web server * Argument 1 is a local filename * */ public static void main(String[] args) throws Exception { if (args.length != 2) { System.out.println( "Usage: java -classpath <classpath> [-Dorg.apache.commons."+ "logging.simplelog.defaultlog=<loglevel>]" + " PostXML <url> <filename>]"); System.out.println("<classpath> - must contain the "+ "commons-httpclient.jar and commons-logging.jar"); System.out.println("<loglevel> - one of error, "+ "warn, info, debug, trace"); System.out.println("<url> - the URL to post the file to"); System.out.println("<filename> - file to post to the URL"); System.out.println(); System.exit(1); } // Get target URL String strURL = args[0]; // Get file to be posted String strXMLFilename = args[1]; File input = new File(strXMLFilename); // Prepare HTTP post PostMethod post = new PostMethod(strURL); // Request content will be retrieved directly // from the input stream // Per default, the request content needs to be buffered // in order to determine its length. // Request body buffering can be avoided when // content length is explicitly specified post.setRequestEntity(new InputStreamRequestEntity( new FileInputStream(input), input.length())); // Specify content type and encoding // If content encoding is not explicitly specified // ISO-8859-1 is assumed post.setRequestHeader( "Content-type", "text/xml; charset=ISO-8859-1"); // Get HTTP client HttpClient httpclient = new HttpClient(); // Execute request try { int result = httpclient.executeMethod(post); // Display status code System.out.println("Response status code: " + result); // Display response System.out.println("Response body: "); System.out.println(post.getResponseBodyAsString()); } finally { // Release current connection to the connection pool // once you are done post.releaseConnection(); } } }

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  • Tuple in C# 4.0

    - by Jalpesh P. Vadgama
    C# 4.0 language includes a new feature called Tuple. Tuple provides us a way of grouping elements of different data type. That enables us to use it a lots places at practical world like we can store a coordinates of graphs etc. In C# 4.0 we can create Tuple with Create method. This Create method offer 8 overload like following. So you can group maximum 8 data types with a Tuple. Followings are overloads of a data type. Create(T1)- Which represents a tuple of size 1 Create(T1,T2)- Which represents a tuple of size 2 Create(T1,T2,T3) – Which represents a tuple of size 3 Create(T1,T2,T3,T4) – Which represents a tuple of size 4 Create(T1,T2,T3,T4,T5) – Which represents a tuple of size 5 Create(T1,T2,T3,T4,T5,T6) – Which represents a tuple of size 6 Create(T1,T2,T3,T4,T5,T6,T7) – Which represents a tuple of size 7 Create(T1,T2,T3,T4,T5,T6,T7,T8) – Which represents a tuple of size 8 Following are some example code for tuple. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create<string, string, string>("Jalpesh", "P", "Vadgama"); Console.WriteLine(tuple); var t = System.Tuple.Create<int, string>(1, "Jalpesh"); Console.WriteLine(t); } } } Following is a output of above as expected. You can also access values insides Tuple with ItemN property. Where N represents particular number of item in tuple. Following is an example of it. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create<string, string, string>("Jalpesh", "P", "Vadgama"); Console.WriteLine(tuple.Item1); Console.WriteLine(tuple.Item2); Console.WriteLine(tuple.Item3); } } } Here you can see I have printed items with Item1,Item2 and Item3 . Following is the output of above code.   Even we can create a nested tuple also following is code for nested tuple. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create(1,"Jalpesh",new Tuple<string,string>("P","Vadgama")); Console.WriteLine(tuple.Item1); Console.WriteLine(tuple.Item2); Console.WriteLine(tuple.Item3); } } } Following is a output above code as expected. As you can see there are unlimited possibilities we can do lots of things with Tuple. Hope you liked it. Stay tuned for more. Till then Happy Programming!!

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  • Browser History ASP.Net AJAX: Microsoft.Web.Preview

    - by Narendra Tiwari
    I remember in 2006 we were working on a portal for our client Venetian, Las Vegas and the portal is full of AJAX features. One of my friend facing a challange to retain browser history with all AJAX operation. In terms of user experience it is an important aspect which could not be avoided in that scenario. Well that time we have made some workarounds to achieve the same but that may not be the perfect solution. Ok.. Now with Microsoft AJAX there are a lot of such features can be achieved with optimum efficiency. Microsoft AJAX has grown its features over the past few years. Microsoft.Web.Preview.dll is an addon in conjunction with ASP.Net AJAX. It contains a control named "History" for that purpose. Source code:- http://download.microsoft.com/download/8/3/1/831ffcd7-c571-4075-b8fa-6ff678794f60/CS-ASP-ASPBrowserHistoryinAJAX_cs.zip Below is a small sample to demonstrate the control. 1/ Get dll from the above source code bin, and add reference to your web application. 2/ Rightclick on toolbox panel and Choose Item, browse assembly. now you will be able to see History control. 3/ Add below section group in web.config under <configSections> <sectionGroup name="microsoft.web.preview" type="Microsoft.Web.Preview.Configuration.PreviewSectionGroup, Microsoft.Web.Preview"> <section name="search" type="Microsoft.Web.Preview.Configuration.SearchSection, Microsoft.Web.Preview" requirePermission="false" allowDefinition="MachineToApplication"/> <section name="searchSiteMap" type="Microsoft.Web.Preview.Configuration.SearchSiteMapSection, Microsoft.Web.Preview" requirePermission="false" allowDefinition="MachineToApplication"/> <section name="diagnostics" type="Microsoft.Web.Preview.Configuration.DiagnosticsSection, Microsoft.Web.Preview" requirePermission="false" allowDefinition="MachineToApplication"/> </sectionGroup> 4/ Now create a simple webpage a textbox (txt1), button (btn1)  in an updatePanel with History control (History1). We will fill in text box and post the fom by clicking button a few times then verify if the browse history is retained. Remember button and textbox must be inside UpdatePanel and History control outside the UpdatePanel. <%@Page Language="C#" AutoEventWireup="true" CodeFile="History.aspx.cs" Inherits="History" %> <%@ Register Assembly="Microsoft.Web.Preview" Namespace="Microsoft.Web.Preview.UI.Controls" TagPrefix="cc1" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>Untitled Page</title> </head> <body> <form id="form1" runat="server"> <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true"></asp:ScriptManager> <div> <cc1:History ID="History1" runat="server" OnNavigate="History1_Navigate"> </cc1:History> <asp:UpdatePanel ID="up1" runat="server"> <ContentTemplate> <asp:TextBox ID="txt1" runat="server"></asp:TextBox><br /> <asp:Button ID="btn1" runat="server" Text="Test" OnClick="btn1_Click" /> </ContentTemplate> <Triggers> <asp:AsyncPostBackTrigger ControlID="History1" /> </Triggers> </asp:UpdatePanel> </div> </form> </body> </html> 5/ Below code to add the textbox value in history everytime we post back using btn1 click.  protected void btn1_Click(object sender, EventArgs e) { History1.AddHistoryPoint("txtState",txt1.Text); } 6/ and finally Navigate event of History control protected void History1_Navigate(object sender, Microsoft.Web.Preview.UI.Controls.HistoryEventArgs args) { string strState = string.Empty; if (args.State.ContainsKey("txtState")) { strState = (string)args.State["txtState"]; } txt1.Text = strState; } Now all set to go :) Reference: http://www.dotnetglobe.com/2008/08/using-asp.html

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  • Ubuntu + Wacom Intuos 4 + MyPaint HELP!

    - by Sativa
    Please keep in mind I'm not that computer savvy, but I will try any suggestion so please help me out! My tablet will stop working if the USB connection is ever broken, or the Ubuntu software is being updated. Sometimes it will stop working for no reason that I can see. The lights will still be on, but it won't be responsive. It doesn't work again until I restart the laptop with the tablet plugged in, which is grating if you have to do it every 25 min. or so... I'm not sure if the issue is with the port, the tablet/cable or the driver but any suggestions would be very welcome! Also, MyPaint is frequently having hiccups. It seems to save fine but at times it will randomly close down and when I open files they're often empty. They turn into 0Kb files and only contain a single empty layer. Also very grating, considering I lose days of work for no clear reason and without any heads up. Again, I'm not sure if the issue is with the port, the tablet/cable or the driver but any suggestions would be very welcome! The error message reads; Traceback (most recent call last): File "/usr/share/mypaint/gui/application.py", line 177, at_application_start(*junk=()) else: self.filehandler.open_file(fn) variables: {'fn': ('local', u'/home/maria/Desktop/Drawings/WIPs/Sativa Chibi.ora'), 'self.filehandler.open_file': ('local', <bound method FileHandler.wrapper of <gui.filehandling.FileHandler object at 0x7fdb89063a10>>)} File "/usr/share/mypaint/gui/drawwindow.py", line 60, wrapper(self=<gui.filehandling.FileHandler object>, *args=(u'/home/maria/Desktop/Drawings/WIPs/Sativa Chibi.ora',), **kwargs={}) try: func(self, *args, **kwargs) # gtk main loop may be called in here... variables: {'self': ('local', <gui.filehandling.FileHandler object at 0x7fdb89063a10>), 'args': ('local', (u'/home/maria/Desktop/Drawings/WIPs/Sativa Chibi.ora',)), 'func': ('local', <function open_file at 0x7fdb8b397b90>), 'kwargs': ('local', {})} File "/usr/share/mypaint/gui/filehandling.py", line 231, open_file(self=<gui.filehandling.FileHandler object>, filename=u'/home/maria/Desktop/Drawings/WIPs/Sativa Chibi.ora') try: self.doc.model.load(filename, feedback_cb=self.gtk_main_tick) except document.SaveLoadError, e: variables: {'self.doc.model.load': ('local', <bound method Document.load of <lib.document.Document instance at 0x7fdb8ab4f8c0>>), 'feedback_cb': (None, []), 'self.gtk_main_tick': ('local', <function gtk_main_tick at 0x7fdb8b397b18>), 'filename': ('local', u'/home/maria/Desktop/Drawings/WIPs/Sativa Chibi.ora')} File "/usr/share/mypaint/lib/document.py", line 544, load(self=<lib.document.Document instance>, filename=u'/home/maria/Desktop/Drawings/WIPs/Sativa Chibi.ora', **kwargs={'feedback_cb': <function gtk_main_tick>}) try: load(filename, **kwargs) except gobject.GError, e: variables: {'load': ('local', <bound method Document.load_ora of <lib.document.Document instance at 0x7fdb8ab4f8c0>>), 'kwargs': ('local', {'feedback_cb': <function gtk_main_tick at 0x7fdb8b397b18>}), 'filename': ('local', u'/home/maria/Desktop/Drawings/WIPs/Sativa Chibi.ora')} File "/usr/share/mypaint/lib/document.py", line 772, load_ora(self=<lib.document.Document instance>, filename=u'/home/maria/Desktop/Drawings/WIPs/Sativa Chibi.ora', feedback_cb=<function gtk_main_tick>) tempdir = tempdir.decode(sys.getfilesystemencoding()) z = zipfile.ZipFile(filename) print 'mimetype:', z.read('mimetype').strip() variables: {'zipfile.ZipFile': ('global', <class 'zipfile.ZipFile'>), 'z': (None, []), 'filename': ('local', u'/home/maria/Desktop/Drawings/WIPs/Sativa Chibi.ora')} File "/usr/lib/python2.7/zipfile.py", line 770, __init__(self=<zipfile.ZipFile object>, file=u'/home/maria/Desktop/Drawings/WIPs/Sativa Chibi.ora', mode='r', compression=0, allowZip64=False) if key == 'r': self._RealGetContents() elif key == 'w': variables: {'self._RealGetContents': ('local', <bound method ZipFile._RealGetContents of <zipfile.ZipFile object at 0x7fdb9b952790>>)} File "/usr/lib/python2.7/zipfile.py", line 811, _RealGetContents(self=<zipfile.ZipFile object>) if not endrec: raise BadZipfile, "File is not a zip file" if self.debug > 1: variables: {'BadZipfile': ('global', <class 'zipfile.BadZipfile'>)} BadZipfile: File is not a zip file

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  • C#&ndash;Using a delegate to raise an event from one class to another

    - by Bill Osuch
    Even though this may be a relatively common task for many people, I’ve had to show it to enough new developers that I figured I’d immortalize it… MSDN says “Events enable a class or object to notify other classes or objects when something of interest occurs. The class that sends (or raises) the event is called the publisher and the classes that receive (or handle) the event are called subscribers.” Any time you add a button to a Windows Form or Web app, you can subscribe to the OnClick event, and you can also create your own event handlers to pass events between classes. Here I’ll show you how to raise an event from a separate class to a console application (or Windows Form). First, create a console app project (you could create a Windows Form, but this is easier for this demo). Add a class file called MyEvent.cs (it doesn’t really need to be a separate file, this is just for clarity) with the following code: public delegate void MyHandler1(object sender, MyEvent e); public class MyEvent : EventArgs {     public string message; } Your event can have whatever public properties you like; here we’re just got a single string. Next, add a class file called WorkerDLL.cs; this will simulate the class that would be doing all the work in the project. Add the following code: class WorkerDLL {     public event MyHandler1 Event1;     public WorkerDLL()     {     }     public void DoWork()     {         FireEvent("From Worker: Step 1");         FireEvent("From Worker: Step 5");         FireEvent("From Worker: Step 10");     }     private void FireEvent(string message)     {         MyEvent e1 = new MyEvent();         e1.message = message;         if (Event1 != null)         {             Event1(this, e1);         }         e1 = null;     } } Notice that the FireEvent method creates an instance of the MyEvent class and passes it to the Event1 handler (which we’ll create in just a second). Finally, add the following code to Program.cs: static void Main(string[] args) {     Program p = new Program(args); } public Program(string[] args) {     Console.WriteLine("From Console: Creating DLL");     WorkerDLL wd = new WorkerDLL();     Console.WriteLine("From Console: Wiring up event handler");     WireEventHandlers(wd);     Console.WriteLine("From Console: Doing the work");     wd.DoWork();     Console.WriteLine("From Console: Done - press any key to finish.");     Console.ReadLine(); } private void WireEventHandlers(WorkerDLL wd) {     MyHandler1 handler = new MyHandler1(OnHandler1);     wd.Event1 += handler; } public void OnHandler1(object sender, MyEvent e) {     Console.WriteLine(e.message); } The OnHandler1 method is called any time the event handler “hears” an event matching the specified signature – you could have it log to a file, write to a database, etc. Run the app in debug mode and you should see output like this: You can distinctly see which lines were written by the console application itself (Program.cs) and which were written by the worker class (WorkerDLL.cs). Technorati Tags: Csharp

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  • Dependency Injection Introduction

    - by MarkPearl
    I recently was going over a great book called “Dependency Injection in .Net” by Mark Seeman. So far I have really enjoyed the book and would recommend anyone looking to get into DI to give it a read. Today I thought I would blog about the first example Mark gives in his book to illustrate some of the benefits that DI provides. The ones he lists are Late binding Extensibility Parallel Development Maintainability Testability To illustrate some of these benefits he gives a HelloWorld example using DI that illustrates some of the basic principles. It goes something like this… class Program { static void Main(string[] args) { var writer = new ConsoleMessageWriter(); var salutation = new Salutation(writer); salutation.Exclaim(); Console.ReadLine(); } } public interface IMessageWriter { void Write(string message); } public class ConsoleMessageWriter : IMessageWriter { public void Write(string message) { Console.WriteLine(message); } } public class Salutation { private readonly IMessageWriter _writer; public Salutation(IMessageWriter writer) { _writer = writer; } public void Exclaim() { _writer.Write("Hello World"); } }   If you had asked me a few years ago if I had thought this was a good approach to solving the HelloWorld problem I would have resounded “No”. How could the above be better than the following…. class Program { static void Main(string[] args) { Console.WriteLine("Hello World"); Console.ReadLine(); } }  Today, my mind-set has changed because of the pain of past programs. So often we can look at a small snippet of code and make judgements when we need to keep in mind that we will most probably be implementing these patterns in projects with hundreds of thousands of lines of code and in projects that we have tests that we don’t want to break and that’s where the first solution outshines the latter. Let’s see if the first example achieves some of the outcomes that were listed as benefits of DI. Could I test the first solution easily? Yes… We could write something like the following using NUnit and RhinoMocks… [TestFixture] public class SalutationTests { [Test] public void ExclaimWillWriteCorrectMessageToMessageWriter() { var writerMock = MockRepository.GenerateMock<IMessageWriter>(); var sut = new Salutation(writerMock); sut.Exclaim(); writerMock.AssertWasCalled(x => x.Write("Hello World")); } }   This would test the existing code fine. Let’s say we then wanted to extend the original solution so that we had a secure message writer. We could write a class like the following… public class SecureMessageWriter : IMessageWriter { private readonly IMessageWriter _writer; private readonly string _secretPassword; public SecureMessageWriter(IMessageWriter writer, string secretPassword) { _writer = writer; _secretPassword = secretPassword; } public void Write(string message) { if (_secretPassword == "Mark") { _writer.Write(message); } else { _writer.Write("Unauthenticated"); } } }   And then extend our implementation of the program as follows… class Program { static void Main(string[] args) { var writer = new SecureMessageWriter(new ConsoleMessageWriter(), "Mark"); var salutation = new Salutation(writer); salutation.Exclaim(); Console.ReadLine(); } }   Our application has now been successfully extended and yet we did very little code change. In addition, our existing tests did not break and we would just need add tests for the extended functionality. Would this approach allow parallel development? Well, I am in two camps on parallel development but with some planning ahead of time it would allow for it as you would simply need to decide on the interface signature and could then have teams develop different sections programming to that interface. So,this was really just a quick intro to some of the basic concepts of DI that Mark introduces very successfully in his book. I am hoping to blog about this further as I continue through the book to list some of the more complex implementations of containers.

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  • Paste Functionality for WPF DataGrid with DataGridTemplateColumns

    - by zmang
    Hi. I recently started using the WPF Datagrid with DataGridTemplateColumns containing the WPF AutoCompleteBox, but I'm finding trouble in implementing Clipboard.Paste functionality for these DataGridTemplateColumns. I've managed to get Clipboard.Paste working with built-in DataGridColumns via Vishal's guide here, but it doesn't work with DataGridTemplateColumns. Delving into the OnPastingCellClipboardContent method in the DataGridColumn class, it appears that fe.GetBindingExpression(CellValueProperty) is returning null rather than the required BindingExpression. Can anyone point me to the right direction? public virtual void OnPastingCellClipboardContent(object item, object cellContent) { BindingBase binding = ClipboardContentBinding; if (binding != null) { // Raise the event to give a chance for external listeners to modify the cell content // before it gets stored into the cell if (PastingCellClipboardContent != null) { DataGridCellClipboardEventArgs args = new DataGridCellClipboardEventArgs(item, this, cellContent); PastingCellClipboardContent(this, args); cellContent = args.Content; } // Event handlers can cancel Paste of a cell by setting its content to null if (cellContent != null) { FrameworkElement fe = new FrameworkElement(); fe.DataContext = item; fe.SetBinding(CellValueProperty, binding); fe.SetValue(CellValueProperty, cellContent); BindingExpression be = fe.GetBindingExpression(CellValueProperty); be.UpdateSource(); } } Thanks!

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  • Django 1.2 + South 0.7 + django-annoying's AutoOneToOneField leads to TypeError: 'LegacyConnection'

    - by konrad
    I'm using Django 1.2 trunk with South 0.7 and an AutoOneToOneField copied from django-annoying. South complained that the field does not have rules defined and the new version of South no longer has an automatic field type parser. So I read the South documentation and wrote the following definition (basically an exact copy of the OneToOneField rules): rules = [ ( (AutoOneToOneField), [], { "to": ["rel.to", {}], "to_field": ["rel.field_name", {"default_attr": "rel.to._meta.pk.name"}], "related_name": ["rel.related_name", {"default": None}], "db_index": ["db_index", {"default": True}], }, ) ] from south.modelsinspector import add_introspection_rules add_introspection_rules(rules, ["^myapp"]) Now South raises the following error when I do a schemamigration. Traceback (most recent call last): File "manage.py", line 11, in <module> execute_manager(settings) File "django/core/management/__init__.py", line 438, in execute_manager utility.execute() File "django/core/management/__init__.py", line 379, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "django/core/management/base.py", line 196, in run_from_argv self.execute(*args, **options.__dict__) File "django/core/management/base.py", line 223, in execute output = self.handle(*args, **options) File "South-0.7-py2.6.egg/south/management/commands/schemamigration.py", line 92, in handle (k, v) for k, v in freezer.freeze_apps([migrations.app_label()]).items() File "South-0.7-py2.6.egg/south/creator/freezer.py", line 33, in freeze_apps model_defs[model_key(model)] = prep_for_freeze(model) File "South-0.7-py2.6.egg/south/creator/freezer.py", line 65, in prep_for_freeze fields = modelsinspector.get_model_fields(model, m2m=True) File "South-0.7-py2.6.egg/south/modelsinspector.py", line 322, in get_model_fields args, kwargs = introspector(field) File "South-0.7-py2.6.egg/south/modelsinspector.py", line 271, in introspector arg_defs, kwarg_defs = matching_details(field) File "South-0.7-py2.6.egg/south/modelsinspector.py", line 187, in matching_details if any([isinstance(field, x) for x in classes]): TypeError: 'LegacyConnection' object is not iterable Is this related to a recent change in Django 1.2 trunk? How do I fix this? I use this field as follows: class Bar(models.Model): foo = AutoOneToOneField("foo.Foo", primary_key=True, related_name="bar") For reference the field code from django-tagging: class AutoSingleRelatedObjectDescriptor(SingleRelatedObjectDescriptor): def __get__(self, instance, instance_type=None): try: return super(AutoSingleRelatedObjectDescriptor, self).__get__(instance, instance_type) except self.related.model.DoesNotExist: obj = self.related.model(**{self.related.field.name: instance}) obj.save() return obj class AutoOneToOneField(OneToOneField): def contribute_to_related_class(self, cls, related): setattr(cls, related.get_accessor_name(), AutoSingleRelatedObjectDescriptor(related))

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  • Blob container creation exception ...

    - by Egon
    I get an exception every time I try to create a container for the blob using the following code blobStorageType = storageAccInfo.CreateCloudBlobClient(); ContBlob = blobStorageType.GetContainerReference(containerName); //everything fine till here ; next line creates an exception ContBlob.CreateIfNotExist(); Microsoft.WindowsAzure.StorageClient.StorageClientException was unhandled Message="One of the request inputs is out of range." Source="Microsoft.WindowsAzure.StorageClient" StackTrace: at Microsoft.WindowsAzure.StorageClient.Tasks.Task1.get_Result() at Microsoft.WindowsAzure.StorageClient.Tasks.Task1.ExecuteAndWait() at Microsoft.WindowsAzure.StorageClient.TaskImplHelper.ExecuteImplWithRetry[T](Func2 impl, RetryPolicy policy) at Microsoft.WindowsAzure.StorageClient.CloudBlobContainer.CreateIfNotExist(BlobRequestOptions options) at Microsoft.WindowsAzure.StorageClient.CloudBlobContainer.CreateIfNotExist() at WebRole1.BlobFun..ctor() in C:\Users\cloud\Documents\Visual Studio 2008\Projects\CloudBlob\WebRole1\BlobFun.cs:line 58 at WebRole1.BlobFun.calling1() in C:\Users\cloud\Documents\Visual Studio 2008\Projects\CloudBlob\WebRole1\BlobFun.cs:line 29 at AzureBlobTester.Program.Main(String[] args) in C:\Users\cloud\Documents\Visual Studio 2008\Projects\CloudBlob\AzureBlobTester\Program.cs:line 19 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException: System.Net.WebException Message="The remote server returned an error: (400) Bad Request." Source="System" StackTrace: at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult) at Microsoft.WindowsAzure.StorageClient.EventHelper.ProcessWebResponse(WebRequest req, IAsyncResult asyncResult, EventHandler1 handler, Object sender) InnerException: Do you guys knw what is it that I am doing wrong ?

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  • c# SmtpClient class not able to send email using gmail

    - by Sir Psycho
    Hi, I'm having trouble with this code sending email using my gmail account. Im pulling my hair out. The same settings work fine in Thunderbird. Heres the code. I've also tried port 465 with no luck. SmtpClient ss = new SmtpClient("smtp.gmail.com", 587); ss.Credentials = new NetworkCredential("username", "pass"); ss.EnableSsl = true; ss.Timeout = 10000; ss.DeliveryMethod = SmtpDeliveryMethod.Network; ss.UseDefaultCredentials = false; MailMessage mm = new MailMessage("[email protected]", "[email protected]", "subject here", "my body"); mm.BodyEncoding = UTF8Encoding.UTF8; mm.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure; ss.Send(mm); Heres the error "The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at " Heres the stack trace at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response) at System.Net.Mail.MailCommand.Send(SmtpConnection conn, Byte[] command, String from) at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception) at System.Net.Mail.SmtpClient.Send(MailMessage message) at email_example.Program.Main(String[] args) in C:\Users\Vince\Documents\Visual Studio 2008\Projects\email example\email example\Program.cs:line 23 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart()

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  • Silverlight ComboBox Attached Behavior

    - by Mark Cooper
    I am trying to create an attached behavior that can be applied to a Silverlight ComboBox. My behavior is this: using System.Windows.Controls; using System.Windows; using System.Windows.Controls.Primitives; namespace AttachedBehaviours { public class ConfirmChangeBehaviour { public static bool GetConfirmChange(Selector cmb) { return (bool)cmb.GetValue(ConfirmChangeProperty); } public static void SetConfirmChange(Selector cmb, bool value) { cmb.SetValue(ConfirmChangeProperty, value); } public static readonly DependencyProperty ConfirmChangeProperty = DependencyProperty.RegisterAttached("ConfirmChange", typeof(bool), typeof(Selector), new PropertyMetadata(true, ConfirmChangeChanged)); public static void ConfirmChangeChanged(DependencyObject d, DependencyPropertyChangedEventArgs args) { Selector instance = d as Selector; if (args.NewValue is bool == false) return; if ((bool)args.NewValue) instance.SelectionChanged += OnSelectorSelectionChanged; else instance.SelectionChanged -= OnSelectorSelectionChanged; } static void OnSelectorSelectionChanged(object sender, RoutedEventArgs e) { Selector item = e.OriginalSource as Selector; MessageBox.Show("Unsaved changes. Are you sure you want to change teams?"); } } } This is used in XAML as this: <UserControl x:Class="AttachedBehaviours.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:this="clr-namespace:AttachedBehaviours" mc:Ignorable="d"> <Grid x:Name="LayoutRoot"> <StackPanel> <ComboBox ItemsSource="{Binding Teams}" this:ConfirmChangeBehaviour.ConfirmChange="true" > </ComboBox> </StackPanel> </Grid> </UserControl> I am getting an error: Unknown attribute ConfirmChangeBehaviour.ConfirmChange on element ComboBox. [Line: 13 Position: 65] Intellisense is picking up the behavior, why is this failing at runtime? Thanks, Mark EDIT: Register() changed to RegisterAttached(). Same error appears.

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  • MonoTouch: using embedded resx files on iPhone build

    - by bright
    I'm able to load and access resx files in Simulator builds of my iPhone app built using MonoTouch. The resx file entry in the csproj file looks like: <ItemGroup> <EmbeddedResource Include="MapMenu\Resources\MapMenu.resx"> <Generator>ResXFileCodeGenerator</Generator> <LastGenOutput>MapMenu.Designer.cs</LastGenOutput> </EmbeddedResource> </ItemGroup> The .resx file itself has an entry like this: <data name="Main_Menu" type="System.Resources.ResXFileRef, System.Windows.Forms"> <value>Main Menu.mm;System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089;Windows-1252</value> </data> and the generated MapMenu.Designer.cs file has this: internal static string Main_Menu { get { return ResourceManager.GetString("Main_Menu", resourceCulture); } } As mentioned above, calling the Main_Menu accessor works fine on the simulator. On the device, however, it produces: <Notice>: Unhandled Exception: System.MissingMethodException: No constructor found for System.Resources.RuntimeResourceSet::.ctor(System.IO.UnmanagedMemoryStream) <Notice>: at System.Activator.CreateInstance (System.Type type, BindingFlags bindingAttr, System.Reflection.Binder binder, System.Object[] args, System.Globalization.CultureInfo culture, System.Object[] activationAttributes) [0x00000] in <filename unknown>:0 <Notice>: at System.Activator.CreateInstance (System.Type type, System.Object[] args, System.Object[] activationAttributes) [0x00000] in <filename unknown>:0 <Notice>: at System.Activator.CreateInstance (System.Type type, System.Object[] args) [0x00000] in <filename unknown>:0 <Notice>: at System.Resources.ResourceManager.InternalGetResourceSet (System.Globalization.CultureInfo culture, Boolean createIfNotExists, Boolean tryParents) [0x00000] in <filename unknown>:0 <Notice>: at System.Resources.ResourceManager.GetString (System.String name, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0 <Notice>: at MapMenu.Resources.MapMenu.get_Main_Menu () [0x00000] in <filename unknown>:0 Did a few sanity checks, and am wondering at this point if this really is missing functionality in Monotouch. Thanks,

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  • Problem with Java Applet <--> Javascript communication

    - by davr
    I'm having trouble getting a Java Applet to communicate with the Javascript code on the page the applet is hosted on. It works sometimes, but othertimes it throws an obscure exception, that googling for has not turned up any useful information, besides a few Java bug reports that were never resolved (thanks Sun). Here is the code I am using: JSObject win = JSObject.getWindow(this); Object[] args = new Object[1]; args[0] = "test argument"; String result = (String) win.call("testJSfunc", args); // XXX Here is the exception I get on the line marked // XXX. Note that it is intermittent. Often it works, but sometimes it does not, using the same exact code. Reloading the page repeatedly will produce the error pretty quickly. netscape.javascript.JSException: No registered plugin for applet ID 1 at sun.plugin2.main.client.MessagePassingJSObject.newJSException(Unknown Source) at sun.plugin2.main.client.MessagePassingJSObject.waitForReply(Unknown Source) at sun.plugin2.main.client.MessagePassingJSObject.call(Unknown Source) at TestApplet.testCallJS(TestApplet.java:159) at TestApplet.init(TestApplet.java:139) at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Is there another more stable way of communicating between Java and Javascript that I should be using?

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  • Informix, NHibernate, TransactionScope interaction difficulties

    - by John Prideaux
    I have a small program that is trying to wrap an NHibernate insert into an Informix database in a TransactionScope object using the Informix .NET Provider. I am getting the error specified below. The code without the TransactionScope object works -- including when the insert is wrapped in an NHibernate session transaction. Any ideas on what the problem is? BTW, without the EnterpriseServicesInterop, the Informix .NET Provider will not participate in a TransactionScope transaction (verified without NHibernate involved). Code Snippet: public static void TestTScope() { Employee johnp = new Employee { name = "John Prideaux" }; using (TransactionScope tscope = new TransactionScope( TransactionScopeOption.Required, new TransactionOptions() { Timeout = new TimeSpan(0, 1, 0), IsolationLevel = IsolationLevel.ReadCommitted }, EnterpriseServicesInteropOption.Full)) { using (ISession session = OpenSession()) { session.Save(johnp); Console.WriteLine("Saved John to the database"); } } Console.WriteLine("Transaction should be rolled back"); } static ISession OpenSession() { if (factory == null) { Configuration c = new Configuration(); c.AddAssembly(Assembly.GetCallingAssembly()); factory = c.BuildSessionFactory(); } return factory.OpenSession(); } static ISessionFactory factory; Stack Trace: NHibernate.ADOException was unhandled Message="Could not close IBM.Data.Informix.IfxConnection connection" Source="NHibernate" StackTrace: at NHibernate.Connection.ConnectionProvider.CloseConnection(IDbConnection conn) at NHibernate.Connection.DriverConnectionProvider.CloseConnection(IDbConnection conn) at NHibernate.Tool.hbm2ddl.SuppliedConnectionProviderConnectionHelper.Release() at NHibernate.Tool.hbm2ddl.SchemaMetadataUpdater.GetReservedWords(Dialect dialect, IConnectionHelper connectionHelper) at NHibernate.Tool.hbm2ddl.SchemaMetadataUpdater.Update(ISessionFactory sessionFactory) at NHibernate.Impl.SessionFactoryImpl..ctor(Configuration cfg, IMapping mapping, Settings settings, EventListeners listeners) at NHibernate.Cfg.Configuration.BuildSessionFactory() at HelloNHibernate.Employee.OpenSession() in D:\Development\ScratchProject\HelloNHibernate\Employee.cs:line 73 at HelloNHibernate.Employee.TestTScope() in D:\Development\ScratchProject\HelloNHibernate\Employee.cs:line 53 at HelloNHibernate.Program.Main(String[] args) in D:\Development\ScratchProject\HelloNHibernate\Program.cs:line 19 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException: IBM.Data.Informix.IfxException Message="ERROR - no error information available" Source="IBM.Data.Informix" ErrorCode=-2147467259 StackTrace: at IBM.Data.Informix.IfxConnection.HandleError(IntPtr hHandle, SQL_HANDLE hType, RETCODE retcode) at IBM.Data.Informix.IfxConnection.DisposeClose() at IBM.Data.Informix.IfxConnection.Close() at NHibernate.Connection.ConnectionProvider.CloseConnection(IDbConnection conn) InnerException:

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  • Java RMI AccessControlException: access denied

    - by Gwilym
    Hey im getting a AccessControlException: access denied when attempting to start up a RMI app im writing, I cant work out why I get this exception if I open it on the default port 1099, or on another dynamic port, my policy file currently grants everything (will change when app is finished). I am stuck as to where It is going wrong, any help would but of great use My code public class Main { /** * @param args the command line arguments */ public static void main(String[] args) throws RemoteException, AlreadyBoundException, MalformedURLException { if (System.getSecurityManager() == null) { System.setSecurityManager ( new RMISecurityManager() ); } CreditCardServer ccs = new CreditCardServer(); int port = 1099; try { port = Integer.valueOf(args[0]); } catch (Exception e) { System.out.println("Invlaid Port"); } if (((port <= 65535) && (port >= 49152)) || port ==1099) { System.out.println("Valid Port"); } else { port = 1099; System.out.println("Port not in Dynamic Range 49152<-->65535"); } System.out.println(port); LocateRegistry.createRegistry(port); LocateRegistry.getRegistry().bind("CreditCardServer", ccs); while (true) { //hum? } } } The Stack Trace vega3 [ia32.linux] 23% java -Djava.security.policy=wideopen.policy -jar "BookStore-CreditCardServer.jar 65000" Valid Port 65000 Exception in thread "main" java.security.AccessControlException: access denied (java.net.SocketPermission 127.0.0.1:1099 connect,resolve) at java.security.AccessControlContext.checkPermission(AccessControlContext.java:342) at java.security.AccessController.checkPermission(AccessController.java:553) at java.lang.SecurityManager.checkPermission(SecurityManager.java:549) at java.lang.SecurityManager.checkConnect(SecurityManager.java:1051) at java.net.Socket.connect(Socket.java:536) at java.net.Socket.connect(Socket.java:492) at java.net.Socket.<init>(Socket.java:389) at java.net.Socket.<init>(Socket.java:203) at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:40) at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:146) at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:613) at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:216) at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:202) at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:340) at sun.rmi.registry.RegistryImpl_Stub.bind(Unknown Source) at bookstorecreditcardserver.Main.main(Main.java:56) My Policy File grant { // Allow everything for now permission java.security.AllPermission; };

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  • What makes static initialization functions good, bad, or otherwise?

    - by Richard Levasseur
    Suppose you had code like this: _READERS = None _WRITERS = None def Init(num_readers, reader_params, num_writers, writer_params, ...args...): ...logic... _READERS = new ReaderPool(num_readers, reader_params) _WRITERS = new WriterPool(num_writers, writer_params) ...more logic... class Doer: def __init__(...args...): ... def Read(self, ...args...): c = _READERS.get() try: ...work with conn finally: _READERS.put(c) def Writer(...): ...similar to Read()... To me, this is a bad pattern to follow, some cons: Doers can be created without its preconditions being satisfied The code isn't easily testable because ConnPool can't be directly mocked out. Init has to be called right the first time. If its changed so it can be called multiple times, extra logic has to be added to check if variables are already defined, and lots of NULL values have to be passed around to skip re-initializing. In the event of threads, the above becomes more complicated by adding locking Globals aren't being used to communicate state (which isn't strictly bad, but a code smell) On the other hand, some pros: its very convenient to call Init(5, "user/pass", 2, "user/pass") It simple and "clean" Personally, I think the cons outweigh the pros, that is, testability and assured preconditions outweigh simplicity and convenience.

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  • Should an Event that has no arguments define its own custom EventArgs or simply use System.EventArgs

    - by Mike Rosenblum
    I have an event that is currently defined with no event arguments. That is, the EventArgs it sends is EventArgs.Empty. In this case, it is simplest to declare my Event handler as: EventHandler<System.EventArgs> MyCustomEvent; I do not plan on adding any event arguments to this event, but it is possible that any code could need to change in the future. Therefore, I am leaning towards having all my events always create an empty event args type that inheretis from System.EventArgs, even if there are no event args currently needed. Something like this: public class MyCustomEventArgs : EventArgs { } And then my event definition becomes the following: EventHandler<MyCustomEventArgs> MyCustomEvent; So my question is this: is it better to define my own MyCustomEventArgs, even if it does not add anything beyond inheriting from System.EventArgs, so that event arguments could be added in the future more easily? Or is it better to explicitly define my event as returning System.EventArgs, so that it is clearer to the user that there are no extra event args? I am leaning towards creating custom event arguments for all my events, even if the event arguments are empty. But I was wondering if others thought that making it clearer to the user that the event arguments are empty would be better? Much thanks in advance, Mike

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  • Delegate within a delegate in VB.NET.

    - by Topdown
    I am trying to write a VB.NET alternative to a C# anonymous function. I wish to call Threading.SynchronizationContext.Current.Send which expects a delegate of type Threading.SendOrPostCallback to be passed to it. The background is here, but because I wish to both pass in a string to MessageBox.Show and also capture the DialogResult I need to define another delegate within. I am struggling with the VB.NET syntax, both from the traditional delegate style, and lambda functions. My go at the traditional syntax is below, but I have gut feeling it should be much simpler than this: Private Sub CollectMesssageBoxResultFromUserAsDelegate(ByVal messageToShow As String, ByRef wasCanceled As Boolean) wasCanceled = False If Windows.Forms.MessageBox.Show(String.Format("{0}{1}Please press [OK] to ignore this error and continue, or [Cancel] to stop here.", messageToShow), "Continue", Windows.Forms.MessageBoxButtons.OKCancel, Windows.Forms.MessageBoxIcon.Exclamation) = Windows.Forms.DialogResult.Cancel Then wasCanceled = True End If End Sub Private Delegate Sub ShowMessageBox(ByVal messageToShow As String, ByRef canceled As Boolean) Private Sub AskUserWhetherToCancel(ByVal message As String, ByVal args As CancelEventArgs) If args Is Nothing Then args = New System.ComponentModel.CancelEventArgs With {.Cancel = False} Dim wasCancelClicked As Boolean Dim firstDelegate As New ShowMessageBox(AddressOf CollectMesssageBoxResultFromUserAsDelegate) '…. Now what?? 'I can’t declare SendOrPostCallback as below: 'Dim myDelegate As New Threading.SendOrPostCallback(AddressOf firstDelegate) End Sub

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