static constructor - Page 124

Code Contracts: Hiding ContractException

- by DigiMortal

It’s time to move on and improve my randomizer I wrote for an example of static checking of code contracts. In this posting I will modify contracts and give some explanations about pre-conditions and post-conditions. Also I will show you how to avoid ContractExceptions and how to replace them with your own exceptions. As a first thing let’s take a look at my randomizer. public class Randomizer { public static int GetRandomFromRange(int min, int max) { var rnd = new Random(); return rnd.Next(min, max); } public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires(min < max, "Min must be less than max"); var rnd = new Random(); return rnd.Next(min, max); } } We have some problems here. We need contract for method output and we also need some better exception handling mechanism. As ContractException as type is hidden from us we have to switch from ContractException to some other Exception type that we can catch. Adding post-condition Pre-conditions are contracts for method’s input interface. Read it as follows: pre-conditions make sure that all conditions for method’s successful run are met. Post-conditions are contracts for output interface of method. So, post-conditions are for output arguments and return value. My code misses the post-condition that checks return value. Return value in this case must be greater or equal to minimum value and less or equal to maximum value. To make sure that method can run only the correct value I added call to Contract.Ensures() method. public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires(min < max, "Min must be less than max"); Contract.Ensures( Contract.Result<int>() >= min && Contract.Result<int>() <= max, "Return value is out of range" ); var rnd = new Random(); return rnd.Next(min, max); } I think that the line I added does not need any further comments. Avoiding ContractException for input interface ContractException lives in hidden namespace and we cannot see it at design time. But it is common exception type for all contract exceptions that we do not switch over to some other type. The case of Contract.Requires() method is simple: we can tell it what kind of exception we need if something goes wrong with contract it ensures. public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires<ArgumentOutOfRangeException>( min < max, "Min must be less than max" ); Contract.Ensures( Contract.Result<int>() >= min && Contract.Result<int>() <= max, "Return value is out of range" ); var rnd = new Random(); return rnd.Next(min, max); } Now, if we violate the input interface contract giving min value that is not less than max value we get ArgumentOutOfRangeException. Avoiding ContractException for output interface Output interface is more complex to control. We cannot give exception type there and hope that this type of exception will be thrown if something goes wrong. Instead we have to use delegate that gathers information about problem and throws the exception we expect to be thrown. From documentation you can find the following example about the delegate I mentioned. Contract.ContractFailed += (sender, e) => { e.SetHandled(); e.SetUnwind(); // cause code to abort after event Assert.Fail(e.FailureKind.ToString() + ":" + e.DebugMessage); }; We can use this delegate to throw the Exception. Let’s move the code to separate method too. Here is our method that uses now ContractException hiding. public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires(min < max, "Min must be less than max"); Contract.Ensures( Contract.Result<int>() >= min && Contract.Result<int>() <= max, "Return value is out of range" ); Contract.ContractFailed += Contract_ContractFailed; var rnd = new Random(); return rnd.Next(min, max)+1000; } And here is the delegate that creates exception. public static void Contract_ContractFailed(object sender, ContractFailedEventArgs e) { e.SetHandled(); e.SetUnwind(); throw new Exception(e.FailureKind.ToString() + ":" + e.Message); } Basically we can do in this delegate whatever we like to do with output interface errors. We can even introduce our own contract exception type. As you can see later then ContractFailed event is very useful at unit testing.

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Generate Strongly Typed Observable Events for the Reactive Extensions for .NET (Rx)

- by Bobby Diaz

I must have tried reading through the various explanations and introductions to the new Reactive Extensions for .NET before the concepts finally started sinking in. The article that gave me the ah-ha moment was over on SilverlightShow.net and titled Using Reactive Extensions in Silverlight. The author did a good job comparing the "normal" way of handling events vs. the new "reactive" methods. Admittedly, I still have more to learn about the Rx Framework, but I wanted to put together a sample project so I could start playing with the new Observable and IObservable<T> constructs. I decided to throw together a whiteboard application in Silverlight based on the Drawing with Rx example on the aforementioned article. At the very least, I figured I would learn a thing or two about a new technology, but my real goal is to create a fun application that I can share with the kids since they love drawing and coloring so much! Here is the code sample that I borrowed from the article: var mouseMoveEvent = Observable.FromEvent<MouseEventArgs>(this, "MouseMove"); var mouseLeftButtonDown = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonDown"); var mouseLeftButtonUp = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonUp"); var draggingEvents = from pos in mouseMoveEvent .SkipUntil(mouseLeftButtonDown) .TakeUntil(mouseLeftButtonUp) .Let(mm => mm.Zip(mm.Skip(1), (prev, cur) => new { X2 = cur.EventArgs.GetPosition(this).X, X1 = prev.EventArgs.GetPosition(this).X, Y2 = cur.EventArgs.GetPosition(this).Y, Y1 = prev.EventArgs.GetPosition(this).Y })).Repeat() select pos; draggingEvents.Subscribe(p => { Line line = new Line(); line.Stroke = new SolidColorBrush(Colors.Black); line.StrokeEndLineCap = PenLineCap.Round; line.StrokeLineJoin = PenLineJoin.Round; line.StrokeThickness = 5; line.X1 = p.X1; line.Y1 = p.Y1; line.X2 = p.X2; line.Y2 = p.Y2; this.LayoutRoot.Children.Add(line); }); One thing that was nagging at the back of my mind was having to deal with the event names as strings, as well as the verbose syntax for the Observable.FromEvent<TEventArgs>() method. I came up with a couple of static/helper classes to resolve both issues and also created a T4 template to auto-generate these helpers for any .NET type. Take the following code from the above example: var mouseMoveEvent = Observable.FromEvent<MouseEventArgs>(this, "MouseMove"); var mouseLeftButtonDown = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonDown"); var mouseLeftButtonUp = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonUp"); Turns into this with the new static Events class: var mouseMoveEvent = Events.Mouse.Move.On(this); var mouseLeftButtonDown = Events.Mouse.LeftButtonDown.On(this); var mouseLeftButtonUp = Events.Mouse.LeftButtonUp.On(this); Or better yet, just remove the variable declarations altogether: var draggingEvents = from pos in Events.Mouse.Move.On(this) .SkipUntil(Events.Mouse.LeftButtonDown.On(this)) .TakeUntil(Events.Mouse.LeftButtonUp.On(this)) .Let(mm => mm.Zip(mm.Skip(1), (prev, cur) => new { X2 = cur.EventArgs.GetPosition(this).X, X1 = prev.EventArgs.GetPosition(this).X, Y2 = cur.EventArgs.GetPosition(this).Y, Y1 = prev.EventArgs.GetPosition(this).Y })).Repeat() select pos; The Move, LeftButtonDown and LeftButtonUp members of the Events.Mouse class are readonly instances of the ObservableEvent<TTarget, TEventArgs> class that provide type-safe access to the events via the On() method. Here is the code for the class: using System; using System.Collections.Generic; using System.Linq; namespace System.Linq { /// <summary> /// Represents an event that can be managed via the <see cref="Observable"/> API. /// </summary> /// <typeparam name="TTarget">The type of the target.</typeparam> /// <typeparam name="TEventArgs">The type of the event args.</typeparam> public class ObservableEvent<TTarget, TEventArgs> where TEventArgs : EventArgs { /// <summary> /// Initializes a new instance of the <see cref="ObservableEvent"/> class. /// </summary> /// <param name="eventName">Name of the event.</param> protected ObservableEvent(String eventName) { EventName = eventName; } /// <summary> /// Registers the specified event name. /// </summary> /// <param name="eventName">Name of the event.</param> /// <returns></returns> public static ObservableEvent<TTarget, TEventArgs> Register(String eventName) { return new ObservableEvent<TTarget, TEventArgs>(eventName); } /// <summary> /// Creates an enumerable sequence of event values for the specified target. /// </summary> /// <param name="target">The target.</param> /// <returns></returns> public IObservable<IEvent<TEventArgs>> On(TTarget target) { return Observable.FromEvent<TEventArgs>(target, EventName); } /// <summary> /// Gets or sets the name of the event. /// </summary> /// <value>The name of the event.</value> public string EventName { get; private set; } } } And this is how it's used: /// <summary> /// Categorizes <see cref="ObservableEvents"/> by class and/or functionality. /// </summary> public static partial class Events { /// <summary> /// Implements a set of predefined <see cref="ObservableEvent"/>s /// for the <see cref="System.Windows.System.Windows.UIElement"/> class /// that represent mouse related events. /// </summary> public static partial class Mouse { /// <summary>Represents the MouseMove event.</summary> public static readonly ObservableEvent<UIElement, MouseEventArgs> Move = ObservableEvent<UIElement, MouseEventArgs>.Register("MouseMove"); // additional members omitted... } } The source code contains a static Events class with prefedined members for various categories (Key, Mouse, etc.). There is also an Events.tt template that you can customize to generate additional event categories for any .NET type. All you should have to do is add the name of your class to the types collection near the top of the template: types = new Dictionary<String, Type>() { //{ "Microsoft.Maps.MapControl.Map, Microsoft.Maps.MapControl", null } { "System.Windows.FrameworkElement, System.Windows", null }, { "Whiteboard.MainPage, Whiteboard", null } }; The template is also a bit rough at this point, but at least it generates code that *should* compile. Please let me know if you run into any issues with it. Some people have reported errors when trying to use T4 templates within a Silverlight project, but I was able to get it to work with a little black magic... You can download the source code for this project or play around with the live demo. Just be warned that it is at a very early stage so don't expect to find much today. I plan on adding alot more options like pen colors and sizes, saving, printing, etc. as time permits. HINT: hold down the ESC key to erase! Enjoy! Additional Resources Using Reactive Extensions in Silverlight DevLabs: Reactive Extensions for .NET (Rx) Rx Framework Part III - LINQ to Events - Generating GetEventName() Wrapper Methods using T4

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jBullet Collision/Physics not working correctly

- by Kenneth Bray

Below is the code for one of my objects in the game I am creating (yes although this is a cube, I am not making anything remotely like MineCraft), and my issue is I while the cube will display and is does follow the physics if the cube falls, it does not interact with any other objects in the game. If I was to have multiple cubes in screen at once they all just sit there, or shoot off in all directions never stopping. Anyway, I am new to jBullet, and any help would be appreciated. package Object; import static org.lwjgl.opengl.GL11.GL_QUADS; import static org.lwjgl.opengl.GL11.glBegin; import static org.lwjgl.opengl.GL11.glColor3f; import static org.lwjgl.opengl.GL11.glEnd; import static org.lwjgl.opengl.GL11.glPopMatrix; import static org.lwjgl.opengl.GL11.glPushMatrix; import static org.lwjgl.opengl.GL11.glVertex3f; import javax.vecmath.Matrix4f; import javax.vecmath.Quat4f; import javax.vecmath.Vector3f; import com.bulletphysics.collision.shapes.BoxShape; import com.bulletphysics.collision.shapes.CollisionShape; import com.bulletphysics.dynamics.RigidBody; import com.bulletphysics.dynamics.RigidBodyConstructionInfo; import com.bulletphysics.linearmath.DefaultMotionState; import com.bulletphysics.linearmath.Transform; public class Cube { // Cube size/shape variables private float size; boolean cubeCollidable; boolean cubeDestroyable; // Position variables - currently this defines the center of the cube private float posX; private float posY; private float posZ; // Rotation variables - should be between 0 and 359, might consider letting rotation go higher though I can't think of a purpose currently private float rotX; private float rotY; private float rotZ; //collision shape is a box shape CollisionShape fallShape; // setup the motion state for the ball DefaultMotionState fallMotionState; Vector3f fallInertia = new Vector3f(0, 1, 0); RigidBodyConstructionInfo fallRigidBodyCI; public RigidBody fallRigidBody; int mass = 1; // Constructor public Cube(float pX, float pY, float pZ, float pSize) { posX = pX; posY = pY; posZ = pZ; size = pSize; rotX = 0; rotY = 0; rotZ = 0; // define the physics based on the values passed in fallShape = new BoxShape(new Vector3f(size, size, size)); fallMotionState = new DefaultMotionState(new Transform(new Matrix4f(new Quat4f(0, 0, 0, 1), new Vector3f(0, 50, 0), 1f))); fallRigidBodyCI = new RigidBodyConstructionInfo(mass, fallMotionState, fallShape, fallInertia); fallRigidBody = new RigidBody(fallRigidBodyCI); } public void Update() { Transform trans = new Transform(); fallRigidBody.getMotionState().getWorldTransform(trans); posY = trans.origin.x; posX = trans.origin.y; posZ = trans.origin.z; } public void Draw() { fallShape.calculateLocalInertia(mass, fallInertia); // center point posX, posY, posZ float radius = size / 2; //top glPushMatrix(); glBegin(GL_QUADS); { glColor3f(1.0f,0.0f,0.0f); // red glVertex3f(posX + radius, posY + radius, posZ - radius); glVertex3f(posX - radius, posY + radius, posZ - radius); glVertex3f(posX - radius, posY + radius, posZ + radius); glVertex3f(posX + radius, posY + radius, posZ + radius); } glEnd(); glPopMatrix(); //bottom glPushMatrix(); glBegin(GL_QUADS); { glColor3f(1.0f,1.0f,0.0f); // ?? color glVertex3f(posX + radius, posY - radius, posZ + radius); glVertex3f(posX - radius, posY - radius, posZ + radius); glVertex3f(posX - radius, posY - radius, posZ - radius); glVertex3f(posX + radius, posY - radius, posZ - radius); } glEnd(); glPopMatrix(); //right side glPushMatrix(); glBegin(GL_QUADS); { glColor3f(1.0f,0.0f,1.0f); // ?? color glVertex3f(posX + radius, posY + radius, posZ + radius); glVertex3f(posX + radius, posY - radius, posZ + radius); glVertex3f(posX + radius, posY - radius, posZ - radius); glVertex3f(posX + radius, posY + radius, posZ - radius); } glEnd(); glPopMatrix(); //left side glPushMatrix(); glBegin(GL_QUADS); { glColor3f(0.0f,1.0f,1.0f); // ?? color glVertex3f(posX - radius, posY + radius, posZ - radius); glVertex3f(posX - radius, posY - radius, posZ - radius); glVertex3f(posX - radius, posY - radius, posZ + radius); glVertex3f(posX - radius, posY + radius, posZ + radius); } glEnd(); glPopMatrix(); //front side glPushMatrix(); glBegin(GL_QUADS); { glColor3f(0.0f,0.0f,1.0f); //blue glVertex3f(posX + radius, posY + radius, posZ + radius); glVertex3f(posX - radius, posY + radius, posZ + radius); glVertex3f(posX - radius, posY - radius, posZ + radius); glVertex3f(posX + radius, posY - radius, posZ + radius); } glEnd(); glPopMatrix(); //back side glPushMatrix(); glBegin(GL_QUADS); { glColor3f(0.0f,1.0f,0.0f); // green glVertex3f(posX + radius, posY - radius, posZ - radius); glVertex3f(posX - radius, posY - radius, posZ - radius); glVertex3f(posX - radius, posY + radius, posZ - radius); glVertex3f(posX + radius, posY + radius, posZ - radius); } glEnd(); glPopMatrix(); } }

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More Fun with C# Iterators and Generators

- by James Michael Hare

In my last post, I talked quite a bit about iterators and how they can be really powerful tools for filtering a list of items down to a subset of items. This had both pros and cons over returning a full collection, which, in summary, were: Pros: If traversal is only partial, does not have to visit rest of collection. If evaluation method is costly, only incurs that cost on elements visited. Adds little to no garbage collection pressure. Cons: Very slight performance impact if you know caller will always consume all items in collection. And as we saw in the last post, that con for the cost was very, very small and only really became evident on very tight loops consuming very large lists completely. One of the key items to note, though, is the garbage! In the traditional (return a new collection) method, if you have a 1,000,000 element collection, and wish to transform or filter it in some way, you have to allocate space for that copy of the collection. That is, say you have a collection of 1,000,000 items and you want to double every item in the collection. Well, that means you have to allocate a collection to hold those 1,000,000 items to return, which is a lot especially if you are just going to use it once and toss it. Iterators, though, don't have this problem. Each time you visit the node, it would return the doubled value of the node (in this example) and not allocate a second collection of 1,000,000 doubled items. Do you see the distinction? In both cases, we're consuming 1,000,000 items. But in one case we pass back each doubled item which is just an int (for example's sake) on the stack and in the other case, we allocate a list containing 1,000,000 items which then must be garbage collected. So iterators in C# are pretty cool, eh? Well, here's one more thing a C# iterator can do that a traditional "return a new collection" transformation can't! It can return **unbounded** collections! I know, I know, that smells a lot like an infinite loop, eh? Yes and no. Basically, you're relying on the caller to put the bounds on the list, and as long as the caller doesn't you keep going. Consider this example: public static class Fibonacci { // returns the infinite fibonacci sequence public static IEnumerable<int> Sequence() { int iteration = 0; int first = 1; int second = 1; int current = 0; while (true) { if (iteration++ < 2) { current = 1; } else { current = first + second; second = first; first = current; } yield return current; } } } Whoa, you say! Yes, that's an infinite loop! What the heck is going on there? Yes, that was intentional. Would it be better to have a fibonacci sequence that returns only a specific number of items? Perhaps, but that wouldn't give you the power to defer the execution to the caller. The beauty of this function is it is as infinite as the sequence itself! The fibonacci sequence is unbounded, and so is this method. It will continue to return fibonacci numbers for as long as you ask for them. Now that's not something you can do with a traditional method that would return a collection of ints representing each number. In that case you would eventually run out of memory as you got to higher and higher numbers. This method, though, never runs out of memory. Now, that said, you do have to know when you use it that it is an infinite collection and bound it appropriately. Fortunately, Linq provides a lot of these extension methods for you! Let's say you only want the first 10 fibonacci numbers: foreach(var fib in Fibonacci.Sequence().Take(10)) { Console.WriteLine(fib); } Or let's say you only want the fibonacci numbers that are less than 100: foreach(var fib in Fibonacci.Sequence().TakeWhile(f => f < 100)) { Console.WriteLine(fib); } So, you see, one of the nice things about iterators is their power to work with virtually any size (even infinite) collections without adding the garbage collection overhead of making new collections. You can also do fun things like this to make a more "fluent" interface for for loops: // A set of integer generator extension methods public static class IntExtensions { // Begins counting to inifity, use To() to range this. public static IEnumerable<int> Every(this int start) { // deliberately avoiding condition because keeps going // to infinity for as long as values are pulled. for (var i = start; ; ++i) { yield return i; } } // Begins counting to infinity by the given step value, use To() to public static IEnumerable<int> Every(this int start, int byEvery) { // deliberately avoiding condition because keeps going // to infinity for as long as values are pulled. for (var i = start; ; i += byEvery) { yield return i; } } // Begins counting to inifity, use To() to range this. public static IEnumerable<int> To(this int start, int end) { for (var i = start; i <= end; ++i) { yield return i; } } // Ranges the count by specifying the upper range of the count. public static IEnumerable<int> To(this IEnumerable<int> collection, int end) { return collection.TakeWhile(item => item <= end); } } Note that there are two versions of each method. One that starts with an int and one that starts with an IEnumerable<int>. This is to allow more power in chaining from either an existing collection or from an int. This lets you do things like: // count from 1 to 30 foreach(var i in 1.To(30)) { Console.WriteLine(i); } // count from 1 to 10 by 2s foreach(var i in 0.Every(2).To(10)) { Console.WriteLine(i); } // or, if you want an infinite sequence counting by 5s until something inside breaks you out... foreach(var i in 0.Every(5)) { if (someCondition) { break; } ... } Yes, those are kinda play functions and not particularly useful, but they show some of the power of generators and extension methods to form a fluid interface. So what do you think? What are some of your favorite generators and iterators?

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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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Chrome and Firefox not able to find some sites after Ubuntu's recent update?

- by gkr

Loading of revision3.com in Chrome stops and status saying "waiting for static.inplay.tubemogul.com" grooveshark.com in Chrome never loads But wikipedia.org, google.com works just normal same behavior in Firefox too. I use wired DSL connection in Ubuntu 12.04. I guess this started happening after I upgraded the Chrome browser or Flash plugin few days ago from Ubuntu updates through update-manager. Thanks EDIT: Everything works normal in my WinXP. Problem is only in Ubuntu 12.04. This is what I get when I use wget gkr@gkr-desktop:~$ wget revision3.com --2012-06-12 08:58:01-- http://revision3.com/ Resolving revision3.com (revision3.com)... 173.192.117.198 Connecting to revision3.com (revision3.com)|173.192.117.198|:80... connected. HTTP request sent, awaiting response... 200 OK Length: unspecified [text/html] Saving to: `index.html' [ ] 81,046 32.0K/s in 2.5s 2012-06-12 08:58:04 (32.0 KB/s) - `index.html' saved [81046] gkr@gkr-desktop:~$ wget static.inplay.tubemogul.com --2012-06-12 08:51:25-- http://static.inplay.tubemogul.com/ Resolving static.inplay.tubemogul.com (static.inplay.tubemogul.com)... 72.21.81.253 Connecting to static.inplay.tubemogul.com (static.inplay.tubemogul.com)|72.21.81.253|:80... connected. HTTP request sent, awaiting response... 404 Not Found 2012-06-12 08:51:25 ERROR 404: Not Found. grooveshark.com nevers responses so I have to Ctrl+C to terminate wget. gkr@gkr-desktop:~$ wget grooveshark.com --2012-06-12 08:51:33-- http://grooveshark.com/ Resolving grooveshark.com (grooveshark.com)... 8.20.213.76 Connecting to grooveshark.com (grooveshark.com)|8.20.213.76|:80... connected. HTTP request sent, awaiting response... ^C gkr@gkr-desktop:~$ This is the apt term.log of updates I mentioned Log started: 2012-06-09 04:51:45 (Reading database ... (Reading database ... 5% (Reading database ... 10% (Reading database ... 15% (Reading database ... 20% (Reading database ... 25% (Reading database ... 30% (Reading database ... 35% (Reading database ... 40% (Reading database ... 45% (Reading database ... 50% (Reading database ... 55% (Reading database ... 60% (Reading database ... 65% (Reading database ... 70% (Reading database ... 75% (Reading database ... 80% (Reading database ... 85% (Reading database ... 90% (Reading database ... 95% (Reading database ... 100% (Reading database ... 161392 files and directories currently installed.) Preparing to replace google-chrome-stable 19.0.1084.52-r138391 (using .../google-chrome-stable_19.0.1084.56-r140965_i386.deb) ... Unpacking replacement google-chrome-stable ... Preparing to replace libpulse0 1:1.1-0ubuntu15 (using .../libpulse0_1%3a1.1-0ubuntu15.1_i386.deb) ... Unpacking replacement libpulse0 ... Preparing to replace libpulse-mainloop-glib0 1:1.1-0ubuntu15 (using .../libpulse-mainloop-glib0_1%3a1.1-0ubuntu15.1_i386.deb) ... Unpacking replacement libpulse-mainloop-glib0 ... Preparing to replace libpulsedsp 1:1.1-0ubuntu15 (using .../libpulsedsp_1%3a1.1-0ubuntu15.1_i386.deb) ... Unpacking replacement libpulsedsp ... Preparing to replace sudo 1.8.3p1-1ubuntu3.2 (using .../sudo_1.8.3p1-1ubuntu3.3_i386.deb) ... Unpacking replacement sudo ... Preparing to replace flashplugin-installer 11.2.202.235ubuntu0.12.04.1 (using .../flashplugin-installer_11.2.202.236ubuntu0.12.04.1_i386.deb) ... Unpacking replacement flashplugin-installer ... Preparing to replace pulseaudio-utils 1:1.1-0ubuntu15 (using .../pulseaudio-utils_1%3a1.1-0ubuntu15.1_i386.deb) ... Unpacking replacement pulseaudio-utils ... Preparing to replace pulseaudio 1:1.1-0ubuntu15 (using .../pulseaudio_1%3a1.1-0ubuntu15.1_i386.deb) ... Unpacking replacement pulseaudio ... Preparing to replace pulseaudio-module-gconf 1:1.1-0ubuntu15 (using .../pulseaudio-module-gconf_1%3a1.1-0ubuntu15.1_i386.deb) ... Unpacking replacement pulseaudio-module-gconf ... Preparing to replace pulseaudio-module-x11 1:1.1-0ubuntu15 (using .../pulseaudio-module-x11_1%3a1.1-0ubuntu15.1_i386.deb) ... Unpacking replacement pulseaudio-module-x11 ... Preparing to replace shared-mime-info 1.0-0ubuntu4 (using .../shared-mime-info_1.0-0ubuntu4.1_i386.deb) ... Unpacking replacement shared-mime-info ... Preparing to replace pulseaudio-module-bluetooth 1:1.1-0ubuntu15 (using .../pulseaudio-module-bluetooth_1%3a1.1-0ubuntu15.1_i386.deb) ... Unpacking replacement pulseaudio-module-bluetooth ... Processing triggers for menu ... /usr/share/menu/downverter.menu: 1: /usr/share/menu/downverter.menu: Syntax error: word unexpected (expecting ")") Processing triggers for man-db ... locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... Processing triggers for desktop-file-utils ... Processing triggers for gnome-menus ... Processing triggers for ureadahead ... ureadahead will be reprofiled on next reboot Processing triggers for update-notifier-common ... flashplugin-installer: downloading http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_11.2.202.236.orig.tar.gz Installing from local file /tmp/tmpNrBt4g.gz Flash Plugin installed. Processing triggers for doc-base ... Processing 1 changed doc-base file... Registering documents with scrollkeeper... Setting up google-chrome-stable (19.0.1084.56-r140965) ... Setting up libpulse0 (1:1.1-0ubuntu15.1) ... Setting up libpulse-mainloop-glib0 (1:1.1-0ubuntu15.1) ... Setting up libpulsedsp (1:1.1-0ubuntu15.1) ... Setting up sudo (1.8.3p1-1ubuntu3.3) ... Installing new version of config file /etc/pam.d/sudo ... Setting up flashplugin-installer (11.2.202.236ubuntu0.12.04.1) ... locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Setting up pulseaudio-utils (1:1.1-0ubuntu15.1) ... Setting up pulseaudio (1:1.1-0ubuntu15.1) ... Setting up pulseaudio-module-gconf (1:1.1-0ubuntu15.1) ... Setting up pulseaudio-module-x11 (1:1.1-0ubuntu15.1) ... Setting up shared-mime-info (1.0-0ubuntu4.1) ... Setting up pulseaudio-module-bluetooth (1:1.1-0ubuntu15.1) ... Processing triggers for menu ... /usr/share/menu/downverter.menu: 1: /usr/share/menu/downverter.menu: Syntax error: word unexpected (expecting ")") Processing triggers for libc-bin ... ldconfig deferred processing now taking place Log ended: 2012-06-09 04:53:32 This is from history.log Start-Date: 2012-06-09 04:51:45 Commandline: aptdaemon role='role-commit-packages' sender=':1.56' Upgrade: shared-mime-info:i386 (1.0-0ubuntu4, 1.0-0ubuntu4.1), pulseaudio:i386 (1.1-0ubuntu15, 1.1-0ubuntu15.1), libpulse-mainloop-glib0:i386 (1.1-0ubuntu15, 1.1-0ubuntu15.1), sudo:i386 (1.8.3p1-1ubuntu3.2, 1.8.3p1-1ubuntu3.3), pulseaudio-module-bluetooth:i386 (1.1-0ubuntu15, 1.1-0ubuntu15.1), pulseaudio-module-x11:i386 (1.1-0ubuntu15, 1.1-0ubuntu15.1), flashplugin-installer:i386 (11.2.202.235ubuntu0.12.04.1, 11.2.202.236ubuntu0.12.04.1), pulseaudio-utils:i386 (1.1-0ubuntu15, 1.1-0ubuntu15.1), pulseaudio-module-gconf:i386 (1.1-0ubuntu15, 1.1-0ubuntu15.1), libpulse0:i386 (1.1-0ubuntu15, 1.1-0ubuntu15.1), libpulsedsp:i386 (1.1-0ubuntu15, 1.1-0ubuntu15.1), google-chrome-stable:i386 (19.0.1084.52-r138391, 19.0.1084.56-r140965) End-Date: 2012-06-09 04:53:32

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Hosting and consuming WCF services without configuration files

- by martinsj

In this post, I'll demonstrate how to configure both the host and the client in code without the need for configuring services i the <system.serviceModel> section of the config-file. In fact, you don't need a <system.serviceModel> section at all. What you'll do need (and want) sometimes, is the Uri of the service in the configuration file. Configuring the Uri of the the service is actually only needed for the client or when self-hosting, not when hosting in IIS. So, exactly What do we need to configure? The binding type and the binding constraints The metadata behavior Debug behavior You can of course configure even more, and even more if you want to, WCF is after all the king of configuration… As an example I'll be hosting and consuming a service that removes most of the default constraints for WCF-services, using a BasicHttpBinding. Of course, in regards to security, it is probably better to have some constraints on the server, but this is only a demonstration. The ServerConfig class in the code beneath is a static helper class that will be used in the examples. In this post, I’ll be using this helper-class for all configuration, for both the server and the client. In WCF, the client and the server have both their own WCF-configuration. With this piece of code, they will be sharing the same configuration. 1: public static class ServiceConfig 2: { 3: public static Binding DefaultBinding 4: { 5: get 6: { 7: var binding = new BasicHttpBinding(); 8: Configure(binding); 9: return binding; 10: } 11: } 12: 13: public static void Configure(HttpBindingBase binding) 14: { 15: if (binding == null) 16: { 17: throw new ArgumentException("Argument 'binding' cannot be null. Cannot configure binding."); 18: } 19: 20: binding.SendTimeout = new TimeSpan(0, 0, 30, 0); // 30 minute timeout 21: binding.MaxBufferSize = Int32.MaxValue; 22: binding.MaxBufferPoolSize = 2147483647; 23: binding.MaxReceivedMessageSize = Int32.MaxValue; 24: binding.ReaderQuotas.MaxArrayLength = Int32.MaxValue; 25: binding.ReaderQuotas.MaxBytesPerRead = Int32.MaxValue; 26: binding.ReaderQuotas.MaxDepth = Int32.MaxValue; 27: binding.ReaderQuotas.MaxNameTableCharCount = Int32.MaxValue; 28: binding.ReaderQuotas.MaxStringContentLength = Int32.MaxValue; 29: } 30: 31: public static ServiceMetadataBehavior ServiceMetadataBehavior 32: { 33: get 34: { 35: return new ServiceMetadataBehavior 36: { 37: HttpGetEnabled = true, 38: MetadataExporter = {PolicyVersion = PolicyVersion.Policy15} 39: }; 40: } 41: } 42: 43: public static ServiceDebugBehavior ServiceDebugBehavior 44: { 45: get 46: { 47: var smb = new ServiceDebugBehavior(); 48: Configure(smb); 49: return smb; 50: } 51: } 52: 53: 54: public static void Configure(ServiceDebugBehavior behavior) 55: { 56: if (behavior == null) 57: { 58: throw new ArgumentException("Argument 'behavior' cannot be null. Cannot configure debug behavior."); 59: } 60: 61: behavior.IncludeExceptionDetailInFaults = true; 62: } 63: } Configuring the server There are basically two ways to host a WCF service, in IIS and self-hosting. When hosting a WCF service in a production environment using SOA architecture, you'll be most likely hosting it in IIS. When testing the service in integration tests, it's very handy to be able to self-host services in the unit-tests. In fact, you can share the the WCF configuration for self-hosted services and services hosted in IIS. And that is exactly what you want to do, testing the same configurations for test and production environments. Configuring when Self-hosting When self-hosting, in order to start the service, you'll have to instantiate the ServiceHost class, configure the service and open it. 1: // Create the service-host. 2: var host = new ServiceHost(typeof(MyService), endpoint); 3: 4: // Configure the binding 5: host.AddServiceEndpoint(typeof(IMyService), ServiceConfig.DefaultBinding, endpoint); 6: 7: // Configure metadata behavior 8: host.Description.Behaviors.Add(ServiceConfig.ServiceMetadataBehavior); 9: 10: // Configure debgug behavior 11: ServiceConfig.Configure((ServiceDebugBehavior)host.Description.Behaviors[typeof(ServiceDebugBehavior)]); 12: 13: // Start listening to the service 14: host.Open(); 15: Configuring when hosting in IIS When you create a WCF service application with the wizard in Visual Studio, you'll end up with bits and pieces of code in order to get the service running: Svc-file with codebehind. A interface to the service Web.config In order to get rid of the configuration in the <system.serviceModel> section, which the wizard has generated for us, we must tell the service that we have a factory that will create the service for us. We do this by changing the markup for the svc-file: 1: <%@ ServiceHost Language="C#" Debug="true" Service="Namespace.MyService" Factory="Namespace.ServiceHostFactory" %> The markup tells IIS that we have a factory called ServiceHostFactory for this service. The service factory has a method we can override which will be called when someone asks IIS for the service. There are overloads we can override: 1: System.ServiceModel.ServiceHostBase CreateServiceHost(string constructorString, Uri[] baseAddresses) 2: System.ServiceModel.ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses) 3: In this example, we'll be using the last one, so our implementation looks like this: 1: public class ServiceHostFactory : System.ServiceModel.Activation.ServiceHostFactory 2: { 3: 4: protected override System.ServiceModel.ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses) 5: { 6: var host = base.CreateServiceHost(serviceType, baseAddresses); 7: host.Description.Behaviors.Add(ServiceConfig.ServiceMetadataBehavior); 8: ServiceConfig.Configure((ServiceDebugBehavior)host.Description.Behaviors[typeof(ServiceDebugBehavior)]); 9: return host; 10: } 11: } 12: 1: public class ServiceHostFactory : System.ServiceModel.Activation.ServiceHostFactory 2: { 3: 4: protected override System.ServiceModel.ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses) 5: { 6: var host = base.CreateServiceHost(serviceType, baseAddresses); 7: host.Description.Behaviors.Add(ServiceConfig.ServiceMetadataBehavior); 8: ServiceConfig.Configure((ServiceDebugBehavior)host.Description.Behaviors[typeof(ServiceDebugBehavior)]); 9: return host; 10: } 11: } 12: As you can see, we are using the same configuration helper we used when self-hosting. Now, when you have a factory, the <system.serviceModel> section of the configuration can be removed, because the section will be ignored when the service has a custom factory. If you want to configure something else in the config-file, one could configure in some other section. Configuring the client Microsoft has helpfully created a ChannelFactory class in order to create a proxy client. When using this approach, you don't have generate those awfull proxy classes for the client. If you share the contracts with the server in it's own assembly like in the layer diagram under, you can share the same piece of code. The contracts in WCF are the interface to the service and if any, the datacontracts (custom types) the service depends on. Using the ChannelFactory with our configuration helper-class is very simple: 1: var identity = EndpointIdentity.CreateDnsIdentity("localhost"); 2: var endpointAddress = new EndpointAddress(endPoint, identity); 3: var factory = new ChannelFactory<IMyService>(DeployServiceConfig.DefaultBinding, endpointAddress); 4: using (var myService = new factory.CreateChannel()) 5: { 6: myService.Hello(); 7: } 8: factory.Close(); Happy configuration!

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Lambda’s for .NET made easy…

- by mbcrump

The purpose of my blog is to explain things for a beginner to intermediate c# programmer. I’ve seen several blog post that use lambda expressions always assuming the audience is familiar with them. The purpose of this post is to make them simple and easily understood. Let’s begin with a definition. A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types. So anonymous function… delegates or expression tree types? I don’t get it??? Confused yet? Lets break this into a few definitions and jump right into the code. anonymous function – is an "inline" statement or expression that can be used wherever a delegate type is expected. delegate - is a type that references a method. Once a delegate is assigned a method, it behaves exactly like that method. The delegate method can be used like any other method, with parameters and a return value. Expression trees - represent code in a tree-like data structure, where each node is an expression, for example, a method call or a binary operation such as x < y. Don’t worry if this still sounds confusing, lets jump right into the code with a simple 3 line program. We are going to use a Function Delegate (all you need to remember is that this delegate returns a value.) Lambda expressions are used most commonly with the Func and Action delegates, so you will see an example of both of these. Lambda Expression 3 lines. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { Func<int, int> myfunc = x => x *x; Console.WriteLine(myfunc(6).ToString()); Console.ReadLine(); } } } Is equivalent to Old way of doing it. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { Console.WriteLine(myFunc(6).ToString()); Console.ReadLine(); } static int myFunc(int x) { return x * x; } } } In the example, there is a single parameter, x, and the expression is x*x. I’m going to stop here to make sure you are still with me. A lambda expression is an unnamed method written in place of a delegate instance. In other words, the compiler converts the lambda expression to either a : A delegate instance An expression tree All lambda have the following form: (parameters) => expression or statement block Now look back to the ones we have created. It should start to sink in. Don’t get stuck on the => form, use it as an identifier of a lambda. A Lamba expression can also be written in the following form: Lambda Expression. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { Func<int, int> myFunc = x => { return x * x; }; Console.WriteLine(myFunc(6).ToString()); Console.ReadLine(); } } } This form may be easier to read but consumes more space. Lets try an Action delegate – this delegate does not return a value. Action Delegate example. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { Action<string> myAction = (string x) => { Console.WriteLine(x); }; myAction("michael has made this so easy"); Console.ReadLine(); } } } Lambdas can also capture outer variables (such as the example below) A lambda expression can reference the local variables and parameters of the method in which it’s defined. Outer variables referenced by a lambda expression are called captured variables. Capturing Outer Variables using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { string mike = "Michael"; Action<string> myAction = (string x) => { Console.WriteLine("{0}{1}", mike, x); }; myAction(" has made this so easy"); Console.ReadLine(); } } } Lamba’s can also with a strongly typed list to loop through a collection. Used w a strongly typed list. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { List<string> list = new List<string>() { "1", "2", "3", "4" }; list.ForEach(s => Console.WriteLine(s)); Console.ReadLine(); } } } Outputs: 1 2 3 4 I think this will get you started with Lambda’s, as always consult the MSDN documentation for more information. Still confused? Hopefully you are not.

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Bluetooth connection. Problem with sony ericsson.

- by Hugi

I have bt client and server. Then i use method Connector.open, client connects to the port, but passed so that my server does not see them. Nokia for all normal, but with sony ericsson i have this problem. On bt adapter open one port (com 5). Listings Client /* * To change this template, choose Tools | Templates * and open the template in the editor. */ import java.util.Vector; import javax.bluetooth.*; import javax.microedition.midlet.*; import javax.microedition.lcdui.*; import javax.microedition.io.*; import java.io.*; /** * @author ????????????? */ public class Client extends MIDlet implements DiscoveryListener, CommandListener { private static Object lock=new Object(); private static Vector vecDevices=new Vector(); private ServiceRecord[] servRec = new ServiceRecord[INQUIRY_COMPLETED]; private Form form = new Form( "Search" ); private List voteList = new List( "Vote list", List.IMPLICIT ); private List vote = new List( "", List.EXCLUSIVE ); private RemoteDevice remoteDevice; private String connectionURL = null; protected int stopToken = 255; private Command select = null; public void startApp() { //view form Display.getDisplay(this).setCurrent(form); try { //device search print("Starting device inquiry..."); getAgent().startInquiry(DiscoveryAgent.GIAC, this); try { synchronized(lock){ lock.wait(); } }catch (InterruptedException e) { e.printStackTrace(); } //device count int deviceCount=vecDevices.size(); if(deviceCount <= 0) { print("No Devices Found ."); } else{ remoteDevice=(RemoteDevice)vecDevices.elementAt(0); print( "Server found" ); //create uuid UUID uuid = new UUID(0x1101); UUID uuids[] = new UUID[] { uuid }; //search service print( "Searching for service..." ); getAgent().searchServices(null,uuids,remoteDevice,this); } } catch( Exception e) { e.printStackTrace(); } } //if deivce discovered add to vecDevices public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) { //add the device to the vector try { if(!vecDevices.contains(btDevice) && btDevice.getFriendlyName(true).equals("serverHugi")){ vecDevices.addElement(btDevice); } } catch( IOException e ) { } } public synchronized void servicesDiscovered(int transID, ServiceRecord[] servRecord) { //for each service create connection if( servRecord!=null && servRecord.length>0 ){ print( "Service found" ); connectionURL = servRecord[0].getConnectionURL(ServiceRecord.NOAUTHENTICATE_NOENCRYPT,false); //connectionURL = servRecord[0].getConnectionURL(ServiceRecord.AUTHENTICATE_NOENCRYPT,false); } if ( connectionURL != null ) { showVoteList(); } } public void serviceSearchCompleted(int transID, int respCode) { //print( "serviceSearchCompleted" ); synchronized(lock){ lock.notify(); } } //This callback method will be called when the device discovery is completed. public void inquiryCompleted(int discType) { synchronized(lock){ lock.notify(); } switch (discType) { case DiscoveryListener.INQUIRY_COMPLETED : print("INQUIRY_COMPLETED"); break; case DiscoveryListener.INQUIRY_TERMINATED : print("INQUIRY_TERMINATED"); break; case DiscoveryListener.INQUIRY_ERROR : print("INQUIRY_ERROR"); break; default : print("Unknown Response Code"); break; } } //add message at form public void print( String msg ) { form.append( msg ); form.append( "\n\n" ); } public void pauseApp() { } public void destroyApp(boolean unconditional) { } //get agent :))) private DiscoveryAgent getAgent() { try { return LocalDevice.getLocalDevice().getDiscoveryAgent(); } catch (BluetoothStateException e) { throw new Error(e.getMessage()); } } private synchronized String getMessage( final String send ) { StreamConnection stream = null; DataInputStream in = null; DataOutputStream out = null; String r = null; try { //open connection stream = (StreamConnection) Connector.open(connectionURL); in = stream.openDataInputStream(); out = stream.openDataOutputStream(); out.writeUTF( send ); out.flush(); r = in.readUTF(); print( r ); in.close(); out.close(); stream.close(); return r; } catch (IOException e) { } finally { if (stream != null) { try { stream.close(); } catch (IOException e) { } } return r; } } private synchronized void showVoteList() { String votes = getMessage( "c_getVotes" ); voteList.append( votes, null ); select = new Command( "Select", Command.OK, 4 ); voteList.addCommand( select ); voteList.setCommandListener( this ); Display.getDisplay(this).setCurrent(voteList); } private synchronized void showVote( int index ) { String title = getMessage( "c_getVote_"+index ); vote.setTitle( title ); vote.append( "Yes", null ); vote.append( "No", null ); vote.setCommandListener( this ); Display.getDisplay(this).setCurrent(vote); } public void commandAction( Command c, Displayable d ) { if ( c == select && d == voteList ) { int index = voteList.getSelectedIndex(); print( ""+index ); showVote( index ); } } } Use BlueCove in this program. Server /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package javaapplication4; import java.io.*; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; import javax.bluetooth.*; import javax.microedition.io.*; import javaapplication4.Connect; /** * * @author ????????????? */ public class SampleSPPServer { protected static int endToken = 255; private static Lock lock=new ReentrantLock(); private static StreamConnection conn = null; private static StreamConnectionNotifier streamConnNotifier = null; private void startServer() throws IOException{ //Create a UUID for SPP UUID uuid = new UUID("1101", true); //Create the service url String connectionString = "btspp://localhost:" + uuid +";name=Sample SPP Server"; //open server url StreamConnectionNotifier streamConnNotifier = (StreamConnectionNotifier)Connector.open( connectionString ); while ( true ) { Connect ct = new Connect( streamConnNotifier.acceptAndOpen() ); ct.getMessage(); } } /** * @param args the command line arguments */ public static void main(String[] args) { //display local device address and name try { LocalDevice localDevice = LocalDevice.getLocalDevice(); localDevice.setDiscoverable(DiscoveryAgent.GIAC); System.out.println("Name: "+localDevice.getFriendlyName()); } catch( Throwable e ) { e.printStackTrace(); } SampleSPPServer sampleSPPServer=new SampleSPPServer(); try { //start server sampleSPPServer.startServer(); } catch( IOException e ) { e.printStackTrace(); } } } Connect /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package javaapplication4; import java.io.*; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; import javax.bluetooth.*; import javax.microedition.io.*; /** * * @author ????????????? */ public class Connect { private static DataInputStream in = null; private static DataOutputStream out = null; private static StreamConnection connection = null; private static Lock lock=new ReentrantLock(); public Connect( StreamConnection conn ) { connection = conn; } public synchronized void getMessage( ) { Thread t = new Thread() { public void run() { try { in = connection.openDataInputStream(); out = connection.openDataOutputStream(); String r = in.readUTF(); System.out.println("read:" + r); if ( r.equals( "c_getVotes" ) ) { out.writeUTF( "vote1" ); out.flush(); } if ( r.equals( "c_getVote_0" ) ) { out.writeUTF( "Vote1" ); out.flush(); } out.close(); in.close(); } catch (Throwable e) { } finally { if (in != null) { try { in.close(); } catch (IOException e) { } } try { connection.close(); } catch( IOException e ) { } } } }; t.start(); } }

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png image store in database and retrieve in android 1.5

- by hany

hai, I am new to android. I have problem. This is my code but it will not work, the problem is in view binder. Please correct it. // this is my activity package com.android.Fruits2; import java.util.ArrayList; import java.util.HashMap; import android.app.ListActivity; import android.database.Cursor; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.widget.SimpleAdapter; import android.widget.SimpleCursorAdapter; import android.widget.SimpleAdapter.ViewBinder; public class Fruits2 extends ListActivity { private DBhelper mDB; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // setContentView(R.layout.main); mDB = new DBhelper(this); mDB.Reset(); Bitmap img = BitmapFactory.decodeResource(getResources(), R.drawable.icon); mDB.createPersonEntry(new PersonData(img, "Harsha", 24,"mca")); String[] columns = {mDB.KEY_ID, mDB.KEY_IMG, mDB.KEY_NAME, mDB.KEY_AGE, mDB.KEY_STUDY}; String table = mDB.PERSON_TABLE; Cursor c = mDB.getHandle().query(table, columns, null, null, null, null, null); startManagingCursor(c); SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.data, c, new String[] {mDB.KEY_IMG, mDB.KEY_NAME, mDB.KEY_AGE, mDB.KEY_STUDY}, new int[] {R.id.img, R.id.name, R.id.age,R.id.study}); adapter.setViewBinder( new MyViewBinder()); setListAdapter(adapter); } } //my viewbinder package com.android.Fruits2; import android.database.Cursor; import android.graphics.BitmapFactory; import android.view.View; import android.widget.ImageView; import android.widget.SimpleCursorAdapter; public class MyViewBinder implements SimpleCursorAdapter.ViewBinder { public boolean setViewValue(View view, Cursor cursor, int columnIndex) { if( (view instanceof ImageView) ) { ImageView iv = (ImageView) view; byte[] img = cursor.getBlob(columnIndex); iv.setImageBitmap(BitmapFactory.decodeByteArray(img, 0, img.length)); return true; } return false; } } // data package com.android.Fruits2; import android.graphics.Bitmap; public class PersonData { private Bitmap bmp; private String name; private int age; private String study; public PersonData(Bitmap b, String n, int k, String v) { bmp = b; name = n; age = k; study = v; } public Bitmap getBitmap() { return bmp; } public String getName() { return name; } public int getAge() { return age; } public String getStudy() { return study; } } //dbhelper package com.android.Fruits2; import java.io.ByteArrayOutputStream; import android.content.ContentValues; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.graphics.Bitmap; import android.provider.BaseColumns; public class DBhelper { public static final String KEY_ID = BaseColumns._ID; public static final String KEY_NAME = "name"; public static final String KEY_AGE = "age"; public static final String KEY_STUDY = "study"; public static final String KEY_IMG = "image"; private DatabaseHelper mDbHelper; private SQLiteDatabase mDb; private static final String DATABASE_NAME = "PersonalDB"; private static final int DATABASE_VERSION = 1; public static final String PERSON_TABLE = "Person"; private static final String CREATE_PERSON_TABLE = "create table "+PERSON_TABLE+" (" +KEY_ID+" integer primary key autoincrement, " +KEY_IMG+" blob not null, " +KEY_NAME+" text not null , " +KEY_AGE+" integer not null, " +KEY_STUDY+" text not null);"; private final Context mCtx; private boolean opened = false; private static class DatabaseHelper extends SQLiteOpenHelper { DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } public void onCreate(SQLiteDatabase db) { db.execSQL(CREATE_PERSON_TABLE); } public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { db.execSQL("DROP TABLE IF EXISTS "+PERSON_TABLE); onCreate(db); } } public void Reset() { openDB(); mDbHelper.onUpgrade(this.mDb, 1, 1); closeDB(); } public DBhelper(Context ctx) { mCtx = ctx; mDbHelper = new DatabaseHelper(mCtx); } private SQLiteDatabase openDB() { if(!opened) mDb = mDbHelper.getWritableDatabase(); opened = true; return mDb; } public SQLiteDatabase getHandle() { return openDB(); } private void closeDB() { if(opened) mDbHelper.close(); opened = false; } public void createPersonEntry(PersonData about) { openDB(); ByteArrayOutputStream out = new ByteArrayOutputStream(); about.getBitmap().compress(Bitmap.CompressFormat.PNG, 100, out); ContentValues cv = new ContentValues(); cv.put(KEY_IMG, out.toByteArray()); cv.put(KEY_NAME, about.getName()); cv.put(KEY_AGE, about.getAge()); cv.put(KEY_STUDY, about.getStudy()); mDb.insert(PERSON_TABLE, null, cv); closeDB(); } } //data.xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="wrap_content"> <ImageView android:id = "@+id/img" android:layout_width = "wrap_content" android:layout_height = "wrap_content" > </ImageView> <TextView android:id = "@+id/name" android:layout_width = "wrap_content" android:layout_height = "wrap_content" android:textSize="15dp" android:textColor="#ff0000" > </TextView> <TextView android:id = "@+id/age" android:layout_width = "wrap_content" android:layout_height = "wrap_content" android:textSize="15dp" android:textColor="#ff0000" /> <TextView android:id = "@+id/study" android:layout_width = "wrap_content" android:layout_height = "wrap_content" android:textSize="15dp" android:textColor="#ff0000" /> </LinearLayout> When I run this in android 1.6 and 2.1, it works. But when I run in android 1.5, not work. My application is android 1.5. Please correct and send code to me. Thank you.

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how to version minder for web application data

- by dankyy1

hi all;I'm devoloping a web application which renders data from DB and also updates datas with editor UI Pages.So i want to implement a versioning mechanism for render pages got data over db again if only data on db updated by editor pages.. I decided to use Session objects for the version information that client had taken latestly.And the Application object that the latest DB version of objects ,i used the data objects guid as key for each data item client version holder class like below ItemRunnigVersionInformation class holds currentitem guid and last loadtime from DB public class ClientVersionManager { public static List<ItemRunnigVersionInformation> SessionItemRunnigVersionInformation { get { if (HttpContext.Current.Session["SessionItemRunnigVersionInformation"] == null) HttpContext.Current.Session["SessionItemRunnigVersionInformation"] = new List<ItemRunnigVersionInformation>(); return (List<ItemRunnigVersionInformation>)HttpContext.Current.Session["SessionItemRunnigVersionInformation"]; } set { HttpContext.Current.Session["SessionItemRunnigVersionInformation"] = value; } } /// <summary> /// this will be updated when editor pages /// </summary> /// <param name="itemRunnigVersionInformation"></param> public static void UpdateItemRunnigSessionVersion(string itemGuid) { ItemRunnigVersionInformation itemRunnigVersionAtAppDomain = PlayListVersionManager.GetItemRunnigVersionInformationByID(itemGuid); ItemRunnigVersionInformation itemRunnigVersionInformationAtSession = SessionItemRunnigVersionInformation.FirstOrDefault(t => t.ItemGuid == itemGuid); if ((itemRunnigVersionInformationAtSession == null) && (itemRunnigVersionAtAppDomain != null)) { ExtensionMethodsForClientVersionManager.ExtensionMethodsForClientVersionManager.Add(SessionItemRunnigVersionInformation, itemRunnigVersionAtAppDomain); } else if (itemRunnigVersionAtAppDomain != null) { ExtensionMethodsForClientVersionManager.ExtensionMethodsForClientVersionManager.Remove(SessionItemRunnigVersionInformation, itemRunnigVersionInformationAtSession); ExtensionMethodsForClientVersionManager.ExtensionMethodsForClientVersionManager.Add(SessionItemRunnigVersionInformation, itemRunnigVersionAtAppDomain); } } /// <summary> /// by given parameters check versions over PlayListVersionManager versions and /// adds versions to clientversion manager if any item version on /// playlist not found it will also added to PlaylistManager list /// </summary> /// <param name="playList"></param> /// <param name="userGuid"></param> /// <param name="ownerGuid"></param> public static void UpdateCurrentSessionVersion(PlayList playList, string userGuid, string ownerGuid) { ItemRunnigVersionInformation tmpItemRunnigVersionInformation; List<ItemRunnigVersionInformation> currentItemRunnigVersionInformationList = new List<ItemRunnigVersionInformation>(); if (!string.IsNullOrEmpty(userGuid)) { tmpItemRunnigVersionInformation = PlayListVersionManager.GetItemRunnigVersionInformationByID(userGuid); if (tmpItemRunnigVersionInformation == null) { tmpItemRunnigVersionInformation = new ItemRunnigVersionInformation(userGuid, DateTime.Now.ToUniversalTime()); PlayListVersionManager.UpdateItemRunnigAppDomainVersion(tmpItemRunnigVersionInformation); } ExtensionMethodsForClientVersionManager.ExtensionMethodsForClientVersionManager.Add(currentItemRunnigVersionInformationList, tmpItemRunnigVersionInformation); } if (!string.IsNullOrEmpty(ownerGuid)) { tmpItemRunnigVersionInformation = PlayListVersionManager.GetItemRunnigVersionInformationByID(ownerGuid); if (tmpItemRunnigVersionInformation == null) { tmpItemRunnigVersionInformation = new ItemRunnigVersionInformation(ownerGuid, DateTime.Now.ToUniversalTime()); PlayListVersionManager.UpdateItemRunnigAppDomainVersion(tmpItemRunnigVersionInformation); } ExtensionMethodsForClientVersionManager.ExtensionMethodsForClientVersionManager.Add(currentItemRunnigVersionInformationList, tmpItemRunnigVersionInformation); } if ((playList != null) && (playList.PlayListItemCollection != null)) { tmpItemRunnigVersionInformation = PlayListVersionManager.GetItemRunnigVersionInformationByID(playList.GUID); if (tmpItemRunnigVersionInformation == null) { tmpItemRunnigVersionInformation = new ItemRunnigVersionInformation(playList.GUID, DateTime.Now.ToUniversalTime()); PlayListVersionManager.UpdateItemRunnigAppDomainVersion(tmpItemRunnigVersionInformation); } currentItemRunnigVersionInformationList.Add(tmpItemRunnigVersionInformation); foreach (PlayListItem playListItem in playList.PlayListItemCollection) { tmpItemRunnigVersionInformation = PlayListVersionManager.GetItemRunnigVersionInformationByID(playListItem.GUID); if (tmpItemRunnigVersionInformation == null) { tmpItemRunnigVersionInformation = new ItemRunnigVersionInformation(playListItem.GUID, DateTime.Now.ToUniversalTime()); PlayListVersionManager.UpdateItemRunnigAppDomainVersion(tmpItemRunnigVersionInformation); } currentItemRunnigVersionInformationList.Add(tmpItemRunnigVersionInformation); foreach (SoftKey softKey in playListItem.PlayListSoftKeys) { tmpItemRunnigVersionInformation = PlayListVersionManager.GetItemRunnigVersionInformationByID(softKey.GUID); if (tmpItemRunnigVersionInformation == null) { tmpItemRunnigVersionInformation = new ItemRunnigVersionInformation(softKey.GUID, DateTime.Now.ToUniversalTime()); PlayListVersionManager.UpdateItemRunnigAppDomainVersion(tmpItemRunnigVersionInformation); } ExtensionMethodsForClientVersionManager.ExtensionMethodsForClientVersionManager.Add(currentItemRunnigVersionInformationList, tmpItemRunnigVersionInformation); } foreach (MenuItem menuItem in playListItem.MenuItems) { tmpItemRunnigVersionInformation = PlayListVersionManager.GetItemRunnigVersionInformationByID(menuItem.Guid); if (tmpItemRunnigVersionInformation == null) { tmpItemRunnigVersionInformation = new ItemRunnigVersionInformation(menuItem.Guid, DateTime.Now.ToUniversalTime()); PlayListVersionManager.UpdateItemRunnigAppDomainVersion(tmpItemRunnigVersionInformation); } ExtensionMethodsForClientVersionManager.ExtensionMethodsForClientVersionManager.Add(currentItemRunnigVersionInformationList, tmpItemRunnigVersionInformation); } } } SessionItemRunnigVersionInformation = currentItemRunnigVersionInformationList; } public static ItemRunnigVersionInformation GetItemRunnigVersionInformationById(string itemGuid) { return SessionItemRunnigVersionInformation.FirstOrDefault(t => t.ItemGuid == itemGuid); } public static void DeleteItemRunnigAppDomain(string itemGuid) { ExtensionMethodsForClientVersionManager.ExtensionMethodsForClientVersionManager.Remove(SessionItemRunnigVersionInformation, NG.IPTOffice.Paloma.Helper.ExtensionMethodsFoPlayListVersionManager.ExtensionMethodsFoPlayListVersionManager.GetMatchingItemRunnigVersionInformation(SessionItemRunnigVersionInformation, itemGuid)); } } and that was for server one public class PlayListVersionManager { public static List<ItemRunnigVersionInformation> AppDomainItemRunnigVersionInformation { get { if (HttpContext.Current.Application["AppDomainItemRunnigVersionInformation"] == null) HttpContext.Current.Application["AppDomainItemRunnigVersionInformation"] = new List<ItemRunnigVersionInformation>(); return (List<ItemRunnigVersionInformation>)HttpContext.Current.Application["AppDomainItemRunnigVersionInformation"]; } set { HttpContext.Current.Application["AppDomainItemRunnigVersionInformation"] = value; } } public static ItemRunnigVersionInformation GetItemRunnigVersionInformationByID(string itemGuid) { return ExtensionMethodsFoPlayListVersionManager.ExtensionMethodsFoPlayListVersionManager.GetMatchingItemRunnigVersionInformation(AppDomainItemRunnigVersionInformation, itemGuid); } /// <summary> /// this will be updated when editor pages /// if any record at playlistversion is found it will be addedd /// </summary> /// <param name="itemRunnigVersionInformation"></param> public static void UpdateItemRunnigAppDomainVersion(ItemRunnigVersionInformation itemRunnigVersionInformation) { ItemRunnigVersionInformation itemRunnigVersionInformationAtAppDomain = NG.IPTOffice.Paloma.Helper.ExtensionMethodsFoPlayListVersionManager.ExtensionMethodsFoPlayListVersionManager.GetMatchingItemRunnigVersionInformation(AppDomainItemRunnigVersionInformation, itemRunnigVersionInformation.ItemGuid); if (itemRunnigVersionInformationAtAppDomain == null) { ExtensionMethodsFoPlayListVersionManager.ExtensionMethodsFoPlayListVersionManager.Add(AppDomainItemRunnigVersionInformation, itemRunnigVersionInformation); } else { ExtensionMethodsFoPlayListVersionManager.ExtensionMethodsFoPlayListVersionManager.Remove(AppDomainItemRunnigVersionInformation, itemRunnigVersionInformationAtAppDomain); ExtensionMethodsFoPlayListVersionManager.ExtensionMethodsFoPlayListVersionManager.Add(AppDomainItemRunnigVersionInformation, itemRunnigVersionInformation); } } //this will be checked each time if needed to update item over DB public static bool IsRunnigItemLastVersion(ItemRunnigVersionInformation itemRunnigVersionInformation, bool ignoreNullEntry, out bool itemNotExistsAtAppDomain) { itemNotExistsAtAppDomain = false; if (itemRunnigVersionInformation != null) { ItemRunnigVersionInformation itemRunnigVersionInformationAtAppDomain = AppDomainItemRunnigVersionInformation.FirstOrDefault(t => t.ItemGuid == itemRunnigVersionInformation.ItemGuid); itemNotExistsAtAppDomain = (itemRunnigVersionInformationAtAppDomain == null); if (itemNotExistsAtAppDomain && (ignoreNullEntry)) { ExtensionMethodsFoPlayListVersionManager.ExtensionMethodsFoPlayListVersionManager.Add(AppDomainItemRunnigVersionInformation, itemRunnigVersionInformation); return true; } else if (!itemNotExistsAtAppDomain && (itemRunnigVersionInformationAtAppDomain.LastLoadTime <= itemRunnigVersionInformation.LastLoadTime)) return true; else return false; } else return ignoreNullEntry; } public static void DeleteItemRunnigAppDomain(string itemGuid) { ExtensionMethodsFoPlayListVersionManager.ExtensionMethodsFoPlayListVersionManager.Remove(AppDomainItemRunnigVersionInformation, NG.IPTOffice.Paloma.Helper.ExtensionMethodsFoPlayListVersionManager.ExtensionMethodsFoPlayListVersionManager.GetMatchingItemRunnigVersionInformation(AppDomainItemRunnigVersionInformation, itemGuid)); } } when more than one client requests the page i got "Collection was modified; enumeration operation may not execute." like below.. xception: System.Web.HttpUnhandledException: Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.InvalidOperationException: Collection was modified; enumeration operation may not execute. at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource) at System.Collections.Generic.List1.Enumerator.MoveNextRare() at System.Collections.Generic.List1.Enumerator.MoveNext() at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable1 source, Func2 predicate) at NG.IPTOffice.Paloma.Helper.PlayListVersionManager.UpdateItemRunnigAppDomainVersion(ItemRunnigVersionInformation itemRunnigVersionInformation) in at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace --- at System.Web.UI.Page.HandleError(Exception e) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest() at System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) at System.Web.UI.Page.ProcessRequest(HttpContext context) at ASP.playlistwebform_aspx.ProcessRequest(HttpContext context) in c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\ipservicestest\8921e5c8\5d09c94d\App_Web_n4qdnfcq.2.cs:line 0 at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)----------- how to implement version management like this scnerio? how can i to avoid this exception? thnx

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How to correctly populate records from SQLlite in ListActivity?

- by Pavel

Hi. Can someone please tell me how can I easily display every record from sqllite in ListActivity tab? I'm kinda confused with this. Do I have to create db from my helper class in TabActivity or ListActivity or both? My db helper class is as follow: package tabs.app; 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 { private static String DB_PATH = "/data/data/tabs.app/databases/"; public static final String KEY_ROWID = "_id"; public static final String KEY_LATITUDE = "latitude"; public static final String KEY_LONGITUDE = "longitude"; private static final String TAG = "DBAdapter"; private static final String DATABASE_NAME = "coords"; private static final String DATABASE_TABLE = "coordsStorages"; private static final int DATABASE_VERSION = 2; /* private static final String DATABASE_CREATE = "create table coordsStorage (_id integer primary key autoincrement, latitude integer not null, longitude integer not null)"; */ public 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("create table coordsStorages (_id integer primary key autoincrement, latitude integer not null, longitude integer not null)"); } @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 insertCoords(int latitude, int longitude) { ContentValues initialValues = new ContentValues(); initialValues.put(KEY_LATITUDE, latitude); initialValues.put(KEY_LONGITUDE, longitude); return db.insert(DATABASE_TABLE, null, initialValues); } public void openDataBase() throws SQLException{ //Open the database String myPath = DB_PATH + DATABASE_NAME; db = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); } //---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_LATITUDE, KEY_LONGITUDE}, 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_LATITUDE, KEY_LONGITUDE}, KEY_ROWID + "=" + rowId, null, null, null, null, null); if (mCursor != null) { mCursor.moveToFirst(); } return mCursor; } //---updates a title--- /*public boolean updateTitle(long rowId, int latitude, int longitude) { ContentValues args = new ContentValues(); args.put(KEY_LATITUDE, latitude); args.put(KEY_LONGITUDE, longitude); return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0; }*/ } And Im trying to retrieve the records in TabActivity like this: public class Areas extends ListActivity { DBAdapter db; SimpleCursorAdapter mAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.areas_layout); db = new DBAdapter(this); db.open(); Cursor c = db.getAllTitles(); startManagingCursor(c); String[] display = new String[] { db.KEY_LATITUDE }; int[] to = new int[] { R.id.row_latitude}; /* String[] display2 = new String[] { db.KEY_LONGITUDE }; int[] to2 = new int[] { R.id.row_longitude};*/ mAdapter = new SimpleCursorAdapter(this, R.layout.areas_layout, c, display, to); setListAdapter(mAdapter); /* mAdapter2 = new SimpleCursorAdapter(this, R.layout.areas_layout, c, display2, to2); setListAdapter(mAdapter2);*/ db.close(); } /* private void fillData() { // Get all of the rows from the database and create the item list Cursor c = db.getAllTitles(); startManagingCursor(c); }*/ } Whenever I'm trying to do that the error log outputs this: 06-07 09:51:56.529: ERROR/AndroidRuntime(2034): Uncaught handler: thread main exiting due to uncaught exception 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): java.lang.RuntimeException: Unable to start activity ComponentInfo{tabs.app/tabs.app.Areas}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list' 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2401) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.app.ActivityThread.startActivityNow(ActivityThread.java:2242) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:631) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.widget.TabHost.setCurrentTab(TabHost.java:317) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.widget.TabHost$2.onTabSelectionChanged(TabHost.java:127) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.widget.TabWidget$TabClickListener.onClick(TabWidget.java:346) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.View.performClick(View.java:2344) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.View.onTouchEvent(View.java:4133) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.View.dispatchTouchEvent(View.java:3672) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:850) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1712) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1202) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.app.Activity.dispatchTouchEvent(Activity.java:1987) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1696) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.view.ViewRoot.handleMessage(ViewRoot.java:1658) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.os.Handler.dispatchMessage(Handler.java:99) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.os.Looper.loop(Looper.java:123) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.app.ActivityThread.main(ActivityThread.java:4203) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at java.lang.reflect.Method.invokeNative(Native Method) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at java.lang.reflect.Method.invoke(Method.java:521) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at dalvik.system.NativeStart.main(Native Method) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list' 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.app.ListActivity.onContentChanged(ListActivity.java:236) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:316) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.app.Activity.setContentView(Activity.java:1620) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at tabs.app.Areas.onCreate(Areas.java:18) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364) 06-07 09:51:56.559: ERROR/AndroidRuntime(2034): ... 30 more 06-07 09:51:56.619: INFO/Process(51): Sending signal. PID: 2034 SIG: 3 06-07 09:51:56.619: INFO/dalvikvm(2034): threadid=7: reacting to signal 3 06-07 09:51:56.619: ERROR/dalvikvm(2034): Unable to open stack trace file '/data/anr/traces.txt': Permission denied Can someone please tell me what I'm doing wrong? Help greatly appreciated!

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Database Tutorial: The method open() is undefined for the type MainActivity.DBAdapter

- by user2203633

I am trying to do this database tutorial on SQLite Eclipse: https://www.youtube.com/watch?v=j-IV87qQ00M But I get a few errors at the end.. at db.ppen(); i get error: The method open() is undefined for the type MainActivity.DBAdapter and similar for insert record and close. MainActivity: package com.example.studentdatabase; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import android.app.Activity; import android.app.ListActivity; import android.content.Intent; import android.database.Cursor; import android.os.Bundle; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.Button; import android.widget.Toast; public class MainActivity extends Activity { /** Called when the activity is first created. */ //DBAdapter db = new DBAdapter(this); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button addBtn = (Button)findViewById(R.id.add); addBtn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent i = new Intent(MainActivity.this, addassignment.class); startActivity(i); } }); try { String destPath = "/data/data/" + getPackageName() + "/databases/AssignmentDB"; File f = new File(destPath); if (!f.exists()) { CopyDB( getBaseContext().getAssets().open("mydb"), new FileOutputStream(destPath)); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } DBAdapter db = new DBAdapter(); //---add an assignment--- db.open(); long id = db.insertRecord("Hello World", "2/18/2012", "DPR 224", "First Android Project"); id = db.insertRecord("Workbook Exercises", "3/1/2012", "MAT 100", "Do odd numbers"); db.close(); //---get all Records--- /* db.open(); Cursor c = db.getAllRecords(); if (c.moveToFirst()) { do { DisplayRecord(c); } while (c.moveToNext()); } db.close(); */ /* //---get a Record--- db.open(); Cursor c = db.getRecord(2); if (c.moveToFirst()) DisplayRecord(c); else Toast.makeText(this, "No Assignments found", Toast.LENGTH_LONG).show(); db.close(); */ //---update Record--- /* db.open(); if (db.updateRecord(1, "Hello Android", "2/19/2012", "DPR 224", "First Android Project")) Toast.makeText(this, "Update successful.", Toast.LENGTH_LONG).show(); else Toast.makeText(this, "Update failed.", Toast.LENGTH_LONG).show(); db.close(); */ /* //---delete a Record--- db.open(); if (db.deleteRecord(1)) Toast.makeText(this, "Delete successful.", Toast.LENGTH_LONG).show(); else Toast.makeText(this, "Delete failed.", Toast.LENGTH_LONG).show(); db.close(); */ } private class DBAdapter extends BaseAdapter { private LayoutInflater mInflater; //private ArrayList<> @Override public int getCount() { return 0; } @Override public Object getItem(int arg0) { return null; } @Override public long getItemId(int arg0) { return 0; } @Override public View getView(int arg0, View arg1, ViewGroup arg2) { return null; } } public void CopyDB(InputStream inputStream, OutputStream outputStream) throws IOException { //---copy 1K bytes at a time--- byte[] buffer = new byte[1024]; int length; while ((length = inputStream.read(buffer)) > 0) { outputStream.write(buffer, 0, length); } inputStream.close(); outputStream.close(); } public void DisplayRecord(Cursor c) { Toast.makeText(this, "id: " + c.getString(0) + "\n" + "Title: " + c.getString(1) + "\n" + "Due Date: " + c.getString(2), Toast.LENGTH_SHORT).show(); } public void addAssignment(View view) { Intent i = new Intent("com.pinchtapzoom.addassignment"); startActivity(i); Log.d("TAG", "Clicked"); } } DBAdapter code: package com.example.studentdatabase; public class DBAdapter { public static final String KEY_ROWID = "id"; public static final String KEY_TITLE = "title"; public static final String KEY_DUEDATE = "duedate"; public static final String KEY_COURSE = "course"; public static final String KEY_NOTES = "notes"; private static final String TAG = "DBAdapter"; private static final String DATABASE_NAME = "AssignmentsDB"; private static final String DATABASE_TABLE = "assignments"; private static final int DATABASE_VERSION = 2; private static final String DATABASE_CREATE = "create table if not exists assignments (id integer primary key autoincrement, " + "title VARCHAR not null, duedate date, course VARCHAR, notes VARCHAR );"; 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) { try { db.execSQL(DATABASE_CREATE); } catch (SQLException e) { e.printStackTrace(); } } @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 contacts"); 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 record into the database--- public long insertRecord(String title, String duedate, String course, String notes) { ContentValues initialValues = new ContentValues(); initialValues.put(KEY_TITLE, title); initialValues.put(KEY_DUEDATE, duedate); initialValues.put(KEY_COURSE, course); initialValues.put(KEY_NOTES, notes); return db.insert(DATABASE_TABLE, null, initialValues); } //---deletes a particular record--- public boolean deleteContact(long rowId) { return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0; } //---retrieves all the records--- public Cursor getAllRecords() { return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TITLE, KEY_DUEDATE, KEY_COURSE, KEY_NOTES}, null, null, null, null, null); } //---retrieves a particular record--- public Cursor getRecord(long rowId) throws SQLException { Cursor mCursor = db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TITLE, KEY_DUEDATE, KEY_COURSE, KEY_NOTES}, KEY_ROWID + "=" + rowId, null, null, null, null, null); if (mCursor != null) { mCursor.moveToFirst(); } return mCursor; } //---updates a record--- public boolean updateRecord(long rowId, String title, String duedate, String course, String notes) { ContentValues args = new ContentValues(); args.put(KEY_TITLE, title); args.put(KEY_DUEDATE, duedate); args.put(KEY_COURSE, course); args.put(KEY_NOTES, notes); return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0; } } addassignment code: package com.example.studentdatabase; public class addassignment extends Activity { DBAdapter db = new DBAdapter(this); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.add); } public void addAssignment(View v) { Log.d("test", "adding"); //get data from form EditText nameTxt = (EditText)findViewById(R.id.editTitle); EditText dateTxt = (EditText)findViewById(R.id.editDuedate); EditText courseTxt = (EditText)findViewById(R.id.editCourse); EditText notesTxt = (EditText)findViewById(R.id.editNotes); db.open(); long id = db.insertRecord(nameTxt.getText().toString(), dateTxt.getText().toString(), courseTxt.getText().toString(), notesTxt.getText().toString()); db.close(); nameTxt.setText(""); dateTxt.setText(""); courseTxt.setText(""); notesTxt.setText(""); Toast.makeText(addassignment.this,"Assignment Added", Toast.LENGTH_LONG).show(); } public void viewAssignments(View v) { Intent i = new Intent(this, MainActivity.class); startActivity(i); } } What is wrong here? Thanks in advance.

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Building a “real” extension for Expression Blend

- by Timmy Kokke

.Last time I showed you how to get started building extensions for Expression Blend. Lets build a useful extension this time and go a bit deeper into Blend. Source of project => here Compiled dll => here (extract into /extensions folder of Expression Blend) The Extension When working on large Xaml files in Blend it’s often hard to find a specific control in the "Objects and Timeline Pane”. An extension that searches the active document and presents all elements that satisfy the query would be helpful. When the user starts typing a search query a search will be performed and the results are shown in the list. After the user selects an item in the results list, the control in the "Objects and Timeline Pane” will be selected. Below is a sketch of what it is going to look like. The Solution Create a new WPF User Control project as shown in the earlier tutorial in the Configuring the extension project section, but name it AdvancedSearch this time. Delete the default UserControl1.Xaml to clear the solution (a new user control will be added later thought, but adding a user control is easier then renaming one). Create the main entry point of the addin by adding a new class to the solution and naming this AdvancedSearchPackage. Add a reference to Microsoft.Expression.Extensibility and to System.ComponentModel.Composition . Implement the IPackage interface and add the Export attribute from the MEF to the definition. While you’re at it. Add references to Microsoft.Expression.DesignSurface, Microsoft.Expression.FrameWork and Microsoft.Expression.Markup. These will be used later. The Load method from the IPackage interface is going to create a ViewModel to bind to from the UI. Add another class to the solution and name this AdvancedSearchViewModel. This class needs to implement the INotifyPropertyChanged interface to enable notifications to the view. Add a constructor to the class that takes an IServices interface as a parameter. Create a new instance of the AdvancedSearchViewModel in the load method in the AdvanceSearchPackage class. The AdvancedSearchPackage class should looks like this now: using System.ComponentModel.Composition; using Microsoft.Expression.Extensibility; namespace AdvancedSearch { [Export(typeof(IPackage))] public class AdvancedSearchPackage:IPackage { public void Load(IServices services) { new AdvancedSearchViewModel(services); } public void Unload() { } } } Add a new UserControl to the project and name this AdvancedSearchView. The View will be created by the ViewModel, which will pass itself to the constructor of the view. Change the constructor of the View to take a AdvancedSearchViewModel object as a parameter. Add a private field to store the ViewModel and set this field in the constructor. Point the DataContext of the view to the ViewModel. The View will look something like this now: namespace AdvancedSearch { public partial class AdvancedSearchView:UserControl { private readonly AdvancedSearchViewModel _advancedSearchViewModel; public AdvancedSearchView(AdvancedSearchViewModel advancedSearchViewModel) { _advancedSearchViewModel = advancedSearchViewModel; InitializeComponent(); this.DataContext = _advancedSearchViewModel; } } } The View is going to be created in the constructor of the ViewModel and stored in a read only property. public FrameworkElement View { get; private set; } public AdvancedSearchViewModel(IServices services) { _services = services; View = new AdvancedSearchView(this); } The last thing the solution needs before we’ll wire things up is a new class, PossibleNode. This class will be used later to store the search results. The solution should look like this now: Adding UI to the UI The extension should build and run now, although nothing is showing up in Blend yet. To enable the user to perform a search query add a TextBox and a ListBox to the AdvancedSearchView.xaml file. I’ve set the rows of the grid too to make them look a little better. Add the TextChanged event to the TextBox and the SelectionChanged event to the ListBox, we’ll need those later on. <Grid> <Grid.RowDefinitions> <RowDefinition Height="32" /> <RowDefinition Height="*" /> </Grid.RowDefinitions> <TextBox TextChanged="SearchQueryTextChanged" HorizontalAlignment="Stretch" Margin="4" Name="SearchQuery" VerticalAlignment="Stretch" /> <ListBox SelectionChanged="SearchResultSelectionChanged" HorizontalAlignment="Stretch" Margin="4" Name="SearchResult" VerticalAlignment="Stretch" Grid.Row="1" /> </Grid> This will create a user interface like: To make the View show up in Blend it has to be registered with the WindowService. The GetService<T> method is used to get services from Blend, which are your entry points into Blend.When writing extensions you will encounter this method very often. In this case we’re asking for an IWindowService interface. The IWindowService interface serves events for changing windows and themes, is used for adding or removing resources and is used for registering and unregistering Palettes. All panes in Blend are palettes and are registered thru the RegisterPalette method. The first parameter passed to this method is a string containing a unique ID for the palette. This ID can be used to get access to the palette later. The second parameter is the View. The third parameter is a title for the pane. This title is shown when the pane is visible. It is also shown in the window menu of Blend. The last parameter is a KeyBinding. I have chosen Ctrl+Shift+F to call the Advanced Search pane. This value is also shown in the window menu of Blend. services.GetService<IWindowService>().RegisterPalette( "AdvancedSearch", viewModel.View, "Advanced Search", new KeyBinding { Key = Key.F, Modifiers = ModifierKeys.Control | ModifierKeys.Shift } ); You can compiler and run now. After Blend starts you can hit Ctrl+Shift+F or go the windows menu to call the advanced search extension. Searching for controls The search has to be cleared on every change of the active document. The DocumentServices fires an event every time a new document is opened, a document is closed or another document view is selected. Add the following line to the constructor of the ViewModel to handle the ActiveDocumentChanged event: _services.GetService<IDocumentService>().ActiveDocumentChanged += ActiveDocumentChanged; And implement the ActiveDocumentChanged method: private void ActiveDocumentChanged(object sender, DocumentChangedEventArgs e) { } To get to the contents of the document we first need to get access to the “Objects and Timeline” pane. This pane is registered in the PaletteRegistry in the same way as this extension has registered itself. The palettes are accessible thru an associative array. All you need to provide is the Identifier of the palette you want. The Id of the “Objects and Timeline” pane is “Designer_TimelinePane”. I’ve included a list of the other default panes at the bottom of this article. Each palette has a Content property which can be cast to the type of the pane. var timelinePane = (TimelinePane)_services.GetService<IWindowService>() .PaletteRegistry["Designer_TimelinePane"] .Content; Add a private field to the top of the AdvancedSearchViewModel class to store the active SceneViewModel. The SceneViewModel is needed to set the current selection and to get the little icons for the type of control. private SceneViewModel _activeSceneViewModel; When the active SceneViewModel changes, the ActiveSceneViewModel is stored in this field. The list of possible nodes is cleared and an PropertyChanged event is fired for this list to notify the UI to clear the list. This will make the eventhandler look like this: private void ActiveDocumentChanged(object sender, DocumentChangedEventArgs e) { var timelinePane = (TimelinePane)_services.GetService<IWindowService>() .PaletteRegistry["Designer_TimelinePane"].Content; _activeSceneViewModel = timelinePane.ActiveSceneViewModel; PossibleNodes = new List<PossibleNode>(); InvokePropertyChanged("PossibleNodes"); } The PossibleNode class used to store information about the controls found by the search. It’s a dumb data class with only 3 properties, the name of the control, the SceneNode and a brush used for the little icon. The SceneNode is the base class for every possible object you can create in Blend, like Brushes, Controls, Annotations, ResourceDictionaries and VisualStates. The entire PossibleNode class looks like this: using System.Windows.Media; using Microsoft.Expression.DesignSurface.ViewModel; namespace AdvancedSearch { public class PossibleNode { public string Name { get; set; } public SceneNode SceneNode { get; set; } public DrawingBrush IconBrush { get; set; } } } Add these two methods to the AdvancedSearchViewModel class: public void Search(string searchText) { } public void SelectElement(PossibleNode node){ } Both these methods are going to be called from the view. The Search method performs the search and updates the PossibleNodes list. The controls in the active document can be accessed thru TimeLineItemsManager class. This class contains a read only collection of TimeLineItems. By using a Linq query the possible nodes are selected and placed in the PossibleNodes list. var timelineItemManager = new TimelineItemManager(_activeSceneViewModel); PossibleNodes = new List<PossibleNode>( (from d in timelineItemManager.ItemList where d.DisplayName.ToLowerInvariant().StartsWith( searchText.ToLowerInvariant()) select new PossibleNode() { IconBrush = d.IconBrush, SceneNode = d.SceneNode, Name = d.DisplayName }).ToList() ); InvokePropertyChanged(InternalConst.PossibleNodes); The Select method is pretty straight forward. It contains two lines.The first to clear the selection. Otherwise the selected element would be added to the current selection. The second line selects the nodes. It is given a new array with the node to be selected. _activeSceneViewModel.ClearSelections(); _activeSceneViewModel.SelectNodes(new[] { node.SceneNode }); The last thing that needs to be done is to wire the whole thing to the View. The two event handlers just call the Search and SelectElement methods on the ViewModel. private void SearchQueryTextChanged(object sender, TextChangedEventArgs e) { _advancedSearchViewModel.Search(SearchQuery.Text); } private void SearchResultSelectionChanged(object sender, SelectionChangedEventArgs e) { if(e.AddedItems.Count>0) { _advancedSearchViewModel.SelectElement(e.AddedItems[0] as PossibleNode); } } The Listbox has to be bound to the PossibleNodes list and a simple DataTemplate is added to show the selection. The IconWithOverlay control can be found in the Microsoft.Expression.DesignSurface.UserInterface.Timeline.UI namespace in the Microsoft.Expression.DesignSurface assembly. The ListBox should look something like: <ListBox SelectionChanged="SearchResultSelectionChanged" HorizontalAlignment="Stretch" Margin="4" Name="SearchResult" VerticalAlignment="Stretch" Grid.Row="1" ItemsSource="{Binding PossibleNodes}"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <tlui:IconWithOverlay Margin="2,0,10,0" Width="12" Height="12" SourceBrush="{Binding Path=IconBrush, Mode=OneWay}" /> <TextBlock Text="{Binding Name}"/> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> Compile and run. Inside Blend the extension could look something like below. What’s Next When you’ve got the extension running. Try placing breakpoints in the code and see what else is in there. There’s a lot to explore and build extension on. I personally would love an extension to search for resources. Last but not least, you can download the source of project here. If you have any questions let me know. If you just want to use this extension, you can download the compiled dll here. Just extract the . zip into the /extensions folder of Expression Blend. Notes Target framework I ran into some issues when using the .NET Framework 4 Client Profile as a target framework. I got some strange error saying certain obvious namespaces could not be found, Microsoft.Expression in my case. If you run into something like this, try setting the target framework to .NET Framework 4 instead of the client version. Identifiers of default panes Identifier Type Title Designer_TimelinePane TimelinePane Objects and Timeline Designer_ToolPane ToolPane Tools Designer_ProjectPane ProjectPane Projects Designer_DataPane DataPane Data Designer_ResourcePane ResourcePane Resources Designer_PropertyInspector PropertyInspector Properties Designer_TriggersPane TriggersPane Triggers Interaction_Skin SkinView States Designer_AssetPane AssetPane Assets Interaction_Parts PartsPane Parts Designer_ResultsPane ResultsPane Results

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Bulk inserting best way to about it? + Helping me understand fully what I found so far

- by chobo2

Hi So I saw this post here and read it and it seems like bulk copy might be the way to go. http://stackoverflow.com/questions/682015/whats-the-best-way-to-bulk-database-inserts-from-c I still have some questions and want to know how things actually work. So I found 2 tutorials. http://www.codeproject.com/KB/cs/MultipleInsertsIn1dbTrip.aspx#_Toc196622241 http://www.codeproject.com/KB/linq/BulkOperations_LinqToSQL.aspx First way uses 2 ado.net 2.0 features. BulkInsert and BulkCopy. the second one uses linq to sql and OpenXML. This sort of appeals to me as I am using linq to sql already and prefer it over ado.net. However as one person pointed out in the posts what he just going around the issue at the cost of performance( nothing wrong with that in my opinion) First I will talk about the 2 ways in the first tutorial I am using VS2010 Express, .net 4.0, MVC 2.0, SQl Server 2005 Is ado.net 2.0 the most current version? Based on the technology I am using, is there some updates to what I am going to show that would improve it somehow? Is there any thing that these tutorial left out that I should know about? BulkInsert I am using this table for all the examples. CREATE TABLE [dbo].[TBL_TEST_TEST] ( ID INT IDENTITY(1,1) PRIMARY KEY, [NAME] [varchar](50) ) SP Code USE [Test] GO /****** Object: StoredProcedure [dbo].[sp_BatchInsert] Script Date: 05/19/2010 15:12:47 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER PROCEDURE [dbo].[sp_BatchInsert] (@Name VARCHAR(50) ) AS BEGIN INSERT INTO TBL_TEST_TEST VALUES (@Name); END C# Code /// <summary> /// Another ado.net 2.0 way that uses a stored procedure to do a bulk insert. /// Seems slower then "BatchBulkCopy" way and it crashes when you try to insert 500,000 records in one go. /// http://www.codeproject.com/KB/cs/MultipleInsertsIn1dbTrip.aspx#_Toc196622241 /// </summary> private static void BatchInsert() { // Get the DataTable with Rows State as RowState.Added DataTable dtInsertRows = GetDataTable(); SqlConnection connection = new SqlConnection(connectionString); SqlCommand command = new SqlCommand("sp_BatchInsert", connection); command.CommandType = CommandType.StoredProcedure; command.UpdatedRowSource = UpdateRowSource.None; // Set the Parameter with appropriate Source Column Name command.Parameters.Add("@Name", SqlDbType.VarChar, 50, dtInsertRows.Columns[0].ColumnName); SqlDataAdapter adpt = new SqlDataAdapter(); adpt.InsertCommand = command; // Specify the number of records to be Inserted/Updated in one go. Default is 1. adpt.UpdateBatchSize = 1000; connection.Open(); int recordsInserted = adpt.Update(dtInsertRows); connection.Close(); } So first thing is the batch size. Why would you set a batch size to anything but the number of records you are sending? Like I am sending 500,000 records so I did a Batch size of 500,000. Next why does it crash when I do this? If I set it to 1000 for batch size it works just fine. System.Data.SqlClient.SqlException was unhandled Message="A transport-level error has occurred when sending the request to the server. (provider: Shared Memory Provider, error: 0 - No process is on the other end of the pipe.)" Source=".Net SqlClient Data Provider" ErrorCode=-2146232060 Class=20 LineNumber=0 Number=233 Server="" State=0 StackTrace: at System.Data.Common.DbDataAdapter.UpdatedRowStatusErrors(RowUpdatedEventArgs rowUpdatedEvent, BatchCommandInfo[] batchCommands, Int32 commandCount) at System.Data.Common.DbDataAdapter.UpdatedRowStatus(RowUpdatedEventArgs rowUpdatedEvent, BatchCommandInfo[] batchCommands, Int32 commandCount) at System.Data.Common.DbDataAdapter.Update(DataRow[] dataRows, DataTableMapping tableMapping) at System.Data.Common.DbDataAdapter.UpdateFromDataTable(DataTable dataTable, DataTableMapping tableMapping) at System.Data.Common.DbDataAdapter.Update(DataTable dataTable) at TestIQueryable.Program.BatchInsert() in C:\Users\a\Downloads\TestIQueryable\TestIQueryable\TestIQueryable\Program.cs:line 124 at TestIQueryable.Program.Main(String[] args) in C:\Users\a\Downloads\TestIQueryable\TestIQueryable\TestIQueryable\Program.cs:line 16 InnerException: Time it took to insert 500,000 records with insert batch size of 1000 took "2 mins and 54 seconds" Of course this is no official time I sat there with a stop watch( I am sure there are better ways but was too lazy to look what they where) So I find that kinda slow compared to all my other ones(expect the linq to sql insert one) and I am not really sure why. Next I looked at bulkcopy /// <summary> /// An ado.net 2.0 way to mass insert records. This seems to be the fastest. /// http://www.codeproject.com/KB/cs/MultipleInsertsIn1dbTrip.aspx#_Toc196622241 /// </summary> private static void BatchBulkCopy() { // Get the DataTable DataTable dtInsertRows = GetDataTable(); using (SqlBulkCopy sbc = new SqlBulkCopy(connectionString, SqlBulkCopyOptions.KeepIdentity)) { sbc.DestinationTableName = "TBL_TEST_TEST"; // Number of records to be processed in one go sbc.BatchSize = 500000; // Map the Source Column from DataTabel to the Destination Columns in SQL Server 2005 Person Table // sbc.ColumnMappings.Add("ID", "ID"); sbc.ColumnMappings.Add("NAME", "NAME"); // Number of records after which client has to be notified about its status sbc.NotifyAfter = dtInsertRows.Rows.Count; // Event that gets fired when NotifyAfter number of records are processed. sbc.SqlRowsCopied += new SqlRowsCopiedEventHandler(sbc_SqlRowsCopied); // Finally write to server sbc.WriteToServer(dtInsertRows); sbc.Close(); } } This one seemed to go really fast and did not even need a SP( can you use SP with bulk copy? If you can would it be better?) BatchCopy had no problem with a 500,000 batch size.So again why make it smaller then the number of records you want to send? I found that with BatchCopy and 500,000 batch size it took only 5 seconds to complete. I then tried with a batch size of 1,000 and it only took 8 seconds. So much faster then the bulkinsert one above. Now I tried the other tutorial. USE [Test] GO /****** Object: StoredProcedure [dbo].[spTEST_InsertXMLTEST_TEST] Script Date: 05/19/2010 15:39:03 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER PROCEDURE [dbo].[spTEST_InsertXMLTEST_TEST](@UpdatedProdData nText) AS DECLARE @hDoc int exec sp_xml_preparedocument @hDoc OUTPUT,@UpdatedProdData INSERT INTO TBL_TEST_TEST(NAME) SELECT XMLProdTable.NAME FROM OPENXML(@hDoc, 'ArrayOfTBL_TEST_TEST/TBL_TEST_TEST', 2) WITH ( ID Int, NAME varchar(100) ) XMLProdTable EXEC sp_xml_removedocument @hDoc C# code. /// <summary> /// This is using linq to sql to make the table objects. /// It is then serailzed to to an xml document and sent to a stored proedure /// that then does a bulk insert(I think with OpenXML) /// http://www.codeproject.com/KB/linq/BulkOperations_LinqToSQL.aspx /// </summary> private static void LinqInsertXMLBatch() { using (TestDataContext db = new TestDataContext()) { TBL_TEST_TEST[] testRecords = new TBL_TEST_TEST[500000]; for (int count = 0; count < 500000; count++) { TBL_TEST_TEST testRecord = new TBL_TEST_TEST(); testRecord.NAME = "Name : " + count; testRecords[count] = testRecord; } StringBuilder sBuilder = new StringBuilder(); System.IO.StringWriter sWriter = new System.IO.StringWriter(sBuilder); XmlSerializer serializer = new XmlSerializer(typeof(TBL_TEST_TEST[])); serializer.Serialize(sWriter, testRecords); db.insertTestData(sBuilder.ToString()); } } So I like this because I get to use objects even though it is kinda redundant. I don't get how the SP works. Like I don't get the whole thing. I don't know if OPENXML has some batch insert under the hood but I do not even know how to take this example SP and change it to fit my tables since like I said I don't know what is going on. I also don't know what would happen if the object you have more tables in it. Like say I have a ProductName table what has a relationship to a Product table or something like that. In linq to sql you could get the product name object and make changes to the Product table in that same object. So I am not sure how to take that into account. I am not sure if I would have to do separate inserts or what. The time was pretty good for 500,000 records it took 52 seconds The last way of course was just using linq to do it all and it was pretty bad. /// <summary> /// This is using linq to sql to to insert lots of records. /// This way is slow as it uses no mass insert. /// Only tried to insert 50,000 records as I did not want to sit around till it did 500,000 records. /// http://www.codeproject.com/KB/linq/BulkOperations_LinqToSQL.aspx /// </summary> private static void LinqInsertAll() { using (TestDataContext db = new TestDataContext()) { db.CommandTimeout = 600; for (int count = 0; count < 50000; count++) { TBL_TEST_TEST testRecord = new TBL_TEST_TEST(); testRecord.NAME = "Name : " + count; db.TBL_TEST_TESTs.InsertOnSubmit(testRecord); } db.SubmitChanges(); } } I did only 50,000 records and that took over a minute to do. So I really narrowed it done to the linq to sql bulk insert way or bulk copy. I am just not sure how to do it when you have relationship for either way. I am not sure how they both stand up when doing updates instead of inserts as I have not gotten around to try it yet. I don't think I will ever need to insert/update more than 50,000 records at one type but at the same time I know I will have to do validation on records before inserting so that will slow it down and that sort of makes linq to sql nicer as your got objects especially if your first parsing data from a xml file before you insert into the database. Full C# code using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Xml.Serialization; using System.Data; using System.Data.SqlClient; namespace TestIQueryable { class Program { private static string connectionString = ""; static void Main(string[] args) { BatchInsert(); Console.WriteLine("done"); } /// <summary> /// This is using linq to sql to to insert lots of records. /// This way is slow as it uses no mass insert. /// Only tried to insert 50,000 records as I did not want to sit around till it did 500,000 records. /// http://www.codeproject.com/KB/linq/BulkOperations_LinqToSQL.aspx /// </summary> private static void LinqInsertAll() { using (TestDataContext db = new TestDataContext()) { db.CommandTimeout = 600; for (int count = 0; count < 50000; count++) { TBL_TEST_TEST testRecord = new TBL_TEST_TEST(); testRecord.NAME = "Name : " + count; db.TBL_TEST_TESTs.InsertOnSubmit(testRecord); } db.SubmitChanges(); } } /// <summary> /// This is using linq to sql to make the table objects. /// It is then serailzed to to an xml document and sent to a stored proedure /// that then does a bulk insert(I think with OpenXML) /// http://www.codeproject.com/KB/linq/BulkOperations_LinqToSQL.aspx /// </summary> private static void LinqInsertXMLBatch() { using (TestDataContext db = new TestDataContext()) { TBL_TEST_TEST[] testRecords = new TBL_TEST_TEST[500000]; for (int count = 0; count < 500000; count++) { TBL_TEST_TEST testRecord = new TBL_TEST_TEST(); testRecord.NAME = "Name : " + count; testRecords[count] = testRecord; } StringBuilder sBuilder = new StringBuilder(); System.IO.StringWriter sWriter = new System.IO.StringWriter(sBuilder); XmlSerializer serializer = new XmlSerializer(typeof(TBL_TEST_TEST[])); serializer.Serialize(sWriter, testRecords); db.insertTestData(sBuilder.ToString()); } } /// <summary> /// An ado.net 2.0 way to mass insert records. This seems to be the fastest. /// http://www.codeproject.com/KB/cs/MultipleInsertsIn1dbTrip.aspx#_Toc196622241 /// </summary> private static void BatchBulkCopy() { // Get the DataTable DataTable dtInsertRows = GetDataTable(); using (SqlBulkCopy sbc = new SqlBulkCopy(connectionString, SqlBulkCopyOptions.KeepIdentity)) { sbc.DestinationTableName = "TBL_TEST_TEST"; // Number of records to be processed in one go sbc.BatchSize = 500000; // Map the Source Column from DataTabel to the Destination Columns in SQL Server 2005 Person Table // sbc.ColumnMappings.Add("ID", "ID"); sbc.ColumnMappings.Add("NAME", "NAME"); // Number of records after which client has to be notified about its status sbc.NotifyAfter = dtInsertRows.Rows.Count; // Event that gets fired when NotifyAfter number of records are processed. sbc.SqlRowsCopied += new SqlRowsCopiedEventHandler(sbc_SqlRowsCopied); // Finally write to server sbc.WriteToServer(dtInsertRows); sbc.Close(); } } /// <summary> /// Another ado.net 2.0 way that uses a stored procedure to do a bulk insert. /// Seems slower then "BatchBulkCopy" way and it crashes when you try to insert 500,000 records in one go. /// http://www.codeproject.com/KB/cs/MultipleInsertsIn1dbTrip.aspx#_Toc196622241 /// </summary> private static void BatchInsert() { // Get the DataTable with Rows State as RowState.Added DataTable dtInsertRows = GetDataTable(); SqlConnection connection = new SqlConnection(connectionString); SqlCommand command = new SqlCommand("sp_BatchInsert", connection); command.CommandType = CommandType.StoredProcedure; command.UpdatedRowSource = UpdateRowSource.None; // Set the Parameter with appropriate Source Column Name command.Parameters.Add("@Name", SqlDbType.VarChar, 50, dtInsertRows.Columns[0].ColumnName); SqlDataAdapter adpt = new SqlDataAdapter(); adpt.InsertCommand = command; // Specify the number of records to be Inserted/Updated in one go. Default is 1. adpt.UpdateBatchSize = 500000; connection.Open(); int recordsInserted = adpt.Update(dtInsertRows); connection.Close(); } private static DataTable GetDataTable() { // You First need a DataTable and have all the insert values in it DataTable dtInsertRows = new DataTable(); dtInsertRows.Columns.Add("NAME"); for (int i = 0; i < 500000; i++) { DataRow drInsertRow = dtInsertRows.NewRow(); string name = "Name : " + i; drInsertRow["NAME"] = name; dtInsertRows.Rows.Add(drInsertRow); } return dtInsertRows; } static void sbc_SqlRowsCopied(object sender, SqlRowsCopiedEventArgs e) { Console.WriteLine("Number of records affected : " + e.RowsCopied.ToString()); } } }

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data is not inserting in my db table [closed]

- by Sarojit Chakraborty

Please see my below(SubjectDetailsDao.java) code of addZoneToDb method. My debugger is nicely running upto ** session.getTransaction().commit();** code. but after that debugger stops,I do not know why it stops after that line? .And because of this i am unable to insert my data into my database table. I don't know what to do.Why it is not inserting my data into my database table? Plz help me for this. H Now i am getting this Error: Struts Problem Report Struts has detected an unhandled exception: Messages: org.hibernate.event.PreInsertEvent.getSource()Lorg/hibernate/event/EventSource; File: org/hibernate/validator/event/ValidateEventListener.java Line number: 172 Stacktraces java.lang.reflect.InvocationTargetException sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) java.lang.reflect.Method.invoke(Method.java:601) com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441) com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243) com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252) org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:130) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:165) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:179) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52) org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488) org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77) org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91) org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240) org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164) org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498) org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100) org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562) org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394) org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243) org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188) org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) java.lang.Thread.run(Thread.java:722) java.lang.NoSuchMethodError: org.hibernate.event.PreInsertEvent.getSource()Lorg/hibernate/event/EventSource; org.hibernate.validator.event.ValidateEventListener.onPreInsert(ValidateEventListener.java:172) org.hibernate.action.EntityInsertAction.preInsert(EntityInsertAction.java:156) org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:49) org.hibernate.engine.ActionQueue.execute(ActionQueue.java:250) org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:234) org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:141) org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298) org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27) org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000) org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338) org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106) v.esoft.dao.SubjectdetailsDAO.SubjectdetailsDAO.addZoneToDb(SubjectdetailsDAO.java:185) v.esoft.actions.LoginAction.datatobeinsert(LoginAction.java:53) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) java.lang.reflect.Method.invoke(Method.java:601) com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441) com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243) com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252) org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68) ............................... ............................... SubjectDetailsDao.java(I have problem in addZoneToDb) package v.esoft.dao.SubjectdetailsDAO; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import org.hibernate.HibernateException; import org.hibernate.Query; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.hibernate.criterion.Order; import com.opensymphony.xwork2.ActionSupport; import v.esoft.connection.HibernateUtil; import v.esoft.pojos.Subjectdetails; public class SubjectdetailsDAO extends ActionSupport { private static Session session = null; private static SessionFactory sessionFactory = null; static Transaction transaction = null; private String currentDate; SimpleDateFormat formatter1 = new SimpleDateFormat("yyyy-MM-dd"); private java.util.Date currentdate; public SubjectdetailsDAO() { sessionFactory = HibernateUtil.getSessionFactory(); SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd"); currentdate = new java.util.Date(); currentDate = formatter.format(currentdate); } public List getAllCustomTempleteRoutinesForGrid() { List list = new ArrayList(); try { session = sessionFactory.openSession(); list = session.createCriteria(Subjectdetails.class).addOrder(Order.desc("subjectId")).list(); } catch (Exception e) { System.out.println("Exepetion in getAllCustomTempleteRoutines" + e); } finally { try { // HibernateUtil.shutdown(); } catch (Exception e) { System.out.println("Exception In getExerciseListByLoginId Resource closing :" + e); } } return list; } //**showing list on grid private static List<Subjectdetails> custLst=new ArrayList<Subjectdetails>(); static int total=50; static { SubjectdetailsDAO cts = new SubjectdetailsDAO(); Iterator iterator1 = cts.getAllCustomTempleteRoutinesForGrid().iterator(); while (iterator1.hasNext()) { Subjectdetails get = (Subjectdetails) iterator1.next(); custLst.add(get); } } /****************************************update Routines List by WorkId************************************/ public int updatesub(Subjectdetails s) { int updated = 0; try { session = sessionFactory.openSession(); transaction = session.beginTransaction(); Query query = session.createQuery("UPDATE Subjectdetails set subjectName = :routineName1 WHERE subjectId=:workoutId1"); query.setString("routineName1", s.getSubjectName()); query.setInteger("workoutId1", s.getSubjectId()); updated = query.executeUpdate(); if (updated != 0) { } transaction.commit(); } catch (Exception e) { if (transaction != null && transaction.isActive()) { try { transaction.rollback(); } catch (Exception e1) { System.out.println("Exception in addUser() Rollback :" + e1); } } } finally { try { session.flush(); session.close(); } catch (Exception e) { System.out.println("Exception In addUser Resource closing :" + e); } } return updated; } /****************************************update Routines List by WorkId************************************/ public int addSubjectt(Subjectdetails s) { int inserted = 0; Subjectdetails ss=new Subjectdetails(); try { session = sessionFactory.openSession(); transaction = session.beginTransaction(); ss. setSubjectName(s.getSubjectName()); session.save(ss); System.out.println("Successfully data insert in database"); inserted++; if (inserted != 0) { } transaction.commit(); } catch (Exception e) { if (transaction != null && transaction.isActive()) { try { transaction.rollback(); } catch (Exception e1) { System.out.println("Exception in addUser() Rollback :" + e1); } } } finally { try { session.flush(); session.close(); } catch (Exception e) { System.out.println("Exception In addUser Resource closing :" + e); } } return inserted; } /******************************************Get all Routines List by LoginID************************************/ public List getSubjects() { List list = null; try { session = sessionFactory.openSession(); list = session.createCriteria(Subjectdetails.class).list(); } catch (Exception e) { System.out.println("Exception in getRoutineList() :" + e); } finally { try { session.flush(); session.close(); } catch (Exception e) { System.out.println("Exception In getUserList Resource closing :" + e); } } return list; } //---\ public int addZoneToDb(String countryName, Integer loginId) { int inserted = 0; try { System.out.println("---------1--------"); Session session = HibernateUtil.getSessionFactory().openSession(); System.out.println("---------2------session--"+session); session.beginTransaction(); Subjectdetails country = new Subjectdetails(countryName, loginId, currentdate, loginId, currentdate); System.out.println("---------2------country--"+country); session.save(country); System.out.println("-------after save--"); inserted++; session.getTransaction().commit(); System.out.println("-------after commits--"); } catch (Exception e) { if (transaction != null && transaction.isActive()) { try { transaction.rollback(); } catch (Exception e1) { } } } finally { try { } catch (Exception e) { } } return inserted; } //-- public int nextId() { return total++; } public List<Subjectdetails> buildList() { return custLst; } public static int count() { return custLst.size(); } public static List<Subjectdetails> find(int o,int q) { return custLst.subList(o, q); } public void save(Subjectdetails c) { custLst.add(c); } public static Subjectdetails findById(Integer id) { try { for(Subjectdetails c:custLst) { if(c.getSubjectId()==id) { return c; } } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return null; } public void update(Subjectdetails c) { for(Subjectdetails x:custLst) { if(x.getSubjectId()==c.getSubjectId()) { x.setSubjectName(c.getSubjectName()); } } } public void delete(Subjectdetails c) { custLst.remove(c); } public static List<Subjectdetails> findNotById(int id, int from,int to) { List<Subjectdetails> subLst=custLst.subList(from, to); List<Subjectdetails> temp=new ArrayList<Subjectdetails>(); for(Subjectdetails c:subLst) { if(c.getSubjectId()!=id) { temp.add(c); } } return temp; } public static List<Subjectdetails> findLesserAsId(int id, int from,int to) { List<Subjectdetails> subLst=custLst.subList(from, to); List<Subjectdetails> temp=new ArrayList<Subjectdetails>(); for(Subjectdetails c:subLst) { if(c.getSubjectId()<=id) { temp.add(c); } } return temp; } public static List<Subjectdetails> findGreaterAsId(int id, int from,int to) { List<Subjectdetails> subLst=custLst.subList(from, to); List<Subjectdetails> temp=new ArrayList<Subjectdetails>(); for(Subjectdetails c:subLst) { if(c.getSubjectId()>=id) { temp.add(c); } } return temp; } } Subjectdetails.hbm.xml <hibernate-mapping> <class name="vb.sofware.pojos.Subjectdetails" table="subjectdetails" catalog="vbsoftware"> <id name="subjectId" type="int"> <column name="subject_id" /> <generator class="increment"/> </id> <property name="subjectName" type="string"> <column name="subject_name" length="150" /> </property> <property name="createrId" type="java.lang.Integer"> <column name="creater_id" /> </property> <property name="createdDate" type="timestamp"> <column name="created_date" length="19" /> </property> <property name="updateId" type="java.lang.Integer"> <column name="update_id" /> </property> <property name="updatedDate" type="timestamp"> <column name="updated_date" length="19" /> </property> </class> </hibernate-mapping> My POJO - Subjectdetails.java package v.esoft.pojos; // Generated Oct 6, 2012 1:58:21 PM by Hibernate Tools 3.4.0.CR1 import java.util.Date; /** * Subjectdetails generated by hbm2java */ public class Subjectdetails implements java.io.Serializable { private int subjectId; private String subjectName; private Integer createrId; private Date createdDate; private Integer updateId; private Date updatedDate; public Subjectdetails( String subjectName) { //this.subjectId = subjectId; this.subjectName = subjectName; } public Subjectdetails() { } public Subjectdetails(int subjectId) { this.subjectId = subjectId; } public Subjectdetails(int subjectId, String subjectName, Integer createrId, Date createdDate, Integer updateId, Date updatedDate) { this.subjectId = subjectId; this.subjectName = subjectName; this.createrId = createrId; this.createdDate = createdDate; this.updateId = updateId; this.updatedDate = updatedDate; } public Subjectdetails( String subjectName, Integer createrId, Date createdDate, Integer updateId, Date updatedDate) { this.subjectName = subjectName; this.createrId = createrId; this.createdDate = createdDate; this.updateId = updateId; this.updatedDate = updatedDate; } public int getSubjectId() { return this.subjectId; } public void setSubjectId(int subjectId) { this.subjectId = subjectId; } public String getSubjectName() { return this.subjectName; } public void setSubjectName(String subjectName) { this.subjectName = subjectName; } public Integer getCreaterId() { return this.createrId; } public void setCreaterId(Integer createrId) { this.createrId = createrId; } public Date getCreatedDate() { return this.createdDate; } public void setCreatedDate(Date createdDate) { this.createdDate = createdDate; } public Integer getUpdateId() { return this.updateId; } public void setUpdateId(Integer updateId) { this.updateId = updateId; } public Date getUpdatedDate() { return this.updatedDate; } public void setUpdatedDate(Date updatedDate) { this.updatedDate = updatedDate; } } And my Sql query is CREATE TABLE IF NOT EXISTS `subjectdetails` ( `subject_id` int(3) NOT NULL, `subject_name` varchar(150) DEFAULT NULL, `creater_id` int(5) DEFAULT NULL, `created_date` datetime DEFAULT NULL, `update_id` int(5) DEFAULT NULL, `updated_date` datetime DEFAULT NULL, PRIMARY KEY (`subject_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1;

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MVC : Does Code to save data in cache or session belongs in controller?

- by newbie

I'm a bit confused if saving the information to session code below, belongs in the controller action as shown below or should it be part of my Model? I would add that I have other controller methods that will read this session value later. public ActionResult AddFriend(FriendsContext viewModel) { if (!ModelState.IsValid) { return View(viewModel); } // Start - Confused if the code block below belongs in Controller? Friend friend = new Friend(); friend.FirstName = viewModel.FirstName; friend.LastName = viewModel.LastName; friend.Email = viewModel.UserEmail; httpContext.Session["latest-friend"] = friend; // End Confusion return RedirectToAction("Home"); } I thought about adding a static utility class in my Model which does something like below, but it just seems stupid to add 2 lines of code in another file. public static void SaveLatestFriend(Friend friend, HttpContextBase httpContext) { httpContext.Session["latest-friend"] = friend; } public static Friend GetLatestFriend(HttpContextBase httpContext) { return httpContext.Session["latest-friend"] as Friend; }

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Convert Dynamic to Type and convert Type to Dynamic

- by Jon Canning

public static class DynamicExtensions { public static T FromDynamic<T>(this IDictionary<string, object> dictionary) { var bindings = new List<MemberBinding>(); foreach (var sourceProperty in typeof(T).GetProperties().Where(x => x.CanWrite)) { var key = dictionary.Keys.SingleOrDefault(x => x.Equals(sourceProperty.Name, StringComparison.OrdinalIgnoreCase)); if (string.IsNullOrEmpty(key)) continue; var propertyValue = dictionary[key]; bindings.Add(Expression.Bind(sourceProperty, Expression.Constant(propertyValue))); } Expression memberInit = Expression.MemberInit(Expression.New(typeof(T)), bindings); return Expression.Lambda<Func<T>>(memberInit).Compile().Invoke(); } public static dynamic ToDynamic<T>(this T obj) { IDictionary<string, object> expando = new ExpandoObject(); foreach (var propertyInfo in typeof(T).GetProperties()) { var propertyExpression = Expression.Property(Expression.Constant(obj), propertyInfo); var currentValue = Expression.Lambda<Func<string>>(propertyExpression).Compile().Invoke(); expando.Add(propertyInfo.Name.ToLower(), currentValue); } return expando as ExpandoObject; } }

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Code Trivia #6

- by João Angelo

It’s time for yet another code trivia and it’s business as usual. What will the following program output to the console? using System; using System.Drawing; using System.Threading; class Program { [ThreadStatic] static Point Mark = new Point(1, 1); static void Main() { Thread.CurrentThread.Name = "A"; MoveMarkUp(); var helperThread = new Thread(MoveMarkUp) { Name = "B" }; helperThread.Start(); helperThread.Join(); } static void MoveMarkUp() { Mark.Y++; Console.WriteLine("{0}:{1}", Thread.CurrentThread.Name, Mark); } }

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Dynamic Tab Implementation in ADF

- by Vijay Mohan

Well, this can be a common usecase across apps to open tabs dynamically at runtime based on the request.Well, in order to achieve this you can have a parent container, lets say a panelTab component.Inside panelTab , u can have a showDetailItem inside an af:foreach or an af:iterator binded to a bean static list which will have as many show detail items as you wish to be shown.something like this.private static List = { new showDetailItem("1"),new ShowDetailItem("2") ...};now in the backing bean you can have a method that takes care of rendering and disclosing an specific tab based on the index.public void openMyTab(){List<MyItems> list = refToParentContainer.getChildren();int indexOfTabToBeOpened = //Write a method that will compute the tab index of the next //tab.list.get(index).setRendered(true);list.get(index).setDisclosed(true);similarly you can set other properties too.}Else, instead of having af:foreach/iterator iterating through the SD items , you can go for static SDs in the page with render property set to false and then you can follow the same approach to render/disclose it at runtime.

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ResponseStatusLine protocol violation

- by Tom Hines

I parse/scrape a few web page every now and then and recently ran across an error that stated: "The server committed a protocol violation. Section=ResponseStatusLine". After a few web searches, I found a couple of suggestions – one of which said the problem could be fixed by changing the HttpWebRequest ProtocolVersion to 1.0 with the command: 1: HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(strURI); 2: req.ProtocolVersion = HttpVersion.Version10; …but that did not work in my particular case. What DID work was the next suggestion I found that suggested the use of the setting: “useUnsafeHeaderParsing” either in the app.config file or programmatically. If added to the app.config, it would be: 1:  2: <system.net> 3: <settings> 4: <httpWebRequest useUnsafeHeaderParsing ="true"/> 5: </settings> 6: </system.net> If done programmatically, it would look like this: C++: 1: // UUHP_CPP.h 2: #pragma once 3: using namespace System; 4: using namespace System::Reflection; 5: 6: namespace UUHP_CPP 7: { 8: public ref class CUUHP_CPP 9: { 10: public: 11: static bool UseUnsafeHeaderParsing(String^% strError) 12: { 13: Assembly^ assembly = Assembly::GetAssembly(System::Net::Configuration::SettingsSection::typeid); //__typeof 14: if (nullptr==assembly) 15: { 16: strError = "Could not access Assembly"; 17: return false; 18: } 19: 20: Type^ type = assembly->GetType("System.Net.Configuration.SettingsSectionInternal"); 21: if (nullptr==type) 22: { 23: strError = "Could not access internal settings"; 24: return false; 25: } 26: 27: Object^ obj = type->InvokeMember("Section", 28: BindingFlags::Static | BindingFlags::GetProperty | BindingFlags::NonPublic, 29: nullptr, nullptr, gcnew array<Object^,1>(0)); 30: 31: if(nullptr == obj) 32: { 33: strError = "Could not invoke Section member"; 34: return false; 35: } 36: 37: FieldInfo^ fi = type->GetField("useUnsafeHeaderParsing", BindingFlags::NonPublic | BindingFlags::Instance); 38: if(nullptr == fi) 39: { 40: strError = "Could not access useUnsafeHeaderParsing field"; 41: return false; 42: } 43: 44: if (!(bool)fi->GetValue(obj)) 45: { 46: fi->SetValue(obj, true); 47: } 48: 49: return true; 50: } 51: }; 52: } C# (CSharp): 1: using System; 2: using System.Reflection; 3: 4: namespace UUHP_CS 5: { 6: public class CUUHP_CS 7: { 8: public static bool UseUnsafeHeaderParsing(ref string strError) 9: { 10: Assembly assembly = Assembly.GetAssembly(typeof(System.Net.Configuration.SettingsSection)); 11: if (null == assembly) 12: { 13: strError = "Could not access Assembly"; 14: return false; 15: } 16: 17: Type type = assembly.GetType("System.Net.Configuration.SettingsSectionInternal"); 18: if (null == type) 19: { 20: strError = "Could not access internal settings"; 21: return false; 22: } 23: 24: object obj = type.InvokeMember("Section", 25: BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.NonPublic, 26: null, null, new object[] { }); 27: 28: if (null == obj) 29: { 30: strError = "Could not invoke Section member"; 31: return false; 32: } 33: 34: // If it's not already set, set it. 35: FieldInfo fi = type.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic | BindingFlags.Instance); 36: if (null == fi) 37: { 38: strError = "Could not access useUnsafeHeaderParsing field"; 39: return false; 40: } 41: 42: if (!Convert.ToBoolean(fi.GetValue(obj))) 43: { 44: fi.SetValue(obj, true); 45: } 46: 47: return true; 48: } 49: } 50: } F# (FSharp): 1: namespace UUHP_FS 2: open System 3: open System.Reflection 4: module CUUHP_FS = 5: let UseUnsafeHeaderParsing(strError : byref<string>) : bool = 6: // 7: let assembly : Assembly = Assembly.GetAssembly(typeof<System.Net.Configuration.SettingsSection>) 8: if (null = assembly) then 9: strError <- "Could not access Assembly" 10: false 11: else 12: 13: let myType : Type = assembly.GetType("System.Net.Configuration.SettingsSectionInternal") 14: if (null = myType) then 15: strError <- "Could not access internal settings" 16: false 17: else 18: 19: let obj : Object = myType.InvokeMember("Section", BindingFlags.Static ||| BindingFlags.GetProperty ||| BindingFlags.NonPublic, null, null, Array.zeroCreate 0) 20: if (null = obj) then 21: strError <- "Could not invoke Section member" 22: false 23: else 24: 25: // If it's not already set, set it. 26: let fi : FieldInfo = myType.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic ||| BindingFlags.Instance) 27: if(null = fi) then 28: strError <- "Could not access useUnsafeHeaderParsing field" 29: false 30: else 31: 32: if (not(Convert.ToBoolean(fi.GetValue(obj)))) then 33: fi.SetValue(obj, true) 34: 35: // Now return true 36: true VB (Visual Basic): 1: Option Explicit On 2: Option Strict On 3: Imports System 4: Imports System.Reflection 5: 6: Public Class CUUHP_VB 7: Public Shared Function UseUnsafeHeaderParsing(ByRef strError As String) As Boolean 8: 9: Dim assembly As [Assembly] 10: assembly = [assembly].GetAssembly(GetType(System.Net.Configuration.SettingsSection)) 11: 12: If (assembly Is Nothing) Then 13: strError = "Could not access Assembly" 14: Return False 15: End If 16: 17: Dim type As Type 18: type = [assembly].GetType("System.Net.Configuration.SettingsSectionInternal") 19: If (type Is Nothing) Then 20: strError = "Could not access internal settings" 21: Return False 22: End If 23: 24: Dim obj As Object 25: obj = [type].InvokeMember("Section", _ 26: BindingFlags.Static Or BindingFlags.GetProperty Or BindingFlags.NonPublic, _ 27: Nothing, Nothing, New [Object]() {}) 28: 29: If (obj Is Nothing) Then 30: strError = "Could not invoke Section member" 31: Return False 32: End If 33: 34: ' If it's not already set, set it. 35: Dim fi As FieldInfo 36: fi = [type].GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic Or BindingFlags.Instance) 37: If (fi Is Nothing) Then 38: strError = "Could not access useUnsafeHeaderParsing field" 39: Return False 40: End If 41: 42: If (Not Convert.ToBoolean(fi.GetValue(obj))) Then 43: fi.SetValue(obj, True) 44: End If 45: 46: Return True 47: End Function 48: End Class Technorati Tags: C++,CPP,VB,Visual Basic,F#,FSharp,C#,CSharp,ResponseStatusLine,protocol violation

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Why prefer a wildcard to a type discriminator in a Java API (Re: Effective Java)

- by Michael Campbell

In the generics section of Bloch's Effective Java (which handily is the "free" chapter available to all: http://java.sun.com/docs/books/effective/generics.pdf), he says: If a type parameter appears only once in a method declaration, replace it with a wildcard. (See page 31-33 of that pdf) The signature in question is: public static void swap(List<?> list, int i, int j) vs public static void swap(List<E> list, int i, int j) And then proceeds to use a static private "helper" function with an actual type parameter to perform the work. The helper function signature is EXACTLY that of the second option. Why is the wildcard preferable, since you need to NOT use a wildcard to get the work done anyway? I understand that in this case since he's modifying the List and you can't add to a collection with an unbounded wildcard, so why use it at all?

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How can I host a website on a dynamically-assigned IP address?

- by nick

I recently upgraded my internet to the point that it is much faster and more reliable than my current webhost. I would like to move my current domain to be hosted at home, but my IP address is dynamic. As far as I know, I only get a new IP when I restart my modem and or router (which is almost never) or when cable one (my ISP) pushes out a firmware update (rarely). There are a few ways I can see doing this: Convince my ISP to give me a static IP Assign my router my current IP to force a static IP (which might work?) Set my DNS record to my current IP address and update it on the rare occasions that it changes. Obviously I'm hoping that the first one works, but I don't want to pay a lot of extra money (if that's what it takes) to get a static IP address. Which of these options will work most reliably?

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SQL ADO.NET shortcut extensions (old school!)

- by Jeff

As much as I love me some ORM's (I've used LINQ to SQL quite a bit, and for the MSDN/TechNet Profile and Forums we're using NHibernate more and more), there are times when it's appropriate, and in some ways more simple, to just throw up so old school ADO.NET connections, commands, readers and such. It still feels like a pain though to new up all the stuff, make sure it's closed, blah blah blah. It's pretty much the least favorite task of writing data access code. To minimize the pain, I have a set of extension methods that I like to use that drastically reduce the code you have to write. Here they are... public static void Using(this SqlConnection connection, Action<SqlConnection> action) { connection.Open(); action(connection); connection.Close(); } public static SqlCommand Command(this SqlConnection connection, string sql){ var command = new SqlCommand(sql, connection); return command;}public static SqlCommand AddParameter(this SqlCommand command, string parameterName, object value){ command.Parameters.AddWithValue(parameterName, value); return command;}public static object ExecuteAndReturnIdentity(this SqlCommand command){ if (command.Connection == null) throw new Exception("SqlCommand has no connection."); command.ExecuteNonQuery(); command.Parameters.Clear(); command.CommandText = "SELECT @@IDENTITY"; var result = command.ExecuteScalar(); return result;}public static SqlDataReader ReadOne(this SqlDataReader reader, Action<SqlDataReader> action){ if (reader.Read()) action(reader); reader.Close(); return reader;}public static SqlDataReader ReadAll(this SqlDataReader reader, Action<SqlDataReader> action){ while (reader.Read()) action(reader); reader.Close(); return reader;} It has been awhile since I've really revisited these, so you will likely find opportunity for further optimization. The bottom line here is that you can chain together a bunch of these methods to make a much more concise database call, in terms of the code on your screen, anyway. Here are some examples: public Dictionary<string, string> Get(){ var dictionary = new Dictionary<string, string>(); _sqlHelper.GetConnection().Using(connection => connection.Command("SELECT Setting, [Value] FROM Settings") .ExecuteReader() .ReadAll(r => dictionary.Add(r.GetString(0), r.GetString(1)))); return dictionary;} or... public void ChangeName(User user, string newName){ _sqlHelper.GetConnection().Using(connection => connection.Command("UPDATE Users SET Name = @Name WHERE UserID = @UserID") .AddParameter("@Name", newName) .AddParameter("@UserID", user.UserID) .ExecuteNonQuery());} The _sqlHelper.GetConnection() is just some other code that gets a connection object for you. You might have an even cleaner way to take that step out entirely. This looks more fluent, and the real magic sauce for me is the reader bits where you can put any kind of arbitrary method in there to iterate over the results.

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creating a pre-menu level select screen

- by Ephiras

Hi I am working on creating a tower Defence java applet game and have come to a road block about implementing a title screen that i can select the level and difficulty of the rest of the game. my title screen class is called Menu. from this menu class i need to pass in many different variables into my Main class. i have used different classes before and know how to run them and such. but if both classes extend applet and each has its individual graphics method how can i run things from Main even though it was created in Menu. what i essentially want to do is run the Menu class withits action listeners and graphics until a Difficulty button has been selected, run the main class (which 100% works without having to have the Menu class) and pretty much terminate Menu so that i cannot go back to it, do not see its buttons or graphics menus. can i run one applet annd when i choose a button close that one and launch the other one? IF you would like to download the full project you can find it here, i had to comment out all the code that wasn't working my Menu class import java.awt.*; import java.awt.event.*; import java.applet.*; public class Menu extends Applet implements ActionListener{ Button bEasy,bMed,bHard; Main m; public void init(){ bEasy= new Button("Easy"); bEasy.setBounds(140,200,100,50); add(bEasy); bMed = new Button("Medium");bMed.setBounds(280,200,100,50); add(bMed); bHard= new Button("Hard");bHard.setBounds(420,200,100,50); add(bHard); setLayout(null); } public void actionPerformed(ActionEvent e){ Main m = new Main(20,10,3000,mapMed);//break; switch (e.getSource()){ case bEasy: Main m = new Main(6000,20,"levels/levelEasy.png");break;//enimies tower money world case bMed: Main m = new Main(4000,15,"levels/levelMed.png");break; case bHard: Main m = new Main(2000,10,"levels/levelEasy.png");break; default: break; } } public void paint(){ //m.draw(g) } } and here is my main class initialising code. import java.awt.*; import java.awt.event.*; import java.applet.*; import java.io.IOException; public class Main extends Applet implements Runnable, MouseListener, MouseMotionListener, ActionListener{ Button startButton, UpgRange, UpgDamage; //set up the buttons Color roadCol,startCol,finCol,selGrass,selRoad; //set up the colors Enemy e[][]; Tower t[]; Image towerpic,backpic,roadpic,levelPic; private Image i; private Graphics doubleG; //here is the world 0=grass 1=road 2=start 3=end int world[][],eStartX,eStartY; boolean drawMouse,gameEnd; static boolean start=false; static int gridLength=15; static int round=0; int Mx,My,timer=1500; static int sqrSize=31; int towers=0,towerSelected=-10; static int castleHealth=2000; String levelPath; //choose the level Easy Med or Hard int maxEnemy[] = {5,7,12,20,30,15,50,30,40,60};//number of enimies per round int maxTowers=15;//maximum number of towers allowed static int money =2000,damPrice=600,ranPrice=350,towerPrice=700; //money = the intial ammount of money you start of with //damPrice is the price to increase the damage of a tower //ranPrice is the price to increase the range of a tower public void main(int cH,int mT,int mo,int dP,int rP,int tP,String path,int[] mE)//constructor 1 castleHealth=cH; maxTowers=mT; money=mo; damPrice=dP; ranPrice=rP; towerPrice=tP; String levelPath=path; maxEnemy = mE; buildLevel(); } public void main(int cH,int mT,String path)//basic constructor castleHealth=cH; maxTowers=mT; String levelPath=path; maxEnemy = mE; buildLevel(); } public void init(){ setSize(sqrSize*15+200,sqrSize*15);//set the size of the screen roadCol = new Color(255,216,0);//set the colors for the different objects startCol = new Color(0,38,255); finCol = new Color(255,0,0); selRoad = new Color(242,204,155);//selColor is the color of something when your mouse hovers over it selGrass = new Color(0,190,0); roadpic = getImage(getDocumentBase(),"images/road.jpg"); towerpic = getImage(getDocumentBase(),"images/tower.png"); backpic = getImage(getDocumentBase(),"images/grass.jpg"); levelPic = getImage(getDocumentBase(),"images/level.jpg"); e= new Enemy[maxEnemy.length][];//activates all of the enimies for (int r=0;r<e.length;r++) e[r] = new Enemy[maxEnemy[r]]; t= new Tower[maxTowers]; for (int i=0;i<t.length;i++) t[i]= new Tower();//activates all the towers for (int i=0;i<e.length; i++)//sets all of the enimies starting co ordinates for (int j=0;j<e[i].length;j++) e[i][j] = new Enemy(eStartX,eStartY,world); initButtons();//initialise all the buttons addMouseMotionListener(this); addMouseListener(this); }

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