corner case - Page 141 - Developer IT

Detect rotated rectangle collision

- by handyface

I'm trying to implement a script that detects whether two rotated rectangles collide for my game. I used the method explained in the following article for my implementation in Google Dart. 2D Rotated Rectangle Collision I tried to implement this code into my game. Basically from what I understood was that I have two rectangles, these two rectangles can produce four axis (two per rectangle) by subtracting adjacent corner coordinates. Then all the corners from both rectangles need to be projected onto each axis, then multiplying the coordinates of the projection by the axis coordinates (point.x*axis.x+point.y*axis.y) to make a scalar value and checking whether the range of both the rectangle's projections overlap. When all the axis have overlapping projections, there's a collision. First of all, I'm wondering whether my comprehension about this algorithm is correct. If so I'd like to get some pointers in where my implementation (written in Dart, which is very readable for people comfortable with C-syntax) goes wrong. Thanks!

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External Hard disk not workng on windows after I formatted it on Ubuntu

- by nav_jan

I formatted my Western Digital 500 Gb hard disk on Ubuntu 10.4 and now I want to use it on Windows 7 but it cannot detect it. I formatted it with FAT(applicable to all) option. I tried to Google this problem a bit and as suggested by one of the site i tried to format this drive with NTFS. Still windows cannot detect it. Drives in windows 7 is not a problem because I tried a different usb drive on it and it works. I can see the led of the drive glow when I connect it and I can also see remove drive safely option in lower right corner, but i cannot see any option in "my computer" to access the hard disk. I am new to Ubuntu. Any help is appreciated.

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SSMS Slow To Save

- by Bunch

When using SSMS 2008 I found it to be really slow when trying to save a file, even a small one with just some simple SELECT statements on it. The symptoms were the flashing save disk icons in the lower right corner and selecting the location to save in the Save File dialog would hang each time I picked a location (e.g. Libraries, a folder). This was the first I had seen anything like this where it was really, really slow. It ended up that a server had died last week and I was still mapping a drive to it. SSMS was still trying to connect to it causing the slow down (further information here and here). Once I removed that the save functionality worked like it should. Tags: SQL

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why doesnt ubuntu 13.04 prompt me for a password after suspend?

- by mark

I am on 13.04 and waking from suspend takes me straight to desktop without a password prompt even though it is set to ask for a password in the brightness and lock settings. Also I recently tried to lock my computer,going to the power menu in the top right corner and hitting lock,it does not do anything,I am still on the desktop..(just tried crtl alt l to lock,it does work) but not the way i did it though,but that is not important to me ,I need the password prompt after suspend.. Password prompts works only when booted from a shutdown...

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Random movement of wandering monsters in x & y axis in LibGDX

- by Vishal Kumar

I am making a simple top down RPG game in LibGDX. What I want is ... the enemies should wander here and there in x and y directions in certain interval so that it looks natural that they are guarding something. I spend several hours doing this but could not achieve what I want. After a long time of coding, I came with this code. But what I observed is when enemies come to an end of x or start of x or start of y or end of y of the map. It starts flickering for random intervals. Sometimes they remain nice, sometimes, they start flickering for long time. public class Enemy extends Sprite { public float MAX_VELOCITY = 0.05f; public static final int MOVING_LEFT = 0; public static final int MOVING_RIGHT = 1; public static final int MOVING_UP = 2; public static final int MOVING_DOWN = 3; public static final int HORIZONTAL_GUARD = 0; public static final int VERTICAL_GUARD = 1; public static final int RANDOM_GUARD = 2; private float startTime = System.nanoTime(); private static float SECONDS_TIME = 0; private boolean randomDecider; public int enemyType; public static final float width = 30 * World.WORLD_UNIT; public static final float height = 32 * World.WORLD_UNIT; public int state; public float stateTime; public boolean visible; public boolean dead; public Enemy(float x, float y, int enemyType) { super(x, y); state = MOVING_LEFT; this.enemyType = enemyType; stateTime = 0; visible = true; dead = false; boolean random = Math.random()>=0.5f ? true :false; if(enemyType == HORIZONTAL_GUARD){ if(random) velocity.x = -MAX_VELOCITY; else velocity.x = MAX_VELOCITY; } if(enemyType == VERTICAL_GUARD){ if(random) velocity.y = -MAX_VELOCITY; else velocity.y = MAX_VELOCITY; } if(enemyType == RANDOM_GUARD){ //if(random) //velocity.x = -MAX_VELOCITY; //else //velocity.y = MAX_VELOCITY; } } public void update(Enemy e, float deltaTime) { super.update(deltaTime); e.stateTime+= deltaTime; e.position.add(velocity); // This is for updating the Animation for Enemy Movement Direction. VERY IMPORTANT FOR REAL EFFECTS updateDirections(); //Here the various movement methods are called depending upon the type of the Enemy if(e.enemyType == HORIZONTAL_GUARD) guardHorizontally(); if(e.enemyType == VERTICAL_GUARD) guardVertically(); if(e.enemyType == RANDOM_GUARD) guardRandomly(); //quadrantMovement(e, deltaTime); } private void guardHorizontally(){ if(position.x <= 0){ velocity.x= MAX_VELOCITY; velocity.y= 0; } else if(position.x>= World.mapWidth-width){ velocity.x= -MAX_VELOCITY; velocity.y= 0; } } private void guardVertically(){ if(position.y<= 0){ velocity.y= MAX_VELOCITY; velocity.x= 0; } else if(position.y>= World.mapHeight- height){ velocity.y= -MAX_VELOCITY; velocity.x= 0; } } private void guardRandomly(){ if (System.nanoTime() - startTime >= 1000000000) { SECONDS_TIME++; if(SECONDS_TIME % 5==0) randomDecider = Math.random()>=0.5f ? true :false; if(SECONDS_TIME>=30) SECONDS_TIME =0; startTime = System.nanoTime(); } if(SECONDS_TIME <=30){ if(randomDecider && position.x >= 0) velocity.x= -MAX_VELOCITY; else{ if(position.x < World.mapWidth-width) velocity.x= MAX_VELOCITY; else velocity.x= -MAX_VELOCITY; } velocity.y =0; } else{ if(randomDecider && position.y >0) velocity.y= -MAX_VELOCITY; else velocity.y= MAX_VELOCITY; velocity.x =0; } /* //This is essential so as to keep the enemies inside the boundary of the Map if(position.x <= 0){ velocity.x= MAX_VELOCITY; //velocity.y= 0; } else if(position.x>= World.mapWidth-width){ velocity.x= -MAX_VELOCITY; //velocity.y= 0; } else if(position.y<= 0){ velocity.y= MAX_VELOCITY; //velocity.x= 0; } else if(position.y>= World.mapHeight- height){ velocity.y= -MAX_VELOCITY; //velocity.x= 0; } */ } private void updateDirections() { if(velocity.x > 0) state = MOVING_RIGHT; else if(velocity.x<0) state = MOVING_LEFT; else if(velocity.y>0) state = MOVING_UP; else if(velocity.y<0) state = MOVING_DOWN; } public Rectangle getBounds() { return new Rectangle(position.x, position.y, width, height); } private void quadrantMovement(Enemy e, float deltaTime) { int temp = e.getEnemyQuadrant(e.position.x, e.position.y); boolean random = Math.random()>=0.5f ? true :false; switch(temp){ case 1: velocity.x = MAX_VELOCITY; break; case 2: velocity.x = MAX_VELOCITY; break; case 3: velocity.x = -MAX_VELOCITY; break; case 4: velocity.x = -MAX_VELOCITY; break; default: if(random) velocity.x = MAX_VELOCITY; else velocity.y =-MAX_VELOCITY; } } public float getDistanceFromPoint(float p1,float p2){ Vector2 v1 = new Vector2(p1,p2); return position.dst(v1); } private int getEnemyQuadrant(float x, float y){ Rectangle enemyQuad = new Rectangle(x, y, 30, 32); if(ScreenQuadrants.getQuad1().contains(enemyQuad)) return 1; if(ScreenQuadrants.getQuad2().contains(enemyQuad)) return 2; if(ScreenQuadrants.getQuad3().contains(enemyQuad)) return 3; if(ScreenQuadrants.getQuad4().contains(enemyQuad)) return 4; return 0; } } Is there a better way of doing this. I am new to game development. I shall be very grateful to any help or reference.

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HDMI video connection cuts top and bottom borders of screen

- by Luis Alvarado

Ok this is an extension of another problem I had with a VGA connection and an Nvidia Geforce GT 440 card. Here is goes the explanation of this particular problem: I have a Soneview 32' TV. This TV has many connections including VGA (First reason I bought it), HDMI (Second reason but did not have a HDMI cable at that time) and DVI. I have had this TV for little over a month now, actually I had it to celebrate the release of Ubuntu 11.10 and started using it exactly on that date (I know too much fan there but hey, I like geek stuff). I started using it with the VGA cable. After 2 weeks I bought an Nvidia GT440 card. The previous 9500GT was working correctly with no problems whatsoever. I installed the GT440 and the first problem that I encountered using this latest card is mentioned here: Nvidia GT 440 black screen problem when loading lightdm greeter. The solution to this problem was to actually disconnect then connect again the VGA cable. This would result in the screen showing me the lightdm screen for my login. If I did not disconnect then connect the cable I could be there forever thinking that there is no video signal. I got tired of looking for answers that did not work and for solutions that made me literally have to install Ubuntu again. I just went and bought a HDMI cable and changed the VGA one for that one. It worked and I did not have to disconnect/connect the cable but now I have this problem when using any resolution. My normal resolution is 1920x1080 (This TV is 1080HD) so in VGA I could use this resolution with no problem, but on HDMI am getting the borders cut out. Here is a pic: As you can see from the PIC, the Launcher icons only show less than 50% of their witdh. Forget about the top and bottom parts, I can access them with the mouse but I can not visualize them in the screen. It is like it's outside of the TVs view. Basically there is like 20 to 30 pixels gone from all sides. I searched around and came to running xrand --verbose to see what it could detect from the TV. I got this: cyrex@cyrex:~$ xrandr --verbose xrandr: Failed to get size of gamma for output default Screen 0: minimum 320 x 175, current 1920 x 1080, maximum 1920 x 1080 default connected 1920x1080+0+0 (0x164) normal (normal) 0mm x 0mm Identifier: 0x163 Timestamp: 465485 Subpixel: unknown Clones: CRTC: 0 CRTCs: 0 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: 1920x1080 (0x164) 103.7MHz *current h: width 1920 start 0 end 0 total 1920 skew 0 clock 54.0KHz v: height 1080 start 0 end 0 total 1080 clock 50.0Hz 1920x1080 (0x165) 105.8MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 55.1KHz v: height 1080 start 0 end 0 total 1080 clock 51.0Hz 1920x1080 (0x166) 107.8MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 56.2KHz v: height 1080 start 0 end 0 total 1080 clock 52.0Hz 1920x1080 (0x167) 109.9MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 57.2KHz v: height 1080 start 0 end 0 total 1080 clock 53.0Hz 1920x1080 (0x168) 112.0MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 58.3KHz v: height 1080 start 0 end 0 total 1080 clock 54.0Hz 1920x1080 (0x169) 114.0MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 59.4KHz v: height 1080 start 0 end 0 total 1080 clock 55.0Hz 1680x1050 (0x16a) 98.8MHz h: width 1680 start 0 end 0 total 1680 skew 0 clock 58.8KHz v: height 1050 start 0 end 0 total 1050 clock 56.0Hz 1680x1050 (0x16b) 100.5MHz h: width 1680 start 0 end 0 total 1680 skew 0 clock 59.9KHz v: height 1050 start 0 end 0 total 1050 clock 57.0Hz 1600x1024 (0x16c) 95.0MHz h: width 1600 start 0 end 0 total 1600 skew 0 clock 59.4KHz v: height 1024 start 0 end 0 total 1024 clock 58.0Hz 1440x900 (0x16d) 76.5MHz h: width 1440 start 0 end 0 total 1440 skew 0 clock 53.1KHz v: height 900 start 0 end 0 total 900 clock 59.0Hz 1360x768 (0x171) 65.8MHz h: width 1360 start 0 end 0 total 1360 skew 0 clock 48.4KHz v: height 768 start 0 end 0 total 768 clock 63.0Hz 1360x768 (0x172) 66.8MHz h: width 1360 start 0 end 0 total 1360 skew 0 clock 49.2KHz v: height 768 start 0 end 0 total 768 clock 64.0Hz 1280x1024 (0x173) 85.2MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 66.6KHz v: height 1024 start 0 end 0 total 1024 clock 65.0Hz 1280x960 (0x176) 83.6MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 65.3KHz v: height 960 start 0 end 0 total 960 clock 68.0Hz 1280x960 (0x177) 84.8MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 66.2KHz v: height 960 start 0 end 0 total 960 clock 69.0Hz 1280x720 (0x178) 64.5MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 50.4KHz v: height 720 start 0 end 0 total 720 clock 70.0Hz 1280x720 (0x179) 65.4MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 51.1KHz v: height 720 start 0 end 0 total 720 clock 71.0Hz 1280x720 (0x17a) 66.4MHz h: width 1280 start 0 end 0 total 1280 skew 0 clock 51.8KHz v: height 720 start 0 end 0 total 720 clock 72.0Hz 1152x864 (0x17b) 72.7MHz h: width 1152 start 0 end 0 total 1152 skew 0 clock 63.1KHz v: height 864 start 0 end 0 total 864 clock 73.0Hz 1152x864 (0x17c) 73.7MHz h: width 1152 start 0 end 0 total 1152 skew 0 clock 63.9KHz v: height 864 start 0 end 0 total 864 clock 74.0Hz ....Many Resolutions later... 320x200 (0x1d1) 10.2MHz h: width 320 start 0 end 0 total 320 skew 0 clock 31.8KHz v: height 200 start 0 end 0 total 200 clock 159.0Hz 320x175 (0x1d2) 9.0MHz h: width 320 start 0 end 0 total 320 skew 0 clock 28.0KHz v: height 175 start 0 end 0 total 175 clock 160.0Hz 1920x1080 (0x1dd) 333.8MHz h: width 1920 start 0 end 0 total 1920 skew 0 clock 173.9KHz v: height 1080 start 0 end 0 total 1080 clock 161.0Hz If it helps, the Refresh Rate at 1920x1080 is 60. There is a flickering effect at this resolution using HDMI but not VGA which I imagine is related to the borders cut off issue am asking here. I have also done the following but this will only solve the problem on lower resolutions than 1920x1080 or on others TV (My father has a Sony TV where this problem is also solved): NVIDIA WAY Go to Nvidia-Settings and there will be an option that will have more features if a HDMI cable is connected. In the next pic the option is DFP-1 (CNDLCD) but this name changes depending on what device the PC is connected to: Uncheck Force Full GPU Scaling What this will do for resolutions LOWER than 1920x1080 (At least in my case) is solve the flickering problem and fix the borders cut by the monitor. Save to Xorg.conf file the changes made after changing to a resolution acceptable to your eyes. TV WAY If you TV has OSD Menu and this menu has options for scanning the screen resolution or auto adjusting to it, disable them. Specifically the option about SCAN. If you have an option for AV Mode disable it. Basically disable any option that needs to scan and scale the resolution. Test one by one. In the case of my father's TV this did it. In my case, the Nvidia solved it for lower resolutions. NOTE: In the case this is not solved in the next couple of weeks I will add this as the answer but take into consideration that the issue is still active with 1920x1080 resolutions.

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Accessing a Service from within an XNA Content Pipeline Extension

- by David Wallace

I need to allow my content pipeline extension to use a pattern similar to a factory. I start with a dictionary type: public delegate T Mapper<T>(MapFactory<T> mf, XElement d); public class MapFactory<T> { Dictionary<string, Mapper<T>> map = new Dictionary<string, Mapper<T>>(); public void Add(string s, Mapper<T> m) { map.Add(s, m); } public T Get(XElement xe) { if (xe == null) throw new ArgumentNullException( "Invalid document"); var key = xe.Name.ToString(); if (!map.ContainsKey(key)) throw new ArgumentException( key + " is not a valid key."); return map[key](this, xe); } public IEnumerable<T> GetAll(XElement xe) { if (xe == null) throw new ArgumentNullException( "Invalid document"); foreach (var e in xe.Elements()) { var val = e.Name.ToString(); if (map.ContainsKey(val)) yield return map[val](this, e); } } } Here is one type of object I want to store: public partial class TestContent { // Test type public string title; // Once test if true public bool once; // Parameters public Dictionary<string, object> args; public TestContent() { title = string.Empty; args = new Dictionary<string, object>(); } public TestContent(XElement xe) { title = xe.Name.ToString(); args = new Dictionary<string, object>(); xe.ParseAttribute("once", once); } } XElement.ParseAttribute is an extension method that works as one might expect. It returns a boolean that is true if successful. The issue is that I have many different types of tests, each of which populates the object in a way unique to the specific test. The element name is the key to MapFactory's dictionary. This type of test, while atypical, illustrates my problem. public class LogicTest : TestBase { string opkey; List<TestBase> items; public override bool Test(BehaviorArgs args) { if (items == null) return false; if (items.Count == 0) return false; bool result = items[0].Test(args); for (int i = 1; i < items.Count; i++) { bool other = items[i].Test(args); switch (opkey) { case "And": result &= other; if (!result) return false; break; case "Or": result |= other; if (result) return true; break; case "Xor": result ^= other; break; case "Nand": result = !(result & other); break; case "Nor": result = !(result | other); break; default: result = false; break; } } return result; } public static TestContent Build(MapFactory<TestContent> mf, XElement xe) { var result = new TestContent(xe); string key = "Or"; xe.GetAttribute("op", key); result.args.Add("key", key); var names = mf.GetAll(xe).ToList(); if (names.Count() < 2) throw new ArgumentException( "LogicTest requires at least two entries."); result.args.Add("items", names); return result; } } My actual code is more involved as the factory has two dictionaries, one that turns an XElement into a content type to write and another used by the reader to create the actual game objects. I need to build these factories in code because they map strings to delegates. I have a service that contains several of these factories. The mission is to make these factory classes available to a content processor. Neither the processor itself nor the context it uses as a parameter have any known hooks to attach an IServiceProvider or equivalent. Any ideas?

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Creating an SMF service for mercurial web server

- by Chris W Beal

I'm working on a project at the moment, which has a number of contributers. We're managing the project gate (which is stand alone) with mercurial. We want to have an easy way of seeing the changelog, so we can show management what is going on. Luckily mercurial provides a basic web server which allows you to see the changes, and drill in to change sets. This can be run as a daemon, but as it was running on our build server, every time it was rebooted, someone needed to remember to start the process again. This is of course a classic usage of SMF. Now I'm not an experienced person at writing SMF services, so it took me 1/2 an hour or so to figure it out the first time. But going forward I should know what I'm doing a bit better. I did reference this doc extensively. Taking a step back, the command to start the mercurial web server is $ hg serve -p <port number> -d So we somehow need to get SMF to run that command for us. In the simplest form, SMF services are really made up of two components. The manifest Usually lives in /var/svc/manifest somewhere Can be imported from any location The method Usually live in /lib/svc/method I simply put the script straight in that directory. Not very repeatable, but it worked Can take an argument of start, stop, or refresh Lets start with the manifest. This looks pretty complex, but all it's doing is describing the service name, the dependencies, the start and stop methods, and some properties. The properties can be by instance, that is to say I could have multiple hg serve processes handling different mercurial projects, on different ports simultaneously Here is the manifest I wrote. I stole extensively from the examples in the Documentation. So my manifest looks like this $ cat hg-serve.xml <?xml version="1.0"?> <!DOCTYPE service_bundle SYSTEM "/usr/share/lib/xml/dtd/service_bundle.dtd.1"> <service_bundle type='manifest' name='hg-serve'> <service name='application/network/hg-serve' type='service' version='1'> <dependency name='network' grouping='require_all' restart_on='none' type='service'> <service_fmri value='svc:/milestone/network:default' /> </dependency> <exec_method type='method' name='start' exec='/lib/svc/method/hg-serve %m' timeout_seconds='2' /> <exec_method type='method' name='stop' exec=':kill' timeout_seconds='2'> </exec_method> <instance name='project-gate' enabled='true'> <method_context> <method_credential user='root' group='root' /> </method_context> <property_group name='hg-serve' type='application'> <propval name='path' type='astring' value='/src/project-gate'/> <propval name='port' type='astring' value='9998' /> </property_group> </instance> <stability value='Evolving' /> <template> <common_name> <loctext xml:lang='C'>hg-serve</loctext> </common_name> <documentation> <manpage title='hg' section='1' /> </documentation> </template> </service> </service_bundle> So the only things I had to decide on in this are the service name "application/network/hg-serve" the start and stop methods (more of which later) and the properties. This is the information I need to pass to the start method script. In my case the port I want to start the web server on "9998", and the path to the source gate "/src/project-gate". These can be read in to the start method. So now lets look at the method scripts $ cat /lib/svc/method/hg-serve #!/sbin/sh # # # Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. # # Standard prolog # . /lib/svc/share/smf_include.sh if [ -z $SMF_FMRI ]; then echo "SMF framework variables are not initialized." exit $SMF_EXIT_ERR fi # # Build the command line flags # # Get the port and directory from the SMF properties port=`svcprop -c -p hg-serve/port $SMF_FMRI` dir=`svcprop -c -p hg-serve/path $SMF_FMRI` echo "$1" case "$1" in 'start') cd $dir /usr/bin/hg serve -d -p $port ;; *) echo "Usage: $0 {start|refresh|stop}" exit 1 ;; esac exit $SMF_EXIT_OK This is all pretty self explanatory, we read the port and directory using svcprop, and use those simply to run a command in the start case. We don't need to implement a stop case, as the manifest says to use "exec=':kill'for the stop method. Now all we need to do is import the manifest and start the service, but first verify the manifest # svccfg verify /path/to/hg-serve.xml If that doesn't give an error try importing it # svccfg import /path/to/hg-serve.xml If like me you originally put the hg-serve.xml file in /var/svc/manifest somewhere you'll get an error and told to restart the import service svccfg: Restarting svc:/system/manifest-import The manifest being imported is from a standard location and should be imported with the command : svcadm restart svc:/system/manifest-import # svcadm restart svc:/system/manifest-import and you're nearly done. You can look at the service using svcs -l # svcs -l hg-serve fmri svc:/application/network/hg-serve:project-gate name hg-serve enabled false state disabled next_state none state_time Thu May 31 16:11:47 2012 logfile /var/svc/log/application-network-hg-serve:project-gate.log restarter svc:/system/svc/restarter:default contract_id 15749 manifest /var/svc/manifest/network/hg/hg-serve.xml dependency require_all/none svc:/milestone/network:default (online) And look at the interesting properties # svcprop hg-serve hg-serve/path astring /src/project-gate hg-serve/port astring 9998 ...stuff deleted.... Then simply enable the service and if every things gone right, you can point your browser at http://server:9998 and get a nice graphical log of project activity. # svcadm enable hg-serve # svcs -l hg-serve fmri svc:/application/network/hg-serve:project-gate name hg-serve enabled true state online next_state none state_time Thu May 31 16:18:11 2012 logfile /var/svc/log/application-network-hg-serve:project-gate.log restarter svc:/system/svc/restarter:default contract_id 15858 manifest /var/svc/manifest/network/hg/hg-serve.xml dependency require_all/none svc:/milestone/network:default (online) None of this is rocket science, but a bit fiddly. Hence I thought I'd blog it. It might just be you see this in google and it clicks with you more than one of the many other blogs or how tos about it. Plus I can always refer back to it myself in 3 weeks, when I want to add another project to the server, and I've forgotten how to do it.

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Why Is Faulty Behaviour In The .NET Framework Not Fixed?

- by Alois Kraus

Here is the scenario: You have a Windows Form Application that calls a method via Invoke or BeginInvoke which throws exceptions. Now you want to find out where the error did occur and how the method has been called. Here is the output we do get when we call Begin/EndInvoke or simply Invoke The actual code that was executed was like this: private void cInvoke_Click(object sender, EventArgs e) { InvokingFunction(CallMode.Invoke); } [MethodImpl(MethodImplOptions.NoInlining)] void InvokingFunction(CallMode mode) { switch (mode) { case CallMode.Invoke: this.Invoke(new MethodInvoker(GenerateError)); The faulting method is called GenerateError which does throw a NotImplementedException exception and wraps it in a NotSupportedException. [MethodImpl(MethodImplOptions.NoInlining)] void GenerateError() { F1(); } private void F1() { try { F2(); } catch (Exception ex) { throw new NotSupportedException("Outer Exception", ex); } } private void F2() { throw new NotImplementedException("Inner Exception"); } It is clear that the method F2 and F1 did actually throw these exceptions but we do not see them in the call stack. If we directly call the InvokingFunction and catch and print the exception we can find out very easily how we did get into this situation. We see methods F1,F2,GenerateError and InvokingFunction directly in the stack trace and we see that actually two exceptions did occur. Here is for comparison what we get from Invoke/EndInvoke System.NotImplementedException: Inner Exception StackTrace: at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous) at System.Windows.Forms.Control.Invoke(Delegate method, Object[] args) at WindowsFormsApplication1.AppForm.InvokingFunction(CallMode mode) at WindowsFormsApplication1.AppForm.cInvoke_Click(Object sender, EventArgs e) at System.Windows.Forms.Control.OnClick(EventArgs e) at System.Windows.Forms.Button.OnClick(EventArgs e) The exception message is kept but the stack starts running from our Invoke call and not from the faulting method F2. We have therefore no clue where this exception did occur! The stack starts running at the method MarshaledInvoke because the exception is rethrown with the throw catchedException which resets the stack trace. That is bad but things are even worse because if previously lets say 5 exceptions did occur .NET will return only the first (innermost) exception. That does mean that we do not only loose the original call stack but all other exceptions and all data contained therein as well. It is a pity that MS does know about this and simply closes this issue as not important. Programmers will play a lot more around with threads than before thanks to TPL, PLINQ that do come with .NET 4. Multithreading is hyped quit a lot in the press and everybody wants to use threads. But if the .NET Framework makes it nearly impossible to track down the easiest UI multithreading issue I have a problem with that. The problem has been reported but obviously not been solved. .NET 4 Beta 2 did not have changed that dreaded GetBaseException call in MarshaledInvoke to return only the innermost exception of the complete exception stack. It is really time to fix this. WPF on the other hand does the right thing and wraps the exceptions inside a TargetInvocationException which makes much more sense. But Not everybody uses WPF for its daily work and Windows forms applications will still be used for a long time. Below is the code to repro the issues shown and how the exceptions can be rendered in a meaningful way. The default Exception.ToString implementation generates a hard to interpret stack if several nested exceptions did occur. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading; using System.Globalization; using System.Runtime.CompilerServices; namespace WindowsFormsApplication1 { public partial class AppForm : Form { enum CallMode { Direct = 0, BeginInvoke = 1, Invoke = 2 }; public AppForm() { InitializeComponent(); Thread.CurrentThread.CurrentUICulture = CultureInfo.InvariantCulture; Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(Application_ThreadException); } void Application_ThreadException(object sender, System.Threading.ThreadExceptionEventArgs e) { cOutput.Text = PrintException(e.Exception, 0, null).ToString(); } private void cDirectUnhandled_Click(object sender, EventArgs e) { InvokingFunction(CallMode.Direct); } private void cDirectCall_Click(object sender, EventArgs e) { try { InvokingFunction(CallMode.Direct); } catch (Exception ex) { cOutput.Text = PrintException(ex, 0, null).ToString(); } } private void cInvoke_Click(object sender, EventArgs e) { InvokingFunction(CallMode.Invoke); } private void cBeginInvokeCall_Click(object sender, EventArgs e) { InvokingFunction(CallMode.BeginInvoke); } [MethodImpl(MethodImplOptions.NoInlining)] void InvokingFunction(CallMode mode) { switch (mode) { case CallMode.Direct: GenerateError(); break; case CallMode.Invoke: this.Invoke(new MethodInvoker(GenerateError)); break; case CallMode.BeginInvoke: IAsyncResult res = this.BeginInvoke(new MethodInvoker(GenerateError)); this.EndInvoke(res); break; } } [MethodImpl(MethodImplOptions.NoInlining)] void GenerateError() { F1(); } private void F1() { try { F2(); } catch (Exception ex) { throw new NotSupportedException("Outer Exception", ex); } } private void F2() { throw new NotImplementedException("Inner Exception"); } StringBuilder PrintException(Exception ex, int identLevel, StringBuilder sb) { StringBuilder builtStr = sb; if( builtStr == null ) builtStr = new StringBuilder(); if( ex == null ) return builtStr; WriteLine(builtStr, String.Format("{0}: {1}", ex.GetType().FullName, ex.Message), identLevel); WriteLine(builtStr, String.Format("StackTrace: {0}", ShortenStack(ex.StackTrace)), identLevel + 1); builtStr.AppendLine(); return PrintException(ex.InnerException, ++identLevel, builtStr); } void WriteLine(StringBuilder sb, string msg, int identLevel) { foreach (string trimmedLine in SplitToLines(msg) .Select( (line) => line.Trim()) ) { for (int i = 0; i < identLevel; i++) sb.Append('\t'); sb.Append(trimmedLine); sb.AppendLine(); } } string ShortenStack(string stack) { int nonAppFrames = 0; // Skip stack frames not part of our app but include two foreign frames and skip the rest // If our stack frame is encountered reset counter to 0 return SplitToLines(stack) .Where((line) => { nonAppFrames = line.Contains("WindowsFormsApplication1") ? 0 : nonAppFrames + 1; return nonAppFrames < 3; }) .Select((line) => line) .Aggregate("", (current, line) => current + line + Environment.NewLine); } static char[] NewLines = Environment.NewLine.ToCharArray(); string[] SplitToLines(string str) { return str.Split(NewLines, StringSplitOptions.RemoveEmptyEntries); } } }

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Library like ENet, but for TCP?

- by Milo

I'm not looking to use boost::asio, it is overly complex for my needs. I'm building a game that is cross platform, for desktop, iPhone and Android. I found a library called ENet which is pretty much what I need, but it uses UDP which does not seem to support encryption and a few other things. Given that the game is an event driven card game, TCP seems like the right fit. However, all I have found is WINSOCK / berkley sockets and bost::asio. Here is a sample client server application with ENet: #include <enet/enet.h> #include <stdlib.h> #include <string> #include <iostream> class Host { ENetAddress address; ENetHost * server; ENetHost* client; ENetEvent event; public: Host() :server(NULL) { enet_initialize(); setupServer(); } void setupServer() { if(server) { enet_host_destroy(server); server = NULL; } address.host = ENET_HOST_ANY; /* Bind the server to port 1234. */ address.port = 1721; server = enet_host_create (& address /* the address to bind the server host to */, 32 /* allow up to 32 clients and/or outgoing connections */, 2 /* allow up to 2 channels to be used, 0 and 1 */, 0 /* assume any amount of incoming bandwidth */, 0 /* assume any amount of outgoing bandwidth */); } void daLoop() { while(true) { /* Wait up to 1000 milliseconds for an event. */ while (enet_host_service (server, & event, 5000) > 0) { ENetPacket * packet; switch (event.type) { case ENET_EVENT_TYPE_CONNECT: printf ("A new client connected from %x:%u.\n", event.peer -> address.host, event.peer -> address.port); /* Store any relevant client information here. */ event.peer -> data = "Client information"; /* Create a reliable packet of size 7 containing "packet\0" */ packet = enet_packet_create ("packet", strlen ("packet") + 1, ENET_PACKET_FLAG_RELIABLE); /* Extend the packet so and append the string "foo", so it now */ /* contains "packetfoo\0" */ enet_packet_resize (packet, strlen ("packetfoo") + 1); strcpy ((char*)& packet -> data [strlen ("packet")], "foo"); /* Send the packet to the peer over channel id 0. */ /* One could also broadcast the packet by */ /* enet_host_broadcast (host, 0, packet); */ enet_peer_send (event.peer, 0, packet); /* One could just use enet_host_service() instead. */ enet_host_flush (server); break; case ENET_EVENT_TYPE_RECEIVE: printf ("A packet of length %u containing %s was received from %s on channel %u.\n", event.packet -> dataLength, event.packet -> data, event.peer -> data, event.channelID); /* Clean up the packet now that we're done using it. */ enet_packet_destroy (event.packet); break; case ENET_EVENT_TYPE_DISCONNECT: printf ("%s disconected.\n", event.peer -> data); /* Reset the peer's client information. */ event.peer -> data = NULL; } } } } ~Host() { if(server) { enet_host_destroy(server); server = NULL; } atexit (enet_deinitialize); } }; class Client { ENetAddress address; ENetEvent event; ENetPeer *peer; ENetHost* client; public: Client() :peer(NULL) { enet_initialize(); setupPeer(); } void setupPeer() { client = enet_host_create (NULL /* create a client host */, 1 /* only allow 1 outgoing connection */, 2 /* allow up 2 channels to be used, 0 and 1 */, 57600 / 8 /* 56K modem with 56 Kbps downstream bandwidth */, 14400 / 8 /* 56K modem with 14 Kbps upstream bandwidth */); if (client == NULL) { fprintf (stderr, "An error occurred while trying to create an ENet client host.\n"); exit (EXIT_FAILURE); } /* Connect to some.server.net:1234. */ enet_address_set_host (& address, "192.168.2.13"); address.port = 1721; /* Initiate the connection, allocating the two channels 0 and 1. */ peer = enet_host_connect (client, & address, 2, 0); if (peer == NULL) { fprintf (stderr, "No available peers for initiating an ENet connection.\n"); exit (EXIT_FAILURE); } /* Wait up to 5 seconds for the connection attempt to succeed. */ if (enet_host_service (client, & event, 20000) > 0 && event.type == ENET_EVENT_TYPE_CONNECT) { std::cout << "Connection to some.server.net:1234 succeeded." << std::endl; } else { /* Either the 5 seconds are up or a disconnect event was */ /* received. Reset the peer in the event the 5 seconds */ /* had run out without any significant event. */ enet_peer_reset (peer); puts ("Connection to some.server.net:1234 failed."); } } void daLoop() { ENetPacket* packet; /* Create a reliable packet of size 7 containing "packet\0" */ packet = enet_packet_create ("backet", strlen ("backet") + 1, ENET_PACKET_FLAG_RELIABLE); /* Extend the packet so and append the string "foo", so it now */ /* contains "packetfoo\0" */ enet_packet_resize (packet, strlen ("backetfoo") + 1); strcpy ((char*)& packet -> data [strlen ("backet")], "foo"); /* Send the packet to the peer over channel id 0. */ /* One could also broadcast the packet by */ /* enet_host_broadcast (host, 0, packet); */ enet_peer_send (event.peer, 0, packet); /* One could just use enet_host_service() instead. */ enet_host_flush (client); while(true) { /* Wait up to 1000 milliseconds for an event. */ while (enet_host_service (client, & event, 1000) > 0) { ENetPacket * packet; switch (event.type) { case ENET_EVENT_TYPE_RECEIVE: printf ("A packet of length %u containing %s was received from %s on channel %u.\n", event.packet -> dataLength, event.packet -> data, event.peer -> data, event.channelID); /* Clean up the packet now that we're done using it. */ enet_packet_destroy (event.packet); break; } } } } ~Client() { atexit (enet_deinitialize); } }; int main() { std::string a; std::cin >> a; if(a == "host") { Host host; host.daLoop(); } else { Client c; c.daLoop(); } return 0; } I looked at some socket tutorials and they seemed a bit too low level. I just need something that abstracts away the platform (eg, no WINSOCKS) and that has basic ability to keep track of connected clients and send them messages. Thanks

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Changing CSS with jQuery syntax in Silverlight using jLight

- by Timmy Kokke

Lately I’ve ran into situations where I had to change elements or had to request a value in the DOM from Silverlight. jLight, which was introduced in an earlier article, can help with that. jQuery offers great ways to change CSS during runtime. Silverlight can access the DOM, but it isn’t as easy as jQuery. All examples shown in this article can be looked at in this online demo. The code can be downloaded here. Part 1: The easy stuff Selecting and changing properties is pretty straight forward. Setting the text color in all elements can be done using the following code: jQuery.Select("b").Css("color", "red"); The Css() method is an extension method on jQueryObject which is return by the jQuery.Select() method. The Css() method takes to parameters. The first is the Css style property. All properties used in Css can be entered in this string. The second parameter is the value you want to give the property. In this case the property is “color” and it is changed to “red”. To specify which element you want to select you can add a :selector parameter to the Select() method as shown in the next example. jQuery.Select("b:first").Css("font-family", "sans-serif"); The “:first” pseudo-class selector selects only the first element. This example changes the “font-family” property of the first element to “sans-serif”. To make use of intellisense in Visual Studio I’ve added a extension methods to help with the pseudo-classes. In the example below the “font-weight” of every “Even” <LI></LI> is set to “bold”. jQuery.Select("li".Even()).Css("font-weight", "bold"); Because the Css() extension method returns a jQueryObject it is possible to chain calls to Css(). The following example show setting the “color”, “background-color” and the “font-size” of all headers in one go. jQuery.Select(":header").Css("color", "#12FF70") .Css("background-color", "yellow") .Css("font-size", "25px"); Part 2: More complex stuff In only a few cases you need to change only one style property. More often you want to change an entire set op style properties all in one go. You could chain a lot of Css() methods together. A better way is to add a class to a stylesheet and define all properties in there. With the AddClass() method you can set a style class to a set of elements. This example shows how to add the “demostyle” class to all in the document. jQuery.Select("b").AddClass("demostyle"); Removing the class works in the same way: jQuery.Select("b").RemoveClass("demostyle"); jLight is build for interacting with to the DOM from Silverlight using jQuery. A jQueryObjectCss object can be used to define different sets of style properties in Silverlight. The over 60 most common Css style properties are defined in the jQueryObjectCss class. A string indexer can be used to access all style properties ( CssObject1[“background-color”] equals CssObject1.BackgroundColor). In the code below, two jQueryObjectCss objects are defined and instantiated. private jQueryObjectCss CssObject1; private jQueryObjectCss CssObject2; public Demo2() { CssObject1 = new jQueryObjectCss { BackgroundColor = "Lime", Color="Black", FontSize = "12pt", FontFamily = "sans-serif", FontWeight = "bold", MarginLeft = 150, LineHeight = "28px", Border = "Solid 1px #880000" }; CssObject2 = new jQueryObjectCss { FontStyle = "Italic", FontSize = "48", Color = "#225522" }; InitializeComponent(); } Now instead of chaining to set all different properties you can just pass one of the jQueryObjectCss objects to the Css() method. In this case all <LI></LI> elements are set to match this object. jQuery.Select("li").Css(CssObject1); When using the jQueryObjectCss objects chaining is still possible. In the following example all headers are given a blue backgroundcolor and the last is set to match CssObject2. jQuery.Select(":header").Css(new jQueryObjectCss{BackgroundColor = "Blue"}) .Eq(-1).Css(CssObject2); Part 3: The fun stuff Having Silverlight call JavaScript and than having JavaScript to call Silverlight requires a lot of plumbing code. Everything has to be registered and strings are passed back and forth to execute the JavaScript. jLight makes this kind of stuff so easy, it becomes fun to use. In a lot of situations jQuery can call a function to decide what to do, setting a style class based on complex expressions for example. jLight can do the same, but the callback methods are defined in Silverlight. This example calls the function() method for each <LI></LI> element. The callback method has to take a jQueryObject, an integer and a string as parameters. In this case jLight differs a bit from the actual jQuery implementation. jQuery uses only the index and the className parameters. A jQueryObject is added to make it simpler to access the attributes and properties of the element. If the text of the listitem starts with a ‘D’ or an ‘M’ the class is set. Otherwise null is returned and nothing happens. private void button1_Click(object sender, RoutedEventArgs e) { jQuery.Select("li").AddClass(function); } private string function(jQueryObject obj, int index, string className) { if (obj.Text[0] == 'D' || obj.Text[0] == 'M') return "demostyle"; return null; } The last thing I would like to demonstrate uses even more Silverlight and less jLight, but demonstrates the power of the combination. Animating a style property using a Storyboard with easing functions. First a dependency property is defined. In this case it is a double named Intensity. By handling the changed event the color is set using jQuery. public double Intensity { get { return (double)GetValue(IntensityProperty); } set { SetValue(IntensityProperty, value); } } public static readonly DependencyProperty IntensityProperty = DependencyProperty.Register("Intensity", typeof(double), typeof(Demo3), new PropertyMetadata(0.0, IntensityChanged)); private static void IntensityChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { var i = (byte)(double)e.NewValue; jQuery.Select("span").Css("color", string.Format("#{0:X2}{0:X2}{0:X2}", i)); } An animation has to be created. This code defines a Storyboard with one keyframe that uses a bounce ease as an easing function. The animation is set to target the Intensity dependency property defined earlier. private Storyboard CreateAnimation(double value) { Storyboard storyboard = new Storyboard(); var da = new DoubleAnimationUsingKeyFrames(); var d = new EasingDoubleKeyFrame { EasingFunction = new BounceEase(), KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1.0)), Value = value }; da.KeyFrames.Add(d); Storyboard.SetTarget(da, this); Storyboard.SetTargetProperty(da, new PropertyPath(Demo3.IntensityProperty)); storyboard.Children.Add(da); return storyboard; } Initially the Intensity is set to 128 which results in a gray color. When one of the buttons is pressed, a new animation is created an played. One to animate to black, and one to animate to white. public Demo3() { InitializeComponent(); Intensity = 128; } private void button2_Click(object sender, RoutedEventArgs e) { CreateAnimation(255).Begin(); } private void button3_Click(object sender, RoutedEventArgs e) { CreateAnimation(0).Begin(); } Conclusion As you can see jLight can make the life of a Silverlight developer a lot easier when accessing the DOM. Almost all jQuery functions that are defined in jLight use the same constructions as described above. I’ve tried to stay as close as possible to the real jQuery. Having JavaScript perform callbacks to Silverlight using jLight will be described in more detail in a future tutorial about AJAX or eventing.

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NSStream sockets missing data

- by Chris T.

I am trying to pull some sample data from FreeDB as a proof of concept, but I am having a tough time retrieving all of the data off the incoming stream (I am only getting the last bits for the final query listed here (if handshakeCode = 3) I think this may be something with the threading on the main runloop, but I am not sure. Odd thing is when the buffer size is larger than 1-2 bytes (which works as expected), I seem to be losing access to the data programmatically (the totalOutput variable on the first set of data is incomplete). I set up a packet capture, and it looks like those 1024 bytes are coming across the wire, but the app just isn't working with it. It looks like the next event is coming through and basically taking over. I tried using an NSLock to no avail as well. If I drop the buffer size down to 1 or 2, things seem to be reading just fine. This is probably obvious to someone who does this all the time, but this is my first foray into this with something I am familiar with, technology wise in other languages / platforms. The following code will show you what is happening. Run with the buffer set to 1024, and you will see a short final string, but once you set it to 1, you will see the amount of data I was expecting (I was even expecting it to be split, so that's not a big worry) #import <Foundation/Foundation.h> #import <Cocoa/Cocoa.h> //STACK OVERFLOW CODE: @interface stackoverflow : NSObject <NSStreamDelegate> { NSInputStream *iStream; NSOutputStream *oStream; int handshakeCode; NSString *selectedDiscId; NSString *selectedGenre; } -(void)getMatchesFromFreeDB; -(void)sendToOutputStream:(NSString*)command; @end @implementation stackoverflow -(void)getMatchesFromFreeDB { NSHost *host = [NSHost hostWithName:@"freedb.freedb.org"]; [NSStream getStreamsToHost:host port:8880 inputStream:&iStream outputStream:&oStream]; [iStream retain]; [oStream retain]; [iStream setDelegate:self]; [oStream setDelegate:self]; [iStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; [oStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; [iStream open]; [oStream open]; handshakeCode = 0; //not done any processing } -(void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode { switch(eventCode) { case NSStreamEventOpenCompleted: { NSLog(@"Stream open completed"); break; } case NSStreamEventHasBytesAvailable: { NSLog(@"Stream has bytes available"); if (aStream == iStream) { NSMutableString *totalOutput = [NSMutableString stringWithString:@""]; //read data uint8_t buffer[1024]; int len; while ([iStream hasBytesAvailable]) { len = [iStream read:buffer maxLength:sizeof(buffer)]; if (len 0) { NSString *output = [[NSString alloc] initWithBytes:buffer length:len encoding:NSUTF8StringEncoding]; //this could have also been put into an NSData object if (nil != output) { //append to the total output [totalOutput appendString:output]; } } } NSLog(@"OUTPUT , %i:\n\n%@", [totalOutput lengthOfBytesUsingEncoding:NSUTF8StringEncoding], totalOutput); NSArray *outputComponents = [totalOutput componentsSeparatedByString:@" "]; //Attempt to get handshake code, since we haven't done it yet: if (handshakeCode == 1) { //we are just getting the sign-on banner: //let's move on: handshakeCode = 2; } else if (handshakeCode == 2) { handshakeCode = [[outputComponents objectAtIndex:0] intValue]; if (handshakeCode == 200) { NSLog(@"---Handshake OK %i", handshakeCode); NSMutableString *query = [NSMutableString stringWithString:@"cddb query f3114b11 17 225 19915 36489 54850 69425 87025 103948 123242 136075 152817 178335 192850 211677 235104 262090 284882 308658 4430\n"]; handshakeCode = 3; [self sendToOutputStream:query]; } } else if (handshakeCode == 3) { //now, we are reading out the matches: if ([[outputComponents objectAtIndex:0] intValue] == 200) //found exact match: { NSLog(@"Found exact match"); selectedGenre = [outputComponents objectAtIndex:1] ; selectedDiscId = [outputComponents objectAtIndex:2]; if (selectedGenre && selectedDiscId) { //send off the request to get the entry: NSString *query = [NSString stringWithFormat:@"cddb read %@ %@\n", selectedGenre, selectedDiscId]; [self sendToOutputStream:query]; handshakeCode = 4; } } } } break; } case NSStreamEventEndEncountered: { NSLog(@"Stream event end encountered"); break; } case NSStreamEventErrorOccurred: { NSLog(@"Stream error occurred"); break; } case NSStreamEventHasSpaceAvailable: { NSLog(@"Stream has space available"); if (aStream == oStream) { if (handshakeCode == 0) { handshakeCode = 1; [self sendToOutputStream:@"cddb hello stackoverflow localhost.localdomain test .01BETA\n"]; } } break; } } } -(void)sendToOutputStream:(NSString*)command { const uint8_t *rawCommand = (const uint8_t *)[command UTF8String]; [oStream write:rawCommand maxLength:strlen(rawCommand)]; NSLog(@"Sent command: %@",command); } @end int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; stackoverflow *test = [[stackoverflow alloc] init]; [test getMatchesFromFreeDB]; NSRunLoop *runLoop = [NSRunLoop currentRunLoop]; [runLoop run]; [pool drain]; return 0; } Any help is much appreciated! Thanks

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The SSIS tuning tip that everyone misses

- by Rob Farley

I know that everyone misses this, because I’m yet to find someone who doesn’t have a bit of an epiphany when I describe this. When tuning Data Flows in SQL Server Integration Services, people see the Data Flow as moving from the Source to the Destination, passing through a number of transformations. What people don’t consider is the Source, getting the data out of a database. Remember, the source of data for your Data Flow is not your Source Component. It’s wherever the data is, within your database, probably on a disk somewhere. You need to tune your query to optimise it for SSIS, and this is what most people fail to do. I’m not suggesting that people don’t tune their queries – there’s plenty of information out there about making sure that your queries run as fast as possible. But for SSIS, it’s not about how fast your query runs. Let me say that again, but in bolder text: The speed of an SSIS Source is not about how fast your query runs. If your query is used in a Source component for SSIS, the thing that matters is how fast it starts returning data. In particular, those first 10,000 rows to populate that first buffer, ready to pass down the rest of the transformations on its way to the Destination. Let’s look at a very simple query as an example, using the AdventureWorks database: We’re picking the different Weight values out of the Product table, and it’s doing this by scanning the table and doing a Sort. It’s a Distinct Sort, which means that the duplicates are discarded. It'll be no surprise to see that the data produced is sorted. Obvious, I know, but I'm making a comparison to what I'll do later. Before I explain the problem here, let me jump back into the SSIS world... If you’ve investigated how to tune an SSIS flow, then you’ll know that some SSIS Data Flow Transformations are known to be Blocking, some are Partially Blocking, and some are simply Row transformations. Take the SSIS Sort transformation, for example. I’m using a larger data set for this, because my small list of Weights won’t demonstrate it well enough. Seven buffers of data came out of the source, but none of them could be pushed past the Sort operator, just in case the last buffer contained the data that would be sorted into the first buffer. This is a blocking operation. Back in the land of T-SQL, we consider our Distinct Sort operator. It’s also blocking. It won’t let data through until it’s seen all of it. If you weren’t okay with blocking operations in SSIS, why would you be happy with them in an execution plan? The source of your data is not your OLE DB Source. Remember this. The source of your data is the NCIX/CIX/Heap from which it’s being pulled. Picture it like this... the data flowing from the Clustered Index, through the Distinct Sort operator, into the SELECT operator, where a series of SSIS Buffers are populated, flowing (as they get full) down through the SSIS transformations. Alright, I know that I’m taking some liberties here, because the two queries aren’t the same, but consider the visual. The data is flowing from your disk and through your execution plan before it reaches SSIS, so you could easily find that a blocking operation in your plan is just as painful as a blocking operation in your SSIS Data Flow. Luckily, T-SQL gives us a brilliant query hint to help avoid this. OPTION (FAST 10000) This hint means that it will choose a query which will optimise for the first 10,000 rows – the default SSIS buffer size. And the effect can be quite significant. First let’s consider a simple example, then we’ll look at a larger one. Consider our weights. We don’t have 10,000, so I’m going to use OPTION (FAST 1) instead. You’ll notice that the query is more expensive, using a Flow Distinct operator instead of the Distinct Sort. This operator is consuming 84% of the query, instead of the 59% we saw from the Distinct Sort. But the first row could be returned quicker – a Flow Distinct operator is non-blocking. The data here isn’t sorted, of course. It’s in the same order that it came out of the index, just with duplicates removed. As soon as a Flow Distinct sees a value that it hasn’t come across before, it pushes it out to the operator on its left. It still has to maintain the list of what it’s seen so far, but by handling it one row at a time, it can push rows through quicker. Overall, it’s a lot more work than the Distinct Sort, but if the priority is the first few rows, then perhaps that’s exactly what we want. The Query Optimizer seems to do this by optimising the query as if there were only one row coming through: This 1 row estimation is caused by the Query Optimizer imagining the SELECT operation saying “Give me one row” first, and this message being passed all the way along. The request might not make it all the way back to the source, but in my simple example, it does. I hope this simple example has helped you understand the significance of the blocking operator. Now I’m going to show you an example on a much larger data set. This data was fetching about 780,000 rows, and these are the Estimated Plans. The data needed to be Sorted, to support further SSIS operations that needed that. First, without the hint. ...and now with OPTION (FAST 10000): A very different plan, I’m sure you’ll agree. In case you’re curious, those arrows in the top one are 780,000 rows in size. In the second, they’re estimated to be 10,000, although the Actual figures end up being 780,000. The top one definitely runs faster. It finished several times faster than the second one. With the amount of data being considered, these numbers were in minutes. Look at the second one – it’s doing Nested Loops, across 780,000 rows! That’s not generally recommended at all. That’s “Go and make yourself a coffee” time. In this case, it was about six or seven minutes. The faster one finished in about a minute. But in SSIS-land, things are different. The particular data flow that was consuming this data was significant. It was being pumped into a Script Component to process each row based on previous rows, creating about a dozen different flows. The data flow would take roughly ten minutes to run – ten minutes from when the data first appeared. The query that completes faster – chosen by the Query Optimizer with no hints, based on accurate statistics (rather than pretending the numbers are smaller) – would take a minute to start getting the data into SSIS, at which point the ten-minute flow would start, taking eleven minutes to complete. The query that took longer – chosen by the Query Optimizer pretending it only wanted the first 10,000 rows – would take only ten seconds to fill the first buffer. Despite the fact that it might have taken the database another six or seven minutes to get the data out, SSIS didn’t care. Every time it wanted the next buffer of data, it was already available, and the whole process finished in about ten minutes and ten seconds. When debugging SSIS, you run the package, and sit there waiting to see the Debug information start appearing. You look for the numbers on the data flow, and seeing operators going Yellow and Green. Without the hint, I’d sit there for a minute. With the hint, just ten seconds. You can imagine which one I preferred. By adding this hint, it felt like a magic wand had been waved across the query, to make it run several times faster. It wasn’t the case at all – but it felt like it to SSIS.

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Getting Paperclip to work in Rails

- by Danny McClelland

Hi Everyone, I have installed the Paperclip plugin to attempt to upload an avatar for my kase model. For some reason, the select the file button shows, and I can choose a file - but then when I click update the kase - it takes me to the show page, but the missing.png rather than the selected image. kase.rb class Kase < ActiveRecord::Base def self.all_latest find(:all, :order => 'created_at DESC', :limit => 5) end def self.search(search, page) paginate :per_page => 5, :page => page, :conditions => ['name like ?', "%#{search}%"], :order => 'name' end # Paperclip has_attached_file :avatar, :styles => { :medium => "300x300>", :thumb => "100x100>" } end kases_controller.rb # GET /kases/new # GET /kases/new.xml def new @kase = Kase.new respond_to do |format| format.html # new.html.erb format.xml { render :xml => @kase } end end new.html.erb <% content_for :header do -%> Cases <% end -% <% form_for(@kase) do |f| %> <%= f.error_messages %> <ul id="kases_new"> <li> <%= f.file_field :avatar %></li> <li>Job Ref.<%= f.text_field :jobno %></li> <li>Case Subject<%= f.text_field :casesubject %></li> <li>Transport<%= f.text_field :transport %></li> <li>Goods<%= f.text_field :goods %></li> <li>Date Instructed<%= f.date_select :dateinstructed %></li> <li>Case Status<%= f.select "kase_status", ['Active', 'On Hold', 'Archived'] %> </li> <li>Client Company Name<%= f.text_field :clientcompanyname %></li> <li>Client Company Address<%= f.text_field :clientcompanyaddress %></li> <li>Client Company Fax<%= f.text_field :clientcompanyfax %></li> <li>Case Handler Name<%= f.text_field :casehandlername %></li> <li>Case Handler Tel<%= f.text_field :casehandlertel %></li> <li>Case Handler Email<%= f.text_field :casehandleremail %></li> <li>Claimant Name<%= f.text_field :claimantname %></li> <li>Claimant Address<%= f.text_field :claimantaddress %></li> <li>Claimant Contact<%= f.text_field :claimantcontact %></li> <li>Claimant Tel<%= f.text_field :claimanttel %></li> <li>Claimant Mob<%= f.text_field :claimantmob %></li> <li>Claimant Email<%= f.text_field :claimantemail %></li> <li>Claimant URL<%= f.text_field :claimanturl %></li> <li>Comments<%= f.text_field :comments %></li> </ul> <div class="js_option"> <%= link_to_function "Show financial options.", "Element.show('finance_showhide');" %> </div> <div id="finance_showhide" style="display:none"> <ul id="kases_new_finance"> <li>Invoice Number<%= f.text_field :invoicenumber %></li> <li>Net Amount<%= f.text_field :netamount %></li> <li>VAT<%= f.text_field :vat %></li> <li>Gross Amount<%= f.text_field :grossamount %></li> <li>Date Closed<%= f.date_select :dateclosed %></li> <li>Date Paid<%= f.date_select :datepaid %></li> </ul> <div class="js_option"> <%= link_to_function "I'm confused! Hide financial options.", "Element.hide('finance_showhide');" %> </div> </div> <%= f.submit "Create" %> <% end %> <%= link_to 'Back', kases_path %> I have tried putting the <%= f.file_field :avatar % in it's own form on the same page, but that didn't make a difference. Thanks in advanced! Thanks, Danny

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Consuming the Amazon S3 service from a Win8 Metro Application

- by cibrax

As many of the existing Http APIs for Cloud Services, AWS also provides a set of different platform SDKs for hiding many of complexities present in the APIs. While there is a platform SDK for .NET, which is open source and available in C#, that SDK does not work in Win8 Metro Applications for the changes introduced in WinRT. WinRT offers a complete different set of APIs for doing I/O operations such as doing http calls or using cryptography for signing or encrypting data, two aspects that are absolutely necessary for consuming AWS. All the I/O APIs available as part of WinRT are asynchronous, and uses the TPL model for .NET applications (HTML and JavaScript Metro applications use a model based in promises, which is similar concept). In the case of S3, the http Authorization header is used for two purposes, authenticating clients and make sure the messages were not altered while they were in transit. For doing that, it uses a signature or hash of the message content and some of the headers using a symmetric key (That's just one of the available mechanisms). Windows Azure for example also uses the same mechanism in many of its APIs. There are three challenges that any developer working for first time in Metro will have to face to consume S3, the new WinRT APIs, the asynchronous nature of them and the complexity introduced for generating the Authorization header. Having said that, I decided to write this post with some of the gotchas I found myself trying to consume this Amazon service. 1. Generating the signature for the Authorization header All the cryptography APIs in WinRT are available under Windows.Security.Cryptography namespace. Many of operations available in these APIs uses the concept of buffers (IBuffer) for representing a chunk of binary data. As you will see in the example below, these buffers are mainly generated with the use of static methods in a WinRT class CryptographicBuffer available as part of the namespace previously mentioned. private string DeriveAuthToken(string resource, string httpMethod, string timestamp) { var stringToSign = string.Format("{0}\n" + "\n" + "\n" + "\n" + "x-amz-date:{1}\n" + "/{2}/", httpMethod, timestamp, resource); var algorithm = MacAlgorithmProvider.OpenAlgorithm("HMAC_SHA1"); var keyMaterial = CryptographicBuffer.CreateFromByteArray(Encoding.UTF8.GetBytes(this.secret)); var hmacKey = algorithm.CreateKey(keyMaterial); var signature = CryptographicEngine.Sign( hmacKey, CryptographicBuffer.CreateFromByteArray(Encoding.UTF8.GetBytes(stringToSign)) ); return CryptographicBuffer.EncodeToBase64String(signature); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The algorithm that determines the information or content you need to use for generating the signature is very well described as part of the AWS documentation. In this case, this method is generating a signature required for creating a new bucket. A HmacSha1 hash is computed using a secret or symetric key provided by AWS in the management console. 2. Sending an Http Request to the S3 service WinRT also ships with the System.Net.Http.HttpClient that was first introduced some months ago with ASP.NET Web API. This client provides a rich interface on top the traditional WebHttpRequest class, and also solves some of limitations found in this last one. There are a few things that don't work with a raw WebHttpRequest such as setting the Host header, which is something absolutely required for consuming S3. Also, HttpClient is more friendly for doing unit tests, as it receives a HttpMessageHandler as part of the constructor that can fake to emulate a real http call. This is how the code for consuming the service with HttpClient looks like, public async Task<S3Response> CreateBucket(string name, string region = null, params string[] acl) { var timestamp = string.Format("{0:r}", DateTime.UtcNow); var auth = DeriveAuthToken(name, "PUT", timestamp); var request = new HttpRequestMessage(HttpMethod.Put, "http://s3.amazonaws.com/"); request.Headers.Host = string.Format("{0}.s3.amazonaws.com", name); request.Headers.TryAddWithoutValidation("Authorization", "AWS " + this.key + ":" + auth); request.Headers.Add("x-amz-date", timestamp); var client = new HttpClient(); var response = await client.SendAsync(request); return new S3Response { Succeed = response.StatusCode == HttpStatusCode.OK, Message = (response.Content != null) ? await response.Content.ReadAsStringAsync() : null }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You will notice a few additional things in this code. By default, HttpClient validates the values for some well-know headers, and Authorization is one of them. It won't allow you to set a value with ":" on it, which is something that S3 expects. However, that's not a problem at all, as you can skip the validation by using the TryAddWithoutValidation method. Also, the code is heavily relying on the new async and await keywords to transform all the asynchronous calls into synchronous ones. In case you would want to unit test this code and faking the call to the real S3 service, you should have to modify it to inject a custom HttpMessageHandler into the HttpClient. The following implementation illustrates this concept, In case you would want to unit test this code and faking the call to the real S3 service, you should have to modify it to inject a custom HttpMessageHandler into the HttpClient. The following implementation illustrates this concept, public class FakeHttpMessageHandler : HttpMessageHandler { HttpResponseMessage response; public FakeHttpMessageHandler(HttpResponseMessage response) { this.response = response; } protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { var tcs = new TaskCompletionSource<HttpResponseMessage>(); tcs.SetResult(response); return tcs.Task; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You can use this handler for injecting any response while you are unit testing the code.

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Consuming the Amazon S3 service from a Win8 Metro Application

- by cibrax

As many of the existing Http APIs for Cloud Services, AWS also provides a set of different platform SDKs for hiding many of complexities present in the APIs. While there is a platform SDK for .NET, which is open source and available in C#, that SDK does not work in Win8 Metro Applications for the changes introduced in WinRT. WinRT offers a complete different set of APIs for doing I/O operations such as doing http calls or using cryptography for signing or encrypting data, two aspects that are absolutely necessary for consuming AWS. All the I/O APIs available as part of WinRT are asynchronous, and uses the TPL model for .NET applications (HTML and JavaScript Metro applications use a model based in promises, which is similar concept). In the case of S3, the http Authorization header is used for two purposes, authenticating clients and make sure the messages were not altered while they were in transit. For doing that, it uses a signature or hash of the message content and some of the headers using a symmetric key (That's just one of the available mechanisms). Windows Azure for example also uses the same mechanism in many of its APIs. There are three challenges that any developer working for first time in Metro will have to face to consume S3, the new WinRT APIs, the asynchronous nature of them and the complexity introduced for generating the Authorization header. Having said that, I decided to write this post with some of the gotchas I found myself trying to consume this Amazon service. 1. Generating the signature for the Authorization header All the cryptography APIs in WinRT are available under Windows.Security.Cryptography namespace. Many of operations available in these APIs uses the concept of buffers (IBuffer) for representing a chunk of binary data. As you will see in the example below, these buffers are mainly generated with the use of static methods in a WinRT class CryptographicBuffer available as part of the namespace previously mentioned. private string DeriveAuthToken(string resource, string httpMethod, string timestamp) { var stringToSign = string.Format("{0}\n" + "\n" + "\n" + "\n" + "x-amz-date:{1}\n" + "/{2}/", httpMethod, timestamp, resource); var algorithm = MacAlgorithmProvider.OpenAlgorithm("HMAC_SHA1"); var keyMaterial = CryptographicBuffer.CreateFromByteArray(Encoding.UTF8.GetBytes(this.secret)); var hmacKey = algorithm.CreateKey(keyMaterial); var signature = CryptographicEngine.Sign( hmacKey, CryptographicBuffer.CreateFromByteArray(Encoding.UTF8.GetBytes(stringToSign)) ); return CryptographicBuffer.EncodeToBase64String(signature); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The algorithm that determines the information or content you need to use for generating the signature is very well described as part of the AWS documentation. In this case, this method is generating a signature required for creating a new bucket. A HmacSha1 hash is computed using a secret or symetric key provided by AWS in the management console. 2. Sending an Http Request to the S3 service WinRT also ships with the System.Net.Http.HttpClient that was first introduced some months ago with ASP.NET Web API. This client provides a rich interface on top the traditional WebHttpRequest class, and also solves some of limitations found in this last one. There are a few things that don't work with a raw WebHttpRequest such as setting the Host header, which is something absolutely required for consuming S3. Also, HttpClient is more friendly for doing unit tests, as it receives a HttpMessageHandler as part of the constructor that can fake to emulate a real http call. This is how the code for consuming the service with HttpClient looks like, public async Task<S3Response> CreateBucket(string name, string region = null, params string[] acl) { var timestamp = string.Format("{0:r}", DateTime.UtcNow); var auth = DeriveAuthToken(name, "PUT", timestamp); var request = new HttpRequestMessage(HttpMethod.Put, "http://s3.amazonaws.com/"); request.Headers.Host = string.Format("{0}.s3.amazonaws.com", name); request.Headers.TryAddWithoutValidation("Authorization", "AWS " + this.key + ":" + auth); request.Headers.Add("x-amz-date", timestamp); var client = new HttpClient(); var response = await client.SendAsync(request); return new S3Response { Succeed = response.StatusCode == HttpStatusCode.OK, Message = (response.Content != null) ? await response.Content.ReadAsStringAsync() : null }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You will notice a few additional things in this code. By default, HttpClient validates the values for some well-know headers, and Authorization is one of them. It won't allow you to set a value with ":" on it, which is something that S3 expects. However, that's not a problem at all, as you can skip the validation by using the TryAddWithoutValidation method. Also, the code is heavily relying on the new async and await keywords to transform all the asynchronous calls into synchronous ones. In case you would want to unit test this code and faking the call to the real S3 service, you should have to modify it to inject a custom HttpMessageHandler into the HttpClient. The following implementation illustrates this concept, In case you would want to unit test this code and faking the call to the real S3 service, you should have to modify it to inject a custom HttpMessageHandler into the HttpClient. The following implementation illustrates this concept, public class FakeHttpMessageHandler : HttpMessageHandler { HttpResponseMessage response; public FakeHttpMessageHandler(HttpResponseMessage response) { this.response = response; } protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { var tcs = new TaskCompletionSource<HttpResponseMessage>(); tcs.SetResult(response); return tcs.Task; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You can use this handler for injecting any response while you are unit testing the code.

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RIF PRD: Presentation syntax issues

- by Charles Young

Over Christmas I got to play a bit with the W3C RIF PRD and came across a few issues which I thought I would record for posterity. Specifically, I was working on a grammar for the presentation syntax using a GLR grammar parser tool (I was using the current CTP of ‘M’ (MGrammer) and Intellipad – I do so hope the MS guys don’t kill off M and Intellipad now they have dropped the other parts of SQL Server Modelling). I realise that the presentation syntax is non-normative and that any issues with it do not therefore compromise the standard. However, presentation syntax is useful in its own right, and it would be great to iron out any issues in a future revision of the standard. The main issues are actually not to do with the grammar at all, but rather with the ‘running example’ in the RIF PRD recommendation. I started with the code provided in Example 9.1. There are several discrepancies when compared with the EBNF rules documented in the standard. Broadly the problems can be categorised as follows: · Parenthesis mismatch – the wrong number of parentheses are used in various places. For example, in GoldRule, the RHS of the rule (the ‘Then’) is nested in the LHS (‘the If’). In NewCustomerAndWidgetRule, the RHS is orphaned from the LHS. Together with additional incorrect parenthesis, this leads to orphanage of UnknownStatusRule from the entire Document. · Invalid use of parenthesis in ‘Forall’ constructs. Parenthesis should not be used to enclose formulae. Removal of the invalid parenthesis gave me a feeling of inconsistency when comparing formulae in Forall to formulae in If. The use of parenthesis is not actually inconsistent in these two context, but in an If construct it ‘feels’ as if you are enclosing formulae in parenthesis in a LISP-like fashion. In reality, the parenthesis is simply being used to group subordinate syntax elements. The fact that an If construct can contain only a single formula as an immediate child adds to this feeling of inconsistency. · Invalid representation of compact URIs (CURIEs) in the context of Frame productions. In several places the URIs are not qualified with a namespace prefix (‘ex1:’). This conflicts with the definition of CURIEs in the RIF Datatypes and Built-Ins 1.0 document. Here are the productions: CURIE ::= PNAME_LN | PNAME_NS PNAME_LN ::= PNAME_NS PN_LOCAL PNAME_NS ::= PN_PREFIX? ':' PN_LOCAL ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* PN_CHARS)? PN_CHARS ::= PN_CHARS_U | '-' | [0-9] | #x00B7 | [#x0300-#x036F] | [#x203F-#x2040] PN_CHARS_U ::= PN_CHARS_BASE | '_' PN_CHARS_BASE ::= [A-Z] | [a-z] | [#x00C0-#x00D6] | [#x00D8-#x00F6] | [#x00F8-#x02FF] | [#x0370-#x037D] | [#x037F-#x1FFF] | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF] | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD] | [#x10000-#xEFFFF] PN_PREFIX ::= PN_CHARS_BASE ((PN_CHARS|'.')* PN_CHARS)? The more I look at CURIEs, the more my head hurts! The RIF specification allows prefixes and colons without local names, which surprised me. However, the CURIE Syntax 1.0 working group note specifically states that this form is supported…and then promptly provides a syntactic definition that seems to preclude it! However, on (much) deeper inspection, it appears that ‘ex1:’ (for example) is allowed, but would really represent a ‘fragment’ of the ‘reference’, rather than a prefix! Ouch! This is so completely ambiguous that it surely calls into question the whole CURIE specification. In any case, RIF does not allow local names without a prefix. · Missing ‘External’ specifiers for built-in functions and predicates. The EBNF specification enforces this for terms within frames, but does not appear to enforce (what I believe is) the correct use of External on built-in predicates. In any case, the running example only specifies ‘External’ once on the predicate in UnknownStatusRule. External() is required in several other places. · The List used on the LHS of UnknownStatusRule is comma-delimited. This is not supported by the EBNF definition. Similarly, the argument list of pred:list-contains is illegally comma-delimited. · Unnecessary use of conjunction around a single formula in DiscountRule. This is strictly legal in the EBNF, but redundant. All the above issues concern the presentation syntax used in the running example. There are a few minor issues with the grammar itself. Note that Michael Kiefer stated in his paper “Rule Interchange Format: The Framework” that: “The presentation syntax of RIF … is an abstract syntax and, as such, it omits certain details that might be important for unambiguous parsing.” · The grammar cannot differentiate unambiguously between strategies and priorities on groups. A processor is forced to resolve this by detecting the use of IRIs and integers. This could easily be fixed in the grammar. · The grammar cannot unambiguously parse the ‘->’ operator in frames. Specifically, ‘-’ characters are allowed in PN_LOCAL names and hence a parser cannot determine if ‘status->’ is (‘status’ ‘->’) or (‘status-’ ‘>’). One way to fix this is to amend the PN_LOCAL production as follows: PN_LOCAL ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* ((PN_CHARS)-('-')))? However, unilaterally changing the definition of this production, which is defined in the SPARQL Query Language for RDF specification, makes me uncomfortable. · I assume that the presentation syntax is case-sensitive. I couldn’t find this stated anywhere in the documentation, but function/predicate names do appear to be documented as being case-sensitive. · The EBNF does not specify whitespace handling. A couple of productions (RULE and ACTION_BLOCK) are crafted to enforce the use of whitespace. This is not necessary. It seems inconsistent with the rest of the specification and can cause parsing issues. In addition, the Const production exhibits whitespaces issues. The intention may have been to disallow the use of whitespace around ‘^^’, but any direct implementation of the EBNF will probably allow whitespace between ‘^^’ and the SYMSPACE. Of course, I am being a little nit-picking about all this. On the whole, the EBNF translated very smoothly and directly to ‘M’ (MGrammar) and proved to be fairly complete. I have encountered far worse issues when translating other EBNF specifications into usable grammars. I can’t imagine there would be any difficulty in implementing the same grammar in Antlr, COCO/R, gppg, XText, Bison, etc. A general observation, which repeats a point made above, is that the use of parenthesis in the presentation syntax can feel inconsistent and un-intuitive. It isn’t actually inconsistent, but I think the presentation syntax could be improved by adopting braces, rather than parenthesis, to delimit subordinate syntax elements in a similar way to so many programming languages. The familiarity of braces would communicate the structure of the syntax more clearly to people like me. If braces were adopted, parentheses could be retained around ‘var (frame | ‘new()’) constructs in action blocks. This use of parenthesis feels very LISP-like, and I think that this is my issue. It’s as if the presentation syntax represents the deformed love-child of LISP and C. In some places (specifically, action blocks), parenthesis is used in a LISP-like fashion. In other places it is used like braces in C. I find this quite confusing. Here is a corrected version of the running example (Example 9.1) in compliant presentation syntax: Document( Prefix( ex1 <http://example.com/2009/prd2> ) (* ex1:CheckoutRuleset *) Group rif:forwardChaining ( (* ex1:GoldRule *) Group 10 ( Forall ?customer such that And(?customer # ex1:Customer ?customer[ex1:status->"Silver"]) (Forall ?shoppingCart such that ?customer[ex1:shoppingCart->?shoppingCart] (If Exists ?value (And(?shoppingCart[ex1:value->?value] External(pred:numeric-greater-than-or-equal(?value 2000)))) Then Do(Modify(?customer[ex1:status->"Gold"]))))) (* ex1:DiscountRule *) Group ( Forall ?customer such that ?customer # ex1:Customer (If Or( ?customer[ex1:status->"Silver"] ?customer[ex1:status->"Gold"]) Then Do ((?s ?customer[ex1:shoppingCart-> ?s]) (?v ?s[ex1:value->?v]) Modify(?s [ex1:value->External(func:numeric-multiply (?v 0.95))])))) (* ex1:NewCustomerAndWidgetRule *) Group ( Forall ?customer such that And(?customer # ex1:Customer ?customer[ex1:status->"New"] ) (If Exists ?shoppingCart ?item (And(?customer[ex1:shoppingCart->?shoppingCart] ?shoppingCart[ex1:containsItem->?item] ?item # ex1:Widget ) ) Then Do( (?s ?customer[ex1:shoppingCart->?s]) (?val ?s[ex1:value->?val]) (?voucher ?customer[ex1:voucher->?voucher]) Retract(?customer[ex1:voucher->?voucher]) Retract(?voucher) Modify(?s[ex1:value->External(func:numeric-multiply(?val 0.90))])))) (* ex1:UnknownStatusRule *) Group ( Forall ?customer such that ?customer # ex1:Customer (If Not(Exists ?status (And(?customer[ex1:status->?status] External(pred:list-contains(List("New" "Bronze" "Silver" "Gold") ?status)) ))) Then Do( Execute(act:print(External(func:concat("New customer: " ?customer)))) Assert(?customer[ex1:status->"New"])))) ) ) I hope that helps someone out there :-)

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JSP Precompilation for ADF Applications

- by Duncan Mills

A question that comes up from time to time, particularly in relation to build automation, is how to best pre-compile the .jspx and .jsff files in an ADF application. Thus ensuring that the app is ready to run as soon as it's installed into WebLogic. In the normal run of things, the first poor soul to hit a page pays the price and has to wait a little whilst the JSP is compiled into a servlet. Everyone else subsequently gets a free lunch. So it's a reasonable thing to want to do... Let Me List the Ways So forth to Google (other search engines are available)... which lead me to a fairly old article on WLDJ - Removing Performance Bottlenecks Through JSP Precompilation. Technololgy wise, it's somewhat out of date, but the one good point that it made is that it's really not very useful to try and use the precompile option in the weblogic.xml file. That's a really good observation - particularly if you're trying to integrate a pre-compile step into a Hudson Continuous Integration process. That same article mentioned an alternative approach for programmatic pre-compilation using weblogic.jspc. This seemed like a much more useful approach for a CI environment. However, weblogic.jspc is now obsoleted by weblogic.appc so we'll use that instead. Thanks to Steve for the pointer there. And So To APPC APPC has documentation - always a great place to start, and supports usage both from Ant via the wlappc task and from the command line using the weblogic.appc command. In my testing I took the latter approach. Usage, as the documentation will show you, is superficially pretty simple. The nice thing here, is that you can pass an existing EAR file (generated of course using OJDeploy) and that EAR will be updated in place with the freshly compiled servlet classes created from the JSPs. Appc takes care of all the unpacking, compiling and re-packing of the EAR for you. Neat. So we're done right...? Not quite. The Devil is in the Detail OK so I'm being overly dramatic but it's not all plain sailing, so here's a short guide to using weblogic.appc to compile a simple ADF application without pain. Information You'll Need The following is based on the assumption that you have a stand-alone WLS install with the Application Development Runtime installed and a suitable ADF enabled domain created. This could of course all be run off of a JDeveloper install as well 1. Your Weblogic home directory. Everything you need is relative to this so make a note. In my case it's c:\builds\wls_ps4. 2. Next deploy your EAR as normal and have a peek inside it using your favourite zip management tool. First of all look at the weblogic-application.xml inside the EAR /META-INF directory. Have a look for any library references. Something like this: <library-ref> <library-name>adf.oracle.domain</library-name> </library-ref> Make a note of the library ref (adf.oracle.domain in this case) , you'll need that in a second. 3. Next open the nested WAR file within the EAR and then have a peek inside the weblogic.xml file in the /WEB-INF directory. Again make a note of the library references. 4. Now start the WebLogic as per normal and run the WebLogic console app (e.g. http://localhost:7001/console). In the Domain Structure navigator, select Deployments. 5. For each of the libraries you noted down drill into the library definition and make a note of the .war, .ear or .jar that defines the library. For example, in my case adf.oracle.domain maps to "C:\ builds\ WLS_PS4\ oracle_common\ modules\ oracle. adf. model_11. 1. 1\ adf. oracle. domain. ear". Note the extra spaces that are salted throughout this string as it is displayed in the console - just to make it annoying, you'll have to strip these out. 6. Finally you'll need the location of the adfsharebean.jar. We need to pass this on the classpath for APPC so that the ADFConfigLifeCycleCallBack listener can be found. In a more complex app of your own you may need additional classpath entries as well. Now we're ready to go, and it's a simple matter of applying the information we have gathered into the relevant command line arguments for the utility A Simple CMD File to Run APPC Here's the stub .cmd file I'm using on Windows to run this. @echo offREM Stub weblogic.appc Runner setlocal set WLS_HOME=C:\builds\WLS_PS4 set ADF_LIB_ROOT=%WLS_HOME%\oracle_common\modulesset COMMON_LIB_ROOT=%WLS_HOME%\wlserver_10.3\common\deployable-libraries set ADF_WEBAPP=%ADF_LIB_ROOT%\oracle.adf.view_11.1.1\adf.oracle.domain.webapp.war set ADF_DOMAIN=%ADF_LIB_ROOT%\oracle.adf.model_11.1.1\adf.oracle.domain.ear set JSTL=%COMMON_LIB_ROOT%\jstl-1.2.war set JSF=%COMMON_LIB_ROOT%\jsf-1.2.war set ADF_SHARE=%ADF_LIB_ROOT%\oracle.adf.share_11.1.1\adfsharembean.jar REM Set up the WebLogic Environment so appc can be found call %WLS_HOME%\wlserver_10.3\server\bin\setWLSEnv.cmd CLS REM Now compile away!java weblogic.appc -verbose -library %ADF_WEBAPP%,%ADF_DOMAIN%,%JSTL%,%JSF% -classpath %ADF_SHARE% %1 endlocal Running the above on a target ADF .ear file will zip through and create all of the relevant compiled classes inside your nested .war file in the \WEB-INF\classes\jsp_servlet\ directory (but don't take my word for it, run it and take a look!) And So... In the immortal words of the Pet Shop Boys, Was It Worth It? Well, here's where you'll have to do your own testing. In my case here, with a simple ADF application, pre-compilation shaved an non-scientific "3 Elephants" off of the initial page load time for the first access of each page. That's a pretty significant payback for such a simple step to add into your CI process, so why not give it a go.

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Oracle OpenWorld 2013 – Wrap up by Sven Bernhardt

- by JuergenKress

OOW 2013 is over and we’re heading home, so it is time to lean back and reflecting about the impressions we have from the conference. First of all: OOW was great! It was a pleasure to be a part of it. As already mentioned in our last blog article: It was the biggest OOW ever. Parallel to the conference the America’s Cup took place in San Francisco and the Oracle Team America won. Amazing job by the team and again congratulations from our side Back to the conference. The main topics for us are: Oracle SOA / BPM Suite 12c Adaptive Case management (ACM) Big Data Fast Data Cloud Mobile Below we will go a little more into detail, what are the key takeaways regarding the mentioned points: Oracle SOA / BPM Suite 12c During the five days at OOW, first details of the upcoming major release of Oracle SOA Suite 12c and Oracle BPM Suite 12c have been introduced. Some new key features are: Managed File Transfer (MFT) for transferring big files from a source to a target location Enhanced REST support by introducing a new REST binding Introduction of a generic cloud adapter, which can be used to connect to different cloud providers, like Salesforce Enhanced analytics with BAM, which has been totally reengineered (BAM Console now also runs in Firefox!) Introduction of templates (OSB pipelines, component templates, BPEL activities templates) EM as a single monitoring console OSB design-time integration into JDeveloper (Really great!) Enterprise modeling capabilities in BPM Composer These are only a few points from what is coming with 12c. We are really looking forward for the new realese to come out, because this seems to be really great stuff. The suite becomes more and more integrated. From 10g to 11g it was an evolution in terms of developing SOA-based applications. With 12c, Oracle continues it’s way – very impressive. Adaptive Case Management Another fantastic topic was Adaptive Case Management (ACM). The Oracle PMs did a great job especially at the demo grounds in showing the upcoming Case Management UI (will be available in 11g with the next BPM Suite MLR Patch), the roadmap and the differences between traditional business process modeling. They have been very busy during the conference because a lot of partners and customers have been interested Big Data Big Data is one of the current hype themes. Because of huge data amounts from different internal or external sources, the handling of these data becomes more and more challenging. Companies have a need for analyzing the data to optimize their business. The challenge is here: the amount of data is growing daily! To store and analyze the data efficiently, it is necessary to have a scalable and flexible infrastructure. Here it is important that hardware and software are engineered to work together. Therefore several new features of the Oracle Database 12c, like the new in-memory option, have been presented by Larry Ellison himself. From a hardware side new server machines like Fujitsu M10 or new processors, such as Oracle’s new M6-32 have been announced. The performance improvements, when using one of these hardware components in connection with the improved software solutions were really impressive. For more details about this, please take look at our previous blog post. Regarding Big Data, Oracle also introduced their Big Data architecture, which consists of: Oracle Big Data Appliance that is preconfigured with Hadoop Oracle Exdata which stores a huge amount of data efficently, to achieve optimal query performance Oracle Exalytics as a fast and scalable Business analytics system Analysis of the stored data can be performed using SQL, by streaming the data directly from Hadoop to an Oracle Database 12c. Alternatively the analysis can be directly implemented in Hadoop using “R”. In addition Oracle BI Tools can be used to analyze the data. Fast Data Fast Data is a complementary approach to Big Data. A huge amount of mostly unstructured data comes in via different channels with a high frequency. The analysis of these data streams is also important for companies, because the incoming data has to be analyzed regarding business-relevant patterns in real-time. Therefore these patterns must be identified efficiently and performant. To do so, in-memory grid solutions in combination with Oracle Coherence and Oracle Event Processing demonstrated very impressive how efficient real-time data processing can be. One example for Fast Data solutions that was shown during the OOW was the analysis of twitter streams regarding customer satisfaction. The feeds with negative words like “bad” or “worse” have been filtered and after a defined treshold has been reached in a certain timeframe, a business event was triggered. Cloud Another key trend in the IT market is of course Cloud Computing and what it means for companies and their businesses. Oracle announced their Cloud strategy and vision – companies can focus on their real business while all of the applications are available via Cloud. This also includes Oracle Database or Oracle Weblogic, so that companies can also build, deploy and run their own applications within the cloud. Three different approaches have been introduced: Infrastructure as a Service (IaaS) Platform as a Service (PaaS) Software as a Service (SaaS) Using the IaaS approach only the infrastructure components will be managed in the Cloud. Customers will be very flexible regarding memory, storage or number of CPUs because those parameters can be adjusted elastically. The PaaS approach means that besides the infrastructure also the platforms (such as databases or application servers) necessary for running applications will be provided within the Cloud. Here customers can also decide, if installation and management of these infrastructure components should be done by Oracle. The SaaS approach describes the most complete one, hence all applications a company uses are managed in the Cloud. Oracle is planning to provide all of their applications, like ERP systems or HR applications, as Cloud services. In conclusion this seems to be a very forward-thinking strategy, which opens up new possibilities for customers to manage their infrastructure and applications in a flexible, scalable and future-oriented manner. As you can see, our OOW days have been very very interresting. We collected many helpful informations for our projects. The new innovations presented at the confernce are great and being part of this was even greater! We are looking forward to next years’ conference! Links: http://www.oracle.com/openworld/index.html http://thecattlecrew.wordpress.com/2013/09/23/first-impressions-from-oracle-open-world-2013 SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Mix Forum Technorati Tags: cattleCrew,Sven Bernhard,OOW2013,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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finding numbers of days between two date to make a dynamic columns

- by Chandradyani

Dear all, I have a select query that currently produces the following results: DoctorName Team 1 2 3 4 5 6 7 ... 31 Visited dr. As A x x ... 2 times dr. Sc A x ... 1 times dr. Gh B x ... 1 times dr. Nd C ... x 1 times Using the following query: DECLARE @startDate = '1/1/2010', @enddate = '1/31/2010' SELECT d.doctorname, t.teamname, MAX(CASE WHEN ca.visitdate = 1 THEN 'x' ELSE NULL END) AS 1, MAX(CASE WHEN ca.visitdate = 2 THEN 'x' ELSE NULL END) AS 2, MAX(CASE WHEN ca.visitdate = 3 THEN 'x' ELSE NULL END) AS 3, ... MAX(CASE WHEN ca.visitdate = 31 THEN 'x' ELSE NULL END) AS 31, COUNT(*) AS visited FROM CACTIVITY ca JOIN DOCTOR d ON d.id = ca.doctorid JOIN TEAM t ON t.id = ca.teamid WHERE ca.visitdate BETWEEN @startdate AND @enddate GROUP BY d.doctorname, t.teamname the problem is I want to make the column of date are dynamic for example if ca.visitdate BETWEEN '2/1/2012' AND '2/29/2012' so the result will be : DoctorName Team 1 2 3 4 5 6 7 ... 29 Visited dr. As A x x ... 2 times dr. Sc A x ... 1 times dr. Gh B x ... 1 times dr. Nd C ... x 1 times Can somebody help me how to get numbers of days between two date and help me revised the query so it can looping MAX(CASE WHEN ca.visitdate = 1 THEN 'x' ELSE NULL END) AS 1 as many as numbers of days? Please please

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Reasoner Conversion Problems:

- by Annalyne

I have this code right here in Java and I wanted to translate it in C++, but I had some problems going: this is the java code: import java.io.*; import java.util.*; public class ClueReasoner { private int numPlayers; private int playerNum; private int numCards; private SATSolver solver; private String caseFile = "cf"; private String[] players = {"sc", "mu", "wh", "gr", "pe", "pl"}; private String[] suspects = {"mu", "pl", "gr", "pe", "sc", "wh"}; private String[] weapons = {"kn", "ca", "re", "ro", "pi", "wr"}; private String[] rooms = {"ha", "lo", "di", "ki", "ba", "co", "bi", "li", "st"}; private String[] cards; public ClueReasoner() { numPlayers = players.length; // Initialize card info cards = new String[suspects.length + weapons.length + rooms.length]; int i = 0; for (String card : suspects) cards[i++] = card; for (String card : weapons) cards[i++] = card; for (String card : rooms) cards[i++] = card; numCards = i; // Initialize solver solver = new SATSolver(); addInitialClauses(); } private int getPlayerNum(String player) { if (player.equals(caseFile)) return numPlayers; for (int i = 0; i < numPlayers; i++) if (player.equals(players[i])) return i; System.out.println("Illegal player: " + player); return -1; } private int getCardNum(String card) { for (int i = 0; i < numCards; i++) if (card.equals(cards[i])) return i; System.out.println("Illegal card: " + card); return -1; } private int getPairNum(String player, String card) { return getPairNum(getPlayerNum(player), getCardNum(card)); } private int getPairNum(int playerNum, int cardNum) { return playerNum * numCards + cardNum + 1; } public void addInitialClauses() { // TO BE IMPLEMENTED AS AN EXERCISE // Each card is in at least one place (including case file). for (int c = 0; c < numCards; c++) { int[] clause = new int[numPlayers + 1]; for (int p = 0; p <= numPlayers; p++) clause[p] = getPairNum(p, c); solver.addClause(clause); } // If a card is one place, it cannot be in another place. // At least one card of each category is in the case file. // No two cards in each category can both be in the case file. } public void hand(String player, String[] cards) { playerNum = getPlayerNum(player); // TO BE IMPLEMENTED AS AN EXERCISE } public void suggest(String suggester, String card1, String card2, String card3, String refuter, String cardShown) { // TO BE IMPLEMENTED AS AN EXERCISE } public void accuse(String accuser, String card1, String card2, String card3, boolean isCorrect) { // TO BE IMPLEMENTED AS AN EXERCISE } public int query(String player, String card) { return solver.testLiteral(getPairNum(player, card)); } public String queryString(int returnCode) { if (returnCode == SATSolver.TRUE) return "Y"; else if (returnCode == SATSolver.FALSE) return "n"; else return "-"; } public void printNotepad() { PrintStream out = System.out; for (String player : players) out.print("\t" + player); out.println("\t" + caseFile); for (String card : cards) { out.print(card + "\t"); for (String player : players) out.print(queryString(query(player, card)) + "\t"); out.println(queryString(query(caseFile, card))); } } public static void main(String[] args) { ClueReasoner cr = new ClueReasoner(); String[] myCards = {"wh", "li", "st"}; cr.hand("sc", myCards); cr.suggest("sc", "sc", "ro", "lo", "mu", "sc"); cr.suggest("mu", "pe", "pi", "di", "pe", null); cr.suggest("wh", "mu", "re", "ba", "pe", null); cr.suggest("gr", "wh", "kn", "ba", "pl", null); cr.suggest("pe", "gr", "ca", "di", "wh", null); cr.suggest("pl", "wh", "wr", "st", "sc", "wh"); cr.suggest("sc", "pl", "ro", "co", "mu", "pl"); cr.suggest("mu", "pe", "ro", "ba", "wh", null); cr.suggest("wh", "mu", "ca", "st", "gr", null); cr.suggest("gr", "pe", "kn", "di", "pe", null); cr.suggest("pe", "mu", "pi", "di", "pl", null); cr.suggest("pl", "gr", "kn", "co", "wh", null); cr.suggest("sc", "pe", "kn", "lo", "mu", "lo"); cr.suggest("mu", "pe", "kn", "di", "wh", null); cr.suggest("wh", "pe", "wr", "ha", "gr", null); cr.suggest("gr", "wh", "pi", "co", "pl", null); cr.suggest("pe", "sc", "pi", "ha", "mu", null); cr.suggest("pl", "pe", "pi", "ba", null, null); cr.suggest("sc", "wh", "pi", "ha", "pe", "ha"); cr.suggest("wh", "pe", "pi", "ha", "pe", null); cr.suggest("pe", "pe", "pi", "ha", null, null); cr.suggest("sc", "gr", "pi", "st", "wh", "gr"); cr.suggest("mu", "pe", "pi", "ba", "pl", null); cr.suggest("wh", "pe", "pi", "st", "sc", "st"); cr.suggest("gr", "wh", "pi", "st", "sc", "wh"); cr.suggest("pe", "wh", "pi", "st", "sc", "wh"); cr.suggest("pl", "pe", "pi", "ki", "gr", null); cr.printNotepad(); cr.accuse("sc", "pe", "pi", "bi", true); } } how can I convert this? there are too many errors I get. for my C++ code (as a commentor asked for) #include <iostream> #include <cstdlib> #include <string> using namespace std; void Scene_Reasoner() { int numPlayer; int playerNum; int cardNum; string filecase = "Case: "; string players [] = {"sc", "mu", "wh", "gr", "pe", "pl"}; string suspects [] = {"mu", "pl", "gr", "pe", "sc", "wh"}; string weapons [] = {"kn", "ca", "re", "ro", "pi", "wr"}; string rooms[] = {"ha", "lo", "di", "ki", "ba", "co", "bi", "li", "st"}; string cards [0]; }; void Scene_Reason_Base () { numPlayer = players.length; // Initialize card info cards = new String[suspects.length + weapons.length + rooms.length]; int i = 0; for (String card : suspects) cards[i++] = card; for (String card : weapons) cards[i++] = card; for (String card : rooms) cards[i++] = card; cardNum = i; }; private int getCardNum (string card) { for (int i = 0; i < numCards; i++) if (card.equals(cards[i])) return i; cout << "Illegal card: " + card <<endl; return -1; }; private int getPairNum(String player, String card) { return getPairNum(getPlayerNum(player), getCardNum(card)); }; private int getPairNum(int playerNum, int cardNum) { return playerNum * numCards + cardNum + 1; }; int main () { return 0; }

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GCC ICE -- alternative function syntax, variadic templates and tuples

- by Marc H.

(Related to C++0x, How do I expand a tuple into variadic template function arguments?.) The following code (see below) is taken from this discussion. The objective is to apply a function to a tuple. I simplified the template parameters and modified the code to allow for a return value of generic type. While the original code compiles fine, when I try to compile the modified code with GCC 4.4.3, g++ -std=c++0x main.cc -o main GCC reports an internal compiler error (ICE) with the following message: main.cc: In function ‘int main()’: main.cc:53: internal compiler error: in tsubst_copy, at cp/pt.c:10077 Please submit a full bug report, with preprocessed source if appropriate. See <file:///usr/share/doc/gcc-4.4/README.Bugs> for instructions. Question: Is the code correct? or is the ICE triggered by illegal code? // file: main.cc #include <tuple> // Recursive case template<unsigned int N> struct Apply_aux { template<typename F, typename T, typename... X> static auto apply(F f, const T& t, X... x) -> decltype(Apply_aux<N-1>::apply(f, t, std::get<N-1>(t), x...)) { return Apply_aux<N-1>::apply(f, t, std::get<N-1>(t), x...); } }; // Terminal case template<> struct Apply_aux<0> { template<typename F, typename T, typename... X> static auto apply(F f, const T&, X... x) -> decltype(f(x...)) { return f(x...); } }; // Actual apply function template<typename F, typename T> auto apply(F f, const T& t) -> decltype(Apply_aux<std::tuple_size<T>::value>::apply(f, t)) { return Apply_aux<std::tuple_size<T>::value>::apply(f, t); } // Testing #include <string> #include <iostream> int f(int p1, double p2, std::string p3) { std::cout << "int=" << p1 << ", double=" << p2 << ", string=" << p3 << std::endl; return 1; } int g(int p1, std::string p2) { std::cout << "int=" << p1 << ", string=" << p2 << std::endl; return 2; } int main() { std::tuple<int, double, char const*> tup(1, 2.0, "xxx"); std::cout << apply(f, tup) << std::endl; std::cout << apply(g, std::make_tuple(4, "yyy")) << std::endl; } Remark: If I hardcode the return type in the recursive case (see code), then everything is fine. That is, substituting this snippet for the recursive case does not trigger the ICE: // Recursive case (hardcoded return type) template<unsigned int N> struct Apply_aux { template<typename F, typename T, typename... X> static int apply(F f, const T& t, X... x) { return Apply_aux<N-1>::apply(f, t, std::get<N-1>(t), x...); } }; Alas, this is an incomplete solution to the original problem.

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Why can't my main class see the array in my calender class

- by Rocky Celltick Eadie

This is a homework problem. I'm already 5 days late and can't figure out what I'm doing wrong.. this is my 1st semester in Java and my first post on this site Here is the assignment.. Create a class called Calendar. The class should contain a variable called events that is a String array. The array should be created to hold 5 elements. Use a constant value to specify the array size. Do not hard code the array size. Initialize the array in the class constructor so that each element contains the string “ – No event planned – “. The class should contain a method called CreateEvent. This method should accept a String argument that contains a one-word user event and an integer argument that represents the day of the week. Monday should be represented by the number 1 and Friday should be represented by the number 5. Populate the events array with the event info passed into the method. Although the user will input one-word events, each event string should prepend the following string to each event: event_dayAppoinment: (where event_day is the day of the week) For example, if the user enters 1 and “doctor” , the first array element should read: Monday Appointment: doctor If the user enters 2 and “PTA” , the second array element should read: Tuesday Appointment: PTA Write a driver program (in a separate class) that creates and calls your Calendar class. Then use a loop to gather user input. Ask for the day (as an integer) and then ask for the event (as a one word string). Pass the integer and string to the Calendar object’s CreateEvent method. The user should be able enter 0 – 5 events. If the user enters -1, the loop should exit and your application should print out all the events in a tabular format. Your program should not allow the user to enter invalid values for the day of the week. Any input other than 1 – 5 or -1 for the day of the week would be considered invalid. Notes: When obtaining an integer from the user, you will need to use the nextInt() method on your Scanner object. When obtaining a string from a user, you will need to use the next() method on your Scanner object. Here is my code so far.. //DRIVER CLASS /** * * @author Rocky */ //imports scanner import java.util.Scanner; //begin class driver public class driver { /** * @paramargs the command line arguments */ //begin main method public static void main(String[] args) { //initiates scanner Scanner userInput = new Scanner (System.in); //declare variables int dayOfWeek; String userEvent; //creates object for calender class calendercalenderObject = new calender(); //user prompt System.out.println("Enter day of week for your event in the following format:"); System.out.println("Enter 1 for Monday"); System.out.println("Enter 2 for Tuesday"); System.out.println("Enter 3 for Wednsday"); System.out.println("Enter 4 for Thursday"); System.out.println("Enter 5 for Friday"); System.out.println("Enter -1 to quit"); //collect user input dayOfWeek = userInput.nextInt(); //user prompt System.out.println("Please type in the name of your event"); //collect user input userEvent = userInput.next(); //begin while loop while (dayOfWeek != -1) { //test for valid day of week if ((dayOfWeek>=1) && (dayOfWeek<=5)){ //calls createEvent method in calender class and passes 2 variables calenderObject.createEvent(userEvent,dayOfWeek); } else { //error message System.out.println("You have entered an invalid number"); //user prompts System.out.println("Press -1 to quit or enter another day"); System.out.println("Enter 1 for Monday"); System.out.println("Enter 2 for Tuesday"); System.out.println("Enter 3 for Wednsday"); System.out.println("Enter 4 for Thursday"); System.out.println("Enter 5 for Friday"); System.out.println("Enter -1 to quit"); //collect user input dayOfWeek = userInput.nextInt(); //end data validity test } //end while loop } //prints array to screen int i=0; for (i=0;i<events.length;i++){ System.out.println(events[i]); } //end main method } } /** * * @author Rocky */ //imports scanner import java.util.Scanner; //begin calender class public class calender { //creates events array String[] events = new String[5]; //begin calender class constructor public calender() { //Initializes array String[] events = {"-No event planned-","-No event planned-","-No event planned-","-No event planned-","-No event planned-"}; //end calender class constructor } //begin createEvent method public String[] createEvent (String userEvent, int dayOfWeek){ //Start switch test switch (dayOfWeek){ case 1: events[0] = ("Monday Appoinment:") + userEvent; break; case 2: events[1] = ("Tuesday Appoinment:") + userEvent; break; case 3: events[2] = ("WednsdayAppoinment:") + userEvent; break; case 4: events[3] = ("Thursday Appoinment:") + userEvent; break; case 5: events[4] = ("Friday Appoinment:") + userEvent; break; default: break; //End switch test } //returns events array return events; //end create event method } //end calender class }

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D2K to OA Framework Transition

- by PRajkumar

What is the difference between D2K form and OA Framework? It is a very innocent but important question for someone that desires to make transition from D2K to OA Framework. I hope you have already read and implemented OA Framework Getting Started. I will re-visit my own experience of implementing HelloWorld program in "OA Framework". When I implemented HelloWorld a year ago, I had no clue as to what I was doing & why I was doing those steps. I merely copied the steps from Oracle Tutorial without understanding them. Hence in this blog, I will try to explain in simple manner the meaning of OA Framework HelloWorld Program and compare the steps to D2K form [where possible]. To keep things simple, only basics will be discussed. Following key Steps were needed for HelloWorld Step 1 Create a new Workspace and a new Project as dictated by Oracle's tutorial. When defining project, you will specify a default package, which in this case was oracle.apps.ak.hello This means the following: - ak is the short name of the Application in Oracle [means fnd_applications.short_name] hello is the name of your project Step 2 Next, you will create a OA Page within hello project Think OA Page as the fmx file itself in D2K. I am saying so because this page gets attached to the form function. This page will be created within hello project, hence the package name oracle.apps.ak.hello.webui Note the webui, it is a convention to have page in webui, means this page represents the Web User Interface You will assign the default AM [OAApplicationModule]. Think of AM "Connection Manager" and "Transaction State Manager" for your page I can't co-relate this to anything in D2k, as there is no concept of Connection Pooling and that D2k is not stateless. Reason being that as soon as you kick off a D2K Form, it connects to a single session of Oracle and sticks to that single Oracle database session. So is not the case in OAF, hence AM is needed. Step 3 You create Region within the Page. · Region is what will store your fields. Text input fields will be of type messageTextInput. Think of Canvas in D2K. You can have nested regions. Stacked Canvas in D2K comes the closest to this component of OA Framework Step 4 Add a button to one of the nested regions The itemStyle should be submitButton, in case you want the page to be submitted when this button is clicked There is no WHEN-BUTTON-PRESSED trigger in OAF. In Framework, you will add a controller java code to handle events like Form Submit button clicks. JDeveloper generates the default code for you. Primarily two functions [should I call methods] will be created processRequest [for UI Rendering Handling] and processFormRequest Think of processRequest as WHEN-NEW-FORM-INSTANCE, though processRequest is very restrictive. Note What is the difference between processRequest and processFormRequest? These two methods are available in the Default Controller class that gets created. processFormRequest This method is commonly used to react/respond to the event that has taken place, for example click of a button. Some examples are if(oapagecontext.getParameter("Cancel") != null) (Do your processing for Cancellation/ Rollback) if(oapagecontext.getParameter("Submit") != null) (Do your validations and commit here) if(oapagecontext.getParameter("Update") != null) (Do your validations and commit here) In the above three examples, you could be calling oapagecontext.forwardImmediately to re-direct the page navigation to some other page if needed. processRequest In this method, usually page rendering related code is written. Effectively, each GUI component is a bean that gets initialised during processRequest. Those who are familiar with D2K forms, something like pre-query may be written in this method. Step 5 In the controller to access the value in field "HelloName" the command is String userContent = pageContext.getParameter("HelloName"); In D2k, we used :block.field. In OAFramework, at submission of page, all the field values get passed into to OAPageContext object. Use getParameter to access the field value To set the value of the field, use OAMessageTextInputBean field HelloName = (OAMessageTextInputBean)webBean.findChildRecursive("HelloName"); fieldHelloName.setText(pageContext,"Setting the default value" ); Note when setting field value in controller: Note 1. Do not set the value in processFormRequest Note 2. If the field comes from View Object, then do not use setText in controller Note 3. For control fields [that are not based on View Objects], you can use setText to assign values in processRequest method Lets take some notes to expand beyond the HelloWorld Project Note 1 In D2K-forms we sort of created a Window, attached to Canvas, and then fields within that Canvas. However in OA Framework, think of Page being fmx/Window, think of Region being a Canvas, and fields being within Regions. This is not a formal/accurate understanding of analogy between D2k and Framework, but is close to being logical. Note 2 In D2k, your Forms fmb file was compiled to fmx. It was fmx file that was deployed on mid-tier. In case of OAF, your OA Page is nothing but a XML file. We call this MDS [meta data]. Whatever name you give to "Page" in OAF, an XML file of the same name gets created. This xml file must then be loaded into database by using XML Importer command. Note 3 Apart from MDS XML file, almost everything else is merely deployed to your mid-tier. Usually this is underneath $JAVA_TOP/oracle/apps/../.. All java files will go underneath java top/oracle/apps/../.. etc. Note 4 When building tutorial, ignore the steps for setting "Attribute Sets". These are not mandatory. Oracle might just have developed their tutorials without including these. Think of these like Visual Attributes of D2K forms Note 5 Controller is where you will write any java code in OA Framework. You can create a Controller per Page or have a different Controller for each of the Regions with the same Page. Note 6 In the method processFormRequest of the Controller, you can access the values of the page by using notation pageContext.getParameter("<fieldname here>"). This method processFormRequest is executed when the OAF Screen/Page is submitted by click of a button. Note 7 Inside the controller, all the Database Related interactions for example interaction with View Objects happen via Application Module. But why so? Because Application Module Manages the transaction state of the Application. OAApplicationModuleImpl oaapplicationmoduleimpl = OAApplicationModuleImpl)oapagecontext.getApplicationModule(oawebbean); OADBTransaction oadbtransaction = OADBTransaction)oaapplicationmoduleimpl.getDBTransaction(); Note 8 In D2K, we have control block or a block based on database view. Similarly, in OA Framework, if the field does not have view Object attached, then it is like a control field. Hence in HelloWorld example, field HelloName is a control field [in D2K terminology]. A view Object can either be based on a view/table, synonym or on a SQL statement. Note 9 I wish to access the fields in multi record block that is based on view Object. Can I do this in Controller? Sure you can. To traverse through those records, do the below · Get the reference to the View Object using (OAViewObject)oapagecontext.getApplicationModule(oawebbean).findViewObject("VO Name Here") · Loop through the records in View Objects using count returned from oaviewobject.getFetchedRowCount() · For each record, fetch the value of the fields within the loop as oracle.jbo.Row row = oaviewobject.getRowAtRangeIndex(loop index here); (String)row.getAttribute("Column name of VO here ");

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A Bite With No Teeth–Demystifying Non-Compete Clauses

- by D'Arcy Lussier

*DISCLAIMER: I am not a lawyer and this post in no way should be considered legal advice. I’m also in Canada, so references made are to Canadian court cases. I received a signed letter the other day, a reminder from my previous employer about some clauses associated with my employment and entry into an employee stock purchase program. So since this is in effect for the next 12 months, I guess I’m not starting that new job tomorrow. I’m kidding of course. How outrageous, how presumptuous, pompous, and arrogant that a company – any company – would actually place these conditions upon an employee. And yet, this is not uncommon. Especially in the IT industry, we see time and again similar wording in our employment agreements. But…are these legal? Is there any teeth behind the threat of the bite? Luckily, the answer seems to be ‘No’. I want to highlight two cases that support this. The first is Lyons v. Multari. In a nutshell, Dentist hires younger Dentist to be an associate. In their short, handwritten agreement, a non-compete clause was written stating “Protective Covenant. 3 yrs. – 5mi” (meaning you can’t set up shop within 5 miles for 3 years). Well, the young dentist left and did start an oral surgery office within 5 miles and within 3 years. Off to court they go! The initial judge sided with the older dentist, but on appeal it was overturned. Feel free to read the transcript of the decision here, but let me highlight one portion from section [19]: The general rule in most common law jurisdictions is that non-competition clauses in employment contracts are void. The sections following [19] explain further, and discuss Elsley v. J.G. Collins Insurance Agency Ltd. and its impact on Canadian law in this regard. The second case is Winnipeg Livestock Sales Ltd. v. Plewman. Desmond Plewman is an auctioneer, and worked at Winnipeg Livestock Sales. Part of his employment agreement was that he could not work for a competitor for 18 months if he left the company. Well, he left, and took up an important role in a competing company. The case went to court and as with Lyons v. Multari, the initial judge found in favour of the plaintiffs. Also as in the first case, that was overturned on appeal. Again, read through the transcript of the decision, but consider section [28]: In other words, even though Plewman has a great deal of skill as an auctioneer, Winnipeg Livestock has no proprietary interest in his professional skill and experience, even if they were acquired during his time working for Winnipeg Livestock. Thus, Winnipeg Livestock has the burden of establishing that it has a legitimate proprietary interest requiring protection. On this key question there is little evidence before the Court. The record discloses that part of Plewman’s job was to “mingle with the … crowd” and to telephone customers and prospective customers about future prospects for the sale of livestock. It may seem reasonable to assume that Winnipeg Livestock has a legitimate proprietary interest in its customer connections; but there is no evidence to indicate that there is any significant degree of “customer loyalty” in the business, as opposed to customers making choices based on other considerations such as cost, availability and the like. So are there any incidents where a non-compete can actually be valid? Yes, and these are considered “exceptional” cases, meaning that the situation meets certain circumstances. Michael Carabash has a great blog series discussing the above mentioned cases as well as the difference between a non-compete and non-solicit agreement. He talks about the exceptional criteria: In summary, the authorities reveal that the following circumstances will generally be relevant in determining whether a case is an “exceptional” one so that a general non-competition clause will be found to be reasonable: - The length of service with the employer. - The amount of personal service to clients. - Whether the employee dealt with clients exclusively, or on a sustained or recurring basis. - Whether the knowledge about the client which the employee gained was of a confidential nature, or involved an intimate knowledge of the client’s particular needs, preferences or idiosyncrasies. - Whether the nature of the employee’s work meant that the employee had influence over clients in the sense that the clients relied upon the employee’s advice, or trusted the employee. - If competition by the employee has already occurred, whether there is evidence that clients have switched their custom to him, especially without direct solicitation. - The nature of the business with respect to whether personal knowledge of the clients’ confidential matters is required. - The nature of the business with respect to the strength of customer loyalty, how clients are “won” and kept, and whether the clientele is a recurring one. - The community involved and whether there were clientele yet to be exploited by anyone. I close this blog post with a final quote, one from Zvulony & Co’s blog post on this subject. Again, all of this is not official legal advice, but I think we can see what all these sources are pointing towards. To answer my earlier question, there’s no teeth behind the threat of the bite. In light of this list, and the decisions in Lyons and Orlan, it is reasonably certain that in most employment situations a non-competition clause will be ineffective in protecting an employer from a departing employee who wishes to compete in the same business. The Courts have been relatively consistent in their position that if a non-solicitation clause can protect an employer’s interests, then a non-competition clause is probably unreasonable. Employers (or their solicitors) should avoid the inclination to draft restrictive covenants in broad, catch-all language. Or in other words, when drafting a restrictive covenant – take only what you need! D

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