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• Should I use a regular server instead of AWS?

  - by Jon Ramvi

  Reading about and using the Amazon Web Services, I'm not really able to grasp how to use it correctly. Sorry about the long question: I have a EC2 instance which mostly does the work of a web server (apache for file sharing and Tomcat with Play Framework for the web app). As it's a web server, the instance is running 24/7. It just came to my attention that the data on the EC2 instance is non persistent. This means I lose my database and files if it's stopped. But I guess it also means my server settings and installed applications are lost as they are just files in the same way as the other data. This means that I will either have to rewrite the whole app to use amazon CloudDB or write some code which stores the db on S3 and make my own AMI with the correct applications installed and configured. Or can this be quick-fixed by using EBS somehow? My question is 1. is my understanding of aws is correct? and 2. is it's worth it? It could be a possibility to just set up a regular dedicated server where everything is persistent, as you would expect. Would love to have the scaleability of aws though..

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• setBit java method using bit shifting and hexadecimal code - question

  - by somewhat_confused

  I am having trouble understanding what is happening in the two lines with the 0xFF7F and the one below it. There is a link here that explains it to some degree. http://www.herongyang.com/java/Bit-String-Set-Bit-to-Byte-Array.html I don't know if 0xFF7FposBit) & oldByte) & 0x00FF are supposed to be 3 values 'AND'ed together or how this is supposed to be read. If anyone can clarify what is happening here a little better, I would greatly appreciate it. private static void setBit(byte[] data, final int pos, final int val) { int posByte = pos/8; int posBit = pos%8; byte oldByte = data[posByte]; oldByte = (byte) (((0xFF7F>>posBit) & oldByte) & 0x00FF); byte newByte = (byte) ((val<<(8-(posBit+1))) | oldByte); data[posByte] = newByte; } passed into this method as parameters from a selectBits method was setBit(out,i,val); out = is byte[] out = new byte[numOfBytes]; (numOfBytes can be 7 in this situation) i = which is number [57], the original number from the PC1 int array holding the 56-integers. val = which is the bit taken from the byte array from the getBit() method.

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• Pointers, am I doing them correctly? Objective-c/cocoa

  - by Chris

  I have this in my @interface struct track currentTrack; struct track previousTrack; int anInt; Since these are not objects, I do not have to have them like int* anInt right? And if setting non-object values like ints, boolean, etc, I do not have to release the old value right (assuming non-GC environment)? The struct contains objects: typedef struct track { NSString* theId; NSString* title; } *track; Am I doing that correctly? Lastly, I access the struct like this: [currentTrack.title ...]; currentTrack.theId = @"asdf"; //LINE 1 I'm also manually managing the memory (from a setter) for the struct like this: [currentTrack.title autorelease]; currentTrack.title = [newTitle retain]; If I'm understanding the garbage collection correctly, I should be able to ditch that and just set it like LINE 1 (above)? Also with garbage collection, I don't need a dealloc method right? If I use garbage collection does this mean it only runs on OS 10.5+? And any other thing I should know before I switch to garbage collected code? Sorry there are so many questions. Very new to objective-c and desktop programming. Thanks

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• SQLDeveloper using over 100MB of PGA+UGA

  - by Leigh Riffel

  Perhaps this is normal, but in my Oracle 11g database I am seeing programmers using Oracle's SQL Developer regularly consume more than 100MB of combined UGA and PGA memory. I'd like to know if this is normal and what can be done about it. Our database is on the 32 bit version of Windows 2008, so memory limitations are becoming an increasing concern. I am using the following query to show the memory usage: SELECT e.SID, e.username, e.status, b.PGA_MEMORY FROM v$session e LEFT JOIN (select y.SID, y.value pga, TO_CHAR(ROUND(y.value/1024/1024),99999999) || ' MB' PGA_MEMORY from v$sesstat y, v$statname z where y.STATISTIC# = z.STATISTIC# and NAME = 'session pga memory') b ON e.sid=b.sid WHERE (PGA)/1024/1024 > 20 ORDER BY 4 DESC; It seems that the resource usage goes up any time a table is opened in SQLDeveloper, but even when it is closed the memory does not go away. The problem is worse if the table is sorted while it was open as that seems to use even more memory. I understand how this would use memory while it is sorting, and perhaps even while it is still open, but to use memory after it is closed seems wrong to me. Can anyone confirm this? Update: I discovered that my numbers were off due to not understanding that the UGA is stored in the PGA under dedicated server mode. This makes the numbers lower than they were, but the problem still remains that SQL Developer seems to use excessive PGA.

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• How do you verify that 2 copies of a VB 6 executable came from the same code base?

  - by Tim Visher

  I have a program under version control that has gone through multiple releases. A situation came up today where someone had somehow managed to point to an old copy of the program and thus was encountering bugs that have since been fixed. I'd like to go back and just delete all the old copies of the program (keeping them around is a company policy that dates from before version control was common and should no longer be necessary) but I need a way of verifying that I can generate the exact same executable that is better than saying "The old one came out of this commit so this one should be the same." My initial thought was to simply MD5 hash the executable, store the hash file in source control, and be done with it but I've come up against a problem which I can't even parse. It seems that every time the executable is generated (method: Open Project. File Make X.exe) it hashes differently. I've noticed that Visual Basic messes with files every time the project is opened in seemingly random ways but I didn't think that would make it into the executable, nor do I have any evidence that that is indeed what's happening. To try to guard against that I tried generating the executable multiple times within the same IDE session and checking the hashes but they continued to be different every time. So that's: Generate Executable Generate MD5 Checksum: md5sum X.exe > X.md5 Verify MD5 for current executable: md5sum -c X.md5 Generate New Executable Verify MD5 for new executable: md5sum -c X.md5 Fail verification because computed checksum doesn't match. I'm not understanding something about either MD5 or the way VB 6 is generating the executable but I'm also not married to the idea of using MD5. If there is a better way to verify that two executables are indeed the same then I'm all ears. Thanks in advance for your help!

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• NSTimer as a timeout mechanism

  - by alexantd

  I'm pretty sure this is really simple, and I'm just missing something obvious. I have an app that needs to download data from a web service for display in a UITableView, and I want to display a UIAlertView if the operation takes more than X seconds to complete. So this is what I've got (simplified for brevity): MyViewController.h @interface MyViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> { NSTimer *timer; } @property (nonatomic, retain) NSTimer *timer; MyViewController.m @implementation MyViewController @synthesize timer; - (void)viewDidLoad { timer = [NSTimer scheduledTimerWithTimeInterval:20 target:self selector:@selector(initializationTimedOut:) userInfo:nil repeats:NO]; [self doSomethingThatTakesALongTime]; [timer invalidate]; } - (void)doSomethingThatTakesALongTime { sleep(30); // for testing only // web service calls etc. go here } - (void)initializationTimedOut:(NSTimer *)theTimer { // show the alert view } My problem is that I'm expecting the [self doSomethingThatTakesALongTime] call to block while the timer keeps counting, and I'm thinking that if it finishes before the timer is done counting down, it will return control of the thread to viewDidLoad where [timer invalidate] will proceed to cancel the timer. Obviously my understanding of how timers/threads work is flawed here because the way the code is written, the timer never goes off. However, if I remove the [timer invalidate], it does.

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• Why is JavaMail Transport.send() a static method?

  - by skiphoppy

  I'm revising code I did not write that uses JavaMail, and having a little trouble understanding why the JavaMail API is designed the way it is. I have the feeling that if I understood, I could be doing a better job. We call: transport = session.getTransport("smtp"); transport.connect(hostName, port, user, password); So why is Eclipse warning me that this: transport.send(message, message.getAllRecipients()); is a call to a static method? Why am I getting a Transport object and providing settings that are specific to it if I can't use that object to send the message? How does the Transport class even know what server and other settings to use to send the message? It's working fine, which is hard to believe. What if I had instantiated Transport objects for two different servers; how would it know which one to use? In the course of writing this question, I've discovered that I should really be calling: transport.sendMessage(message, message.getAllRecipients()); So what is the purpose of the static Transport.send() method? Is this just poor design, or is there a reason it is this way?

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• Doing coding in Linux through a virtual machine on Windows VS partitioning

  - by ihaveitnow

  I already have experience with setting up virtual machines, running them and other minor tasks. Im a gamer, so I wont get rid of windows (for now at least...) but I do want to be a great programmer and to be involved with the Open-Source community. Id like to know if its a good idea to do my programming in linux through a virtual machine, vs giving it a partitioned section of the HDD. Id like to know about performance pros and cons and functionality. All responses are appreciated, thanks in advance. The type of programming I intend to dive into : Android Dev, Web Dev, Desktop Dev...More Android and Web right now though. So im looking at C#,C,C++,Java,PHP,HTML,MySQL...Off the top of the dome. I do web designing as well, so dreamweaver is added as an "essential". But im sure I can do dreamweaver files and upload them to the server after programming in Linux...Right? And any info on IDE's in Linux for the above mentioned are appreciated, but i would prefer going the coding route and understanding the essence of whats happening "under the covers" Thanks to all for reading, I appreciate it. Hope this isnt confusing :S

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• Transaction to find an entity - locks all entities of that type?

  - by user246114

  Hi, Reading the docs for transactions: http://code.google.com/appengine/docs/java/datastore/transactions.html An example provided shows one way to make an instance of an object: try { tx.begin(); Key k = KeyFactory.createKey("SalesAccount", id); try { account = pm.getObjectById(Employee.class, k); } catch (JDOObjectNotFoundException e) { account = new SalesAccount(); account.setId(id); } ... When the above transaction gets executed, it will probably block all other write attempts on Account objects? I'm wondering because I'd like to have a user signup which checks for a username or email already in use: tx.begin(); "select from User where mUsername == str1 LIMIT 1"; if (count > 0) { throw new Exception("username already in use!"); } "select from User where mEmail == str1 LIMIT 1"; if (count > 0) { throw new Exception("email already in use!"); } pm.makePersistent(user(username, email)); // ok. tx.commit(); but the above would be even more time consuming I think, making an even worse bottleneck? Am I understanding what will happen correctly? Thanks

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• Why does instanceof seem to work in a static generic function sometimes?

  - by michael

  Greetings. This is my first post in this site. I thought that because of type erasure, one could not expect the following code to compile, and indeed, it did not compile on an earlier version of Eclipse. My understanding was that instanceof was a run-time operator and could not know about the generic type which would be, by run-time, compiled away: public static <E extends Comparable<? super E>> void SampleForQuestion(E e) { if ( !(e instanceof String) ) System.out.println("I am not a String"); else System.out.println("I am a String"); } However, I was surprised to see that one of your threads actually included some code like this in an answer, and my latest Eclipse (Galileo on Windows with JVM 1.6 rev 20) is perfectly happy with it -- and it works, too. (I did notice that someone said it worked on Eclipse but not in another IDE/JDK in that thread, but don't remember the specifics.) Can someone explain why it works, and more importantly, because I have to guide my students, whether it should be expected to work in the future. Thank you. (I hope the code formatting comes through correctly - it looks indented correctly from my perspective and there are no tabs.)

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• Returning c_str from a function

  - by user199421

  This is from a small library that I found online: const char* GetHandStateBrief(const PostFlopState* state) { static std::ostringstream out; ... rest of the function ... return out.str().c_str() Now in my code I am doing this: const char *d = GetHandStateBrief(&post); std::cout<< d << std::endl; Now, at first d contained garbage. I then realized that the c string I am getting from the function is destroyed when the function returns because std::ostringstream is allocated on the stack. So I added: return strdup( out.str().c_str()); And now I can get the text I need from the function. I have two questions: 1) Am I understanding this correctly? 2) I later noticed that the ostringstream was was allocated with static storage. Doesn't that mean that the object is supposed to stay in memory until the program terminates? and if so , then why can't I access the string?

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• Why my object sees variables which were not given to it in the constructor?

  - by Roman

  I have the following code. Which is "correct" and which I do not understand: private static void updateGUI(final int i, final JLabel label) { SwingUtilities.invokeLater( new Runnable() { public void run() { label.setText("You have " + i + " seconds."); } } ); } I create a new instance of the Runnable class and then in the run method of this instance I use variables label and i. It works, but I do not understand why it work. Why the considered object sees values of these variables. According to my understanding the code should look like that (and its wrong): private static void updateGUI(final int i, final JLabel label) { SwingUtilities.invokeLater(new Runnable(i,label) { public Runnable(int i, JLabel label) { this.i = i; this.label = label; } public void run() { label.setText("You have " + i + " seconds."); } }); } So, I would give the i and label variables to the constructor so the object can access them... By the way, in the updateGUI I use final before the i and label. I think I used final because compiler wanted that. But I do not understand why.

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• Google Charts - Adding Tooltip to Colorized Column Chart

  - by David K

  I created a column chart with google charts that has a different color assigned to each column using the following posting: Assign different color to each bar in a google chart But now I'm trying to figure out how to customize the tooltips for each column to also include the number of users in addition to the percent, so "raw_data[i][1]" I would like it to look like "70% (80 Users)" I understand that there is "data.addColumn({type:'number',role:'tooltip'});" but I'm having trouble understanding how to implement it for this use-case. function drawAccountsChart() { var data = new google.visualization.DataTable(); var raw_data = [ ['Parents', 80, 160], ['Students', 94, 128], ['Teachers', 78, 90], ['Admins', 68, 120], ['Staff', 97, 111] ]; data.addColumn('string', 'Columns'); for (var i = 0; i < raw_data.length; ++i) { data.addColumn('number', raw_data[i][0]); } data.addRows(1); for (var i = 0; i < raw_data.length; ++i) { data.setValue(0, i+1, raw_data[i][1]/raw_data[i][2]*100); } var options = { height:220, chartArea: { left:30, width: "70%", height: "70%" }, backgroundColor: { fill:"transparent" }, tooltop:{ textStyle: {fontSize: "12px",}}, vAxis: {minValue: 0} }; var formatter = new google.visualization.NumberFormat({ suffix: '%', fractionDigits: 1 }); formatter.format(data, 1); formatter.format(data, 2); formatter.format(data, 3); formatter.format(data, 4); formatter.format(data, 5); var chart = new google.visualization.ColumnChart(document.getElementById('emailAccountsChart')); chart.draw(data, options); }

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• Learning Basic Mathematics

  - by NeedsToKnow

  I'm going to just come out and say it. I'm 20 and can't do maths. Two years ago I passed the end-of-high-school mathematics exam (but not at school), and did pretty well. Since then, I haven't done a scrap of mathematics. I wondered just how bad I had gotten, so I was looking at some simple algebra problems. You know, the kind you learn halfway through highschool. 5(-3x - 2) - (x - 3) = -4(4x + 5) + 13 Couldn't do them. I've got half a year left until I start a Computer Science undergraduate degree. I love designing and creating programs, and I remember I loved mathematics back when I did it. Basically, I've had a pretty bad education, but I want to be knowledgable in these areas. I was thinking of buying some high school textbooks and reading them, but I'm not sure this is the right way to go. I need to start off at some basic level and work towards a greater understanding. My question is: What should I study, how should I study, and what books can you recommend? Thanks!

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• Macports and virtualenv site-packages Fallback

  - by Streeter

  I've installed django and python as this link suggested with macports. However, I'd like to use virtualenv to install more packages. My understanding is that if I do not pass in the --no-site-packages to virtualenv, I should get the currently installed packages in addition to whatever packages I install into the virtual environment. Is this correct? As an example, I've installed django through macports and then create a virtual environment, but I cannot import django from within that virtual environment: [streeter@mordecai]:~$ mkvirtualenv django-test New python executable in django-test/bin/python Installing setuptools............done. ... (django-test)[streeter@mordecai]:~$ pip install django-debug-toolbar Downloading/unpacking django-debug-toolbar Downloading django-debug-toolbar-0.8.4.tar.gz (80Kb): 80Kb downloaded Running setup.py egg_info for package django-debug-toolbar Installing collected packages: django-debug-toolbar Running setup.py install for django-debug-toolbar Successfully installed django-debug-toolbar Cleaning up... (django-test)[streeter@mordecai]:~$ python Python 2.6.1 (r261:67515, Jun 24 2010, 21:47:49) [GCC 4.2.1 (Apple Inc. build 5646)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> import django Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: No module named django >>> So I can install packages into the virtual environment, but it isn't picking up the global site-packages. Or am I not doing something correctly / missing something / misunderstanding how virtualenv works? I've got Mac OS 10.6 (Snow Leopard), have updated my macports packages and am using macports' python26 (via python_select python26).

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• Distinct Value Array for View Controller Index Using Core Data

  - by b.dot

  Hi, I'm trying to create an index representing the first letter value of each record in a Core Data store to be used in a table view controller. I'm using a snippet of the code from Apple's documentation. I would simply like to produce an array or dictionary of distinct values as the result. My store already has the character defined within each record object. Questions: 1) I'm having a problem understanding NSDictionaryResultType. Where does the resulting dictionary object get received so that I can assign it's keys to the view controller? The code seems to only return an array. 2) If I include the line containing NSDictionaryResultType, I get no returns. 3) I realize that I could do this in a loop, but I'm hoping this will work. Thanks! NSEntityDescription *entity = [NSEntityDescription entityForName:@"People" inManagedObjectContext:managedObjectContext]; NSFetchRequest *request = [[NSFetchRequest alloc] init]; [request setEntity:entity]; [request setResultType:NSDictionaryResultType]; // This line causes no no results. [request setReturnsDistinctResults:YES]; [request setPropertiesToFetch :[NSArray arrayWithObject:@"alphabetIndex"]]; NSError *error; NSArray *objects = [managedObjectContext executeFetchRequest:request error:&error];

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• Number of simple mutations to change one string to another?

  - by mstksg

  Hi; I'm sure you've all heard of the "Word game", where you try to change one word to another by changing one letter at a time, and only going through valid English words. I'm trying to implement an A* Algorithm to solve it (just to flesh out my understanding of A*) and one of the things that is needed is a minimum-distance heuristic. That is, the minimum number of one of these three mutations that can turn an arbitrary string a into another string b: 1) Change one letter for another 2) Add one letter at a spot before or after any letter 3) Remove any letter Examples aabca => abaca: aabca abca abaca = 2 abcdebf => bgabf: abcdebf bcdebf bcdbf bgdbf bgabf = 4 I've tried many algorithms out; I can't seem to find one that gives the actual answer every time. In fact, sometimes I'm not sure if even my human reasoning is finding the best answer. Does anyone know any algorithm for such purpose? Or maybe can help me find one? Thanks.

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• leak in fgets when assigning to buffer

  - by monkeyking

  I'm having problems understanding why following code leaks in one case, and not in the other case. The difference is while(NULL!=fgets(buffer,length,file))//doesnt leak while(NULL!=(buffer=fgets(buffer,length,file))//leaks I thought it would be the same. Full code below. #include <stdio.h> #include <stdlib.h> #define LENS 10000 void no_leak(const char* argv){ char *buffer = (char *) malloc(LENS); FILE *fp=fopen(argv,"r"); while(NULL!=fgets(buffer,LENS,fp)){ fprintf(stderr,"%s",buffer); } fclose(fp); fprintf(stderr,"%s\n",buffer); free(buffer); } void with_leak(const char* argv){ char *buffer = (char *) malloc(LENS); FILE *fp=fopen(argv,"r"); while(NULL!=(buffer=fgets(buffer,LENS,fp))){ fprintf(stderr,"%s",buffer); } fclose(fp); fprintf(stderr,"%s\n",buffer); free(buffer); }

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• about c# OBJECTS and the Possibilties it has.

  - by user527825

  As a novice programmer and i always wonder about c# capabilities.i know it is still early to judge that but all i want to know is can c# do complex stuffs or something outside windows OS. 1- I think c# is a proprietary language (i don't know if i said that right) meaning you can't do it outside visual studio or windows. 2-also you cant create your own controller(called object right?) like you are forced to use these available in toolbox and their properties and methods. 3-can c# be used with openGL API or DirectX API . 4-Finally it always bothers me when i think i start doing things in visual studio, i know it sounds arrogant to say but sometimes i feel that i don't like to be forced to use something even if its helpful, like i feel (do i have the right to feel?) that i want to do all things by myself? don't laugh i just feel that this will give me a better understanding. 5- is visual c# is like using MaxScript inside 3ds max in that c# is exclusive to do windows and forms and components that are windows related and maxscript is only for 3d editing and manipulation for various things in the software. If it is too difficult for a beginner i hope you don't answer the fourth question as i don't have enough motivation and i want to keep the little i have. thank you for your time. Note: 1-sorry for my English, i am self taught and never used the language with native speakers so expect so errors. 2-i have a lot of questions regarding many things, what is the daily ratio you think for asking (number of questions) that would not bother the admins of the site and the members here. thank you for your time.

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• SQL Server INSERT, Scope_Identity() and physical writing to disc

  - by TheBlueSky

  Hello everyone, I have a stored procedure that does, among other stuff, some inserts in different table inside a loop. See the example below for clearer understanding: INSERT INTO T1 VALUES ('something') SET @MyID = Scope_Identity() ... some stuff go here INSERT INTO T2 VALUES (@MyID, 'something else') ... The rest of the procedure These two tables (T1 and T2) have an IDENTITY(1, 1) column in each one of them, let's call them ID1 and ID2; however, after running the procedure in our production database (very busy database) and having more than 6250 records in each table, I have noticed one incident where ID1 does not match ID2! Although normally for each record inserted in T1, there is record inserted in T2 and the identity column in both is incremented consistently. The "wrong" records were something like that: ID1 Col1 ---- --------- 4709 data-4709 4710 data-4710 ID2 ID1 Col1 ---- ---- --------- 4709 4710 data-4709 4710 4709 data-4710 Note the "inverted", ID1 in the second table. Knowing not that much about SQL Server underneath operations, I have put the following "theory", maybe someone can correct me on this. What I think is that because the loop is faster than physically writing to the table, and/or maybe some other thing delayed the writing process, the records were buffered. When it comes the time to write them, they were wrote in no particular order. Is that even possible if no, how to explain the above mentioned scenario? If yes, then I have another question to rise. What if the first insert (from the code above) got delayed? Doesn't that mean I won't get the correct IDENTITY to insert into the second table? If the answer of this is also yes, what can I do to insure the insertion in the two tables will happen in sequence with the correct IDENTITY? I appreciate any comment and information that help me understand this. Thanks in advance.

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• Applying the Decorator Pattern to Forms

  - by devoured elysium

  I am trying to apply the Decorator Design Pattern to the following situation: I have 3 different kind of forms: Green, Yellow, Red. Now, each of those forms can have different set of attributes. They can have a minimize box disabled, a maximized box disabled and they can be always on top. I tried to model this the following way: Form <---------------------------------------FormDecorator /\ /\ |---------|-----------| |----------------------|-----------------| GreenForm YellowForm RedForm MinimizeButtonDisabled MaximizedButtonDisabled AlwaysOnTop Here is my GreenForm code: public class GreenForm : Form { public GreenForm() { this.BackColor = Color.GreenYellow; } public override sealed Color BackColor { get { return base.BackColor; } set { base.BackColor = value; } } } FormDecorator: public abstract class FormDecorator : Form { private Form _decoratorForm; protected FormDecorator(Form decoratorForm) { this._decoratorForm = decoratorForm; } } and finally NoMaximizeDecorator: public class NoMaximizeDecorator : FormDecorator { public NoMaximizeDecorator(Form decoratorForm) : base(decoratorForm) { this.MaximizeBox = false; } } So here is the running code: static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(CreateForm()); } static Form CreateForm() { Form form = new GreenForm(); form = new NoMaximizeDecorator(form); form = new NoMinimizeDecorator(form); return form; } The problem is that I get a form that isn't green and that still allows me to maximize it. It is only taking in consideration the NoMinimizeDecorator form. I do comprehend why this happens but I'm having trouble understanding how to make this work with this Pattern. I know probably there are better ways of achieving what I want. I made this example as an attempt to apply the Decorator Pattern to something. Maybe this wasn't the best pattern I could have used(if one, at all) to this kind of scenario. Is there any other pattern more suitable than the Decorator to accomplish this? Am I doing something wrong when trying to implement the Decorator Pattern? Thanks

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• JVM GC demote object to eden space?

  - by Kevin

  I'm guessing this isn't possible...but here goes. My understanding is that eden space is cheaper to collect than old gen space, especially when you start getting into very large heaps. Large heaps tend to come up with long running applications (server apps) and server apps a lot of the time want to use some kind of caches. Caches with some kind of eviction (LRU) tend to defeat some assumptions that GC makes (temporary objects die quickly). So cache evictions end up filling up old gen faster than you'd like and you end up with a more costly old gen collection. Now, it seems like this sort of thing could be avoided if java provided a way to mark a reference as about to die (delete keyword)? The difference between this and c++ is that the use is optional. And calling delete does not actually delete the object, but rather is a hint to the GC that it should demote the object back to Eden space (where it will be more easily collected). I'm guessing this feature doesn't exist, but, why not (is there a reason it's a bad idea)?

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• How do I create a simple Windows form to access a SQL Server database?

  - by NoCatharsis

  I believe this is a very novice question, and if I'm using the wrong forum to ask, please advise. I have a basic understanding of databasing with MS SQL Server, and programming with C++ and C#. I'm trying to teach myself more by setting up my own database with MS SQL Server Express 2008 R2 and accessing it via Windows forms created in C# Express 2010. At this point, I just want to keep it to free or Express dev tools (not necessarily Microsoft though). Anyway, I created a database using the instructions provided here and I set the data types appropriately for each column (no errors in setup at least). Now I'm designing the GUI in C# Express but I've kind of hit a wall as far as the database connection. Is there a simple way to access the database I created locally using C# Express? Can anyone suggest a guide that has all this spelled out already? I am a self-learner so I look forward to teaching myself how to use these applications, but any pointers to start me off in the right direction would be greatly appreciated.

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• Endianness and C API's: Specifically OpenSSL.

  - by Hassan Syed

  I have an algorithm that uses the following OpenSSL calls: HMAC_update() / HMAC_final() // ripe160 EVP_CipherUpdate() / EVP_CipherFinal() // cbc_blowfish These algorithm take a unsigned char * into the "plain text". My input data is comes from a C++ std::string::c_str() which originate from a protocol buffer object as a encoded UTF-8 string. UTF-8 strings are meant to be endian neutrial. However I'm a bit paranoid about how OpenSSL may perform operations on the data. My understanding is that encryption algorithms work on 8-bit blocks of data, and if a unsigned char * is used for pointer arithmetic when the operations are performed the algorithms should be endian neutral and I do not need to worry about anything. My uncertainty is compounded by the fact that I am working on a little-endian machine and have never done any real cross-architecture programming. My beliefs/reasoning are/is based on the following two properties std::string (not wstring) internally uses a 8-bit ptr and a the resulting c_str() ptr will itterate the same way regardless of the CPU architecture. Encryption algorithms are either by design, or by implementation, endian neutral. I know the best way to get a definitive answer is to use QEMU and do some cross-platform unit tests (which I plan to do). My question is a request for comments on my reasoning, and perhaps will assist other programmers when faced with similar problems.

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• How can I get a custom made set of checkboxes return values in the postback?

  - by AngryHacker

  I have the following in an aspx page: <td colspan="2"> <% DisplayParties(); %> </td> In the code behind for the aspx page, i have this (e.g. I build HTML for the checkboxes): public void DisplayParties() { var s = new StringBuilder(); s.Append("<input type=\"checkbox\" id=\"attorney\" value=\"12345\"/>"); s.Append("<input type=\"checkbox\" id=\"attorney\" value=\"67890\"/>"); s.Append("<input type=\"checkbox\" id=\"adjuster\" value=\"125\"/>"); Response.WriteLine(s.ToString()); } Not my proudest moment, but whatever. The problem is that when this page posts back via some event on the page, I never get these tags in the Request.Form collection. Is this simply how ASP.NET works (e.g. only server-side control post back) or am I missing something simple. My understanding was that a postback should bring back all the form variables.

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