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  • sqlite3 - stringWithUTF8String is leaking!

    - by Darko Hebrang
    I would appreciate if someone could help me solve my leaking problem. The leaks occur at: aImage, aCategory, aDescription, category and categories. I release them in dealloc, but obviously that is not sufficient: -(void) readListFromDatabase:(char *) sqlStatement { // Setup some globals databaseName = @"mydatabase.sql"; // Get the path to the documents directory and append the databaseName NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDir = [documentPaths objectAtIndex:0]; databasePath = [documentsDir stringByAppendingPathComponent:databaseName]; // Setup the database object sqlite3 *database; // Init the categories Array categories = [[NSMutableArray alloc] init]; // Open the database from the users filessytem if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) { // Setup the SQL Statement and compile it for faster access sqlite3_stmt *compiledStatement; if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) { // Loop through the results and add them to the feeds array while(sqlite3_step(compiledStatement) == SQLITE_ROW) { // Read the data from the result row aImage = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 0)]; aCategory = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)]; aDescription = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)]; // Create a new category object with the data from the database category=[[Category alloc] initWithName:aImage category_name:aCategory description_text:aDescription]; // Add the category object to the categories Array [categories addObject:category]; [category release]; } } // Release the compiled statement from memory sqlite3_finalize(compiledStatement); } sqlite3_close(database); } - (void)dealloc { [databaseName release]; [databasePath release]; [categories release]; [aImage release]; [aCategory release]; [aDescription release]; [category release]; [super dealloc]; }

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  • Looking for advice on importing large dataset in sqlite and Cocoa/Objective-C

    - by jluckyiv
    I have a fairly large hierarchical dataset I'm importing. The total size of the database after import is about 270MB in sqlite. My current method works, but I know I'm hogging memory as I do it. For instance, if I run with Zombies, my system freezes up (although it will execute just fine if I don't use that Instrument). I was hoping for some algorithm advice. I have three hierarchical tables comprising about 400,000 records. The highest level has about 30 records, the next has about 20,000, the last has the balance. Right now, I'm using nested for loops to import. I know I'm creating an unreasonably large object graph, but I'm also looking to serialize to JSON or XML because I want to break up the records into downloadable chunks for the end user to import a la carte. I have the code written to do the serialization, but I'm wondering if I can serialize the object graph if I only have pieces in memory. Here's pseudocode showing the basic process for sqlite import. I left out the unnecessary detail. [database open]; [database beginTransaction]; NSArray *firstLevels = [[FirstLevel fetchFromURL:url retain]; for (FirstLevel *firstLevel in firstLevels) { [firstLevel save]; int id1 = [firstLevel primaryKey]; NSArray *secondLevels = [[SecondLevel fetchFromURL:url] retain]; for (SecondLevel *secondLevel in secondLevels) { [secondLevel saveWithForeignKey:id1]; int id2 = [secondLevel primaryKey]; NSArray *thirdLevels = [[ThirdLevel fetchFromURL:url] retain]; for (ThirdLevel *thirdLevel in thirdLevels) { [thirdLevel saveWithForeignKey:id2]; } [database commit]; [database beginTransaction]; [thirdLevels release]; } [secondLevels release]; } [database commit]; [database release]; [firstLevels release];

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  • django url user id versus userprofile id problem

    - by dana
    hello there, i have a mini comunity where each user can search and find another user profile. Userprofile is a class model, indexed differently compared to user model class (user id is not equal to userprofile id) But i cannot see a user profile by typing in the url the corresponding id. I only see the profile of the currently logged in user. Why is that? I'd also want to have in my url the username (a primary key of the user table also) and NOT the id (a number). The guilty part of the code is: what can i replace that request.user with so that it wil actually display the user i searched for, and not the currently logged in? def profile_view(request, id): u = UserProfile.objects.get(pk=id) cv = UserProfile.objects.filter(created_by = request.user) blog = New.objects.filter(created_by = request.user) return render_to_response('profile/publicProfile.html', { 'u':u, 'cv':cv, 'blog':blog, }, context_instance=RequestContext(request)) in urls (of the accounts app): url(r'^profile_view/(?P<id>\d+)/$', profile_view, name='profile_view'), and in template: <h3>Recent Entries:</h3> {% load pagination_tags %} {% autopaginate list 10 %} {% paginate %} {% for object in list %} <li>{{ object.post }} <br /> Voted: {{ vote.count }} times.<br /> {% for reply in object.reply_set.all %} {{ reply.reply }} <br /> {% endfor %} <a href=''> {{ object.created_by }}</a> <br /> {{object.date}} <br /> <a href = "/vote/save_vote/{{object.id}}/">Vote this</a> <a href="/replies/save_reply/{{object.id}}/">Comment</a> </li> {% endfor %} thanks in advance!

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  • Dependecy Injection with Massive ORM: dynamic trouble

    - by Sergi Papaseit
    I've started working on an MVC 3 project that needs data from an enormous existing database. My first idea was to go ahead and use EF 4.1 and create a bunch of POCO's to represent the tables I need, but I'm starting to think the mapping will get overly complicated as I only need some of the columns in some of the tables. (thanks to Steven for the clarification in the comments. So I thought I'd give Massive ORM a try. I normally use a Unit of Work implementation so I can keep everything nicely decoupled and can use Dependency Injection. This is part of what I have for Massive: public interface ISession { DynamicModel CreateTable<T>() where T : DynamicModel, new(); dynamic Single<T>(string where, params object[] args) where T : DynamicModel, new(); dynamic Single<T>(object key, string columns = "*") where T : DynamicModel, new(); // Some more methods supported by Massive here } And here's my implementation of the above interface: public class MassiveSession : ISession { public DynamicModel CreateTable<T>() where T : DynamicModel, new() { return new T(); } public dynamic Single<T>(string where, params object[] args) where T: DynamicModel, new() { var table = CreateTable<T>(); return table.Single(where, args); } public dynamic Single<T>(object key, string columns = "*") where T: DynamicModel, new() { var table = CreateTable<T>(); return table.Single(key, columns); } } The problem comes with the First(), Last() and FindBy() methods. Massive is based around a dynamic object called DynamicModel and doesn't define any of the above method; it handles them through a TryInvokeMethod() implementation overriden from DynamicObject instead: public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { } I'm at a loss on how to "interface" those methods in my ISession. How could my ISession provide support for First(), Last() and FindBy()? Put it another way, how can I use all of Massive's capabilities and still be able to decouple my classes from data access?

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  • Ruby script/console and Ruby script/server using two different DBs?

    - by aronchick
    Has anyone seen where script/console and script/server load two different databases (though both report using the same)? Here's the first output $ script/server => Booting WEBrick => Rails 2.3.5 application starting on http://0.0.0.0:3000 => Call with -d to detach => Ctrl-C to shutdown server [2010-03-21 15:54:05] INFO WEBrick 1.3.1 [2010-03-21 15:54:05] INFO ruby 1.8.7 (2010-01-10) [i386-mingw32] [2010-03-21 15:54:05] INFO WEBrick::HTTPServer#start: pid=7148 port=3000 No errors. I then run my standard code for entering a form - no problems. Checking the Dev Database (.yml at bottom): mysql> select * from books; [...] | 712 | Book | Book Name | 2010-03-21 22:29:22 | 2010-03-21 22:29:22 | [...] 712 rows in set (0.00 sec) The code CLEARLY saved it seconds ago And now here's the output of script/console: $ script/console Loading development environment (Rails 2.3.5) >> Books.all => [] Nothing. Further, upon further inspection, it's using the production database, but I can't figure out why. Any thoughts here? All consoles have been closed and reopened. UPDATE: Requested .yml file (can't see how it'd be helpful (user name and password are all the same for each)) - development: adapter: mysql database: BooksDBdev username: <user name> password: <long string> timeout: 5000 # Warning: The database defined as "test" will be erased and # re-generated from your development database when you run "rake". # Do not set this db to the same as development or production. test: adapter: mysql database: BooksDBtest username: <user name> password: <long string> timeout: 5000 production: adapter: mysql database: BooksDB username: <user name> password: <long string> timeout: 5000

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  • How to update the user profile through tokenid when a particular user logs in using his username and password

    - by Rani
    i have an application in which when the user enters his username and password in the login form , his username and password are submitted to the server database for validation and if he is a valid user a tokenid is generated for him through JSON response and he is allowed to log in.this is the JSON response that i get in the console when a valid user log in through the log in form : {"TokenID":"kaenn43otO","isError":false,"ErrorMessage":"","Result":[{"UserId":"164","FirstName":"Indu","LastName":"nair","Email":"[email protected]","ProfileImage":null,"ThumbnailImage":null,"DeviceInfoId":"22"}],"ErrorCode":900} 2011-06-24 11:56:57.639 Journey[5526:207] this is token id:kaenn43otO so when the same user wants to update his profile by clicking on the update tab using the tokenid So that if he want he can his firstname,lastname,password,email.etc.i i have done the following code to update the user profile using tokenid but it does not work.i get tokenid when the user log in and this tokenid i have to pass to other class: this is my code to update user profile: -(void)sendRequest { //this is the class in which i get the tokenid and i am passing it to this class apicontroller *apitest = [[apicontroller alloc]init]; NSString *tokentest = apitest.tokenapi; NSString *post = [NSString stringWithFormat:@"Token=%@&firstname=%@&lastname=%@&Username=%@&Password=%@&Email=%@",tokentest,txtfirstName.text,txtlast.text,txtUserName.text,txtPassword.text,txtEmail.text]; NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]; NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]]; NSLog(@"%@",postLength); NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease]; [request setURL:[NSURL URLWithString:@"http://192.168.0.1:96/JourneyMapperAPI?RequestType=Register&Command=SET"]]; [request setHTTPMethod:@"POST"]; [request setValue:postLength forHTTPHeaderField:@"Content-Length"]; [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"]; [request setHTTPBody:postData]; NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; if (theConnection) { webData = [[NSMutableData data] retain]; NSLog(@"%@",webData); [theConnection start]; } else { } } -(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response { [webData setLength: 0]; } -(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { [webData appendData:data]; } -(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { [connection release]; [webData release]; } -(void)connectionDidFinishLoading:(NSURLConnection *)connection { NSString *loginStatus = [[NSString alloc] initWithBytes: [webData mutableBytes] length:[webData length] encoding:NSUTF8StringEncoding]; NSLog(@"%@",loginStatus); [loginStatus release]; [connection release]; [webData release]; } -(IBAction)click:(id)sender { [self sendRequest]; } this is my apicontroller.m file in which i am creating login form so that user login and in this page tokenid is generated -(void)sendRequest { UIDevice *device = [UIDevice currentDevice]; NSString *udid = [device uniqueIdentifier]; //NSString *sysname = [device systemName]; NSString *sysver = [device systemVersion]; NSString *model = [device model]; NSLog(@"idis:%@",[device uniqueIdentifier]); NSLog(@"system nameis :%@",[device systemName]); NSLog(@"System version is:%@",[device systemVersion]); NSLog(@"System model is:%@",[device model]); NSLog(@"device orientation is:%d",[device orientation]); NSString *post = [NSString stringWithFormat:@"Loginkey=%@&Password=%@&DeviceCode=%@&Firmware=%@&IMEI=%@",txtUserName.text,txtPassword.text,model,sysver,udid]; NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]; NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]]; NSLog(@"%@",postLength); NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease]; [request setURL:[NSURL URLWithString:@"http://192.168.0.1:96/JourneyMapperAPI?RequestType=Login"]]; [request setHTTPMethod:@"POST"]; [request setValue:postLength forHTTPHeaderField:@"Content-Length"]; [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"]; [request setHTTPBody:postData]; NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; if (theConnection) { webData = [[NSMutableData data] retain]; NSLog(@"%@",webData); } else { } } //to select username and password from database. -(void)check { //app.journeyList = [[NSMutableArray alloc]init]; [self createEditableCopyOfDatabaseIfNeeded]; NSString *filePath = [self getWritableDBPath]; sqlite3 *database; if(sqlite3_open([filePath UTF8String], &database) == SQLITE_OK) { const char *sqlStatement = "SELECT Username,Password FROM UserInformation where Username=? and Password=?"; sqlite3_stmt *compiledStatement; if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) { sqlite3_bind_text(compiledStatement, 1, [txtUserName.text UTF8String], -1, SQLITE_TRANSIENT); sqlite3_bind_text(compiledStatement, 2, [txtPassword.text UTF8String], -1, SQLITE_TRANSIENT); //NSString *loginname= [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)]; // NSString *loginPassword = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)]; } if(sqlite3_step(compiledStatement) != SQLITE_ROW ) { NSLog( @"Save Error: %s", sqlite3_errmsg(database) ); UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"UIAlertView" message:@"User is not valid" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alert show]; [alert release]; alert = nil; } else { isUserValid = YES; if (isUserValid) { UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"UIAlertView" message:@"Valid User" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alert show]; [alert release]; } } sqlite3_finalize(compiledStatement); } sqlite3_close(database); } -(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response { [webData setLength: 0]; } -(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { [webData appendData:data]; } -(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { [connection release]; [webData release]; } -(void)connectionDidFinishLoading:(NSURLConnection *)connection { NSString *loginStatus = [[NSString alloc] initWithBytes: [webData mutableBytes] length:[webData length] encoding:NSUTF8StringEncoding]; NSLog(@"%@",loginStatus); //this is to perfrom insert opertion on the userinformation table NSString *json_string = [[NSString alloc] initWithData:webData encoding:NSUTF8StringEncoding]; NSDictionary *result = [json_string JSONValue]; //here i am storing the tokenid tokenapi = [result objectForKey:@"TokenID"]; NSLog(@"this is token id:%@",tokenapi); // BOOL errortest = [[result objectForKey:@"isError"] boolValue]; if(errortest == FALSE) { values = [result objectForKey:@"Result"]; NSLog(@"Valid User"); } else { NSLog(@"Invalid User"); } NSMutableArray *results = [[NSMutableArray alloc] init]; for (int index = 0; index<[values count]; index++) { NSMutableDictionary * value = [values objectAtIndex:index]; Result * result = [[Result alloc] init]; //through this i get the userid result.UserID = [value objectForKey:@"UserId"]; result.FirstName = [value objectForKey:@"FirstName"]; result.Username =[value objectForKey:@"Username"]; result.Email =[value objectForKey:@"Email"]; result.ProfileImage =[value objectForKey:@"ProfileImage"]; result.ThumbnailImage =[value objectForKey:@"ThumbnailImage"]; result.DeviceInfoId =[value objectForKey:@"DeviceInfoId"]; NSLog(@"%@",result.UserID); [results addObject:result]; [result release]; } for (int index = 0; index<[results count]; index++) { Result * result = [results objectAtIndex:index]; //save the object variables to database here [self createEditableCopyOfDatabaseIfNeeded]; NSString *filePath = [self getWritableDBPath]; sqlite3 *database; if(sqlite3_open([filePath UTF8String], &database) == SQLITE_OK) { const char *sqlStatement = "insert into UserInformation(UserID,DeviceId,Username,Password,FirstName,Email) VALUES (?,?,?,?,?,?)"; sqlite3_stmt *compiledStatement; if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) { //sqlite3_bind_text( compiledStatement, 1, [journeyid UTF8String],-1,SQLITE_TRANSIENT); sqlite3_bind_text( compiledStatement, 1, [result.UserID UTF8String],-1,SQLITE_TRANSIENT); sqlite3_bind_text(compiledStatement, 2, [result.DeviceInfoId UTF8String],-1,SQLITE_TRANSIENT); sqlite3_bind_text(compiledStatement, 3, [txtUserName.text UTF8String],-1,SQLITE_TRANSIENT); sqlite3_bind_text(compiledStatement, 4, [txtPassword.text UTF8String],-1,SQLITE_TRANSIENT); sqlite3_bind_text (compiledStatement, 5, [result.FirstName UTF8String],-1,SQLITE_TRANSIENT); sqlite3_bind_text (compiledStatement, 6, [result.Email UTF8String],-1,SQLITE_TRANSIENT); } if(sqlite3_step(compiledStatement) != SQLITE_DONE ) { NSLog( @"Save Error: %s", sqlite3_errmsg(database) ); } else { UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"UIAlertView" message:@"Record added" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alert show]; [alert release]; alert = nil; } sqlite3_finalize(compiledStatement); } sqlite3_close(database); } [loginStatus release]; [connection release]; [webData release]; } -(IBAction)click:(id)sender { [self sendRequest]; //this is to select username and password from database. [self check]; } for a particular user who logs in only his profile must be update by using tokenid and userid.Please help me in solving this problem.Thanks

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  • DotNetOpenAuth occasionally throws a NotImplementedException

    - by Chris Moschini
    I have DotNetOpenAuth running on a background thread making calls to Google authorized with OAuth on a regular basis. About once a day, which is about one in 10,000 calls, I get the following Exception: An unhandled exception occurred and the process was terminated. Application ID: DefaultDomain Process ID: 3316 Exception: System.NotImplementedException Message: The method or operation is not implemented. StackTrace: at DotNetOpenAuth.Messaging.ProtocolException.GetObjectData(SerializationInfo info, StreamingContext context) in c:\Users\andarno\git\dotnetopenid\src\DotNetOpenAuth\Messaging\ProtocolException.cs:line 90 at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter, SerializationBinder binder) at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.Serialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter, SerializationBinder binder) at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object graph, Header[] inHeaders, __BinaryWriter serWriter, Boolean fCheck) at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph, Header[] headers, Boolean fCheck) at System.Runtime.Remoting.Channels.CrossAppDomainSerializer.SerializeObject(Object obj, MemoryStream stm) at System.AppDomain.Serialize(Object o) at System.AppDomain.MarshalObject(Object o) If it was thrown and caught once a day I'd be fine, but this is a big one - I'm getting this in the Application Error log on the server, and it's crashing the process entirely - the site goes down and restarts. Has anyone else run into this? Something I'm clearly doing wrong?

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  • How to provide js-ctypes in a spidermonkey embedding?

    - by Triston J. Taylor
    Summary I have looked over the code the SpiderMonkey 'shell' application uses to create the ctypes JavaScript object, but I'm a less-than novice C programmer. Due to the varying levels of insanity emitted by modern build systems, I can't seem to track down the code or command that actually links a program with the desired functionality. method.madness This js-ctypes implementation by The Mozilla Devs is an awesome addition. Since its conception, scripting has been primarily used to exert control over more rigorous and robust applications. The advent of js-ctypes to the SpiderMonkey project, enables JavaScript to stand up and be counted as a full fledged object oriented rapid application development language flying high above 'the bar' set by various venerable application development languages such as Microsoft's VB6. Shall we begin? I built SpiderMonkey with this config: ./configure --enable-ctypes --with-system-nspr followed by successful execution of: make && make install The js shell works fine and a global ctypes javascript object was verified operational in that shell. Working with code taken from the first source listing at How to embed the JavaScript Engine -MDN, I made an attempt to instantiate the JavaScript ctypes object by inserting the following code at line 66: /* Populate the global object with the ctypes object. */ if (!JS_InitCTypesClass(cx, global)) return NULL; /* I compiled with: g++ $(./js-config --cflags --libs) hello.cpp -o hello It compiles with a few warnings: hello.cpp: In function ‘int main(int, const char**)’: hello.cpp:69:16: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null] hello.cpp:80:20: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] hello.cpp:89:17: warning: NULL used in arithmetic [-Wpointer-arith] But when you run the application: ./hello: symbol lookup error: ./hello: undefined symbol: JS_InitCTypesClass Moreover JS_InitCTypesClass is declared extern in 'dist/include/jsapi.h', but the function resides in 'ctypes/CTypes.cpp' which includes its own header 'CTypes.h' and is compiled at some point by some command during 'make' to yeild './CTypes.o'. As I stated earlier, I am less than a novice with the C code, and I really have no idea what to do here. Please give or give direction to a generic example of making the js-ctypes object functional in an embedding.

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  • Can PHP dissect its own syntax?

    - by Nathan Long
    Can PHP dissect its own syntax? For example, I'd like to write a function that takes in an input like $object->attribute and says to itself: OK, he's giving me $foo->bar, which means he must think that $foo is an object that has a property called bar. Before I try accessing bar and potentially get a 'Trying to get property of non-object' error, let me check whether $foo is even an object. The end goal is to echo a value if it is set, and fail silently if not. I want to avoid repetition like this: <input value="<? if(is_object($foo) && is_set($foo->bar)){ echo $foo->bar; }?> "/> ...and to avoid writing a function that does the above, but has to have the object and attribute passed in separately, like this: <input value="<? echoAttribute($foo,'bar') ?>" /> ...but to instead write something which: preserves the object-attribute syntax is flexible: can also handle array keys or regular variables Like this: <input value="<? echoIfSet($foo->bar); ?> /> <input value="<? echoIfSet($baz['buzz']); ?> /> <input value="<? echoIfSet($moo); ?> /> But this all depends on PHP being able to tell me "what kind of thing am I asking for when I say $object->attribute or $array[$key]", so that my function can handle each according to its own type. Is this possible?

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  • Javascript: prototypeal inheritance and the prototype property

    - by JanD
    Hi, I have a simple code fragment in JS working with prototype inheritance. function object(o) { function F() {} F.prototype = o; return new F(); } //the following code block has a alternate version var mammal = { color: "brown", getColor: function() { return this.color; } } var myCat = object(mammal); myCat.meow = function(){return "meow";} that worked fine but adding this: mammal.prototype.kindOf = "predator"; does not. ("mammal.prototype is undefined") Since I guessed that object maybe have no prototype I rewrote it, replacing the var mammal={... block with: function mammal() { this.color = "brown"; this.getColor = function() { return this.color; } } which gave me a bunch of other errors: "Function.prototype.toString called on incompatible object" and if I try to call _myCat.getColor() "myCat.getColor is not a function" Now I am totally confused. After reading Crockford, and Flanagan I did not get the solution for the errors. So it would be great if somebody knows... - why is the prototype undefined in the first example (which is foremost concern; I thought the prototype of explicitly set in the object() function) - why get I these strange errors trying to use the mammal function as prototype object in the object() function?

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  • mysqldb interfaceError

    - by Johanna
    I have a very weird probleme with mysqldb (mysql module for python). I have a file with queries for inserting records in tables. If I call the functions from the file, it works just fine. But when I try to call one of the functions from another file it throws me a _mysql_exception.InterfaceError: (0, '') I really don't get what I'm doing wrong here.. I call the function from buildDB.py : import create create.newFormat("HD", 0,0,0) The function newFormat(..) is in create.py (imported) : from Database import Database db = Database() def newFormat(name, width=0, height=0, fps=0): format_query = "INSERT INTO Format (form_name, form_width, form_height, form_fps) VALUES ('"+name+"',"+str(width)+","+str(height)+","+str(fps)+");" db.execute(format_query) And the class Databse is the following : import MySQLdb from MySQLdb.constants import FIELD_TYPE class Database(): def __init__(self): server = "localhost" login = "seq" password = "seqmanager" database = "Sequence" my_conv = { FIELD_TYPE.LONG: int } self.conn = MySQLdb.connection(host=server, user=login, passwd=password, db=database, conv=my_conv) # self.cursor = self.conn.cursor() def close(self): self.conn.close() def execute(self, query): self.conn.query(query) (I put only relevant code) Traceback : Z:\sequenceManager\mysql>python buildDB.py D:\ProgramFiles\Python26\lib\site-packages\MySQLdb\__init__.py:34: DeprecationWa rning: the sets module is deprecated from sets import ImmutableSet INSERT INTO Format (form_name, form_width, form_height, form_fps) VALUES ('HD',0 ,0,0); Traceback (most recent call last): File "buildDB.py", line 182, in <module> create.newFormat("HD") File "Z:\sequenceManager\mysql\create.py", line 52, in newFormat db.execute(format_query) File "Z:\sequenceManager\mysql\Database.py", line 19, in execute self.conn.query(query) _mysql_exceptions.InterfaceError: (0, '') The warning has never been a problem before so I don't think it's related.

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  • Is this a safe/valid hash method implementation?

    - by Sean
    I have a set of classes to represent some objects loaded from a database. There are a couple variations of these objects, so I have a common base class and two subclasses to represent the differences. One of the key fields they have in common is an id field. Unfortunately, the id of an object is not unique across all variations, but within a single variation. What I mean is, a single object of type A could have an id between, say, 0 and 1,000,000. An object of type B could have an id between, 25,000 and 1,025,000. This means there's some overlap of id numbers. The objects are just variations of the same kind of thing, though, so I want to think of them as such in my code. (They were assigned ids from different sets for legacy reasons.) So I have classes like this: @class BaseClass @class TypeAClass : BaseClass @class TypeBClass : BaseClass BaseClass has a method (NSNumber *)objectId. However instances of TypeA and TypeB could have overlapping ids as discussed above, so when it comes to equality and putting these into sets, I cannot just use the id alone to check it. The unique key of these instances is, essentially, (class + objectId). So I figured that I could do this by making the following hash function on the BaseClass: -(NSUInteger)hash { return (NSUInteger)[self class] ^ [self.objectId hash]; } I also implemented isEqual like so: - (BOOL)isEqual:(id)object { return (self == object) || ([object class] == [self class] && [self.objectId isEqual:[object objectId]]); } This seems to be working, but I guess I'm just asking here to make sure I'm not overlooking something - especially with the generation of the hash by using the class pointer in that way. Is this safe or is there a better way to do this?

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  • C# Late Binding for Parameterized Property

    - by optim
    I'm trying to use late binding to connect to a COM automation API provided by a program called Amibroker, using a C# WinForms project. So far I've been able to connect to everything in the API except one item, which I believe to be a "parameterized property" based on extensive Googling. Here's what the API specification looks like according to the docs (Full version here: http://www.amibroker.com/guide/objects.html): Property Filter(ByVal nType As Integer, ByVal pszCategory As String) As Long [r/w] A javascript snippet to update the value looks like this: AB = new ActiveXObject("Broker.Application"); AA = AB.Analysis; AA.Filter( 0, "market" ) = 0; Using the following C# late-binding code, I can get the value of the property, but I can't for the life of me figure out how to set the value: object[] parameter = new object[2]; parameter[0] = Number; parameter[1] = Type; object filters = _analysis.GetType().InvokeMember("Filter", BindingFlags.GetProperty, null, _analysis, parameter); So far I have tried: using BindingFlags.SetProperty, BindingFlags.SetField casting the returned object to a PropertyInfo object and trying to update the value using it adding extra object containing the value to the parameters object various other things as last-ditch efforts From what I can see, this should be straight-forward, but I'm finding the late binding in C# to be cumbersome at best. The property looks like a method call to me, which is what is throwing me off. How does one assign a value to a method, and what would the prototype for late-binding C# code look like for it? Hopefully that explains it well enough, but feel free to ask if I've left anything unclear. Thanks in advance for any help! Daniel

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  • Spring: Bean fails to read off values from external Properties file when using @Value annotation

    - by daydreamer
    XML Configuration <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd"> <util:properties id="mongoProperties" location="file:///storage/local.properties" /> <bean id="mongoService" class="com.business.persist.MongoService"></bean> </beans> and MongoService looks like @Service public class MongoService { @Value("#{mongoProperties[host]}") private String host; @Value("#{mongoProperties[port]}") private int port; @Value("#{mongoProperties[database]}") private String database; private Mongo mongo; private static final Logger LOGGER = LoggerFactory.getLogger(MongoService.class); public MongoService() throws UnknownHostException { LOGGER.info("host=" + host + ", port=" + port + ", database=" + database); mongo = new Mongo(host, port); } public void putDocument(@Nonnull final DBObject document) { LOGGER.info("inserting document - " + document.toString()); mongo.getDB(database).getCollection(getCollectionName(document)).insert(document, WriteConcern.SAFE); } I write my MongoServiceTest as public class MongoServiceTest { @Autowired private MongoService mongoService; public MongoServiceTest() throws UnknownHostException { mongoRule = new MongoRule(); } @Test public void testMongoService() { final DBObject document = DBContract.getUniqueQuery("001"); document.put(DBContract.RVARIABLES, "values"); document.put(DBContract.PVARIABLES, "values"); mongoService.putDocument(document); } and I see failures in tests as 12:37:25.224 [main] INFO c.s.business.persist.MongoService - host=null, port=0, database=null java.lang.NullPointerException at com.business.persist.MongoServiceTest.testMongoService(MongoServiceTest.java:40) Which means bean was not able to read the values from local.properties local.properties ### === MongoDB interaction === ### host="127.0.0.1" port=27017 database=contract How do I fix this? update It doesn't seem to read off the values even after creating setters/getters for the fields. I am really clueless now. How can I even debug this issue? Thanks much!

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  • Question about cloning in Java

    - by devoured elysium
    In Effective Java, the author states that: If a class implements Cloneable, Object's clone method returns a field-by-field copy of the object; otherwise it throws CloneNotSupportedException. What I'd like to know is what he means with field-by-field copy. Does it mean that if the class has X bytes in memory, it will just copy that piece of memory? If yes, then can I assume all value types of the original class will be copied to the new object? class Point { private int x; private int y; @Override public Point clone() { return (Point)super.clone(); } } If what Object.clone() does is a field by field copy of the Point class, I'd say that I wouldn't need to explicitly copy fields x and y, being that the code shown above will be more than enough to make a clone of the Point class. That is, the following bit of code is redundant: @Override public Point clone() { Point newObj = (Point)super.clone(); newObj.x = this.x; //redundant newObj.y = this.y; //redundant } Am I right? I know references of the cloned object will point automatically to where the original object's references pointed to, I'm just not sure what happens specifically with value types. If anyone could state clearly what Object.clone()'s algorithm specification is (in easy language) that'd be great. Thanks

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  • i dont understand error while connecting php and mysql? user denied ? plz help me out to solve. ?

    - by user309381
    class MySQLDatabase { public $connection; function _construct() { $this->open_connection();} public function open_connection() {$this->connection = mysql_connect(DB_SERVER,DB_USER,DB_PASS); if(!$this->connection){die("Database Connection Failed" . mysql_error());} else{$db_select = mysql_select_db(DB_NAME,$this->connection); if(!$db_select){die("Database Selection Failed" . mysql_error()); } }} public function close_connection({ if(isset($this->connection)){ mysql_close($this->connection); unset($this->connection);}} public function query(/*$sql*/){ $sql = "SELECT*FROM users where id = 1"; $result = mysql_query($sql); $this->confirm_query($result); //return $result;while( $found_user = mysql_fetch_assoc($result)) { echo $found_user ['username']; } } private function confirm_query($result) { if(!$result) { die("The Query has problem" . mysql_error()); } } } $database = new MySQLDatabase(); $database->open_connection(); $database->query(); $database->close_connection(); I am getting error like denied for user system@locahost(using password no).i have also other database but it runs fine and i dont also i have set the password after encountered the error what else can do to solve plz help ?

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  • JavaApplicationStub with SWT causing problems

    - by mystro
    I created an application in Eclipse that uses SWT for the GUI. I've attempted to deploy the application using the Eclipse deploy, but it seems that when I do that, LSUIElement is not respected, and I can't force the application to disappear from the dock. Nonwhistanding that issue, the application actually deploys ok and is runnable. I attempted to deploy the application using Jar Bundler, but when I try to run the application, I get the following errors: 2010-06-09 21:44:02.564 JavaApplicationStub[89045:2003] * __NSAutoreleaseNoPool(): Object 0x10021f260 of class NSCFString autoreleased with no pool in place - just leaking 2010-06-09 21:44:02.568 JavaApplicationStub[89045:2003] * __NSAutoreleaseNoPool(): Object 0x10010a0a0 of class NSCFNumber autoreleased with no pool in place - just leaking 2010-06-09 21:44:02.569 JavaApplicationStub[89045:2003] * __NSAutoreleaseNoPool(): Object 0x1001127a0 of class NSCFString autoreleased with no pool in place - just leaking 2010-06-09 21:44:02.582 JavaApplicationStub[89045:2003] * __NSAutoreleaseNoPool(): Object 0x7fff70b7af70 of class NSCFString autoreleased with no pool in place - just leaking 2010-06-09 21:44:02.583 JavaApplicationStub[89045:2003] * __NSAutoreleaseNoPool(): Object 0x100123ea0 of class NSCFData autoreleased with no pool in place - just leaking 2010-06-09 21:44:02.587 JavaApplicationStub[89045:2003] * __NSAutoreleaseNoPool(): Object 0x100225b90 of class NSCFDictionary autoreleased with no pool in place - just leaking 2010-06-09 21:44:02.588 JavaApplicationStub[89045:2003] * __NSAutoreleaseNoPool(): Object 0x100225ee0 of class __NSFastEnumerationEnumerator autoreleased with no pool in place - just leaking in a very, very, very, long list. The application launches and appears to hang with the icon constantly bouncing in the dock, and the first GUI menu only partially loaded (it looks like one of the text boxes is semi visible, and the overall rectangle is the right size, but the GUI is not showing properly. It is essentially hung.) I'm hoping someone has had experience with this problem, and may be able to help! Thanks!

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  • custom collection in property grid

    - by guyl
    Hi guys. I'm using this article as a reference to use custom collection in propertygrid: LINK When I open the collectioneditor and remove all items then I press OK, I get an exception if null. How can i solve that ? I am using: public T this[int index] { get { if (List.Count == 0) { return default(T); } else { return (T)this.List[index]; } } } as a getter for an item, of course if I have no object how can i restart the whole collection ? this is the whole code /// <summary> /// A generic folder settings collection to use in a property grid. /// </summary> /// <typeparam name="T">can be import or export folder settings.</typeparam> [Serializable] [TypeConverter(typeof(FolderSettingsCollectionConverter)), Editor(typeof(FolderSettingsCollectionEditor), typeof(UITypeEditor))] public class FolderSettingsCollection_New<T> : CollectionBase, ICustomTypeDescriptor { private bool m_bRestrictNumberOfItems; private int m_bNumberOfItems; private Dictionary<string, int> m_UID2Idx = new Dictionary<string, int>(); private T[] arrTmp; /// <summary> /// C'tor, can determine the number of objects to hold. /// </summary> /// <param name="bRestrictNumberOfItems">restrict the number of folders to hold.</param> /// <param name="iNumberOfItems">The number of folders to hold.</param> public FolderSettingsCollection_New(bool bRestrictNumberOfItems = false , int iNumberOfItems = 1) { m_bRestrictNumberOfItems = bRestrictNumberOfItems; m_bNumberOfItems = iNumberOfItems; } /// <summary> /// Add folder to collection. /// </summary> /// <param name="t">Folder to add.</param> public void Add(T t) { if (m_bRestrictNumberOfItems) { if (this.List.Count >= m_bNumberOfItems) { return; } } int index = this.List.Add(t); if (t is WriteDataFolderSettings || t is ReadDataFolderSettings) { FolderSettingsBase tmp = t as FolderSettingsBase; m_UID2Idx.Add(tmp.UID, index); } } /// <summary> /// Remove folder to collection. /// </summary> /// <param name="t">Folder to remove.</param> public void Remove(T t) { this.List.Remove(t); if (t is WriteDataFolderSettings || t is ReadDataFolderSettings) { FolderSettingsBase tmp = t as FolderSettingsBase; m_UID2Idx.Remove(tmp.UID); } } /// <summary> /// Gets ot sets a folder. /// </summary> /// <param name="index">The index of the folder in the collection.</param> /// <returns>A folder object.</returns> public T this[int index] { get { //if (List.Count == 0) //{ // return default(T); //} //else //{ return (T)this.List[index]; //} } } /// <summary> /// Gets or sets a folder. /// </summary> /// <param name="sUID">The UID of the folder.</param> /// <returns>A folder object.</returns> public T this[string sUID] { get { if (this.Count == 0 || !m_UID2Idx.ContainsKey(sUID)) { return default(T); } else { return (T)this.List[m_UID2Idx[sUID]]; } } } /// <summary> /// /// </summary> /// <param name="sUID"></param> /// <returns></returns> public bool ContainsItemByUID(string sUID) { return m_UID2Idx.ContainsKey(sUID); } /// <summary> /// /// </summary> /// <returns></returns> public String GetClassName() { return TypeDescriptor.GetClassName(this, true); } /// <summary> /// /// </summary> /// <returns></returns> public AttributeCollection GetAttributes() { return TypeDescriptor.GetAttributes(this, true); } /// <summary> /// /// </summary> /// <returns></returns> public String GetComponentName() { return TypeDescriptor.GetComponentName(this, true); } /// <summary> /// /// </summary> /// <returns></returns> public TypeConverter GetConverter() { return TypeDescriptor.GetConverter(this, true); } /// <summary> /// /// </summary> /// <returns></returns> public EventDescriptor GetDefaultEvent() { return TypeDescriptor.GetDefaultEvent(this, true); } /// <summary> /// /// </summary> /// <returns></returns> public PropertyDescriptor GetDefaultProperty() { return TypeDescriptor.GetDefaultProperty(this, true); } /// <summary> /// /// </summary> /// <param name="editorBaseType"></param> /// <returns></returns> public object GetEditor(Type editorBaseType) { return TypeDescriptor.GetEditor(this, editorBaseType, true); } /// <summary> /// /// </summary> /// <param name="attributes"></param> /// <returns></returns> public EventDescriptorCollection GetEvents(Attribute[] attributes) { return TypeDescriptor.GetEvents(this, attributes, true); } /// <summary> /// /// </summary> /// <returns></returns> public EventDescriptorCollection GetEvents() { return TypeDescriptor.GetEvents(this, true); } /// <summary> /// /// </summary> /// <param name="pd"></param> /// <returns></returns> public object GetPropertyOwner(PropertyDescriptor pd) { return this; } /// <summary> /// /// </summary> /// <param name="attributes"></param> /// <returns></returns> public PropertyDescriptorCollection GetProperties(Attribute[] attributes) { return GetProperties(); } /// <summary> /// Called to get the properties of this type. /// </summary> /// <returns></returns> public PropertyDescriptorCollection GetProperties() { // Create a collection object to hold property descriptors PropertyDescriptorCollection pds = new PropertyDescriptorCollection(null); // Iterate the list of employees for (int i = 0; i < this.List.Count; i++) { // Create a property descriptor for the employee item and add to the property descriptor collection CollectionPropertyDescriptor_New<T> pd = new CollectionPropertyDescriptor_New<T>(this, i); pds.Add(pd); } // return the property descriptor collection return pds; } public T[] ToArray() { if (arrTmp == null) { arrTmp = new T[List.Count]; for (int i = 0; i < List.Count; i++) { arrTmp[i] = (T)List[i]; } } return arrTmp; } } /// <summary> /// Enable to display data about a collection in a property grid. /// </summary> /// <typeparam name="T">Folder object.</typeparam> public class CollectionPropertyDescriptor_New<T> : PropertyDescriptor { private FolderSettingsCollection_New<T> collection = null; private int index = -1; /// <summary> /// /// </summary> /// <param name="coll"></param> /// <param name="idx"></param> public CollectionPropertyDescriptor_New(FolderSettingsCollection_New<T> coll, int idx) : base("#" + idx.ToString(), null) { this.collection = coll; this.index = idx; } /// <summary> /// /// </summary> public override AttributeCollection Attributes { get { return new AttributeCollection(null); } } /// <summary> /// /// </summary> /// <param name="component"></param> /// <returns></returns> public override bool CanResetValue(object component) { return true; } /// <summary> /// /// </summary> public override Type ComponentType { get { return this.collection.GetType(); } } /// <summary> /// /// </summary> public override string DisplayName { get { if (this.collection[index] != null) { return this.collection[index].ToString(); } else { return null; } } } public override string Description { get { return ""; } } /// <summary> /// /// </summary> /// <param name="component"></param> /// <returns></returns> public override object GetValue(object component) { if (this.collection[index] != null) { return this.collection[index]; } else { return null; } } /// <summary> /// /// </summary> public override bool IsReadOnly { get { return false; } } public override string Name { get { return "#" + index.ToString(); } } /// <summary> /// /// </summary> public override Type PropertyType { get { return this.collection[index].GetType(); } } public override void ResetValue(object component) { } /// <summary> /// /// </summary> /// <param name="component"></param> /// <returns></returns> public override bool ShouldSerializeValue(object component) { return true; } /// <summary> /// /// </summary> /// <param name="component"></param> /// <param name="value"></param> public override void SetValue(object component, object value) { // this.collection[index] = value; } }

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  • What is the best practice in regards to building composite dtos off of an aggregate root with domain

    - by Chance
    I'm trying to figure out the best approach/practice for assembling a composite data transfer object off of an aggregate root and would love to hear people's thoughts on this. For example, lets say I have a root that has a few domain objects as children. I want to assemble a specific view dto, based on some business logic, that either has attributes or full dto's of it's objects. What I'm struggling with is trying to figure out where that assembly should happen. I can see it going on the domain object of the aggregate root as there is some business logic associated with it. The benefits of this approach from what I've deduced thus far is that it should reduce the inevitable business logic from bleeding outisde of the domain object. It also allows for private methods that take care of tasks that could become more complex from an external builder. The downsides being that the domain object becomes much more entrenched in the application's workflow and represents much more than just the domain object. It also could become very large in the scenario where you need multiple composite Dtos. Alternatively, I could also see it belonging to some form of transfer object assembler where there is a builder for each domain object. The domain objects would still be responsible for GetDto() and UpdateFromDto(dto). Outside of that, the builder would handle the construction and deconstruction of composite dtos. The downside is kind of mentioned above, where I fear this will easily lead to developers unfamiliar with DDD bleeding a ton of business logic into the assembler which is what I want to desperately avoid. Any thoughts would be greatly apperciated.

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  • How to enforce users to create objects of class derived from mine with "new" only?

    - by sharptooth
    To implement reference counting we use an IUnknown-like interface and a smart pointer template class. The interface has implementation for all the reference-count methods, including Release(): void IUnknownLike::Release() { if( --refCount == 0 ) { delete this; } } The smart pointer template class has a copy constructor and an assignment operator both accepting raw pointers. So users can do the following: class Class : public IUnknownLike { }; void someFunction( CSmartPointer<Class> object ); //whatever function Class object; someFunction( &object ); and the program runs into undefined behavior - the object is created with reference count zero, the smart pointer is constructed and bumps it to one, then the function returns, smart pointer is destroyed, calls Release() which leads to delete of a stack-allocated variable. Users can as well do the following: struct COuter { //whatever else; Class inner;// IUnknownLike descendant }; COuter object; somefunction( &object.Inner ); and again an object not created with new is deleted. Undefined behavior at its best. Is there any way to change the IUnknownLike interface so that the user is forced to use new for creating all objects derived from IUnknownLike - both directly derived and indirectly derived (with classes in between the most derived and the base)?

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  • Using Excel VBA to Create SQL Tables

    - by user307655
    Hi All, I am trying to use Excel VBA to automate the creation of a SQL table in an existing SQL Database. I have come across the following code on this side. Private Sub CreateDatabaseFromExcel() Dim dbConnectStr As String Dim Catalog As Object Dim cnt As ADODB.Connection Dim dbPath As String Dim tblName As String 'Set database name in the Excel Sheet dbPath = ActiveSheet.Range("B1").Value 'Database Name tblName = ActiveSheet.Range("B2").Value 'Table Name dbConnectStr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & dbPath & ";" 'Create new database using name entered in Excel Cell ("B1") Set Catalog = CreateObject("ADOX.Catalog") Catalog.Create dbConnectStr Set Catalog = Nothing 'Connect to database and insert a new table Set cnt = New ADODB.Connection With cnt .Open dbConnectStr .Execute "CREATE TABLE tblName ([BankName] text(50) WITH Compression, " & _ "[RTNumber] text(9) WITH Compression, " & _ "[AccountNumber] text(10) WITH Compression, " & _ "[Address] text(150) WITH Compression, " & _ "[City] text(50) WITH Compression, " & _ "[ProvinceState] text(2) WITH Compression, " & _ "[Postal] text(6) WITH Compression, " & _ "[AccountAmount] decimal(6))" End With Set cnt = Nothing End Sub However i can't successfully get it to work? What I am trying to do is actually use Excel to create a table not a database? The database already exists. I would just like to create a new table. The name of the table will be referenced from cell A1 in Sheet 1. Can somebody please help. Thanks Regards Gerard

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  • Is this a good decorator pattern for javascript?

    - by Kucebe
    I need some simple objects that could become more complex later, with many different properties, so i thought to decorator pattern. I made this looking at Crockford's power constructor and object augmentation: //add property to object Object.prototype.addProperty = function(name, func){ for(propertyName in this){ if(propertyName == name){ throw new Error(propertyName + " is already defined"); } } this[name] = func; }; //constructor of base object var BaseConstructor = function(param){ var _privateVar = param; return{ getPrivateVar: function(){ return _privateVar; } }; }; //a simple decorator, adds one private attribute and one privileged method var simpleDecorator = function(obj, param){ var _privateVar = param; var privilegedMethod1 = function(){ return "privateVar of decorator is: " + _privateVar; }; obj.addProperty("privilegedMethod1", privilegedMethod1); return obj; } //a more complex decorator, adds public and private properties var complexDecorator = function(obj, param1, param2){ //private properties var _privateVar = param1; var _privateMethod = function(x){ for(var i=0; i<x; i++){ _privateVar += x; } return _privateVar; }; //public properties var publicVar = "I'm public"; obj.addProperty("publicVar", publicVar); var privilegedMethod2 = function(){ return _privateMethod(param2); }; obj.addProperty("privilegedMethod2", privilegedMethod2); var publicMethod = function(){ var temp = this.privilegedMethod2(); return "do something: " + temp + " - publicVar is: " + this.publicVar; }; obj.addProperty("publicMethod", publicMethod); return obj; } //new basic object var myObj = BaseConstructor("obj1"); //the basic object will be decorated var myObj = simpleDecorator(obj, "aParam"); //the basic object will be decorated with other properties var myObj = complexDecorator(obj, 2, 3); Is this a good way to have Decorator Pattern in javascript? Are there other better ways to do this?

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  • What is wrong with locking non-static fields? What is the correct way to lock a particular instance?

    - by smartcaveman
    Why is it considered bad practice to lock non-static fields? And, if I am not locking non-static fields, then how do I lock an instance method without locking the method on all other instances of the same or derived class? I wrote an example to make my question more clear. public abstract class BaseClass { private readonly object NonStaticLockObject = new object(); private static readonly object StaticLockObject = new object(); protected void DoThreadSafeAction<T>(Action<T> action) where T: BaseClass { var derived = this as T; if(derived == null) { throw new Exception(); } lock(NonStaticLockObject) { action(derived); } } } public class DerivedClass :BaseClass { private readonly Queue<object> _queue; public void Enqueue(object obj) { DoThreadSafeAction<DerivedClass>(x=>x._queue.Enqueue(obj)); } } If I make the lock on the StaticLockObject, then the DoThreadSafeAction method will be locked for all instances of all classes that derive from BaseClass and that is not what I want. I want to make sure that no other threads can call a method on a particular instance of an object while it is locked.

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  • C# Event Handlers Using an Enum

    - by Jimbo
    I have a StatusChanged event that is raised by my object when its status changes - however, the application needs to carry out additional actions based on what the new status is. e.g If the new status is Disconnected, then it must update the status bar text and send an email notification. So, I wanted to create an Enum with the possible statuses (Connected, Disconnected, ReceivingData, SendingData etc.) and have that sent with the EventArgs parameter of the event when it is raised (see below) Define the object: class ModemComm { public event CommanderEventHandler ModemCommEvent; public delegate void CommanderEventHandler(object source, ModemCommEventArgs e); public void Connect() { ModemCommEvent(this, new ModemCommEventArgs ModemCommEventArgs.eModemCommEvent.Connected)); } } Define the new EventArgs parameter: public class ModemCommEventArgs : EventArgs{ public enum eModemCommEvent { Idle, Connected, Disconnected, SendingData, ReceivingData } public eModemCommEvent eventType { get; set; } public string eventMessage { get; set; } public ModemCommEventArgs(eModemCommEvent eventType, string eventMessage) { this.eventMessage = eventMessage; this.eventType = eventType; } } I then create a handler for the event in the application: ModemComm comm = new ModemComm(); comm.ModemCommEvent += OnModemCommEvent; and private void OnModemCommEvent(object source, ModemCommEventArgs e) { } The problem is, I get a 'Object reference not set to an instance of an object' error when the object attempts to raise the event. Hoping someone can explain in n00b terms why and how to fix it :)

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  • PHP Exceptions in Classes

    - by mike condiff
    I'm writing a web application (PHP) for my friend and have decided to use my limited OOP training from Java. My question is what is the best way to note in my class/application that specific critical things failed without actually breaking my page. Currently my problem is I have an Object "SummerCamper" which takes a camper_id as it's argument to load all of the necessary data into the object from the database. Say someone specifies a camper_id in the querystring that does not exist, I pass it to my objects constructor and the load fails. Currently I don't see a way for me to just return false from the constructor. I have read I could possibly do this with Exceptions, throwing an exception if no records are found in the database or if some sort of validation fails on input of the camper_id from the application etc. However, I have not really found a great way to alert my program that the Object Load has failed. I tried returning false from within the CATCH but the Object still persists in my php page. I do understand I could put a variable $is_valid = false if the load fails and then check the Object using a get method but I think there may be better ways. What is the best way of achieving the essential termination of an object if a load fails? Should I load data into the object from outside the constructor? Is there some osrt of design pattern that I should look into? Any help would be appreciated.

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