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• What's the most DRY-appropriate way to execute an SQL command?

  - by Sean U

  I'm looking to figure out the best way to execute a database query using the least amount of boilerplate code. The method suggested in the SqlCommand documentation: private static void ReadOrderData(string connectionString) { string queryString = "SELECT OrderID, CustomerID FROM dbo.Orders;"; using (SqlConnection connection = new SqlConnection(connectionString)) { SqlCommand command = new SqlCommand(queryString, connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); try { while (reader.Read()) { Console.WriteLine(String.Format("{0}, {1}", reader[0], reader[1])); } } finally { reader.Close(); } } } mostly consists of code that would have to be repeated in every method that interacts with the database. I'm already in the habit of factoring out the establishment of a connection, which would yield code more like the following. (I'm also modifying it so that it returns data, in order to make the example a bit less trivial.) private SQLConnection CreateConnection() { var connection = new SqlConnection(_connectionString); connection.Open(); return connection; } private List<int> ReadOrderData() { using(var connection = CreateConnection()) using(var command = connection.CreateCommand()) { command.CommandText = "SELECT OrderID FROM dbo.Orders;"; using(var reader = command.ExecuteReader()) { var results = new List<int>(); while(reader.Read()) results.Add(reader.GetInt32(0)); return results; } } } That's an improvement, but there's still enough boilerplate to nag at me. Can this be reduced further? In particular, I'd like to do something about the first two lines of the procedure. I don't feel like the method should be in charge of creating the SqlCommand. It's a tiny piece of repetition as it is in the example, but it seems to grow if transactions are being managed manually or timeouts are being altered or anything like that.

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• How to use Hibernate SchemaUpdate class with a JPA persistence.xml?

  - by John Rizzo

  I've a main method using SchemaUpdate to display at the console what tables to alter/create and it works fine in my Hibernate project: public static void main(String[] args) throws IOException { //first we prepare the configuration Properties hibProps = new Properties(); hibProps.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("jbbconfigs.properties")); Configuration cfg = new AnnotationConfiguration(); cfg.configure("/hibernate.cfg.xml").addProperties(hibProps); //We create the SchemaUpdate thanks to the configs SchemaUpdate schemaUpdate = new SchemaUpdate(cfg); //The update is executed in script mode only schemaUpdate.execute(true, false); ... I'd like to reuse this code in a JPA project, having no hibernate.cfg.xml file (and no .properties file), but a persistence.xml file (autodetected in the META-INF directory as specified by the JPA spec). I tried this too simple adaptation, Configuration cfg = new AnnotationConfiguration(); cfg.configure(); but it failed with that exception. Exception in thread "main" org.hibernate.HibernateException: /hibernate.cfg.xml not found Has anybody done that? Thanks.

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• PHP + CURL How to get file name

  - by Gunjan

  I'm trying to download users profile picture from facebook in PHP using this function public static function downloadFile($url, $options = array()) { if (!is_array($options)) $options = array(); $options = array_merge(array( 'connectionTimeout' => 5, // seconds 'timeout' => 10, // seconds 'sslVerifyPeer' => false, 'followLocation' => true, // if true, limit recursive redirection by 'maxRedirs' => 2, // setting value for "maxRedirs" ), $options); // create a temporary file (we are assuming that we can write to the system's temporary directory) $tempFileName = tempnam(sys_get_temp_dir(), ''); $fh = fopen($tempFileName, 'w'); $curl = curl_init($url); curl_setopt($curl, CURLOPT_FILE, $fh); curl_setopt($curl, CURLOPT_CONNECTTIMEOUT, $options['connectionTimeout']); curl_setopt($curl, CURLOPT_TIMEOUT, $options['timeout']); curl_setopt($curl, CURLOPT_HEADER, false); curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, $options['sslVerifyPeer']); curl_setopt($curl, CURLOPT_FOLLOWLOCATION, $options['followLocation']); curl_setopt($curl, CURLOPT_MAXREDIRS, $options['maxRedirs']); curl_exec($curl); curl_close($curl); fclose($fh); return $tempFileName; } The problem is it saves the file in the /tmp directory with a random name and without the extension. How can I get the original name of the file (I'm more interested in the original extension) The important things here are: The url actually redirects to image so i cant get it from original url the final url does not have the file name in headers

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• Why should I override hashCode() when I override equals() method?

  - by Bragaadeesh

  Ok, I have heard from many places and sources that whenever I override the equals() method, I need to override the hashCode() method as well. But consider the following piece of code package test; public class MyCustomObject { int intVal1; int intVal2; public MyCustomObject(int val1, int val2){ intVal1 = val1; intVal2 = val2; } public boolean equals(Object obj){ return (((MyCustomObject)obj).intVal1 == this.intVal1) && (((MyCustomObject)obj).intVal2 == this.intVal2); } public static void main(String a[]){ MyCustomObject m1 = new MyCustomObject(3,5); MyCustomObject m2 = new MyCustomObject(3,5); MyCustomObject m3 = new MyCustomObject(4,5); System.out.println(m1.equals(m2)); System.out.println(m1.equals(m3)); } } Here the output is true, false exactly the way I want it to be and I dont care of overriding the hashCode() method at all. This means that hashCode() overriding is an option rather being a mandatory one as everyone says. I want a second confirmation.

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• C# functional quicksort is failing

  - by Rubys

  I'm trying to implement quicksort in a functional style using C# using linq, and this code randomly works/doesn't work, and I can't figure out why. Important to mention: When I call this on an array or list, it works fine. But on an unknown-what-it-really-is IEnumerable, it goes insane (loses values or crashes, usually. sometimes works.) The code: public static IEnumerable<T> Quicksort<T>(this IEnumerable<T> source) where T : IComparable<T> { if (!source.Any()) yield break; var pivot = source.First(); var sortedQuery = source.Skip(1).Where(a => a.CompareTo(source.First()) <= 0).Quicksort() .Concat(new[] { pivot }) .Concat(source.Skip(1).Where(a => a.CompareTo(source.First()) > 0).Quicksort()); foreach (T key in sortedQuery) yield return key; } Can you find any faults here that would cause this to fail?

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• MyController class must produce class according to the enum type.

  - by programmerist

  GenoTipController must produce class according to the enum type. i have 3 class: _Company,_Muayene,_Radyoloji. Also i have CompanyView Class GetPersonel method. if you look GenoTipController my codes need refactoring. Can you understand me? i need a class according to ewnum type must me produce class. For example; case DataModelType.Radyoloji it must return radyoloji= new Radyoloji . Everything must be one switch case? public class GenoTipController { public _Company GenerateCompany(DataModelType modeltype) { _Company company = null; switch (modeltype) { case DataModelType.Radyoloji: break; case DataModelType.Satis: break; case DataModelType.Muayene: break; case DataModelType.Company: company = new Company(); break; default: break; } return company; } public _Muayene GenerateMuayene(DataModelType modeltype) { _Muayene muayene = null; switch (modeltype) { case DataModelType.Radyoloji: break; case DataModelType.Satis: break; case DataModelType.Muayene: muayene = new Muayene(); break; case DataModelType.Company: break; default: break; } return muayene; } public _Radyoloji GenerateRadyoloji(DataModelType modeltype) { _Radyoloji radyoloji = null; switch (modeltype) { case DataModelType.Radyoloji: radyoloji = new Radyoloji(); break; case DataModelType.Satis: break; case DataModelType.Muayene: break; case DataModelType.Company: break; default: break; } return radyoloji; } } public class CompanyView { public static List GetPersonel() { GenoTipController controller = new GenoTipController(); _Company company = controller.GenerateCompany(DataModelType.Company); return company.GetPersonel(); } } public enum DataModelType { Radyoloji, Satis, Muayene, Company } }

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• How to do buffered intersection checks on an IPoint?

  - by Quigrim

  How would I buffer an IPoint to do an intersection check using IRelationalOperator? I have, for arguments sake: IPoint p1 = xxx; IPoint p2 = yyy; IRelationalOperator rel1 = (IRelationalOperator)p1; if (rel.Intersects (p2)) // Do something But now I want to add a tolerance to my check, so I assume the right way to do that is by either buffering p1 or p2. Right? How do I add such a buffer? Note: the Intersects method I am using is an extension method I wrote to simplify my code. Here it is: /// <summary> /// Returns true if the IGeometry is intersected. /// This method negates the Disjoint method. /// </summary> /// <param name="relOp">The rel op.</param> /// <param name="other">The other.</param> /// <returns></returns> public static bool Intersects ( this IRelationalOperator relOp, IGeometry other) { return (!relOp.Disjoint (other)); }

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• std::conditional compile-time branch evaluation

  - by cmannett85

  Compiling this: template < class T, class Y, class ...Args > struct isSame { static constexpr bool value = std::conditional< sizeof...( Args ), typename std::conditional< std::is_same< T, Y >::value, isSame< Y, Args... >, // Error! std::false_type >::type, std::is_same< T, Y > >::type::value; }; int main() { qDebug() << isSame< double, int >::value; return EXIT_SUCCESS; } Gives me this compiler error: error: wrong number of template arguments (1, should be 2 or more) The issue is that isSame< double, int > has an empty Args parameter pack, so isSame< Y, Args... > effectively becomes isSame< Y > which does not match the signature. But my question is: Why is that branch being evaluated at all? sizeof...( Args ) is false, so the inner std:conditional should not be evaluated. This isn't a runtime piece of code, the compiler knows that sizeof..( Args ) will never be true with the given template types. If you're curious, it's supposed to be a variadic version of std::is_same, not that it works...

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• Multiple dispatching issue

  - by user1440263

  I try to be synthetic: I'm dispatching an event from a MovieClip (customized symbol in library) this way: public function _onMouseDown(e:MouseEvent){ var obj = {targetClips:["tondo"],functionString:"testFF"}; dispatchEvent(new BridgeEvent(BridgeEvent.BRIDGE_DATA,obj)); } The BridgeEvent class is the following: package events { import flash.events.EventDispatcher; import flash.events.Event; public class BridgeEvent extends Event { public static const BRIDGE_DATA:String = "BridgeData"; public var data:*; public function BridgeEvent(type:String, data:*) { this.data = data; super(type, true); } } } The document class listens to the event this way: addEventListener(BridgeEvent.BRIDGE_DATA,eventSwitcher); In eventSwitcher method I have a simple trace("received"). What happens: when I click the MovieClip the trace action gets duplicated and the output window writes many "received" (even if the click is only one). What happens? How do I prevent this behaviour? What is causing this? Any help is appreciated. [SOLVED] I'm sorry, you will not believe this. A colleague, to make me a joke, converted the MOUSE_DOWN handler to MOUSE_OVER.

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• Set size of JTable in JScrollPane and in JPanel with the size of the JFrame

  - by user1761818

  I want the table with the same width as the frame and also when I resize the frame the table need to be resized too. I think setSize() of JTable doesn't work correctly. Can you help me? import java.awt.Color; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.SwingUtilities; public class Main extends JFrame { public Main() { setSize(400, 600); String[] columnNames = {"A", "B", "C"}; Object[][] data = { {"Moni", "adsad", 2}, {"Jhon", "ewrewr", 4}, {"Max", "zxczxc", 6} }; JTable table = new JTable(data, columnNames); JScrollPane tableSP = new JScrollPane(table); int A = this.getWidth(); int B = this.getHeight(); table.setSize(A, B); JPanel tablePanel = new JPanel(); tablePanel.add(tableSP); tablePanel.setBackground(Color.red); add(tablePanel); setTitle("Marks"); setLocationRelativeTo(null); setDefaultCloseOperation(EXIT_ON_CLOSE); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { Main ex = new Main(); ex.setVisible(true); } }); } }

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• Using libgrib2c in c++ application, linker error "Undefined reference to..."

  - by Rich

  EDIT: If you're going to be doing things with GRIB files I would recommend the GDAL library which is backed by the Open Source Geospatial Foundation. You will save yourself a lot of headache :) I'm using Qt creator in Ubuntu creating a c++ app. I am attempting to use an external lib, libgrib2c.a, that has a header grib2.h. Everything compiles, but when it tries to link I get the error: undefined reference to 'seekgb(_IO_FILE*, long, long, long*, long*) I have tried wrapping the header file with: extern "C"{ #include "grib2.h" } But it didn't fix anything so I figured that was not my problem. In the .pro file I have the line: include($${ROOT}/Shared/common/commonLibs.pri) and in commonLibs.pri I have: INCLUDEPATH+=$${ROOT}/external_libs/g2clib/include LIBS+=-L$${ROOT}/external_libs/g2clib/lib LIBS+=-lgrib2c I am not encountering an error finding the library. If I do a nm command on the libgrib2c.a I get: nm libgrib2c.a | grep seekgb seekgb.o: 00000000 T seekgb And when I run qmake with the additional argument of LIBS+=-Wl,--verbose I can find the lib file in the output: attempt to open /usr/lib/libgrib2c.so failed attempt to open /usr/lib/libgrib2c.a failed attempt to open /mnt/sdb1/ESMF/App/ESMF_App/../external_libs/linux/qwt_6.0.2/lib/libgrib2c.so failed attempt to open /mnt/sdb1/ESMF/App/ESMF_App/../external_libs/linux/qwt_6.0.2/lib/libgrib2c.a failed attempt to open ..//Shared/Config/lib/libgrib2c.so failed attempt to open ..//Shared/Config/lib/libgrib2c.a failed attempt to open ..//external_libs/libssh2/lib/libgrib2c.so failed attempt to open ..//external_libs/libssh2/lib/libgrib2c.a failed attempt to open ..//external_libs/openssl/lib/libgrib2c.so failed attempt to open ..//external_libs/openssl/lib/libgrib2c.a failed attempt to open ..//external_libs/g2clib/lib/libgrib2c.so failed attempt to open ..//external_libs/g2clib/lib/libgrib2c.a succeeded Although it doesn't show any of the .o files in the library is this because it is a c library in my c++ app? in the .cpp file that I am trying to use the library I have: #include "gribreader.h" #include <stdio.h> #include <stdlib.h> #include <external_libs/g2clib/include/grib2.h> #include <Shared/logging/Logger.hpp> //------------------------------------------------------------------------------ /// Opens a GRIB file from disk. /// /// This function opens the grib file and searches through it for how many GRIB /// messages are contained as well as their starting locations. /// /// \param a_filePath. The path to the file to be opened. /// \return True if successful, false if not. //------------------------------------------------------------------------------ bool GRIBReader::OpenGRIB(std::string a_filePath) { LOG(notification)<<"Attempting to open grib file: "<< a_filePath; if(isOpen()) { CloseGRIB(); } m_filePath = a_filePath; m_filePtr = fopen(a_filePath.c_str(), "r"); if(m_filePtr == NULL) { LOG(error)<<"Unable to open file: " << a_filePath; return false; } LOG(notification)<<"Successfully opened GRIB file"; g2int currentMessageSize(1); g2int seekPosition(0); g2int lengthToBeginningOfGrib(0); g2int seekLength(32000); int i(0); int iterationLimit(300); m_GRIBMessageLocations.clear(); m_GRIBMessageSizes.clear(); while(i < iterationLimit) { seekgb(m_filePtr, seekPosition, seekLength, &lengthToBeginningOfGrib, &currentMessageSize); if(currentMessageSize != 0) { LOG(verbose) << "Adding GRIB message location " << lengthToBeginningOfGrib << " with length " << currentMessageSize; m_GRIBMessageLocations.push_back(lengthToBeginningOfGrib); m_GRIBMessageSizes.push_back(currentMessageSize); seekPosition = lengthToBeginningOfGrib + currentMessageSize; LOG(verbose) << "GRIB seek position moved to " << seekPosition; } else { LOG(notification)<<"End of GRIB file found, after "<< i << " GRIB messages."; break; } } if(i >= iterationLimit) { LOG(warning) << "The iteration limit of " << iterationLimit << "was reached while searching for GRIB messages"; } return true; } And the header grib2.h is as follows: #ifndef _grib2_H #define _grib2_H #include<stdio.h> #define G2_VERSION "g2clib-1.4.0" #ifdef __64BIT__ typedef int g2int; typedef unsigned int g2intu; #else typedef long g2int; typedef unsigned long g2intu; #endif typedef float g2float; struct gtemplate { g2int type; /* 3=Grid Defintion Template. */ /* 4=Product Defintion Template. */ /* 5=Data Representation Template. */ g2int num; /* template number. */ g2int maplen; /* number of entries in the static part */ /* of the template. */ g2int *map; /* num of octets of each entry in the */ /* static part of the template. */ g2int needext; /* indicates whether or not the template needs */ /* to be extended. */ g2int extlen; /* number of entries in the template extension. */ g2int *ext; /* num of octets of each entry in the extension */ /* part of the template. */ }; typedef struct gtemplate gtemplate; struct gribfield { g2int version,discipline; g2int *idsect; g2int idsectlen; unsigned char *local; g2int locallen; g2int ifldnum; g2int griddef,ngrdpts; g2int numoct_opt,interp_opt,num_opt; g2int *list_opt; g2int igdtnum,igdtlen; g2int *igdtmpl; g2int ipdtnum,ipdtlen; g2int *ipdtmpl; g2int num_coord; g2float *coord_list; g2int ndpts,idrtnum,idrtlen; g2int *idrtmpl; g2int unpacked; g2int expanded; g2int ibmap; g2int *bmap; g2float *fld; }; typedef struct gribfield gribfield; /* Prototypes for unpacking API */ void seekgb(FILE *,g2int ,g2int ,g2int *,g2int *); g2int g2_info(unsigned char *,g2int *,g2int *,g2int *,g2int *); g2int g2_getfld(unsigned char *,g2int ,g2int ,g2int ,gribfield **); void g2_free(gribfield *); /* Prototypes for packing API */ g2int g2_create(unsigned char *,g2int *,g2int *); g2int g2_addlocal(unsigned char *,unsigned char *,g2int ); g2int g2_addgrid(unsigned char *,g2int *,g2int *,g2int *,g2int ); g2int g2_addfield(unsigned char *,g2int ,g2int *, g2float *,g2int ,g2int ,g2int *, g2float *,g2int ,g2int ,g2int *); g2int g2_gribend(unsigned char *); /* Prototypes for supporting routines */ extern double int_power(double, g2int ); extern void mkieee(g2float *,g2int *,g2int); void rdieee(g2int *,g2float *,g2int ); extern gtemplate *getpdstemplate(g2int); extern gtemplate *extpdstemplate(g2int,g2int *); extern gtemplate *getdrstemplate(g2int); extern gtemplate *extdrstemplate(g2int,g2int *); extern gtemplate *getgridtemplate(g2int); extern gtemplate *extgridtemplate(g2int,g2int *); extern void simpack(g2float *,g2int,g2int *,unsigned char *,g2int *); extern void compack(g2float *,g2int,g2int,g2int *,unsigned char *,g2int *); void misspack(g2float *,g2int ,g2int ,g2int *, unsigned char *, g2int *); void gbit(unsigned char *,g2int *,g2int ,g2int ); void sbit(unsigned char *,g2int *,g2int ,g2int ); void gbits(unsigned char *,g2int *,g2int ,g2int ,g2int ,g2int ); void sbits(unsigned char *,g2int *,g2int ,g2int ,g2int ,g2int ); int pack_gp(g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *, g2int *); #endif /* _grib2_H */ I have been scratching my head for two days on this. If anyone has an idea on what to do or can point me in some sort of direction, I'm stumped. Also, if you have any comments on how I can improve this post I'd love to hear them, kinda new at this posting thing. Usually I'm able to find an answer in the vast stores of knowledge already contained on the web.

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• Spring 3 MVC validation BindingResult doesn't contain any errors

  - by Travelsized

  I'm attempting to get a Spring 3.0.2 WebMVC project running with the new annotated validation support. I have a Hibernate entity annotated like this: @Entity @Table(name = "client") public class Client implements Serializable { private static final long serialVersionUID = 1L; @Id @Basic(optional = false) @Column(name = "clientId", nullable = false) @NotEmpty private Integer clientId; @Basic(optional = false) @Column(name = "firstname", nullable = false, length = 45) @NotEmpty @Size(min=2, max=45) private String firstname; ... more fields, getters and setters } I've turned on mvc annotation support in my applicationContext.xml file: <mvc:annotation-driven /> And I have a method in my controller that responds to a form submission: @RequestMapping(value="/addClient.htm") public String addClient(@ModelAttribute("client") @Valid Client client, BindingResult result) { if(result.hasErrors()) { return "addClient"; } service.storeClient(client); return "clientResult"; } When my app loads in the server, I can see in the server log file that it loads a validator: 15 [http-8084-2] INFO org.hibernate.validator.util.Version - Hibernate Validator 4.0.2.GA The problem I'm having is that the validator doesn't seem to kick in. I turned on the debugger, and when I get into the controller method, the BindingResult contains 0 errors after I submit an empty form. (The BindingResult does show that it contains the Client object as a target.) It then proceeds to insert a record without an Id and throws an exception. If I fill out an Id but leave the name blank, it creates a record with the Id and empty fields. What steps am I missing to get the validation working?

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• How can you push a new view with a grouped table?

  - by Tanner

  Hi All, Ive been trying to push a new view when a cell is tapped but absolutely nothing happens. I figured grouped style pushed the same as plain. Here is my code: -(void)viewDidLoad { [super viewDidLoad]; contactArray = [[NSArray alloc] initWithObjects:@"iPhone",@"iPod",@"MacBook",@"MacBook Pro",nil]; shareArray = [[NSArray alloc] initWithObjects:@"Flex",@"AIR",@"PhotoShop",@"Flash",nil]; } -(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 2; } // Customize the number of rows in the table view. -(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { if(section == 0) return [contactArray count]; else return [shareArray count]; } -(NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section{ if(section == 0){ return @"Contact"; }else{ return @"Share"; } } -(NSString *)tableView:(UITableView *)tableView titleForFooterInSection:(NSInteger)section{ if(section == 0){ return @"Footer for Apple Products"; }else{ return @"Footer for Adobe Softwares"; } } // Customize the appearance of table view cells. -(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease]; } // Set up the cell... if(indexPath.section == 0){ cell.text = [contactArray objectAtIndex:indexPath.row]; }else{ cell.text = [shareArray objectAtIndex:indexPath.row]; } return cell; } -(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { //NextViewController *nextController = [[NextViewController alloc] initWithNibName:@"NextView" bundle:nil]; //[self.navigationController pushViewController:nextController animated:YES]; if([contactArray objectAtIndex:indexPath.row] == @"iPhone"){ LandscapeHydrogen *abo = [[LandscapeHydrogen alloc] initWithNibName:@"LandscapeHydrogen" bundle:nil]; [self.navigationController pushViewController:abo animated:NO]; [abo release]; } } Any help is appreciated.

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• Checking instance of non-class constrained type parameter for null in generic method

  - by casperOne

  I currently have a generic method where I want to do some validation on the parameters before working on them. Specifically, if the instance of the type parameter T is a reference type, I want to check to see if it's null and throw an ArgumentNullException if it's null. Something along the lines of: // This can be a method on a generic class, it does not matter. public void DoSomething<T>(T instance) { if (instance == null) throw new ArgumentNullException("instance"); Note, I do not wish to constrain my type parameter using the class constraint. I thought I could use Marc Gravell's answer on "How do I compare a generic type to its default value?", and use the EqualityComparer<T> class like so: static void DoSomething<T>(T instance) { if (EqualityComparer<T>.Default.Equals(instance, null)) throw new ArgumentNullException("instance"); But it gives a very ambiguous error on the call to Equals: Member 'object.Equals(object, object)' cannot be accessed with an instance reference; qualify it with a type name instead How can I check an instance of T against null when T is not constrained on being a value or reference type?

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• How to Implement Custom List View for the list Items in Android Application

  - by avadhani

  I had a problem with the list view having both parent list and the child list of the list activity(implemented through database query). I wish to show them differing their properties by changing the text style (parent list items are in bold, child list items are in normal style). The following is the code from which all the child and parent list items having the same style(bold): String sql = "SELECT Parentid,Childid,Name from (select com.Parentid, com.Childid, com.Name from table1 mem inner join table2 cd on mem.column1=cd.column1 inner join table3 com on com.childid = mem.childid where Parentid is NULL UNION SELECT com.Parentid, com.Childid,com.Name from table1 mem inner join table3 com on com.childid = mem.childid inner join table2 cd on mem.column1=cd.column1 where Parentid is NOT NULL) a group by Parentid, Childid;"; Cursor cdata = myDbHelper.getView(sql); and the List Adapter is: private static final String fields[] = {"Name"}; int[] names = new int[] {R.id.name}; SimpleCursorAdapter adapter2 = new SimpleCursorAdapter(this,R.layout.clientlist1, cdata, fields,names ); and the clientlist.xml is: <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="fill_parent" android:id="@+id/MainLayout" android:padding="5px"> <TextView android:id="@+id/name" android:layout_alignParentRight="true" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textSize="12sp" android:textColor="#104082" android:textStyle="bold" android:layout_weight="1" /> From this i am getting the list having the complete list having both parent and child list items in a single list view. I wish to differ in their text style(bold, normal) for parent and child items respectively. Please help me with the code/links. Thanks a lot in advance.

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• i have problem with sharing a folder through programming using c#?

  - by moon

  here is my code it shares the folder but that does not work correctly when i want to access it , it shows access denied help required, private static void ShareFolder(string FolderPath, string ShareName, string Description) { try { // Create a ManagementClass object ManagementClass managementClass = new ManagementClass("Win32_Share"); // Create ManagementBaseObjects for in and out parameters ManagementBaseObject inParams = managementClass.GetMethodParameters("Create"); ManagementBaseObject outParams; // Set the input parameters inParams["Description"] = Description; inParams["Name"] = ShareName; inParams["Path"] = FolderPath; inParams["Type"] = 0x0; // Disk Drive //Another Type: //DISK_DRIVE = 0x0; //PRINT_QUEUE = 0x1; //DEVICE = 0x2; //IPC = 0x3; //DISK_DRIVE_ADMIN = 0x80000000; //PRINT_QUEUE_ADMIN = 0x80000001; //DEVICE_ADMIN = 0x80000002; //IPC_ADMIN = 0x8000003; //inParams["MaximumAllowed"] = int maxConnectionsNum; // Invoke the method on the ManagementClass object outParams = managementClass.InvokeMethod("Create", inParams, null); // Check to see if the method invocation was successful if ((uint)(outParams.Properties["ReturnValue"].Value) != 0) { throw new Exception("Unable to share directory. Because Directory is already shared or directory not exist"); }//end if }//end try catch (Exception ex) { MessageBox.Show(ex.Message, "error!"); }//end catch }//End Method

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• why is a minus sign prepended to my biginteger?

  - by kyrogue

  package ewa; import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.logging.Level; import java.util.logging.Logger; import java.math.BigInteger; /** * * @author Lotus */ public class md5Hash { public static void main(String[] args) throws NoSuchAlgorithmException { String test = "abc"; MessageDigest md = MessageDigest.getInstance("MD5"); try { md.update(test.getBytes("UTF-8")); byte[] result = md.digest(); BigInteger bi = new BigInteger(result); String hex = bi.toString(16); System.out.println("Pringting result"); System.out.println(hex); } catch (UnsupportedEncodingException ex) { Logger.getLogger(md5Hash.class.getName()).log(Level.SEVERE, null, ex); } } } i am testing conversion of byte to hex and when done, the end result has a minus sign on the beginning of the string, why does this happen? i have read the docs and it says it will add a minus sign, however i do not understand it. And will the minus sign affect the hash result? because i am going to implement it to hash password stored on my database

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• Multiple generic parameters on a html helper extension method

  - by WestDiscGolf

  What I'm trying to do is create an extension method for the HtmlHelper to create a specific output and associated details like TextBoxFor<. What I want to do is specify the property from the model class as per TextBoxFor<, then an associated controller action and other parameters. So far the signature of the method looks like: public static MvcHtmlString Create<TModel, TProperty, TController>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, Expression<Action<TController>> action, object htmlAttributes) where TController : Controller where TModel : class The issue occurs when I go to call it. In my view if I call it as per the TextBoxFor without specifying the Model type I am able to specify the lambda expression to set the property which it's for, but when I go to specify the action I am unable to. However, when I specify the controller type Html.Create<HomeController>( ... ) I am unable to specify the model property that the control is to be created for. I want to be able to call it like <%= Html.Create(x => x.Title, controller => controller.action, null) %> I've been hitting my head for a few hours now on this issue over the past day, can anyone point me in the right direction?

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• What if a large number of objects are passed to my SwingWorker.process() method?

  - by Trejkaz

  I just found an interesting situation. Suppose you have some SwingWorker (I've made this one vaguely reminiscent of my own): public class AddressTreeBuildingWorker extends SwingWorker<Void, NodePair> { private DefaultTreeModel model; public AddressTreeBuildingWorker(DefaultTreeModel model) { } @Override protected Void doInBackground() { // Omitted; performs variable processing to build a tree of address nodes. } @Override protected void process(List<NodePair> chunks) { for (NodePair pair : chunks) { // Actually the real thing inserts in order. model.insertNodeInto(parent, child, parent.getChildCount()); } } private static class NodePair { private final DefaultMutableTreeNode parent; private final DefaultMutableTreeNode child; private NodePair(DefaultMutableTreeNode parent, DefaultMutableTreeNode child) { this.parent = parent; this.child = child; } } } If the work done in the background is significant then things work well - process() is called with relatively small lists of objects and everything is happy. Problem is, if the work done in the background is suddenly insignificant for whatever reason, process() receives a huge list of objects (I have seen 1,000,000, for instance) and by the time you process each object, you have spent 20 seconds on the Event Dispatch Thread, exactly what SwingWorker was designed to avoid. In case it isn't clear, both of these occur on the same SwingWorker class for me - it depends on the input data, and the type of processing the caller wanted. Is there a proper way to handle this? Obviously I can intentionally delay or yield the background processing thread so that a smaller number might arrive each time, but this doesn't feel like the right solution to me.

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• ASP.NET MVC 2.0 + Implementation of a IRouteHandler goes not fire

  - by Peter

  Can anybody please help me with this as I have no idea why public IHttpHandler GetHttpHandler(RequestContext requestContext) is not executing. In my Global.asax.cs I have public class MvcApplication : System.Web.HttpApplication { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL with parameters new { controller = "Home", action = "Index", id = "" } // Parameter defaults ); routes.Add("ImageRoutes", new Route("Images/{filename}", new CustomRouteHandler())); } protected void Application_Start() { RegisterRoutes(RouteTable.Routes); } } //CustomRouteHandler implementation is below public class CustomRouteHandler : IRouteHandler { public IHttpHandler GetHttpHandler(RequestContext requestContext) { // IF I SET A BREAK POINT HERE IT DOES NOT HIT FOR SOME REASON. string filename = requestContext.RouteData.Values["filename"] as string; if (string.IsNullOrEmpty(filename)) { // return a 404 HttpHandler here } else { requestContext.HttpContext.Response.Clear(); requestContext.HttpContext.Response.ContentType = GetContentType(requestContext.HttpContext.Request.Url.ToString()); // find physical path to image here. string filepath = requestContext.HttpContext.Server.MapPath("~/logo.jpg"); requestContext.HttpContext.Response.WriteFile(filepath); requestContext.HttpContext.Response.End(); } return null; } } Can any body tell me what I'm missing here. Simply public IHttpHandler GetHttpHandler(RequestContext requestContext) does not fire. I havn't change anything in the web.config either. What I'm missing here? Please help.

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• What is the space character for the browser?

  - by Hiro Protagonist

  echo "\n\s\s\s\s\s\s" . "<div id='data-load' data-load='" . $load . "'></div>"; \n works for adding a return in...I tried \s logically for space but this does not work. Keep mind, I don't want this rendered in the browser view...but in the source view ( when you click view-source )...I'm trying to put my html in to a readable form. echo "&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp\n" . "<div id='data-path' data-path='" . $path . "'></div>"; This does not work either. I am composing HTML from PHP... echo " \n" . "<div id='data-load' data-load='" . $load . "'></div>"; This does not work either. Actual Code: public static function setUniversals() { $shared_object = new Shared(); if ( $shared_object->getLoadOn() == 1 ) { $load = 'server'; } else { $load = 'client'; } if( getcwd() === '/home/foo/public_html/develop' ) { $path = 'development'; } else { $path = 'production'; } $shared_object = new Shared(); echo "\n"; echo "\n " . "<div id='data-path' data-path='" . $path . "'></div>"; echo "\n " . "<div id='data-load' data-load='" . $load . "'></div>"; }

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• Amazone API ItemSearch returns (400) Bad Request.

  - by BuzzBubba

  I'm using a simple example from Amazon documentation for ItemSearch and I get a strange error: "The remote server returned an unexpected response: (400) Bad Request." This is the code: public static void Main() { //Remember to create an instance of the amazon service, including you Access ID. AWSECommerceServicePortTypeClient service = new AWSECommerceServicePortTypeClient(new BasicHttpBinding(), new EndpointAddress( "http://webservices.amazon.com/onca/soap?Service=AWSECommerceService")); AWSECommerceServicePortTypeClient client = new AWSECommerceServicePortTypeClient( new BasicHttpBinding(), new EndpointAddress("http://webservices.amazon.com/onca/soap?Service=AWSECommerceService")); // prepare an ItemSearch request ItemSearchRequest request = new ItemSearchRequest(); request.SearchIndex = "Books"; request.Title = "Harry+Potter"; request.ResponseGroup = new string[] { "Small" }; ItemSearch itemSearch = new ItemSearch(); itemSearch.Request = new ItemSearchRequest[] { request }; itemSearch.AWSAccessKeyId = accessKeyId; // issue the ItemSearch request try { ItemSearchResponse response = client.ItemSearch(itemSearch); // write out the results foreach (var item in response.Items[0].Item) { Console.WriteLine(item.ItemAttributes.Title); } } catch(Exception e) { Console.ForegroundColor = ConsoleColor.Red; Console.WriteLine(e.Message); Console.ForegroundColor = ConsoleColor.White; Console.WriteLine("Press any key to quit..."); Clipboard.SetText(e.Message); } Console.ReadKey(); What is wrong?

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• Print an array elements

  - by 1ace1

  Hello guys, this is my first post and im still a beginner in the programming world so bare with me. I just created an array with 100 initialized values and i want to print out 10 elements on each line so it would be somthing like this 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ...26 this is the code i used and i managed to do it for the first 10 elements but i couldnt figure out how to do it for the rest public static void main(String[] args) { int[] numbers = { 0,1,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17}; int i, count = 0; for (i = 0; i < numbers.length; i++) { System.out.print(numbers[i] + " "); count++; if (count == 9) for (i = 9; i < numbers.length; i++) System.out.println(numbers[i] + " "); } } thanks!

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• make a thread which recieves values from other threads

  - by farteaga88

  This program in Java creates a list of 15 numbers and creates 3 threads to search for the maximum in a given interval. I want to create another thread that takes those 3 numbers and get the maximum. but i don't know how to get those values in the other thread. public class apple implements Runnable{ String name; int time, number, first, last, maximum; int[] array = {12, 32, 54 ,64, 656, 756, 765 ,43, 34, 54,5 ,45 ,6 , 5, 65}; public apple(String s, int f, int l){ name = s; first = f; last = l; maximum = array[0]; } public void run(){ try{ for(int i = first; i < last; i++ ) { if(maximum < array[i]) { maximum = array[i]; } } System.out.println("Thread"+ name + "maximum = " + maximum); }catch(Exception e){} } public static void main(String[] args){ Thread t1 = new Thread(new apple("1 ", 0, 5)); Thread t2 = new Thread(new apple("2 ", 5, 10 )); Thread t3 = new Thread(new apple("3 ", 10, 15)); try{ t1.start(); t2.start(); t3.start(); }catch(Exception e){} } }

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• Comparing all properties of an object using expression trees

  - by stringargs

  Hi, I'm trying to write a simple generator that uses an expression tree to dynamically generate a method that compares all properties of an instance of a type to the properties of another instance of that type. This works fine for most properties, like int an string, but fails for DateTime? (and presumably other nullable value types). The method: static Delegate GenerateComparer(Type type) { var left = Expression.Parameter(type, "left"); var right = Expression.Parameter(type, "right"); Expression result = null; foreach (var p in type.GetProperties()) { var leftProperty = Expression.Property(left, p.Name); var rightProperty = Expression.Property(right, p.Name); var equals = p.PropertyType.GetMethod("Equals", new[] { p.PropertyType }); var callEqualsOnLeft = Expression.Call(leftProperty, equals, rightProperty); result = result != null ? (Expression)Expression.And(result, callEqualsOnLeft) : (Expression)callEqualsOnLeft; } var method = Expression.Lambda(result, left, right).Compile(); return method; } On a DateTime? property it fails with: Expression of type 'System.Nullable`1[System.DateTime]' cannot be used for parameter of type 'System.Object' of method 'Boolean Equals(System.Object)' OK, so it finds an overload of Equals that expects object. So why can't I pass a DateTime? into that, as it's convertible to object? If I look at Nullable<T>, it indeed has an override of Equals(object o). PS: I realize that this isn't a proper generator yet as it can't deal with null values, but I'll get to that :)

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