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  • EGODatabase does not retain inserted record

    - by user135775
    Hi Guy! I'm using EGODatabase to process my data. When I tried to insert data into the database which I created with Base and attached to the project, the data that was inserted programmatically will not show up when I restart my app.However the data inserted manually using Base will show up just fine. Following is the code for inserting data into the database: NSString *path = [[NSBundle mainBundle] pathForResource:@"Database" ofType:@"db"]; db = [EGODatabase databaseWithPath:path]; if ([db open]) { NSLog(@"Database is opened successfully!"); } else { NSLog(@"Database is failed to open!"); } NSArray *params = [NSArray arrayWithObjects:[aFeed feedID], [aFeed title], nil]; [db executeUpdate:@"Insert INTO Feed (FeedID, Title) VALUES (?, ?)" parameters:params]; EGODatabaseResult *results = [db executeQuery:@"SELECT * FROM Feed"]; for ( EGODatabaseRow * row in results) { NSLog(@"ID: %@ Title: %@", [row stringForColumn:@"FeedID"], [row stringForColumn:@"Title"]); } I appreciate if anyone can share me a working sample code for EGODatabase. I'm using EGODatabase because I might have multi-threading code that write to the database. Thank in advance.

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  • Is this use of PreparedStatements in a Thread in JAVA correct?

    - by Gormcito
    I'm still an undergrad just working part time and so I'm always trying to be aware of better ways to do things. Recently I had to write a program for work where the main thread of the program would spawn "task" threads (for each db "task" record) which would perform some operations and then update the record to say that it has finished. Therefore I needed a database connection object and PreparedStatement objects in or available to the ThreadedTask objects. This is roughly what I ended up writing, is creating a PreparedStatement object per thread a waste? I thought static PreparedStatments could create race conditions... Thread A stmt.setInt(); Thread B stmt.setInt(); Thread A stmt.execute(); Thread B stmt.execute(); A´s version never gets execed.. Is this thread safe? Is creating and destroying PreparedStatement objects that are always the same not a huge waste? public class ThreadedTask implements runnable { private final PreparedStatement taskCompleteStmt; public ThreadedTask() { //... taskCompleteStmt = Main.db.prepareStatement(...); } public run() { //... taskCompleteStmt.executeUpdate(); } } public class Main { public static final db = DriverManager.getConnection(...); }

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  • STI and accepts_nested_attributes_for in rails

    - by ryanshackintosh
    I have models as follows: class Entity < ActiveRecord::Base has_many :addresses accepts_nested_attributes_for :addresses, :reject_if => lambda { |a| a[:label].blank?} , :allow_destroy => true end class Client < Entity before_save :set_type private def set_type self.type = "Client" end end class Address < ActiveRecord::Base belongs_to :entity end I have recently implemented accepts_nested_attributes_for on the /clients/new form, as follows: <% form_for(@client, :html => {:class => 'form'}) do |f| -%> <%= f.label :name %> <%= f.text_field :name -%> <%= f.label :phone %> <%= f.text_field :phone %> <% f.fields_for :addresses do |a| %> <%= a.label :street %> <%= a.text_field :street%> <%= a.label :city %> <%= a.text_field :city %> <% end %> <% end %> And my controller as follows: class ClientsController < ApplicationController before_filter :load_client , :except => [:index, :new, :create, :render_clients] def new @client = Client.new @client.addresses.build end def create @client = Client.new(params[:client]) if @client.save flash[:notice] = 'Client has been successfully added' redirect_to @client else render :action => 'new' end end The issue is that when the record is saved it gives an error stating: "Entity can't be blank" I assume it is something to do with the fact that a 'Client' and not an 'Entity' is being added. Can anyone point me in the right direction?

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  • in haskell, why do I need to specify type constraints, why can't the compiler figure them out?

    - by Steve
    Consider the function, add a b = a + b This works: *Main> add 1 2 3 However, if I add a type signature specifying that I want to add things of the same type: add :: a -> a -> a add a b = a + b I get an error: test.hs:3:10: Could not deduce (Num a) from the context () arising from a use of `+' at test.hs:3:10-14 Possible fix: add (Num a) to the context of the type signature for `add' In the expression: a + b In the definition of `add': add a b = a + b So GHC clearly can deduce that I need the Num type constraint, since it just told me: add :: Num a => a -> a -> a add a b = a + b Works. Why does GHC require me to add the type constraint? If I'm doing generic programming, why can't it just work for anything that knows how to use the + operator? In C++ template programming, you can do this easily: #include <string> #include <cstdio> using namespace std; template<typename T> T add(T a, T b) { return a + b; } int main() { printf("%d, %f, %s\n", add(1, 2), add(1.0, 3.4), add(string("foo"), string("bar")).c_str()); return 0; } The compiler figures out the types of the arguments to add and generates a version of the function for that type. There seems to be a fundamental difference in Haskell's approach, can you describe it, and discuss the trade-offs? It seems to me like it would be resolved if GHC simply filled in the type constraint for me, since it obviously decided it was needed. Still, why the type constraint at all? Why not just compile successfully as long as the function is only used in a valid context where the arguments are in Num? Thank you.

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  • How to override part of an overload function in JavaScript

    - by Guan Yuxin
    I create a class with a function like this var Obj=function(){this.children=[];this.parent=null;}//a base class Obj.prototype.index=function(child){ // the index of current obj if(arguments.length==0){ return this.parent?this.parent.index(this):0; } // the index of a child matchs specific obj [to be override] return -1; } basically it is just an overload function composed of index() and index(child). Then I create a sub class,SubObj or whatever, inherits from Obj SubObj.prototype.prototype=Obj; Now, it's time to override the index(child) function,however, index() is also in the function an I don't want to overwrite it too. One solution is to write like this var Obj=function(){this.children=[];this.parent=null;}//a base class Obj.prototype.index=function(child){ // the index of current obj if(arguments.length==0){ return this.parent?this.parent.index(this):0; } // the index of a child matchs specific obj [to be override] return this._index(this); } Obj.prototype._index=function(this){ return -1; } SubObj.prototype._index=function(this){/* overwriteing */} But this will easily mislead other coders as _index(child) should be both private(should not be used except index() function) and public(is an overload function of index(),which is public) you guys have better idea?

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  • C++ IDE for Linux?

    - by Sven
    I want to expand my programming horizons to Linux. A good, dependable basic toolset is important, and what is more basic than an IDE? I could find these SO topics: Lightweight IDE for linux and What tools do you use to develop C++ applications on Linux? I'm not looking for a lightweight IDE. If an IDE is worth the money, then I will pay for it, so it need not be free. My question, then: What good, C++ programming IDE is available for Linux? The minimums are fairly standard: syntax highlighting, code completion (like intellisense or its Eclipse counterpart) and integrated debugging (e.g., basic breakpoints). I have searched for it myself, but there are so many that it is almost impossible to separate the good from the bads by hand, especially for someone like me who has little C++ coding experience in Linux. I know that Eclipse supports C++, and I really like that IDE for Java, but is it any good for C++ and is there something better? The second post actually has some good suggestions, but what I am missing is what exactly makes the sugested IDE so good for the user, what are its (dis)advantages? Maybe my question should therefore be: What IDE do you propose (given your experiences), and why?

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  • Can it be important to call remove() on an EJB 3 stateless session bean? Perhaps on weblogic?

    - by Michael Borgwardt
    I'm in the process of migrating an EJB 2 application to EJB 3 (and what a satisfying task it is to delete all those deployment descriptors!). It used to run on Weblogic and now runs on Glassfish. The task is going very smoothly, but one thing makes me wary: The current code takes great care to ensure that EJBObject.remove() is called on the bean when it's done its job, and other developers have (unfortunately very vague) memories of "bad things" happening when that was not done. However, with EJB3, the implementation class does not implement EJBObject, so there is no remove() method to be called. And my understanding is that there isn't really any point at all in calling it on stateless session beans, since they are, well, stateless. Could these "bad things" have been weblogic-specific? If not, what else? Should I avoid the full EJB3 lightweightness and keep a remote interface that extends EJBObject? Or just write it off as cargo-cult programming and delete all those try/finally clauses? I'm leaning towards the latter, but now feeling very comfortable with it.

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  • Ways to make (relatively) safe assumptions about the type of concrete subclasses?

    - by Kylotan
    I have an interface (defined as a abstract base class) that looks like this: class AbstractInterface { public: bool IsRelatedTo(const AbstractInterface& other) const = 0; } And I have an implementation of this (constructors etc omitted): class ConcreteThing { public: bool IsRelatedTo(const AbstractInterface& other) const { return m_ImplObject.has_relationship_to(other.m_ImplObject); } private: ImplementationObject m_ImplObject; } The AbstractInterface forms an interface in Project A, and the ConcreteThing lives in Project B as an implementation of that interface. This is so that code in Project A can access data from Project B without having a direct dependency on it - Project B just has to implement the correct interface. Obviously the line in the body of the IsRelatedTo function cannot compile - that instance of ConcreteThing has an m_ImplObject member, but it can't assume that all AbstractInterfaces do, including the other argument. In my system, I can actually assume that all implementations of AbstractInterface are instances of ConcreteThing (or subclasses thereof), but I'd prefer not to be casting the object to the concrete type in order to get at the private member, or encoding that assumption in a way that will crash without a diagnostic later if this assumption ceases to hold true. I cannot modify ImplementationObject, but I can modify AbstractInterface and ConcreteThing. I also cannot use the standard RTTI mechanism for checking a type prior to casting, or use dynamic_cast for a similar purpose. I have a feeling that I might be able to overload IsRelatedTo with a ConcreteThing argument, but I'm not sure how to call it via the base IsRelatedTo(AbstractInterface) method. It wouldn't get called automatically as it's not a strict reimplementation of that method. Is there a pattern for doing what I want here, allowing me to implement the IsRelatedTo function via ImplementationObject::has_relationship_to(ImplementationObject), without risky casts? (Also, I couldn't think of a good question title - please change it if you have a better one.)

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  • Using parameterized function calls in SELECT statements. MS SQL Server

    - by geekzlla
    I have taken over some code from a previous developer and have come across this SQL statement that calls several SQL functions. As you can see, the function calls in the select statement pass a parameter to the function. How does the SQL statement know what value to replace the variable with? For the below sample, how does the query engine know what to replace nDeptID with when it calls, fn_SelDeptName_DeptID(nDeptID)? nDeptID IS a column in table Note. SELECT STATEMENT: SELECT nCustomerID AS [Customer ID], nJobID AS [Job ID], dbo.fn_SelDeptName_DeptID(nDeptID) AS Department, nJobTaskID AS JobTaskID, dbo.fn_SelDeptTaskDesc_OpenTask(nJobID, nJobTaskID) AS Task, nStandardNoteID AS StandardNoteID, dbo.fn_SelNoteTypeDesc(nNoteID) AS [Note Type], dbo.fn_SelGPAStandardNote(nStandardNoteID) AS [Standard Note], nEntryDate AS [Entry Date], nUserName as [Added By], nType AS Type, nNote AS Note FROM Note WHERE nJobID = 844261 xORDER BY nJobID, Task, [Entry Date] ====================== Function fn_SelDeptName_DeptID: ALTER FUNCTION [dbo].[fn_SelDeptName_DeptID] (@iDeptID int) RETURNS varchar(25) -- Used by DataCollection for Job Tracking -- if the Deptartment isnt found return an empty string BEGIN -- Return the Department name for the given DeptID. DECLARE @strDeptName varchar(25) IF @iDeptID = 0 SET @strDeptName = '' ELSE BEGIN SET @strDeptName = (SELECT dName FROM Department WHERE dDeptID = @iDeptID) IF (@strDeptName IS NULL) SET @strDeptName = '' END RETURN @strDeptName END ========================== Thanks in advance.

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  • Is it good practise to blank out inherited functionality that will not be used?

    - by Timo Kosig
    I'm wondering if I should change the software architecture of one of my projects. I'm developing software for a project where two sides (in fact a host and a device) use shared code. That helps because shared data, e.g. enums can be stored in one central place. I'm working with what we call a "channel" to transfer data between device and host. Each channel has to be implemented on device and host side. We have different kinds of channels, ordinary ones and special channels which transfer measurement data. My current solution has the shared code in an abstract base class. From there on code is split between the two sides. As it has turned out there are a few cases when we would have shared code but we can't share it, we have to implement it on each side. The principle of DRY (don't repeat yourself) says that you shouldn't have code twice. My thought was now to concatenate the functionality of e.g. the abstract measurement channel on the device side and the host side in an abstract class with shared code. That means though that once we create an actual class for either the device or the host side for that channel we have to hide the functionality that is used by the other side. Is this an acceptable thing to do: public abstract class MeasurementChannelAbstract { protected void MethodUsedByDeviceSide() { } protected void MethodUsedByHostSide() { } } public class DeviceMeasurementChannel : MeasurementChannelAbstract { public new void MethodUsedByDeviceSide() { base.MethodUsedByDeviceSide(); } } Now, DeviceMeasurementChannel is only using the functionality for the device side from MeasurementChannelAbstract. By declaring all methods/members of MeasurementChannelAbstract protected you have to use the new keyword to enable that functionality to be accessed from the outside. Is that acceptable or are there any pitfalls, caveats, etc. that could arise later when using the code?

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  • Can you explain this generics behavior and if I have a workaround?

    - by insta
    Sample program below: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace GenericsTest { class Program { static void Main(string[] args) { IRetrievable<int, User> repo = new FakeRepository(); Console.WriteLine(repo.Retrieve(35)); } } class User { public int Id { get; set; } public string Name { get; set; } } class FakeRepository : BaseRepository<User>, ICreatable<User>, IDeletable<User>, IRetrievable<int, User> { // why do I have to implement this here, instead of letting the // TKey generics implementation in the baseclass handle it? //public User Retrieve(int input) //{ // throw new NotImplementedException(); //} } class BaseRepository<TPoco> where TPoco : class,new() { public virtual TPoco Create() { return new TPoco(); } public virtual bool Delete(TPoco item) { return true; } public virtual TPoco Retrieve<TKey>(TKey input) { return null; } } interface ICreatable<TPoco> { TPoco Create(); } interface IDeletable<TPoco> { bool Delete(TPoco item); } interface IRetrievable<TKey, TPoco> { TPoco Retrieve(TKey input); } } This sample program represents the interfaces my actual program uses, and demonstrates the problem I'm having (commented out in FakeRepository). I would like for this method call to be generically handled by the base class (which in my real example is able to handle 95% of the cases given to it), allowing for overrides in the child classes by specifying the type of TKey explicitly. It doesn't seem to matter what parameter constraints I use for the IRetrievable, I can never get the method call to fall through to the base class. Also, if anyone can see an alternate way to implement this kind of behavior and get the result I'm ultimately looking for, I would be very interested to see it. Thoughts?

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  • Coding the R-ight way - avoiding the for loop

    - by mropa
    I am going through one of my .R files and by cleaning it up a little bit I am trying to get more familiar with writing the code the r-ight way. As a beginner, one of my favorite starting points is to get rid of the for() loops and try to transform the expression into a functional programming form. So here is the scenario: I am assembling a bunch of data.frames into a list for later usage. dataList <- list (dataA, dataB, dataC, dataD, dataE ) Now I like to take a look at each data.frame's column names and substitute certain character strings. Eg I like to substitute each "foo" and "bar" with "baz". At the moment I am getting the job done with a for() loop which looks a bit awkward. colnames(dataList[[1]]) [1] "foo" "code" "lp15" "bar" "lh15" colnames(dataList[[2]]) [1] "a" "code" "lp50" "ls50" "foo" matchVec <- c("foo", "bar") for (i in seq(dataList)) { for (j in seq(matchVec)) { colnames (dataList[[i]])[grep(pattern=matchVec[j], x=colnames (dataList[[i]]))] <- c("baz") } } Since I am working here with a list I thought about the lapply function. My attempts handling the job with the lapply function all seem to look alright but only at first sight. If I write f <- function(i, xList) { gsub(pattern=c("foo"), replacement=c("baz"), x=colnames(xList[[i]])) } lapply(seq(dataList), f, xList=dataList) the last line prints out almost what I am looking for. However, if i take another look at the actual names of the data.frames in dataList: lapply (dataList, colnames) I see that no changes have been made to the initial character strings. So how can I rewrite the for() loop and transform it into a functional programming form? And how do I substitute both strings, "foo" and "bar", in an efficient way? Since the gsub() function takes as its pattern argument only a character vector of length one.

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  • Use of Java [Interfaces / Abstract classes]

    - by Samuel
    Hello, Lately i decided to take a look at Java so i am still pretty new to it and also to the approach of OO programming, so i wanted to get some things straight before learning more, (i guess it's never to soon to start with good practices). I am programming a little 2D game for now but i think my question applies to any non trivial project. For the simplicity i'll provide examples from my game. I have different kinds of zombies, but they all have the same attributes (x, y, health, attack etc) so i wrote an interface Zombie which i implement by WalkingZombie, RunningZombie TeleportingZombie etc. Is this the best thing to do? Am i better of with an abstract class? Or with a super class? (I am not planning to partially implement functions - therefor my choice for an interface instead of an abstract class) I have one class describing the main character (Survivor) and since it is pretty big i wanted to write an interface with the different functions, so that i can easily see and share the structure of it. Is it good practice? Or is it simply a waste of space and time? I hope this question will not be rated as subjective because i thought that experienced programmers won't disagree about this kind of topic since the use of interfaces / super classes / abstract classes follows logical rules and is thereby not simply a personal choice. Thank you for your time -Samuel

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  • Shared Git repo syncing to svn causing git svn rebase to pollute repo with a log of no-op merge prob

    - by John K
    This wasn't so bad at the beginning, but now I have hundreds of no-op merge problems (solved by git rebase --skip). I have setup a shared git repo for my group because it is easier to deal with. But the company uses SVN so I have to keep SVN in sync with GIT. Worked like a dream at first, but after weeks of doing this GIT is giving me a lot of the following errors. Applying: * making all config actions work Using index info to reconstruct a base tree... Falling back to patching base and 3-way merge... Auto-merging app/controllers/vulnerabilities_controller.rb CONFLICT (content): Merge conflict in app/controllers/vulnerabilities_controller.rb Auto-merging public/javascripts/network_analysis_vulnerability_config.js CONFLICT (content): Merge conflict in public/javascripts/network_analysis_vulnerability_config.js Failed to merge in the changes. Patch failed at 0046 * making all config actions work My workflow: git co master git pull origin git svn rebase ... deal with no-op merge problems ... git svn dcommit git pull origin git push origin The problem is that what is in SVN is the correct so I use git rebase --skip, but I have to do that hundreds of times before I can dcommit. How do I clear these merge problems permanently?

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  • Problem in homemade function to merge objects

    - by Eric
    I'm trying to make a function that merges arrays. The reason is, I have a function that supposed to get the settings of an entity, and merge them with the global defaults. //So for example, let's say globalOptions is something like this var globalOptions={opt1:'foo',opt2:'something'}; //and this is entityOptions var entityOptions={opt1:'foofoo',opt2:null}; The only difference is it has objects in objects and objects in objects in objects, so what I made was a function that loops through all objects, thinking I would later, easily be able to loop through it all. Please ignore the array thing. That is defected, but unneeded. function loopObj(obj, call, where, objcall, array) { if ($.isArray(obj) || $.isPlainObject(obj)) { for (i in obj) { if ($.isArray(obj)) { if (array) { loopObj(obj[i], call, where[where.length] = i, true); if (objcall) { call(obj[i],where,true); } } else { loopObj(obj[i], call, where+'['+i+']', false); if (objcall) { call(obj[i],where,true); } } } else { if (array) { loopObj(obj[i], call, where[where.length] = parseInt(i), true); if (objcall) { call(obj[i],where,true); } } else { loopObj(obj[i], call, where+'[\''+i+'\']', false); if (objcall) { call(obj[i],where,true); } } } } } else { return call(obj,where); } } Then I made this program to convert it: function mergeObj(a,b) { temp.retd = new Object(); loopObj(a,function (c,d) { if (c) { eval(d.replace('%par%','temp.retd'))=c; } else { eval(d.replace('%par%','temp.retd'))=eval(d.replace('%par%','b')); } },'%par%', true); return temp.retd(); } I get the error: Uncaught ReferenceError: Invalid left-hand side in assignment (anonymous function)base.js:51 loopObjbase.js:40 loopObjbase.js:31 mergeObjbase.js:46 (anonymous function)base.js:72 I know what it means, the eval returns an anonomys variable (copy of the variable), so I can't set it, only get it.

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  • How to update attributes without validation

    - by Brian Roisentul
    I've got a model with its validations, and I found out that I can't update an attribute without validating the object before. I already tried to add on => :create syntax at the end of each validation line, but I got the same results. My announcement model have the following validations: validates_presence_of :title validates_presence_of :description validates_presence_of :announcement_type_id validate :validates_publication_date validate :validates_start_date validate :validates_start_end_dates validate :validates_category validate :validates_province validates_length_of :title, :in => 6..255, :on => :save validates_length_of :subtitle, :in => 0..255, :on => :save validates_length_of :subtitle, :in => 0..255, :on => :save validates_length_of :place, :in => 0..50, :on => :save validates_numericality_of :vacants, :greater_than_or_equal_to => 0, :only_integer => true validates_numericality_of :price, :greater_than_or_equal_to => 0, :only_integer => true My rake task does the following: task :announcements_expiration => :environment do announcements = Announcement.expired announcements.each do |a| #Gets the user that owns the announcement user = User.find(a.user_id) puts a.title + '...' a.state = 'deactivated' if a.update_attributes(:state => a.state) puts 'state changed to deactivated' else a.errors.each do |e| puts e end end end This throws all the validation exceptions for that model, in the output. Does anybody how to update an attribute without validating the model?

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  • Problem with Java FX Look and Feel

    - by drachenfels
    Hi, I was looking at some of the examples from the Deitel and Deitel's book for Programming in Java, and one of the first examples is a very simple Swing display. Hence this snippet of code : import javax.swing.*; public class cdea { public static void main(String args[]){ JOptionPane.showMessageDialog(null,"\"Welcome to Java Programming!\""); System.exit(0); //end method main } } I read some stuff regarding how one can get native UI look and feel by using UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName()); to the program. However, when I just add this to my main method, it gives me a host of errors. Specifically : Multiple markers at this line - Unhandled exception type IllegalAccessException - Unhandled exception type InstantiationException - Unhandled exception type ClassNotFoundException - Unhandled exception type UnsupportedLookAndFeelException However when I use it as part of a try/catch exception loop (is that what it is called?) as detailed on http://stackoverflow.com/questions/1590863/getting-java-applications-to-look-native-on-windows-how , I get the program running properly. Could anyone tell me in simple language why this is so? As in, why can't I directly get the System look and feel; why do I have to use it with exception handling? I'm new to Java, and OOP in general, so I'm sorry if I'm being too simplistic.

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  • NHibernate Entity code conversion from #C to VB.Net

    - by CoderRoller
    Hello and thanks for your help in advance. I am starting on the NHibernate world and i am experimenting with the NHibernate CookBook recipes, i am trying to set a base entity class for my entities and this is the C# code for this. I would like to know whats the VB.NET version so i can implement it in my sample project. This is the C# code: public abstract class Entity<TId> { public virtual TId Id { get; protected set; } public override bool Equals(object obj) { return Equals(obj as Entity<TId>); } private static bool IsTransient(Entity<TId> obj) { return obj != null && Equals(obj.Id, default(TId)); } private Type GetUnproxiedType() { return GetType(); } public virtual bool Equals(Entity<TId> other) { if (other == null) return false; if (ReferenceEquals(this, other)) return true; if (!IsTransient(this) && !IsTransient(other) && Equals(Id, other.Id)) { var otherType = other.GetUnproxiedType(); var thisType = GetUnproxiedType(); return thisType.IsAssignableFrom(otherType) || otherType.IsAssignableFrom(thisType); } return false; } public override int GetHashCode() { if (Equals(Id, default(TId))) return base.GetHashCode(); return Id.GetHashCode(); } } I tried using an online converter but puts a Nothing reference in place of default(TId) that doesn't seem right to me that's why I request for help: Private Shared Function IsTransient(obj As Entity(Of TId)) As Boolean Return obj IsNot Nothing AndAlso Equals(obj.Id, Nothing) End Function I Would appreciate the insight you may give me on the subject.

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  • is there a Java GUI for dummies ?

    - by MHero
    Hello, first I want to apologize about my english, it may be not clear enough. Well, I'm new to Java programming, and I search over this web about use of Swing, AWT, 2D, etc. but I didn't get the answer I was looking for. I want to know about a book or method to learn Java GUI programming (not even sure this is a propper term). Previous answers guide me to Filthy Rich Clients by Romain Guy and also to The Swing Tutorial in Sun Web Page. and No offense, but...the first one seems too complex and the second one a bit disorganize. so I ask about a more "for dummies" method. Thanks EDIT: Thanks everyboy, you're very kind and serious. I want to clear some things that I didn't state for being my first question. I dont' want to use autogenerated code(Don't want to say why only focus on my question for consistency) Also I've read Deitel & Deitel and it's a good beginners book but it seems to me that doesn't cover layout(and other details) Finally, I tried to read netbeans generated code but it's a mess find method by method and function by function the way that the IDE does it I hope this edition helps to solve my question

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  • Limiting a search to records from last_request_at...

    - by bgadoci
    I am trying to figure out how to display a count for records that have been created in a table since the last_request_at of a user. In my view I am counting the notes of a question with the following code: <% unless @questions.empty? %> <% @questions.each do |question| %> <%= h(question.notes.count) %> end end This is happening in the /views/users/show.html.erb file. Instead of counting all the notes for the question, I would only like to count the notes that have been created since the users last_request_at datetime. I don't neccessarily want to scope notes to display this 'new notes' count application wide, just simply in this one instance. To accomplish I am assuming I need to create a variable in the User#show action and call it in the view but not really sure how to do that. Other information you may need: class Note < ActiveRecord::Base belongs_to :user belongs_to :question end class Question < ActiveRecord::Base has_many :notes, :dependent => :destroy belongs_to :user end

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  • What happens when you create an instance of an object containing no state in C#?

    - by liquorice
    I am I think ok at algorithmic programming, if that is the right term? I used to play with turbo pascal and 8086 assembly language back in the 1980s as a hobby. But only very small projects and I haven't really done any programming in the 20ish years since then. So I am struggling for understanding like a drowning swimmer. So maybe this is a very niave question or I'm just making no sense at all, but say I have an object kind of like this: class Something : IDoer { void Do(ISomethingElse x) { x.DoWhatEverYouWant(42); } } And then I do var Thing1 = new Something(); var Thing2 = new Something(); Thing1.Do(blah); Thing2.Do(blah); does Thing1 = Thing2? does "new Something()" create anything? Or is it not much different different from having a static class, except I can pass it around and swap it out etc. Is the "Do" procedure in the same location in memory for both the Thing1(blah) and Thing2(blah) objects? I mean when executing it, does it mean there are two Something.Do procedures or just one?

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  • Rails how to return a list of answers with a specific question_id

    - by mytwocentsisworthtwocents
    Let's say I have two Models, Answers and Questions (there are others, but irrelevant to the question). The models are as follows: Answer.rb class Answer < ActiveRecord::Base attr_accessible :description, :question_id has_one :question, :through => :user, :dependent => :destroy validates :description, :presence => true end Question.rb class Question < ActiveRecord::Base attr_accessible :budget, :description, :headline, :user_id, :updated_at, :created_at belongs_to :user has_many :answers validates :headline, :description, :user_id, :presence => true end I'd like to display on a page a list of all answers associated with a question, and only those questions. I got this far. I believe this variable finds all the questions in the database by the question_id (foreign key): @findanswers = Answer.all(params[:question_id]) And this one grabs the the id of the current question (this code will reside as an ERB on the page where the current question is located): @questionshow = Question.find(params[:id]) And now I'm stuck. How do I put the two together so that I list all the answers with the current question id?

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  • Sheet and thread memory problem

    - by Xident
    Hi Guys, recently I started a project which can export some precalculated Grafix/Audio to files, for after processing. All I was doing is to put a new Window (with progressindicator and an Abort Button) in my main xib and opened it using the following code: [NSApp beginSheet: REC_Sheet modalForWindow: MOTHER_WINDOW modalDelegate: self didEndSelector: nil contextInfo: nil]; NSModalSession session=[NSApp beginModalSessionForWindow:REC_Sheet]; RECISNOTDONE=YES; while (RECISNOTDONE) { if ([NSApp runModalSession:session]!=NSRunContinuesResponse) break; usleep(100); } [NSApp endModalSession:session]; A Background Thread (pthread) was started earlier, to actually perform the work and save all the targas/wave file. Which worked great, but after an amount of time, it turned out that the main thread was not responding anymore and my memory footprint raised unstoppable. I tried to debug it with Instruments, and saw a lot of CFHash etc stuff growing to infinity. By accident i clicked below the sheet, and temporary it helped, the main thread (AppKit ?) was releasing it's stuff, but just for a little time. I can't explain it to me, first of all I thought it was the access from my thread to the Progressbar to update the Progress (intervalled at 0,5sec), so I cut it out. But even if I'm not updating anything and did nothing with the Progressbar, my Application eat up all the Memory, because of not releasing it's "Main-Event" or whatsoever Stuff. Is there any possibility to "drain" this Main thread Memory stuff (Runloop / NSApp call?). And why the heck doesn't the Main thread respond anymore (after this simple task) ??? I don't have a clou anymore, please help ! Thanks in advance ! P.S. How do you guys implement "threaded long task" Stuff and updating your gui ???

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  • EUpdateError exception not recognized when raised in TDatasetProvider.OnUpdateError. Why?

    - by max
    When I re-throw a EUpdateError exception in the TDatasetProvider.OnUpdateError event, it is not recognized as EUpdateError exception in the catch block. It's only recognized as base Excption. try ... //calls the TDatasetPorvider.OnUpdateError event. myClientDataSet.ApplyUpdates(0); ... except on ex: EUpdateError do begin //never goes here //Evaluate ex.ErrorCode end; on ex: Exception do begin //always goes here //the expression (ex is EUpdateError) returns false; end; end; Hiere is the corresponding .OnUpdateError implementaion: procedure MyDataModule.MyDatasetProviderOnUpdateError(..;E: EUpdateError;...); beign //Here, the expression (E is EUpdateException) returns true; raise E; end; The exception is re-thrown, but as it seems the EUpdateError is transformed into a plain base Execption. Does anybody know, why the class type get lost? I would need that type in order to check the .ErrorCode to know what went wrong and to prepare the proper user message.

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  • Ruby on rails 2 level model

    - by jony17
    I need some help creating a very simple forum in a existing model. What I want in a Game page, have a mini forum, where is possible create some topics and some comments to this topics. In the beginning I'm only implement topics. This is the error I have: Mysql2::Error: Column 'user_id' cannot be null: INSERT INTO `topics` (`game_id`, `question`, `user_id`) VALUES (1, 'asd', NULL) This is my main model: game.rb class Game < ActiveRecord::Base attr_accessible :name validates :user_id, presence: true validates :name, presence: true, length: { maximum: 50 } belongs_to :user has_many :topics, dependent: :destroy end topic.rb class Topic < ActiveRecord::Base validates_presence_of :question validates_presence_of :game_id attr_accessible :question, :user_id validates :question, length: {maximum: 50}, allow_blank: false belongs_to :game belongs_to :user end topic_controller.rb def create @game = Game.find(params[:game_id]) @topic = @game.topics.create(params[:topic]) @topic.user_id = current_user.id respond_to do |format| if @topic.save format.html { redirect_to @game, notice: 'Topic was successfully created.' } else format.html { render action: "new" } end end end game/show.html.erb <h2>Topics</h2> <% @game.topics.each do |topic| %> <p> <b>Question:</b> <%= topic.question %> </p> <% end %> <h2>Add a topic:</h2> <%= form_for([@game, @game.topics.build]) do |f| %> <div class="field"> <%= f.label :question %><br /> <%= f.text_field :question %> </div> <div class="actions"> <%= f.submit %> </div> <% end %> Thanks ;)

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