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  • Why doesn't the conditional operator correctly allow the use of "null" for assignment to nullable ty

    - by Daniel Coffman
    This will not compile, stating "Type of conditional expression cannot be determined because there is no implicit conversion between 'System.DateTime' and ''" task.ActualEndDate = TextBoxActualEndDate.Text != "" ? DateTime.Parse(TextBoxActualEndDate.Text) : null; This works just fine if (TextBoxActualEndDate.Text != "") task.ActualEndDate = DateTime.Parse(TextBoxActualEndDate.Text); else task.ActualEndDate = null;

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  • YUI Calendar: Skinning and CSS

    - by dound
    I'm using YUI 2's calendar in YUI 3. I want to make a few minor changes to the default sam skin. What is the best way to do that? Also, how does it load Sam's skin CSS? I didn't manually include it (though it seems like I should so the user can download it in the one request I make to the combo loader for css?). This is how I'm loading the CSS and JS now: <head> ... <link rel="stylesheet" type="text/css" href="http://yui.yahooapis.com/combo?3.1.0/build/cssreset/reset.css&amp;3.1.0/build/cssfonts/fonts.css&amp;3.1.0/build/cssbase/base.css"/> ... </head> ... <!--and at the end of the body tag:--> <script type="text/javascript" src="http://yui.yahooapis.com/combo?3.1.1/build/yui/yui-min.js&amp;3.1.1/build/oop/oop-min.js&amp;3.1.1/build/event-custom/event-custom-base-min.js&amp;3.1.1/build/event/event-base-min.js&amp;3.1.1/build/json/json-parse-min.js&amp;3.1.1/build/querystring/querystring-stringify-simple-min.js&amp;3.1.1/build/io/io-base-min.js&amp;3.1.1/build/dom/dom-base-min.js&amp;3.1.1/build/dom/selector-native-min.js&amp;3.1.1/build/dom/selector-css2-min.js&amp;3.1.1/build/node/node-base-min.js&amp;3.1.1/build/node/node-style-min.js&amp;3.1.1/build/stylesheet/stylesheet-min.js&amp;2in3.1/2.8.0/build/yui2-calendar/yui2-calendar-min.js&amp;2in3.1/2.8.0/build/yui2-yahoo/yui2-yahoo-min.js&amp;2in3.1/2.8.0/build/yui2-dom/yui2-dom-min.js&amp;2in3.1/2.8.0/build/yui2-event/yui2-event-min.js"></script> <script type="text/javascript">//<![CDATA[ YUI().use('yui2-calendar', function(Y) { var YAHOO = Y.YUI2; var cal = new YAHOO.widget.Calendar("cal",{navigator:true,mindate:'1/1/2000'); cal.render(); // ... The main problem I'm having is that it seems to dynamically load the Sam's skin, so any CSS I specify in my stylesheet or in the <head> section seem to be overridden. I can modify the style by getting the nodes and using YUI's Node.setStyle() method, but this doesn't seem like the best way to do things. Note: The script does include more than I need for just YUI 2's calendar, but that's because I use YUI 3 for other things irrelevant to this question.

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  • RoR associations through or not through?

    - by showFocus
    I have four models that are related to one another, the way I have it setup at the moment is I have to select a county, region and country when entering a new city. class Country < ActiveRecord::Base has_many :regions has_many :counties has_many :cities end class Region < ActiveRecord::Base has_one :country has_many :counties has_many :cities end class County < ActiveRecord::Base has_one :country has_one :region has_many :cities end class City < ActiveRecord::Base has_one :country has_one :region has_one :county end Would it be better to use the :through symbol in the association? So I could say the city: has_one :country, :through => :region Not sure if this is correct, I have read how :through works but I'm not sure if this is the best solution. I am a newbie and while I'm not struggling with the syntax and how things work, it would be good to get opinions on best practices and the way things should be done from some rails wizards! Thanks in advance.

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  • Master thesis in software engineering

    - by maya
    Hi everyone, I will be Master student and I look for a topic in software engineering for my thesis , I want a topic which is less programming and more analysis. I mean a topic without programming because I'm not professional in programming. I'm thinking in UML tools but I really don't have specific topic. any suggestion please any one help me thanks in advance

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  • Getting RPXNow and Facebook Open Graph to Play Nicely

    - by ramon.tayag
    A requirement to use the RPXNow is to set your Facebook application's connect url to http://mydomain.rpxnow.com. I was just trying to implement Facebook's Open Graph and I see that it tells you to set the Base Domain to the domain that will contain the app_id. However, Facebook does not allow these two domains to look different. When I try to set the base url to mydomain.com, I get this error: Validation failed. Base Domain is not valid. Connect URL must be derived from your Base Domain. Should I create two apps - one for use with RPXNow, and another for use with Open Graph? If not, what should I do? Thanks

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  • High-concurrency counters without sharding

    - by dound
    This question concerns two implementations of counters which are intended to scale without sharding (with a tradeoff that they might under-count in some situations): http://appengine-cookbook.appspot.com/recipe/high-concurrency-counters-without-sharding/ (the code in the comments) http://blog.notdot.net/2010/04/High-concurrency-counters-without-sharding My questions: With respect to #1: Running memcache.decr() in a deferred, transactional task seems like overkill. If memcache.decr() is done outside the transaction, I think the worst-case is the transaction fails and we miss counting whatever we decremented. Am I overlooking some other problem that could occur by doing this? What are the significiant tradeoffs between the two implementations? Here are the tradeoffs I see: #2 does not require datastore transactions. To get the counter's value, #2 requires a datastore fetch while with #1 typically only needs to do a memcache.get() and memcache.add(). When incrementing a counter, both call memcache.incr(). Periodically, #2 adds a task to the task queue while #1 transactionally performs a datastore get and put. #1 also always performs memcache.add() (to test whether it is time to persist the counter to the datastore). Conclusions (without actually running any performance tests): #1 should typically be faster at retrieving a counter (#1 memcache vs #2 datastore). Though #1 has to perform an extra memcache.add() too. However, #2 should be faster when updating counters (#1 datastore get+put vs #2 enqueue a task). On the other hand, with #1 you have to be a bit more careful with the update interval since the task queue quota is almost 100x smaller than either the datastore or memcahce APIs.

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  • Full-text search on App Engine with Whoosh

    - by Martin
    I need to do full text searching with Google App Engine. I found the project Whoosh and it works really well, as long as I use the App Engine Development Environement... When I upload my application to App Engine, I am getting the following TraceBack. For my tests, I am using the example application provided in this project. Any idea of what I am doing wrong? <type 'exceptions.ImportError'>: cannot import name loads Traceback (most recent call last): File "/base/data/home/apps/myapp/1.334374478538362709/hello.py", line 6, in <module> from whoosh import store File "/base/data/home/apps/myapp/1.334374478538362709/whoosh/__init__.py", line 17, in <module> from whoosh.index import open_dir, create_in File "/base/data/home/apps/myapp/1.334374478538362709/whoosh/index.py", line 31, in <module> from whoosh import fields, store File "/base/data/home/apps/myapp/1.334374478538362709/whoosh/store.py", line 27, in <module> from whoosh import tables File "/base/data/home/apps/myapp/1.334374478538362709/whoosh/tables.py", line 43, in <module> from marshal import loads Here is the import I have in my Python file. # Whoosh ---------------------------------------------------------------------- sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..', 'utils'))) from whoosh.fields import Schema, STORED, ID, KEYWORD, TEXT from whoosh.index import getdatastoreindex from whoosh.qparser import QueryParser, MultifieldParser Thank you in advance for your help!

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  • ListBox item doesn't get refresh in WPF?

    - by sanjeev40084
    I have a listbox which has couple of items. When double clicked on each item, the user get option to edit item (text of item). Now once i update the item, my item in listbox doesn't get updated. The first window (one which has listbox) is in MainWindow.xaml file and second window is in EditTaskView.xaml(one which let's edit the items text) file. The code that displays items in lists is: Main.Windows.cs public static ObservableCollection TaskList; public void GetTask() { TaskList = new ObservableCollection<Task> { new Task("Task1"), new Task("Task2"), new Task("Task3"), new Task("Task4") }; lstBxTask.ItemsSource = TaskList; } private void lstBxTask_MouseDoubleClick(object sender, MouseButtonEventArgs e) { var selectedTask = (Task)lstBxTask.SelectedItem; EditTask.txtBxEditedText.Text = selectedTask.Taskname; EditTask.PreviousTaskText = selectedTask.Taskname; EditTask.Visibility = Visibility.Visible; } The xaml code that displays the list: <ListBox x:Name="lstBxTask" Style="{StaticResource ListBoxItems}" MouseDoubleClick="lstBxTask_MouseDoubleClick"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel> <Rectangle Style="{StaticResource LineBetweenListBox}"/> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Taskname}" Style="{StaticResource TextInListBox}"/> <Button Name="btnDelete" Style="{StaticResource DeleteButton}" Click="btnDelete_Click"/> </StackPanel> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> <ToDoTask:EditTaskView x:Name="EditTask" Grid.Row="1" Grid.RowSpan="2" Grid.ColumnSpan="2" Visibility="Collapsed"/> The Save button in TaskEditView.xaml does this: public string PreviousTaskText { get; set; } private void btnSaveEditedText_Click(object sender, RoutedEventArgs e) { foreach (var t in MainWindow.TaskList) { if (t.Taskname == PreviousTaskText) { t.Taskname = txtBxEditedText.Text; } } Visibility = Visibility.Collapsed; } TaskList is the ObservableCollection, and i though once you update the value the UI gets refreshed. But doesn't seem to work that way. What am i missing?

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  • how to upgrade phing 'stable' to phing 'trunk' to use SSHTask

    - by Jorre
    phing 2.4.1 (current stable version) doesn't have an SSH Task to do remote scripting. In the current trunk version, there is a SSH Task that we would like to use. How can I upgrade my current phing installation (2.4.1) to the latest build? Can I use pear for that without breaking my current phing install? Or would it be better to download only the SSH Task and add that file manually to the stable phing install?

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  • Rails model relations depending on count of nested relations

    - by Lowgain
    I am putting together a messaging system for a rails app I am working on. I am building it in a similar fashion to facebook's system, so messages are grouped into threads, etc. My related models are: MsgThread - main container of a thread Message - each message/reply in thread Recipience - ties to user to define which users should subscribe to this thread Read - determines whether or not a user has read a specific message My relationships look like class User < ActiveRecord::Base #stuff... has_many :msg_threads, :foreign_key => 'originator_id' #threads the user has started has_many :recipiences has_many :subscribed_threads, :through => :recipiences, :source => :msg_thread #threads the user is subscribed to end class MsgThread < ActiveRecord::Base has_many :messages has_many :recipiences belongs_to :originator, :class_name => "User", :foreign_key => "originator_id" end class Recipience < ActiveRecord::Base belongs_to :user belongs_to :msg_thread end class Message < ActiveRecord::Base belongs_to :msg_thread belongs_to :author, :class_name => "User", :foreign_key => "author_id" end class Read < ActiveRecord::Base belongs_to :user belongs_to :message end I'd like to create a new selector in the user sort of like: has_many :updated_threads, :through => :recipiencies, :source => :msg_thread, :conditions => {THREAD CONTAINS MESSAGES WHICH ARE UNREAD (have no 'read' models tying a user to a message)} I was thinking of either writing a long condition with multiple joins, or possibly writing giving the model an updated_threads method to return this, but I'd like to see if there is an easier way first. Any ideas? Also, if there is something fundamentally wrong with my structure for this functionality let me know! Thanks!!

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  • How can I improve this design?

    - by klausbyskov
    Let's assume that our system can perform actions, and that an action requires some parameters to do its work. I have defined the following base class for all actions (simplified for your reading pleasure): public abstract class BaseBusinessAction<TActionParameters> : where TActionParameters : IActionParameters { protected BaseBusinessAction(TActionParameters actionParameters) { if (actionParameters == null) throw new ArgumentNullException("actionParameters"); this.Parameters = actionParameters; if (!ParametersAreValid()) throw new ArgumentException("Valid parameters must be supplied", "actionParameters"); } protected TActionParameters Parameters { get; private set; } protected abstract bool ParametersAreValid(); public void CommonMethod() { ... } } Only a concrete implementation of BaseBusinessAction knows how to validate that the parameters passed to it are valid, and therefore the ParametersAreValid is an abstract function. However, I want the base class constructor to enforce that the parameters passed are always valid, so I've added a call to ParametersAreValid to the constructor and I throw an exception when the function returns false. So far so good, right? Well, no. Code analysis is telling me to "not call overridable methods in constructors" which actually makes a lot of sense because when the base class's constructor is called the child class's constructor has not yet been called, and therefore the ParametersAreValid method may not have access to some critical member variable that the child class's constructor would set. So the question is this: How do I improve this design? Do I add a Func<bool, TActionParameters> parameter to the base class constructor? If I did: public class MyAction<MyParameters> { public MyAction(MyParameters actionParameters, bool something) : base(actionParameters, ValidateIt) { this.something = something; } private bool something; public static bool ValidateIt() { return something; } } This would work because ValidateIt is static, but I don't know... Is there a better way? Comments are very welcome.

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  • Single Form with Multiple Dynamic Buttons

    - by John Reilly
    I've spent hours/days trying to figure this out and now I'm completely perplexed so I thought I'd give stackoverflow a try. I'm (a newb) working in Java/JSP using Eclipse hosting on Google App Engine trying to develop an app for a volunteer organization I'm a member of. Rather than embarrass myself by showing my current code I'd love just a nudge in the right direction. I have a form (which doubles as a report basically) showing "people" grouped under the "task" they are currently working on. I would like to select multiple people from multiple tasks and reassign them to another task e.g. Bill and Jane are Gardening, Jeff is Painting. I want to select Jane and Jeff (all people have an associated checkbox in the form) and re-assign them to Sweeping (which is a task on the form but has no people assigned to it yet). Ideally, the re-assignment to Sweeping would be via a Sweeping button (each task would have a dynamically-created task button) that would pass the "Sweeping" value to a servlet along with an array or list of people whose checkbox has been checked. The servlet would handle the request (creating an Assignment "object/entity" with timeStamp, personId, taskId) and then re-direct back to the form/report which would then repaint with the current tasks/people generated from the Assignments class in the datastore. All the tasks are user-defined and retrieved from the database when building the form. Ditto the people. I've been trying to keep the jsp for presentation and the servlets for the processing but I'm no purist and would just like to get unstuck. Many thanks in advance for your assistance.

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  • How can I display multiple django modelformset forms in a grouped fieldsets?

    - by JT
    I have a problem with needing to provide multiple model backed forms on the same page. I understand how to do this with single forms, i.e. just create both the forms call them something different then use the appropriate names in the template. Now how exactly do you expand that solution to work with modelformsets? The wrinkle, of course, is that each 'form' must be rendered together in the appropriate fieldset. For example I want my template to produce something like this: <fieldset> <label for="id_base-0-desc">Home Base Description:</label> <input id="id_base-0-desc" type="text" name="base-0-desc" maxlength="100" /> <label for="id_likes-0-icecream">Want ice cream?</label> <input type="checkbox" name="likes-0-icecream" id="id_likes-0-icecream" /> </fieldset> <fieldset> <label for="id_base-1-desc">Home Base Description:</label> <input id="id_base-1-desc" type="text" name="base-1-desc" maxlength="100" /> <label for="id_likes-1-icecream">Want ice cream?</label> <input type="checkbox" name="likes-1-icecream" id="id_likes-1-icecream" /> </fieldset> I am using a loop like this to process the results (after form validation) base_models = base_formset.save(commit=False) like_models = like_formset.save(commit=False) for base_model, likes_model in map(None, base_models, likes_models): which works as I'd expect (I'm using map because the # of forms can be different). The problem is that I can't figure out a way to do the same thing with the templating engine. The system does work if I layout all the base models together then all the likes models after wards, but it doesn't meet the layout requirements. EDIT: Updated the problem statement to be more clear about what exactly I'm processing (I'm processing models not forms in the for loop)

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  • Code refactoring homework?

    - by Hira
    This is the code that I have to refactor for my homework: if (state == TEXAS) { rate = TX_RATE; amt = base * TX_RATE; calc = 2 * basis(amt) + extra(amt) * 1.05; } else if ((state == OHIO) || (state == MAINE)) { rate = (state == OHIO) ? OH_RATE : MN_RATE; amt = base * rate; calc = 2 * basis(amt) + extra(amt) * 1.05; if (state == OHIO) points = 2; } else { rate = 1; amt = base; calc = 2 * basis(amt) + extra(amt) * 1.05; } I have done something like this if (state == TEXAS) { rate = TX_RATE; calculation(rate); } else if ((state == OHIO) || (state == MAINE)) { rate = (state == OHIO) ? OH_RATE : MN_RATE; calculation(rate); if (state == OHIO) points = 2; } else { rate = 1; calculation(rate); } function calculation(rate) { amt = base * rate; calc = 2 * basis(amt) + extra(amt) * 1.05; } How could I have done better? Edit i have done code edit amt = base * rate;

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  • Can simple javascript inheritance be simplified even further?

    - by Will
    John Resig (of jQuery fame) provides a concise and elegant way to allow simple JavaScript inheritance. It was so short and sweet, in fact, that it inspired me to try and simplify it even further (see code below). I've modified his original function such that it still passes all his tests and has the potential advantage of: readability (50% less code) simplicity (you don't have to be a ninja to understand it) performance (no extra wrappers around super/base method calls) consistency with C#'s base keyword Because this seems almost too good to be true, I want to make sure my logic doesn't have any fundamental flaws/holes/bugs, or if anyone has additional suggestions to improve or refute the code (perhaps even John Resig could chime in here!). Does anyone see anything wrong with my approach (below) vs. John Resig's original approach? if (!window.Class) { window.Class = function() {}; window.Class.extend = function(members) { var prototype = new this(); for (var i in members) prototype[i] = members[i]; prototype.base = this.prototype; function object() { if (object.caller == null && this.initialize) this.initialize.apply(this, arguments); } object.constructor = object; object.prototype = prototype; object.extend = arguments.callee; return object; }; } And the tests (below) are nearly identical to the original ones except for the syntax around base/super method calls (for the reason enumerated above): var Person = Class.extend( { initialize: function(isDancing) { this.dancing = isDancing; }, dance: function() { return this.dancing; } }); var Ninja = Person.extend( { initialize: function() { this.base.initialize(false); }, dance: function() { return this.base.dance(); }, swingSword: function() { return true; } }); var p = new Person(true); alert("true? " + p.dance()); // => true var n = new Ninja(); alert("false? " + n.dance()); // => false alert("true? " + n.swingSword()); // => true alert("true? " + (p instanceof Person && p instanceof Class && n instanceof Ninja && n instanceof Person && n instanceof Class));

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  • Multi:Threading - Is this the right approach?

    - by HonorGod
    Experts - I need some advice in the following scenario. I have a configuration file with a list of tasks. Each task can have zero, one or more dependencies. I wanted to execute these tasks in parallel [right now they are being executed sequentially] The idea is to have a main program to read the configuration file and load all the tasks. Read individual tasks and give it to an executor [callable] that will perform the task and return results in a Future. When the task is submitted to the executor (thread) it will monitor for its dependencies to finish first and perform its own task. Is this the right approach? Are there any other better approaches using java 1.5 features?

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  • How do I program an AVR Raven with Linux or a Mac?

    - by Andrew McGregor
    This tutorial for programming these starts with programming the Ravens and Jackdaw with a Windows box. Can I do those initial steps with avrdude on a Linux or OS X machine instead? If so, how? Is there any risk of bricking the hardware if I just try? I have a USB JTAG ICE MKii clone, which is supposed to work for this. I'm totally new to AVR, but very experienced with C/C++ programming on Linux or OS X, up to and including kernel programming... so any hint at all would be appreciated, I can read man pages, but only if I know what I'm looking for.

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  • Combining data sets without losing observations in SAS

    - by John
    Hye guys, I know, another post another problem :D :(. I took a screenshot to easily explain my problem. http://i39.tinypic.com/rhms0h.jpg As you can see I want to merge two tables (again), the Base & Analyst table. What I want to achieve is displayed in the right bottom corner table. I’m calculating the number of total analysts and female analysts for each month in the analyst table. In the base table I have different observations for one company (here company Alcoa with ticker AA). When I use the following command: data want; merge base analyst; by month ; run; I get the right up corner problem. My observations in the main table are being narrowed down to only 4 observations (for each different year one observation, 2001, 2002, 2005, 2006). What I want is that the observations are not reduced but that for every year the same data is being placed as shown in the right bottom corner. What am I missing in my merge command? In both tables I have month as a time count variable ( the observations in my base table are monthly) on which I need to merge. For clarity I added 2 screenshots of my real databases in SAS. The base table: http://i42.tinypic.com/dr5jky.jpg The analyst table: http://i40.tinypic.com/eqpmqq.jpg Here is what my merged table looks like: http://i43.tinypic.com/116i62s.jpg You can clearly see that the merged table only has four observations left for AA (one for each unique year) instead of the original 8. Anyone an idea to solve this?

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  • Problem with between join for sqlalchemy orm relation.

    - by Gary van der Merwe
    I'm trying to create a relation that has a between join. Here is a shortish example of what I'm trying to do: #!/usr/bin/env python import sqlalchemy as sa from sqlalchemy import orm from sqlalchemy.engine.base import Engine from sqlalchemy.ext.declarative import declarative_base metadata = sa.MetaData() Base = declarative_base(metadata=metadata) engine = sa.create_engine('sqlite:///:memory:') class Network(Base): __tablename__ = "network" id = sa.Column(sa.Integer, primary_key=True) ip_net_addr_db = sa.Column('ip_net_addr', sa.Integer, index=True) ip_broadcast_addr_db = sa.Column('ip_broadcast_addr', sa.Integer, index=True) # This can be determined from the net address and the net mask, but we store # it in the db so that we can join with the address table. ip_net_mask_len = sa.Column(sa.SmallInteger) class Address(Base): __tablename__ = "address" ip_addr_db = sa.Column('ip_addr', sa.Integer, primary_key=True, index=True, unique=True) Network.addresses = orm.relation(Address, primaryjoin=Address.ip_addr_db.between( Network.ip_net_addr_db, Network.ip_broadcast_addr_db), foreign_keys=[Address.ip_addr_db]) metadata.create_all(engine) Session = orm.sessionmaker(bind=engine) Network() I you run this, you get this error: ArgumentError: Could not determine relation direction for primaryjoin condition 'address.ip_addr BETWEEN network.ip_net_addr AND network.ip_broadcast_addr', on relation Network.addresses. Do the columns in 'foreign_keys' represent only the 'foreign' columns in this join condition ? The answer to that question is Yes, but I cant figure out how to tell it that

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  • Weird generics compile error.

    - by Jouke van der Maas
    I have two classes, a base class and a child class. In the base class i define a generic virtual method: protected virtual Bar Foo<T() where T : Bar {} Then in my child class i try to do this: protected override BarChild Foo() // BarChild inherits Bar { return base.Bar<T as BarChild() } Visual studio gives this weird error: The type 'T' cannot be used as type parameter 'T' in the generic type or method 'Foo()'. There is no boxing conversion or type parameter conversion from 'T' to 'Bar'. Repeating the where clause on the child's override also gives an error: Constraints for override and explicit interface implementation methods are inherited from the base method, so they cannot be specified directly So what am i doing wrong here?

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  • Load a MySQL innodb database into memory

    - by jack
    I have a MySQL innodb database at 1.9GB, showed by following command. SELECT table_schema "Data Base Name", -> sum( data_length + index_length ) / 1024 / -> 1024 "Data Base Size in MB", -> sum( data_free )/ 1024 / 1024 "Free Space in MB" -> FROM information_schema.TABLES -> GROUP BY table_schema ; +--------------------+----------------------+------------------+ | Data Base Name | Data Base Size in MB | Free Space in MB | +--------------------+----------------------+------------------+ | database_name | 1959.73437500 | 31080.00000000 | My questions are: Does it mean if I set the innodb_buffer_pool_size to 2GB or larger, the whole database can be loaded into memory so much fewer read from disk requests are needed? What does the free space of 31GB mean? If the maximum RAM can be allocated to innodb_buffer_pool_size is 1GB, is it possible to specify which tables to loaded into memory while keep others always read from disk? Thanks in advance.

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  • Issues in Ada Concurrency

    - by Arkapravo
    Hi I need some help and also some insight. This is a program in Ada-2005 which has 3 tasks. The output is 'z'. If the 3 tasks do not happen in the order of their placement in the program then output can vary from z = 2, z = 1 to z = 0 ( That is easy to see in the program, mutual exclusion is attempted to make sure output is z = 2). WITH Ada.Text_IO; USE Ada.Text_IO; WITH Ada.Integer_Text_IO; USE Ada.Integer_Text_IO; WITH System; USE System; procedure xyz is x : Integer := 0; y : Integer := 0; z : Integer := 0; task task1 is pragma Priority(System.Default_Priority + 3); end task1; task task2 is pragma Priority(System.Default_Priority + 2); end task2; task task3 is pragma Priority(System.Default_Priority + 1); end task3; task body task1 is begin x := x + 1; end task1; task body task2 is begin y := x + y; end task2; task body task3 is begin z := x + y + z; end task3; begin Put(" z = "); Put(z); end xyz; I first tried this program (a) without pragmas, the result : In 100 tries, occurence of 2: 86, occurence of 1: 10, occurence of 0: 4. Then (b) with pragmas, the result : In 100 tries, occurence of 2: 84, occurence of 1 : 14, occurence of 0: 2. Which is unexpected as the 2 results are nearly identical. Which means pragmas or no pragmas the output has same behavior. Those who are Ada concurrency Gurus please shed some light on this topic. Alternative solutions with semaphores (if possible) is also invited. Further in my opinion for a critical process (that is what we do with Ada), with pragmas the result should be z = 2, 100% at all times, hence or otherwise this program should be termed as 85% critical !!!! (That should not be so with Ada)

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  • Rails 3 equivalent of complex SQL query

    - by Bryan
    Given the following models: class Recipe < ActiveRecord::Base has_many :recipe_ingredients has_many :ingredients, :through => :recipe_ingredients end class RecipeIngredient < ActiveRecord::Base belongs_to :recipe belongs_to :ingredient end class Ingredient < ActiveRecord::Base end How can I perform the following SQL query using Arel in Rails 3? SELECT * FROM recipes WHERE NOT EXISTS ( SELECT * FROM ingredients WHERE name IN ('chocolate', 'cream') AND NOT EXISTS ( SELECT * FROM recipe_ingredients WHERE recipe_ingredients.recipe_id = recipes.id AND recipe_ingredients.ingredient_id = ingredients.id))

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