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  • Abstract away a compound identity value for use in business logic?

    - by John K
    While separating business logic and data access logic into two different assemblies, I want to abstract away the concept of identity so that the business logic deals with one consistent identity without having to understand its actual representation in the data source. I've been calling this a compound identity abstraction. Data sources in this project are swappable and various and the business logic shouldn't care which data source is currently in use. The identity is the toughest part because its implementation can change per kind of data source, whereas other fields like name, address, etc are consistently scalar values. What I'm searching for is a good way to abstract the concept of identity, whether it be an existing library, a software pattern or just a solid good idea of some kind is provided. The proposed compound identity value would have to be comparable and usable in the business logic and passed back to the data source to specify records, entities and/or documents to affect, so the data source must be able to parse back out the details of its own compound ids. Data Source Examples: This serves to provide an idea of what I mean by various data sources having different identity implementations. A relational data source might express a piece of content with an integer identifier plus a language specific code. For example. content_id language Other Columns expressing details of content 1 en_us 1 fr_ca The identity of the first record in the above example is: 1 + en_us However when a NoSQL data source is substituted, it might somehow represent each piece of content with a GUID string 936DA01F-9ABD-4d9d-80C7-02AF85C822A8 plus language code of a different standardization, And a third kind of data source might use just a simple scalar value. So on and so forth, you get the idea.

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  • Explicit method tables in C# instead of OO - good? bad?

    - by FunctorSalad
    Hi! I hope the title doesn't sound too subjective; I absolutely do not mean to start a debate on OO in general. I'd merely like to discuss the basic pros and cons for different ways of solving the following sort of problem. Let's take this minimal example: you want to express an abstract datatype T with functions that may take T as input, output, or both: f1 : Takes a T, returns an int f2 : Takes a string, returns a T f3 : Takes a T and a double, returns another T I'd like to avoid downcasting and any other dynamic typing. I'd also like to avoid mutation whenever possible. 1: Abstract-class-based attempt abstract class T { abstract int f1(); // We can't have abstract constructors, so the best we can do, as I see it, is: abstract void f2(string s); // The convention would be that you'd replace calls to the original f2 by invocation of the nullary constructor of the implementing type, followed by invocation of f2. f2 would need to have side-effects to be of any use. // f3 is a problem too: abstract T f3(double d); // This doesn't express that the return value is of the *same* type as the object whose method is invoked; it just expresses that the return value is *some* T. } 2: Parametric polymorphism and an auxilliary class (all implementing classes of TImpl will be singleton classes): abstract class TImpl<T> { abstract int f1(T t); abstract T f2(string s); abstract T f3(T t, double d); } We no longer express that some concrete type actually implements our original spec -- an implementation is simply a type Foo for which we happen to have an instance of TImpl. This doesn't seem to be a problem: If you want a function that works on arbitrary implementations, you just do something like: // Say we want to return a Bar given an arbitrary implementation of our abstract type Bar bar<T>(TImpl<T> ti, T t); At this point, one might as well skip inheritance and singletons altogether and use a 3 First-class function table class /* or struct, even */ TDictT<T> { readonly Func<T,int> f1; readonly Func<string,T> f2; readonly Func<T,double,T> f3; TDict( ... ) { this.f1 = f1; this.f2 = f2; this.f3 = f3; } } Bar bar<T>(TDict<T> td; T t); Though I don't see much practical difference between #2 and #3. Example Implementation class MyT { /* raw data structure goes here; this class needn't have any methods */ } // It doesn't matter where we put the following; could be a static method of MyT, or some static class collecting dictionaries static readonly TDict<MyT> MyTDict = new TDict<MyT>( (t) => /* body of f1 goes here */ , // f2 (s) => /* body of f2 goes here */, // f3 (t,d) => /* body of f3 goes here */ ); Thoughts? #3 is unidiomatic, but it seems rather safe and clean. One question is whether there are any performance concerns with it. I don't usually need dynamic dispatch, and I'd prefer if these function bodies get statically inlined in places where the concrete implementing type is known statically. Is #2 better in that regard?

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  • "is not abstact and does not override abstract method."

    - by Chris Bolton
    So I'm pretty new to android development and have been trying to piece together some code bits. Here's what I have so far: package com.teslaprime.prirt; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.AdapterView.OnItemClickListener; import java.util.ArrayList; import java.util.List; public class TaskList extends Activity { List<Task> model = new ArrayList<Task>(); ArrayAdapter<Task> adapter = null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Button add = (Button) findViewById(R.id.add); add.setOnClickListener(onAdd); ListView list = (ListView) findViewById(R.id.tasks); adapter = new ArrayAdapter<Task>(this,android.R.layout.simple_list_item_1,model); list.setAdapter(adapter); list.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(View v, int position, long id) { adapter.remove(position); } });} private View.OnClickListener onAdd = new View.OnClickListener() { public void onClick(View v) { Task task = new Task(); EditText name = (EditText) findViewById(R.id.taskEntry); task.name = name.getText().toString(); adapter.add(task); } }; } and here are the errors I'm getting: compile: [javac] /opt/android-sdk/tools/ant/main_rules.xml:384: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds [javac] Compiling 2 source files to /home/chris-kun/code/priRT/bin/classes [javac] /home/chris-kun/code/priRT/src/com/teslaprime/prirt/TaskList.java:30: <anonymous com.teslaprime.prirt.TaskList$1> is not abstract and does not override abstract method onItemClick(android.widget.AdapterView<?>,android.view.View,int,long) in android.widget.AdapterView.OnItemClickListener [javac] list.setOnItemClickListener(new OnItemClickListener() { [javac] ^ [javac] /home/chris-kun/code/priRT/src/com/teslaprime/prirt/TaskList.java:32: remove(com.teslaprime.prirt.Task) in android.widget.ArrayAdapter<com.teslaprime.prirt.Task> cannot be applied to (int) [javac] adapter.remove(position); [javac] ^ [javac] 2 errors BUILD FAILED /opt/android-sdk/tools/ant/main_rules.xml:384: Compile failed; see the compiler error output for details. Total time: 2 seconds any ideas?

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  • How can i convert this to a factory/abstract factory?

    - by Amitd
    I'm using MigraDoc to create a pdf document. I have business entities similar to the those used in MigraDoc. public class Page{ public List<PageContent> Content { get; set; } } public abstract class PageContent { public int Width { get; set; } public int Height { get; set; } public Margin Margin { get; set; } } public class Paragraph : PageContent{ public string Text { get; set; } } public class Table : PageContent{ public int Rows { get; set; } public int Columns { get; set; } //.... more } In my business logic, there are rendering classes for each type public interface IPdfRenderer<T> { T Render(MigraDoc.DocumentObjectModel.Section s); } class ParagraphRenderer : IPdfRenderer<MigraDoc.DocumentObjectModel.Paragraph> { BusinessEntities.PDF.Paragraph paragraph; public ParagraphRenderer(BusinessEntities.PDF.Paragraph p) { paragraph = p; } public MigraDoc.DocumentObjectModel.Paragraph Render(MigraDoc.DocumentObjectModel.Section s) { var paragraph = s.AddParagraph(); // add text from paragraph etc return paragraph; } } public class TableRenderer : IPdfRenderer<MigraDoc.DocumentObjectModel.Tables.Table> { BusinessEntities.PDF.Table table; public TableRenderer(BusinessEntities.PDF.Table t) { table =t; } public MigraDoc.DocumentObjectModel.Tables.Table Render(Section obj) { var table = obj.AddTable(); //fill table based on table } } I want to create a PDF page as : var document = new Document(); var section = document.AddSection();// section is a page in pdf var page = GetPage(1); // get a page from business classes foreach (var content in page.Content) { //var renderer = createRenderer(content); // // get Renderer based on Business type ?? // renderer.Render(section) } For createRenderer() i can use switch case/dictionary and return type. How can i get/create the renderer generically based on type ? How can I use factory or abstract factory here? Or which design pattern better suits this problem?

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  • Is Abstract Factory Pattern implemented correctly for given scenario.... ???

    - by Amit
    First thing... I am novice to pattern world, so correct me if wrong anywhere Scenario: There are multiple companies providing multiple products of diff size so there are 3 entities i.e. Companies, Their Product and size of product I have implement Abstract Pattern on this i.e. so that I will create instance of IProductFactory interface to get desired product... Is below implementation of Abstract Factory Pattern correct ??? If not then please correct the approach + Also tell me if any other pattern can be used for such scenario Thanks in advance... public enum Companies { Samsung = 0, LG = 1, Philips = 2, Sony = 3 } public enum Product { PlasmaTv = 0, DVD = 1 } public enum ProductSize { FortyTwoInch, FiftyFiveInch } interface IProductFactory { IPhilips GetPhilipsProduct(); ISony GetSonyProduct(); } interface ISony { string CreateProducts(Product product, ProductSize size); } interface IPhilips { string CreateProducts(Product product, ProductSize size); } class ProductFactory : IProductFactory { public IPhilips GetPhilipsProduct() { return new Philips(); } public ISony GetSonyProduct() { return new Sony(); } } class Philips : IPhilips { #region IPhilips Members public string CreateProducts(Product product, ProductSize size) {// I have ingnore size for now.... string output = string.Empty; if (product == Product.PlasmaTv) { output = "Plasma TV Created !!!"; } else if (product == Product.DVD) { output = "DVD Created !!!"; } return output; } #endregion } class Sony : ISony {// I have ingnore size for now.... #region ISony Members public string CreateProducts(Product product, ProductSize size) { string output = string.Empty; if (product == Product.PlasmaTv) { output = "Plasma TV Created !!!"; } else if (product == Product.DVD) { output = "DVD Created !!!"; } return output; } #endregion } IProductFactory prodFactory = new ProductFactory(); IPhilips philipsObj = prodFactory.GetPhilipsProduct(); MessageBox.Show(philipsObj.CreateProducts(Product.DVD, ProductSize.FortyTwoInch)); or //ISony sonyObj = prodFactory.GetSonyProduct(); //MessageBox.Show(sonyObj.CreateProducts(Product.DVD, ProductSize.FortyTwoInch));

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  • Conceptual inheritance implementation

    - by TheSENDER
    Hi there, I'm writing a spatial data structure and I have a doubt about what's the best NODE implementation. According to my design I have an abstract node entity and three classes which inherit from it: EMPTYNODE, FULLNODE, INTERNALNODE. The first one has no particular data. The second one has 1 reference to a generic element. The third one has 2 references to other nodes. I have found several ways to implement this situation (that I have already coded) but I can't decide what's the best. The first solution that I have found is to use a single class Node that potentially performs all the operation in this way: private static class Node { private Elem elem = null; private Node left = null, right = null; public Elem getElem() { assert isFull(); return elem; } public boolean isEmpty() { return elem == null && left == null; } public boolean isFull() { return elem != null; } public boolean isInternal() { return elem == null && left != null; } } The second solution is to write an explicit division by classes where every class offers only its methods. Obviously in this way we are obliged to perform several casts to the node objects. private static abstract class Node { public abstract boolean isEmpty(); public abstract boolean isFull(); public abstract boolean isInternal(); } private static class FullNode extends Node{ private ITriangle elem; @Override public boolean isEmpty() { return false; } @Override public final boolean isFull() { return true; } @Override public final boolean isInternal() { return false; } public Elem getElem() { return elem; } } The third one solution is to use the inheritance allowing every classes to offer all the methods, but the object type should by check by "isEmpty()" and similar methods. In case of wrong call we'll throw an exception. private static abstract class Node { public abstract boolean isEmpty(); public abstract boolean isFull(); public abstract boolean isInternal(); public abstract Elem getElem(); } private static class Empty extends Node{ @Override public boolean isEmpty() { return true; } @Override public final boolean isFull() { return false; } @Override public final boolean isInternal() { return false; } @Override public Elem getElem() { throw new AssertionError(); } } What do you think about these three solutions? Which one would you use? Any other ideas? Thanks for your help. Every idea will be appreciated.

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  • Requesting feedback on my OO design

    - by Prog
    I'm working on an application that creates music by itself. I'm seeking feedback for my OO design so far. This question will focus on one part of the program. The application produces Tune objects, that are the final musical products. Tune is an abstract class with an abstract method play. It has two subclasses: SimpleTune and StructuredTune. SimpleTune owns a Melody and a Progression (chord sequence). It's play implementation plays these two objects simultaneously. StructuredTune owns two Tune instances. It's own play plays the two Tunes one after the other according to a pattern (currently only ABAB). Melody is an abstract class with an abstract play method. It has two subclasses: SimpleMelody and StructuredMelody. SimpleMelody is composed of an array of notes. Invoking play on it plays these notes one after the other. StructuredMelody is composed of an array of Melody objects. Invoking play on it plays these Melodyies one after the other. I think you're starting to see the pattern. Progression is also an abstract class with a play method and two subclasses: SimpleProgression and StructuredProgression, each composed differently and played differently. SimpleProgression owns an array of chords and plays them sequentially. StructuredProgression owns an array of Progressions and it's play implementation plays them sequentially. Every class has a corresponding Generator class. Tune, Melody and Progression are matched with corresponding abstract TuneGenerator, MelodyGenerator and ProgressionGenerator classes, each with an abstract generate method. For example MelodyGenerator defines an abstract Melody generate method. Each of the generators has two subclasses, Simple and Structured. So for example MelodyGenerator has a subclasses SimpleMelodyGenerator, with an implementation of generate that returns a SimpleMelody. (It's important to note that the generate methods encapsulate complex algorithms. They are more than mere factory method. For example SimpleProgressionGenerator.generate() implements an algorithm to compose a series of Chord objects, which are used to instantiate the returned SimpleProgression). Every Structured generator uses another generator internally. It is a Simple generator be default, but in special cases may be a Structured generator. Parts of this design are meant to allow the end-user through the GUI to choose what kind of music is to be created. For example the user can choose between a "simple tune" (SimpleTuneGenerator) and a "full tune" (StructuredTuneGenerator). Other parts of the system aren't subject to direct user-control. What do you think of this design from an OOD perspective? What potential problems do you see with this design? Please share with me your criticism, I'm here to learn. Apart from this, a more specific question: the "every class has a corresponding Generator class" part feels very wrong. However I'm not sure how I could design this differently and achieve the same flexibility. Any ideas?

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  • In Django, using __init__() method of non-abstract parent model to record class name of child model

    - by k-g-f
    In my Django project, I have a non-abstract parent model defined as follows: class Parent(models.Model): classType = models.CharField(editable=False,max_length=50) and, say, two children models defined as follows: class ChildA(Parent): parent = models.OneToOneField(Parent,parent_link=True) class ChildB(Parent): parent = models.OneToOneField(Parent,parent_link=True) Each time I create an instance of ChildA or of ChildB, I'd like the classType attribute to be set to the strings "ChildA" or "ChildB" respectively. What I have done is added an _ _ init_ _() method to Parent as follows: class Parent(models.Model): classType = models.CharField(editable=False,max_length=50) def __init__(self,*args,**kwargs): super(Parent,self).__init__(*args,**kwargs) self.classType = self.__class__.__name__ Is there a better way to implement and achieve my desired result? One downside of this implementation is that when I have an instance of the Parent, say "parent", and I want to get the type of the child object linked with "parent", calling "parent.classType" gives me "Parent". In order to get the appropriate "ChildA" or "ChildB" value, I need to write a "_getClassType()" method to wrap a custom sql query.

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  • Question concerning SCJP-6 exam

    - by abatishchev
    While preparing for the SCJP-6 exam I faced with a difficult issue. I can’t find answer by myself. Please, answer for the question and give short comments: abstract class A<K> extends Number> { // insert code here } public abstract <K> A<? extends Number> useMe(A<? super K> k); public abstract <K> A<? super Number> useMe(A<? extends K> k); public abstract <K> A<K> useMe(A<K> k); public abstract <V extends K> A<V> useMe(A<V> k); public abstract <V super K> A<V> useMe(A<V> k); public abstract <V extends Character> A<? super V> useMe(A<K> k); public abstract <V super Character> A<? super V> useMe(A<K> k); Which method can be inserted in a placeholder above? P.S. I tried to look on the specification. Those one was not helpful for me.

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  • Uninitialized constant Encoding with sqlite3-ruby on windows

    - by Ben Scheirman
    On a new machine, installed ruby with the 1-click installer for windows. Installed rails 2.3.2 and all associated gems, then I installed the sqlite3 binaries (into the c:\ruby\bin folder). Lastly I did gem install sqlite3-ruby -v=1.2.3 (which is apparently the latest version that works with windows) This error happens when I run rake db:migrate or when any ActiveRecord object is touched at runtime. The error looks like this: ** Invoke db:migrate (first_time) ** Invoke environment (first_time) ** Execute environment ** Execute db:migrate rake aborted! **uninitialized constant Encoding** <---- Any help resolving this error would be greatly appreciated! Trace: C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/dependencies.rb:443:in `load_missing_constant' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/dependencies.rb:80:in `const_missing' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/dependencies.rb:92:in `const_missing' C:/Ruby/lib/ruby/gems/1.8/gems/sqlite3-0.0.3/lib/sqlite3/encoding.rb:9:in `find' C:/Ruby/lib/ruby/gems/1.8/gems/sqlite3-0.0.3/lib/sqlite3/database.rb:69:in `initialize' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/sqlite3_adapter.rb:13:in `new' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/sqlite3_adapter.rb:13:in `sqlite3_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in `send' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in `new_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:245:in `checkout_new_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:188:in `checkout' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in `loop' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in `checkout' C:/Ruby/lib/ruby/1.8/monitor.rb:242:in `synchronize' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:183:in `checkout' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:98:in `connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:326:in `retrieve_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_specification.rb:123:in `retrieve_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_specification.rb:115:in `connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/migration.rb:435:in `initialize' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/migration.rb:400:in `new' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/migration.rb:400:in `up' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/migration.rb:383:in `migrate' C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.2/lib/tasks/databases.rake:116 C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain' C:/Ruby/lib/ruby/1.8/monitor.rb:242:in `synchronize' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31 C:/Ruby/bin/rake:19:in `load' C:/Ruby/bin/rake:19

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  • Rails Rake Error with XAMPP mysql database

    - by edu222
    I have installed XAAMP on my win7 machine and I have the apache server/mysql running on there. I set up rails to work with XAmpp as described here: XAMPP and RAILS This tutorial advises you to add this code to the XAMPP httpd.connf : Listen 3000 LoadModule rewrite_module modules/mod_rewrite.so ################################# # RUBY SETUP ################################# <virtualHost *:3000> ServerName rails DocumentRoot "c:/xampp/htdocs/FirstProject/public" <Directory "c:/xampp/htdocs/FirstProject/public/"> Options ExecCGI FollowSymLinks AllowOverride all Allow from all Order allow,deny AddHandler cgi-script .cgi AddHandler fastcgi-script .fcgi </Directory> </VirtualHost> ################################# # RUBY SETUP ################################# Xampp runs on the default localhost and mysql remains unchanged without a pw. I created a rails app with a mysql database like this: rails -d mysql C:/xampp/htdocs/FirstProject Then I started the ruby script/server from within the FirstProject location The localhost:3000/ shows the classic rails welcome I then ran a basic scaffold command: ruby script/generate scaffold FirstProject name:string email:string <br/> When I run the rake db:migrate command I get the following error: C:\xampp\htdocs\FirstProject>rake db:migrate --trace (in C:/xampp/htdocs/FirstProject) ** Invoke db:migrate (first_time) ** Invoke environment (first_time) ** Execute environment ** Execute db:migrate rake aborted! undefined method `init' for Mysql:Class C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/mysql_adapter.rb:70:in `mysql_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_pool.rb:223:in `send' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_pool.rb:223:in `new_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_pool.rb:245:in `checkout_new_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_pool.rb:188:in `checkout' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_pool.rb:184:in `loop' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_pool.rb:184:in `checkout' C:/Ruby/lib/ruby/1.8/monitor.rb:242:in `synchronize' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_pool.rb:183:in `checkout' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_pool.rb:98:in `connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_pool.rb:326:in `retrieve_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_specification.rb:123:in `retrieve_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_a dapters/abstract/connection_specification.rb:115:in `connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb :435:in `initialize' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb :400:in `new' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb :400:in `up' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb :383:in `migrate' C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/tasks/databases.rake:116 C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_c hain' C:/Ruby/lib/ruby/1.8/monitor.rb:242:in `synchronize' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_c hain' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exceptio n_handling' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exceptio n_handling' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run' C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31 C:/Ruby/bin/rake:19:in `load' C:/Ruby/bin/rake:19 Any idea on how to fix this? Thanks in advance

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  • migrating simple rails database to mysql

    - by joseph-misiti
    i am interested in creating a rails app with a mysql database. i am new to rails and am just trying to start creating something simple: rails -d mysql MyMoviesSQL cd MyMoviesSQL script/generate scaffold Movies title:string rating:integer rake db:migrate i am seeing the following error: rake aborted! NoMethodError: undefined method `ord' for 0:Fixnum: SET NAMES 'utf8' if i do a trace: ** Invoke db:migrate (first_time) ** Invoke environment (first_time) ** Execute environment ** Execute db:migrate rake aborted! NoMethodError: undefined method ord' for 0:Fixnum: SET NAMES 'utf8' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract_adapter.rb:219:inlog' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/mysql_adapter.rb:323:in execute' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/mysql_adapter.rb:599:inconfigure_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/mysql_adapter.rb:594:in connect' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/mysql_adapter.rb:203:ininitialize' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/mysql_adapter.rb:75:in new' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/mysql_adapter.rb:75:inmysql_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in send' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:innew_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:245:in checkout_new_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:188:incheckout' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in loop' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:incheckout' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in synchronize' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:183:incheckout' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:98:in connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:326:inretrieve_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_specification.rb:123:in retrieve_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_specification.rb:115:inconnection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb:435:in initialize' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb:400:innew' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb:400:in up' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb:383:inmigrate' /Library/Ruby/Gems/1.8/gems/rails-2.3.5/lib/tasks/databases.rake:116 /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in call' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:inexecute' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in each' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:inexecute' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in invoke_with_call_chain' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:insynchronize' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in invoke_with_call_chain' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:ininvoke' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in invoke_task' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:intop_level' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in each' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:intop_level' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in standard_exception_handling' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:intop_level' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in run' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:instandard_exception_handling' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in run' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/bin/rake:31 /usr/bin/rake:19:inload' /usr/bin/rake:19 here are my versions: rails - 2.3.5 ruby - 1.8.6 gem list * LOCAL GEMS * actionmailer (2.3.5, 1.3.6) actionpack (2.3.5, 1.13.6) actionwebservice (1.2.6) activerecord (2.3.5, 1.15.6) activeresource (2.3.5) activesupport (2.3.5, 1.4.4) acts_as_ferret (0.4.1) capistrano (2.0.0) cgi_multipart_eof_fix (2.5.0) daemons (1.0.9) dbi (0.4.3) deprecated (2.0.1) dnssd (0.6.0) fastthread (1.0.1) fcgi (0.8.7) ferret (0.11.4) gem_plugin (0.2.3) highline (1.2.9) hpricot (0.6) libxml-ruby (0.9.5, 0.3.8.4) mongrel (1.1.4) needle (1.3.0) net-sftp (1.1.0) net-ssh (1.1.2) rack (1.0.1) rails (2.3.5) rake (0.8.7, 0.7.3) RedCloth (3.0.4) ruby-openid (1.1.4) ruby-yadis (0.3.4) rubygems-update (1.3.6) rubynode (0.1.3) sqlite3-ruby (1.2.1) termios (0.9.4) also, if i need to add a patch to FixNum, can someone please tell which file to add the patch to. thanks for your help

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  • Migrating from a single entity to an abstract parent entity with child entities, NSEntityMigrationPolicy not called.

    - by Jimmy Selgen Nielsen
    Hi. I'm trying to upgrade my current application to use an abstract parent entity, with specialized sub entities. I've created a custom NSEntityMigrationPolicy, and in the mapping model I've set the Custom Policy to the name of my class. I'm initializing my persistent store like this, which should be fairly standard : NSError *error=nil; persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]]; NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, nil]; if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:options error:&error]) { NSLog(@"Error adding persistent store : %@",[error description]); NSAssert(error==nil,[error localizedDescription]); } When i run the app i get the following error : Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'The operation couldn’t be completed. (Cocoa error 134140.)' [error userInfo] contains "reason=Can't find mapping model for migration" I've verified that version 1 of the data model will open, and if i set NSInferMappingModelAutomaticallyOption i get a migration, although my entities are not migrated correctly (as expected). I've verified that the mapping model (cdm) is in the application bundle, but somehow it refuses to find it. I've also set breakpoints and NSLog() statements in the custom migration policy, and none of it runs, with or without NSInferMappingModelAutomaticallyOption Any hints as to why it seems unable to find the mapping model ?

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  • VC9 C1083 Cannot open include file: 'boost...' after trying to abstract an include dependency

    - by ronivek
    Hey, So I've been working on a project for the past number of weeks and it uses a number of Boost libraries. In particular I'm using the boost::dynamic_bitset library quite extensively. I've had zero issues up until now; but tonight I discovered a dependency between some includes which I had to resolve; and I tried to do so by providing an abstract callback class. Effectively I now have the following: First include... class OtherClassCallback { public: virtual int someOtherMethod() const = 0; }; class SomeClass { public: void someMethod(OtherClassCallback *oc) { ... oc->someOtherMethod(); ... } }; Second include... #include "SomeClass.h" class SomeOtherClass : public OtherClassCallback { public: int someOtherMethod() const { return this->someInt; } }; Here is the issue; ever since I implemented this class I'm now getting the following error: fatal error C1083: Cannot open include file: 'boost/dynamic_bitset/dynamic_bitset.hpp': No such file or directory Now I'm getting no other compiler errors; and it's a pretty substantial project. My include paths and so on are perfect; my files are fully accessible and removing the changes fixes the issue. Does anyone have any idea what might be going on? I'm compiling to native Windows executables in VS9. I should confess that I'm very inexperienced with C++ in general so go easy on me if it's something horribly straightforward; I can't figure it out.

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  • How should I map an abstract class with simple xml in Java?

    - by spderosso
    Hi, I want to achieve the following xml using simple xml framework (http://simple.sourceforge.net/): <events> <course-added date="01/01/2010"> ... </course-added> <course-removed date="01/02/2010"> .... </course-removed> <student-enrolled date="01/02/2010"> ... </student-enrolled> </events> I have the following (but it doesn't achieve the desired xml): @Root(name="events") class XMLEvents { @ElementList(inline=true) ArrayList<XMLEvent> events = Lists.newArrayList(); ... } abstract class XMLEvent { @Attribute(name="date") String dateOfEventFormatted; ... } And different type of XMLNodes that have different information (but are all different types of events) @Root(name="course-added") class XMLCourseAdded extends XMLEvent{ @Element(name="course") XMLCourseLongFormat course; .... } @Root(name="course-removed") class XMLCourseRemoved extends XMLEvent { @Element(name="course-id") String courseId; ... } How should I do the mapping or what should I change in order to be able to achieve de desired xml? Thanks!

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  • Abstract Data Type: Any1 can help me this? thanks..

    - by Aga Hibaya
    Objectives: Implement the Abstract Data Type (ADT) List using dynamically allocated arrays and structures. Description A LIST is an ordered collection of items where items may be inserted anywhere in the list. Implement a LIST using an array as follows: struct list { int *items; // pointer to the array int size; // actual size of the array int count; // number of items in the array }; typedef struct list *List; // pointer to the structure Implement the following functions: a) List newList(int size); - will create a new List and return its pointer. Allocate space for the structure, allocate space for the array, then initialize size and count, return the pointer. b) void isEmpty(List list); c) void display(List list); d) int contains(List list, int item); e) void remove(List list, int i) ; f) void insertAfter(List list,int item, int i); g) void addEnd(List list,int item) - add item at the end of the list – simply store the data at position count, then increment count. If the array is full, allocate an array twice as big as the original. count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 addEnd(list,40) will result to count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 40 h) void addFront(List list,int item) - shift all elements to the right so that the item can be placed at position 0, then increment count. Bonus: if the array is full, allocate an array twice as big as the original. count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 addFront(list,40) will result to count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 10 15 20 30 i) void removeFront(List list) - shift all elements to the left and decrement count; count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 10 15 20 30 removeFront(list) will result to count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 j) void remove(List list,int item) - get the index of the item in the list and then shift all elements to the count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 10 15 20 30 remove(list,10) will result to count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 15 20 30 Remarks

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  • How do I refactor these two C# functions to abstract their logic from the specific class properties

    - by ObligatoryMoniker
    I have two functions whose underlying logic is the same but in one case it sets one property value on a class and in another case it sets a different one. How can I rewrite the following two functions to abstract away as much of the algorithm as possible so that I can make changes in logic in a single place? SetBillingAddress private void SetBillingAddress(OrderAddress newBillingAddress) { BasketHelper basketHelper = new BasketHelper(SiteConstants.BasketName); OrderAddress oldBillingAddress = basketHelper.Basket.Addresses[basketHelper.BillingAddressID]; bool NewBillingAddressIsNotOldBillingAddress = ((oldBillingAddress == null) || (newBillingAddress.OrderAddressId != oldBillingAddress.OrderAddressId)); bool BillingAddressHasBeenPreviouslySet = (oldBillingAddress != null); bool BillingAddressIsNotSameAsShippingAddress = (basketHelper.ShippingAddressID != basketHelper.BillingAddressID); bool NewBillingAddressIsNotShippingAddress = (newBillingAddress.OrderAddressId != basketHelper.ShippingAddressID); if (NewBillingAddressIsNotOldBillingAddress && BillingAddressHasBeenPreviouslySet && BillingAddressIsNotSameAsShippingAddress) { basketHelper.Basket.Addresses.Remove(oldBillingAddress); } if (NewBillingAddressIsNotOldBillingAddress && NewBillingAddressIsNotShippingAddress) { basketHelper.Basket.Addresses.Add(newBillingAddress); } basketHelper.BillingAddressID = newBillingAddress.OrderAddressId; basketHelper.Basket.Save(); } And here is the second one: SetShippingAddress private void SetBillingAddress(OrderAddress newShippingAddress) { BasketHelper basketHelper = new BasketHelper(SiteConstants.BasketName); OrderAddress oldShippingAddress = basketHelper.Basket.Addresses[basketHelper.ShippingAddressID]; bool NewShippingAddressIsNotOldShippingAddress = ((oldShippingAddress == null) || (newShippingAddress.OrderAddressId != oldShippingAddress.OrderAddressId)); bool ShippingAddressHasBeenPreviouslySet = (oldShippingAddress != null); bool ShippingAddressIsNotSameAsBillingAddress = (basketHelper.ShippingAddressID != basketHelper.BillingAddressID); bool NewShippingAddressIsNotBillingAddress = (newShippingAddress.OrderAddressId != basketHelper.BillingAddressID); if (NewShippingAddressIsNotOldShippingAddress && ShippingAddressHasBeenPreviouslySet && ShippingAddressIsNotSameAsBillingAddress) { basketHelper.Basket.Addresses.Remove(oldShippingAddress); } if (NewShippingAddressIsNotOldShippingAddress && NewShippingAddressIsNotBillingAddress) { basketHelper.Basket.Addresses.Add(newShippingAddress); } basketHelper.ShippingAddressID = newShippingAddress.OrderAddressId; basketHelper.Basket.Save(); } My initial thought was that if I could pass a class's property by refernce then I could rewrite the previous functions into something like private void SetPurchaseOrderAddress(OrderAddress newAddress, ref String CurrentChangingAddressIDProperty) and then call this function and pass in either basketHelper.BillingAddressID or basketHelper.ShippingAddressID as CurrentChangingAddressIDProperty but since I can't pass C# properties by reference I am not sure what to do with this code to be able to reuse the logic in both places. Thanks for any insight you can give me.

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  • Abstract class and an inheritor: is it possible to factorize .parent() here?

    - by fge
    Here are what I think are the relevant parts of the code of these two classes. First, TreePointer (original source here): public abstract class TreePointer<T extends TreeNode> implements Iterable<TokenResolver<T>> { //... /** * What this tree can see as a missing node (may be {@code null}) */ private final T missing; /** * The list of token resolvers */ protected final List<TokenResolver<T>> tokenResolvers; /** * Main protected constructor * * <p>This constructor makes an immutable copy of the list it receives as * an argument.</p> * * @param missing the representation of a missing node (may be null) * @param tokenResolvers the list of reference token resolvers */ protected TreePointer(final T missing, final List<TokenResolver<T>> tokenResolvers) { this.missing = missing; this.tokenResolvers = ImmutableList.copyOf(tokenResolvers); } /** * Alternate constructor * * <p>This is the same as calling {@link #TreePointer(TreeNode, List)} with * {@code null} as the missing node.</p> * * @param tokenResolvers the list of token resolvers */ protected TreePointer(final List<TokenResolver<T>> tokenResolvers) { this(null, tokenResolvers); } //... /** * Tell whether this pointer is empty * * @return true if the reference token list is empty */ public final boolean isEmpty() { return tokenResolvers.isEmpty(); } @Override public final Iterator<TokenResolver<T>> iterator() { return tokenResolvers.iterator(); } // .equals(), .hashCode(), .toString() follow } Then, JsonPointer, which contains this .parent() method which I'd like to factorize here (original source here: public final class JsonPointer extends TreePointer<JsonNode> { /** * The empty JSON Pointer */ private static final JsonPointer EMPTY = new JsonPointer(ImmutableList.<TokenResolver<JsonNode>>of()); /** * Return an empty JSON Pointer * * @return an empty, statically allocated JSON Pointer */ public static JsonPointer empty() { return EMPTY; } //... /** * Return the immediate parent of this JSON Pointer * * <p>The parent of the empty pointer is itself.</p> * * @return a new JSON Pointer representing the parent of the current one */ public JsonPointer parent() { final int size = tokenResolvers.size(); return size <= 1 ? EMPTY : new JsonPointer(tokenResolvers.subList(0, size - 1)); } // ... } As mentioned in the subject, the problem I have here is with JsonPointer's .parent() method. In fact, the logic behind this method applies to TreeNode all the same, and therefore to its future implementations. Except that I have to use a constructor, and of course such a constructor is implementation dependent :/ Is there a way to make that .parent() method available to each and every implementation of TreeNode or is it just a pipe dream?

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  • Ruby on Rails tutorial problem

    - by RailAddict
    Quick question which I hope is easily answered.. I am following this tutorial: http://oreilly.com/pub/a/ruby/archive/rails.html?page=2 and all is going well until I try create a controller and view it in my browser. The server is running and it shows the default page okay (http://127.0.0.1:3000). I ran ruby script\generate controller MyTest in my command line and it generated the correct folders and files. The problem is, when I go to http://127.0.0.1:3000/My%5FTest/ it says: We're sorry, but something went wrong. We've been notified about this issue and we'll take a look at it shortly. This must be something I have overlooked somewhere. Any help is appreciated! ruby 1.8.6 rails 2.3.4 Just checked my development logs. Here is what it says: /!\ FAILSAFE /!\ Thu Sep 24 02:21:04 +0100 2009 Status: 500 Internal Server Error no such file to load -- sqlite3 C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in require' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/dependencies.rb:156:in require' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/dependencies.rb:521:in new_constants_in' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/dependencies.rb:156:in require' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/core_ext/kernel/requires.rb:7:in require_library_or_gem' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/core_ext/kernel/reporting.rb:11:in silence_warnings' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/core_ext/kernel/requires.rb:5:in require_library_or_gem' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/sqlite3_adapter.rb:10:in sqlite3_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in send' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in new_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:245:in checkout_new_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:188:in checkout' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in loop' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in checkout' C:/Ruby/lib/ruby/1.8/monitor.rb:242:in synchronize' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:183:in checkout' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:98:in connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:326:in retrieve_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_specification.rb:123:in retrieve_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_specification.rb:115:in connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/query_cache.rb:9:in cache' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/query_cache.rb:28:in call' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:361:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/head.rb:9:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/methodoverride.rb:24:in call' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/params_parser.rb:15:in call' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/session/cookie_store.rb:93:in call' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/failsafe.rb:26:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in synchronize' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in call' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/dispatcher.rb:114:in call' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/reloader.rb:34:in run' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/dispatcher.rb:108:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.4/lib/rails/rack/static.rb:31:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:46:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:40:in each' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:40:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.4/lib/rails/rack/log_tailer.rb:17:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/content_length.rb:13:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/handler/webrick.rb:46:in service' C:/Ruby/lib/ruby/1.8/webrick/httpserver.rb:104:in service' C:/Ruby/lib/ruby/1.8/webrick/httpserver.rb:65:in run' C:/Ruby/lib/ruby/1.8/webrick/server.rb:173:in start_thread' C:/Ruby/lib/ruby/1.8/webrick/server.rb:162:in start' C:/Ruby/lib/ruby/1.8/webrick/server.rb:162:in start_thread' C:/Ruby/lib/ruby/1.8/webrick/server.rb:95:in start' C:/Ruby/lib/ruby/1.8/webrick/server.rb:92:in each' C:/Ruby/lib/ruby/1.8/webrick/server.rb:92:in start' C:/Ruby/lib/ruby/1.8/webrick/server.rb:23:in start' C:/Ruby/lib/ruby/1.8/webrick/server.rb:82:in start' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/handler/webrick.rb:13:in run' C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.4/lib/commands/server.rb:111 C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require' script/server:3 I have no idea what this means but one thing I noticed is that it says sqlite3 - I am not using that. I am using MySql. Not sure if this is the problem..

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  • Snow Leopard & Ruby on Rails - SQLite3 issue

    - by spin-docta
    I just upgraded to snow leopard. Before, I had everything running fine, but now when I start the server from the terminal I get: => Booting WEBrick => Rails 2.3.3 application starting on http://0.0.0.0:3000 => Call with -d to detach => Ctrl-C to shutdown server [2009-08-28 23:18:19] INFO WEBrick 1.3.1 [2009-08-28 23:18:19] INFO ruby 1.8.7 (2008-08-11) [universal-darwin10.0] [2009-08-28 23:18:19] INFO WEBrick::HTTPServer#start: pid=845 port=3000 Then when I got to generated page, it seems like it isn't working with sqlite3. How do I fix? Here's what the server prints out when I go to a scripted view page: /!\ FAILSAFE /!\ Fri Aug 28 23:18:34 -0400 2009 Status: 500 Internal Server Error uninitialized constant SQLite3::Driver::Native::Driver::API /Library/Ruby/Gems/1.8/gems/activesupport-2.3.3/lib/active_support/dependencies.rb:105:in `const_missing' /Library/Ruby/Gems/1.8/gems/sqlite3-ruby-1.2.5/lib/sqlite3/driver/native/driver.rb:76:in `open' /Library/Ruby/Gems/1.8/gems/sqlite3-ruby-1.2.5/lib/sqlite3/database.rb:76:in `initialize' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/sqlite3_adapter.rb:13:in `new' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/sqlite3_adapter.rb:13:in `sqlite3_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in `send' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in `new_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:245:in `checkout_new_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:188:in `checkout' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in `loop' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in `checkout' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:183:in `checkout' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:98:in `connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:326:in `retrieve_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_specification.rb:123:in `retrieve_connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_specification.rb:115:in `connection' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/query_cache.rb:9:in `cache' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/query_cache.rb:28:in `call' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:361:in `call' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/head.rb:9:in `call' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/methodoverride.rb:24:in `call' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.3/lib/action_controller/params_parser.rb:15:in `call' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.3/lib/action_controller/session/cookie_store.rb:93:in `call' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.3/lib/action_controller/reloader.rb:29:in `call' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.3/lib/action_controller/failsafe.rb:26:in `call' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in `call' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in `synchronize' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in `call' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.3/lib/action_controller/dispatcher.rb:106:in `call' /Library/Ruby/Gems/1.8/gems/rails-2.3.3/lib/rails/rack/static.rb:31:in `call' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:46:in `call' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:40:in `each' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:40:in `call' /Library/Ruby/Gems/1.8/gems/rails-2.3.3/lib/rails/rack/log_tailer.rb:17:in `call' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/content_length.rb:13:in `call' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/handler/webrick.rb:46:in `service' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/webrick/server.rb:173:in `start_thread' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/webrick/server.rb:162:in `start' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/webrick/server.rb:162:in `start_thread' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/webrick/server.rb:95:in `start' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/webrick/server.rb:92:in `each' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/webrick/server.rb:92:in `start' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/webrick/server.rb:23:in `start' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/webrick/server.rb:82:in `start' /Library/Ruby/Gems/1.8/gems/rack-1.0.0/lib/rack/handler/webrick.rb:13:in `run' /Library/Ruby/Gems/1.8/gems/rails-2.3.3/lib/commands/server.rb:111 /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `require' script/server:3

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  • .NET 4.0 Generic Invariant, Covariant, Contravariant

    - by Sameer Shariff
    Here's the scenario i am faced with: public abstract class Record { } public abstract class TableRecord : Record { } public abstract class LookupTableRecord : TableRecord { } public sealed class UserRecord : LookupTableRecord { } public interface IDataAccessLayer<TRecord> where TRecord : Record { } public interface ITableDataAccessLayer<TTableRecord> : IDataAccessLayer<TTableRecord> where TTableRecord : TableRecord { } public interface ILookupTableDataAccessLayer<TLookupTableRecord> : ITableDataAccessLayer<TLookupTableRecord> where TLookupTableRecord : LookupTableRecord { } public abstract class DataAccessLayer<TRecord> : IDataAccessLayer<TRecord> where TRecord : Record, new() { } public abstract class TableDataAccessLayer<TTableRecord> : DataAccessLayer<TTableRecord>, ITableDataAccessLayer<TTableRecord> where TTableRecord : TableRecord, new() { } public abstract class LookupTableDataAccessLayer<TLookupTableRecord> : TableDataAccessLayer<TLookupTableRecord>, ILookupTableDataAccessLayer<TLookupTableRecord> where TLookupTableRecord : LookupTableRecord, new() { } public sealed class UserDataAccessLayer : LookupTableDataAccessLayer<UserRecord> { } Now when i try to cast UserDataAccessLayer to it's generic base type ITableDataAccessLayer<TableRecord>, the compiler complains that it cannot implicitly convert the type.

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  • Best Design Pattern for Coupling User Interface Components and Data Structures

    - by szahn
    I have a windows desktop application with a tree view. Due to lack of a sound data-binding solution for a tree view, I've implemented my own layer of abstraction on it to bind nodes to my own data structure. The requirements are as follows: Populate a tree view with nodes that resemble fields in a data structure. When a node is clicked, display the appropriate control to modify the value of that property in the instance of the data structure. The tree view is populated with instances of custom TreeNode classes that inherit from TreeNode. The responsibility of each custom TreeNode class is to (1) format the node text to represent the name and value of the associated field in my data structure, (2) return the control used to modify the property value, (3) get the value of the field in the control (3) set the field's value from the control. My custom TreeNode implementation has a property called "Control" which retrieves the proper custom control in the form of the base control. The control instance is stored in the custom node and instantiated upon first retrieval. So each, custom node has an associated custom control which extends a base abstract control class. Example TreeNode implementation: //The Tree Node Base Class public abstract class TreeViewNodeBase : TreeNode { public abstract CustomControlBase Control { get; } public TreeViewNodeBase(ExtractionField field) { UpdateControl(field); } public virtual void UpdateControl(ExtractionField field) { Control.UpdateControl(field); UpdateCaption(FormatValueForCaption()); } public virtual void SaveChanges(ExtractionField field) { Control.SaveChanges(field); UpdateCaption(FormatValueForCaption()); } public virtual string FormatValueForCaption() { return Control.FormatValueForCaption(); } public virtual void UpdateCaption(string newValue) { this.Text = Caption; this.LongText = newValue; } } //The tree node implementation class public class ExtractionTypeNode : TreeViewNodeBase { private CustomDropDownControl control; public override CustomControlBase Control { get { if (control == null) { control = new CustomDropDownControl(); control.label1.Text = Caption; control.comboBox1.Items.Clear(); control.comboBox1.Items.AddRange( Enum.GetNames( typeof(ExtractionField.ExtractionType))); } return control; } } public ExtractionTypeNode(ExtractionField field) : base(field) { } } //The custom control base class public abstract class CustomControlBase : UserControl { public abstract void UpdateControl(ExtractionField field); public abstract void SaveChanges(ExtractionField field); public abstract string FormatValueForCaption(); } //The custom control generic implementation (view) public partial class CustomDropDownControl : CustomControlBase { public CustomDropDownControl() { InitializeComponent(); } public override void UpdateControl(ExtractionField field) { //Nothing to do here } public override void SaveChanges(ExtractionField field) { //Nothing to do here } public override string FormatValueForCaption() { //Nothing to do here return string.Empty; } } //The custom control specific implementation public class FieldExtractionTypeControl : CustomDropDownControl { public override void UpdateControl(ExtractionField field) { comboBox1.SelectedIndex = comboBox1.FindStringExact(field.Extraction.ToString()); } public override void SaveChanges(ExtractionField field) { field.Extraction = (ExtractionField.ExtractionType) Enum.Parse(typeof(ExtractionField.ExtractionType), comboBox1.SelectedItem.ToString()); } public override string FormatValueForCaption() { return string.Empty; } The problem is that I have "generic" controls which inherit from CustomControlBase. These are just "views" with no logic. Then I have specific controls that inherit from the generic controls. I don't have any functions or business logic in the generic controls because the specific controls should govern how data is associated with the data structure. What is the best design pattern for this?

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