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  • What database is a good progression from MS Access for Coldfusion?

    - by Saul
    All my (home) CF learning has so far been done using Access as a database, and as far as the DB goes I "get it". There's no database server, and no need to log on to the database or anything, and setting up table relationships is easy and visual. Oh and its essentially free to deploy. However, I'm now working on an application that's likely to be used across several businesses and probably up to 50 concurrent users. I've heard that Access really isn't up to multi user use or production use on an app. What would you recommend as more suitable, preferably easy to grasp, with minimal tweeking needed for my SQL (I used a tool to convert to MySQL and it certainly handles concatenation differently, I dont want to have to do too much debugging), visual interface available, scalable, backupable, and whatever else I need that I don't yet know I need!

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  • DataMapper: using auto_migrate! with many-to-many dependencies?

    - by pschuegr
    Hi, I'm trying to migrate my app from MySql to Postgresql, using Rails3-pre and the latest DataMapper. I have several models which are related through many-to-many relationships using :through = Resource, which means that DataMapper creates a join table with foreign keys for both models. I can't auto_migrate! these changes, because I keep getting this: ERROR: cannot drop table users because other objects depend on it DETAIL: constraint artist_users_owner_fk on table artist_users depends on table users constraint site_users_owner_fk on table site_users depends on table users HINT: Use DROP ... CASCADE to drop the dependent objects too. I have tried everything I can think of, and thought I had things working when I added :constraint = :skip to the field definition, but I keep getting that error back when I try and run auto_migrate. I thought that :skip meant that it would ignore the dependents, but maybe that only applies for deleting rows and not dropping tables? I should mention that I can run auto_migrate after i nuke the db once, but after that, errors. Any suggestions or advice much appreciated.

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  • Drawing outlines around organic shapes

    - by ThunderChunky_SF
    One thing that seems particularly easy to do in the Flash IDE but difficult to do with code is to outline an organic shape. In the IDE you can just use the inkbucket tool to draw a stroke around something. Using nothing but code it seems much trickier. One method I've seen is to add a glow filter to the shape in question and just mess with the strength. But what if i want to only show the outline? What I'd like to do is to collect all of the points that make up the edge of the shape and then just connect the dots. I've actually gotten so far as to collect all of the points with a quick and dirty edge detection script that I wrote. So now I have a Vector of all the points that makeup my shape. How do I connect them in the proper sequence so it actually looks like the original object? For anyone who is interested here is my edge detection script: // Create a new sprite which we'll use for our outline var sp:Sprite = new Sprite(); var radius:int = 50; sp.graphics.beginFill(0x00FF00, 1); sp.graphics.drawCircle(0, 0, radius); sp.graphics.endFill(); sp.x = stage.stageWidth / 2; sp.y = stage.stageHeight / 2; // Create a bitmap data object to draw our vector data var bmd:BitmapData = new BitmapData(sp.width, sp.height, true, 0); // Use a transform matrix to translate the drawn clip so that none of its // pixels reside in negative space. The draw method will only draw starting // at 0,0 var mat:Matrix = new Matrix(1, 0, 0, 1, radius, radius); bmd.draw(sp, mat); // Pass the bitmap data to an actual bitmap var bmp:Bitmap = new Bitmap(bmd); // Add the bitmap to the stage addChild(bmp); // Grab all of the pixel data from the bitmap data object var pixels:Vector.<uint> = bmd.getVector(bmd.rect); // Setup a vector to hold our stroke points var points:Vector.<Point> = new Vector.<Point>; // Loop through all of the pixels of the bitmap data object and // create a point instance for each pixel location that isn't // transparent. var l:int = pixels.length; for(var i:int = 0; i < l; ++i) { // Check to see if the pixel is transparent if(pixels[i] != 0) { var pt:Point; // Check to see if the pixel is on the first or last // row. We'll grab everything from these rows to close the outline if(i <= bmp.width || i >= (bmp.width * bmp.height) - bmp.width) { pt = new Point(); pt.x = int(i % bmp.width); pt.y = int(i / bmp.width); points.push(pt); continue; } // Check to see if the current pixel is on either extreme edge if(int(i % bmp.width) == 0 || int(i % bmp.width) == bmp.width - 1) { pt = new Point(); pt.x = int(i % bmp.width); pt.y = int(i / bmp.width); points.push(pt); continue; } // Check to see if the previous or next pixel are transparent, // if so save the current one. if(i > 0 && i < bmp.width * bmp.height) { if(pixels[i - 1] == 0 || pixels[i + 1] == 0) { pt = new Point(); pt.x = int(i % bmp.width); pt.y = int(i / bmp.width); points.push(pt); } } } }

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  • Implementing 1 to n mapping for ORM c++

    - by karan
    I am writing a project where I need to implement a stripped down version of an ORM solution in C++. I am struck in implementing 1-n relationships for the same. For instance, if the following are the classes: class A { ... } class B { ... std::list<A> _a_list; ... } I have provided load/save methods for loading/saving to the db. Now, if I take the case of B and the following workflow: 1 entry from _a_list is removed 1 entry from _a_list is modified 1 entry is added to _a_list Now, I need to update the db using something like "b.save()". So, what would be the best way to save the changes, i.e, identify the additions, deletions and updates to _a_list.

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  • PHP Doxygen Collaboration Diagrams

    - by Shabbyrobe
    I've started playing around with doxygen to generate documentation from my PHP code. I notice there are two diagrams in the generated output - inheritance and collaboration. I know about the inheritance one, but the collaboration one has piqued my interest since reading the manual: If the COLLABORATION_GRAPH and HAVE_DOT tags are set to YES then doxygen will generate a graph for each documented class showing the direct and indirect implementation dependencies (inheritance, containment, and class references variables) of the class with other documented classes. The impression I get from that description is that composition relationships should be represented by the collaboration diagram as well, but it always seems to just be identical to the inheritance one. Is there something I can do to hint to Doxygen the things I would like to appear in this diagram? Does it just not work with PHP?

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  • Rails ActiveRecord- has_many through and belongs_to a related model

    - by Nick
    I have 3 models sites, user_favorites and users. Relevant relationships: class Site < ActiveRecord::Base has_many :users, :through => :user_favorites class UserFavorite < ActiveRecord::Base belongs_to :user, :counter_cache => true belongs_to :site end class User < ActiveRecord:Base has_many :user_favorites has_many :sites, :through => :user_favorites All of that works just fine. I'd like to add a new attribute to the Site model to indicate which user created it. I don't believe this constitutes a has_and_belongs_to_many scenario. A site has many users through user_favorites but I want it to belong to a single user reflecting the owner/creator. I'm wondering what the ORM best practice is for this. SQL wise I'd just use different joins depending on what I was trying to query with a created_by FK in Site. Sorry if I'm missing something basic here. Thanks

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  • Drupal : Custom views filter

    - by Joseph
    Hi, First thing I would say is that I am a Drupal newbie. So, I would appreciate your answer in a detailed step by step process. I am using Drupal 6 and location module. There are two main content types - user profile (using content profile module) and event content type. Both have one field for location. Now, lets suppose in his profile, user is selecting city as Toronto and province as Ontario. And some events have been added for Toronto city. I need one Views, which will display events from user city. So, if user is from Vancouver, and they click on "my city events", they will see list of events from their city. Someone told me that I can achieve this using arguments/ relationships, but I don't know how to do that. Can someone please help me out? I am not good at PHP either :(

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  • How to transform html anchor <a> to WordML

    - by Monomachus
    Hi, I need to transform an anchor tag to WordML without using relationships. Is it possible? I found the w: anchor property but seems it refers only to internal document anchors and not to links or URLs. <w:hyperlink w:anchor="chapter3"> <w:r> <w:t>Go to Chapter Three</w:t> </w:r> </w:hyperlink> So it would be great if something similar would be possible to do without making an Id in relationship document and than referring this id from w:hyperlink. Anyone knows something like that?

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  • how use graphvis in C# application?

    - by ghasedak -
    i have a dot format file and i download graphvis for windows now how can i use graphvis to show a graph in my c# application? using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using VDS.RDF; using VDS.RDF.Parsing; using VDS.RDF.Query; using System.IO; using System.Windows; using System.Runtime.InteropServices; using VDS.RDF.Writing; using System.Diagnostics; namespace WindowsFormsApplication2 { public partial class first : Form { Graph g = new Graph(); string s1 = null; /**************************************DATA********************************************/ public first() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { Stream myStream = null; var parser = new Notation3Parser(); var graph = new Graph(); OpenFileDialog openFileDialog1 = new OpenFileDialog(); openFileDialog1.Filter = "RDF files (*.n3)|*.n3"; openFileDialog1.FilterIndex = 1; openFileDialog1.RestoreDirectory = true; openFileDialog1.Multiselect = false; if (openFileDialog1.ShowDialog() == DialogResult.OK) { try { if ((myStream = openFileDialog1.OpenFile()) != null) { using (myStream) { string s = openFileDialog1.FileName.ToString(); string w= Directory.GetCurrentDirectory().ToString(); string Fname = openFileDialog1.SafeFileName.ToString(); File.Copy(s,Path.Combine(w,Fname),true); // Insert code to read the stream here. Win32.AllocConsole(); s1 = Path.Combine(w, Fname); insertNodeButton.Visible = true; delBut.Visible = true; simi.Visible = true; showNodes showNodes1 = new showNodes(s1); g = showNodes1.returngraph(); Console.Read(); Win32.FreeConsole(); // g.SaveToFile("firstfile.n3"); this.Show(); } } } catch (Exception ex) { MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message); } } GraphVizWriter hi = new GraphVizWriter(); hi.Save(g, "c:\\ahmad.dot"); } private void button2_Click(object sender, EventArgs e) { string strCmdLine = Application.StartupPath + "\\Tools\\rdfEditor.exe"; //string strCmdLine = "DIR"; MessageBox.Show(strCmdLine); System.Diagnostics.Process process1; process1 = new System.Diagnostics.Process(); //Do not receive an event when the process exits. process1.EnableRaisingEvents = false; //The "/C" Tells Windows to Run The Command then Terminate System.Diagnostics.Process.Start(strCmdLine); process1.Close(); } private void Form1_Load(object sender, EventArgs e) { } private void insertNodeButton_Click(object sender, EventArgs e) { //Graph parentvalue = this.g; //String parentvalueadress = this.s1; addTriple a1 = new addTriple(); a1.G = g; a1.BringToFront(); a1.ShowDialog(); g = a1.G; g.SaveToFile("c:\\Hi.n3"); } this is my code i want to visul saly dot file format to show a graph with graphvis

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  • Zero KB SQLite File created by Core Data on application start up

    - by Tots
    I'm developing an iPhone application using Core Data. I had everything working and had to make an adjustment to the database schema and change the relationships through the xcdatamodel file. I deleted the my project's sqlite file in Library/Application Support/iPhone Simulator/3.1.3//Documents. Build and run the application, it creates the sqlite file, but its empty with a file size of 0 KB. At a minimum the table information should be in there. There are no errors/warning in the console. Anyone have an idea what is wrong?

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  • SaaS Multi-tenancy Applications: How is data import/export/backup being implemented?

    - by Mark Redman
    How are applications providing import / export (or backups) of data in SaaS based multi-tenancy applications, particularly single database designs? Imports: Keeping things simple I think basic imports are useful, ie CSV to a spec (or a way of providing a mapping between CSV columns and fields in the database. Exports: In single database designs I have seen XML exports and HTML (basic sitse generated) exports of data? I would assume that XML is a better option? How does one cater for relational data? Would you reference various things within XML and provide documentation of the relationships or let users figurethis out? Are vendors providing an export/backup that can be imported back in/restored? Your comments appreciated.

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  • Assign values from same table

    - by Reddy S R
    I have a database table with parent child relationships between different rows. 1 parent can have any number of children. Children do not have children. I want to copy 'Message' from 'Parent Category' to child categories. CategoryID Name Value Message ParentID DeptId 1 Books 9 Specials 1 2 Music 7 1 3 Paperback 25 1 1 4 PDFs 26 1 2 5 CDs 35 2 1 If that was sample data, Paperback should have Specials as it's Message after the query is run. I have gotten the child rows (the query runs very slow, don't know why), but how do I get the data and assign it to appropriate child rows? --@DeptId = 1 select * from Categories where ParentID in( select CategoryID from Categories where DeptID = @DeptId ) I would like to see a solution that would not use cursors. Thanks

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  • How to handle customers with multiple addresses in CakePHP

    - by Ryan
    I'm putting together a system to track customer orders. Each order will have three addresses; a Main contact address, a billing address and a shipping address. I do not want to have columns in my orders table for the three addresses, I'd like to reference them from a separate table and have some way to enumerate the entry so I can determine if the addressing is main, shipping or billing. Does it make sense to create a column in the address table for AddressType and enumerate that or create another table - AddressTypes - that defines the address enumeration and link to that table? I have found other questions that touch on this topic and that is where I've taken my model. The problem I'm having is taking that into the cakePHP convention. I've been struggling to internalize the direction OneToMany relationships are formed - the way the documentation states feels backwards to me. Any help would be appreciated, Thanks!

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  • What's the best-practice way to update an Adapter's underlying data?

    - by skyler
    I'm running into an IllegalStateException updating an underlying List to an Adapter (might be an ArrayAdapter or an extension of BaseAdapter, I don't remember). I do not have or remember the text of the exception at the moment, but it says something to the effect of the List's content changing without the Adapter having been notified of the change. This List /may/ be updated from another thread other than the UI thread (main). After I update this list (adding an item), I call notifyDataSetChanged. The issue seems to be that the Adapter, or ListView attached to the Adapter attempts to update itself before this method is invoked. When this happens, the IllegalStateException is thrown. If I set the ListView's visibility to GONE before the update, then VISIBLE again, no error occurs. But this isn't always practical. I read somewhere that you cannot modify the underlying this from another thread--this would seem to limit an MVC pattern, as with this particular List, I want to add items from different threads. I assumed that as long as I called notifyDataSetChanged() I'd be safe--that the Adapter didn't revisit the underlying List until this method was invoked but this doesn't seem to be the case. I suppose what I'm asking is, can it be safe to update the underlying List from threads other than the UI? Additionally, if I want to modify the data within an Adapter, do I modify the underlying List or the Adapter itself (via its add(), etc. methods). Modifying the data through the Adapter seems wrong. I came across a thread on another site from someone who seems to be having a similar problem to mine: http://osdir.com/ml/Android-Developers/2010-04/msg01199.html (this is from where I grabbed the Visibility.GONE and .VISIBLE idea). To give you a better idea of my particular problem, I'll describe a bit of how my List, Adapter, etc. are set up. I've an object named Queue that contains a LinkedList. Queue extends Observable, and when things are added to its internal list through its methods, I call setChanged() and notifyListeners(). This Queue object can have items added or removed from any number of threads. I have a single "queue view" Activity that contains an Adapter. This Activity, in its onCreate() method, registers an Observer listener to my Queue object. In the Observer's update() method I call notifyDataSetChanged() on the Adapter. I added a lot of log output and determined that when this IllegalStateExcption occurs that my Observer callback was never invoked. So it's as if the Adapter noticed the List's change before the Observer had a chance to notify its Observers, and call my method to notify the Adapter that the contents had changed. So I suppose what I'm asking is, is this a good way to rig-up an Adapter? Is this a problem because I'm updating the Adapter's contents from a thread other than the UI thread? If this is the case, I may have a solution in mind (give the Queue object a Handler to the UI thread when it's created, and make all List modifications using that Handler, but this seems improper). I realize that this is a very open-ended post, but I'm a bit lost on this and would appreciate any comments on what I've written.

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  • SQL aggregation query, grouping by entries in junction table

    - by cm007
    I have TableA in a many-to-many relationship with TableC via TableB. That is, TableA TableB TableC id | val fkeyA | fkeyC id | data I wish the do select sum(val) on TableA, grouping by the relationship(s) to TableC. Every entry in TableA has at least one relationship with TableC. For example, TableA 1 | 25 2 | 30 3 | 50 TableB 1 | 1 1 | 2 2 | 1 2 | 2 2 | 3 3 | 1 3 | 2 should output 75 30 since rows 1 and 3 in Table have the same relationships to TableC, but row 2 in TableA has a different relationship to TableC. How can I write a SQL query for this?

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  • Securing files on IPhone

    - by clearbrian
    Hi Is there a way to decompile the binary from an IPhone app. I jailbroke my IPhone and was surprised to find other app's dbs wide open to be copied. So I exported my most important table and hardcoded it into code. Instead of loading table into array from a db I just generated code to fill the array and kept only the most basic DB info so relationships still work. Took a while but now works fine. I was just wondering am I safe, could someone decompile the binary for the app easily and extract the data. In Java its easy to decompile *.class files though thats bytecode where I presume iphone apps are more low level. I know IPhone sdk 4 can mark files as secure. Anyone know can this be overridden by jailbreaks or is this an unix lock?

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  • Process for beginning a Ruby on Rails project

    - by Daniel Beardsley
    I'm about to begin a Ruby on Rails project and I'd love to hear how others go through the process of starting an application design. I have quite a bit of experience with RoR, but don't have that many starting from scratch with only a vision experiences and would appreciate the wisdom of others who've been there. I'm looking for an order of events, reasons for the order, and maybe why each part is important. I can think of a few starting points, but I'm not sure where it's best to begin Model design and relationships (entities, how they relate, and their attributes) Think of user use-cases (or story-boards) and implement the minimum to get these done Create Model unit-tests then create the necessary migrations and AR models to get the tests to pass Hack out the most basic version of the simplest part of your application and go from there Start with a template for a rails app (like http://github.com/thoughtbot/suspenders) Do the boring gruntwork first (User auth, session management, ...) ...

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  • Minifying CSS, JS, and HTML - together

    - by Radu
    Minifying JS and CSS is quite common. The benefits of minifying JS are much greater that those seen with CSS because with CSS you can't rename elements - and same goes for HTML. But what if all 3 were minified together so that the benefits of using shorter names can be brought to CSS and HTML? That is, instead of minifying without any regard to the relationships between the 3, these could be preserved and made simpler. I imagine that the implementation could be quite difficult but if it were possible, do you think it would provide a significant advantage over traditional minification?

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  • MSSQL: Primary Key Schema Largely Guid but Sometimes Integer Types...

    - by Code Sherpa
    OK, this may be a silly question but... I have inherited a project and am tasked with going over the primary key relationships. The project largely uses Guids. I say "largely" because there are examples where tables use integral types to reflect enumerations. For example, dbo.MessageFolder has MessageFolderId of type int to reflect public emum MessageFolderTypes { inbox = 1, sent = 2, trash = 3, etc... } This happens a lot. There are tables with primary keys of type int which is unavoidable because of their reliance on enumerations and tables with primary keys of type Guid which reflect the primary key choice on the part of the previous programmer. Should I care that the PK schema is spotty like this? It doesn't feel right but does it really matter? If this could create a problem, how do I get around it (I really can't move all PKs to type int without serious legwork and I have never heard of enumerations that have guid values)? Thanks.

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  • How can I make the storage of C++ lambda objects more efficient?

    - by Peter Ruderman
    I've been thinking about storing C++ lambda's lately. The standard advice you see on the Internet is to store the lambda in a std::function object. However, none of this advice ever considers the storage implications. It occurred to me that there must be some seriously black voodoo going on behind the scenes to make this work. Consider the following class that stores an integer value: class Simple { public: Simple( int value ) { puts( "Constructing simple!" ); this->value = value; } Simple( const Simple& rhs ) { puts( "Copying simple!" ); this->value = rhs.value; } Simple( Simple&& rhs ) { puts( "Moving simple!" ); this->value = rhs.value; } ~Simple() { puts( "Destroying simple!" ); } int Get() const { return this->value; } private: int value; }; Now, consider this simple program: int main() { Simple test( 5 ); std::function<int ()> f = [test] () { return test.Get(); }; printf( "%d\n", f() ); } This is the output I would hope to see from this program: Constructing simple! Copying simple! Moving simple! Destroying simple! 5 Destroying simple! Destroying simple! First, we create the value test. We create a local copy on the stack for the temporary lambda object. We then move the temporary lambda object into memory allocated by std::function. We destroy the temporary lambda. We print our output. We destroy the std::function. And finally, we destroy the test object. Needless to say, this is not what I see. When I compile this on Visual C++ 2010 (release or debug mode), I get this output: Constructing simple! Copying simple! Copying simple! Copying simple! Copying simple! Destroying simple! Destroying simple! Destroying simple! 5 Destroying simple! Destroying simple! Holy crap that's inefficient! Not only did the compiler fail to use my move constructor, but it generated and destroyed two apparently superfluous copies of the lambda during the assignment. So, here finally are the questions: (1) Is all this copying really necessary? (2) Is there some way to coerce the compiler into generating better code? Thanks for reading!

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  • Multiple Table Joins to Improve Performance?

    - by EdenMachine
    If I have a table structure like this: Transaction [TransID, ...] Document [DocID, TransID, ...] Signer [SignerID, ...] Signature [SigID, DocID, SignerID, ...] And the business logic is like this: Transactions can have multiple documents Documents can have multiple signatures And the same signer can have multiple signatures in multiple documents within the same transaction So, now to my actual question: If I wanted to find all the documents in a particular transaction, would it be better, performance-wise, if I also stored the TransID and the DocID in the Signer table as well so I have smaller joins. Otherwise, I'd have to join through the Signature Document Transaction Documents to get all the documents in the transaction for that signer. I think it's really messy to have that many relationships in the Signer table though and it doesn't seem "correct" to do it that way (also seems like an update nightmare) but I can see that it might be better performance for direct joins. Thoughts? TIA!

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  • How to generalize a method call in Java (to avoid code duplication)

    - by dln385
    I have a process that needs to call a method and return its value. However, there are several different methods that this process may need to call, depending on the situation. If I could pass the method and its arguments to the process (like in Python), then this would be no problem. However, I don't know of any way to do this in Java. Here's a concrete example. (This example uses Apache ZooKeeper, but you don't need to know anything about ZooKeeper to understand the example.) The ZooKeeper object has several methods that will fail if the network goes down. In this case, I always want to retry the method. To make this easy, I made a "BetterZooKeeper" class that inherits the ZooKeeper class, and all of its methods automatically retry on failure. This is what the code looked like: public class BetterZooKeeper extends ZooKeeper { private void waitForReconnect() { // logic } @Override public Stat exists(String path, Watcher watcher) { while (true) { try { return super.exists(path, watcher); } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } @Override public byte[] getData(String path, boolean watch, Stat stat) { while (true) { try { return super.getData(path, watch, stat); } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } @Override public void delete(String path, int version) { while (true) { try { super.delete(path, version); return; } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } } (In the actual program there is much more logic and many more methods that I took out of the example for simplicity.) We can see that I'm using the same retry logic, but the arguments, method call, and return type are all different for each of the methods. Here's what I did to eliminate the duplication of code: public class BetterZooKeeper extends ZooKeeper { private void waitForReconnect() { // logic } @Override public Stat exists(final String path, final Watcher watcher) { return new RetryableZooKeeperAction<Stat>() { @Override public Stat action() { return BetterZooKeeper.super.exists(path, watcher); } }.run(); } @Override public byte[] getData(final String path, final boolean watch, final Stat stat) { return new RetryableZooKeeperAction<byte[]>() { @Override public byte[] action() { return BetterZooKeeper.super.getData(path, watch, stat); } }.run(); } @Override public void delete(final String path, final int version) { new RetryableZooKeeperAction<Object>() { @Override public Object action() { BetterZooKeeper.super.delete(path, version); return null; } }.run(); return; } private abstract class RetryableZooKeeperAction<T> { public abstract T action(); public final T run() { while (true) { try { return action(); } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } } } The RetryableZooKeeperAction is parameterized with the return type of the function. The run() method holds the retry logic, and the action() method is a placeholder for whichever ZooKeeper method needs to be run. Each of the public methods of BetterZooKeeper instantiates an anonymous inner class that is a subclass of the RetryableZooKeeperAction inner class, and it overrides the action() method. The local variables are (strangely enough) implicitly passed to the action() method, which is possible because they are final. In the end, this approach does work and it does eliminate the duplication of the retry logic. However, it has two major drawbacks: (1) it creates a new object every time a method is called, and (2) it's ugly and hardly readable. Also I had to workaround the 'delete' method which has a void return value. So, here is my question: is there a better way to do this in Java? This can't be a totally uncommon task, and other languages (like Python) make it easier by allowing methods to be passed. I suspect there might be a way to do this through reflection, but I haven't been able to wrap my head around it.

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  • Facebook user_id as MongoDB BSON ObjectId?

    - by MattDiPasquale
    I'm rebuilding Lovers on Facebook with Sinatra & Redis. I like Redis because it doesn't have the long (12-byte) BSON ObjectIds and I am storing sets of Facebook user_ids for each user. The sets are requests_sent, requests_received, & relationships, and they all contain Facebook user ids. I'm thinking of switching to MongoDB because I want to use it's geospatial indexing. If I do, I'd want to use the FB user ids as the _id field because I want the sets to be small and I want the JSON responses to be small. But, is the BSON ObjectId better (more efficient for MongoDB) to use than just an integer (fb user_id)?

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  • Resources for learning how to better read code

    - by rsteckly
    Hi, I recently inherited a large codebase and am having to read it. The thing is, I've usually been the dev starting a project. As a result, I don't have a lot of experience reading code. My reaction to having to read a lot of code is, well, umm to rewrite it. But I need to bring myself up to speed quickly and build on top of an existing system. Do other people have techniques they've learned to absorb a code base? At this point, I'm just reading through the code. I've tried generating UML diagrams using UModel. They're so big they won't print cleanly and when I zoom in, I really do lose the perspective of seeing all the relationships. How have other people dealt with this problem?

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  • ruby on rails has_many through relationship

    - by BennyB
    Hi i'm having a little trouble with a has_many through relationship for my app and was hoping to find some help. So i've got Users & Lectures. Lectures are created by one user but then other users can then "join" the Lectures that have been created. Users have their own profile feed of the Lectures they have created & also have a feed of Lectures friends have created. This question however is not about creating a lecture but rather "Joining" a lecture that has been created already. I've created a "lecturerelationships" model & controller to handle this relationship between Lectures & the Users who have Joined (which i call "actives"). Users also then MUST "Exit" the Lecture (either by clicking "Exit" or navigating to one of the header navigation links). I'm grateful if anyone can work through some of this with me... I've got: Users.rb model Lectures.rb model Users_controller Lectures_controller then the following model lecturerelationship.rb class lecturerelationship < ActiveRecord::Base attr_accessible :active_id, :joinedlecture_id belongs_to :active, :class_name => "User" belongs_to :joinedlecture, :class_name => "Lecture" validates :active_id, :presence => true validates :joinedlecture_id, :presence => true end lecturerelationships_controller.rb class LecturerelationshipsController < ApplicationController before_filter :signed_in_user def create @lecture = Lecture.find(params[:lecturerelationship][:joinedlecture_id]) current_user.join!(@lecture) redirect_to @lecture end def destroy @lecture = Lecturerelationship.find(params[:id]).joinedlecture current_user.exit!(@user) redirect_to @user end end Lectures that have been created (by friends) show up on a users feed in the following file _activity_item.html.erb <li id="<%= activity_item.id %>"> <%= link_to gravatar_for(activity_item.user, :size => 200), activity_item.user %><br clear="all"> <%= render :partial => 'shared/join', :locals => {:activity_item => activity_item} %> <span class="title"><%= link_to activity_item.title, lecture_url(activity_item) %></span><br clear="all"> <span class="user"> Joined by <%= link_to activity_item.user.name, activity_item.user %> </span><br clear="all"> <span class="timestamp"> <%= time_ago_in_words(activity_item.created_at) %> ago. </span> <% if current_user?(activity_item.user) %> <%= link_to "delete", activity_item, :method => :delete, :confirm => "Are you sure?", :title => activity_item.content %> <% end %> </li> Then you see I link to the the 'shared/join' partial above which can be seen in the file below _join.html.erb <%= form_for(current_user.lecturerelationships.build(:joinedlecture_id => activity_item.id)) do |f| %> <div> <%= f.hidden_field :joinedlecture_id %> </div> <%= f.submit "Join", :class => "btn btn-large btn-info" %> <% end %> Some more files that might be needed: config/routes.rb SampleApp::Application.routes.draw do resources :users do member do get :following, :followers, :joined_lectures end end resources :sessions, :only => [:new, :create, :destroy] resources :lectures, :only => [:create, :destroy, :show] resources :relationships, :only => [:create, :destroy] #for users following each other resources :lecturerelationships, :only => [:create, :destroy] #users joining existing lectures So what happens is the lecture comes in my activity_feed with a Join button option at the bottom...which should create a lecturerelationship of an "active" & "joinedlecture" (which obviously are supposed to be coming from the user & lecture classes. But the error i get when i click the join button is as follows: ActiveRecord::StatementInvalid in LecturerelationshipsController#create SQLite3::ConstraintException: constraint failed: INSERT INTO "lecturerelationships" ("active_id", "created_at", "joinedlecture_id", "updated_at") VALUES (?, ?, ?, ?) Also i've included my user model (seems the error is referring to it) user.rb class User < ActiveRecord::Base attr_accessible :email, :name, :password, :password_confirmation has_secure_password has_many :lectures, :dependent => :destroy has_many :lecturerelationships, :foreign_key => "active_id", :dependent => :destroy has_many :joined_lectures, :through => :lecturerelationships, :source => :joinedlecture before_save { |user| user.email = email.downcase } before_save :create_remember_token validates :name, :presence => true, :length => { :maximum => 50 } VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i validates :email, :presence => true, :format => { :with => VALID_EMAIL_REGEX }, :uniqueness => { :case_sensitive => false } validates :password, :presence => true, :length => { :minimum => 6 } validates :password_confirmation, :presence => true def activity # This feed is for "My Activity" - basically lectures i've started Lecture.where("user_id = ?", id) end def friendactivity Lecture.from_users_followed_by(self) end # lECTURE TO USER (JOINING) RELATIONSHIPS def joined?(selected_lecture) lecturerelationships.find_by_joinedlecture_id(selected_lecture.id) end def join!(selected_lecture) lecturerelationships.create!(:joinedlecture_id => selected_lecture.id) end def exit!(selected_lecture) lecturerelationships.find_by_joinedlecture_id(selected_lecture.id).destroy end end Thanks for any and all help - i'll be on here for a while so as mentioned i'd GREATLY appreciate someone who may have the time to work through my issues with me...

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