Search Results

Search found 11051 results on 443 pages for 'bind variables'.

Page 134/443 | < Previous Page | 130 131 132 133 134 135 136 137 138 139 140 141  | Next Page >

• ODI 11g - Dynamic and Flexible Code Generation

  - by David Allan

  ODI supports conditional branching at execution time in its code generation framework. This is a little used, little known, but very powerful capability - this let's one piece of template code behave dynamically based on a runtime variable's value for example. Generally knowledge module's are free of any variable dependency. Using variable's within a knowledge module for this kind of dynamic capability is a valid use case - definitely in the highly specialized area. The example I will illustrate is much simpler - how to define a filter (based on mapping here) that may or may not be included depending on whether at runtime a certain value is defined for a variable. I define a variable V_COND, if I set this variable's value to 1, then I will include the filter condition 'EMP.SAL > 1' otherwise I will just use '1=1' as the filter condition. I use ODIs substitution tags using a special tag '<$' which is processed just prior to execution in the runtime code - so this code is included in the ODI scenario code and it is processed after variables are substituted (unlike the '<?' tag).  So the lines below are not equal ... <$ if ( "#V_COND".equals("1")  ) { $> EMP.SAL > 1 <$ } else { $> 1 = 1 <$ } $> <? if ( "#V_COND".equals("1")  ) { ?> EMP.SAL > 1 <? } else { ?> 1 = 1 <? } ?> When the <? code is evaluated the code is executed without variable substitution - so we do not get the desired semantics, must use the <$ code. You can see the jython (java) code in red is the conditional if statement that drives whether the 'EMP.SAL > 1' or '1=1' is included in the generated code. For this illustration you need at least the ODI 11.1.1.6 release - with the vanilla 11.1.1.5 release it didn't work for me (may be patches?). As I mentioned, normally KMs don't have dependencies on variables - since any users must then have these variables defined etc. but it does afford a lot of runtime flexibility if such capabilities are required - something to keep in mind, definitely.

  Read the article

• Renderbuffer to GLSL shader?

  - by Dan

  I have a software that performs volume rendering through a raycasting approach. The actual raycasting shader writes the raycasted volume depth into a framebuffer object, through gl_FragDepth, that I bind before calling the shader. The problem I have is that I would like to use this depth in another shader that I call later on. I figured out that the only way to do that is to bind the framebuffer once the raycasting has finished, read the depthmap through something like glReadPixels(0, 0, m_winSize.x , m_winSize.y, GL_DEPTH_COMPONENT, GL_FLOAT, pixels); and write it to a 2D texture as usual glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT24, m_winSize.x, m_winSize.y, 0, GL_DEPTH_COMPONENT, GL_FLOAT, pixels) and then pass this 2D texture that contains a simple depth map to the other shader. However, I am not entirely sure that what I do is the proper way to do this. Is there anyway to pass the framebuffer that I fill up in my raycasting shader to the other shader?

  Read the article

• Single IBAction for multiple UIButtons versus single IBAction for single UIButton

  - by Miraaj

  While using story-board there are two different approaches which my team mates follow: Approach 1: To bind unique action with each button, ie: Done button - binded to - doneButtonAction Cancel button - binded to - cancelButtonAction OR Approach 2: To bind single action to multiple buttons, ie: Done button - binded to - commonButtonAction Cancel button - binded to - commonButtonAction Then in commonButtonAction they prefer to use switch case like this: - (IBAction)commonButtonAction:(id)sender { UIButton *button = (UIButton *)sender; switch (button.tag) { case 201: // done button [self doneButtonAction:sender]; break; case 202: // cancel button [self cancelButtonAction:sender]; break; default: break; } } - (void)cancelButtonAction:(id)sender { // no interesting stuff, simple dismiss of view :-( } - (void)doneButtonAction:(id)sender { // some interesting stuff ;-) } Reasoning which they give to follow approach 2 is - in each view controller during code walk through anyone can easily identify where to find code related to button actions. While others discard this idea because they say that adding an extra switch case is unnecessary and is not a common practice. What are your views?

  Read the article

• Introduction to LinqPad Driver for StreamInsight 2.1

  - by Roman Schindlauer

  We are announcing the availability of the LinqPad driver for StreamInsight 2.1. The purpose of this blog post is to offer a quick introduction into the new features that we added to the StreamInsight LinqPad driver. We’ll show you how to connect to a remote server, how to inspect the entities present of that server, how to compose on top of them and how to manage their lifetime. Installing the driver Info on how to install the driver can be found in an earlier blog post here. Establishing connections As you click on the “Add Connection” link in the left pane you will notice that now it’s possible to build the data context automatically. The new driver appears as an option in the upper list, and if you pick it you will open a connection dialog that lets you connect to a remote StreamInsight server. The connection dialog lets you specify the address of the remote server. You will notice that it’s possible to pick up the binding information from the configuration file of the LinqPad application (which is normally in the same folder as LinqPad.exe and is called LinqPad.exe.config). In order for the context to be generated you need to pick an application from the server. The control is editable hence you can create a new application if you don’t want to make changes to an existing application. If you choose a new application name you will be prompted for confirmation before this gets created. Once you click OK the connection is created and you can start issuing queries against the remote server. If there’s any connectivity error the connection is marked with a red X and you can see the error message informing you what went wrong (i.e., the remote server could not be reached etc.). The context for remote servers Let’s take a look at what happens after we are connected successfully. Every LinqPad query runs inside a context – think of it as a class that wraps all the code that you’re writing. If you’re connecting to a live server the context will contain the following: The application object itself. All entities present in this application (sources, sinks, subjects and processes). The picture below shows a snapshot of the left pane of LinqPad after a successful connection. Every entity on the server has a different icon which will allow users to figure out its purpose. You will also notice that some entities have a string in parentheses following the name. It should be interpreted as such: the first name is the name of the property of the context class and the second name is the name of the entity as it exists on the server. Not all valid entity names are valid identifier names so in cases where we had to make a transformation you see both. Note also that as you hover over the entities you get IntelliSense with their types – more on that later. Remoting is not supported As you play with the entities exposed by the context you will notice that you can’t read and write directly to/from them. If for instance you’re trying to dump the content of an entity you will get an error message telling you that in the current version remoting is not supported. This is because the entity lives on the remote server and dumping its content means reading the events produced by this entity into the local process. ObservableSource.Dump(); Will yield the following error: Reading from a remote 'System.Reactive.Linq.IQbservable`1[System.Int32]' is not supported. Use the 'Microsoft.ComplexEventProcessing.Linq.RemoteProvider.Bind' method to read from the source using a remote observer. This basically tells you that you can call the Bind() method to direct the output of this source to a sink that has to be defined on the remote machine as well. You can’t bring the results to the LinqPad window unless you write code specifically for that. Compose queries You may ask – what's the purpose of all that? After all the same information is present in the EventFlowDebugger, why bother with showing it in LinqPad? First of all, What gets exposed in LinqPad is not what you see in the debugger. In LinqPad we have a property on the context class for every entity that lives on the server. Because LinqPad offers IntelliSense we in fact have much more information about the entity, and more importantly we can compose with that entity very easily. For example, let’s say that this code creates an entity: using (var server = Server.Connect(...)) {     var a = server.CreateApplication("WhiteFish");     var src = a         .DefineObservable<int>(() => Observable.Range(0, 3))         .Deploy("ObservableSource"); If later we want to compose with the source we have to fetch it and then we can bind something to     a.GetObservable<int>("ObservableSource)").Bind(... This means that we had to know a bunch of things about this: that it’s a source, that it’s an observable, it produces a result with payload Int32 and it’s named “ObservableSource”. Only the second and last bits of information are present in the debugger, by the way. As you type in the query window you see that all the entities are present, you get IntelliSense support for them and it’s much easier to make sense of what’s available. Let’s look at a scenario where composition is plausible. With the new programming model it’s possible to create “cold” sources that are parameterized. There was a way to accomplish that even in the previous version by passing parameters to the adapters, but this time it’s much more elegant because the expression declares what parameters are required. Say that we hover the mouse over the ThrottledSource source – we will see that its type is Func<int, int, IQbservable<int>> - this in effect means that we need to pass two int parameters before we can get a source that produces events, and the type for those events is int – in the particular case of my example I had the source produce a range of integers and the two parameters were the start and end of the range. So we see how a developer can create a source that is not running yet. Then someone else (e.g. an administrator) can pass whatever parameters appropriate and run the process. Proxy Types Here’s an interesting scenario – what if someone created a source on a server but they forgot to tell you what type they used. Worse yet, they might have used an anonymous type and even though they can refer to it by name you can’t figure out how to use that type. Let’s walk through an example that shows how you can compose against types you don’t need to have the definition of. This is how we can create a source that returns an anonymous type: Application.DefineObservable(() => Observable.Range(1, 10).Select(i => new { I = i })).Deploy("O1"); Now if we refresh the connection we can see the new source named O1 appear in the list. But what’s more important is that we now have a type to work with. So we can compose a query that refers to the anonymous type. var threshold = new StreamInsightDynamicDriver.TypeProxies.AnonymousType1_0<int>(5); var filter = from i in O1              where i > threshold              select i; filter.Deploy("O2"); You will notice that the anonymous type defined with this statement: new { I = i } can now be manipulated by a client that does not have access to it because the LinqPad driver has generated another type in its stead, named StreamInsightDynamicDriver.TypeProxies.AnonymousType1_0. This type has all the properties and fields of the type defined on the server, except in this case we can instantiate values and use it to compose more queries. It is worth noting that the same thing works for types that are not anonymous – the test is if the LinqPad driver can resolve the type or not. If it’s not possible then a new type will be generated that approximates the type that exists on the server. Control metadata In addition to composing processes on top of the existing entities we can do other useful things. We can delete them – nothing new here as we simply access the entities through the Entities collection of the application class. Here is where having their real name in parentheses comes handy. There’s another way to find out what’s behind a property – dump its expression. The first line in the output tells us what’s the name of the entity used to build this property in the context. Runtime information So let’s create a process to see what happens. We can bind a source to a sink and run the resulting process. If you right click on the connection you can refresh it and see the process present in the list of entities. Then you can drag the process to the query window and see that you can have access to process object in the Processes collection of the application. You can then manipulate the process (delete it, read its diagnostic view etc.). Regards, The StreamInsight Team

  Read the article

• Synchronization between game logic thread and rendering thread

  - by user782220

  How does one separate game logic and rendering? I know there seem to already be questions on here asking exactly that but the answers are not satisfactory to me. From what I understand so far the point of separating them into different threads is so that game logic can start running for the next tick immediately instead of waiting for the next vsync where rendering finally returns from the swapbuffer call its been blocking on. But specifically what data structures are used to prevent race conditions between the game logic thread and the rendering thread. Presumably the rendering thread needs access to various variables to figure out what to draw, but game logic could be updating these same variables. Is there a de facto standard technique for handling this problem. Maybe like copy the data needed by the rendering thread after every execution of the game logic. Whatever the solution is will the overhead of synchronization or whatever be less than just running everything single threaded?

  Read the article

• Is it appropriate for a class to only be a collection of information with no logic?

  - by qegal

  Say I have a class Person that has instance variables age, weight, and height, and another class Fruit that has instance variables sugarContent and texture. The Person class has no methods save setters and getters, while the Fruit class has both setters and getters and logic methods like calculateSweetness. Is the Fruit class the type of class that is better practice than the Person class. What I mean by this is that the Person class seems like it doesn't have much purpose; it exists solely to organize data, while the Fruit class organizes data and actually contains methods for logic.

  Read the article

• Difference between EJB Persist & Merge operation

  - by shantala.sankeshwar

  This article gives the difference between EJB Persist & Merge operations with scenarios.Use Case Description Users working on EJB persist & merge operations often have this question in mind " When merge can create new entity as well as modify existing entity,then why do we have 2 separate operations - persist & merge?" The reason is very simple.If we use merge operation to create new entity & if the entity exists then it does not throw any exception,but persist throws exception if the entity already exists.Merge should be used to modify the existing entity.The sql statement that gets executed on persist operation is insert statement.But in case of merge first select statement gets executed & then update sql statement gets executed.Scenario 1: Persist operation to create new Emp recordLet us suppose that we have a Java EE Web Application created with Entities from Emp table & have created session bean with data control. Drop Emp Object(Expand SessionEJBLocal->Constructors under Data Controls) as ADF Parameter form in jspx pageDrop persistEmp(Emp) as ADF CommandButton & provide #{bindings.EmpIterator.currentRow.dataProvider} as the value for emp parameter.Then run this page & provide values for Emp,click on 'persistEmp' button.New Emp record gets created.So when we execute persist operation only insert sql statement gets executed :INSERT INTO EMP (EMPNO, COMM, HIREDATE, ENAME, JOB, DEPTNO, SAL, MGR) VALUES (?, ?, ?, ?, ?, ?, ?, ?)    bind => [2, null, null, e2, null, 10, null, null]Scenario 2: Merge operation to modify existing Emp recordLet us suppose that we have a Java EE Web Application created with Entities from Emp table & have created session bean with data control.Drop empFindAll() Object as ADF form on jspx page.Drop mergeEmp(Emp) operation as commandButton & provide #{bindings.EmpIterator.currentRow.dataProvider} as the value for emp parameter.Then run this page & modify values for Emp record,click on 'mergeEmp' button.The respective Emp record gets modified.So when we execute merge operation select & update sql statements gets executed :SELECT EMPNO, COMM, HIREDATE, ENAME, JOB, DEPTNO, SAL, MGR FROM EMP WHERE (EMPNO = ?) bind => [7566]UPDATE EMP SET ENAME = ? WHERE (EMPNO = ?) bind => [KINGS, 7839]

  Read the article

• Compiz command plugin won't register keyboard shortcuts

  - by David Moles

  Per this discussion I've enabled the Compiz commands plugin in order to try to bind some keyboard shortcuts to wmctrl actions. CCSM captures my keystrokes just fine, but no matter what keystroke I try or what command I bind it to (everything from my original intention of binding Super-1, Super-2 etc. to wmctrl -o 0,0, wmctrl -o 2560,0, etc., to binding Ctrl-Alt-Shift-L to gnome-terminal). Basic compiz shortcuts for window switching and so on -- even custom ones -- seem to work fine, but the command plugin doesn't seem to be working at all. I also notice the following symptom: when I open the keyboard shortcut tab in CCSM, the keyboard shortcuts often at first appear blank, though if you click on the blank button, the correct value is still there. Also possibly related, I've noticed that gnome-terminal doesn't seem to notice the Super key, though other apps (e.g. CCSM, Emacs) register it fine. Anyway, it seems like something's eating my keystrokes. Any ideas?

  Read the article

• Calculating instantaneous speed and acceleration for a simple Car software model

  - by Dylan

  I am trying to model a speedometer and tachometer for a simple software model of a car dashboard. I want this to be relatively simple, so for my purposes I won't likely simulate variables such as drag (or, assume that drag is a constant). But I would like to know the general formulas for: 1) Calculating the RPM, depending on a position of a graphical slider representing the accelerator. 2) Using this information to find the instantaneous speed (or, magnitude of instantaneous velocity?). I am not sure, in the case of 2), what other independent variables I need to consider. Do I need to consider the frequency of rotation of the wheels (assuming a fixed radius), in addition to the RPM? If anyone can give me a rough explanation plus relevant formulas, or alternatively direct me to other trusted resources online (I have had a hard time sifting through info and determining the accuracy), it would be much appreciated.

  Read the article

• problem using pydoc in python

  - by rohanag

  I'm using pydoc in python 2.7.3 to generate documentation for a file called PreProcessingAPI.py which contains a class called PreProcessingAPI In PreProcessingAPI.py, I have the following import in the beginning of the file: from __future__ import division from re import * from nltk.stem import porter The problem is, in the documentation generated by pydoc, nltk.stem.porter is shown as a Module. There is also a DATA heading with all sorts of variables I do not know about. Is there a way to avoid these variables and avoid showing nltk.stem.porter in the modules? I'm running the following command to generate documentation python pydoc.py -w PreProcessingAPI.py I've put the file pydoc.py in the directory containing my file. Here is the file generated: https://www.dropbox.com/s/4rb6ut99o25mwly/PreProcessingAPI.html

  Read the article

• Multiple values for a specif custom variable in Google Analytics

  - by Nicola Pacini

  we're trying to get rid of a this question : would it be possible to setup more than one value in a custom variable in Google Analytics, at page level ? Eg: _gaq.push(['_setCustomVar',3,'Tag','Custom Variables',3]); We'd like to track most popular tags on a web site who publishes news, articles and stuff. Contents are categorized (each content belongs to one category) and tagged (1 or more tags for each article). So, we'd like to apply this code: _gaq.push(['_setCustomVar',3,'Tag','Custom Variables',3]); _gaq.push(['_setCustomVar',3,'Tag','Google Analytics',3]); in a page that shows an article with these two tags assigned. What do you think? Honestly I didn't find anything in documentation from Google and some other example sites. Many thanks! Nicola

  Read the article

• Is Java easy decompilation a factor worth considering

  - by Sandra G

  We are considering the programming language for a desktop application with extended GUI use (tables, windows) and heavy database use. We considered Java for use however the fact that it can be decompiled back very easily into source code is holding us back. There are of course many obfuscators available however they are just that: obfuscators. The only obfuscation worth doing we got was stripping function and variables names into meaningless letters and numbers so that at least stealing code and renaming it back into something meaningful is too much work and we are 100% sure it is not reversible back in any automated way. However as it concerns to protecting internals (like password hashes or sensible variables content) we found obfuscators really lacking. Is there any way to make Java applications as hard to decode as .exe counterparts? And is it a factor to consider when deciding whether to develop in Java a desktop application?

  Read the article

• Javascript Closures - What are the negatives?

  - by vol7ron

  Question: There seem to be many benefits to Closures, but what are the negatives (memory leakage? obfuscation problems? bandwidth increasage?)? Additionally, is my understanding of Closures correct? Finally, once closures are created, can they be destroyed? I've been reading a little bit about Javascript Closures. I hope someone a little more knowledgeable will guide my assertions, correcting me where wrong. Benefits of Closures: Encapsulate the variables to a local scope, by using an internal function. The anonymity of the function is insignificant. What I've found helpful is to do some basic testing, regarding local/global scope: <script type="text/javascript"> var global_text = ""; var global_count = 0; var global_num1 = 10; var global_num2 = 20; var global_num3 = 30; function outerFunc() { var local_count = local_count || 0; alert("global_num1: " + global_num1); // global_num1: undefined var global_num1 = global_num1 || 0; alert("global_num1: " + global_num1); // global_num1: 0 alert("global_num2: " + global_num2); // global_num2: 20 global_num2 = global_num2 || 0; // (notice) no definition with 'var' alert("global_num2: " + global_num2); // global_num2: 20 global_num2 = 0; alert("local_count: " + local_count); // local_count: 0 function output() { global_num3++; alert("local_count: " + local_count + "\n" + "global_count: " + global_count + "\n" + "global_text: " + global_text ); local_count++; } local_count++; global_count++; return output; } var myFunc = outerFunc(); myFunc(); /* Outputs: ********************** * local_count: 1 * global_count: 1 * global_text: **********************/ global_text = "global"; myFunc(); /* Outputs: ********************** * local_count: 2 * global_count: 1 * global_text: global **********************/ var local_count = 100; myFunc(); /* Outputs: ********************** * local_count: 3 * global_count: 1 * global_text: global **********************/ alert("global_num1: " + global_num1); // global_num1: 10 alert("global_num2: " + global_num2); // global_num2: 0 alert("global_num3: " + global_num3); // global_num3: 33 </script> Interesting things I took out of it: The alerts in outerFunc are only called once, which is when the outerFunc call is assigned to myFunc (myFunc = outerFunc()). This assignment seems to keep the outerFunc open, in what I would like to call a persistent state. Everytime myFunc is called, the return is executed. In this case, the return is the internal function. Something really interesting is the localization that occurs when defining local variables. Notice the difference in the first alert between global_num1 and global_num2, even before the variable is trying to be created, global_num1 is considered undefined because the 'var' was used to signify a local variable to that function. -- This has been talked about before, in the order of operation for the Javascript engine, it's just nice to see this put to work. Globals can still be used, but local variables will override them. Notice before the third myFunc call, a global variable called local_count is created, but it as no effect on the internal function, which has a variable that goes by the same name. Conversely, each function call has the ability to modify global variables, as noticed by global_var3. Post Thoughts: Even though the code is straightforward, it is cluttered by alerts for you guys, so you can plug and play. I know there are other examples of closures, many of which use anonymous functions in combination with looping structures, but I think this is good for a 101-starter course to see the effects. The one thing I'm concerned with is the negative impact closures will have on memory. Because it keeps the function environment open, it is also keeping those variables stored in memory, which may/may not have performance implications, especially regarding DOM traversals and garbage collection. I'm also not sure what kind of role this will play in terms of memory leakage and I'm not sure if the closure can be removed from memory by a simple "delete myFunc;." Hope this helps someone, vol7ron

  Read the article

• An Epic Question "How to call a method when the page loads"

  - by Arunkumar Ramamoorthy

  Quite often, there comes a question in OTN, with different subjects, all meaning "How to call a method when my ADF page loads?". More often, people tend to take the approach of ADF Phase Listener by overriding before/afterPhase methods.In this blog, we will go through different options in achieving it.1. Method Call Activity as default activity in Taskflow :If the application is built with taskflows, then this is the best suited approach to take. 1.a. Calling a Data Control Method :To call a Data Control method (ex: A method in AMImpl exposed as client interface), simply Drag and Drop the method as Default Method Call Activity, then draw a control flow case from the method to your page. Once after this, drop the taskflow as region in main page. When we run the main page, the Method Call Activity would be called first, and then the page will be rendered.1.b. Calling a Method in Backing Bean: To call a method in the backing bean before pageload, we can follow the similar approach as above. Instead of binding the Method Call Activity to an action/method binding in pagedef, we bind to the method. Insert a Method Call Activity (and make it as default) from the Component Palette. Double click on to select a method to bind. This approach can also be used, to perform some action in backing bean along with calling a method Data Control (just need to add bindings code in backing bean to execute DC method). 2. Using invokeAction Executable :If the application is built with pages and no taskflows are involved, then this option can be taken into consideration.In the page definition of the page, add an invokeAction Executable and bind it to the method needed to be executed. 3. Using combination of Server and Client Listeners : If the page does not have any page definition, then to call a method in backing bean, this approach can be taken. In this, a serverListener would be added at the document level, which would be calling the method in backing bean. Along with this, a clientListener would be added with "load" type (i.e will be triggered when the page loads), which would queue a serverEvent to trigger the method. 4. Using Page Phase Listener :This should be the last resort. Care should be taken when using this approach since the Phase Listener would be called for each request sent by the client.Zeeshan Baig's blog covers this scenario.

  Read the article

• An Epic Question "How to call a method when the page loads"

  - by Arunkumar Ramamoorthy

  Quite often, there comes a question in OTN, with different subjects, all meaning "How to call a method when my ADF page loads?". More often, people tend to take the approach of ADF Phase Listener by overriding before/afterPhase methods.In this blog, we will go through different options in achieving it.1. Method Call Activity as default activity in Taskflow :If the application is built with taskflows, then this is the best suited approach to take. 1.a. Calling a Data Control Method :To call a Data Control method (ex: A method in AMImpl exposed as client interface), simply Drag and Drop the method as Default Method Call Activity, then draw a control flow case from the method to your page. Once after this, drop the taskflow as region in main page. When we run the main page, the Method Call Activity would be called first, and then the page will be rendered.1.b. Calling a Method in Backing Bean: To call a method in the backing bean before pageload, we can follow the similar approach as above. Instead of binding the Method Call Activity to an action/method binding in pagedef, we bind to the method. Insert a Method Call Activity (and make it as default) from the Component Palette. Double click on to select a method to bind. This approach can also be used, to perform some action in backing bean along with calling a method Data Control (just need to add bindings code in backing bean to execute DC method). 2. Using invokeAction Executable :If the application is built with pages and no taskflows are involved, then this option can be taken into consideration.In the page definition of the page, add an invokeAction Executable and bind it to the method needed to be executed. 3. Using combination of Server and Client Listeners : If the page does not have any page definition, then to call a method in backing bean, this approach can be taken. In this, a serverListener would be added at the document level, which would be calling the method in backing bean. Along with this, a clientListener would be added with "load" type (i.e will be triggered when the page loads), which would queue a serverEvent to trigger the method. 4. Using Page Phase Listener :This should be the last resort. Care should be taken when using this approach since the Phase Listener would be called for each request sent by the client.Zeeshan Baig's blog covers this scenario.

  Read the article

• What is required for a scope in an injection framework?

  - by johncarl

  Working with libraries like Seam, Guice and Spring I have become accustomed to dealing with variables within a scope. These libraries give you a handful of scopes and allow you to define your own. This is a very handy pattern for dealing with variable lifecycles and dependency injection. I have been trying to identify where scoping is the proper solution, or where another solution is more appropriate (context variable, singleton, etc). I have found that if the scope lifecycle is not well defined it is very difficult and often failure prone to manage injections in this way. I have searched on this topic but have found little discussion on the pattern. Is there some good articles discussing where to use scoping and what are required/suggested prerequisites for scoping? I interested in both reference discussion or your view on what is required or suggested for a proper scope implementation. Keep in mind that I am referring to scoping as a general idea, this includes things like globally scoped singletons, request or session scoped web variable, conversation scopes, and others. Edit: Some simple background on custom scopes: Google Guice custom scope Some definitions relevant to above: “scoping” - A set of requirements that define what objects get injected at what time. A simple example of this is Thread scope, based on a ThreadLocal. This scope would inject a variable based on what thread instantiated the class. Here's an example of this: “context variable” - A repository passed from one object to another holding relevant variables. Much like scoping this is a more brute force way of accessing variables based on the calling code. Example: methodOne(Context context){ methodTwo(context); } methodTwo(Context context){ ... //same context as method one, if called from method one } “globally scoped singleton” - Following the singleton pattern, there is one object per application instance. This applies to scopes because there is a basic lifecycle to this object: there is only one of these objects instantiated. Here's an example of a JSR330 Singleton scoped object: @Singleton public void SingletonExample{ ... } usage: public class One { @Inject SingeltonExample example1; } public class Two { @Inject SingeltonExample example2; } After instantiation: one.example1 == two.example2 //true;

  Read the article

• How do I handle priority and propagation in an event system?

  - by Peeter

  Lets say I have a simple event system with the following syntax: object = new Object(); object.bind("my_trigger", function() { print "hello"; }); object.bind("my_trigger", function() { print "hello2"; }); object.trigger("my_trigger"); How could I make sure hello2 is printed out first (I do not want my code to depend on which order the events are binded). Ontop of that, how would I prevent my events from propagating (e.g. I want to stop every other event from being executed)

  Read the article

• stud ubuntu howto?

  - by Matt H

  I've just been looking at the stud init script as I thought perhaps I'm meant to create a stud.conf inside /etc/stud However, in looking through the init script it would apppear that it loads stud.conf variables into the current environment. This of course fails for some reason and you get a bunch of errors. Worse still, stud source code doesn't work with environment variables. Can someone tell me how you're actually meant to set up stud with init script as it would appear to be completely broken. Maybe I can just disable the init script and call stud from rc.local?

  Read the article

• Database Rebuild

  - by Robert May

  I promised I’d have a simpler mechanism for rebuilding the database.  Below is a complete MSBuild targets file for rebuilding the database from scratch.  I don’t know if I’ve explained the rational for this.  The reason why you’d WANT to do this is so that each developer has a clean version of the database on their local machine.  This also includes the continuous integration environment.  Basically, you can do whatever you want to the database without fear, and in a minute or two, have a completely rebuilt database structure. DBDeploy (including the KTSC build task for dbdeploy) is used in this script to do change tracking on the database itself.  The MSBuild ExtensionPack is used in this target file.  You can get an MSBuild DBDeploy task here. There are two database scripts that you’ll see below.  First is the task for creating an admin (dbo) user in the system.  This script looks like the following: USE [master] GO If not Exists (select Name from sys.sql_logins where name = '$(User)') BEGIN CREATE LOGIN [$(User)] WITH PASSWORD=N'$(Password)', DEFAULT_DATABASE=[$(DatabaseName)], CHECK_EXPIRATION=OFF, CHECK_POLICY=OFF END GO EXEC master..sp_addsrvrolemember @loginame = N'$(User)', @rolename = N'sysadmin' GO USE [$(DatabaseName)] GO CREATE USER [$(User)] FOR LOGIN [$(User)] GO ALTER USER [$(User)] WITH DEFAULT_SCHEMA=[dbo] GO EXEC sp_addrolemember N'db_owner', N'$(User)' GO The second creates the changelog table.  This script can also be found in the dbdeploy.net install\scripts directory. CREATE TABLE changelog ( change_number INTEGER NOT NULL, delta_set VARCHAR(10) NOT NULL, start_dt DATETIME NOT NULL, complete_dt DATETIME NULL, applied_by VARCHAR(100) NOT NULL, description VARCHAR(500) NOT NULL ) GO ALTER TABLE changelog ADD CONSTRAINT Pkchangelog PRIMARY KEY (change_number, delta_set) GO Finally, Here’s the targets file. <Projectxmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0" DefaultTargets="Update">   <PropertyGroup>     <DatabaseName>TestDatabase</DatabaseName>     <Server>localhost</Server>     <ScriptDirectory>.\Scripts</ScriptDirectory>     <RebuildDirectory>.\Rebuild</RebuildDirectory>     <TestDataDirectory>.\TestData</TestDataDirectory>     <DbDeploy>.\DBDeploy</DbDeploy>     <User>TestUser</User>     <Password>TestPassword</Password>     <BCP>bcp</BCP>     <BCPOptions>-S$(Server) -U$(User) -P$(Password) -N -E -k</BCPOptions>     <OutputFileName>dbDeploy-output.sql</OutputFileName>     <UndoFileName>dbDeploy-output-undo.sql</UndoFileName>     <LastChangeToApply>99999</LastChangeToApply>   </PropertyGroup>     <ImportProject="$(MSBuildExtensionsPath)\ExtensionPack\4.0\MSBuild.ExtensionPack.tasks"/>   <UsingTask TaskName="Ktsc.Build.DBDeploy" AssemblyFile="$(DbDeploy)\Ktsc.Build.dll"/>   <ItemGroup>     <VariableInclude="DatabaseName">       <Value>$(DatabaseName)</Value>     </Variable>     <VariableInclude="Server">       <Value>$(Server)</Value>     </Variable>     <VariableInclude="User">       <Value>$(User)</Value>     </Variable>     <VariableInclude="Password">       <Value>$(Password)</Value>     </Variable>   </ItemGroup>     <TargetName="Rebuild">     <!--Take the database offline to disconnect any users. Requires that the current user is an admin of the sql server machine.-->     <MSBuild.ExtensionPack.SqlServer.SqlCmd Variables="@(Variable)" Database="$(DatabaseName)" TaskAction="Execute" CommandLineQuery ="ALTER DATABASE $(DatabaseName) SET OFFLINE WITH ROLLBACK IMMEDIATE"/>         <!--Bring it back online.  If you don't, the database files won't be deleted.-->     <MSBuild.ExtensionPack.Sql2008.DatabaseTaskAction="SetOnline" DatabaseItem="$(DatabaseName)"/>     <!--Delete the database, removing the existing files.-->     <MSBuild.ExtensionPack.Sql2008.DatabaseTaskAction="Delete" DatabaseItem="$(DatabaseName)"/>     <!--Create the new database in the default database path location.-->     <MSBuild.ExtensionPack.Sql2008.DatabaseTaskAction="Create" DatabaseItem="$(DatabaseName)" Force="True"/>         <!--Create admin user-->     <MSBuild.ExtensionPack.SqlServer.SqlCmd TaskAction="Execute" Server="(local)" Database="$(DatabaseName)" InputFiles="$(RebuildDirectory)\0002 Create Admin User.sql" Variables="@(Variable)" />     <!--Create the dbdeploy changelog.-->     <MSBuild.ExtensionPack.SqlServer.SqlCmd TaskAction="Execute" Server="(local)" Database="$(DatabaseName)" LogOn="$(User)" Password="$(Password)" InputFiles="$(RebuildDirectory)\0003 Create Changelog.sql" Variables="@(Variable)" />     <CallTarget Targets="Update;ImportData"/>     </Target>    <TargetName="Update" DependsOnTargets="CreateUpdateScript">     <MSBuild.ExtensionPack.SqlServer.SqlCmd TaskAction="Execute" Server="(local)" Database="$(DatabaseName)" LogOn="$(User)" Password="$(Password)" InputFiles="$(OutputFileName)" Variables="@(Variable)" />   </Target>   <TargetName="CreateUpdateScript">     <ktsc.Build.DBDeploy DbType="mssql"                                        DbConnection="User=$(User);Password=$(Password);Data Source=$(Server);Initial Catalog=$(DatabaseName);"                                        Dir="$(ScriptDirectory)"                                        OutputFile="..\$(OutputFileName)"                                        UndoOutputFile="..\$(UndoFileName)"                                        LastChangeToApply="$(LastChangeToApply)"/>   </Target>     <TargetName="ImportData">     <ItemGroup>       <TestData Include="$(TestDataDirectory)\*.dat"/>     </ItemGroup>     <ExecCommand="$(BCP) $(DatabaseName).dbo.%(TestData.Filename) in&quot;%(TestData.Identity)&quot;$(BCPOptions)"/>   </Target> </Project> Technorati Tags: MSBuild

  Read the article

• Programming Language, Turing Completeness and Turing Machine

  - by Amumu

  A programming language is said to be Turing Completeness if it can successfully simulate a universal TM. Let's take functional programming language for example. In functional programming, function has highest priority over anything. You can pass functions around like any primitives or objects. This is called first class function. In functional programming, your function does not produce side effect i.e. output strings onto screen, change the state of variables outside of its scope. Each function has a copy of its own objects if the objects are passed from the outside, and the copied objects are returned once the function finishes its job. Each function written purely in functional style is completely independent to anything outside of it. Thus, the complexity of the overall system is reduced. This is referred as referential transparency. In functional programming, each function can have its local variables kept its values even after the function exits. This is done by the garbage collector. The value can be reused the next time the function is called again. This is called memoization. A function usually should solve only one thing. It should model only one algorithm to answer a problem. Do you think that a function in a functional language with above properties simulate a Turing Machines? Functions (= algorithms = Turing Machines) are able to be passed around as input and returned as output. TM also accepts and simulate other TMs Memoization models the set of states of a Turing Machine. The memorized variables can be used to determine states of a TM (i.e. which lines to execute, what behavior should it take in a give state ...). Also, you can use memoization to simulate your internal tape storage. In language like C/C++, when a function exits, you lose all of its internal data (unless you store it elsewhere outside of its scope). The set of symbols are the set of all strings in a programming language, which is the higher level and human-readable version of machine code (opcode) Start state is the beginning of the function. However, with memoization, start state can be determined by memoization or if you want, switch/if-else statement in imperative programming language. But then, you can't Final accepting state when the function returns a value, or rejects if an exception happens. Thus, the function (= algorithm = TM) is decidable. Otherwise, it's undecidable. I'm not sure about this. What do you think? Is my thinking true on all of this? The reason I bring function in functional programming because I think it's closer to the idea of TM. What experience with other programming languages do you have which make you feel the idea of TM and the ideas of Computer Science in general? Can you specify how you think?

  Read the article

• JavaScript Class Patterns &ndash; In CoffeeScript

  - by Liam McLennan

  Recently I wrote about JavaScript class patterns, and in particular, my favourite class pattern that uses closure to provide encapsulation. A class to represent a person, with a name and an age, looks like this: var Person = (function() { // private variables go here var name,age; function constructor(n, a) { name = n; age = a; } constructor.prototype = { toString: function() { return name + " is " + age + " years old."; } }; return constructor; })(); var john = new Person("John Galt", 50); console.log(john.toString()); Today I have been experimenting with coding for node.js in CoffeeScript. One of the first things I wanted to do was to try and implement my class pattern in CoffeeScript and then see how it compared to CoffeeScript’s built-in class keyword. The above Person class, implemented in CoffeeScript, looks like this: # JavaScript style class using closure to provide private methods Person = (() -> [name,age] = [{},{}] constructor = (n, a) -> [name,age] = [n,a] null constructor.prototype = toString: () -> "name is #{name} age is #{age} years old" constructor )() I am satisfied with how this came out, but there are a few nasty bits. To declare the two private variables in javascript is as simple as var name,age; but in CoffeeScript I have to assign a value, hence [name,age] = [{},{}]. The other major issue occurred because of CoffeeScript’s implicit function returns. The last statement in any function is returned, so I had to add null to the end of the constructor to get it to work. The great thing about the technique just presented is that it provides encapsulation ie the name and age variables are not visible outside of the Person class. CoffeeScript classes do not provide encapsulation, but they do provide nicer syntax. The Person class using native CoffeeScript classes is: # CoffeeScript style class using the class keyword class CoffeePerson constructor: (@name, @age) -> toString: () -> "name is #{@name} age is #{@age} years old" felix = new CoffeePerson "Felix Hoenikker", 63 console.log felix.toString() So now I have a trade-off: nice syntax against encapsulation. I think I will experiment with both strategies in my project and see which works out better.

  Read the article

• JS closures - Passing a function to a child, how should the shared object be accessed

  - by slicedtoad

  I have a design and am wondering what the appropriate way to access variables is. I'll demonstrate with this example since I can't seem to describe it better than the title. Term is an object representing a bunch of time data (a repeating duration of time defined by a bunch of attributes) Term has some print functionality but does not implement the print functions itself, rather they are passed in as anonymous functions by the parent. This would be similar to how shaders can be passed to a renderer rather than defined by the renderer. A container (let's call it Box) has a Schedule object that can understand and use Term objects. Box creates Term objects and passes them to Schedule as required. Box also defines the print functions stored in Term. A print function usually takes an argument and uses it to return a string based on that argument and Term's internal data. Sometime the print function could also use data stored in Schedule, though. I'm calling this data shared. So, the question is, what is the best way to access this shared data. I have a lot of options since JS has closures and I'm not familiar enough to know if I should be using them or avoiding them in this case. Options: Create a local "reference" (term used lightly) to the shared data (data is not a primitive) when defining the print function by accessing the shared data through Schedule from Box. Example: var schedule = function(){ var sched = Schedule(); var t1 = Term( function(x){ // Term.print() return (x + sched.data).format(); }); }; Bind it to Term explicitly. (Pass it in Term's constructor or something). Or bind it in Sched after Box passes it. And then access it as an attribute of Term. Pass it in at the same time x is passed to the print function, (from sched). This is the most familiar way for my but it doesn't feel right given JS's closure ability. Do something weird like bind some context and arguments to print. I'm hoping the correct answer isn't purely subjective. If it is, then I guess the answer is just "do whatever works". But I feel like there are some significant differences between the approaches that could have a large impact when stretched beyond my small example.

  Read the article

• OOP private method parameters coding style

  - by Jake

  After coding for many years as a solo programmer, I have come to feel that most of the time there are many benefits to write private member functions with all of the used member variables included in the parameter list, especially development stage. This allow me to check at one look what member variables are used and also allow me to supply other values for tests and debugging. Also, a change in code by removing a particular member variable can break many functions. In this case however, the private function remains isolated am I can still call it using other values without fixing the function. Is this a bad idea afterall, especially in a team environment? Is it like redundant or confusing, or are there better ways?

  Read the article

• Algorithmic Forecasting and Pattern Recognition

  - by Ryan King

  Say a user could enter project data into my software. Each project has 2 variables "size" and "work" and they're related but the relationship is not known. Is there a way to programmatically determine the relationship between the variables based on previous data and forecast the amount of work provided if only given the size of the project in the future? For Example, say the user had manually entered the following projects. Project 1 - Size:1, Work: 4 Project 2 - Size:2, Work: 7 Project 3 - Size:3, Work: 10 Project 4 - Size:4, Work: x What should I look into to be able to programmatically determine, that Work = Size*3+1 and therefor be able to say that x=13?

  Read the article

• Architecture for a template-building, WYSIWIG application

  - by Sam Selikoff

  I'm building a WYSIWYG designer in Ember.js. The designer will allow users to create campaigns - think MailChimp. To build a campaign, users will choose an existing template. The template will have a defined layout. The user will then be taken to the designer, where he will be able to edit the text and style, and additionally change some layout options. I've been thinking about how best to go about structuring this app, and there are a few hurdles. Specifically, the output of the campaign will be dynamic: eventually, it will be published somewhere, and when the consumers (not my users, but the people clicking on the campaign that my user created) visit the campaign, certain pieces of data will change, depending on the type of consumer viewing the campaign. That means the ultimate output of the designer will be a dynamic site. The data that is dynamic for this site - the end product - will not be manipulated by the user in the designer. However, the data that will be manipulated by the user in the designer are things like copy, styles, layout options, etc. I'll call the first set of variables server-side data, and the second client-side data. It seems, then, that the process will go something like this: I'll need to create templates for this designer that have two dynamic segments. For instance, the server-side data could be Liquid expressions, and the client-side data Handlebars expressions. When the user creates a campaign, I would compile the template on the back end using some dummy data for the server-side variables, and serve up a handlebars template to the Ember app. The user would then edit the template, and the Ember app would save all his edits to the JS variables that were powering the template. This way he'd be able to preview the template. When he saves, he'll send back the selected template, along with all the data and options he's made. When it comes time to publish, the back-end system will have to do two things: compile the template with Handlebars using the campaign data, and then compile the template with Liquid using the server-side data Is my thinking roughly accurate about this, or is there a simpler way?

  Read the article

< Previous Page | 130 131 132 133 134 135 136 137 138 139 140 141  | Next Page >