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  • What is the best approach using JDBC for parameterizing an IN clause?

    - by Uri
    Say that I have a query of the form SELECT * FROM MYTABLE WHERE MYCOL in (?) And I want to parameterize the arguments to in. Is there a straightforward way to do this in Java with JDBC, in a way that could work on multiple databases without modifying the SQL itself? The closest question I've found had to do with C#, I'm wondering if there is something different for Java/JDBC.

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  • Best approach to creating a database driven Java website?

    - by Craig Whitley
    I'm fairly new to programming and new to java, but I'd like to jump in the deep end with a little database driven website project. I've read quite a lot about requirements in the 'real world' requesting experience with Spring and Hibernate, so I have those installed on netbeans and a project created (if I hit run I get the default spring page). Now I just need a little guidance as to where to start designing my app (please tell me if I'm getting in a bit too over my head for a beginner!). Should I start off with my classes? - create all my classes as they map to my database tables and decide which attributes and methods each will require? Can anyone suggest any good books for maybe.. making a java based website from scratch (i.e. from design right through to deployment) that might be useful for a beginner? Any help appreciated thanks.

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  • Why C++ people loves multithreading when it comes to performances?

    - by user1849534
    I have a question, it's about why programmers seems to love concurrency and multi-threaded programs in general. I'm considering 2 main approach here: an async approach basically based on signals, or just an async approach as called by many papers and languages like the new C# 5.0 for example, and a "companion thread" that maanges the policy of your pipeline a concurrent approach or multi-threading approach I will just say that I'm thinking about the hardware here and the worst case scenario, and I have tested this 2 paradigms myself, the async paradigm is a winner at the point that I don't get why people 90% of the time talk about concurrency when they wont to speed up things or make a good use of their resources. I have tested multi-threaded programs and async program on an old machine with an Intel quad-core that doesn't offer a memory controller inside the CPU, the memory is managed entirely by the motherboard, well in this case performances are horrible with a multi-threaded application, even a relatively low number of threads like 3-4-5 can be a problem, the application is unresponsive and is just slow and unpleasant. A good async approach is, on the other hand, probably not faster but it's not worst either, my application just waits for the result and doesn't hangs, it's responsive and there is a much better scaling going on. I have also discovered that a context change in the threading world it's not that cheap in real world scenario, it's infact quite expensive especially when you have more than 2 threads that need to cycle and swap among each other to be computed. On modern CPUs the situation it's not really that different, the memory controller it's integrated but my point is that an x86 CPUs is basically a serial machine and the memory controller works the same way as with the old machine with an external memory controller on the motherboard. The context switch is still a relevant cost in my application and the fact that the memory controller it's integrated or that the newer CPU have more than 2 core it's not bargain for me. For what i have experienced the concurrent approach is good in theory but not that good in practice, with the memory model imposed by the hardware, it's hard to make a good use of this paradigm, also it introduces a lot of issues ranging from the use of my data structures to the join of multiple threads. Also both paradigms do not offer any security abut when the task or the job will be done in a certain point in time, making them really similar from a functional point of view. According to the X86 memory model, why the majority of people suggest to use concurrency with C++ and not just an async aproach ? Also why not considering the worst case scenario of a computer where the context switch is probably more expensive than the computation itself ?

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  • What's my best approach on this simple hierarchy Java Problem?

    - by Nazgulled
    First, I'm sorry for the question title but I can't think of a better one to describe my problem. Feel free to change it :) Let's say I have this abstract class Box which implements a couple of constructors, methods and whatever on some private variables. Then I have a couple of sub classes like BoxA and BoxB. Both of these implement extra things. Now I have another abstract class Shape and a few sub classes like Square and Circle. For both BoxA and BoxB I need to have a list of Shape objects but I need to make sure that only Square objects go into BoxA's list and only Circle objects go into BoxB's list. For that list (on each box), I need to have a get() and set() method and also a addShape() and removeShape() methods. Another important thing to know is that for each box created, either BoxA or BoxB, each respectively Shape list is exactly the same. Let's say I create a list of Square's named ls and two BoxA objects named boxA1 and boxA2. No matter what, both boxA1 and boxA2 must have the same ls list. This is my idea: public abstract class Box { // private instance variables public Box() { // constructor stuff } // public instance methods } public class BoxA extends Box { // private instance variables private static List<Shape> list; public BoxA() { // constructor stuff } // public instance methods public static List<Square> getList() { List<Square> aux = new ArrayList<Square>(); for(Square s : list.values()) { aux.add(s.clone()); // I know what I'm doing with this clone, don't worry about it } return aux; } public static void setList(List<Square> newList) { list = new ArrayList<Square>(newList); } public static void addShape(Square s) { list.add(s); } public static void removeShape(Square s) { list.remove(list.indexOf(s)); } } As the list needs to be the same for that type of object, I declared as static and all methods that work with that list are also static. Now, for BoxB the class would be almost the same regarding the list stuff. I would only replace Square by Triangle and the problem was solved. So, for each BoxA object created, the list would be only one and the same for each BoxB object created, but a different type of list of course. So, what's my problem you ask? Well, I don't like the code... The getList(), setList(), addShape() and removeShape() methods are basically repeated for BoxA and BoxB, only the type of the objects that the list will hold is different. I can't think of way to do it in the super class Box instead. Doing it statically too, using Shape instead of Square and Triangle, wouldn't work because the list would be only one and I need it to be only one but for each sub class of Box. How could I do this differently and better? P.S: I could not describe my real example because I don't know the correct words in English for the stuff I'm doing, so I just used a box and shapes example, but it's basically the same.

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  • Need a design approach or suggestion for a simple structure using Servlet.

    - by akshay
    Hi I have to design such that whenever user pass a query I process it using servlet and then call the js page to draw the chart 1 user writes a query on a page 2 the page call the servelt class public class MyServlet extends Httpservlet implements DataSourceServlet {..... return data The user see a beautiful string like this.. google.visualization.Query.setResponse......... /Tiger'},{v:80.0}, {v:false}]}]}}); 3 when the user hits on different html page myhtml.js it draws the chart. I want the Myservlet class itself call the myhtml.js page and draw the chart directly. and want to eliminate the beautiful string google.visualization.Query.setResponse......... /Tiger'},{v:80.0}, {v:false}]}]}}); from coming on user's browser What should i do? I tried using functions to call another page like request dispatcher(), redirect() calling myhtml.js page directly after myservlet process the query results. But i get the result like this google.visualization.Query.setResponse......... /Tiger'},{v:80.0}, {v:false}]}]}}); and the entire myhtml.js code page below it on the browsers that to without the chart been draw. Is there anyway to element the beautiful string from coming on clients browser and only show them the chart been drawn ? :) This is the small tutorial i am following http://code.google.com/apis/visualization/documentation/dev/dsl_get_started.html

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  • Best approach to update a control after an Ajax request?

    - by Cuga
    I have a webpage that fires off an Ajax request which stores some data to a database and I want to update the webpage so that the user can see their changes have been submitted. There are at least 3 ways I can think of accomplishing this: Immediately update the webpage with plain JavaScript by grabbing the contents of the user's inputted text and immediately inserting it where it belongs. Have the ajax call return the stored text as the response, grab the response, and then insert this text where it belongs on the page using JavaScript Have the ajax call return a flag (say, true for successful db write, false otherwise), and if the flag is true, use JavaScript to grab the user's contents from the input control and insert it where it belongs elsewhere on the page Or another method not mentioned...? I don't mean this to be subjective, I just don't know which would be the best method to apply. My instinct tells me to go with the third item (return a flag, then update the field). Is this the best way? Thanks

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  • What's the best approach to printing/reporting from WPF?

    - by Matt Hamilton
    I have an upcoming project which will have to be able to print simple reports from its data. It'll be WPF-based, and I'm wondering which way to go. I know that WPF introduces its own printing technology (based on XPS) which looks quite easy to use. However, part of me wonders whether it would just be easier to use the ReportViewer control and embed it in a Windows Forms host control, since that will give users the ability to export to a variety of formats as well as print. Has anyone had any experience with printing/reporting from WPF? Which direction would you recommend?

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  • Using SVN alone or in small workgroups - workflow approach?

    - by Industrial
    Hi everybody, I have spent some months working on a web application and we're come close to production stage. It's soon time to expand the development group with 1-3 people on this project. I have not too much experience on working with SVN, but It's obviously the choice for a big part of the larger companies out there, so I am guessing that the pros of SVN without a doubt outweights the time spent on commit/check ins / check outs etc. The workflow seems to become a bit more complicated with SVN, and even though I have read Version Control with Subversion by O'Reilly Media and I am not sure yet if it's overkill to use SVN for any reasons besides backup when developing alone or in a small (1-3 people) workgroup? How do you do it? What's your workflow with version control while working alone or in small workgroups? Thanks!

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  • Which approach to create the data access layer has the highest performance?

    - by pooyakhamooshi
    I have to create a very high performance application. Currently, I am using Entity Framework for my data access layer. My application has to insert some communication data almost every second. I found that Entity Framework is slow; it has about 2 seconds delay to finish the SaveChanges() method. I was thinking I have the following options: 1. Create the data access layer myself using ADO.NET; using stored procedures or ad-hoc queries 2. Use Enterprise Library Data access Layer 3. Use NHibernate 4. Use Repository Factory: http://pooyakhamooshi.blogspot.com/search?q=repository What do you think? which one is quicker for inserting data? Which one is quicker to set up?

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  • Looking for an approach to program a mobile website for any device. Are there any?

    - by ChrisBenyamin
    My wish is to know how I can program a mobile website, that fit to all mobile phones. Are there any special approaches to recognize a device and render the code according to it? Which tools and coding languages are required? My first thought was to hold the website in XML, which would be parsed depending on the device. You have to consider old phones, even devices with only wap support. For example: The mobile website has to recognize Nokia N75 and render/send the code that looks optimal for this device. Same thing with an iPhone or a Motorola Razr.

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  • what is the best approach for to use openGL in the web?

    - by Y_Y
    I wrote a program in C++/OpenGL (using Dev-C++ compiler) for my calculus 2 class. The teacher liked the program and he requested me to somehow put it online so that instead of downloading the .exe file and run it the web browser will run it automatically just like a java applet. The question is: How if possible, can I display a C++/OpenGL program in a web browser? I am thinking of moving to JOGL which is a java interpretation of OpenGL but I rather stay in C++ since I am more familiar with it. Also is there any other better and easier 3D web base API that I can consider?

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  • JUnit confusion: use 'extend Testcase' or '@Test' ?

    - by Rabarberski
    I've found the proper use (or at least the documentation) of JUnit very confusing. This question serves both as a future reference and as a real question. If I've understood correctly, there are two main approaches to create and run a JUnit test: Approach A: create a class that extends TestCase, and start test methods with the word test. When running the class as a JUnit Test (in Eclipse), all methods starting with the word test are automatically run. import junit.framework.TestCase; public class DummyTestA extends TestCase { public void testSum() { int a = 5; int b = 10; int result = a + b; assertEquals(15, result); } } Approach B: create a 'normal' class and prepend a @Test annotation to the method. Note that you do NOT have to start the method with the word test. import org.junit.*; import static org.junit.Assert.*; public class DummyTestB { @Test public void Sum() { int a = 5; int b = 10; int result = a + b; assertEquals(15, result); } } Mixing the two seems not to be a good idea, see e.g. this stackoverflow question: Now, my questions(s): What is the preferred approach, or when would you use one instead of the other? Approach B allows for testing for exceptions by extending the @Test annotation like in @Test(expected = ArithmeticException.class). But how do you test for exceptions when using approach A? When using approach A, you can group a number of test classes in a test suite. TestSuite suite = new TestSuite("All tests");<br/> suite.addTestSuite(DummyTestA.class); suite.addTestSuite(DummyTestAbis.class);` But this can't be used with approach B (since each testclass should subclass TestCase). What is the proper way to group tests for approach B?

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  • Twitter's new approach of third party application? How would you see this move as developer.... especially you plan to build a twitter client.

    - by MobileDev123
    Just today morning I have read news that twitter has issued a warning to developers not to make any new third party client, the official announcement can be read here. As a programmer, how do you see this move of twitter? Does it seems that they want to standardize the behavior of third party client or they don't want any new client in favor of the default clients they have made? What if anybody wants to create a new client? Is there any guidelines that-if followed- ensure that we can create a new mobile client? Or we should stop thinking about it? What are the option for the developers who want to build some clients for twitter? I can realize that I have asked too many questions, but I still think that there can be one common answer.

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  • What is best way to remove ProgressDialog

    - by Sunil Kumar Sahoo
    I have created a progress dialog by ProgressDialog progressDialog = null; // create instance variable of ProgressDialog int dialogID = 1; //to create progress dialog protected Dialog onCreateDialog(int id) { progressDialog = new ProgressDialog(context); progressDialog.setMessage(message); progressDialog.setIcon(android.R.id.icon); return progressDialog; } // to show progressdialog showDialog(dialogID); To remove the dialog I am able to use any of the following three approaches approach-1 if(progressDialog != null){ progressDialog.dismiss(); } approach-2 if(progressDialog != null){ progressDialog.cancel(); } approach-3 removeDialog(dialogID); I found second approach is more effective than first approach. and if I have to use with more than one progressdialog it is easier to use approach-3. But what is the best way to destroy a progressdialog and How?

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  • Designing a social network with CQRS, graph databases and relational databases in mind

    - by Siraj Mansour
    I have done quite an amount of research on the topic so far, but i couldn't come up with a conclusion to make up my mind. I am designing a social network and during my research i stumbled upon graph databases, i found neo4j pretty interesting for user relations and traversing through nodes. I also thought of using a relational database such as MS-SQL or MySQL to store entity data only and depending on neo4j for connections between entities. Of course this means more work in my application to store and pull data in and out of 2 different sources. My first question : Is using this approach (graph + relational) a good approach for designing my social network keeping in mind that users on social networks don't have to in synch with real data by split second ? What are the positives and negatives of this approach ? My Second question : I've been doing some reading on CQRS and as i understood it is mostly useful for collaborative environments, and environments where users see a lot of "stale" data. social networks has shared comments, events, etc .. and many users query or update the same data. Could CQRS be a helpful approach ? Would it give any performance/scalability benefits or non-useful complexity ? Is it fairly applicable with my possible choice of (graph + relational) databases approach mentioned in the question above ? My purpose is to know if the approaches i have mentioned above seem good enough for the business context.

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  • Storing large data in HTTP Session (Java Application)

    - by Umesh Awasthi
    I am asking this question in continuation with http-session-or-database-approach. I am planning to follow this approach. When user add product to cart, create a Cart Model, add items to cart and save to DB. Convert Cart model to cart data and save it to HTTP session. Any update/ edit update underlying cart in DB and update data snap shot in Session. When user click on view cart page, just pick cart data from Session and display to customer. I have following queries regarding HTTP Session How good is it to store large data (Shopping Cart) in Session? How scalable this approach can be ? (With respect to Session) Won't my application going to eat and demand a lot of memory? Is my approach is fine or do i need to consider other points while designing this? Though, we can control what all cart data should be stored in the Session, but still we need to have certain information in cart data being stored in session?

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  • Suitability of ground fog using layered alpha quads?

    - by Nick Wiggill
    A layered approach would use a series of massive alpha-textured quads arranged parallel to the ground, intersecting all intervening terrain geometry, to provide the illusion of ground fog quite effectively from high up, looking down, and somewhat less effectively when inside the fog and looking toward the horizon (see image below). Alternatively, a shader-heavy approach would instead calculate density as function of view distance into the ground fog substrate, and output the fragment value based on that. Without having to performance-test each approach myself, I would like first to hear others' experiences (not speculation!) on what sort of performance impact the layered alpha texture approach is likely to have. I ask specifically due to the oft-cited impacts of overdraw (not sure how fill-rate bound your average desktop system is). A list of games using this approach, particularly older games, would be immensely useful: if this was viable on pre DX9/OpenGL2 hardware, it is likely to work fine for me. One big question is in regards to this sort of effect: (Image credit goes to Lume of lume.com) Notice how the vertical fog gradation is continuous / smooth. OTOH, using textured quad layers, I can only assume that layers would be mighty obvious when walking through them -- the more sparse they were, the more obvious this would be. This is in contrast to where fog planes are aligned to face the player every frame, where this coarseness would be much less obvious.

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  • Clean way to use mutable implementation of Immutable interfaces for encapsulation

    - by dsollen
    My code is working on some compost relationship which creates a tree structure, class A has many children of type B, which has many children of type C etc. The lowest level class, call it bar, also points to a connected bar class. This effectively makes nearly every object in my domain inter-connected. Immutable objects would be problematic due to the expense of rebuilding almost all of my domain to make a single change to one class. I chose to go with an interface approach. Every object has an Immutable interface which only publishes the getter methods. I have controller objects which constructs the domain objects and thus has reference to the full objects, thus capable of calling the setter methods; but only ever publishes the immutable interface. Any change requested will go through the controller. So something like this: public interface ImmutableFoo{ public Bar getBar(); public Location getLocation(); } public class Foo implements ImmutableFoo{ private Bar bar; private Location location; @Override public Bar getBar(){ return Bar; } public void setBar(Bar bar){ this.bar=bar; } @Override public Location getLocation(){ return Location; } } public class Controller{ Private Map<Location, Foo> fooMap; public ImmutableFoo addBar(Bar bar){ Foo foo=fooMap.get(bar.getLocation()); if(foo!=null) foo.addBar(bar); return foo; } } I felt the basic approach seems sensible, however, when I speak to others they always seem to have trouble envisioning what I'm describing, which leaves me concerned that I may have a larger design issue then I'm aware of. Is it problematic to have domain objects so tightly coupled, or to use the quasi-mutable approach to modifying them? Assuming that the design approach itself isn't inherently flawed the particular discussion which left me wondering about my approach had to do with the presence of business logic in the domain objects. Currently I have my setter methods in the mutable objects do error checking and all other logic required to verify and make a change to the object. It was suggested that this should be pulled out into a service class, which applies all the business logic, to simplify my domain objects. I understand the advantage in mocking/testing and general separation of logic into two classes. However, with a service method/object It seems I loose some of the advantage of polymorphism, I can't override a base class to add in new error checking or business logic. It seems, if my polymorphic classes were complicated enough, I would end up with a service method that has to check a dozen flags to decide what error checking and business logic applies. So, for example, if I wanted to have a childFoo which also had a size field which should be compared to bar before adding par my current approach would look something like this. public class Foo implements ImmutableFoo{ public void addBar(Bar bar){ if(!getLocation().equals(bar.getLocation()) throw new LocationException(); this.bar=bar; } } public interface ImmutableChildFoo extends ImmutableFoo{ public int getSize(); } public ChildFoo extends Foo implements ImmutableChildFoo{ private int size; @Override public int getSize(){ return size; } @Override public void addBar(Bar bar){ if(getSize()<bar.getSize()){ throw new LocationException(); super.addBar(bar); } My colleague was suggesting instead having a service object that looks something like this (over simplified, the 'service' object would likely be more complex). public interface ImmutableFoo{ ///original interface, presumably used in other methods public Location getLocation(); public boolean isChildFoo(); } public interface ImmutableSizedFoo implements ImmutableFoo{ public int getSize(); } public class Foo implements ImmutableSizedFoo{ public Bar bar; @Override public void addBar(Bar bar){ this.bar=bar; } @Override public int getSize(){ //default size if no size is known return 0; } @Override public boolean isChildFoo return false; } } public ChildFoo extends Foo{ private int size; @Override public int getSize(){ return size; } @Override public boolean isChildFoo(); return true; } } public class Controller{ Private Map<Location, Foo> fooMap; public ImmutableSizedFoo addBar(Bar bar){ Foo foo=fooMap.get(bar.getLocation()); service.addBarToFoo(foo, bar); returned foo; } public class Service{ public static void addBarToFoo(Foo foo, Bar bar){ if(foo==null) return; if(!foo.getLocation().equals(bar.getLocation())) throw new LocationException(); if(foo.isChildFoo() && foo.getSize()<bar.getSize()) throw new LocationException(); foo.setBar(bar); } } } Is the recommended approach of using services and inversion of control inherently superior, or superior in certain cases, to overriding methods directly? If so is there a good way to go with the service approach while not loosing the power of polymorphism to override some of the behavior?

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  • Androids development life cycle model query [closed]

    - by Andrew Rose
    I have been currently researching Google and their approach to marketing the Android OS. Primarily using an open source technique with the Open Hand Alliance and out souring through third-party developers. I'm now keen to investigate their approach using various development life cycle models in the form of waterfall, spiral, scrum, agile etc. And i'm just curious to have some feedback from professionals and what approach they think Google would use to have a positive effect on their business. Thanks for your time Andy Rose

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  • 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.

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  • 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.

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  • What is a good strategy for binding view objects to model objects in C++?

    - by B.J.
    Imagine I have a rich data model that is represented by a hierarchy of objects. I also have a view hierarchy with views that can extract required data from model objects and display the data (and allow the user to manipulate the data). Actually, there could be multiple view hierarchies that can represent and manipulate the model (e.g. an overview-detail view and a direct manipulation view). My current approach for this is for the controller layer to store a reference to the underlying model object in the View object. The view object can then get the current data from the model for display, and can send the model object messages to update the data. View objects are effectively observers of the model objects and the model objects broadcast notifications when properties change. This approach allows all the views to update simultaneously when any view changes the model. Implemented carefully, this all works. However, it does require a lot of work to ensure that no view or model objects hold any stale references to model objects. The user can delete model objects or sub-hierarchies of the model at any time. Ensuring that all the view objects that hold references to the model objects that have been deleted is time-consuming and difficult. It feels like the approach I have been taking is not especially clean; while I don't want to have to have explicit code in the controller layer for mediating the communication between the views and the model, it seems like there must be a better (implicit) approach for establishing bindings between the view and the model and between related model objects. In particular, I am looking for an approach (in C++) that understands two key points: There is a many to one relationship between view and model objects If the underlying model object is destroyed, all the dependent view objects must be cleaned up so that no stale references exist While shared_ptr and weak_ptr can be used to manage the lifetimes of the underlying model objects and allows for weak references from the view to the model, they don't provide for notification of the destruction of the underlying object (they do in the sense that the use of a stale weak_ptr allows for notification), but I need an approach that notifies the dependent objects that their weak reference is going away. Can anyone suggest a good strategy to manage this?

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