Search Results

Search found 22961 results on 919 pages for 'memory management'.

Page 816/919 | < Previous Page | 812 813 814 815 816 817 818 819 820 821 822 823  | Next Page >

  • Accessing Members of Containing Objects from Contained Objects.

    - by Bunkai.Satori
    If I have several levels of object containment (one object defines and instantiates another object which define and instantiate another object..), is it possible to get access to upper, containing - object variables and functions, please? Example: class CObjectOne { public: CObjectOne::CObjectOne() { Create(); }; void Create(); std::vector<ObjectTwo>vObejctsTwo; int nVariableOne; } bool CObjectOne::Create() { CObjectTwo ObjectTwo(this); vObjectsTwo.push_back(ObjectTwo); } class CObjectTwo { public: CObjectTwo::CObjectTwo(CObjectOne* pObject) { pObjectOne = pObject; Create(); }; void Create(); CObjectOne* GetObjectOne(){return pObjectOne;}; std::vector<CObjectTrhee>vObjectsTrhee; CObjectOne* pObjectOne; int nVariableTwo; } bool CObjectTwo::Create() { CObjectThree ObjectThree(this); vObjectsThree.push_back(ObjectThree); } class CObjectThree { public: CObjectThree::CObjectThree(CObjectTwo* pObject) { pObjectTwo = pObject; Create(); }; void Create(); CObjectTwo* GetObjectTwo(){return pObjectTwo;}; std::vector<CObjectsFour>vObjectsFour; CObjectTwo* pObjectTwo; int nVariableThree; } bool CObjectThree::Create() { CObjectFour ObjectFour(this); vObjectsFour.push_back(ObjectFour); } main() { CObjectOne myObject1; } Say, that from within CObjectThree I need to access nVariableOne in CObjectOne. I would like to do it as follows: int nValue = vObjectThree[index].GetObjectTwo()->GetObjectOne()->nVariable1; However, after compiling and running my application, I get Memory Access Violation error. What is wrong with the code above(it is example, and might contain spelling mistakes)? Do I have to create the objects dynamically instead of statically? Is there any other way how to achieve variables stored in containing objects from withing contained objects?

    Read the article

  • PHP in Wordpress Posts - Is this okay?

    - by Thomas
    I've been working with some long lists of information and I've come up with a good way to post it in various formats on my wordpress blog posts. I installed the exec-PHP plugin, which allows you to run php in posts. I then created a new table (NEWTABLE) in my wordpress database and filled that table with names, scores, and other stuff. I was then able to use some pretty simple code to display the information in a wordpress post. Below is an example, but you could really do whatever you wanted. My question is - is there a problem with doing this? with security? or memory? I could just type out all the information in each post, but this is really much nicer. Any thoughts are appreciated. <?php $theResult = mysql_query("SELECT * FROM NEWTABLE WHERE Score < 100 ORDER BY LastName"); while($row = mysql_fetch_array($theResult)) { echo $row['FirstName']; echo " " . $row['LastName']; echo " " . $row['Score']; echo "<br />"; } ?>

    Read the article

  • Is there a difference between starting an application from the OS or from adb

    - by aruwen
    I do have a curious error in my application. My app crashes (don't mind the crash, I roughly know why - classloader) when I start the application from the OS directly, then kill it from the background via any Task Killer (this is one of the few ways to reproduce the crash consistently - simulating the OS freeing memory and closing the application) and try to restart it again. The thing is, if I start the application via adb shell using the following command: adb shell am start -a android.intent.action.MAIN -n com.my.packagename/myLaunchActivity I cannot reproduce the crash. So is there any difference in how Android OS calls the application as opposed to the above call? EDIT: added the manifest (just changed names) <?xml version="1.0" ?> <manifest android:versionCode="5" android:versionName="1.05" package="com.my.sample" xmlns:android="http://schemas.android.com/apk/res/android"> <uses-sdk android:minSdkVersion="7"/> <application android:icon="@drawable/square_my_logo" android:label="@string/app_name"> <activity android:label="@string/app_name" android:name="com.my.InfoActivity" android:screenOrientation="landscape"></activity> <activity android:label="@string/app_name" android:name="com.my2.KickStart" android:screenOrientation="landscape"/> <activity android:label="@string/app_name" android:name="com.my2.Launcher" android:screenOrientation="landscape"> <intent-filter> <action android:name="android.intent.action.MAIN"/> <category android:name="android.intent.category.LAUNCHER"/> </intent-filter> </activity> </application> <uses-permission android:name="android.permission.INTERNET"/> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/></manifest> starting the com.my2.Launcher from the adb shell

    Read the article

  • Technical choices in unmarshaling hash-consed data

    - by Pascal Cuoq
    There seems to be quite a bit of folklore knowledge floating about in restricted circles about the pitfalls of hash-consing combined with marshaling-unmarshaling of data. I am looking for citable references to these tidbits. For instance, someone once pointed me to library aterm and mentioned that the authors had clearly thought about this and that the representation on disk was bottom-up (children of a node come before the node itself in the data stream). This is indeed the right way to do things when you need to re-share each node (with a possible identical node already in memory). This re-sharing pass needs to be done bottom-up, so the unmarshaling itself might as well be, too, so that it's possible to do everything in a single pass. I am in the process of describing difficulties encountered in our own context, and the solutions we found. I would appreciate any citable reference to the kind of aforementioned folklore knowledge. Some people obviously have encountered the problems before (the aterm library is only one example). But I didn't find anything in writing. Even the little piece of information I have about aterm is hear-say. I am not worried it's not reliable (you can't make this up), but "personal communication" and "look how it's done in the source code" are considered poor form in citations. I have enough references on hash-consing alone. I am only interested in references where it interferes with other aspects of programming, such as marshaling or distribution.

    Read the article

  • Minimal assembler program for CP/M 3.1 (z80)

    - by Andrew J. Brehm
    I seem to be losing the battle against my stupidity. This site explains the system calls under various versions of CP/M. However, when I try to use call 2 (C_WRITE, console output), nothing much happens. I have the following code. ORG 100h LD E,'a' LD C,2 CALL 5 CALL 0 I recite this here from memory. If there are typos, rest assured they were not in the original since the file did compile and I had a COM file to start. I am thinking the lines mean the following: Make sure this gets loaded at address 100h (0h to FFh being the zero page). Load ASCII 'a' into E register for system call 2. Load integer 2 into C register for system call 2. Make system call (JMP to system call is at address 5 in zero page). End program (Exit command is at address 0 in zero page). The program starts and exits with no problems. If I remove the last command, it hangs the computer (which I guess is also expected and shows that CALL 0 works). However, it does not print the ASCII character. (But it does print an extra new line, but the system might have done that.) How can I get my CP/M program to do what the system call is supposed to do? What am I doing wrong?

    Read the article

  • Special technology needed for browser based chat?

    - by orokusaki
    On this post, I read about the usage of XMPP. Is this sort of thing necessary, and more importantly, my main question expanded: Can a chat server and client be built efficiently using only standard HTTP and browser technologies (such as PHP and JS, or RoR and JS, etc)? Or, is it best to stick with old protocols like XMPP find a way to integrate them with my application? I looked into CampFire via LiveHTTPHeaders and Firebug for about 5 minutes, and it appears to use Ajax to send a request which is never answered until another chat happens. Is this just CampFire opening a new thread on the server to listen for an update and then returning a response to the request when the thread hears an update? I noticed that they're requesting on a specific port (8043 if memory serves me) which makes me think that they're doing something more complex than just what I mentioned. Also, the URL requested started with /tcp/ which I found interesting. Note: I don't expect to ever have more than 150 users live-chatting in all the rooms combined at the same time. I understand that if I was building a hosted pay for chat service like CampFire with thousands of concurrent users, it would behoove me to invest time in researching special technologies vs trying to reinvent the wheel in a simple way in my app. Also, if you're going to do it with server polling, how often would you personally poll to maximize response without slamming the server?

    Read the article

  • Are there pitfalls to using static class/event as an application message bus

    - by Doug Clutter
    I have a static generic class that helps me move events around with very little overhead: public static class MessageBus<T> where T : EventArgs { public static event EventHandler<T> MessageReceived; public static void SendMessage(object sender, T message) { if (MessageReceived != null) MessageReceived(sender, message); } } To create a system-wide message bus, I simply need to define an EventArgs class to pass around any arbitrary bits of information: class MyEventArgs : EventArgs { public string Message { get; set; } } Anywhere I'm interested in this event, I just wire up a handler: MessageBus<MyEventArgs>.MessageReceived += (s,e) => DoSomething(); Likewise, triggering the event is just as easy: MessageBus<MyEventArgs>.SendMessage(this, new MyEventArgs() {Message="hi mom"}); Using MessageBus and a custom EventArgs class lets me have an application wide message sink for a specific type of message. This comes in handy when you have several forms that, for example, display customer information and maybe a couple forms that update that information. None of the forms know about each other and none of them need to be wired to a static "super class". I have a couple questions: fxCop complains about using static methods with generics, but this is exactly what I'm after here. I want there to be exactly one MessageBus for each type of message handled. Using a static with a generic saves me from writing all the code that would maintain the list of MessageBus objects. Are the listening objects being kept "alive" via the MessageReceived event? For instance, perhaps I have this code in a Form.Load event: MessageBus<CustomerChangedEventArgs>.MessageReceived += (s,e) => DoReload(); When the Form is Closed, is the Form being retained in memory because MessageReceived has a reference to its DoReload method? Should I be removing the reference when the form closes: MessageBus<CustomerChangedEventArgs>.MessageReceived -= (s,e) => DoReload();

    Read the article

  • Computing "average" of two colors

    - by Francisco P.
    This is only marginally programming related - has much more to do w/ colors and their representation. I am working on a very low level app. I have an array of bytes in memory. Those are characters. They were rendered with anti-aliasing: they have values from 0 to 255, 0 being fully transparent and 255 totally opaque (alpha, if you wish). I am having trouble conceiving an algorithm for the rendering of this font. I'm doing the following for each pixel: // intensity is the weight I talked about: 0 to 255 intensity = glyphs[text[i]][x + GLYPH_WIDTH*y]; if (intensity == 255) continue; // Don't draw it, fully transparent else if (intensity == 0) setPixel(x + xi, y + yi, color, base); // Fully opaque, can draw original color else { // Here's the tricky part // Get the pixel in the destination for averaging purposes pixel = getPixel(x + xi, y + yi, base); // transfer is an int for calculations transfer = (int) ((float)((float) (255.0 - (float) intensity/255.0) * (float) color.red + (float) pixel.red)/2); // This is my attempt at averaging newPixel.red = (Byte) transfer; transfer = (int) ((float)((float) (255.0 - (float) intensity/255.0) * (float) color.green + (float) pixel.green)/2); newPixel.green = (Byte) transfer; // transfer = (int) ((float) ((float) 255.0 - (float) intensity)/255.0 * (((float) color.blue) + (float) pixel.blue)/2); transfer = (int) ((float)((float) (255.0 - (float) intensity/255.0) * (float) color.blue + (float) pixel.blue)/2); newPixel.blue = (Byte) transfer; // Set the newpixel in the desired mem. position setPixel(x+xi, y+yi, newPixel, base); } The results, as you can see, are less than desirable. That is a very zoomed in image, at 1:1 scale it looks like the text has a green "aura". Any idea for how to properly compute this would be greatly appreciated. Thanks for your time!

    Read the article

  • Segmentation in Linux : Segmentation & Paging are redundant?

    - by claws
    Hello, I'm reading "Understanding Linux Kernel". This is the snippet that explains how Linux uses Segmentation which I didn't understand. Segmentation has been included in 80 x 86 microprocessors to encourage programmers to split their applications into logically related entities, such as subroutines or global and local data areas. However, Linux uses segmentation in a very limited way. In fact, segmentation and paging are somewhat redundant, because both can be used to separate the physical address spaces of processes: segmentation can assign a different linear address space to each process, while paging can map the same linear address space into different physical address spaces. Linux prefers paging to segmentation for the following reasons: Memory management is simpler when all processes use the same segment register values that is, when they share the same set of linear addresses. One of the design objectives of Linux is portability to a wide range of architectures; RISC architectures in particular have limited support for segmentation. All Linux processes running in User Mode use the same pair of segments to address instructions and data. These segments are called user code segment and user data segment , respectively. Similarly, all Linux processes running in Kernel Mode use the same pair of segments to address instructions and data: they are called kernel code segment and kernel data segment , respectively. Table 2-3 shows the values of the Segment Descriptor fields for these four crucial segments. I'm unable to understand 1st and last paragraph.

    Read the article

  • Associating an object with another object for GC clearup

    - by thecoop
    Is there any way of associating an object instance (object A) with a second object (object B) in a generalised way, so that when B gets collected A becomes eligable for collection? The same behaviour that would happen if B had an instance variable pointing to A, but without explicitly changing the class definition of B, and being able to do this in a dynamic way? The same sort of effect could be done by using the Component.Disposed event in a funky way, but I don't want to make B disposable EDIT I'm basically creating a cache of objects that are associated with a single 'root' object, and I don't want the cache to be static, as there can be lots of root objects using different caches, so lots of memory will be used up when a root object is no longer used but the cached objects are still around. So, I want a collection of cached objects to be associated with each 'root' object, without changing the root object definition. Sort of like metadata of an extra object reference attached to each root object instance. That way, each collection will get collected when the root object is collected, and not hang around like they would if a static cache was used.

    Read the article

  • CSS Background image in Redmine template arbitrarily not loading

    - by Pekka
    I`m in the process of building a template for Redmine (a project management system based on Ruby on Rails.) Ruby is running on a virtual server from a Bitnami.org installation package. The OS is Windows. The template essentially consists of a styles.css file. In that file, I have the following line: #header { padding: 0px; padding-top: 48px; background-color: #62DFFF; background-image: url(../images/bkg.jpg) background-position: center bottom; background-repeat: repeat-x; height:150px; } It's a header element with a background image. The problem: This background image arbitrarily appears and disappears when reloading. Say you reload ten times in twenty seconds; the image will appear in two instances, and be missing in the 18 others. I would have put this down to server problems, but the weird thing is that when it's missing, the request for the image doesn't appear in Firebug's net tab at all. Even if it were cached, the request should be there. Raw screenshots of the identical page on two reloads: I am 100% sure the CSS file does not change in between. I have examined both instances with Firebug and the CSS is identical. It happens in both Firefox and Chrome so it must be something basic I'm overlooking. What could be causing a browser not to load a resource at all? I have zero idea about Ruby nor Rails - getting Redmine running and customized is all I have ever had to do with this platform - so I don't really know where to look. Apache's, Mongrel's and Redmine's error logs look fine, though.

    Read the article

  • Thoughts on GoGrid vs EC2

    - by Jason
    I am currently hosting my SaaS application at GoGrid (Microsoft stack). Here's what I have: Database Server - physical box, 12 GB RAM, 2 X Quad Core CPU (2.13 GHz Xeon E5506) 2 Web / App servers - cloud servers, 2 GB RAM, 2 VCPUs 300 GB monthly bandwidth I am paying around $900 / month for this. My web / app servers are busting at the seams and need to be upgraded to 4 GB of RAM. I also need a firewall, and GoGrid just added this service for an additional $200. After the upgrade, I will be paying around $1,400. I started looking at Amazon EC2, specifically this config: Database server - "High Memory Double Extra Large Instance" - 34 GB RAM, 13 EC2 compute units 2 Web / App servers - "Large Instance" - 7.5 GB RAM, 4 EC2 compute units If I go with 1 year reserved instances, my upfront cost would be $4,500 and my monthly would be $700. This comes to $1,075 / month when amortized. Amazon also includes a firewall for free. Here are my questions: Do any of you have experience running a database (especially SQL Server) on an EC2 instance? How did it perform compared to a dedicated machine? One of my major concerns is with disk I/O. Amazon's description of a compute unit is fairly vague. Any ideas on how the CPU performance on the database servers would compare? I am hoping that the Amazon solution will provide significantly better performance than my current or even improved GoGrid setup. Having a virtual database server would also be nice in terms of availability. Right now I would be in serious trouble if I had any hardware issues. Thanks for any insight...

    Read the article

  • Guid Primary /Foreign Key dilemma SQL Server

    - by Xience
    Hi guys, I am faced with the dilemma of changing my primary keys from int identities to Guid. I'll put my problem straight up. It's a typical Retail management app, with POS and back office functionality. Has about 100 tables. The database synchronizes with other databases and receives/ sends new data. Most tables don't have frequent inserts, updates or select statements executing on them. However, some do have frequent inserts and selects on them, eg. products and orders tables. Some tables have upto 4 foreign keys in them. If i changed my primary keys from 'int' to 'Guid', would there be a performance issue when inserting or querying data from tables that have many foreign keys. I know people have said that indexes will be fragmented and 16 bytes is an issue. Space wouldn't be an issue in my case and apparently index fragmentation can also be taken care of using 'NEWSEQUENTIALID()' function. Can someone tell me, from there experience, if Guid will be problematic in tables with many foreign keys. I'll be much appreciative of your thoughts on it...

    Read the article

  • Problem saving file on Motorola Droid, Android 2.1?

    - by Rob Kent
    Two of my users have reported a problem with my Android application, OftSeen Gestures. Both of them are using a Motorola Droid. The app saves a text file which is just a list of gesture names and phone numbers, both strings. It saves the file to the private data area. I don't know that it is this code that is failing but they report the assigned numbers disappearing after the phone comes out of screen sleep. Since the file is reread in OnCreate each time, I'm assuming the file doesn't exist on return. As soon as I can get my hands on a Droid I will debug it but in the meantime can you see a reason why this save operation would fail on Droid (no other users have reported this)? OutputStreamWriter out = new OutputStreamWriter(AppGlobal.getContext().openFileOutput(MAPPINGS_FILE_NAME, 0)); for (String key : mMap.keySet()) { String number = mMap.get(key).number; out.write(String.format("%s,%s\n", key, number == null ? "" : number)); } out.close(); AppGlobal.getContext returns the application context and the MAPPINGS_FILE_NAME resolves to "gesture_mappings.txt". Like I say, I don't know that this is the problem. It could be something else to do with state management inside the app. If anyone has a Droid, maybe they could download the app from Market and test it for me? Note this is a genuine request for help - not an attempt to increase my downloads.

    Read the article

  • How to accommodate for the iPhone 4 screen resolution?

    - by dontWatchMyProfile
    This is a programming question! Read on before you vote to close! According to Apple, the iPhone 4 has a new and better screen resolution: 3.5-inch (diagonal) widescreen Multi-Touch display 960-by-640-pixel resolution at 326 ppi This little detail affects our apps in a heavy way. Most of the demo apps on the net have one thing in common: They position views in the believe that the screen has a fixed size of 320 x 480 pixels. So what most -if not all- developers do is: They designed everything in such a way, that a touchable area is -for example- 50 x 50 pixels big. Just enough to tap it. Things have been positioned relative to the upper left, to reach a specific position on screen - let's say the center, or somewhere at the bottom. Edit: It seems Apple has integrated an switch that allows to tell if an app is highRes or not. Nice. When we develop high-resolution apps, they probably won't work on older devices. And if they do, they would suffer a lot from 4-times the size of any image, having to scale them down in memory.

    Read the article

  • Trouble with Unions in C program.

    - by Jordan S
    I am working on a C program that uses a Union. The union definition is in FILE_A header file and looks like this... // FILE_A.h**************************************************** xdata union { long position; char bytes[4]; }CurrentPosition; If I set the value of CurrentPosition.position in FILE_A.c and then call a function in FILE_B.c that uses the union, the data in the union is back to Zero. This is demonstrated below. // FILE_A.c**************************************************** int main.c(void) { CurrentPosition.position = 12345; SomeFunctionInFileB(); } // FILE_B.c**************************************************** void SomeFunctionInFileB(void) { // After the following lines execute I see all zeros in the flash memory. WriteByteToFlash(CurrentPosition.bytes[0]; WriteByteToFlash(CurrentPosition.bytes[1]; WriteByteToFlash(CurrentPosition.bytes[2]; WriteByteToFlash(CurrentPosition.bytes[3]; } Now, If I pass a long to SomeFunctionInFileB(long temp) and then store it into CurrentPosition.bytes within that function, and finally call WriteBytesToFlash(CurrentPosition.bytes[n]... it works just fine. It appears as though the CurrentPosition Union is not global. So I tried changing the union definition in the header file to include the extern keyword like this... extern xdata union { long position; char bytes[4]; }CurrentPosition; and then putting this in the source (.c) file... xdata union { long position; char bytes[4]; }CurrentPosition; but this causes a compile error that says: C:\SiLabs\Optec Programs\AgosRot\MotionControl.c:76: error 91: extern definition for 'CurrentPosition' mismatches with declaration. C:\SiLabs\Optec Programs\AgosRot\/MotionControl.h:48: error 177: previously defined here So what am I doing wrong? How do I make the union global?

    Read the article

  • Several Objective-C objects become Invalid for no reason, sometimes.

    - by farnsworth
    - (void)loadLocations { NSString *url = @"<URL to a text file>"; NSStringEncoding enc = NSUTF8StringEncoding; NSString *locationString = [[NSString alloc] initWithContentsOfURL:[NSURL URLWithString:url] usedEncoding:&enc error:nil]; NSArray *lines = [locationString componentsSeparatedByString:@"\n"]; for (int i=0; i<[lines count]; i++) { NSString *line = [lines objectAtIndex:i]; NSArray *components = [line componentsSeparatedByString:@", "]; Restaurant *res = [byID objectForKey:[components objectAtIndex:0]]; if (res) { NSString *resAddress = [components objectAtIndex:3]; NSArray *loc = [NSArray arrayWithObjects:[components objectAtIndex:1], [components objectAtIndex:2]]; [res.locationCoords setObject:loc forKey:resAddress]; } else { NSLog([[components objectAtIndex:0] stringByAppendingString:@" res id not found."]); } } } There are a few weird things happening here. First, at the two lines where the NSArray lines is used, this message is printed to the console- *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSCFDictionary count]: method sent to an uninitialized mutable dictionary object' which is strange since lines is definitely not an NSMutableDictionary, definitely is initialized, and because the app doesn't crash. Also, at random points in the loop, all of the variables that the debugger can see will become Invalid. Local variables, property variables, everything. Then after a couple lines they will go back to their original values. setObject:forKey never has an effect on res.locationCoords, which is an NSMutableDictionary. I'm sure that res, res.locationCoords, and byId are initialized. I also tried adding a retain or copy to lines, same thing. I'm sure there's a basic memory management principle I'm missing here but I'm at a loss.

    Read the article

  • How can I tackle 'profoundly found elsewhere' syndrome (inverse of NIH)?

    - by Alistair Knock
    How can I encourage colleagues to embrace small-scale innovation within our team(s), in order to get things done quicker and to encourage skills development? (the term 'profoundly found elsewhere' comes from Wikipedia, although it is scarcely used anywhere else apart from a reference to Proctor & Gamble) I've worked in both environments where there is a strong opposition to software which hasn't been developed in-house (usually because there's a large community of developers), and more recently (with far fewer central developers) where off-the-shelf products are far more favoured for the usual reasons: maintenance, total cost over product lifecycle, risk management and so on. I think the off the shelf argument works in the majority of cases for the majority of users, even though as a developer the product never quite does what I'd like it to do. However, in some cases there are clear gaps where the market isn't able to provide specifically what we would need, or at least it isn't able to without charging astronomical consultancy rates for a bespoke solution. These can be small web applications which provide a short-term solution to a particular need in one specific department, or could be larger developments that have the potential to serve a wider audience, both across the organisation and into external markets. The problem is that while development of these applications would be incredibly cheap in terms of developer hours, and delivered very quickly without the need for glacial consultation, the proposal usually falls flat because of risk: 'Who'll maintain the project tracker that hasn't had any maintenance for the past 7 years while you're on holiday for 2 weeks?' 'What if one of our systems changes and the connector breaks?' 'How can you guarantee it's secure/better/faster/cheaper/holier than Company X's?' With one developer behind these little projects, the answers are invariably: 'Nobody, but...' 'It will break, just like any other application would...' 'I, uh...' How can I better answer these questions and encourage people to take a little risk in order to stimulate creativity and fast-paced, short-lifecycle development instead of using that 6 months to consult about what tender process we might use?

    Read the article

  • When do instance variables get initialized and values assigned?

    - by AKh
    When doees the instance variable get initialized? Is it after the constructor block is done or before it? Consider this example: public abstract class Parent { public Parent(){ System.out.println("Parent Constructor"); init(); } public void init(){ System.out.println("parent Init()"); } } public class Child extends Parent { private Integer attribute1; private Integer attribute2 = null; public Child(){ super(); System.out.println("Child Constructor"); } public void init(){ System.out.println("Child init()"); super.init(); attribute1 = new Integer(100); attribute2 = new Integer(200); } public void print(){ System.out.println("attribute 1 : " +attribute1); System.out.println("attribute 2 : " +attribute2); } } public class Tester { public static void main(String[] args) { Parent c = new Child(); ((Child)c).print(); } } OUTPUT: Parent Constructor Child init() parent Init() Child Constructor attribute 1 : 100 attribute 2 : null When the memory for the atribute 1 & 2 are allocated in the heap ? Curious to know why is attribute 2 is NULL ? Are there any design flaws?

    Read the article

  • Winsock WSAAsyncSelect sending without an infinite buffer

    - by Xexr
    Hi, This is more of a design question than a specific code question, I'm sure I am missing the obvious, I just need another set of eyes. I am writing a multi-client server based on WSAAsyncSelect, each connection is made into an object of a connection class I have written which contains associated settings and buffers etc. My question concerns FD_WRITE, I understand how it operates: One FD_WRITE is sent immediately after a connection is established. Thereafter, you should send until WSAEWOULDBLOCK is received at which point you store what is left to send in a buffer, and wait to be told that it is ok to send again. This is where I have a problem, how large do I make this holding buffer within each connections object? The amount of time until a new FD_WRITE is received is unknown, I could be attempting to send a lot of stuff during this period, all the time adding to my outgoing buffer. If I make the buffer dynamic, memory usage could spiral out of control if for whatever reason, I am unable to send() and reduce the buffer. So my question is how do you generally handle this situation? Note I am not talking about the network buffer itself which winsock uses, but one of my own creation used to "queue" up sends. Hope I explained that well enough, thanks all!

    Read the article

  • Please critique this method

    - by Jakob
    Hi I've been looking around the net for some tab button close functionality, but all those solutions had some complicated eventhandler, and i wanted to try and keep it simple, but I might have broken good code ethics doing so, so please review this method and tell me what is wrong. public void AddCloseItem(string header, object content){ //Create tabitem with header and content StackPanel headerPanel = new StackPanel() { Orientation = Orientation.Horizontal, Height = 14}; headerPanel.Children.Add(new TextBlock() { Text = header }); Button closeBtn = new Button() { Content = new Image() { Source = new BitmapImage(new Uri("images/cross.png", UriKind.Relative)) }, Margin = new Thickness() { Left = 10 } }; headerPanel.Children.Add(closeBtn); TabItem newTabItem = new TabItem() { Header = headerPanel, Content = content }; //Add close button functionality closeBtn.Tag = newTabItem; closeBtn.Click += new RoutedEventHandler(closeBtn_Click); //Add item to list this.Add(newTabItem); } void closeBtn_Click(object sender, RoutedEventArgs e) { this.Remove((TabItem)((Button)sender).Tag); } So what I'm doing is storing the tabitem in the btn.Tag property, and then when the button is clicked i just remove the tabitem from my observablecollection, and the UI is updated appropriately. Am I using too much memory saving the tabitem to the Tag property?

    Read the article

  • Execute Stored Procedure from Classic ASP

    - by Jaco Pretorius
    For some fantastic reason I find myself debugging a problem in a Classic ASP page (at least 10 years of my life lost in the last 2 days). I'm trying to execute a stored procedure which contains some OUT parameters. The problem is that one of the OUT parameters is not being populated when the stored procedure returns. I can execute the stored proc from SQL management studio (this is 2008) and all the values are being set and returned exactly as expected. declare @inVar1 varchar(255) declare @inVar2 varchar(255) declare @outVar1 varchar(255) declare @outVar2 varchar(255) SET @inVar2 = 'someValue' exec theStoredProc @inVar1 , @inVar2 , @outVar1 OUT, @outVar2 OUT print '@outVar1=' + @outVar1 print '@outVar2=' + @outVar2 Works great. Fantastic. Perfect. The exact values that I'm expecting are being returned and printed out. Right, since I'm trying to debug a Classic ASP page I copied the code into a VBScript file to try and narrow down the problem. Here is what I came up with: Set Conn = CreateObject("ADODB.Connection") Conn.Open "xxx" Set objCommandSec = CreateObject("ADODB.Command") objCommandSec.ActiveConnection = Conn objCommandSec.CommandType = 4 objCommandSec.CommandText = "theStoredProc " objCommandSec.Parameters.Refresh objCommandSec.Parameters(2) = "someValue" objCommandSec.Execute MsgBox(objCommandSec.Parameters(3)) Doesn't work. Not even a little bit. (Another ten years of my life down the drain) The third parameter is simply NULL - which is what I'm experiencing in the Classic ASP page as well. Could someone shed some light on this? Am I completely daft for thinking that the classic ASP code would be the same as the VBScript code? I think it's using the same scripting engine and syntax so I should be ok, but I'm not 100% sure. The result I'm seeing from my VBScript is the same as I'm seeing in ASP.

    Read the article

  • Loading Jscript files into Firefox extension

    - by colon3l
    Hi ! Let's get directly to the problem : I'm actually doing a firefox extension in which i would like to implement the jWebsocket API in order to build a small chat. I got my main script file, named test.js, and the jWebsocket lib into a js folder. Just for you to know, this is my first firefox extension ever. So in my XUL file I got this (for the script part only of course, the interface code is not shown) : <overlay id="test-overlay" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"> <script type="application/x-javascript" src="chrome://test/content/test.js" /> <script type="application/x-javascript" src="chrome://test/content/js/jwebsocket.js" /> jwebsocket.js being the file I need to call according to jWebsocket website. In my main script file test.js I start with : if (jws.browserSupportsWebSockets()) { jWebSocketClient = new jws.jWebSocketJSONClient(); } else { var lMsg = jws.MSG_WS_NOT_SUPPORTED; alert(lMsg); } jws being the namespace created into the jwebsocket.js file. Of course I've got the required stand-alone server running in background, and working. So from what I understood looking on various websites, is that if a js file is loaded into the javascript allocated memory space (with the tag), all namespace/function should be available between each file. But this was mostly for HTML-oriented issues, so I'm not sure if it applies to XUL/Firefox environment. But the script keep failing at the first jws call. Any ideas on what goes wrong here ? I'm stuck for 2 days now :/

    Read the article

  • How to best future proof my application that needs to connect to Outlook?

    - by Troy
    I have a contact management application written in Delphi which has a “Sync with Outlook” feature that I developed 10 years ago. Now, I’m going back to add some features and fix some bugs. This sync feature uses the Outlook object model to get started, but it has an optional mode called “Use MAPI Enhancements” where it uses pure MAPI to speed up how it looks for changes, and it allows notes to be synced w/ RTF instead of just plain text. I'm wondering if supporting two parallel paths of execution is a good idea or not. If I went with all MAPI, I believe I'd avoid some security prompts, and I'd avoid situations where anti-virus has "script-blocking" features which block my app from connecting to Outlook. But I believe that on the down side, my 32-bit app would not be able to to connect with 64-bit Outlook 2010 using MAPI. And I wonder about the future of MAPI in general. If I stick with the Outlook object model, will my 32-bit app be able to connect to the Outlook object model (since it's out of process COM)? If so, this is a compelling reason to keep my Outlook object model execution path in place. But if not, and if my app needs to be compiled for x64, then why not just go with pure MAPI?

    Read the article

  • Why Android for enterprise applications?

    - by mcabral
    Recently one of our clients is considering the posibility of picking up an old WinMobile 5.0 project. Several features are to be added to the point it will be a major version update. The client is worried about the mobile market, and thinks there's a chance all the effort put in this development will have to be thrown away in a couple of year due to the dinamics of the mobile market and the deprecation of mobile devices. So, the client is not sure whether he should continue with Windows Mobile (changing from WM 5.0 to 6.X) or starting from scratch with another technology. From our part we have been studing the mobile market, looking for clues for which will be the winning horse. The safe move seems to continue with WM just because re writing an entire application from scratch involves more risks and delays. On the other hand WM seems to be losing market and the ghost of an exit on their part is growing stronger everyday. But what can be say about Android? Everyone is talking about it and is growing at full speed but what avantagies will it bring to the table? Why should we start a fresh applicaction on this technology? So the question remains the same.. is Andriod mature enough for an enterprise application? Will you recomend it to one of your clients? Will you port/rewrite a WM application to Andriod? What's the trade-off? EDIT: Addressing commentaries. The app is entirely built with C# and Compact Framework. The app is for logistics/management.

    Read the article

< Previous Page | 812 813 814 815 816 817 818 819 820 821 822 823  | Next Page >