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  • ListView with button and check mark?

    - by jgelderloos
    So I have looked through a lot of other answers but have not been able to get my app to work how I want it. I basically want the list view that has the text and check mark to the right, but then an addition button to the left. Right now my list view shows up but the check image is never changed. Selector: <?xml version="1.0" encoding="utf-8"?> <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_selected="true" android:drawable="@drawable/accept_on" /> <item android:drawable="@drawable/accept" /> </selector> Row xml: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/layout" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="10dp" android:background="#EEE"> <ImageButton android:id="@+id/goToMapButton" android:src="@drawable/go_to_map" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="left" /> <TextView android:id="@+id/itemName" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center_vertical" android:textColor="#000000" android:layout_marginTop="5dp" android:layout_marginBottom="5dp" android:layout_weight="1" /> <Button android:id="@+id/checkButton" android:background="@drawable/item_selector" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="right" /> </LinearLayout> MapAdapter: import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.ImageButton; import android.widget.LinearLayout; import android.widget.TextView; public class MapAdapter extends ArrayAdapter<String>{ Context context; int layoutResourceId; String data[] = null; LayoutInflater inflater; LinearLayout layout; public MapAdapter(Context context, int layoutResourceId, String[] data) { super(context, layoutResourceId, data); this.layoutResourceId = layoutResourceId; this.context = context; this.data = data; inflater = LayoutInflater.from(context); } @Override public String getItem(int position) { return data[position]; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = new ViewHolder(); if(convertView == null) { convertView = inflater.inflate(R.layout.map_item_row, null); layout = (LinearLayout)convertView.findViewById(R.id.layout); holder.map = (ImageButton)convertView.findViewById(R.id.goToMapButton); holder.name = (TextView)convertView.findViewById(R.id.itemName); //holder.check = (Button)convertView.findViewById(R.id.checkButton); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } layout.setBackgroundColor(0x00000004); holder.name.setText(getItem(position)); return convertView; } static class ViewHolder { ImageButton map; TextView name; Button check; } }

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  • A format for storing personal contacts in a database

    - by Gart
    I'm thinking of the best way to store personal contacts in a database for a business application. The traditional and straightforward approach would be to create a table with columns for each element, i.e. Name, Telephone Number, Job title, Address, etc... However, there are known industry standards for this kind of data, like for example vCard, or hCard, or vCard-RDF/XML or even Windows Contacts XML Schema. Utilizing an standard format would offer some benefits, like inter-operablilty with other systems. But how can I decide which method to use? The requirements are mainly to store the data. Search and ordering queries are highly unlikely but possible. The volume of the data is 100,000 records at maximum. My database engine supports native XML columns. I have been thinking to use some XML-based format to store the personal contacts. Then it will be possible to utilize XML indexes on this data, if searching and ordering is needed. Is this a good approach? Which contacts format and schema would you recommend for this? Edited after first answers Here is why I think the straightforward approach is bad. This is due to the nature of this kind of data - it is not that simple. The personal contacts it is not well-structured data, it may be called semi-structured. Each contact may have different data fields, maybe even such fields which I cannot anticipate. In my opinion, each piece of this data should be treated as important information, i.e. no piece of data could be discarded just because there was no relevant column in the database. If we took it further, assuming that no data may be lost, then we could create a big text column named Comment or Description or Other and put there everything which cannot be fitted well into table columns. But then again - the data would lose structure - this might be bad. If we wanted structured data then - according to the database design principles - the data should be decomposed into entities, and relations should be established between the entities. But this adds complexity - there are just too many entities, and lots of design desicions should be made, like "How do we store Address? Personal Name? Phone number? How do we encode home phone numbers and mobile phone numbers? How about other contact info?.." The relations between entities are complex and multiple, and each relation is a table in the database. Each relation needs to be documented in the design papers. That is a lot of work to do. But it is possible to avoid the complexity entirely - just document that the data is stored according to such and such standard schema, period. Then anybody who would be reading that document should easily understand what it was all about. Finally, this is all about using an industry standard. The standard is, hopefully, designed by some clever people who anticipated and described the structure of personal contacts information much better than I ever could. Why should we all reinvent the wheel?? It's much easier to use a standard schema. The problem is, there are just too many standards - it's not easy to decide which one to use!

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  • Implementing a robust async stream reader

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output, but that is a detail and does not play an important role. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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  • C# Accessing controls from an outside class without "public"

    - by Kurt W
    I know this has been asked before but I believe my situation is a bit different -- or I don't understand the answers given. I have spent about 4 hours working on this solidly and finally realized, I just don't know what to do. I have 2 Forms (Form1, Settings) and a class I created called Themes. I have get/set properties that currently work but are all within Form1 and I would like to move as much code related to themeing as I can OUTSIDE of Form1 and into Themes.cs. Changing Theme: To change the theme, the user opens up the Settings form and selects a theme from the dropdown menu and presses the 'Set' button -- this all works, but now I want to move it into my own class and I can't get the code to compile. Here is example code that works before moving -- note that this is only 2 different controls I want to modify but there are about 30 total. I am abridging the code: Form 1: public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void btnSettings_Click(object sender, EventArgs e) { Settings frm = new Settings(this); frm.Show(); } private Color txtRSSURLBGProperty; private Color txtRSSURLFGProperty; public Color TxtRSSURLBGProperty { get { return txtRSSURLBGProperty; } set { txtRSSURL.BackColor = value; } } public Color TxtRSSURLFGProperty { get { return txtRSSURLFGProperty; } set { txtRSSURL.ForeColor = value; } } Settings Form: public partial class Settings : Form { public Settings() { InitializeComponent(); } private Form1 rssReaderMain = null; public Settings(Form requestingForm) { rssReaderMain = requestingForm as Form1; InitializeComponent(); } private void button2_Click(object sender, EventArgs args) { // Appearence settings for DEFAULT THEME if (cbThemeSelect.SelectedIndex == 1) { this.rssReaderMain.TxtRSSURLBGProperty = Color.DarkSeaGreen; this.rssReaderMain.TxtRSSURLFGProperty = Color.White; [......about 25 more of these....] } The theme class is currently empty. Again, the goal is to move as much code into the themes class (specifically the get/set statements if at all possible!) and hopefully just use a method similar to this within the Settings form once the proper drowndown item is selected: SetTheme(Default); I hope someone can help, and I hope I explained it right! I have been racking my brain and I need to have this done fairly soon! Much thanks in advance as I'm sure everyone says. I have teamviewer or logmein if someone wants to remote in -- that is just as easy. I can also send my project as a zip if needed. Thanks so much, Kurt Modified code for review: Form1 form: public partial class Form1 : ThemeableForm { public Form1() { InitializeComponent(); } ThemeableForm form: internal abstract class ThemeableForm : Form { private Color rssLabelBGProperty; private Color rssLabelFGProperty; public Color RssLabelBGProperty { get { return rssLabelBGProperty; } set { lRSS.BackColor = value; } } public Color RssLabelFGProperty { get { return rssLabelFGProperty; } set { lRSS.ForeColor = value; } } Settings form: public Settings(ThemeableForm requestingForm) { rssReaderMain = requestingForm as ThemeableForm; InitializeComponent(); } private ThemeableForm rssReaderMain = null; private void button2_Click(object sender, EventArgs args) { // Appearence settings for DEFAULT THEME if (cbThemeSelect.SelectedIndex == 1) { this.rssReaderMain.LRSSBGProperty = Color.DarkSeaGreen; this.rssReaderMain.LRSSFGProperty = Color.White; } Now the all the controls in my get/set (lRSS in the example code above) error out with does not exist in the current context. I also get the warning: Warning 1The designer could not be shown for this file because none of the classes within it can be designed. The designer inspected the following classes in the file: Form1 --- The base class 'RSSReader_BKRF.ThemeableForm' could not be loaded. Ensure the assembly has been referenced and that all projects have been built. 0 0

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  • Installing Windows on HP Proliant Servers without SmartStart

    - by Fitzroy
    I have a PXE server for deploying Windows XP and Windows 7 to workstations. The process is as follows: Boot the workstation from the NIC. Workstation sends a DHCP request. DHCP server responds with an IP address and the location of the PXE server. Workstation downloads WinPE image file from PXE server via TFTP Workstation stores WinPE image file in memory and executes it. Once booted into WinPE, I connect to a network share to gain access to either the Windows XP or Windows 7 installation files. A custom script is launched to guide you through the process of formatting and partitioning the hard drive(s) (using DISKPART and FORMAT). Another custom script asks for details such as the hostname to assign to the workstation. The answers provided are used to build an unattended answer file (SIF [Setup Information File] for WinXP and XML for Win7). The Windows setup EXE is launched, passing the unattended answer file to it as a parameter. The Windows XP and Windows 7 installation sources have been customised to include the drivers for our Dell workstations. They also run a number of scripts upon first booting up to install software packages. This process works very well for our workstations and I would now like to use it for building our servers too. The vast majority of our servers are HP Proliant DL360 G6, DL380 G5 and DL380 G6. They’re running Windows Server 2003 (various editions) or 2008 (various editions). To date, we have always built the HP Proliant servers using the SmartStart CD provided. SmartStart does three useful things for us: Setup RAID with HP Array Configuration Utility (ACU). Installs and configures SNMP Installs various HP Tools for Windows (HP Array Configuration Utility, HP Array Diagnostic Utility, HP Proliant Integrated Management Log Viewer, etc) Using SmartStart I have never had to manually download and install Windows drivers for network, sound, video, etc. I'm not sure if this is because SmartStart copies drivers from the CD during setup, or whether Windows just has the drivers natively in its driver CAB. If I abandon the SmartStart CD in favour of my PXE server I would have to do the following: As I wont have access to ACU, I'll configure the RAID (before booting to the PXE server) by pressing F8 (during the boot process) to access Option ROM Configuration for Arrays (ORCA). Installation of SNMP and the HP Tools will have to be installed once the Windows installation is complete using the Proliant Support Pack. Is this method OK? Is there anything that the SmartStart CD does that I'll be unable to do by other means? Are there any disadvantages to not using the SmartStart CD? Many thanks. UPDATE 05/01/12 I’ve been reading through the SmartStart Scripting Toolkit documentation. The scripting toolkit contains command line tools which work within WinPE and can such things as configure BIOS settings, configure an array and setup ILO. I’m personally not too bothered about configuring BIOS settings as I rarely deviate from the defaults (unless the server is to be a Hyper-V host). I’m not too fussed about being able to configure the array from within WinPE, as I’m happy to just press F8 and use Option ROM Configuration for Arrays (ORCA). Although, if it’s easy enough to do, I will explore this further, as it saves time if everything can be configured from within WinPE. One of the nice features all the tools possess is that you can pass input files to them. EG. Configure one server to your requirements, capture its configuration to a file (using the appropriate tool), you can then use the tool on other servers passing the input file with the captured configuration. Array controller drivers appear to be included with the toolkit along with example of how to incorporate them within a WinPE build. I suppose WinPE won’t be able to see logical volumes (I.E 2x physical disks in a RAID 1 configuration) without the array controller drivers? I mentioned in my post that SmartStart normally installs a bunch of Windows HP tools for you. I’ve had a look today, and if you run the SmartStart CD from within Windows all the tools can be installed. Therefore I can do this after the Windows installation is complete. The SmartStart CD appears to contain a lot Windows drivers. I can customise my Windows 2008 source to incorporate these drivers. However, I understand that incorporating an array controller driver is a little different to most drivers. I believe that you have to provide the driver during the very early stages of the Windows setup. I’m working through the Scripting Toolkit documentation to try and work this out...

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  • Minimum-Waste Print Job Grouping Algorithm?

    - by Matt Mc
    I work at a publishing house and I am setting up one of our presses for "ganging", in other words, printing multiple jobs simultaneously. Given that different print jobs can have different quantities, and anywhere from 1 to 20 jobs might need to be considered at a time, the problem would be to determine which jobs to group together to minimize waste (waste coming from over-printing on smaller-quantity jobs in a given set, that is). Given the following stable data: All jobs are equal in terms of spatial size--placement on paper doesn't come into consideration. There are three "lanes", meaning that three jobs can be printed simultaneously. Ideally, each lane has one job. Part of the problem is minimizing how many lanes each job is run on. If necessary, one job could be run on two lanes, with a second job on the third lane. The "grouping" waste from a given set of jobs (let's say the quantities of them are x, y and z) would be the highest number minus the two lower numbers. So if x is the higher number, the grouping waste would be (x - y) + (x - z). Otherwise stated, waste is produced by printing job Y and Z (in excess of their quantities) up to the quantity of X. The grouping waste would be a qualifier for the given set, meaning it could not exceed a certain quantity or the job would simply be printed alone. So the question is stated: how to determine which sets of jobs are grouped together, out of any given number of jobs, based on the qualifiers of 1) Three similar quantities OR 2) Two quantities where one is approximately double the other, AND with the aim of minimal total grouping waste across the various sets. (Edit) Quantity Information: Typical job quantities can be from 150 to 350 on foreign languages, or 500 to 1000 on English print runs. This data can be used to set up some scenarios for an algorithm. For example, let's say you had 5 jobs: 1000, 500, 500, 450, 250 By looking at it, I can see a couple of answers. Obviously (1000/500/500) is not efficient as you'll have a grouping waste of 1000. (500/500/450) is better as you'll have a waste of 50, but then you run (1000) and (250) alone. But you could also run (1000/500) with 1000 on two lanes, (500/250) with 500 on two lanes and then (450) alone. In terms of trade-offs for lane minimization vs. wastage, we could say that any grouping waste over 200 is excessive. (End Edit) ...Needless to say, quite a problem. (For me.) I am a moderately skilled programmer but I do not have much familiarity with algorithms and I am not fully studied in the mathematics of the area. I'm I/P writing a sort of brute-force program that simply tries all options, neglecting any option tree that seems to have excessive grouping waste. However, I can't help but hope there's an easier and more efficient method. I've looked at various websites trying to find out more about algorithms in general and have been slogging my way through the symbology, but it's slow going. Unfortunately, Wikipedia's articles on the subject are very cross-dependent and it's difficult to find an "in". The only thing I've been able to really find would seem to be a definition of the rough type of algorithm I need: "Exclusive Distance Clustering", one-dimensionally speaking. I did look at what seems to be the popularly referred-to algorithm on this site, the Bin Packing one, but I was unable to see exactly how it would work with my problem. Any help is appreciated. :)

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  • Remote host: can tracert, can telnet, can*not* browse: what gives?

    - by MacThePenguin
    One of my customers of the company I work for has made a change to their Internet connection, and now we can't connect to them any more from our LAN. To help me troubleshoot this issue, the network guy on the customer's site has configured their firewall so that a HTTPS connection to their public IP address is open to any IP. I should put https://<customer's IP> in my browser and get a web page. Well, it works from any network I've tried (even from my smartphone), just not from my company's LAN. I thought it may be an issue with our firewall (though I checked its rules and it allows outbound TCP port 443 to anywhere), so I just connected a PC directly to the network connection of our provider, bypassing out firewall completely, and still it didn't work (everything else worked). So I asked for help to our Internet provider's customer service, and they asked me to do a tracert to our customer's IP. The tracert is successful, as the final hop shown in the output is the host I want to reach. So they said there's no problem. :( I also tried telnet <customer's IP> 443 and that works as well: I get a blank page with the cursor blinking (I've tried using another random port and that gives me an error message, as it should). Still, from any browser of any PC in my LAN I can't open that URL. I tried checking the network traffic with Wireshark: I see the packages going through and answers coming back, thought the packets I see passing are far less than they are if I successfully connect to another HTTPS website. See the attached screenshot: I had to blur the IPs, anyway the longer string is my PC's local IP address, the shorter one is the customer's public IP. I don't know what else to try. This is the only IP doing this... Any idea what could I try to find a solution to this issue? Thanks, let me know if you need further details. Edit: when I say "it doesn't work" I mean: the page doesn't open, the browser keeps loading for a long time and eventually shows an error saying that the page cannot be opened. I'm not in my office now so I can't paste the exact message, but it's the usual message you get when the browser reaches its timeout. When I say "it works", I mean the browser loads and shows a webpage (it's the logon page for the customers' firewall admin interface: so there's the firewall brand's logo and there are fields to enter a user id and a password). Update 13/09/2012: tried again to connect to the customer's network through our Internet connection without a firewall. This is what I did: Run a Kubuntu 12.04 live distro on a spare laptop; Updated all the packages I could and installed WireShark; Attached it to my LAN and verified that I couldn't open https://<customer's IP>. Verified that the Wireshark trace for this attempt was the same as the one I've already posted; Verified that I could connect to another customer's host using rdesktop (it worked); Tried to rdesktop to <customer's IP>, here's the output: kubuntu@kubuntu:/etc$ rdesktop <customer's IP> Autoselected keyboard map en-us ERROR: recv: Connection reset by peer Disconnected the laptop from the LAN; Disconnected the firewall from the Extranet connection, connected the laptop instead. Set its network configuration so that I could access the Internet; Verified that I could connect to other websites in http and https and in RDP to other customers' hosts - it all worked as expected; Verified that I could still traceroute to <customer's IP>: I could; Verified that I still couldn't open https://<customer's IP> (same exact result as before); Checked the WireShark trace for this attempt and noticed a different behaviour: I could see packets going out to the customer's IP, but no replies at all; Tried to run rdesktop again, with a slightly different result: kubuntu@kubuntu:/etc/network$ rdesktop <customer's IP> Autoselected keyboard map en-us ERROR: <customer's IP>: unable to connect Finally gave up, put everything back as it was before, turned off the laptop and lost the WireShark traces I had saved. :( I still remember them very well though. :) Can you get anything out of it? Thank you very much. Update 12/09/2012 n.2: I followed the suggestion by MadHatter in the comments. From inside the firewall, this is what I get: user@ubuntu-mantis:~$ openssl s_client -connect <customer's IP>:443 CONNECTED(00000003) If I now type GET / the output pauses for several seconds and then I get: write:errno=104 I'm going to try the same, but bypassing the firewall, as soon as I can. Thanks. Update 12/09/2012 n.3: So, I think ISA Server is altering the results of my tests... I tried installing Wireshark directly on the firewall and monitoring the packets on the Extranet network card. When the destination is the customer's IP, whatever service I try to connect to (HTTPS, RDP or SAProuter), I can only see outbound packets and no response packets whatsoever from their side. It looks like ISA Server is "faking" the remote server's replies, that's why I get a connection using telnet or the openSSL client. This is the wireshark trace from inside our LAN: But this is the trace on the Extranet network card: This makes a bit more sense... I'll send this info to the customer's tech and see if he can make anything out of it. Thanks to all that took the time to read my question and post suggestions. I'll update this post again.

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  • Have suggestions for these assembly mnemonics?

    - by Noctis Skytower
    Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller halt End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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  • Making a non-trivial Image and Video Gallery with a really nice interface

    - by Cawas
    Short part: I'm starting to build an Image and Video Gallery for our intranet. It's pretty much like an image gallery with video thumbnails that play on click. It's just good to keep that in mind because caching and streaming happen in very different ways there. It will serve to browse our reference database, which will also contain searching, tagging and voting. There are 3 features that I need to begin with: Quick preview of thumbnails from each Gallery Fast zoom in / out Animated scrolling Now to the long part, since I can't seem to reduce this: I hope this question belongs here. Maybe people can read this through and identify with it, specially since I expect answers to be pretty specific. The first plan was getting Apple's mobile me gallery as base, because it just so happens to have all those 3 features. If you've never seem it, you should check it out. Move the mouse over each collection and you'll get a nice preview "per pixel". Carousel got a really good scrolling, not just because of the pretty effect. I like it much more than cooliris, but it would be nice to have it in several rows, maybe without the magnifying effect... Then it could be all in the same place with the zoom. The more the features blend-in together, the better. Zooming out with the mouse, scrolling by dragging, once the zoom is really out it becomes a browsing through galleries, with the quick-show preview of each, all properly cached and fast. That'd be perfect. A very compelling interface will be important in this project. Well, my point here is just describing what I need and hope to hear from people with more experience in all that stuff of what's already done and what I'd have to do myself. And how (i.e. which framework to use) to do it. To begin with, I've found a gallery demo and its source code (I think it was from here, but the link seems broken now). I guess it was made in SproutCore, which is what mobileme was based upon. Definitely with JQuery (which already seems a little slow). But I'm still missing two features there: the carousel and the fast zoom (it's just not as slow as the zoom in this demo with cappuccino). Then I've found a supposedly better one with a pretty good and similar zoom, that I'm not sure if it's using any framework and is already in php. Right now it'd be better having just the HTML, no server-side, since I'm building interface first. So, can anyone point directions? There are way too many options! Should I look for another solution closer to what I need, or try and tweak this one? I'm not familiar with any framework at all. Sorry for bringing this question that I will have to answer myself anyway sooner or later and sorry that I couldn't make this smaller. Thanks.

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  • Are their any suggestions for this new assembly language?

    - by Noctis Skytower
    Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller exit End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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  • Grails validation problems with sets of data: only getting one error message for all errors in a set

    - by Matt
    Hi, I'm trying to validate a domain class that has a number of subsets. class IebeUser { ... static hasMany = [openUserAnswers:OpenUserAnswer, closedUserAnswers:ClosedUserAnswer] } class OpenUserAnswer { OpenQuestion openQuestion String text static belongsTo = [user:IebeUser] static constraints = { openQuestion(nullable:false) text(blank:false) } } class ClosedUserAnswer { ClosedQuestion closedQuestion ClosedAnswer answer static belongsTo = [user:IebeUser] static constraints = { closedQuestion(nullable:false) answer(nullable:false) } } A closed question has a set of predefined answers and an open question lets the user enter a freeform answer. All is well until I come to validate the object after entry in a form: params: [closedUserAnswers[0].answer.id:, closedUserAnswers[0]:[answer:[id:], answer.id:], password:dfgdfgdf, openUserAnswers[0].text:gdfgdfgdfg, openUserAnswers[0]:[text:gdfgdfgdfg], _isOptedOut:, create:Continue, username:gdfgdfggdf, email:[email protected], closedUserAnswers[1].answer.id:, closedUserAnswers[1]:[answer:[id:], answer.id:], openUserAnswers[1].text:, openUserAnswers[1]:[text:], firstName:dfgdf, lastName:gdfgdfgd, action:save, controller:main] The key bits being: closedUserAnswers[0].answer.id:, closedUserAnswers[0]:[answer:[id:] closedUserAnswers[1].answer.id:, closedUserAnswers[1]:[answer:[id:] openUserAnswers[1].text:, openUserAnswers[1]:[text:] In my tests I have two objects of type closedUserAnswers and two of openUserAnswers. But when I call validation on IebeUser I only get validation errors for the closedUserAnswers or the openUserAnswers as a whole. I don't get validation errors for each object with a problem which is what I need. I really need an error per instance. Does anyone know what I'm doing wrong? Even when I call the validate method against each closedUserAnswer/openUserAnswer I still only get one per type. Here are my errors. Sorry for all the code, but thought I'd include as much of the code as possible so that it makes sense. Field error in object 'uk.co.cascaid.iebe.IebeUser' on field 'openUserAnswers.text': rejected value []; codes [uk.co.cascaid.iebe.OpenUserAnswer.text.blank.error.uk.co.cascaid.iebe.IebeUser.openUserAnswers.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.error.openUserAnswers.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.error.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.error,openUserAnswer.text.blank.error.uk.co.cascaid.iebe.IebeUser.openUserAnswers.text,openUserAnswer.text.blank.error.openUserAnswers.text,openUserAnswer.text.blank.error.text,openUserAnswer.text.blank.error,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.uk.co.cascaid.iebe.IebeUser.openUserAnswers.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.openUserAnswers.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank,openUserAnswer.text.blank.uk.co.cascaid.iebe.IebeUser.openUserAnswers.text,openUserAnswer.text.blank.openUserAnswers.text,openUserAnswer.text.blank.text,openUserAnswer.text.blank,blank.uk.co.cascaid.iebe.IebeUser.openUserAnswers.text,blank.openUserAnswers.text,blank.text,blank]; arguments [text,class uk.co.cascaid.iebe.OpenUserAnswer]; default message [Property [{0}] of class [{1}] cannot be blank] Field error in object 'uk.co.cascaid.iebe.IebeUser' on field 'closedUserAnswers.answer': rejected value [null]; codes [uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.error.uk.co.cascaid.iebe.IebeUser.closedUserAnswers.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.error.closedUserAnswers.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.error.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.error,closedUserAnswer.answer.nullable.error.uk.co.cascaid.iebe.IebeUser.closedUserAnswers.answer,closedUserAnswer.answer.nullable.error.closedUserAnswers.answer,closedUserAnswer.answer.nullable.error.answer,closedUserAnswer.answer.nullable.error,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.uk.co.cascaid.iebe.IebeUser.closedUserAnswers.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.closedUserAnswers.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable,closedUserAnswer.answer.nullable.uk.co.cascaid.iebe.IebeUser.closedUserAnswers.answer,closedUserAnswer.answer.nullable.closedUserAnswers.answer,closedUserAnswer.answer.nullable.answer,closedUserAnswer.answer.nullable,nullable.uk.co.cascaid.iebe.IebeUser.closedUserAnswers.answer,nullable.closedUserAnswers.answer,nullable.answer,nullable]; arguments [answer,class uk.co.cascaid.iebe.ClosedUserAnswer]; default message [Property [{0}] of class [{1}] cannot be null]

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  • Set up linux box for hosting a-z

    - by microchasm
    I am in the process of reinstalling the OS on a machine that will be used to host a couple of apps for our business. The apps will be local only; access from external clients will be via vpn only. The prior setup used a hosting control panel (Plesk) for most of the admin, and I was looking at using another similar piece of software for the reinstall - but I figured I should finally learn how it all works. I can do most of the things the software would do for me, but am unclear on the symbiosis of it all. This is all an attempt to further distance myself from the land of Configuration Programmer/Programmer, if at all possible. I can't find a full walkthrough anywhere for what I'm looking for, so I thought I'd put up this question, and if people can help me on the way I will edit this with the answers, and document my progress/pitfalls. Hopefully someday this will help someone down the line. The details: CentOS 5.5 x86_64 httpd: Apache/2.2.3 mysql: 5.0.77 (to be upgraded) php: 5.1 (to be upgraded) The requirements: SECURITY!! Secure file transfer Secure client access (SSL Certs and CA) Secure data storage Virtualhosts/multiple subdomains Local email would be nice, but not critical The Steps: Download latest CentOS DVD-iso (torrent worked great for me). Install CentOS: While going through the install, I checked the Server Components option thinking I was going to be using another Plesk-like admin. In hindsight, considering I've decided to try to go my own way, this probably wasn't the best idea. Basic config: Setup users, networking/ip address etc. Yum update/upgrade. Upgrade PHP/MySQL: To upgrade PHP and MySQL to the latest versions, I had to look to another repo outside CentOS. IUS looks great and I'm happy I found it! Add IUS repository to our package manager cd /tmp wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/epel-release-1-1.ius.el5.noarch.rpm rpm -Uvh epel-release-1-1.ius.el5.noarch.rpm wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/ius-release-1-4.ius.el5.noarch.rpm rpm -Uvh ius-release-1-4.ius.el5.noarch.rpm yum list | grep -w \.ius\. # list all the packages in the IUS repository; use this to find PHP/MySQL version and libraries you want to install Remove old version of PHP and install newer version from IUS rpm -qa | grep php # to list all of the installed php packages we want to remove yum shell # open an interactive yum shell remove php-common php-mysql php-cli #remove installed PHP components install php53 php53-mysql php53-cli php53-common #add packages you want transaction solve #important!! checks for dependencies transaction run #important!! does the actual installation of packages. [control+d] #exit yum shell php -v PHP 5.3.2 (cli) (built: Apr 6 2010 18:13:45) Upgrade MySQL from IUS repository /etc/init.d/mysqld stop rpm -qa | grep mysql # to see installed mysql packages yum shell remove mysql mysql-server #remove installed MySQL components install mysql51 mysql51-server mysql51-devel transaction solve #important!! checks for dependencies transaction run #important!! does the actual installation of packages. [control+d] #exit yum shell service mysqld start mysql -v Server version: 5.1.42-ius Distributed by The IUS Community Project Upgrade instructions courtesy of IUS wiki: http://wiki.iuscommunity.org/Doc/ClientUsageGuide Install rssh (restricted shell) to provide scp and sftp access, without allowing ssh login cd /tmp wget http://dag.wieers.com/rpm/packages/rssh/rssh-2.3.2-1.2.el5.rf.x86_64.rpm rpm -ivh rssh-2.3.2-1.2.el5.rf.x86_64.rpm useradd -m -d /home/dev -s /usr/bin/rssh dev passwd dev Edit /etc/rssh.conf to grant access to SFTP to rssh users. vi /etc/rssh.conf Uncomment or add: allowscp allowsftp This allows me to connect to the machine via SFTP protocol in Transmit (my FTP program of choice; I'm sure it's similar with other FTP apps). rssh instructions appropriated (with appreciation!) from http://www.cyberciti.biz/tips/linux-unix-restrict-shell-access-with-rssh.html Set up virtual interfaces ifconfig eth1:1 192.168.1.3 up #start up the virtual interface cd /etc/sysconfig/network-scripts/ cp ifcfg-eth1 ifcfg-eth1:1 #copy default script and match name to our virtual interface vi ifcfg-eth1:1 #modify eth1:1 script #ifcfg-eth1:1 | modify so it looks like this: DEVICE=eth1:1 IPADDR=192.168.1.3 NETMASK=255.255.255.0 NETWORK=192.168.1.0 ONBOOT=yes NAME=eth1:1 Add more Virtual interfaces as needed by repeating. Because of the ONBOOT=yes line in the ifcfg-eth1:1 file, this interface will be brought up when the system boots, or the network starts/restarts. service network restart Shutting down interface eth0: [ OK ] Shutting down interface eth1: [ OK ] Shutting down loopback interface: [ OK ] Bringing up loopback interface: [ OK ] Bringing up interface eth0: [ OK ] Bringing up interface eth1: [ OK ] ping 192.168.1.3 64 bytes from 192.168.1.3: icmp_seq=1 ttl=64 time=0.105 ms And this is where I'm at. I will keep editing this as I make progress. Any tips on how to Configure virtual interfaces/ip based virtual hosts for SSL, setting up a CA, or anything else would be appreciated.

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  • Are there any suggestions for these new assembly mnemonics?

    - by Noctis Skytower
    Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller halt End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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  • Bind: dns not 'spreaded'

    - by realtebo
    I've elfoip.net with bind $ whois elfoip.net | grep 'Name Server' Name Server: NS.ELFOIP.NET I need elfoip.net be able to serve third levels domain, like mickymouse.elfoip.net, etc... Yes, I'm trying to create an other useless dyndns clone. i've added some third level as A RR. Eg: executing this from the server itself $ dig @localhost mattinauno.elfoip.net ;; ANSWER SECTION: mattinauno.elfoip.net. 60 IN A 192.81.221.113 I was expecting in one or two days, from my pc i can digit in browser mattinauno.elfoip.net and get page a 192.81.221.113 But this is not happening. Are there any prerequisites to satisfy to allow dns of my isp to be able to forward dns resolution of *.elfoip.net to MY dns ? (Or to ask to him and then cache ?) TTL of zone is set a 5m I've not AllowQuey directive, is it necessary for other dns to cache from mine ? I've cheched the zone with bind utility named-checkzone but no error detected. How to diagnose why other dns doesn't take in account RR from mine ? from my home pc dig @ns.elfoip.net mattinauno.elfoip.net ;; ANSWER SECTION: mattinauno.elfoip.net. 60 IN A 192.81.221.113 ;; AUTHORITY SECTION: elfoip.net. 300 IN NS ns.elfoip.net. but dig @8.8.8.8 mattinauno.elfoip.net give no answers Whole zone file: note I've used nsupdate, so this file has been re-edited and re-formatted from this utility ! root@mirko:/var/named# cat elfoip.net.db $ORIGIN . $TTL 300 ; 5 minutes elfoip.net IN SOA ns.elfoip.net. hostmaster.elfoip.net. ( 2013062314 ; serial 3600 ; refresh (1 hour) 600 ; retry (10 minutes) 86400 ; expire (1 day) 60 ; minimum (1 minute) ) NS ns.elfoip.net. A 109.168.99.6 $ORIGIN elfoip.net. $TTL 60 ; 1 minute google A 173.194.35.56 maiscai A 192.81.221.113 mattinadue A 192.81.221.113 mattinauno A 192.81.221.113 $TTL 300 ; 5 minutes ns A 109.168.99.6 $TTL 60 ; 1 minute prova A 208.67.222.222 prova2 A 13.23.34.45 A 13.23.34.46 www CNAME elfoip.net. EDIT: added named.conf.local zone "elfoip.net" { type master; // file "/etc/bind/elfoip.net.db"; file "/var/named/elfoip.net.db"; allow-update { key elfoip.net ; }; }; EDIT: I've no setup list-on directive *EDIT Added a TCPDUMP after [email protected] wwww.elfoip.net from a machine which uses my company internal dns, who allow recursive query. root@mirko:~# tcpdump -i eth0 'port 53' tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes 11:57:23.293611 IP host9-210-static.22-87-b.business.telecomitalia.it.45958 > mirko.elfoip.net.domain: 61337+ A? www.elfoip.net. (32) 11:57:23.294114 IP mirko.elfoip.net.domain > host9-210-static.22-87-b.business.telecomitalia.it.45958: 61337* 2/1/1 CNAME elfoip.net., A 109.168.99.6 (95) 11:57:23.294554 IP mirko.elfoip.net.59571 > google-public-dns-a.google.com.domain: 45851+ PTR? 9.210.22.87.in-addr.arpa. (42) 11:57:23.330444 IP google-public-dns-a.google.com.domain > mirko.elfoip.net.59571: 45851 1/0/0 PTR host9-210-static.22-87-b.business.telecomitalia.it. (106) 11:57:23.331181 IP mirko.elfoip.net.44171 > google-public-dns-a.google.com.domain: 33339+ PTR? 8.8.8.8.in-addr.arpa. (38) 11:57:23.439405 IP google-public-dns-a.google.com.domain > mirko.elfoip.net.44171: 33339 1/0/0 PTR google-public-dns-a.google.com. (82) 11:57:31.350654 IP host9-210-static.22-87-b.business.telecomitalia.it.30108 > mirko.elfoip.net.domain: 38269 [1au] A? ns.elfoip.net. (42) 11:57:31.351117 IP mirko.elfoip.net.domain > host9-210-static.22-87-b.business.telecomitalia.it.30108: 38269* 1/1/1 A 109.168.99.6 (72) If i dig @8.8.8.8 www.elfoip.net, NOTHING happens in dump log !

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  • Cluster failover and strange gratuitous arp behavior

    - by lazerpld
    I am experiencing a strange Windows 2008R2 cluster related issue that is bothering me. I feel that I have come close as to what the issue is, but still don't fully understand what is happening. I have a two node exchange 2007 cluster running on two 2008R2 servers. The exchange cluster application works fine when running on the "primary" cluster node. The problem occurs when failing over the cluster ressource to the secondary node. When failing over the cluster to the "secondary" node, which for instance is on the same subnet as the "primary", the failover initially works ok and the cluster ressource continues to work for a couple of minutes on the new node. Which means that the recieving node does send out a gratuitous arp reply packet that updated the arp tables on the network. But after x amount of time (typically within 5 minutes time) something updates the arp-tables again because all of a sudden the cluster service does not answer to pings. So basically I start a ping to the exchange cluster address when its running on the "primary node". It works just great. I failover the cluster ressource group to the "secondary node" and I only have loss of one ping which is acceptable. The cluster ressource still answers for some time after being failed over and all of a sudden the ping starts timing out. This is telling me that the arp table initially is updated by the secondary node, but then something (which I haven't found out yet) wrongfully updates it again, probably with the primary node's MAC. Why does this happen - has anyone experienced the same problem? The cluster is NOT running NLB and the problem stops immidiately after failing over back to the primary node where there are no problems. Each node is using NIC teaming (intel) with ALB. Each node is on the same subnet and has gateway and so on entered correctly as far as I am concerned. Edit: I was wondering if it could be related to network binding order maybe? Because I have noticed that the only difference I can see from node to node is when showing the local arp table. On the "primary" node the arp table is generated on the cluster address as the source. While on the "secondary" its generated from the nodes own network card. Any input on this? Edit: Ok here is the connection layout. Cluster address: A.B.6.208/25 Exchange application address: A.B.6.212/25 Node A: 3 physical nics. Two teamed using intels teaming with the address A.B.6.210/25 called public The last one used for cluster traffic called private with 10.0.0.138/24 Node B: 3 physical nics. Two teamed using intels teaming with the address A.B.6.211/25 called public The last one used for cluster traffic called private with 10.0.0.139/24 Each node sits in a seperate datacenter connected together. End switches being cisco in DC1 and NEXUS 5000/2000 in DC2. Edit: I have been testing a little more. I have now created an empty application on the same cluster, and given it another ip address on the same subnet as the exchange application. After failing this empty application over, I see the exact same problem occuring. After one or two minutes clients on other subnets cannot ping the virtual ip of the application. But while clients on other subnets cannot, another server from another cluster on the same subnet has no trouble pinging. But if i then make another failover to the original state, then the situation is the opposite. So now clients on same subnet cannot, and on other they can. We have another cluster set up the same way and on the same subnet, with the same intel network cards, the same drivers and same teaming settings. Here we are not seeing this. So its somewhat confusing. Edit: OK done some more research. Removed the NIC teaming of the secondary node, since it didnt work anyway. After some standard problems following that, I finally managed to get it up and running again with the old NIC teaming settings on one single physical network card. Now I am not able to reproduce the problem described above. So it is somehow related to the teaming - maybe some kind of bug? Edit: Did some more failing over without being able to make it fail. So removing the NIC team looks like it was a workaround. Now I tried to reestablish the intel NIC teaming with ALB (as it was before) and i still cannot make it fail. This is annoying due to the fact that now i actually cannot pinpoint the root of the problem. Now it just seems to be some kind of MS/intel hick-up - which is hard to accept because what if the problem reoccurs in 14 days? There is a strange thing that happened though. After recreating the NIC team I was not able to rename the team to "PUBLIC" which the old team was called. So something has not been cleaned up in windows - although the server HAS been restarted! Edit: OK after restablishing the ALB teaming the error came back. So I am now going to do some thorough testing and i will get back with my observations. One thing is for sure. It is related to Intel 82575EB NICS, ALB and Gratuitous Arp.

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  • asp.net listbox

    - by lodun
    Why this code don't work,when i want run this code vwd 2008 express show me this error: Object reference not set to an instance of an object. Line 73: kom.Parameters.Add("@subcategories", SqlDbType.Text).Value = s_categoreis.SelectedItem.ToString(); This is my ascx file: <asp:ListBox ID="categories" runat="server" Height="380px" CssClass="kat" AutoPostBack="true" DataSourceID="SqlDataSource1" DataTextField="Categories" DataValueField="ID" onselectedindexchanged="kategorije_SelectedIndexChanged"></asp:ListBox> <asp:Button ID="Button1" CssClass="my" runat="server" Text="click" onclick="Button1_Click" /> <asp:UpdatePanel ID="UpdatePanel1" runat="server"> <ContentTemplate> <asp:ListBox ID="s_categoreis" CssClass="pod" Height="150px" Enabled="true" runat="server"></asp:ListBox></ContentTemplate> <Triggers> <asp:AsyncPostBackTrigger ControlID="categories" EventName="SelectedIndexChanged" /> </Triggers> </asp:UpdatePanel> <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:estudent_piooConnectionString %>" SelectCommand="SELECT [ID], [Categories] FROM [categories]"> </asp:SqlDataSource> and this is my ascx.cs: SqlConnection veza; SqlCommand kom = new SqlCommand(); SqlParameter par1 = new SqlParameter(); SqlParameter par2 = new SqlParameter(); SqlParameter par3 = new SqlParameter(); SqlParameter par4 = new SqlParameter(); SqlParameter par5 = new SqlParameter(); SqlParameter par6 = new SqlParameter(); SqlParameter par7 = new SqlParameter(); SqlParameter par8 = new SqlParameter(); SqlParameter par9 = new SqlParameter(); protected void Page_Load(object sender, EventArgs e) { Listapod_kategorije(1); } protected void kategorije_SelectedIndexChanged(object sender, EventArgs e) { Listapod_kategorije(Convert.ToInt32(kategorije.SelectedValue)); } private void Listapod_kategorije(int broj) { SqlDataSource ds = new SqlDataSource(); ds.ConnectionString = ConfigurationManager.ConnectionStrings["estudent_piooConnectionString"].ConnectionString; ds.SelectCommand = "Select * from pod_kategorije where kat_id=" + broj; pod_kategorije.DataSource = ds; pod_kategorije.DataTextField = "pkategorija"; pod_kategorije.DataValueField = "ID"; pod_kategorije.DataBind(); } protected void Button1_Click(object sender, EventArgs e) { Guid jk = new Guid(); object datum = DateTime.Now; veza = new SqlConnection(@"server=85.94.76.170\PADME; database=estudent_pioo;uid=pioo;pwd=1234567"); Random broj = new Random(); int b_kor = broj.Next(1, 1000); kom.Parameters.Add("@text", SqlDbType.Text).Value = str; kom.Parameters.Add("@user", SqlDbType.UniqueIdentifier).Value = jk; kom.Parameters.Add("@date", SqlDbType.DateTime).Value = datum; kom.Parameters.Add("@visits", SqlDbType.Int).Value = 0; kom.Parameters.Add("@answers", SqlDbType.Int).Value = 0; kom.Parameters.Add("@username", SqlDbType.Text).Value = "unknown_" + b_kor.ToString(); ; kom.Parameters.Add("@categories", SqlDbType.Text).Value = categories.SelectedItem.ToString(); kom.Parameters.Add("@sub_categories", SqlDbType.Text).Value = s_categoreis.SelectedItem.ToString(); veza.Open(); kom.ExecuteNonQuery(); veza.Close(); Response.Redirect("default.aspx");

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  • Evidence-Based-Scheduling - are estimations only as accurate as the work-plan they're based on?

    - by Assaf Lavie
    I've been using FogBugz's Evidence Based Scheduling (for the uninitiated, Joel explains) for a while now and there's an inherent problem I can't seem to work around. The system is good at telling me the probability that a given project will be delivered at some date, given the detailed list of tasks that comprise the project. However, it does not take into account the fact that during development additional tasks always pop up. Now, there's the garbage-can approach of creating a generic task/scheduled-item for "last minute hacks" or "integration tasks", or what have you, but that clearly goes against the idea of aggregating the estimates of many small cases. It's often the case that during the development stage of a project you realize that there's a whole area your planning didn't cover, because, well, that's the nature of developing stuff that hasn't been developed before. So now your ~3 month project may very well turn into a 6 month project, but not because your estimations were off (you could be the best estimator in the world, for those task the comprised your initial work plan); rather because you ended up adding a whole bunch of new tasks that weren't there to begin with. EBS doesn't help you with that. It could, theoretically (I guess). It could, perhaps, measure the amount of work you add to a project over time and take that into consideration when estimating the time remaining on a given project. Just a thought. In other words, EBS works on a task basis, but not on a project/release basis - but the latter is what's important. It's what your boss typically cares about - delivery date, not the time it takes to finish each task along the way, and not the time it would have taken, if your planning was perfect. So the question is (yes, there's a question here, don't close it): What's your methodology when it comes to using EBS in FogBugz and how do you solve the problem above, which seems to be a main cause of schedule delays and mispredictions? Edit Some more thoughts after reading a few answers: If it comes down to having to choose which delivery date you're comfortable presenting to your higher-ups by squinting at the delivery-probability graph and choosing 80%, or 95%, or 60% (based on what, exactly?) then we've resorted to plain old buffering/factoring of our estimates. In which case, couldn't we have skipped the meticulous case by case hour-sized estimation effort step? By forcing ourselves to break down tasks that take more than a day into smaller chunks of work haven't we just deluded ourselves into thinking our planning is as tight and thorough as it could be? People may be consistently bad estimators that do not even learn from their past mistakes. In that respect, having an EBS system is certainly better than not having one. But what can we do about the fact that we're not that good in planning as well? I'm not sure it's a problem that can be solved by a similar system. Our estimates are wrong because of tendencies to be overly optimistic/pessimistic about certain tasks, and because of neglect to account for systematic delays (e.g. sick days, major bug crisis) - and usually not because we lack knowledge about the work that needs to be done. Our planning, on the other hand, is often incomplete because we simply don't have enough knowledge in this early stage; and I don't see how an EBS-like system could fill that gap. So we're back to methodology. We need to find a way to accommodate bad or incomplete work plans that's better than voodoo-multiplication.

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  • which control in vs08 aspx c# will be able to take html tags as input and display it formatted accor

    - by user287745
    i asked a few questions regarding this and got answers that indicate i will have to make an costum build editor using ,markdown, .... to achieve something like stackoverflow.com/questions/ask page. there is time limitation and the requirements are that much, i have to achieve 1) allow users to using html tags when giving input 2) save that complete input to sql db 3) display the data in db withing a contol which renders the formatting as the tags specify. i am aware label and literal controls support html tags, the problem is how to allow the user to input the textbox does not seem the support html tags? thank you Need help in implementing the affect of the WRITE A NEW POST On stackoverflow.com <%--The editor--% <asp:UpdatePanel ID="UpdatePanel7" runat="server"> <ContentTemplate> <asp:Label ID="Label4" runat="server" Text="Label"></asp:Label> <div id="textchanging" onkeyup="textoftextbox('TextBox3'); return false;"> <asp:TextBox ID="TextBox3" runat="server" CausesValidation="True" ></asp:TextBox> </div> <%-- OnTextChanged="textoftextbox('TextBox3'); return false;" gives too man literals error. --%> <asp:Button ID="Button6" runat="server" Text="Post The Comment, The New, Write on Wall" onclick="Button6_Click" /> <asp:Label ID="Label2" runat="server" Text="Label"></asp:Label> <asp:TextBox ID="TextBox4" runat="server" CausesValidation="True"></asp:TextBox> <asp:Literal ID="Literal2" runat="server" Text="this must change" here comes the div <div id="displayingarea" runat="server">This area will change</div> </ContentTemplate> </asp:UpdatePanel> <%--The editor ends--%> protected void Button6_Click(object sender, EventArgs e) { Label3.Text = displayingarea.InnerHtml; } As you see, I have implemented the effect of typing text in textbox which appears as a reflection in the div WITH FULLY FORMATTED TEXT ACCORDIG TO THE HTML TAGS USED The textbox does not allow html! Well the text box doesnot have too, script just extracts what is typed, within letting the server know. The html of the div tag also changes as typed in textbox. Now, There is a “post” button within an update plane a avoid full post back of page What I needis when the button is clicked on the value withing the div tag “innerhtml” is passed on to the label. Yes I know the chnages are only made on the client side, So when the button click event occurs the server is not aware of the new data within the div tag, Therefore the server assign the original html withing the div to the lab. Need help to overcome this, How is it that what we enter text in the textbox press the button with coding like label1.text=textbox1.text; and it works even in update panel, but the aabove code for extracting innerhtml typed at users end similar to yping in textbox does not work?

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  • Facebook, Yimg and google-analytics CDNs is freaking me out

    - by Millisami
    Hi, Its been a couple of weeks that some sites just keeps on hanging. e.g. Facebooks = static.ak.fbcdn.net FLicker = l.yimg.com GoogleAnalytics I've googled and found many problems like this and some answers which are outdated or just doesn't solve the problem. I did: Cookies clearing, ran cc cleaner and several other nifty methods. None solved my problem?? Only with facebook, if I enter https:// manually instead of http:// on every url on facebook, it works and when it does the redirection to http://, everytime I have to type 's' on the address bar to make it https:// It is driving me nuts coz I'm developing Facebook App and this problem in being pain in my ass. What might be the reason for these CDNs hanging behaviour?? Update: Mon Feb 8, 2010 Well when I viewed the source with firefox, this is the header part: <link type="text/css" rel="stylesheet" href="http://b.static.ak.fbcdn.net/rsrc.php/zDO0B/hash/8jpbog60.css" /> <link type="text/css" rel="stylesheet" href="http://static.ak.fbcdn.net/rsrc.php/zA96O/hash/8jqnsh63.css" /> <link type="text/css" rel="stylesheet" href="http://b.static.ak.fbcdn.net/rsrc.php/z9X8U/hash/5zy5e7ns.css" /> <link type="text/css" rel="stylesheet" href="http://b.static.ak.fbcdn.net/rsrc.php/z7XWB/hash/b881ctjq.css" /> <link type="text/css" rel="stylesheet" href="http://static.ak.fbcdn.net/rsrc.php/zEMLE/hash/6n3druoq.css" /> <link type="text/css" rel="stylesheet" href="http://b.static.ak.fbcdn.net/rsrc.php/zEEQQ/hash/3et16vbl.css" /> <link type="text/css" rel="stylesheet" href="http://b.static.ak.fbcdn.net/rsrc.php/zF0BN/hash/4ey03a8b.css" /> #<link type="text/css" rel="stylesheet" href="http://b.static.ak.fbcdn.net/rsrc.php/zD46U/hash/4ctxkmr7.css" /> <script type="text/javascript" src="http://b.static.ak.fbcdn.net/rsrc.php/z5KPU/hash/f92tjc5l.js"></script> When I clicked the each link, all links open with its contents except the last link with -# sign prefixed. So the url -#http://b.static.ak.fbcdn.net/rsrc.php/zD46U/hash/4ctxkmr7.css is not opening and this css file is not downloaded and the facebook page looks horrible and all left aligned?? Update: Tue Feb 9, 2010 Today the link with the -# sign is just keeps hanging and looping: <link type="text/css" rel="stylesheet" href="http://static.ak.fbcdn.net/rsrc.php/zEMLE/hash/6n3druoq.css" /> <link type="text/css" rel="stylesheet" href="http://b.static.ak.fbcdn.net/rsrc.php/z9X8U/hash/5zy5e7ns.css" /> <link type="text/css" rel="stylesheet" href="http://b.static.ak.fbcdn.net/rsrc.php/zF0BN/hash/4ey03a8b.css" /> <link type="text/css" rel="stylesheet" href="http://static.ak.fbcdn.net/rsrc.php/z1580/hash/4l5utauj.css" /> #<link type="text/css" rel="stylesheet" href="http://b.static.ak.fbcdn.net/rsrc.php/z4851/hash/532htj7z.css" /> <link type="text/css" rel="stylesheet" href="http://static.ak.fbcdn.net/rsrc.php/z1GEW/hash/dh01t0zv.css" /> <link type="text/css" rel="stylesheet" href="http://static.ak.fbcdn.net/rsrc.php/z80UK/hash/3a6o59ih.css" /> <link type="text/css" rel="stylesheet" href="http://b.static.ak.fbcdn.net/rsrc.php/zD46U/hash/4ctxkmr7.css" /> <script type="text/javascript" src="http://b.static.ak.fbcdn.net/rsrc.php/z5KPU/hash/f92tjc5l.js"></script> Why that url http://b.static.ak.fbcdn.net acting weird? Has something Akamai got to do with this?

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  • Design Question - how do you break the dependency between classes using an interface?

    - by Seth Spearman
    Hello, I apologize in advance but this will be a long question. I'm stuck. I am trying to learn unit testing, C#, and design patterns - all at once. (Maybe that's my problem.) As such I am reading the Art of Unit Testing (Osherove), and Clean Code (Martin), and Head First Design Patterns (O'Reilly). I am just now beginning to understand delegates and events (which you would see if you were to troll my SO questions of recent). I still don't quite get lambdas. To contextualize all of this I have given myself a learning project I am calling goAlarms. I have an Alarm class with members you'd expect (NextAlarmTime, Name, AlarmGroup, Event Trigger etc.) I wanted the "Timer" of the alarm to be extensible so I created an IAlarmScheduler interface as follows... public interface AlarmScheduler { Dictionary<string,Alarm> AlarmList { get; } void Startup(); void Shutdown(); void AddTrigger(string triggerName, string groupName, Alarm alarm); void RemoveTrigger(string triggerName); void PauseTrigger(string triggerName); void ResumeTrigger(string triggerName); void PauseTriggerGroup(string groupName); void ResumeTriggerGroup(string groupName); void SetSnoozeTrigger(string triggerName, int duration); void SetNextOccurrence (string triggerName, DateTime nextOccurrence); } This IAlarmScheduler interface define a component that will RAISE an alarm (Trigger) which will bubble up to my Alarm class and raise the Trigger Event of the alarm itself. It is essentially the "Timer" component. I have found that the Quartz.net component is perfectly suited for this so I have created a QuartzAlarmScheduler class which implements IAlarmScheduler. All that is fine. My problem is that the Alarm class is abstract and I want to create a lot of different KINDS of alarm. For example, I already have a Heartbeat alarm (triggered every (int) interval of minutes), AppointmentAlarm (triggered on set date and time), Daily Alarm (triggered every day at X) and perhaps others. And Quartz.NET is perfectly suited to handle this. My problem is a design problem. I want to be able to instantiate an alarm of any kind without my Alarm class (or any derived classes) knowing anything about Quartz. The problem is that Quartz has awesome factories that return just the right setup for the Triggers that will be needed by my Alarm classes. So, for example, I can get a Quartz trigger by using TriggerUtils.MakeMinutelyTrigger to create a trigger for the heartbeat alarm described above. Or TriggerUtils.MakeDailyTrigger for the daily alarm. I guess I could sum it up this way. Indirectly or directly I want my alarm classes to be able to consume the TriggerUtils.Make* classes without knowing anything about them. I know that is a contradiction, but that is why I am asking the question. I thought about putting a delegate field into the alarm which would be assigned one of these Make method but by doing that I am creating a hard dependency between alarm and Quartz which I want to avoid for both unit testing purposes and design purposes. I thought of using a switch for the type in QuartzAlarmScheduler per here but I know it is bad design and I am trying to learn good design. If I may editorialize a bit. I've decided that coding (predefined) classes is easy. Design is HARD...in fact, really hard and I am really fighting feeling stupid right now. I guess I want to know if you really smart people took a while to really understand and master this stuff or should I feel stupid (as I do) because I haven't grasped it better in the couple of weeks/months I have been studying. You guys are awesome and thanks in advance for your answers. Seth

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  • How do I properly add existing source code files to my Xcode project?

    - by BeachRunnerJoe
    I'm new to iPhone development and I'm still getting familiar with the Mac dev environment, including Xcode. I want to add some 3rd party code to my iPhone project, but when I add the "existing files" to my Xcode project, I'm presented with a dialog box that has far too many options that I don't understand and, as such, my project isn't working. When I #import headerfilename.h, I get a build error that reads headerfilename.h: No such file or directory. Can anyone explain to me what all these options mean or give me a link to some documentation that can? I'm having a hard time finding anything in Apple's docs. Which options do I want to choose to add existing source code files to my Xcode project? I should note that the source code files that I'm trying to add are located in my project/Classes/frameworkname/ directory. After they're added, do I need to reference this new code directory in my project settings anywhere (i.e. some kind of header file directory variable)? Thanks so much! Update: I found the following answers/responses on the apple dev forums that were very useful and helped me fix my issue... To make it simple : - if you do not check the copy option, the file stay where it is. - if you check it, it is copied in your project folders In the first case (what it seems you are doing) you need to tell the compiler that the header files are in another directory : - project info - build - search paths - User Header Search Path : add the directory from where you took the header file Hope this will help You have discovered the most confusing dialog box that ever came out of Cupertino. Six years of Xcode, and this thing still is partly a mystery to me. To even get that far, I had to make many test projects to try and reverse-engineer what this thing does. The "Copy" box means that it will copy the files as they are right now, into the project. If this box is not checked, then it just references those files during a build and copies them as they are at THAT time. For source code, you want the Copy box checked. The "relative to" is a total mystery to me and I can't help you with that. I usually leave it however it is already set. Does it mean relative to where they are on disk, or the arrangement in Xcode, or in the bundle? Who knows. The last 2 radio buttons SEEM to mean that it will either re-create the folder structure of the folder you are adding, or just put "fake" folders in Xcode that point to the real folders. This is probably your problem - you are adding source code that is not all at the top level, and when it goes to find it, it does not re-create the hierarchy. Others can supply a better way, hopefully, but what I would do is put all of the source in one folder and add that, using the Copy box. Then in Xcode you can make whatever bogus folders you want and put the source file names in those fake folders.

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  • Covariance and Contravariance in C#

    - by edalorzo
    I will start by saying that I am Java developer learning to program in C#. As such I do comparisons of what I know with what I am learning. I have been playing with C# generics for a few hours now, and I have been able to reproduce the same things I know in Java in C#, with the exception of a couple of examples using covariance and contravariance. The book I am reading is not very good in the subject. I will certainly seek more info on the web, but while I do that, perhaps you can help me find a C# implementation for the following Java code. An example is worth a thousand words, and I was hoping that by looking a good code sample I will be able to assimilate this more rapidly. Covariance In Java I can do something like this: public static double sum(List<? extends Number> numbers) { double summation = 0.0; for(Number number : numbers){ summation += number.doubleValue(); } return summation; } I can use this code as follows: List<Integer> myInts = asList(1,2,3,4,5); List<Double> myDoubles = asList(3.14, 5.5, 78.9); List<Long> myLongs = asList(1L, 2L, 3L); double result = 0.0; result = sum(myInts); result = sum(myDoubles) result = sum(myLongs); Now I did discover that C# supports covariance/contravariance only on interfaces and as long as they have been explicitly declared to do so (out). I think I was not able to reproduce this case, because I could not find a common ancestor of all numbers, but I believe that I could have used IEnumerable to implement such thing if a common ancestor exists. Since IEnumerable is a covariant type. Right? Any thoughts on how to implement the list above? Just point me into the right direction. Is there any common ancestor of all numeric types? Contravariance The contravariance example I tried was the following. In Java I can do this to copy one list into another. public static void copy(List<? extends Number> source, List<? super Number> destiny){ for(Number number : source) { destiny.add(number); } } Then I could use it with contravariant types as follows: List<Object> anything = new ArrayList<Object>(); List<Integer> myInts = asList(1,2,3,4,5); copy(myInts, anything); My basic problem, trying to implement this in C# is that I could not find an interface that was both covariant and contravariant at the same time, as it is case of List in my example above. Maybe it can be done with two different interface in C#. Any thoughts on how to implement this? Thank you very much to everyone for any answers you can contribute. I am pretty sure I will learn a lot from any example you can provide.

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  • [C#] Not enough memory or not enough handles?

    - by Nayan
    I am working on a large scale project where a custom (pretty good and robust) framework has been provided and we have to use that for showing up forms and views. There is abstract class StrategyEditor (derived from some class in framework) which is instantiated whenever a new StrategyForm is opened. StrategyForm (a customized window frame) contains StrategyEditor. StrategyEditor contains StrategyTab. StrategyTab contains StrategyCanvas. This is a small portion of the big classes to clarify that there are many objects that will be created if one StrategyForm object is allocated in memory at run-time. My component owns all these classes mentioned above except StrategyForm whose code is not in my control. Now, at run-time, user opens up many strategy objects (which trigger creation of new StrategyForm object.) After creating approx. 44 strategy objects, we see that the USER OBJECT HANDLES (I'll use UOH from here onwards) created by the application reaches to about 20k+, while in registry the default amount for handles is 10k. Read more about User Objects here. Testing on different machines made it clear that the number of strategy objects opened is different for message to pop-up - on one m/c if it is 44, then it can be 40 on another. When we see the message pop-up, it means that the application is going to respond slowly. It gets worse with few more objects and then creation of window frames and subsequent objects fail. We first thought that it was not-enough-memory issue. But then reading more about new in C# helped in understanding that an exception would be thrown if app ran out of memory. This is not a memory issue then, I feel (task manager also showed 1.5GB+ available memory.) M/C specs Core 2 Duo 2GHz+ 4GB RAM 80GB+ free disk space for page file Virtual Memory set: 4000 - 6000 My questions Q1. Does this look like a memory issue and I am wrong that it is not? Q2. Does this point to exhaustion of free UOHs (as I'm thinking) and which is resulting in failure of creation of window handles? Q3. How can we avoid loading up of an StrategyEditor object (beyond a threshold, keeping an eye on the current usage of UOHs)? (we already know how to fetch number of UOHs in use, so don't go there.) Keep in mind that the call to new StrategyForm() is outside the control of my component. Q4. I am bit confused - what are Handles to user objects exactly? Is MSDN talking about any object that we create or only some specific objects like window handles, cursor handles, icon handles? Q5. What exactly cause to use up a UOH? (almost same as Q4) I would be really thankful to anyone who can give me some knowledgeable answers. Thanks much! :)

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  • Implementing a robust async stream reader for a console

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. Edit: There are comments below correctly stating that since the data is coming from a stream, there is absolutely nothing that the receiver can infer about the structure of the data unless it is fully prepared to parse it. What I am trying to do here is leverage the "flush the output" "structure" that the owner of the console imparts while writing on it. I am prepared to assume (better: allow my caller to have the option to assume) that the OS will pass me the data written between two flushes of the stream in exactly one piece. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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  • com.sun.org.apache.xerces.internal.dom.DocumentImpl cannot be cast to org.codehaus.plexus.util.xml.X

    - by Random
    Afetr using the Model library (see this) for my Maven pom.xml during this weeks I jumped on this error while attempting to write a ConfiguratonContainer into the pom.xml. The javadoc for Model says: public void setConfiguration(Object configuration) Set the configuration as DOM object. Parameters: configuration - So I made some xml with Document (org.w3c.dom.Document) and the xml parser standar javax library. You know the code (it's through all the net) but I paste it here... DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder parser = factory.newDocumentBuilder(); Document doc =parser.newDocument(); And then you fill the code with Element declaration,a lot of appendChild and such. And tried to make it work. Doesn't seem to do well. First tried using plugin.setConfiguration(doc); But it didn't work. Then I tried Obejct obj = doc; plugin.setConfiguration(obj); But it didn't work. Then I searched the net for answers, and guess... It didn't work. There are like 0 people using this library (maven.model) in all the net. So here am I again, asking the senseis for help. Where is my error? I have downloaded the source code of the library trying to see where is the error, but it seems to be ok (as should). I add the stackrace for reference java.lang.ClassCastException: com.sun.org.apache.xerces.internal.dom.DocumentImpl cannot be cast to org.codehaus.plexus.util.xml.Xpp3Dom at org.apache.maven.model.io.xpp3.MavenXpp3Writer.writePlugin(MavenXpp3Writer.java:1472) at org.apache.maven.model.io.xpp3.MavenXpp3Writer.writeBuild(MavenXpp3Writer.java:326) at org.apache.maven.model.io.xpp3.MavenXpp3Writer.writeModel(MavenXpp3Writer.java:1093) at org.apache.maven.model.io.xpp3.MavenXpp3Writer.write(MavenXpp3Writer.java:102) at com.mapfre.mutua.PDA.model.GeneratePOM.createPOM(GeneratePOM.java:28) at com.mapfre.mutua.PDA.prueba.MavenPOM.generatePOMWAR(MavenPOM.java:681) at com.mapfre.mutua.PDA.prueba.GenerarPOMMapfreAction.execute(GenerarPOMMapfreAction.java:36) at org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58) at org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67) at org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51) at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191) at org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:305) at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191) at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913) at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462) at javax.servlet.http.HttpServlet.service(HttpServlet.java:647) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:873) at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665) at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528) at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689) at java.lang.Thread.run(Unknown Source)

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