Search Results

Search found 44956 results on 1799 pages for 'type checking'.

Page 552/1799 | < Previous Page | 548 549 550 551 552 553 554 555 556 557 558 559  | Next Page >

  • How do I make the gtk code work?

    - by Runner
    vbox = gtk_vbox_new(FALSE, 0); gtk_container_add(GTK_CONTAINER(window), vbox); ... frame = gtk_fixed_new(); gtk_container_add(GTK_CONTAINER(window), frame); ... The above code will generate the warning below: Gtk-WARNING **: Attempting to add a widget with type GtkFixed to a GtkWindow, but as a GtkBin subclass a GtkWindow can only contain one widget at a time; it already contains a widget of type GtkVBox Which results in frame is not shown in the window. How can I make both vbox and frame show?

    Read the article

  • Having to hit the site login button twice after first turning on computer

    - by John
    Hello, The code below is for a login that I'm using. It works fine, but when I first try logging in after turning on my computer, it only works the second time that I hit the "Login" button. Any idea how I can make it not require hitting the "Login" button twice in this situation? Thanks in advance, John function isLoggedIn() { if (session_is_registered('loginid') && session_is_registered('username')) { return true; // the user is loged in } else { return false; // not logged in } return false; } if (!isLoggedIn()) { if (isset($_POST['cmdlogin'])) { if (checkLogin($_POST['username'], $_POST['password'])) { show_userbox(); } else { echo "Incorrect Login information !"; show_loginform(); } } else { show_loginform(); } } else { show_userbox(); } function show_loginform($disabled = false) { echo '<form name="login-form" id="login-form" method="post" action="./index.php"> <div class="usernameformtext"><label title="Username">Username: </label></div> <div class="usernameformfield"><input tabindex="1" accesskey="u" name="username" type="text" maxlength="30" id="username" /></div> <div class="passwordformtext"><label title="Password">Password: </label></div> <div class="passwordformfield"><input tabindex="2" accesskey="p" name="password" type="password" maxlength="15" id="password" /></div> <div class="registertext"><a href="http://www...com/sandbox/register.php" title="Register">Register</a></div> <div class="lostpasswordtext"><a href="http://www...com/sandbox/lostpassword.php" title="Lost Password">Lost password?</a></div> <p class="loginbutton"><input tabindex="3" accesskey="l" type="submit" name="cmdlogin" value="Login" '; if ($disabled == true) { echo 'disabled="disabled"'; } echo ' /></p></form>'; } EDIT: Here is another function that is used. function isLoggedIn() { if (session_is_registered('loginid') && session_is_registered('username')) { return true; // the user is loged in } else { return false; // not logged in } return false; }

    Read the article

  • Broadcast receiver, check status, turning off connection with F8

    - by yoann
    I am using eclipse with android sdk 3.2 I have some problems to make my broadcast receiver working when the connection is lost. first I have checked the type of network to make sure I understand well : ConnectivityManager manager = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE); boolean is3g = manager.getNetworkInfo( ConnectivityManager.TYPE_MOBILE) .isConnectedOrConnecting(); boolean isWifi = manager.getNetworkInfo( ConnectivityManager.TYPE_WIFI) .isConnectedOrConnecting(); NetworkInfo info = manager.getActiveNetworkInfo(); if (info != null) Toast.makeText(getApplicationContext(), info.getTypeName(), Toast.LENGTH_LONG).show(); else Toast.makeText(getApplicationContext(), "Pas de connexion", Toast.LENGTH_LONG).show(); if (!is3g) Log.i("Network Listener", "DISCONNECTED"); else Log.i("Network Listener", "CONNECTED"); == this is a mobile network, I'm connected Then I press F8 or I make : telnet localhost 5554 gsm data off to stop the connection Here is my dynamic broadcast receiver in an activity : public class ActivityA extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.query); this.registerReceiver(this.networkStateReceiver, new IntentFilter( ConnectivityManager.CONNECTIVITY_ACTION)); } BroadcastReceiver networkStateReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { ConnectivityManager connMgr = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo networkInfo = connMgr.getActiveNetworkInfo(); //i have tried several things : State networkState = networkInfo.getState(); // if (networkState.compareTo(State.DISCONNECTED) == 0) ... if (networkInfo != null && networkInfo.isConnected()) { Toast.makeText(getApplicationContext(), "CONNECTED", Toast.LENGTH_LONG).show(); Log.i("Network Listener", "Connected"); } else { Toast.makeText(getApplicationContext(), "DISCONNECTED", Toast.LENGTH_LONG).show(); Log.i("Network Listener", "Network Type Changed"); Intent offline = new Intent(AccountInfoActivity.this, OfflineWorkService.class); startService(offline); } }; My manifest : <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> The problem is : when the activityA is launched, my broadcast receive something and it displays "Connected"(Log) and my toast. When I turn off the connection manually, nothing happend. My service is not started, log message are not displayed, only toast messages work ... And even better, when I turn on the connection again (by pressing F8), I test again the type of connection, Toast messages are shown but this time Log messages don't work. Problems happend when I press F8. Anyway, I think I miss something with broadcast receivers, it's not totally clear. Please help me.

    Read the article

  • How can I fix this configure error?

    - by balor123
    I'm trying to build mosh from source on a SUSE10 machine and am getting the following error: checking for protobuf... no configure: error: Package requirements (protobuf) were not met: No package 'protobuf' found Consider adjusting the PKG_CONFIG_PATH environment variable if you installed software in a non-standard prefix. Alternatively, you may set the environment variables protobuf_CFLAGS and protobuf_LIBS to avoid the need to call pkg-config. See the pkg-config man page for more details. I downloaded the source to protobuf and installed it in a custom path as well. I'm not using a package manager for any of this and cannot for various reasons outside the scope of the question. I added that custom path to my PATH and rehashed. Typically, this is enough for configure but in this case its not doing the trick. I added the prefix for protobuf to PKG_CONFIG_PATH but am still hitting this error. What should I do next to get past this error?

    Read the article

  • Rails Unit Testing with MyISAM Tables

    - by tadman
    I've got an application that requires the use of MyISAM on a few tables, but the rest are the traditional InnoDB type. The application itself is not concerned with transactions where it applies to these records, but performance is a concern. The Rails testing environment assumes the engine used is transactional, though, so when the test database is generated from the schema.rb it is imported with the same engine. Is it possible to over-ride this behaviour in a simple manner? I've resorted to an awful hack to ensure the tables are the correct type by appending this to test_helper.rb: (ActiveRecord::Base.connection.select_values("SHOW TABLES") - %w[ schema_info ]).each do |table_name| ActiveRecord::Base.connection.execute("ALTER TABLE `#{table_name}` ENGINE=InnoDB") end Is there a better way to make a MyISAM-backed model be testable?

    Read the article

  • Problem upgrading kernel on debian 3.1

    - by exhuma
    Hi, I have a quite old box in a remote server farm. So I have no direct access. Only remote SSH (and via SSH to a serial console). I haven't updated this box in ages. Now, whenever I want to install a new package, a dependency to glibc appears. Unfortunately, the install of glibc depends on a 2.6 kernel and I am running a venerable 2.4 kernel (one more reason to upgrade). The problem is, that the install of a new kernel has an indirect (over locales) dependency to glibc. So, to install glibc, I need a new kernel. For a new kernel, I need to upgrade glibc. Essentially I am blocked. What's the best way to proceed considering I have no "hardware" access? Here's a quick transcript of the upgrade process: [green:~]% sudo aptitude install linux-image-686 Reading Package Lists... Done Building Dependency Tree Reading extended state information Initializing package states... Done Reading task descriptions... Done The following packages are unused and will be REMOVED: gcc-4.3-base The following NEW packages will be automatically installed: dash libc6-i686 libparse-recdescent-perl linux-image-2.6-686 linux-image-2.6.18-6-686 module-init-tools yaird The following packages have been kept back: adduser apache2 apache2-mpm-prefork apache2-utils apache2.2-common apt apt-utils aptitude autoconf autotools-dev awstats base-files base-passwd [...snip...] util-linux vacation vim vim-common wamerican wbritish wget whiptail whois wwwconfig-common zlib1g The following NEW packages will be installed: dash libc6-i686 libparse-recdescent-perl linux-image-2.6-686 linux-image-2.6.18-6-686 linux-image-686 module-init-tools yaird The following packages will be upgraded: hotplug libc6 2 packages upgraded, 8 newly installed, 1 to remove and 277 not upgraded. Need to get 0B/22.7MB of archives. After unpacking 52.1MB will be used. Do you want to continue? [Y/n/?] Writing extended state information... Done Preconfiguring packages ... (Reading database ... 34065 files and directories currently installed.) Preparing to replace libc6 2.3.6.ds1-13 (using .../libc6_2.7-18lenny2_i386.deb) ... Checking for services that may need to be restarted... Checking init scripts... WARNING: init script for postgresql not found. [ --- libc6 config screen appears here --- ] WARNING: POSIX threads library NPTL requires kernel version 2.6.8 or later. If you use a kernel 2.4, please upgrade it before installing glibc. The installation of a 2.6 kernel _could_ ask you to install a new libc first, this is NOT a bug, and should *NOT* be reported. In that case, please add etch sources to your /etc/apt/sources.list and run: apt-get install -t etch linux-image-2.6 Then reboot into this new kernel, and proceed with your upgrade dpkg: error processing /var/cache/apt/archives/libc6_2.7-18lenny2_i386.deb (--unpack): subprocess pre-installation script returned error exit status 1 Errors were encountered while processing: /var/cache/apt/archives/libc6_2.7-18lenny2_i386.deb E: Sub-process /usr/bin/dpkg returned an error code (1) Ack! Something bad happened while installing packages. Trying to recover: dpkg: dependency problems prevent configuration of locales: locales depends on glibc-2.7-1; however: Package glibc-2.7-1 is not installed. dpkg: error processing locales (--configure): dependency problems - leaving unconfigured Errors were encountered while processing: locales Reading Package Lists... Done Building Dependency Tree Reading extended state information Initializing package states... Done Reading task descriptions... Done Now, if I follow the instrunctions as promted I get the following. Note that I am using aptitude instead of apt-get to benefit from the better dependency tracking. I did try with apt-get first. But that let me to the same problem. [green:~]% sudo aptitude install -t etch linux-image-2.6.26-2-686 Reading Package Lists... Done Building Dependency Tree Reading extended state information Initializing package states... Done Reading task descriptions... Done E: Unable to correct problems, you have held broken packages. E: Unable to correct dependencies, some packages cannot be installed E: Unable to resolve some dependencies! Some packages had unmet dependencies. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following packages have unmet dependencies: linux-image-2.6.26-2-686: Depends: initramfs-tools (>= 0.55) but it is not installable or yaird (>= 0.0.13) but it is not installable or linux-initramfs-tool which is a virtual package. Any ideas?

    Read the article

  • Polymorphic functions with parameters from a class hierarchy

    - by myahya
    Let's say I have the following class hierarchy in C++: class Base; class Derived1 : public Base; class Derived2 : public Base; class ParamType; class DerivedParamType1 : public ParamType; class DerivedParamType2 : public ParamType; And I want a polymorphic function, func(ParamType), defined in Base to take a parameter of type DerivedParamType1 for Derived1 and a parameter of type DerivedParamType2 for Derived2. How would this be done without pointers, if possible?

    Read the article

  • Javascript & Jquery why it doesnt work on IE?

    - by Yetkin EREN
    i cant run any function on ie this is a little part; my test page : http://www.yetkineren.com/testpage.html code: <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" /> <title>test page</title> </head> <body> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.1/jquery.min.js"> </script> <script type="text/javascript" language="javascript"> function kutuyap(Eid,iduzan,yazi,yer,ekle){ var div; div = document.createElement('div') div.id = Eid+iduzan; document.getElementById(yer).appendChild(div); //$('#'+yer).append("<div id="+Eid+iduzan+"></div>") $('#'+Eid+iduzan).addClass("minikutu"); $('#'+Eid+iduzan).html(" "+yazi+'<span id='+Eid+'y'+iduzan+' class="yokedici">X</span>'); // $("#"+Eid+'y'+iduzan).attr("onclick","kutusil('"+Eid+"y"+iduzan+"','"+iduzan+"','"+ekle+"');"); $("#"+Eid+'y'+iduzan).click(function() { kutusil(Eid+'y'+iduzan, iduzan, ekle); }); $('#'+ekle).val($('#'+ekle).val()+Eid+'-'); } function kutusil(Eid,iduzan,ekle){ $('#'+Eid).live('click',function() { sil=$(this).parents("div:first").attr("id"); silinecek=sil.replace(iduzan,''); $('#'+ekle).val($('#'+ekle).val().replace(silinecek+'-','')); $(this).parents("div:first").remove(); }); } </script> <select name="Mturs" class="inputs" id="Mturs"> <option value="0" selected="selected">Choise One</option> <option value="4">Pop</option> <option value="3">Pop-Rock </option> <option value="5">Rock (Yabanci)</option> </select> <input name="secMtur" id="secMtur" value="" type="hidden"> <script> $('#Mturs').live('change', function() { $('#Mturs :selected').each(function (i) { if ( $('#Mturs :selected').val() != 0 ) { secMturde=$('#secMtur').val().indexOf($('#Mturs :selected').val()+'-'); splitter=$('#secMtur').val().split("-") if(splitter.length<=12){ if (secMturde<0) { kutuyap($('#Mturs :selected').val(),'mtur',$(this).html(),'divmtur','secMtur'); }else{ alert("Choisen before") } }else{ alert("Max limit is 12 !") } } }); }); </script>

    Read the article

  • How do I find hash value of a 3D vector ?

    - by brainydexter
    I am trying to perform broad-phase collision detection with a fixed-grid size approach. Thus, for each entity's position: (x,y,z) (each of type float), I need to find which cell does the entity lie in. I then intend to store all the cells in a hash-table and then iterate through to report (if any) collisions. So, here is what I am doing: Grid-cell's position: (int type) (Gx, Gy, Gz) = (x / M, y / M, z / M) where M is the size of the grid. Once, I have a cell, I'd like to add it to a hash-table with its key being a unique hash based on (Gx, Gy, Gz) and the value being the cell itself. Now, I cannot think of a good hash function and I need some help with that. Can someone please suggest me a good hash function? Thanks

    Read the article

  • dd clone hard drive: Input/Output Error though "chkdsk" says OK

    - by unknown (google)
    Hi, I've used dd to clone hard drives before using 'dd' and a live cd, but have run into a problem. The issue: dd fails with an "Input/Output Error" on /dev/sda3 , even though windows "check disk" (chkdsk) says it's ok. Context: Trying to replace my laptop hard drive w/ a faster one of the same size Laptop has NTFS on a 320gb hard drive Booting into knoppix Knoppix recognizes 'original' drive (/dev/sda) I am using a usb connection for ‘new' drive (irrelevant, but just an fyi) Knoppix recognizes the usb drive as /dev/sdb Using dd, as follows: dd if=/dev/sda of=/dev/sdb "dd" gives the I/O error above at 82Gb (out of 320Gb) I then tried checking each partition as follows and found it failed on /dev/sda3: dd if=/dev/sda1 of=/dev/null dd if=/dev/sda2 of=/dev/null dd if=/dev/sda3 of=/dev/null I have ran windows xp chkdsk on the offending drive in both "find only" and "find and fix" mode and it reports no errors Question How can I find and fix the error on my original hard drive partition (i.e. /dev/sda3) so that dd reads it successfully?

    Read the article

  • Why does a checkbox's "checked" attribute return the opposite of it's actual value on click event?

    - by Kappers
    I've got the following HTML <li><input type="checkbox" /><label>This is the label!</label></li> I bound a click event to the li, and let the click event bubble up to the li before doing anything else. $('li').each(function(i){ var item = $(this); var checkbox = $("input[type='checkbox']", item); item.bind('click', function(e){ var isChecked = checkbox.is(':checked'); console.log(isChecked); e.stopPropagation(); }); }); Starting with an unchecked checkbox, when the click event fires, isChecked returns true when I click on the checkbox, but returns false when I click on the label or li. Does anyone know why?

    Read the article

  • Play wave file using AudioFormat in java

    - by angelina
    Dear all, I m getting following exception while running my code on linux operating system.This code works fine on windows operating system.below is the exception and code used. java.lang.IllegalArgumentException: No line matching interface Clip supporting format PCM_SIGNED unknown sample rate, 16 bit, stereo, 4 bytes/frame, big-endian is supported. AudioFormat format = sourceaudio.getFormat(); format = new AudioFormat( AudioFormat.Encoding.PCM_SIGNED, format.getSampleRate(), format.getSampleSizeInBits() * 2, format.getChannels(), format.getFrameSize() * 2, format.getFrameRate(), true); AudioFileFormat.Type targettype = AudioFileFormat.Type.WAVE; AudioInputStream targetaudiostream = AudioSystem.getAudioInputStream(format, sourceaudio); sourceaudio.close(); targetaudiostream.close(); System.out.println("55555555"); URL url = new URL("http://localhost:8084/newvideo/PCMfile.wav"); Clip clip = AudioSystem.getClip(); AudioInputStream ais = AudioSystem.getAudioInputStream(url); clip.open(ais); System.out.println("seconds: " + (clip.getMicrosecondLength() / 1000000));

    Read the article

  • How do you update a TextField from a grails remoteLink?

    - by Randyaa
    Existing markup: <g:textField name="identifier"/> <g:remoteLink action="newId" update="identifier">generate new id</g:remoteLink> Corresponding HTML markup: <input type="text" id="identifier" name="identifier"> <a onclick="new Ajax.Updater('guid','/webapp/domain/newId',{asynchronous:true,evalScripts:true});return false;" href="/webapp/domain/newId">generate</a> The HTML markup it generates when the link is clicked: <input type="text" id="identifier" name="identifier">THE-NEW-ID-HERE</input> <a onclick="new Ajax.Updater('guid','/webapp/domain/newId',{asynchronous:true,evalScripts:true});return false;" href="/webapp/domain/newId">generate</a>

    Read the article

  • Inconsistent DNS report results on different websites

    - by Saif Bechan
    I am checking my server dns setting on different websites. intodns,dnssy,dnscog, but on all the websites i get different results. Some say my mail server settings are not good, some say i have no A records for my NS records. Only on dnssy everything looks to be ok. Should i just trust the website with the best results, or what should i do? How does this sort of inconsistency occur in the first place. I am new to servers and dns, and this makes it very misleading.

    Read the article

  • LIKE query for DateTime in NHibernate

    - by Anry
    For a column of type varchar I could write such a query: public IList<Order> GetByName(string orderName) { using (ISession session = NHibernateHelper.OpenSession()) { return session.CreateCriteria<Order>(). Add(Restrictions.Like("Name", string.Format("%{0}%", orderName))). List<Order>(); } } How do I write a similar LIKE-query for a column that has type datetime? public IList<Order> GetByDateTime(DateTime dateTime) { using (ISession session = NHibernateHelper.OpenSession()) { return //LIKE-query } } That is, if the method is passed the date and part-time (eg "25.03.2010 19"), then displays all orders are carried out in this period of time.

    Read the article

  • Python code formatting

    - by Curious2learn
    In response to another question of mine, someone suggested that I avoid long lines in the code and to use PEP-8 rules when writing Python code. One of the PEP-8 rules suggested avoiding lines which are longer than 80 characters. I changed a lot of my code to comply with this requirement without any problems. However, changing the following line in the manner shown below breaks the code. Any ideas why? Does it have to do with the fact that what follows return command has to be in a single line? The line longer that 80 characters: def __str__(self): return "Car Type \n"+"mpg: %.1f \n" % self.mpg + "hp: %.2f \n" %(self.hp) + "pc: %i \n" %self.pc + "unit cost: $%.2f \n" %(self.cost) + "price: $%.2f "%(self.price) The line changed by using Enter key and Spaces as necessary: def __str__(self): return "Car Type \n"+"mpg: %.1f \n" % self.mpg + "hp: %.2f \n" %(self.hp) + "pc: %i \n" %self.pc + "unit cost: $%.2f \n" %(self.cost) + "price: $%.2f "%(self.price)

    Read the article

  • Which development Language is best suited to Network Inventory

    - by dastardlyandmuttley
    Dear stackoverflow I hope this is the corrcet type of question for stackoverflow to consider I would like to develop a "Hard Core" application that performs Network Inventory. High level requirements are Work on Windows and UNIX networks it has to be extremly performant it has to be 100% accuarate (massively) scalable and fun to write The sort of details I am after is manufacturer and versions of all major workstation hardware components such as motherboard, network card, sound card, hard drives, optical drives, memory, BIOS details, operating system information etc. I dont want to have to distribute a client on each workstation to collect the information although i will require automatic worksattion discovery I would value your thoughts on the best development language to employ I know there are products such as NEWT and stuff like nmap... I would like to do this type of technical programming myself "from scratch" Warm Regards DD

    Read the article

  • asp.net mvc json open dialog box problem

    - by mazhar kaunain baig
    function postForm() { $.ajax({ type: "POST", data: $("#myForm").serialize(), dataType: "json", url: '<%= Url.Action("JSONRequest","Home") %>', success: function(result) { window.alert(result.name); }, error : function() { window.alert('error'); } }); } Html.BeginForm("JSONRequest", "Home", FormMethod.Post, new { id = "myForm" }); Html.TextBox("mazhar") <input type="submit" onclick="postForm" /> Html.EndForm(); public ActionResult JSONRequest(FormCollection form) { string a = form["mazhar"]; var data = new { name = "aaaa", Success = "Record is Succesfully Saved", ErrorMessages = "abc" }; return Json(data); } Ok the problem is that the dialog box is opening after running this code which is asking to save file. Can someone tell me how to resolve this issue?

    Read the article

  • Choosing the right .NET architecture. WCF? WPF/Forms, ASP.NET (MVC)?

    - by Tommy Jakobsen
    I’m in the situation that I have to design and implement a rather big system from the bottom. I’m having some (a lot actually) questions about the architecture that I would like your comments and thoughts on. I don’t hope that I’ve written too much here, but I wanted to give you all an idea of what the system is. Quick info about the applications, read if you want: I can’t share much detail about the project, but basically it’s a system where we offer our customer a service to manage their users. We have a hotline where the users call and our hotline uses an (windows) application (intranet) to manage the user’s data, etc. The customer also has a web application where they can see reports, information about their business and users, and the ability to modify their data. Modifying data is not just user data like address and so, but also information about the products/services the user has, which can be complicated. The applications will be built on Microsoft .NET Framework 4, with a MS SQL Server 2008 database. There will be a few applications that have to access this database, such as: Intranet application (used by us and our hotline) Customer web application type 1 Customer web application type 2 Customer web application type n different applications) … Now my big problem is what .NET parts I should use for such a system. For the “backend” I’ve considered using Windows Communication Foundation: Would WCF be a good choice? The intranet application will be an application that has to edit lots of records in the database. It has to be easy to navigate using the keyboard (fast to work with). Has a feature such as “find customer, find that, lookup this, choose this and update that”. What would be the best choice to develop this application in? Would it be WPF or good old Windows Forms? I don’t need all of the fancy graphics features in WPF, like 3D, but the application has to look nice (maybe something like the new Visual Studio/Office tools). And the same question goes for the web pages. They have much the same work to do, but not as many features as the intranet application, and not the same amount of data (much less). That is my questions for now. I’m hoping to get a discussion going that will open my eyes to some of these technologies, helping me decide architecture to go with. I would like to say thanks in advance, and let you all know that any thoughts will be much appreciated.

    Read the article

  • ADO.NET Entity Framework: Can I have multiple entity types for the same row.

    - by black_nm
    Hi all, I have a base class Participants inherited by Artist, Author and TextWriter. I have only one table in the data store: Participants { ID, FirstName, LastName, IsArtist, IsAuthor, IsTextWriter, } The idea is to have a class for all the roles that a participant can have. I've managed to create the edmx file but when I try to get an Participant (as Artist) that is also an Author I receive the following error: All objects in the EntitySet 'Participants' must have unique primary keys. However, an instance of type 'Artist' and an instance of type 'Author' both have the same primary key value, 'EntitySet=Participants;ID=1'. Thank you

    Read the article

  • Watching a variable for changes without polling.

    - by milkfilk
    I'm using a framework called Processing which is basically a Java applet. It has the ability to do key events because Applet can. You can also roll your own callbacks of sorts into the parent. I'm not doing that right now and maybe that's the solution. For now, I'm looking for a more POJO solution. So I wrote some examples to illustrate my question. Please ignore using key events on the command line (console). Certainly this would be a very clean solution but it's not possible on the command line and my actual app isn't a command line app. In fact, a key event would be a good solution for me but I'm trying to understand events and polling beyond just keyboard specific problems. Both these examples flip a boolean. When the boolean flips, I want to fire something once. I could wrap the boolean in an Object so if the Object changes, I could fire an event too. I just don't want to poll with an if() statement unnecessarily. import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; /* * Example of checking a variable for changes. * Uses dumb if() and polls continuously. */ public class NotAvoidingPolling { public static void main(String[] args) { boolean typedA = false; String input = ""; System.out.println("Type 'a' please."); while (true) { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); try { input = br.readLine(); } catch (IOException ioException) { System.out.println("IO Error."); System.exit(1); } // contrived state change logic if (input.equals("a")) { typedA = true; } else { typedA = false; } // problem: this is polling. if (typedA) System.out.println("Typed 'a'."); } } } Running this outputs: Type 'a' please. a Typed 'a'. On some forums people suggested using an Observer. And although this decouples the event handler from class being observed, I still have an if() on a forever loop. import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.Observable; import java.util.Observer; /* * Example of checking a variable for changes. * This uses an observer to decouple the handler feedback * out of the main() but still is polling. */ public class ObserverStillPolling { boolean typedA = false; public static void main(String[] args) { // this ObserverStillPolling o = new ObserverStillPolling(); final MyEvent myEvent = new MyEvent(o); final MyHandler myHandler = new MyHandler(); myEvent.addObserver(myHandler); // subscribe // watch for event forever Thread thread = new Thread(myEvent); thread.start(); System.out.println("Type 'a' please."); String input = ""; while (true) { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); try { input = br.readLine(); } catch (IOException ioException) { System.out.println("IO Error."); System.exit(1); } // contrived state change logic // but it's decoupled now because there's no handler here. if (input.equals("a")) { o.typedA = true; } } } } class MyEvent extends Observable implements Runnable { // boolean typedA; ObserverStillPolling o; public MyEvent(ObserverStillPolling o) { this.o = o; } public void run() { // watch the main forever while (true) { // event fire if (this.o.typedA) { setChanged(); // in reality, you'd pass something more useful notifyObservers("You just typed 'a'."); // reset this.o.typedA = false; } } } } class MyHandler implements Observer { public void update(Observable obj, Object arg) { // handle event if (arg instanceof String) { System.out.println("We received:" + (String) arg); } } } Running this outputs: Type 'a' please. a We received:You just typed 'a'. I'd be ok if the if() was a NOOP on the CPU. But it's really comparing every pass. I see real CPU load. This is as bad as polling. I can maybe throttle it back with a sleep or compare the elapsed time since last update but this is not event driven. It's just less polling. So how can I do this smarter? How can I watch a POJO for changes without polling? In C# there seems to be something interesting called properties. I'm not a C# guy so maybe this isn't as magical as I think. private void SendPropertyChanging(string property) { if (this.PropertyChanging != null) { this.PropertyChanging(this, new PropertyChangingEventArgs(property)); } }

    Read the article

  • WinForms: Why do I get InvalidCastException when showing folder browser dialog?

    - by Marek
    I am randomly getting InvalidCastException when showing FolderBrowserDialog and also many clients have reported this. I have not been able to find anything relevant on the internet. Does anyone know what causes this/how to fix this? My code: using (FolderBrowserDialog fbd = new FolderBrowserDialog()) { fbd.ShowNewFolderButton = false; if (fbd.ShowDialog() == DialogResult.OK) Stack trace: Error: System.InvalidCastException: 'Unable to cast object of type 'System.__ComObject' to type 'IMalloc'.'. Stack trace: at System.Windows.Forms.UnsafeNativeMethods.Shell32.SHGetMalloc(IMalloc[] ppMalloc) at System.Windows.Forms.FolderBrowserDialog.GetSHMalloc() at System.Windows.Forms.FolderBrowserDialog.RunDialog(IntPtr hWndOwner) at System.Windows.Forms.CommonDialog.ShowDialog(IWin32Window owner) at System.Windows.Forms.CommonDialog.ShowDialog() EDIT: Additional information: I have been able to reproduce this only when running in VS2008 debugger. When running out of debugger, it happens only very rarely (happened once or twice in 6 months) on my 64 bit Windows 7 and goes away after restart. The clients are certainly not running the app in debugger so it is surely reproducible out of debugger.

    Read the article

  • Spawn phone call from EC2 alerts

    - by Matt
    I have a system setup on AWS/EC2, it currently is using their CloudWatch alert system. The problem is this sends just to email, when ideally I would like this to be making a phone call and/or sending text messages to certain phone numbers when an alert fires (Note that I do not need the phone call to actually say anything, just call the person). We are trying to solve the problem that Amazon alerts are only useful if people are checking their email, which isnt always the case because all server problems love to happen at 4am on saturday... Please respond with any possible solutions/ideas, ideally I do not want to implement an entire monitoring system (IE: Nagios) on top of everything to handle this.

    Read the article

  • load a pickle file from a zipfile

    - by eric.frederich
    For some reason I cannot get cPickle.load to work on the file-type object returned by ZipFile.open(). If I call read() on the file-type object returned by ZipFile.open() I can use cPickle.loads though. Example .... import zipfile import cPickle # the data we want to store some_data = {1: 'one', 2: 'two', 3: 'three'} # # create a zipped pickle file # zf = zipfile.ZipFile('zipped_pickle.zip', 'w', zipfile.ZIP_DEFLATED) zf.writestr('data.pkl', cPickle.dumps(some_data)) zf.close() # # cPickle.loads works # zf = zipfile.ZipFile('zipped_pickle.zip', 'r') sd1 = cPickle.loads(zf.open('data.pkl').read()) zf.close() # # cPickle.load doesn't work # zf = zipfile.ZipFile('zipped_pickle.zip', 'r') sd2 = cPickle.load(zf.open('data.pkl')) zf.close() Note: I don't want to zip just the pickle file but many files of other types. This is just an example.

    Read the article

  • How to make multiple queries with PHP prepared statements (Commands out of sync error)

    - by Tirithen
    I'm trying to run three MySQL queries from a PHP script, the first one works fine, but on the second one I get the "Commands out of sync; you can’t run this command now" error. I have managed to understand that I need to "empty" the resultset before preparing a new query but I can't seem to understand how. I thought that $statement-close; would do that for me. Here is the relevant part of the code: <?php $statement = $db_conn->prepare("CALL getSketches(?,?)"); // Prepare SQL routine to check if user is accepted $statement->bind_param("is", $user_id, $loaded_sketches); // Bind variables to send $statement->execute(); // Execute the query $statement->bind_result( // Set return varables $id, $name, $description, $visibility, $createdby_id, $createdby_name, $createdon, $permission ); $new_sketches_id = array(); while($statement->fetch()) { $result['newSketches'][$id] = array( "name" => $name, "description" => $description, "visibility" => $visibility, "createdById" => $createdby_id, "createdByName" => $createdby_name, "createdOn" => $createdon, "permission" => $permission ); $new_sketches_id[] = $id; } $statement->close; // Close satement $new_sketches_ids = implode(",", $new_sketches_id); // Get the new sketches elements $statement = $db_conn->prepare("CALL getElements(?,'',?,'00000000000000')"); // Prepare SQL routine to check if user is accepted // The script crashes here with $db_conn->error // "Commands out of sync; you can't run this command now" $statement->bind_param("si", $new_sketches_ids, $user_id); // Bind variables to send $statement->execute(); // Execute the query $statement->bind_result( // Set return varables $id, $user_id, $type, $attribute_d, $attribute_stroke, $attribute_strokeWidth, $sketch_id, $createdon ); while($statement->fetch()) { $result['newSketches'][$sketch_id]['newElements']["u".$user_id."e".$id] = array( "type" => $type, "d" => $attribute_d, "stroke" => $attribute_stroke, "strokeWidth" => $attribute_strokeWidth, ); } $statement->close; // Close satement ?> How can I make the second query without closing and reopening the entire database connection?

    Read the article

< Previous Page | 548 549 550 551 552 553 554 555 556 557 558 559  | Next Page >