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  • c# counting identical strings from text file

    - by Winkz
    I have a foreach statement where I go through several lines from a text file, where I have trimmed down and sorted out the lines I need. What I want to do is count up on how many times an identical string is present. How do I do this? Here is my code. It's the second if statement where I am stuck: foreach (string line in lines.Where(l => l.Length >= 5)) { string a = line.Remove(0, 11); if ((a.Contains(mobName) && a.Contains("dies"))) { mobDeathCount++; } if (a.Contains(mobName) && a.Contains("drops")) { string lastpart = a.Substring(a.LastIndexOf("drops")); string modifiedLastpart = lastpart.Remove(0, 6); } Heres what some of the lines look like: a bag of coins a siog brandy a bag of coins a bag of coins the Cath Shield a tattered scroll So what im trying to do is counting up there are 3 lines with bag of coins. But i need to make it so that it can be everything, theres a drop lists thats huge. So cant add all of em, would take too long

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  • Destroy? Delete? What's going on here? Rails 2.3.5

    - by Steve
    I am new to rails. My rails version is 2.3.5. I found usage like: In controller, a destroy method is defined and in view, you can use :action = "delete" to fire that method. Isn't the action name has to be the same as the method name? Why delete is mapped to destroy? Again, in my controller, I define a method called destroy to delete a record. In a view, I have <%= link_to "remove", :action = 'destroy', :id = myrecord %. But it never works in practice. Every time I press the remove link, it redirects me to the show view, showing the record's content. I am pretty sure that my destroy method is: def destroy @myobject = MyObject.find(params[:id]) @myobject.destroy @redirect_to :action = 'index' end If I change the method name from destroy to something like remove_me and change the action name to remove_me in the view, everything works as expected. In the above two wired problems, I am sure there is no tricky rountting set in my configuration. All in all, seems the destroy and delete are mysterious keywords in rails. Anyone can explain this to me? Thank you very much.

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  • How To Delete objet whit mouse click ?

    - by Meko
    Hi all. I made a simple FlowChat Editor that creates rectangles and triangles and connect them each other and shows the way from up to down. I can move this elements on screen to .But I am tying to create button to delete element which I clicked. There is problem that I can delete mytriangle object but but I cant delete myRectangle objects.It deletes but not object which i clicked.I delete from first object to last ..Here my code ... if (deleteObj) { if (rectsList.size() != 0) { for (int i = 0; i < rectsList.size(); i++) { MyRect rect = (MyRect) rectsList.get(i); if (e.getX() <= rect.c.x + 50 && e.getX() >= rect.c.x - 50 && e.getY() <= rect.c.y + 15 && e.getY() >= rect.c.y - 15) { rectsList.remove(rect); System.out.println("This is REctangle DELETED\n"); } } } if (triangleList.size() != 0) { for (int j = 0; j < triangleList.size(); j++) { MyTriangle trian = (MyTriangle) triangleList.get(j); if (e.getX() <= trian.c.x + 20 && e.getX() >= trian.c.x - 20 && e.getY() <= trian.c.y + 20 && e.getY() >= trian.c.y - 20) { triangleList.remove(trian); System.out.println("This is Triangle Deleted\n"); } } }

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  • Javascript for disabling dropdown in ASP.NET

    - by Lijo
    Hi Team, I am using JScript in ASP.NET 2005. I have a page with a checkbox and a dropdown list. When the checkbox is checked the dropdown is to be disabled. During Postback of the page this should be retained. I am using a javascript function as follows if((chkOwner[1].checked==true)) { document.getElementById(ddlClientID).disabled=true; document.getElementById(ddlClientID).className = "form-disabled"; document.getElementById(ddlClientID).selectedIndex = 0; } else { document.getElementById(ddlClientID).disabled=false; document.getElementById(ddlClientID).className = "form-input"; document.getElementById(ddlClientID).selectedIndex = 0; } This works, almost. However, the dropdown selection is not retained after postback (when checkbox is not selected). Apprently the solution is to remove the last line, i.e, in the else part, remove the selectedIndex =0 setting. But, when I do that the disabling of dropdown (when check box is selected) is not working after post back. Could you please help on this? Thanks Lijo

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  • .NET List Thread-Safe Implementation Suggestion needed

    - by Bamboo
    .Net List class isn't thread safe. I hope to achieve the minimal lock needed and yet still fulfilling the requirement such that as for reading, phantom record is allowed, and for writing, they must be thread-safe so there won't be any lost updates. So I have something like public static List<string> list = new List<string>(); In Methods that have **List.Add**/**List.Remove** , I always lock to assure thread safety lock (lockHelper) { list.Add(obj); or list.Remove(obj); } In Methods that requires **List Reading** I don't care about phantom record so I go ahead to read without any locking. In this case. Return a bool by checking whether a string had been added. if (list.Count() != 0) { return list.Contains("some string") } All I did was locking write accesses, and allow read accesses to go through without any locking. Is my thread safety idea valid? I understand there is List size expansion. Will it be ok? My guess is that when a List is expanding, it may uses a temp. list. This is ok becasue the temp list size will always have a boundary, and .Net class is well implemented, ie. there shouldn't be any indexOutOfBound or circular reference problems when reading was caught in updates.

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  • Java: Efficient Equivalent to Removing while Iterating a Collection

    - by Claudiu
    Hello everyone. We all know you can't do this: for (Object i : l) if (condition(i)) l.remove(i); ConcurrentModificationException etc... this apparently works sometimes, but not always. Here's some specific code: public static void main(String[] args) { Collection<Integer> l = new ArrayList<Integer>(); for (int i=0; i < 10; ++i) { l.add(new Integer(4)); l.add(new Integer(5)); l.add(new Integer(6)); } for (Integer i : l) { if (i.intValue() == 5) l.remove(i); } System.out.println(l); } This, of course, results in: Exception in thread "main" java.util.ConcurrentModificationException ...even though multiple threads aren't doing it... Anyway. What's the best solution to this problem? "Best" here means most time and space efficient (I realize you can't always have both!) I'm also using an arbitrary Collection here, not necessarily an ArrayList, so you can't rely on get.

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  • jQuery removeClass(), how it works

    - by centro
    I have images on my page. User can add more images onto the page by clicking a button. New images are added asynchronously. Initially, each image on page use a special class to be used when the image is loaded. After the image is loaded, that class is removed. Each image being loaded has the class imageLoading: <img class="imageLoading" scr="someimage.png"> After those images are loaded, I remove that class (simplified code without details): $('img.imageLoading') .each(function(){ $(this) .load(function(){ $(this) .removeClass('imageloading'); });}); Visually, I see that style is removed. But when I run the query again: $('img.imageLoading') I see via debugging that all images, not just loading ones, are returned, i.e. it works like I didn't remove the class for the images that were already loaded. I had a look into the page source, and I saw that actually in HTML the class was not removed, though removeClass() was called. Is that behavior by design that all visual changes are applied but the class attribute is not removed in HTML code? If so, how it can be workarounded in this case. Or, probably, I missed something.

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  • Adding images to an array memory issue

    - by Friendlydeveloper
    Hello all, I'm currently facing the following issue: My app dynamically creates images (320 x 480 pixels) and adds them to a NSMutableArray. I need those images inside that array in order to allow users to browse through them back and forth. I only need to keep the latest 5 images. So I wrote a method like below: - (void)addImageToArray:(UIImage*)theImage { if ([myMutableArray count] < 5) { [myMutableArray addObject:theImage]; } else { [myMutableArray removeObjectAtIndex:0]; [myMutableArray addObject:theImage]; } } This method basically does what it's supposed to do. However, in instruments I can see, that memory usage is permanently incrementing. At some point, even though I do not have any memory leaks, the app finally crashes. The way I see it, XCode does remove the image from my array, but does not release it. Is there a way I can make sure, that the object I want to remove from my array will also get released? Maybe my approach is completely wrong and I need to find a different way. Any help appreciated. Thanks in advance

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  • method works fine, until it is called in a function, then UnboundLocalError

    - by user1776100
    I define a method called dist, to calculate the distance between two points which I does it correctly when directly using the method. However, when I get a function to call it to calculate the distance between two points, I get UnboundLocalError: local variable 'minkowski_distance' referenced before assignment edit sorry, I just realised, this function does work. However I have another method calling it that doesn't. I put the last method at the bottom This is the method: class MinkowskiDistance(Distance): def __init__(self, dist_funct_name_str = 'Minkowski distance', p=2): self.p = p def dist(self, obj_a, obj_b): distance_to_power_p=0 p=self.p for i in range(len(obj_a)): distance_to_power_p += abs((obj_a[i]-obj_b[i]))**(p) minkowski_distance = (distance_to_power_p)**(1/p) return minkowski_distance and this is the function: (it basically splits the tuples x and y into their number and string components and calculates the distance between the numeric part of x and y and then the distance between the string parts, then adds them. def total_dist(x, y, p=2, q=2): jacard = QGramDistance(q=q) minkowski = MinkowskiDistance(p=p) x_num = [] x_str = [] y_num = [] y_str = [] #I am spliting each vector into its numerical parts and its string parts so that the distances #of each part can be found, then summed together. for i in range(len(x)): if type(x[i]) == float or type(x[i]) == int: x_num.append(x[i]) y_num.append(y[i]) else: x_str.append(x[i]) y_str.append(y[i]) num_dist = minkowski.dist(x_num,y_num) str_dist = I find using some more steps #I am simply adding the two types of distance to get the total distance: return num_dist + str_dist class NearestNeighbourClustering(Clustering): def __init__(self, data_file, clust_algo_name_str='', strip_header = "no", remove = -1): self.data_file= data_file self.header_strip = strip_header self.remove_column = remove def run_clustering(self, max_dist, p=2, q=2): K = {} #dictionary of clusters data_points = self.read_data_file() K[0]=[data_points[0]] k=0 #I added the first point in the data to the 0th cluster #k = number of clusters minus 1 n = len(data_points) for i in range(1,n): data_point_in_a_cluster = "no" for c in range(k+1): distances_from_i = [total_dist(data_points[i],K[c][j], p=p, q=q) for j in range(len(K[c]))] d = min(distances_from_i) if d <= max_dist: K[c].append(data_points[i]) data_point_in_a_cluster = "yes" if data_point_in_a_cluster == "no": k += 1 K[k]=[data_points[i]] return K

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  • Is it wrong for a context (right click) menu be the only way a user can perform a certain task?

    - by Eric
    I'd like to know if it ever makes sense to provide some functionality in a piece of software that is only available to the user through a context (right click) menu. It seems that in most software I've worked with the right click menu is always used as a quick way to get to features that are otherwise available from other buttons or menus. Below is a screen shot of the UI I'm developing. The tree view on the right shows the user's library of catalogs. Users can create new catalogs, or add and remove existing catalogs to and from their library. Catalogs in their library can then be opened or closed, or set to read-only. The screen shot shows the context menu I've created for the browser. Some commands can be executed independently from any specific catalog (New, Add). Yet the other commands must be applied to a specifically selected catalog (Close, Open, Remove, ReadOnly, Refresh, Clean UP, Rename). Currently the "Catalog" menu at the top of the window looks identical to this context menu. Yet I think this may be confusing to the users as the tree view which shows the currently selected catalog may not always be visible. The user may have switched to the Search or Filters tab, or the left pane may be hidden entirely. However, I'm hesitant to change the UI so that the commands that depends on a specifically selected catalog are only available through the context menu.

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  • seriouosly elusive for loop (racking my brains!)

    - by user1693359
    I've got a loop issue in Python 2.72 that's really frustrating me. Basically the loop is not iterating fast the first index (j), and I've tried all sorts of ways to fix it with no luck. def learn(dataSet): for i in dataSet.getNext(): recall = raw_input("Enter all members of %s you are able to recall >>> (separated by commas) " % (i.getName())) missed = i.getMembers() missedString = [] for a in missed: missedString.append(a.getName()) Here is the loop I can't get to iterate. The first for loop only goes through the first iteration of 'j' in the split string list, then removes it from 'missedString'. I would like for all members of the split-string 'recall' to be removed from 'missedString'. for j in string.split(recall, ','): if j in missedString: missedString.remove(j) continue for b in missed: if b.getName() not in missedString: missed.remove(b) print 'You missed %d. ' % (len(missed)) if (len(missed)) > 0: print 'Maybe a hint or two will help...' for miss in missed: remind(miss.getSecs(), i.getName(), missed) I really have no clue, help would be appreciated!

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  • Modifying an ObservableCollection using move() ?

    - by user1202434
    I have a question relating to modifying the individual items in an ObservableCollection that is bound to a ListBox in the UI. The user in the UI can multiselect items and then drop them at a particular index to re-order them. So, if I have items {0,1,2,3,4,5,6,7,8,9} the user can choose items 2, 5, 7 (in that order) and choose to drop them at index 3, so that the collection now becomes, {0,1,3, 2, 5, 7, 4, 8,9} The way I have it working now, is like this inside of ondrop() method on my control, I do something like: foreach (Item item in draggedItems) { int oldIndex = collection.IndexOf(item.DataContext as MyItemType); int newIndex = toDropIndex; if (newIndex == collection.Count) { newIndex--; } if (oldIndex != newIndex) { collection.Move(oldIndex, newIndex); } } But the problem is, if I drop the items before the index where i start dragging my first item, the order becomes reversed...so the collection becomes, {0,1,3, 7, 5, 2, 4, 8,9} It works fine if I drop after index 3, but if i drop it before 3 then the order becomes reversed. Now, I can do a simple remove and then insert all items at the index I want to, but "move" for me has the advantage of keeping the selection in the ui (remove basically de-selects the items in the list..)....so I will need to make use of the move method, what is wrong with my method above and how to fix it? Thanks!

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  • any clue in these logs why keyboard audio and internet are messed up

    - by mmj
    Jun 7 00:01:18 Isis lightdm: pam_unix(lightdm-autologin:session): session opened for user mimi by (uid=0) Jun 7 00:01:18 Isis lightdm: pam_ck_connector(lightdm-autologin:session): nox11 mode, ignoring PAM_TTY :0 Jun 7 00:01:26 Isis polkitd(authority=local): Registered Authentication Agent for unix-session:/org/freedesktop/ConsoleKit/Session1 (system bus name :1.36 [/usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1], object path /org/gnome/PolicyKit1/AuthenticationAgent, locale zh_CN.UTF-8) Jun 7 00:01:29 Isis dbus[610]: [system] Rejected send message, 2 matched rules; type="method_call", sender=":1.44" (uid=1000 pid=1763 comm="/usr/lib/indicator-datetime/indicator-datetime-ser") interface="org.freedesktop.DBus.Properties" member="GetAll" error name="(unset)" requested_reply="0" destination=":1.15" (uid=0 pid=1219 comm="/usr/sbin/console-kit-daemon --no-daemon ") Jun 7 00:07:55 Isis sudo: pam_unix(sudo:auth): authentication failure; logname=mimi uid=1000 euid=0 tty=/dev/pts/1 ruser=mimi rhost= user=mimi Jun 7 00:08:11 Isis sudo: mimi : TTY=pts/1 ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/bin/add-apt-repository ppa:colingille/freshlight Jun 7 00:08:11 Isis sudo: pam_unix(sudo:session): session opened for user root by mimi(uid=1000) Jun 7 00:08:32 Isis sudo: pam_unix(sudo:session): session closed for user root Jun 7 00:11:20 Isis sudo: mimi : TTY=pts/1 ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/bin/apt-get install gparted Jun 7 00:11:20 Isis sudo: pam_unix(sudo:session): session opened for user root by mimi(uid=1000) Jun 7 00:11:59 Isis sudo: pam_unix(sudo:session): session closed for user root Jun 7 00:17:02 Isis CRON[2651]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 00:17:02 Isis CRON[2651]: pam_unix(cron:session): session closed for user root Jun 7 00:17:32 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 successfully authenticated as unix-user:mimi to gain ONE-SHOT authorization for action com.ubuntu.pkexec.gparted for unix-process:2655:96838 [/bin/sh /usr/bin/gparted-pkexec] (owned by unix-user:mimi) Jun 7 00:17:32 Isis pkexec: pam_unix(polkit-1:session): session opened for user root by (uid=1000) Jun 7 00:17:32 Isis pkexec: pam_ck_connector(polkit-1:session): cannot determine display-device Jun 7 00:17:32 Isis pkexec[2657]: mimi: Executing command [USER=root] [TTY=unknown] [CWD=/home/mimi] [COMMAND=/usr/sbin/gparted] Jun 7 00:48:15 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 successfully authenticated as unix-user:mimi to gain ONE-SHOT authorization for action com.ubuntu.pkexec.gparted for unix-process:3813:281120 [/bin/sh /usr/bin/gparted-pkexec] (owned by unix-user:mimi) Jun 7 00:48:15 Isis pkexec: pam_unix(polkit-1:session): session opened for user root by (uid=1000) Jun 7 00:48:15 Isis pkexec: pam_ck_connector(polkit-1:session): cannot determine display-device Jun 7 00:48:15 Isis pkexec[3815]: mimi: Executing command [USER=root] [TTY=unknown] [CWD=/home/mimi] [COMMAND=/usr/sbin/gparted] Jun 7 01:17:01 Isis CRON[3960]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 01:17:01 Isis CRON[3960]: pam_unix(cron:session): session closed for user root Jun 7 02:08:52 Isis gnome-screensaver-dialog: gkr-pam: unlocked login keyring Jun 7 02:17:01 Isis CRON[4246]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 02:17:01 Isis CRON[4246]: pam_unix(cron:session): session closed for user root Jun 7 02:17:05 Isis sudo: mimi : TTY=pts/1 ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/bin/apt-get install unetbootin Jun 7 02:17:05 Isis sudo: pam_unix(sudo:session): session opened for user root by mimi(uid=1000) Jun 7 02:17:57 Isis sudo: pam_unix(sudo:session): session closed for user root Jun 7 02:18:59 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 02:18:59 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 02:18:59 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 02:18:59 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 02:18:59 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 02:18:59 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 02:18:59 Isis sudo: mimi : 3 incorrect password attempts ; TTY=unknown ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/bin/unetbootin 'rootcheck=no' Jun 7 02:18:59 Isis sudo: unable to execute /usr/sbin/sendmail: No such file or directory Jun 7 02:19:26 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 02:19:26 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 02:19:26 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 02:19:26 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 02:19:26 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 02:19:26 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 02:19:26 Isis sudo: mimi : 3 incorrect password attempts ; TTY=unknown ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/bin/unetbootin 'rootcheck=no' Jun 7 02:19:26 Isis sudo: unable to execute /usr/sbin/sendmail: No such file or directory Jun 7 02:33:21 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 02:33:21 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 02:33:21 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 02:33:21 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 02:33:21 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 02:33:21 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 02:33:21 Isis sudo: mimi : 3 incorrect password attempts ; TTY=unknown ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/bin/unetbootin 'rootcheck=no' Jun 7 02:33:21 Isis sudo: unable to execute /usr/sbin/sendmail: No such file or directory Jun 7 02:40:04 Isis sudo: mimi : TTY=pts/1 ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/bin/unetbootin rootcheck=no Jun 7 02:40:04 Isis sudo: pam_unix(sudo:session): session opened for user root by mimi(uid=1000) Jun 7 03:17:01 Isis CRON[5506]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 03:17:01 Isis CRON[5506]: pam_unix(cron:session): session closed for user root Jun 7 03:33:24 Isis sudo: pam_unix(sudo:session): session closed for user root Jun 7 03:33:43 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 03:33:43 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 03:33:43 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 03:33:43 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 03:33:43 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 03:33:43 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 03:33:43 Isis sudo: mimi : 3 incorrect password attempts ; TTY=pts/1 ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/bin/unetbootin showall=yes 'rootcheck=no' Jun 7 03:33:43 Isis sudo: unable to execute /usr/sbin/sendmail: No such file or directory Jun 7 04:17:01 Isis CRON[6119]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 04:17:01 Isis CRON[6119]: pam_unix(cron:session): session closed for user root Jun 7 04:18:35 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 successfully authenticated as unix-user:mimi to gain TEMPORARY authorization for action org.debian.apt.install-or-remove-packages for system-bus-name::1.79 [/usr/bin/python /usr/bin/landscape-client-ui-install] (owned by unix-user:mimi) Jun 7 04:19:11 Isis groupadd[6702]: group added to /etc/group: name=landscape, GID=127 Jun 7 04:19:11 Isis groupadd[6702]: group added to /etc/gshadow: name=landscape Jun 7 04:19:11 Isis groupadd[6702]: new group: name=landscape, GID=127 Jun 7 04:19:11 Isis useradd[6706]: new user: name=landscape, UID=115, GID=127, home=/var/lib/landscape, shell=/bin/false Jun 7 04:19:12 Isis usermod[6711]: change user 'landscape' password Jun 7 04:19:12 Isis chage[6716]: changed password expiry for landscape Jun 7 04:19:37 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 FAILED to authenticate to gain authorization for action com.canonical.LandscapeClientSettings.configure for unix-process:6146:1543697 [/usr/bin/python /usr/bin/landscape-client-settings-ui] (owned by unix-user:mimi) Jun 7 04:20:20 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 FAILED to authenticate to gain authorization for action com.canonical.LandscapeClientSettings.configure for unix-process:6832:1555313 [/usr/bin/python /usr/bin/landscape-client-settings-ui] (owned by unix-user:mimi) Jun 7 04:21:04 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 FAILED to authenticate to gain authorization for action com.ubuntu.languageselector.setsystemdefaultlanguage for unix-process:6827:1555123 [/usr/bin/python /usr/bin/gnome-language-selector] (owned by unix-user:mimi) Jun 7 04:21:08 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 FAILED to authenticate to gain authorization for action com.ubuntu.languageselector.setsystemdefaultlanguage for unix-process:6827:1555123 [/usr/bin/python /usr/bin/gnome-language-selector] (owned by unix-user:mimi) Jun 7 04:21:44 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 FAILED to authenticate to gain authorization for action org.debian.apt.install-or-remove-packages for system-bus-name::1.87 [/usr/bin/python /usr/bin/gnome-language-selector] (owned by unix-user:mimi) Jun 7 04:22:27 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 successfully authenticated as unix-user:mimi to gain TEMPORARY authorization for action com.canonical.LandscapeClientSettings.configure for unix-process:7830:1567424 [/usr/bin/python /usr/bin/landscape-client-settings-ui] (owned by unix-user:mimi) Jun 7 04:25:50 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 FAILED to authenticate to gain authorization for action com.ubuntu.languageselector.setsystemdefaultlanguage for unix-process:7876:1584865 [/usr/bin/python /usr/bin/gnome-language-selector] (owned by unix-user:mimi) Jun 7 04:25:52 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 FAILED to authenticate to gain authorization for action com.ubuntu.languageselector.setsystemdefaultlanguage for unix-process:7876:1584865 [/usr/bin/python /usr/bin/gnome-language-selector] (owned by unix-user:mimi) Jun 7 05:11:57 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 successfully authenticated as unix-user:mimi to gain TEMPORARY authorization for action org.debian.apt.install-or-remove-packages for system-bus-name::1.95 [/usr/bin/python /usr/bin/gnome-language-selector] (owned by unix-user:mimi) Jun 7 05:17:02 Isis CRON[8708]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 05:17:02 Isis CRON[8708]: pam_unix(cron:session): session closed for user root Jun 7 05:28:03 Isis lightdm: pam_unix(lightdm-autologin:session): session opened for user mimi by (uid=0) Jun 7 05:28:03 Isis lightdm: pam_ck_connector(lightdm-autologin:session): nox11 mode, ignoring PAM_TTY :0 Jun 7 05:28:17 Isis polkitd(authority=local): Registered Authentication Agent for unix-session:/org/freedesktop/ConsoleKit/Session1 (system bus name :1.32 [/usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1], object path /org/gnome/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) Jun 7 05:28:32 Isis dbus[660]: [system] Rejected send message, 2 matched rules; type="method_call", sender=":1.44" (uid=1000 pid=1736 comm="/usr/lib/indicator-datetime/indicator-datetime-ser") interface="org.freedesktop.DBus.Properties" member="GetAll" error name="(unset)" requested_reply="0" destination=":1.17" (uid=0 pid=1333 comm="/usr/sbin/console-kit-daemon --no-daemon ") Jun 7 06:17:01 Isis CRON[2391]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 06:17:02 Isis CRON[2391]: pam_unix(cron:session): session closed for user root Jun 7 06:25:02 Isis CRON[2492]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 06:25:02 Isis CRON[2492]: pam_unix(cron:session): session closed for user root Jun 7 07:17:01 Isis CRON[3174]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 07:17:01 Isis CRON[3174]: pam_unix(cron:session): session closed for user root Jun 7 07:30:01 Isis CRON[3397]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 07:30:01 Isis CRON[3397]: pam_unix(cron:session): session closed for user root Jun 7 08:09:01 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 08:09:01 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 08:09:01 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 08:09:01 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 08:09:01 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 08:09:01 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 08:09:01 Isis sudo: mimi : 3 incorrect password attempts ; TTY=unknown ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/share/checkbox/backend --path=/usr/share/checkbox/scripts:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games /tmp/checkboxQbuE6V/input /tmp/checkboxQbuE6V/output Jun 7 08:09:01 Isis sudo: unable to execute /usr/sbin/sendmail: No such file or directory Jun 7 08:09:59 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 08:09:59 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 08:09:59 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 08:09:59 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 08:09:59 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 08:09:59 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 08:09:59 Isis sudo: mimi : 3 incorrect password attempts ; TTY=unknown ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/share/checkbox/backend --path=/usr/share/checkbox/scripts:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games /tmp/checkboxQbuE6V/input /tmp/checkboxQbuE6V/output Jun 7 08:09:59 Isis sudo: unable to execute /usr/sbin/sendmail: No such file or directory Jun 7 08:10:55 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 08:10:55 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 08:10:55 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 08:10:55 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 08:10:55 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 08:10:55 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 08:10:55 Isis sudo: mimi : 3 incorrect password attempts ; TTY=unknown ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/share/checkbox/backend --path=/usr/share/checkbox/scripts:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games /tmp/checkboxQbuE6V/input /tmp/checkboxQbuE6V/output Jun 7 08:10:55 Isis sudo: unable to execute /usr/sbin/sendmail: No such file or directory Jun 7 08:17:01 Isis CRON[4215]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 08:17:01 Isis CRON[4215]: pam_unix(cron:session): session closed for user root Jun 7 09:17:02 Isis CRON[4766]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 09:17:02 Isis CRON[4766]: pam_unix(cron:session): session closed for user root Jun 7 10:17:02 Isis CRON[5046]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 10:17:02 Isis CRON[5046]: pam_unix(cron:session): session closed for user root Jun 7 11:17:02 Isis CRON[5325]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 11:17:02 Isis CRON[5325]: pam_unix(cron:session): session closed for user root Jun 7 12:17:01 Isis CRON[5617]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 12:17:01 Isis CRON[5617]: pam_unix(cron:session): session closed for user root Jun 7 13:07:51 Isis gnome-screensaver-dialog: pam_unix(gnome-screensaver:auth): authentication failure; logname= uid=1000 euid=1000 tty=:0.0 ruser= rhost= user=mimi Jun 7 13:07:51 Isis gnome-screensaver-dialog: pam_winbind(gnome-screensaver:auth): getting password (0x00000388) Jun 7 13:07:51 Isis gnome-screensaver-dialog: pam_winbind(gnome-screensaver:auth): pam_get_item returned a password Jun 7 13:07:51 Isis gnome-screensaver-dialog: pam_winbind(gnome-screensaver:auth): request wbcLogonUser failed: WBC_ERR_AUTH_ERROR, PAM error: PAM_USER_UNKNOWN (10), NTSTATUS: NT_STATUS_NO_SUCH_USER, Error message was: No such user Jun 7 13:08:03 Isis gnome-screensaver-dialog: pam_unix(gnome-screensaver:auth): conversation failed Jun 7 13:08:03 Isis gnome-screensaver-dialog: pam_unix(gnome-screensaver:auth): auth could not identify password for [mimi] Jun 7 13:08:03 Isis gnome-screensaver-dialog: pam_winbind(gnome-screensaver:auth): getting password (0x00000388) Jun 7 13:08:08 Isis lightdm: pam_unix(lightdm:session): session opened for user lightdm by (uid=0) Jun 7 13:08:08 Isis lightdm: pam_ck_connector(lightdm:session): nox11 mode, ignoring PAM_TTY :1 Jun 7 13:08:13 Isis lightdm: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "mimi" Jun 7 13:08:16 Isis dbus[660]: [system] Rejected send message, 2 matched rules; type="method_call", sender=":1.91" (uid=104 pid=5961 comm="/usr/lib/indicator-datetime/indicator-datetime-ser") interface="org.freedesktop.DBus.Properties" member="GetAll" error name="(unset)" requested_reply="0" destination=":1.17" (uid=0 pid=1333 comm="/usr/sbin/console-kit-daemon --no-daemon ") Jun 7 13:08:18 Isis dbus[660]: [system] Rejected send message, 2 matched rules; type="method_call", sender=":1.98" (uid=104 pid=5999 comm="/usr/lib/indicator-datetime/indicator-datetime-ser") interface="org.freedesktop.DBus.Properties" member="GetAll" error name="(unset)" requested_reply="0" destination=":1.17" (uid=0 pid=1333 comm="/usr/sbin/console-kit-daemon --no-daemon ") Jun 7 13:10:15 Isis lightdm: pam_unix(lightdm:session): session closed for user lightdm Jun 7 13:17:02 Isis CRON[6181]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 13:17:02 Isis CRON[6181]: pam_unix(cron:session): session closed for user root Jun 7 13:55:14 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 13:55:14 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 13:55:14 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 13:55:14 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 13:55:14 Isis sudo: pam_unix(sudo:auth): conversation failed Jun 7 13:55:14 Isis sudo: pam_unix(sudo:auth): auth could not identify password for [mimi] Jun 7 13:55:14 Isis sudo: mimi : 3 incorrect password attempts ; TTY=unknown ; PWD=/home/mimi ; USER=root ; COMMAND=/usr/bin/unetbootin 'rootcheck=no' Jun 7 13:55:14 Isis sudo: unable to execute /usr/sbin/sendmail: No such file or directory Jun 7 14:02:33 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 FAILED to authenticate to gain authorization for action com.canonical.LandscapeClientSettings.configure for unix-process:6736:3087856 [/usr/bin/python /usr/bin/landscape-client-settings-ui] (owned by unix-user:mimi) Jun 7 14:02:51 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 FAILED to authenticate to gain authorization for action com.canonical.LandscapeClientSettings.configure for unix-process:6752:3089992 [/usr/bin/python /usr/bin/landscape-client-settings-ui] (owned by unix-user:mimi) Jun 7 14:03:14 Isis polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session1 successfully authenticated as unix-user:mimi to gain TEMPORARY authorization for action com.canonical.LandscapeClientSettings.configure for unix-process:6763:3092515 [/usr/bin/python /usr/bin/landscape-client-settings-ui] (owned by unix-user:mimi) Jun 7 14:17:01 Isis CRON[6933]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 14:17:01 Isis CRON[6933]: pam_unix(cron:session): session closed for user root Jun 7 15:17:02 Isis CRON[7611]: pam_unix(cron:session): session opened for user root by (uid=0) Jun 7 15:17:02 Isis CRON[7611]: pam_unix(cron:session): session closed for user root

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  • URL Rewrite – Multiple domains under one site. Part II

    - by OWScott
    I believe I have it … I’ve been meaning to put together the ultimate outgoing rule for hosting multiple domains under one site.  I finally sat down this week and setup a few test cases, and created one rule to rule them all.  In Part I of this two part series, I covered the incoming rule necessary to host a site in a subfolder of a website, while making it appear as if it’s in the root of the site.  Part II won’t work without applying Part I first, so if you haven’t read it, I encourage you to read it now. However, the incoming rule by itself doesn’t address everything.  Here’s the problem … Let’s say that we host www.site2.com in a subfolder called site2, off of masterdomain.com.  This is the same example I used in Part I.   Using an incoming rewrite rule, we are able to make a request to www.site2.com even though the site is really in the /site2 folder.  The gotcha comes with any type of path that ASP.NET generates (I’m sure other scripting technologies could do the same too).  ASP.NET thinks that the path to the root of the site is /site2, but the URL is /.  See the issue?  If ASP.NET generates a path or a redirect for us, it will always add /site2 to the URL.  That results in a path that looks something like www.site2.com/site2.  In Part I, I mentioned that you should add a condition where “{PATH_INFO} ‘does not match’ /site2”.  That allows www.site2.com/site2 and www.site2.com to both function the same.  This allows the site to always work, but if you want to hide /site2 in the URL, you need to take it one step further. One way to address this is in your code.  Ultimately this is the best bet.  Ruslan Yakushev has a great article on a few considerations that you can address in code.  I recommend giving that serious consideration.  Additionally, if you have upgraded to ASP.NET 3.5 SP1 or greater, it takes care of some of the references automatically for you. However, what if you inherit an existing application?  Or you can’t easily go through your existing site and make the code changes?  If this applies to you, read on. That’s where URL Rewrite 2.0 comes in.  With URL Rewrite 2.0, you can create an outgoing rule that will remove the /site2 before the page is sent back to the user.  This means that you can take an existing application, host it in a subfolder of your site, and ensure that the URL never reveals that it’s in a subfolder. Performance Considerations Performance overhead is something to be mindful of.  These outbound rules aren’t simply changing the server variables.  The first rule I’ll cover below needs to parse the HTML body and pull out the path (i.e. /site2) on the way through.  This will add overhead, possibly significant if you have large pages and a busy site.  In other words, your mileage may vary and you may need to test to see the impact that these rules have.  Don’t worry too much though.  For many sites, the performance impact is negligible. So, how do we do it? Creating the Outgoing Rule There are really two things to keep in mind.  First, ASP.NET applications frequently generate a URL that adds the /site2 back into the URL.  In addition to URLs, they can be in form elements, img elements and the like.  The goal is to find all of those situations and rewrite it on the way out.  Let’s call this the ‘URL problem’. Second, and similarly, ASP.NET can send a LOCATION redirect that causes a redirect back to another page.  Again, ASP.NET isn’t aware of the different URL and it will add the /site2 to the redirect.  Form Authentication is a good example on when this occurs.  Try to password protect a site running from a subfolder using forms auth and you’ll quickly find that the URL becomes www.site2.com/site2 again.  Let’s term this the ‘redirect problem’. Solving the URL Problem – Outgoing Rule #1 Let’s create a rule that removes the /site2 from any URL.  We want to remove it from relative URLs like /site2/something, or absolute URLs like http://www.site2.com/site2/something.  Most URLs that ASP.NET creates will be relative URLs, but I figure that there may be some applications that piece together a full URL, so we might as well expect that situation. Let’s get started.  First, create a new outbound rule.  You can create the rule within the /site2 folder which will reduce the performance impact of the rule.  Just a reminder that incoming rules for this situation won’t work in a subfolder … but outgoing rules will. Give it a name that makes sense to you, for example “Outgoing – URL paths”. Precondition.  If you place the rule in the subfolder, it will only run for that site and folder, so there isn’t need for a precondition.  Run it for all requests.  If you place it in the root of the site, you may want to create a precondition for HTTP_HOST = ^(www\.)?site2\.com$. For the Match section, there are a few things to consider.  For performance reasons, it’s best to match the least amount of elements that you need to accomplish the task.  For my test cases, I just needed to rewrite the <a /> tag, but you may need to rewrite any number of HTML elements.  Note that as long as you have the exclude /site2 rule in your incoming rule as I described in Part I, some elements that don’t show their URL—like your images—will work without removing the /site2 from them.  That reduces the processing needed for this rule. Leave the “matching scope” at “Response” and choose the elements that you want to change. Set the pattern to “^(?:site2|(.*//[_a-zA-Z0-9-\.]*)?/site2)(.*)”.  Make sure to replace ‘site2’ with your subfolder name in both places.  Yes, I realize this is a pretty messy looking rule, but it handles a few situations.  This rule will handle the following situations correctly: Original Rewritten using {R:1}{R:2} http://www.site2.com/site2/default.aspx http://www.site2.com/default.aspx http://www.site2.com/folder1/site2/default.aspx Won’t rewrite since it’s a sub-sub folder /site2/default.aspx /default.aspx site2/default.aspx /default.aspx /folder1/site2/default.aspx Won’t rewrite since it’s a sub-sub folder. For the conditions section, you can leave that be. Finally, for the rule, set the Action Type to “Rewrite” and set the Value to “{R:1}{R:2}”.  The {R:1} and {R:2} are back references to the sections within parentheses.  In other words, in http://domain.com/site2/something, {R:1} will be http://domain.com and {R:2} will be /something. If you view your rule from your web.config file (or applicationHost.config if it’s a global rule), it should look like this: <rule name="Outgoing - URL paths" enabled="true"> <match filterByTags="A" pattern="^(?:site2|(.*//[_a-zA-Z0-9-\.]*)?/site2)(.*)" /> <action type="Rewrite" value="{R:1}{R:2}" /> </rule> Solving the Redirect Problem Outgoing Rule #2 The second issue that we can run into is with a client-side redirect.  This is triggered by a LOCATION response header that is sent to the client.  Forms authentication is a common example.  To reproduce this, password protect your subfolder and watch how it redirects and adds the subfolder path back in. Notice in my test case the extra paths: http://site2.com/site2/login.aspx?ReturnUrl=%2fsite2%2fdefault.aspx I want to remove /site2 from both the URL and the ReturnUrl querystring value.  For semi-readability, let’s do this in 2 separate rules, one for the URL and one for the querystring. Create a second rule.  As with the previous rule, it can be created in the /site2 subfolder.  In the URL Rewrite wizard, select Outbound rules –> “Blank Rule”. Fill in the following information: Name response_location URL Precondition Don’t set Match: Matching Scope Server Variable Match: Variable Name RESPONSE_LOCATION Match: Pattern ^(?:site2|(.*//[_a-zA-Z0-9-\.]*)?/site2)(.*) Conditions Don’t set Action Type Rewrite Action Properties {R:1}{R:2} It should end up like so: <rule name="response_location URL"> <match serverVariable="RESPONSE_LOCATION" pattern="^(?:site2|(.*//[_a-zA-Z0-9-\.]*)?/site2)(.*)" /> <action type="Rewrite" value="{R:1}{R:2}" /> </rule> Outgoing Rule #3 Outgoing Rule #2 only takes care of the URL path, and not the querystring path.  Let’s create one final rule to take care of the path in the querystring to ensure that ReturnUrl=%2fsite2%2fdefault.aspx gets rewritten to ReturnUrl=%2fdefault.aspx. The %2f is the HTML encoding for forward slash (/). Create a rule like the previous one, but with the following settings: Name response_location querystring Precondition Don’t set Match: Matching Scope Server Variable Match: Variable Name RESPONSE_LOCATION Match: Pattern (.*)%2fsite2(.*) Conditions Don’t set Action Type Rewrite Action Properties {R:1}{R:2} The config should look like this: <rule name="response_location querystring"> <match serverVariable="RESPONSE_LOCATION" pattern="(.*)%2fsite2(.*)" /> <action type="Rewrite" value="{R:1}{R:2}" /> </rule> It’s possible to squeeze the last two rules into one, but it gets kind of confusing so I felt that it’s better to show it as two separate rules. Summary With the rules covered in these two parts, we’re able to have a site in a subfolder and make it appear as if it’s in the root of the site.  Not only that, we can overcome automatic redirecting that is caused by ASP.NET, other scripting technologies, and especially existing applications. Following is an example of the incoming and outgoing rules necessary for a site called www.site2.com hosted in a subfolder called /site2.  Remember that the outgoing rules can be placed in the /site2 folder instead of the in the root of the site. <rewrite> <rules> <rule name="site2.com in a subfolder" enabled="true" stopProcessing="true"> <match url=".*" /> <conditions logicalGrouping="MatchAll" trackAllCaptures="false"> <add input="{HTTP_HOST}" pattern="^(www\.)?site2\.com$" /> <add input="{PATH_INFO}" pattern="^/site2($|/)" negate="true" /> </conditions> <action type="Rewrite" url="/site2/{R:0}" /> </rule> </rules> <outboundRules> <rule name="Outgoing - URL paths" enabled="true"> <match filterByTags="A" pattern="^(?:site2|(.*//[_a-zA-Z0-9-\.]*)?/site2)(.*)" /> <action type="Rewrite" value="{R:1}{R:2}" /> </rule> <rule name="response_location URL"> <match serverVariable="RESPONSE_LOCATION" pattern="^(?:site2|(.*//[_a-zA-Z0-9-\.]*)?/site2)(.*)" /> <action type="Rewrite" value="{R:1}{R:2}" /> </rule> <rule name="response_location querystring"> <match serverVariable="RESPONSE_LOCATION" pattern="(.*)%2fsite2(.*)" /> <action type="Rewrite" value="{R:1}{R:2}" /> </rule> </outboundRules> </rewrite> If you run into any situations that aren’t caught by these rules, please let me know so I can update this to be as complete as possible. Happy URL Rewriting!

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  • Jolicloud is a Nifty New OS for Your Netbook

    - by Matthew Guay
    Want to breathe new life into your netbook?  Here’s a quick look at Jolicloud, a unique new Linux based OS that lets you use your netbook in a whole new way. Netbooks have been an interesting category of computers.  When they were first released, most netbooks came with a stripped down Linux based operating system designed to let you easily access the internet first and foremost.  Consumers wanted more from their netbooks, so full OSes such as Windows XP and Ubuntu became the standard on netbooks.  Microsoft worked hard to get Windows 7 working great on netbooks, and today most netbooks run Windows 7 great.  But the Linux community hasn’t stood still either, and Jolicloud is proof of that.  Jolicloud is a unique OS designed to bring the best of both webapps and standard programs to your netbook.   Keep reading to see if this is the perfect netbook OS for you. Getting Started Installing Jolicloud on your netbook is easy thanks to a the Jolicloud Express installer for Windows.  Since many netbooks run Windows by default, this makes it easy to install Jolicloud.  Plus, your Windows install is left untouched, so you can still easily access all your Windows files and programs. Download and run the roughly 700Mb installer (link below) just as a normal installer in Windows. This will first extract the needed files. Click Get started to install Jolicloud on your netbook. Enter a username, password, and nickname for your computer.  Please note that the username must be all lowercase, and the nickname should not contain spaces or special characters.   Now you can review the default installation settings.  By default it will take up 39Gb and install on your C:\ drive in English.  If you wish to change this, click Change. We chose to install it on the D: drive on this netbook, as its harddrive was already partitioned into two parts.  Click Save when your settings are all correct, and then click Next in the previous window. Jolicloud will prepare for the installation.  This took about 5 minutes in our test.  Click Next when this is finished. Click Restart now to install and run Jolicloud. When your netbook reboots, it will initialize the Jolicloud setup. It will then automatically finish the installation.  Just sit back and wait; there’s nothing for you to do right now.  The installation took about 20 minutes in our test. Jolicloud will automatically reboot when the setup is finished. Once it’s rebooted, you’re ready to go!  Enter the username, then the password, that you chose earlier when you were installing Jolicloud from Windows. Welcome to your Jolicloud desktop! Hardware Support We installed Jolicloud on a Samsung N150 netbook with an Atom N450 processor, 1Gb Ram, 250Gb harddrive, and WiFi b/g/n with Bluetooth.  Amazingly, once Jolicloud was installed, everything was ready to use.  No drivers to install, no settings to hassle with, it was all installed and set up perfectly.  Power settings worked great, and closing the netbook put it to sleep just like in Windows. WiFi drivers have typically been difficult to find and install on Linux, but Jolicloud had our netbook’s wifi working immediately.  To get online, simply click the Wireless icon on the top right, and select the wireless network you want to connect to. Jolicloud will let you know when it is signed on. Wired Lan networking was also seamless; simply connect your cable and you’re ready to go.  The webcam and touchpad also worked perfectly directly.  The only thing missing was multitouch; this touchpad has two finger scroll, pinch zoom, and other nice multitouch features in Windows, but in Julicloud it only functioned as a standard touchpad.  It did have tap to click activated by default, as well as right-side scrolling, which is nice. Jolicloud also supported our video card without any extra work.  The native resolution was already selected, and the only problem we had with the screen was that there was no apparent way to change the brightness.  This is not a major problem, but would be nice to have.  The Samsung N150 has Intel GMA3150 integrated graphics, and Jolicloud promises 1080p HD video on it.  It did playback 720p H.264 video flawlessly without installing anything extra, but it stuttered on full 1080p HD (which is the exact same as this netbook’s video playback in Windows 7 – 720p works great, but it stutters on 1080p).  We would be excited to see full HD on this netbook, but 720p is definitely fine for most stuff.   Jolicloud supports a wide range of netbooks, and based on our experience we would expect it to work as good on any supported hardware.  Check out the list of supported netbooks to see if your netbook is supported; if not, it still may work but you may have to install special drivers. Jolicloud’s performance was very similar to Windows 7 on our netbook.  It boots in about 30 seconds, and apps load fairly quickly.  In general, we couldn’t tell much difference in performance between Jolicloud and Windows 7, though this isn’t a problem since Windows 7 runs great on the current generation of netbooks. Using Jolicloud Ready to start putting Jolicloud to use?  Your fresh Jolicloud install you can run several built-in apps, such as Firefox, a calculator, and the chat client Pidgin.  It also has a media player and file viewer installed, so you can play MP3s or MPG videos, or read PDF ebooks without installing anything extra.  It also has Flash player installed so you can watch videos online easily. You can also directly access all of your files from the right side of your home screen.  You can even access your Windows files; in our test, the 116.9 GB Media was C: from Windows.  Select it to browse and open any file you had saved in Windows. You may need to enter your password to access it. Once you’re authenticated it, you’ll see all of your Windows files and folders.  Your User files (Documents, Music, Videos, etc.) will be in the Users folder. And, you can easily add files from removable media such as USB flash drives and memory cards.  Jolicloud recognized a flash drive we tested with no trouble at all. Add new apps But, the best part about Jolicloud is that it makes it very easy to install new apps.  Click the Get Started button on your homescreen. You’ll first need to create an account.  You can then use this same account on another netbook if you wish, and your settings will automatically be synced between the two. You can either signup using your Facebook account, …or you can sign up the traditional way with your email address, name, and password.  If you sign up this way, you will need to confirm your email address before your account will be finished. Now, choose your netbook model from the list, and enter a name for your computer. And that’s it!  You’ll now see the Jolicloud dashboard, which will show you updates and notifications from friends who also use Jolicloud. Click the App directory to find new apps for your netbook.  Here you will find a variety of webapps, such as Gmail, along with native applications, such as Skype, that you can install on your netbook.  Simply click the Install button on the right to add the app to your netbook. You will be prompted to enter your system password, and then the app will install without any further input.   Once an app is installed, a check mark will appear beside its name.  You can remove it by clicking the Remove button, and it will uninstall seamlessly. Webapps, such as Gmail, actually run in in a Chrome-powered window that lets the webapp run full screen.  This gives the webapps a native feel, but actually they’re just running the same as they would in a standard web browser.   The Jolicloud Interface Most apps run maximized, and there is no way to run them smaller.  This in general works good, since with small screens most apps need to run full-screen anyhow. Smaller apps, such as a calculator or the Pidgin chat client, run in a window just like they do on other operating systems. You can switch to another app that’s running by selecting it’s icon on the top left, or you can go back to the home screen by clicking the home screen.  If you’re finished with an program, simply click the red X button on the top right of the window when you’re running it. Or, you can switch between programs using standard keyboard shortcuts such as Alt-tab. The default page on the home screen is the favorites page, and all of your other programs are orginized in their own sections on the left hand side.  But, if you want to add one of these to your favorites page, simply right-click on it and select Add to Favorites. When you’re done for the day, you can simply close your netbook to put it to sleep.  Or, if you want to shut down, just press the Quit button on the bottom right of the home screen and then select Shut Down. Booting Jolicloud When you install Jolicloud, it will set itself as the default operating system.  Now, when you boot your netbook, it will show you a list of installed operating systems.  You can select either Windows or Jolicloud, but if you don’t make a selection it will boot into Jolicloud after waiting 10 seconds. If you’d perfer to boot into Windows by default, you can easily change this.  First, boot your netbook in to Windows.  Open the start menu, right-click on the Computer button, and select Properties.   Click the “Advanced system settings” link on the left side. Click the Settings button in the Startup and Recovery section. Now, select Windows as the default operating system, and click Ok.  Your netbook will now boot into Windows by default, but will give you 10 seconds to choose to boot into Jolicloud when you start your computer. Or, if you decided you don’t want Jolicloud, you can easily uninstall it from within Windows. Please note that this will also remove any files you may have saved in Jolicloud, so be sure to copy them to your Windows drive before uninstalling. To uninstall Jolicloud from within Windows, open Control Panel, and select Uninstall a Program. Scroll down to select Jolicloud, and click Uninstall/Change. Click Yes to confirm that you want to uninstall Jolicloud. After a few moments, it will let you know that Jolicloud has been uninstalled.  You’re netbook is now back the same as it was before you installed Jolicloud, with only Windows installed. Closing Whether you’re wanting to replace your current OS on your netbook or would simply like to try out a fresh new Linux version on your netbook, Jolicloud is a great option for you.  We were very impressed by it’s solid hardware support and the ease of installing new apps in Jolicloud.  Rather than simply giving us a standard OS, Jolicloud offers a unique way to use your netbook with native programs and webapps.  And whether you’re an IT pro or are a new computer user, Jolicloud was easy enough to use that anyone can do it.  Give it a try, and let us know what your favorite netbook OS is! Link Download Jolicloud for your netbook Similar Articles Productive Geek Tips How To Change XSplash Themes in Ubuntu 9.10Verify the Integrity of Windows Vista System FilesMonitor Multiple Logs in a Single Shell with MultiTail for LinuxHide Some or All of the GUI Bars in FirefoxAsk the Readers: Do You Use a Laptop, Desktop, or Both? TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Stop In The Name Of Love (Firefox addon) Chitika iPad Labs Gives Live iPad Sale Stats Heaven & Hell Finder Icon Using TrueCrypt to Secure Your Data Quickly Schedule Meetings With NeedtoMeet Share Flickr Photos On Facebook Automatically

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  • LLBLGen Pro feature highlights: automatic element name construction

    - by FransBouma
    (This post is part of a series of posts about features of the LLBLGen Pro system) One of the things one might take for granted but which has a huge impact on the time spent in an entity modeling environment is the way the system creates names for elements out of the information provided, in short: automatic element name construction. Element names are created in both directions of modeling: database first and model first and the more names the system can create for you without you having to rename them, the better. LLBLGen Pro has a rich, fine grained system for creating element names out of the meta-data available, which I'll describe more in detail below. First the model element related element naming features are highlighted, in the section Automatic model element naming features and after that I'll go more into detail about the relational model element naming features LLBLGen Pro has to offer in the section Automatic relational model element naming features. Automatic model element naming features When working database first, the element names in the model, e.g. entity names, entity field names and so on, are in general determined from the relational model element (e.g. table, table field) they're mapped on, as the model elements are reverse engineered from these relational model elements. It doesn't take rocket science to automatically name an entity Customer if the entity was created after reverse engineering a table named Customer. It gets a little trickier when the entity which was created by reverse engineering a table called TBL_ORDER_LINES has to be named 'OrderLine' automatically. Automatic model element naming also takes into effect with model first development, where some settings are used to provide you with a default name, e.g. in the case of navigator name creation when you create a new relationship. The features below are available to you in the Project Settings. Open Project Settings on a loaded project and navigate to Conventions -> Element Name Construction. Strippers! The above example 'TBL_ORDER_LINES' shows that some parts of the table name might not be needed for name creation, in this case the 'TBL_' prefix. Some 'brilliant' DBAs even add suffixes to table names, fragments you might not want to appear in the entity names. LLBLGen Pro offers you to define both prefix and suffix fragments to strip off of table, view, stored procedure, parameter, table field and view field names. In the example above, the fragment 'TBL_' is a good candidate for such a strip pattern. You can specify more than one pattern for e.g. the table prefix strip pattern, so even a really messy schema can still be used to produce clean names. Underscores Be Gone Another thing you might get rid of are underscores. After all, most naming schemes for entities and their classes use PasCal casing rules and don't allow for underscores to appear. LLBLGen Pro can automatically strip out underscores for you. It's an optional feature, so if you like the underscores, you're not forced to see them go: LLBLGen Pro will leave them alone when ordered to to so. PasCal everywhere... or not, your call LLBLGen Pro can automatically PasCal case names on word breaks. It determines word breaks in a couple of ways: a space marks a word break, an underscore marks a word break and a case difference marks a word break. It will remove spaces in all cases, and based on the underscore removal setting, keep or remove the underscores, and upper-case the first character of a word break fragment, and lower case the rest. Say, we keep the defaults, which is remove underscores and PasCal case always and strip the TBL_ fragment, we get with our example TBL_ORDER_LINES, after stripping TBL_ from the table name two word fragments: ORDER and LINES. The underscores are removed, the first character of each fragment is upper-cased, the rest lower-cased, so this results in OrderLines. Almost there! Pluralization and Singularization In general entity names are singular, like Customer or OrderLine so LLBLGen Pro offers a way to singularize the names. This will convert OrderLines, the result we got after the PasCal casing functionality, into OrderLine, exactly what we're after. Show me the patterns! There are other situations in which you want more flexibility. Say, you have an entity Customer and an entity Order and there's a foreign key constraint defined from the target of Order and the target of Customer. This foreign key constraint results in a 1:n relationship between the entities Customer and Order. A relationship has navigators mapped onto the relationship in both entities the relationship is between. For this particular relationship we'd like to have Customer as navigator in Order and Orders as navigator in Customer, so the relationship becomes Customer.Orders 1:n Order.Customer. To control the naming of these navigators for the various relationship types, LLBLGen Pro defines a set of patterns which allow you, using macros, to define how the auto-created navigator names will look like. For example, if you rather have Customer.OrderCollection, you can do so, by changing the pattern from {$EndEntityName$P} to {$EndEntityName}Collection. The $P directive makes sure the name is pluralized, which is not what you want if you're going for <EntityName>Collection, hence it's removed. When working model first, it's a given you'll create foreign key fields along the way when you define relationships. For example, you've defined two entities: Customer and Order, and they have their fields setup properly. Now you want to define a relationship between them. This will automatically create a foreign key field in the Order entity, which reflects the value of the PK field in Customer. (No worries if you hate the foreign key fields in your classes, on NHibernate and EF these can be hidden in the generated code if you want to). A specific pattern is available for you to direct LLBLGen Pro how to name this foreign key field. For example, if all your entities have Id as PK field, you might want to have a different name than Id as foreign key field. In our Customer - Order example, you might want to have CustomerId instead as foreign key name in Order. The pattern for foreign key fields gives you that freedom. Abbreviations... make sense of OrdNr and friends I already described word breaks in the PasCal casing paragraph, how they're used for the PasCal casing in the constructed name. Word breaks are used for another neat feature LLBLGen Pro has to offer: abbreviation support. Burt, your friendly DBA in the dungeons below the office has a hate-hate relationship with his keyboard: he can't stand it: typing is something he avoids like the plague. This has resulted in tables and fields which have names which are very short, but also very unreadable. Example: our TBL_ORDER_LINES example has a lovely field called ORD_NR. What you would like to see in your fancy new OrderLine entity mapped onto this table is a field called OrderNumber, not a field called OrdNr. What you also like is to not have to rename that field manually. There are better things to do with your time, after all. LLBLGen Pro has you covered. All it takes is to define some abbreviation - full word pairs and during reverse engineering model elements from tables/views, LLBLGen Pro will take care of the rest. For the ORD_NR field, you need two values: ORD as abbreviation and Order as full word, and NR as abbreviation and Number as full word. LLBLGen Pro will now convert every word fragment found with the word breaks which matches an abbreviation to the given full word. They're case sensitive and can be found in the Project Settings: Navigate to Conventions -> Element Name Construction -> Abbreviations. Automatic relational model element naming features Not everyone works database first: it may very well be the case you start from scratch, or have to add additional tables to an existing database. For these situations, it's key you have the flexibility that you can control the created table names and table fields without any work: let the designer create these names based on the entity model you defined and a set of rules. LLBLGen Pro offers several features in this area, which are described in more detail below. These features are found in Project Settings: navigate to Conventions -> Model First Development. Underscores, welcome back! Not every database is case insensitive, and not every organization requires PasCal cased table/field names, some demand all lower or all uppercase names with underscores at word breaks. Say you create an entity model with an entity called OrderLine. You work with Oracle and your organization requires underscores at word breaks: a table created from OrderLine should be called ORDER_LINE. LLBLGen Pro allows you to do that: with a simple checkbox you can order LLBLGen Pro to insert an underscore at each word break for the type of database you're working with: case sensitive or case insensitive. Checking the checkbox Insert underscore at word break case insensitive dbs will let LLBLGen Pro create a table from the entity called Order_Line. Half-way there, as there are still lower case characters there and you need all caps. No worries, see below Casing directives so everyone can sleep well at night For case sensitive databases and case insensitive databases there is one setting for each of them which controls the casing of the name created from a model element (e.g. a table created from an entity definition using the auto-mapping feature). The settings can have the following values: AsProjectElement, AllUpperCase or AllLowerCase. AsProjectElement is the default, and it keeps the casing as-is. In our example, we need to get all upper case characters, so we select AllUpperCase for the setting for case sensitive databases. This will produce the name ORDER_LINE. Sequence naming after a pattern Some databases support sequences, and using model-first development it's key to have sequences, when needed, to be created automatically and if possible using a name which shows where they're used. Say you have an entity Order and you want to have the PK values be created by the database using a sequence. The database you're using supports sequences (e.g. Oracle) and as you want all numeric PK fields to be sequenced, you have enabled this by the setting Auto assign sequences to integer pks. When you're using LLBLGen Pro's auto-map feature, to create new tables and constraints from the model, it will create a new table, ORDER, based on your settings I previously discussed above, with a PK field ID and it also creates a sequence, SEQ_ORDER, which is auto-assigns to the ID field mapping. The name of the sequence is created by using a pattern, defined in the Model First Development setting Sequence pattern, which uses plain text and macros like with the other patterns previously discussed. Grouping and schemas When you start from scratch, and you're working model first, the tables created by LLBLGen Pro will be in a catalog and / or schema created by LLBLGen Pro as well. If you use LLBLGen Pro's grouping feature, which allows you to group entities and other model elements into groups in the project (described in a future blog post), you might want to have that group name reflected in the schema name the targets of the model elements are in. Say you have a model with a group CRM and a group HRM, both with entities unique for these groups, e.g. Employee in HRM, Customer in CRM. When auto-mapping this model to create tables, you might want to have the table created for Employee in the HRM schema but the table created for Customer in the CRM schema. LLBLGen Pro will do just that when you check the setting Set schema name after group name to true (default). This gives you total control over where what is placed in the database from your model. But I want plural table names... and TBL_ prefixes! For now we follow best practices which suggest singular table names and no prefixes/suffixes for names. Of course that won't keep everyone happy, so we're looking into making it possible to have that in a future version. Conclusion LLBLGen Pro offers a variety of options to let the modeling system do as much work for you as possible. Hopefully you enjoyed this little highlight post and that it has given you new insights in the smaller features available to you in LLBLGen Pro, ones you might not have thought off in the first place. Enjoy!

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  • CodePlex Daily Summary for Wednesday, June 02, 2010

    CodePlex Daily Summary for Wednesday, June 02, 2010New ProjectsBackupCleaner.Net: A C#.Net-based tool for automatically removing old backups selectively. It can be used when you already make daily backups on disk, and want to cle...C# Dotnetnuke Module development Template for Visual Studio 2010: C# DNN Module Development template for Visual Studio 2010 Get a head-start on DNN Module development. Whether you're a pro or just starting with D...Christoc's DotNetNuke C# Module Development Template: A quick and easy to use C# Module development template for DotNetNuke 5, Visual Studio 2008.Client per la digitalizzazione di documenti integrato con DotNetNuke: Questo applicativo in ambiente windows 32bit consente di digitalizzare documenti con piu scanner contemporaneamente, processare OCR in 17 Lingue (p...ContainerOne - C# application server: An application server completely written in c# (.net 4.0).Drop7 Silverlight: It's a clone of the original Drop7 written in Silverlight (C#). Echo.Net: Echo.Net is an embedded task manager for web and windows apps. It allows for simple management of background tasks at specific times. It's develope...energy: Smartgrid Demand Response ImplementationGenerate Twitter Message for Live Writer: This is a plug-in for Windows Live Writer that generates a twitter message with your blog post name and a TinyUrl link to the blog post. It will d...HomingCMS.Net: A lightweight cms.Information Système & Shell à distance: Un web service qui permet d'avoir des informations sur le système et de lancer de commande (terminal) à distance.Javascript And Jquery: gqq's javascript and jquery examplesMemory++: "Tweak the memory to speed up your computer" Memory ++ is basically an application that will speed up your computer ensuring comfort in their norma...Microformat Parsers for .NET: Microformat's Parsers for .NET helps you to collect information you run into on the web, that is stored by means of microformats. It's written in C...MoneyManager: Trying to make Personal Finances management System for my needs. Microsoft stopped to support MSMoney - it makes me so sad, so I wanna to make my ...Open source software for running a financial markets trading business: The core conceptual model will support running a business in the financial markets, for example running a trading exchange business.Ovik: Open Video Converter with simple and intuitive interface for converting video files to the open formats.Oxygen Smil Player: The <project name> is a open a-smil player implementation that is meaned to be connected to a Digital Signage CMS like Oxygen media platform ( www....Protect The Carrot: Protect The Carrot is a small fastpaced XNA game. You are a farmer whose single carrot is under attack by ravenous rabbits. You have to shoot the r...Race Day Commander: The core project is designed to support coaches of "long distance" or "endurance" sporting events coach their athletes during a race. The idea bein...Raygun Diplomacy: Raygun Diplomacy is an action shooter sandbox game set in a futuristic world. It will use procedural generation for the world, weapons, and vehicle...Resx-Translator-Bot: Resx-Translator-Bot uses Google Tanslate to automatically translate the .resx-files in your .NET and ASP.NET applications.Sistema de Expedición del Permiso Único de Siembra: Sistema de Expedición del Permiso Único de Siembra.SiteOA: 一个基于asp.net mvc2的OAStraighce: This is a low-featured, cyclic (log files reside in appname\1.txt to at mose 31.txt), thread-safe and non-blocking TraceListener with some extensio...Touch Mice: Touch Mice turns multiple mice on a computer into individual touch devices. This allows you to create multi-touch applications using the new touch...TStringValidator: A project helper to validate strings. Use this class to hold your regex strings for use with any project's string validation.Ultimate Dotnetnuke Skin Object: Ultimate Skin Object is a Dotnetnuke 5.4.2+ extension that will allow you to easily change your skins doc type, remove unneeded css files, inject e...Ventosus: Ventosus is an upcoming partially text-based game. No further information is available at this time.vit: vit based on asp.net mvcW7 Auto Playlist Generator: Purpose: This application is designed to create W7MC playlist automatically whenever you want. You can select if you want the playlist sorted Alpha...W7 Video Playlist Creator: Purpose: This program allows you to quickly create wvx video play list for Windows Media Center. This functionality is not included in WMC and is u...New ReleasesBCryptTool: BCryptTool v0.2.1: The Microsoft .NET Framework 4.0 is needed to run this program.BFBC2 PRoCon: PRoCon 0.5.2.0: Notes available on phogue.netC# Dotnetnuke Module development Template for Visual Studio 2010: DNNModule 1.0: This is the initial release of DNNModule as was available for download from http://www.subodh.com/Projects/DNNModule In this release: Contains one...Client per la digitalizzazione di documenti integrato con DotNetNuke: Versione 3.0.1: Versione 3.0.1CommonLibrary.NET: CommonLibrary.NET 0.9.4 - Final Release: A collection of very reusable code and components in C# 3.5 ranging from ActiveRecord, Csv, Command Line Parsing, Configuration, Holiday Calendars,...Community Forums NNTP bridge: Community Forums NNTP Bridge V20: Release of the Community Forums NNTP Bridge to access the social and anwsers MS forums with a single, open source NNTP bridge. 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  • Minecraft Style Chunk building problem

    - by David Torrey
    I'm having some problems with speed in my chunk engine. I timed it out, and in its current state it takes a total ~5 seconds per chunk to fill each face's list. I have a check to see if each face of a block is visible and if it is not visible, it skips it and moves on. I'm using a dictionary (unordered map) because it makes sense memorywise to just not have an entry if there is no block. I've tracked my problem down to testing if there is an entry, and accessing an entry if it does exist. If I remove the tests to see if there is an entry in the dictionary for an adjacent block, or if the block type itself is seethrough, it runs within about 2-4 milliseconds. so here's my question: Is there a faster way to check for an entry in a dictionary than .ContainsKey()? As an aside, I tried TryGetValue() and it doesn't really help with the speed that much. If I remove the ContainsKey() and keep the test where it does the IsSeeThrough for each block, it halves the time, but it's still about 2-3 seconds. It only drops to 2-4ms if I remove BOTH checks. Here is my code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Runtime.InteropServices; using OpenTK; using OpenTK.Graphics.OpenGL; using System.Drawing; namespace Anabelle_Lee { public enum BlockEnum { air = 0, dirt = 1, } [StructLayout(LayoutKind.Sequential,Pack=1)] public struct Coordinates<T1> { public T1 x; public T1 y; public T1 z; public override string ToString() { return "(" + x + "," + y + "," + z + ") : " + typeof(T1); } } public struct Sides<T1> { public T1 left; public T1 right; public T1 top; public T1 bottom; public T1 front; public T1 back; } public class Block { public int blockType; public bool SeeThrough() { switch (blockType) { case 0: return true; } return false ; } public override string ToString() { return ((BlockEnum)(blockType)).ToString(); } } class Chunk { private Dictionary<Coordinates<byte>, Block> mChunkData; //stores the block data private Sides<List<Coordinates<byte>>> mVBOVertexBuffer; private Sides<int> mVBOHandle; //private bool mIsChanged; private const byte mCHUNKSIZE = 16; public Chunk() { } public void InitializeChunk() { //create VBO references #if DEBUG Console.WriteLine ("Initializing Chunk"); #endif mChunkData = new Dictionary<Coordinates<byte> , Block>(); //mIsChanged = true; GL.GenBuffers(1, out mVBOHandle.left); GL.GenBuffers(1, out mVBOHandle.right); GL.GenBuffers(1, out mVBOHandle.top); GL.GenBuffers(1, out mVBOHandle.bottom); GL.GenBuffers(1, out mVBOHandle.front); GL.GenBuffers(1, out mVBOHandle.back); //make new list of vertexes for each face mVBOVertexBuffer.top = new List<Coordinates<byte>>(); mVBOVertexBuffer.bottom = new List<Coordinates<byte>>(); mVBOVertexBuffer.left = new List<Coordinates<byte>>(); mVBOVertexBuffer.right = new List<Coordinates<byte>>(); mVBOVertexBuffer.front = new List<Coordinates<byte>>(); mVBOVertexBuffer.back = new List<Coordinates<byte>>(); #if DEBUG Console.WriteLine("Chunk Initialized"); #endif } public void GenerateChunk() { #if DEBUG Console.WriteLine("Generating Chunk"); #endif for (byte i = 0; i < mCHUNKSIZE; i++) { for (byte j = 0; j < mCHUNKSIZE; j++) { for (byte k = 0; k < mCHUNKSIZE; k++) { Random blockLoc = new Random(); Coordinates<byte> randChunk = new Coordinates<byte> { x = i, y = j, z = k }; mChunkData.Add(randChunk, new Block()); mChunkData[randChunk].blockType = blockLoc.Next(0, 1); } } } #if DEBUG Console.WriteLine("Chunk Generated"); #endif } public void DeleteChunk() { //delete VBO references #if DEBUG Console.WriteLine("Deleting Chunk"); #endif GL.DeleteBuffers(1, ref mVBOHandle.left); GL.DeleteBuffers(1, ref mVBOHandle.right); GL.DeleteBuffers(1, ref mVBOHandle.top); GL.DeleteBuffers(1, ref mVBOHandle.bottom); GL.DeleteBuffers(1, ref mVBOHandle.front); GL.DeleteBuffers(1, ref mVBOHandle.back); //clear all vertex buffers ClearPolyLists(); #if DEBUG Console.WriteLine("Chunk Deleted"); #endif } public void UpdateChunk() { #if DEBUG Console.WriteLine("Updating Chunk"); #endif ClearPolyLists(); //prepare buffers //for every entry in mChunkData map foreach(KeyValuePair<Coordinates<byte>,Block> feBlockData in mChunkData) { Coordinates<byte> checkBlock = new Coordinates<byte> { x = feBlockData.Key.x, y = feBlockData.Key.y, z = feBlockData.Key.z }; //check for polygonson the left side of the cube if (checkBlock.x > 0) { //check to see if there is a key for current x - 1. if not, add the vector if (!IsVisible(checkBlock.x - 1, checkBlock.y, checkBlock.z)) { //add polygon AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.left); } } else { //polygon is far left and should be added AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.left); } //check for polygons on the right side of the cube if (checkBlock.x < mCHUNKSIZE - 1) { if (!IsVisible(checkBlock.x + 1, checkBlock.y, checkBlock.z)) { //add poly AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.right); } } else { //poly for right add AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.right); } if (checkBlock.y > 0) { //check to see if there is a key for current x - 1. if not, add the vector if (!IsVisible(checkBlock.x, checkBlock.y - 1, checkBlock.z)) { //add polygon AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.bottom); } } else { //polygon is far left and should be added AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.bottom); } //check for polygons on the right side of the cube if (checkBlock.y < mCHUNKSIZE - 1) { if (!IsVisible(checkBlock.x, checkBlock.y + 1, checkBlock.z)) { //add poly AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.top); } } else { //poly for right add AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.top); } if (checkBlock.z > 0) { //check to see if there is a key for current x - 1. if not, add the vector if (!IsVisible(checkBlock.x, checkBlock.y, checkBlock.z - 1)) { //add polygon AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.back); } } else { //polygon is far left and should be added AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.back); } //check for polygons on the right side of the cube if (checkBlock.z < mCHUNKSIZE - 1) { if (!IsVisible(checkBlock.x, checkBlock.y, checkBlock.z + 1)) { //add poly AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.front); } } else { //poly for right add AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.front); } } BuildBuffers(); #if DEBUG Console.WriteLine("Chunk Updated"); #endif } public void RenderChunk() { } public void LoadChunk() { #if DEBUG Console.WriteLine("Loading Chunk"); #endif #if DEBUG Console.WriteLine("Chunk Deleted"); #endif } public void SaveChunk() { #if DEBUG Console.WriteLine("Saving Chunk"); #endif #if DEBUG Console.WriteLine("Chunk Saved"); #endif } private bool IsVisible(int pX,int pY,int pZ) { Block testBlock; Coordinates<byte> checkBlock = new Coordinates<byte> { x = Convert.ToByte(pX), y = Convert.ToByte(pY), z = Convert.ToByte(pZ) }; if (mChunkData.TryGetValue(checkBlock,out testBlock )) //if data exists { if (testBlock.SeeThrough() == true) //if existing data is not seethrough { return true; } } return true; } private void AddPoly(byte pX, byte pY, byte pZ, int BufferSide) { //create temp array GL.BindBuffer(BufferTarget.ArrayBuffer, BufferSide); if (BufferSide == mVBOHandle.front) { //front face mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ + 1) }); } else if (BufferSide == mVBOHandle.right) { //back face mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); } else if (BufferSide == mVBOHandle.top) { //left face mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY + 1), z = (byte)(pZ) }); } else if (BufferSide == mVBOHandle.bottom) { //right face mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); } else if (BufferSide == mVBOHandle.front) { //top face mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ) }); } else if (BufferSide == mVBOHandle.back) { //bottom face mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY), z = (byte)(pZ + 1) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY), z = (byte)(pZ) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY), z = (byte)(pZ) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY), z = (byte)(pZ) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY), z = (byte)(pZ + 1) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY), z = (byte)(pZ + 1) }); } } private void BuildBuffers() { #if DEBUG Console.WriteLine("Building Chunk Buffers"); #endif GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.front); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.front.Count), mVBOVertexBuffer.front.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.back); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.back.Count), mVBOVertexBuffer.back.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.left); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.left.Count), mVBOVertexBuffer.left.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.right); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.right.Count), mVBOVertexBuffer.right.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.top); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.top.Count), mVBOVertexBuffer.top.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.bottom); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.bottom.Count), mVBOVertexBuffer.bottom.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer,0); #if DEBUG Console.WriteLine("Chunk Buffers Built"); #endif } private void ClearPolyLists() { #if DEBUG Console.WriteLine("Clearing Polygon Lists"); #endif mVBOVertexBuffer.top.Clear(); mVBOVertexBuffer.bottom.Clear(); mVBOVertexBuffer.left.Clear(); mVBOVertexBuffer.right.Clear(); mVBOVertexBuffer.front.Clear(); mVBOVertexBuffer.back.Clear(); #if DEBUG Console.WriteLine("Polygon Lists Cleared"); #endif } }//END CLASS }//END NAMESPACE

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  • C#/.NET Little Wonders: The ConcurrentDictionary

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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  • on coding style

    - by user12607414
    I vastly prefer coding to discussing coding style, just as I would prefer to write poetry instead of talking about how it should be written. Sometimes the topic cannot be put off, either because some individual coder is messing up a shared code base and needs to be corrected, or (worse) because some officious soul has decided, "what we really need around here are some strongly enforced style rules!" Neither is the case at the moment, and yet I will venture a post on the subject. The following are not rules, but suggested etiquette. The idea is to allow a coherent style of coding to flourish safely and sanely, as a humane, inductive, social process. Maxim M1: Observe, respect, and imitate the largest-scale precedents available. (Preserve styles of whitespace, capitalization, punctuation, abbreviation, name choice, code block size, factorization, type of comments, class organization, file naming, etc., etc., etc.) Maxim M2: Don't add weight to small-scale variations. (Realize that Maxim M1 has been broken many times, but don't take that as license to create further irregularities.) Maxim M3: Listen to and rely on your reviewers to help you perceive your own coding quirks. (When you review, help the coder do this.) Maxim M4: When you touch some code, try to leave it more readable than you found it. (When you review such changes, thank the coder for the cleanup. When you plan changes, plan for cleanups.) On the Hotspot project, which is almost 1.5 decades old, we have often practiced and benefited from such etiquette. The process is, and should be, inductive, not prescriptive. An ounce of neighborliness is better than a pound of police-work. Reality check: If you actually look at (or live in) the Hotspot code base, you will find we have accumulated many annoying irregularities in our source base. I suppose this is the normal condition of a lived-in space. Unless you want to spend all your time polishing and tidying, you can't live without some smudge and clutter, can you? Final digression: Grammars and dictionaries and other prescriptive rule books are sometimes useful, but we humans learn and maintain our language by example not grammar. The same applies to style rules. Actually, I think the process of maintaining a clean and pleasant working code base is an instance of a community maintaining its common linguistic identity. BTW, I've been reading and listening to John McWhorter lately with great pleasure. (If you end with a digression, is it a tail-digression?)

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  • Developing custom MBeans to manage J2EE Applications (Part III)

    - by philippe Le Mouel
    This is the third and final part in a series of blogs, that demonstrate how to add management capability to your own application using JMX MBeans. In Part I we saw: How to implement a custom MBean to manage configuration associated with an application. How to package the resulting code and configuration as part of the application's ear file. How to register MBeans upon application startup, and unregistered them upon application stop (or undeployment). How to use generic JMX clients such as JConsole to browse and edit our application's MBean. In Part II we saw: How to add localized descriptions to our MBean, MBean attributes, MBean operations and MBean operation parameters. How to specify meaningful name to our MBean operation parameters. We also touched on future enhancements that will simplify how we can implement localized MBeans. In this third and last part, we will re-write our MBean to simplify how we added localized descriptions. To do so we will take advantage of the functionality we already described in part II and that is now part of WebLogic 10.3.3.0. We will show how to take advantage of WebLogic's localization support to localize our MBeans based on the client's Locale independently of the server's Locale. Each client will see MBean descriptions localized based on his/her own Locale. We will show how to achieve this using JConsole, and also using a sample programmatic JMX Java client. The complete code sample and associated build files for part III are available as a zip file. The code has been tested against WebLogic Server 10.3.3.0 and JDK6. To build and deploy our sample application, please follow the instruction provided in Part I, as they also apply to part III's code and associated zip file. Providing custom descriptions take II In part II we localized our MBean descriptions by extending the StandardMBean class and overriding its many getDescription methods. WebLogic 10.3.3.0 similarly to JDK 7 can automatically localize MBean descriptions as long as those are specified according to the following conventions: Descriptions resource bundle keys are named according to: MBean description: <MBeanInterfaceClass>.mbean MBean attribute description: <MBeanInterfaceClass>.attribute.<AttributeName> MBean operation description: <MBeanInterfaceClass>.operation.<OperationName> MBean operation parameter description: <MBeanInterfaceClass>.operation.<OperationName>.<ParameterName> MBean constructor description: <MBeanInterfaceClass>.constructor.<ConstructorName> MBean constructor parameter description: <MBeanInterfaceClass>.constructor.<ConstructorName>.<ParameterName> We also purposely named our resource bundle class MBeanDescriptions and included it as part of the same package as our MBean. We already followed the above conventions when creating our resource bundle in part II, and our default resource bundle class with English descriptions looks like: package blog.wls.jmx.appmbean; import java.util.ListResourceBundle; public class MBeanDescriptions extends ListResourceBundle { protected Object[][] getContents() { return new Object[][] { {"PropertyConfigMXBean.mbean", "MBean used to manage persistent application properties"}, {"PropertyConfigMXBean.attribute.Properties", "Properties associated with the running application"}, {"PropertyConfigMXBean.operation.setProperty", "Create a new property, or change the value of an existing property"}, {"PropertyConfigMXBean.operation.setProperty.key", "Name that identify the property to set."}, {"PropertyConfigMXBean.operation.setProperty.value", "Value for the property being set"}, {"PropertyConfigMXBean.operation.getProperty", "Get the value for an existing property"}, {"PropertyConfigMXBean.operation.getProperty.key", "Name that identify the property to be retrieved"} }; } } We have now also added a resource bundle with French localized descriptions: package blog.wls.jmx.appmbean; import java.util.ListResourceBundle; public class MBeanDescriptions_fr extends ListResourceBundle { protected Object[][] getContents() { return new Object[][] { {"PropertyConfigMXBean.mbean", "Manage proprietes sauvegarde dans un fichier disque."}, {"PropertyConfigMXBean.attribute.Properties", "Proprietes associee avec l'application en cour d'execution"}, {"PropertyConfigMXBean.operation.setProperty", "Construit une nouvelle proprietee, ou change la valeur d'une proprietee existante."}, {"PropertyConfigMXBean.operation.setProperty.key", "Nom de la propriete dont la valeur est change."}, {"PropertyConfigMXBean.operation.setProperty.value", "Nouvelle valeur"}, {"PropertyConfigMXBean.operation.getProperty", "Retourne la valeur d'une propriete existante."}, {"PropertyConfigMXBean.operation.getProperty.key", "Nom de la propriete a retrouver."} }; } } So now we can just remove the many getDescriptions methods from our MBean code, and have a much cleaner: package blog.wls.jmx.appmbean; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.File; import java.net.URL; import java.util.Map; import java.util.HashMap; import java.util.Properties; import javax.management.MBeanServer; import javax.management.ObjectName; import javax.management.MBeanRegistration; import javax.management.StandardMBean; import javax.management.MBeanOperationInfo; import javax.management.MBeanParameterInfo; public class PropertyConfig extends StandardMBean implements PropertyConfigMXBean, MBeanRegistration { private String relativePath_ = null; private Properties props_ = null; private File resource_ = null; private static Map operationsParamNames_ = null; static { operationsParamNames_ = new HashMap(); operationsParamNames_.put("setProperty", new String[] {"key", "value"}); operationsParamNames_.put("getProperty", new String[] {"key"}); } public PropertyConfig(String relativePath) throws Exception { super(PropertyConfigMXBean.class , true); props_ = new Properties(); relativePath_ = relativePath; } public String setProperty(String key, String value) throws IOException { String oldValue = null; if (value == null) { oldValue = String.class.cast(props_.remove(key)); } else { oldValue = String.class.cast(props_.setProperty(key, value)); } save(); return oldValue; } public String getProperty(String key) { return props_.getProperty(key); } public Map getProperties() { return (Map) props_; } private void load() throws IOException { InputStream is = new FileInputStream(resource_); try { props_.load(is); } finally { is.close(); } } private void save() throws IOException { OutputStream os = new FileOutputStream(resource_); try { props_.store(os, null); } finally { os.close(); } } public ObjectName preRegister(MBeanServer server, ObjectName name) throws Exception { // MBean must be registered from an application thread // to have access to the application ClassLoader ClassLoader cl = Thread.currentThread().getContextClassLoader(); URL resourceUrl = cl.getResource(relativePath_); resource_ = new File(resourceUrl.toURI()); load(); return name; } public void postRegister(Boolean registrationDone) { } public void preDeregister() throws Exception {} public void postDeregister() {} protected String getParameterName(MBeanOperationInfo op, MBeanParameterInfo param, int sequence) { return operationsParamNames_.get(op.getName())[sequence]; } } The only reason we are still extending the StandardMBean class, is to override the default values for our operations parameters name. If this isn't a concern, then one could just write the following code: package blog.wls.jmx.appmbean; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.File; import java.net.URL; import java.util.Properties; import javax.management.MBeanServer; import javax.management.ObjectName; import javax.management.MBeanRegistration; import javax.management.StandardMBean; import javax.management.MBeanOperationInfo; import javax.management.MBeanParameterInfo; public class PropertyConfig implements PropertyConfigMXBean, MBeanRegistration { private String relativePath_ = null; private Properties props_ = null; private File resource_ = null; public PropertyConfig(String relativePath) throws Exception { props_ = new Properties(); relativePath_ = relativePath; } public String setProperty(String key, String value) throws IOException { String oldValue = null; if (value == null) { oldValue = String.class.cast(props_.remove(key)); } else { oldValue = String.class.cast(props_.setProperty(key, value)); } save(); return oldValue; } public String getProperty(String key) { return props_.getProperty(key); } public Map getProperties() { return (Map) props_; } private void load() throws IOException { InputStream is = new FileInputStream(resource_); try { props_.load(is); } finally { is.close(); } } private void save() throws IOException { OutputStream os = new FileOutputStream(resource_); try { props_.store(os, null); } finally { os.close(); } } public ObjectName preRegister(MBeanServer server, ObjectName name) throws Exception { // MBean must be registered from an application thread // to have access to the application ClassLoader ClassLoader cl = Thread.currentThread().getContextClassLoader(); URL resourceUrl = cl.getResource(relativePath_); resource_ = new File(resourceUrl.toURI()); load(); return name; } public void postRegister(Boolean registrationDone) { } public void preDeregister() throws Exception {} public void postDeregister() {} } Note: The above would also require changing the operations parameters name in the resource bundle classes. For instance: PropertyConfigMXBean.operation.setProperty.key would become: PropertyConfigMXBean.operation.setProperty.p0 Client based localization When accessing our MBean using JConsole started with the following command line: jconsole -J-Djava.class.path=$JAVA_HOME/lib/jconsole.jar:$JAVA_HOME/lib/tools.jar: $WL_HOME/server/lib/wljmxclient.jar -J-Djmx.remote.protocol.provider.pkgs=weblogic.management.remote -debug We see that our MBean descriptions are localized according to the WebLogic's server Locale. English in this case: Note: Consult Part I for information on how to use JConsole to browse/edit our MBean. Now if we specify the client's Locale as part of the JConsole command line as follow: jconsole -J-Djava.class.path=$JAVA_HOME/lib/jconsole.jar:$JAVA_HOME/lib/tools.jar: $WL_HOME/server/lib/wljmxclient.jar -J-Djmx.remote.protocol.provider.pkgs=weblogic.management.remote -J-Dweblogic.management.remote.locale=fr-FR -debug We see that our MBean descriptions are now localized according to the specified client's Locale. French in this case: We use the weblogic.management.remote.locale system property to specify the Locale that should be associated with the cient's JMX connections. The value is composed of the client's language code and its country code separated by the - character. The country code is not required, and can be omitted. For instance: -Dweblogic.management.remote.locale=fr We can also specify the client's Locale using a programmatic client as demonstrated below: package blog.wls.jmx.appmbean.client; import javax.management.MBeanServerConnection; import javax.management.ObjectName; import javax.management.MBeanInfo; import javax.management.remote.JMXConnector; import javax.management.remote.JMXServiceURL; import javax.management.remote.JMXConnectorFactory; import java.util.Hashtable; import java.util.Set; import java.util.Locale; public class JMXClient { public static void main(String[] args) throws Exception { JMXConnector jmxCon = null; try { JMXServiceURL serviceUrl = new JMXServiceURL( "service:jmx:iiop://127.0.0.1:7001/jndi/weblogic.management.mbeanservers.runtime"); System.out.println("Connecting to: " + serviceUrl); // properties associated with the connection Hashtable env = new Hashtable(); env.put(JMXConnectorFactory.PROTOCOL_PROVIDER_PACKAGES, "weblogic.management.remote"); String[] credentials = new String[2]; credentials[0] = "weblogic"; credentials[1] = "weblogic"; env.put(JMXConnector.CREDENTIALS, credentials); // specifies the client's Locale env.put("weblogic.management.remote.locale", Locale.FRENCH); jmxCon = JMXConnectorFactory.newJMXConnector(serviceUrl, env); jmxCon.connect(); MBeanServerConnection con = jmxCon.getMBeanServerConnection(); Set mbeans = con.queryNames( new ObjectName( "blog.wls.jmx.appmbean:name=myAppProperties,type=PropertyConfig,*"), null); for (ObjectName mbeanName : mbeans) { System.out.println("\n\nMBEAN: " + mbeanName); MBeanInfo minfo = con.getMBeanInfo(mbeanName); System.out.println("MBean Description: "+minfo.getDescription()); System.out.println("\n"); } } finally { // release the connection if (jmxCon != null) jmxCon.close(); } } } The above client code is part of the zip file associated with this blog, and can be run using the provided client.sh script. The resulting output is shown below: $ ./client.sh Connecting to: service:jmx:iiop://127.0.0.1:7001/jndi/weblogic.management.mbeanservers.runtime MBEAN: blog.wls.jmx.appmbean:type=PropertyConfig,name=myAppProperties MBean Description: Manage proprietes sauvegarde dans un fichier disque. $ Miscellaneous Using Description annotation to specify MBean descriptions Earlier we have seen how to name our MBean descriptions resource keys, so that WebLogic 10.3.3.0 automatically uses them to localize our MBean. In some cases we might want to implicitly specify the resource key, and resource bundle. For instance when operations are overloaded, and the operation name is no longer sufficient to uniquely identify a single operation. In this case we can use the Description annotation provided by WebLogic as follow: import weblogic.management.utils.Description; @Description(resourceKey="myapp.resources.TestMXBean.description", resourceBundleBaseName="myapp.resources.MBeanResources") public interface TestMXBean { @Description(resourceKey="myapp.resources.TestMXBean.threshold.description", resourceBundleBaseName="myapp.resources.MBeanResources" ) public int getthreshold(); @Description(resourceKey="myapp.resources.TestMXBean.reset.description", resourceBundleBaseName="myapp.resources.MBeanResources") public int reset( @Description(resourceKey="myapp.resources.TestMXBean.reset.id.description", resourceBundleBaseName="myapp.resources.MBeanResources", displayNameKey= "myapp.resources.TestMXBean.reset.id.displayName.description") int id); } The Description annotation should be applied to the MBean interface. It can be used to specify MBean, MBean attributes, MBean operations, and MBean operation parameters descriptions as demonstrated above. Retrieving the Locale associated with a JMX operation from the MBean code There are several cases where it is necessary to retrieve the Locale associated with a JMX call from the MBean implementation. For instance this can be useful when localizing exception messages. This can be done as follow: import weblogic.management.mbeanservers.JMXContextUtil; ...... // some MBean method implementation public String setProperty(String key, String value) throws IOException { Locale callersLocale = JMXContextUtil.getLocale(); // use callersLocale to localize Exception messages or // potentially some return values such a Date .... } Conclusion With this last part we conclude our three part series on how to write MBeans to manage J2EE applications. We are far from having exhausted this particular topic, but we have gone a long way and are now capable to take advantage of the latest functionality provided by WebLogic's application server to write user friendly MBeans.

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  • Taking the fear out of a Cloud initiative through the use of security tools

    - by user736511
    Typical employees, constituents, and business owners  interact with online services at a level where their knowledge of back-end systems is low, and most of the times, there is no interest in knowing the systems' architecture.  Most application administrators, while partially responsible for these systems' upkeep, have very low interactions with them, at least at an operational, platform level.  Of greatest interest to these groups is the consistent, reliable, and manageable operation of the interfaces with which they communicate.  Introducing the "Cloud" topic in any evolving architecture automatically raises the concerns for data and identity security simply because of the perception that when owning the silicon, enterprises are not able to manage its content.  But is this really true?   In the majority of traditional architectures, data and applications that access it are physically distant from the organization that owns it.  It may reside in a shared data center, or a geographically convenient location that spans large organizations' connectivity capabilities.  In the end, very often, the model of a "traditional" architecture is fairly close to the "new" Cloud architecture.  Most notable difference is that by nature, a Cloud setup uses security as a core function, and not as a necessary add-on. Therefore, following best practices, one can say that data can be safer in the Cloud than in traditional, stove-piped environments where data access is segmented and difficult to audit. The caveat is, of course, what "best practices" consist of, and here is where Oracle's security tools are perfectly suited for the task.  Since Oracle's model is to support very large organizations, it is fundamentally concerned about distributed applications, databases etc and their security, and the related Identity Management Products, or DB Security options reflect that concept.  In the end, consumers of applications and their data are to be served more safely in a controlled Cloud environment, while realizing the many cost savings associated with it. Having very fast resources to serve them (such as the Exa* platform) makes the concept even more attractive.  Finally, if a Cloud strategy does not seem feasible, consider the pros and cons of a traditional vs. a Cloud architecture.  Using the exact same criteria and business goals/traditions, and with Oracle's technology, you might be hard pressed to justify maintaining the technical status quo on security alone. For additional information please visit Oracle's Cloud Security page at: http://www.oracle.com/us/technologies/cloud/cloud-security-428855.html

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  • How to repair an external harddrive?

    - by dodohjk
    I would like to reformat my hard disk, and if possible recover the (somewhat unimportant) contents if possible. I have a Western Digital 1TB hard drive which had a NTFS partition. I unplugged the drive without safely removing it first. At first a pop up was asking me to use a Windows OS to run the chkdsk /f command, however, in the effort to keep using a Linux OS I used the ntfsfix command on the ubuntu terminal Now, when I try to access the hard drive, it doesn't show up anymore in Nautilus. I tried reformatting it using Disk Utility, but it gives me an error message, and Gparted would hang on the "Scanning devices" step infinitely. Please comment any output that you would like to see and I will add it to my question. EDIT disk utility tells me is on /dev/sdb the command sudo fdisk -l gives dodohjk@DodosPC:~$ sudo fdisk -l [sudo] password for dodohjk: Disk /dev/sda: 250.1 GB, 250059350016 bytes 255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0006fa8c Device Boot Start End Blocks Id System /dev/sda1 * 4094 482344959 241170433 5 Extended /dev/sda2 482344960 488396799 3025920 82 Linux swap / Solaris /dev/sda5 4096 31461127 15728516 83 Linux /dev/sda6 31463424 52434943 10485760 83 Linux /dev/sda7 52436992 62923320 5243164+ 83 Linux /dev/sda8 62924800 482344959 209710080 83 Linux Disk /dev/sdb: 1000.2 GB, 1000202043392 bytes 255 heads, 63 sectors/track, 121600 cylinders, total 1953519616 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x6e697373 This doesn't look like a partition table Probably you selected the wrong device. Device Boot Start End Blocks Id System /dev/sdb1 ? 1936269394 3772285809 918008208 4f QNX4.x 3rd part /dev/sdb2 ? 1917848077 2462285169 272218546+ 73 Unknown /dev/sdb3 ? 1818575915 2362751050 272087568 2b Unknown /dev/sdb4 ? 2844524554 2844579527 27487 61 SpeedStor Partition table entries are not in disk order I wrote something wrong here, however here the output of fsck /dev/sbd is dodohjk@DodosPC:~$ sudo fsck /dev/sdb fsck from util-linux 2.20.1 e2fsck 1.42.5 (29-Jul-2012) ext2fs_open2: Bad magic number in super-block fsck.ext2: Superblock invalid, trying backup blocks... fsck.ext2: Bad magic number in super-block while trying to open /dev/sdb The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsck -b 8193 <device&gt;

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  • Partner Webcast – More out of ODA with DB Options - 19 July 2012

    - by Thanos
    The Simple, Reliable, Affordable Path to High-Availability Databases Critical business data needs to be available 24/7 for users and customers, but it can be a struggle to find the time and resources to build a highly available database system that’s reliable and affordable. That’s why Oracle created the new Oracle Database Appliance—a complete package of software, server, storage, and networking. The Oracle Database Appliance integrates the world’s most popular database - Oracle Database 11g  - with system software, servers, storage and networking in a single box. Business gets the benefit of a reliable, secure and highly available database to support applications and maintain continuity – as well as groundbreaking ease of use. But that is not all, with the support for all Oracle Database Options, Oracle Database Appliance can be the ideal solution for many use cases. The benefits?   Unmatched performance, reliability & security for your data that’s there when you need it – which is all the time. Fast installation, simple deployment, easy management. Out of the box. Significant cost savings & reduced risk and complexity compared to integrating all the elements yourself. Ongoing lower total cost of ownership with multiple automated support, detection & correction functions that also save you time.   Discover the Oracle Database Appliance Value Proposition and learn how to position and combine it with database options to capture new business and easily roll out solutions safely and with maximum cost efficiency. Agenda: Oracle Database& Engineered Systems Innovation. What’s the Oracle Database Appliance ? Oracle Database Appliance Value Proposition. Oracle Database Appliance with Database Options Oracle Database Appliance Partners Business Delivery Format This FREE online LIVE eSeminar will be delivered over the Web. Registrations received less than 24hours prior to start time may not receive confirmation to attend. Duration: 1 hour Register Now! For any questions please contact us at partner.imc-AT-beehiveonline.oracle-DOT-com Visit regularly our ISV Migration Center blog Or Follow us @oracleimc to learn more on Oracle Technologies as well as upcoming partner webcasts and events.

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  • C#/.NET Little Wonders: The Useful But Overlooked Sets

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  Today we will be looking at two set implementations in the System.Collections.Generic namespace: HashSet<T> and SortedSet<T>.  Even though most people think of sets as mathematical constructs, they are actually very useful classes that can be used to help make your application more performant if used appropriately. A Background From Math In mathematical terms, a set is an unordered collection of unique items.  In other words, the set {2,3,5} is identical to the set {3,5,2}.  In addition, the set {2, 2, 4, 1} would be invalid because it would have a duplicate item (2).  In addition, you can perform set arithmetic on sets such as: Intersections: The intersection of two sets is the collection of elements common to both.  Example: The intersection of {1,2,5} and {2,4,9} is the set {2}. Unions: The union of two sets is the collection of unique items present in either or both set.  Example: The union of {1,2,5} and {2,4,9} is {1,2,4,5,9}. Differences: The difference of two sets is the removal of all items from the first set that are common between the sets.  Example: The difference of {1,2,5} and {2,4,9} is {1,5}. Supersets: One set is a superset of a second set if it contains all elements that are in the second set. Example: The set {1,2,5} is a superset of {1,5}. Subsets: One set is a subset of a second set if all the elements of that set are contained in the first set. Example: The set {1,5} is a subset of {1,2,5}. If We’re Not Doing Math, Why Do We Care? Now, you may be thinking: why bother with the set classes in C# if you have no need for mathematical set manipulation?  The answer is simple: they are extremely efficient ways to determine ownership in a collection. For example, let’s say you are designing an order system that tracks the price of a particular equity, and once it reaches a certain point will trigger an order.  Now, since there’s tens of thousands of equities on the markets, you don’t want to track market data for every ticker as that would be a waste of time and processing power for symbols you don’t have orders for.  Thus, we just want to subscribe to the stock symbol for an equity order only if it is a symbol we are not already subscribed to. Every time a new order comes in, we will check the list of subscriptions to see if the new order’s stock symbol is in that list.  If it is, great, we already have that market data feed!  If not, then and only then should we subscribe to the feed for that symbol. So far so good, we have a collection of symbols and we want to see if a symbol is present in that collection and if not, add it.  This really is the essence of set processing, but for the sake of comparison, let’s say you do a list instead: 1: // class that handles are order processing service 2: public sealed class OrderProcessor 3: { 4: // contains list of all symbols we are currently subscribed to 5: private readonly List<string> _subscriptions = new List<string>(); 6:  7: ... 8: } Now whenever you are adding a new order, it would look something like: 1: public PlaceOrderResponse PlaceOrder(Order newOrder) 2: { 3: // do some validation, of course... 4:  5: // check to see if already subscribed, if not add a subscription 6: if (!_subscriptions.Contains(newOrder.Symbol)) 7: { 8: // add the symbol to the list 9: _subscriptions.Add(newOrder.Symbol); 10: 11: // do whatever magic is needed to start a subscription for the symbol 12: } 13:  14: // place the order logic! 15: } What’s wrong with this?  In short: performance!  Finding an item inside a List<T> is a linear - O(n) – operation, which is not a very performant way to find if an item exists in a collection. (I used to teach algorithms and data structures in my spare time at a local university, and when you began talking about big-O notation you could immediately begin to see eyes glossing over as if it was pure, useless theory that would not apply in the real world, but I did and still do believe it is something worth understanding well to make the best choices in computer science). Let’s think about this: a linear operation means that as the number of items increases, the time that it takes to perform the operation tends to increase in a linear fashion.  Put crudely, this means if you double the collection size, you might expect the operation to take something like the order of twice as long.  Linear operations tend to be bad for performance because they mean that to perform some operation on a collection, you must potentially “visit” every item in the collection.  Consider finding an item in a List<T>: if you want to see if the list has an item, you must potentially check every item in the list before you find it or determine it’s not found. Now, we could of course sort our list and then perform a binary search on it, but sorting is typically a linear-logarithmic complexity – O(n * log n) - and could involve temporary storage.  So performing a sort after each add would probably add more time.  As an alternative, we could use a SortedList<TKey, TValue> which sorts the list on every Add(), but this has a similar level of complexity to move the items and also requires a key and value, and in our case the key is the value. This is why sets tend to be the best choice for this type of processing: they don’t rely on separate keys and values for ordering – so they save space – and they typically don’t care about ordering – so they tend to be extremely performant.  The .NET BCL (Base Class Library) has had the HashSet<T> since .NET 3.5, but at that time it did not implement the ISet<T> interface.  As of .NET 4.0, HashSet<T> implements ISet<T> and a new set, the SortedSet<T> was added that gives you a set with ordering. HashSet<T> – For Unordered Storage of Sets When used right, HashSet<T> is a beautiful collection, you can think of it as a simplified Dictionary<T,T>.  That is, a Dictionary where the TKey and TValue refer to the same object.  This is really an oversimplification, but logically it makes sense.  I’ve actually seen people code a Dictionary<T,T> where they store the same thing in the key and the value, and that’s just inefficient because of the extra storage to hold both the key and the value. As it’s name implies, the HashSet<T> uses a hashing algorithm to find the items in the set, which means it does take up some additional space, but it has lightning fast lookups!  Compare the times below between HashSet<T> and List<T>: Operation HashSet<T> List<T> Add() O(1) O(1) at end O(n) in middle Remove() O(1) O(n) Contains() O(1) O(n)   Now, these times are amortized and represent the typical case.  In the very worst case, the operations could be linear if they involve a resizing of the collection – but this is true for both the List and HashSet so that’s a less of an issue when comparing the two. The key thing to note is that in the general case, HashSet is constant time for adds, removes, and contains!  This means that no matter how large the collection is, it takes roughly the exact same amount of time to find an item or determine if it’s not in the collection.  Compare this to the List where almost any add or remove must rearrange potentially all the elements!  And to find an item in the list (if unsorted) you must search every item in the List. So as you can see, if you want to create an unordered collection and have very fast lookup and manipulation, the HashSet is a great collection. And since HashSet<T> implements ICollection<T> and IEnumerable<T>, it supports nearly all the same basic operations as the List<T> and can use the System.Linq extension methods as well. All we have to do to switch from a List<T> to a HashSet<T>  is change our declaration.  Since List and HashSet support many of the same members, chances are we won’t need to change much else. 1: public sealed class OrderProcessor 2: { 3: private readonly HashSet<string> _subscriptions = new HashSet<string>(); 4:  5: // ... 6:  7: public PlaceOrderResponse PlaceOrder(Order newOrder) 8: { 9: // do some validation, of course... 10: 11: // check to see if already subscribed, if not add a subscription 12: if (!_subscriptions.Contains(newOrder.Symbol)) 13: { 14: // add the symbol to the list 15: _subscriptions.Add(newOrder.Symbol); 16: 17: // do whatever magic is needed to start a subscription for the symbol 18: } 19: 20: // place the order logic! 21: } 22:  23: // ... 24: } 25: Notice, we didn’t change any code other than the declaration for _subscriptions to be a HashSet<T>.  Thus, we can pick up the performance improvements in this case with minimal code changes. SortedSet<T> – Ordered Storage of Sets Just like HashSet<T> is logically similar to Dictionary<T,T>, the SortedSet<T> is logically similar to the SortedDictionary<T,T>. The SortedSet can be used when you want to do set operations on a collection, but you want to maintain that collection in sorted order.  Now, this is not necessarily mathematically relevant, but if your collection needs do include order, this is the set to use. So the SortedSet seems to be implemented as a binary tree (possibly a red-black tree) internally.  Since binary trees are dynamic structures and non-contiguous (unlike List and SortedList) this means that inserts and deletes do not involve rearranging elements, or changing the linking of the nodes.  There is some overhead in keeping the nodes in order, but it is much smaller than a contiguous storage collection like a List<T>.  Let’s compare the three: Operation HashSet<T> SortedSet<T> List<T> Add() O(1) O(log n) O(1) at end O(n) in middle Remove() O(1) O(log n) O(n) Contains() O(1) O(log n) O(n)   The MSDN documentation seems to indicate that operations on SortedSet are O(1), but this seems to be inconsistent with its implementation and seems to be a documentation error.  There’s actually a separate MSDN document (here) on SortedSet that indicates that it is, in fact, logarithmic in complexity.  Let’s put it in layman’s terms: logarithmic means you can double the collection size and typically you only add a single extra “visit” to an item in the collection.  Take that in contrast to List<T>’s linear operation where if you double the size of the collection you double the “visits” to items in the collection.  This is very good performance!  It’s still not as performant as HashSet<T> where it always just visits one item (amortized), but for the addition of sorting this is a good thing. Consider the following table, now this is just illustrative data of the relative complexities, but it’s enough to get the point: Collection Size O(1) Visits O(log n) Visits O(n) Visits 1 1 1 1 10 1 4 10 100 1 7 100 1000 1 10 1000   Notice that the logarithmic – O(log n) – visit count goes up very slowly compare to the linear – O(n) – visit count.  This is because since the list is sorted, it can do one check in the middle of the list, determine which half of the collection the data is in, and discard the other half (binary search).  So, if you need your set to be sorted, you can use the SortedSet<T> just like the HashSet<T> and gain sorting for a small performance hit, but it’s still faster than a List<T>. Unique Set Operations Now, if you do want to perform more set-like operations, both implementations of ISet<T> support the following, which play back towards the mathematical set operations described before: IntersectWith() – Performs the set intersection of two sets.  Modifies the current set so that it only contains elements also in the second set. UnionWith() – Performs a set union of two sets.  Modifies the current set so it contains all elements present both in the current set and the second set. ExceptWith() – Performs a set difference of two sets.  Modifies the current set so that it removes all elements present in the second set. IsSupersetOf() – Checks if the current set is a superset of the second set. IsSubsetOf() – Checks if the current set is a subset of the second set. For more information on the set operations themselves, see the MSDN description of ISet<T> (here). What Sets Don’t Do Don’t get me wrong, sets are not silver bullets.  You don’t really want to use a set when you want separate key to value lookups, that’s what the IDictionary implementations are best for. Also sets don’t store temporal add-order.  That is, if you are adding items to the end of a list all the time, your list is ordered in terms of when items were added to it.  This is something the sets don’t do naturally (though you could use a SortedSet with an IComparer with a DateTime but that’s overkill) but List<T> can. Also, List<T> allows indexing which is a blazingly fast way to iterate through items in the collection.  Iterating over all the items in a List<T> is generally much, much faster than iterating over a set. Summary Sets are an excellent tool for maintaining a lookup table where the item is both the key and the value.  In addition, if you have need for the mathematical set operations, the C# sets support those as well.  The HashSet<T> is the set of choice if you want the fastest possible lookups but don’t care about order.  In contrast the SortedSet<T> will give you a sorted collection at a slight reduction in performance.   Technorati Tags: C#,.Net,Little Wonders,BlackRabbitCoder,ISet,HashSet,SortedSet

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