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  • Experiences with D-programming-language

    - by Dario
    Has someone here ever had experience with the D programming language? It seems to have many nice features but will it ever reach the popularity of those currently widespread languages like C++, Java or C#? So is it worth learning or is it an isolated language with minor prospects.

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  • Why a thread is aborted in ASP.NET MVC (again)?

    - by Dario Solera
    Here is what I do in a controller action: create and start a new Thread that does a relatively long processing task (~30 seconds on average, but might be several minutes) immediately return the page response so the user knows processing has started (trivially, a Json with a task ID for polling purposes). At some random point, ThreadAbortException is thrown, so the async task does not complete. The exception is not thrown every time, it just happens randomly roughly 25% of the times. Points to note: I'm not calling Response.End or Response.Redirect - there isn't even a request running when the exception is thrown I tried using ThreadPool and I got the same behavior I know running threads in ASP.NET has several caveats but I don't care right now Any suggestion?

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  • Lightweight version control software on Linux

    - by I'm Dario
    I'm working with a shell account in a shared system and I would like to use some version control software for my bash scripts and config files. It must works on Linux with no dependencies, just unpack it in my home dir. I don't need remote checkout, branching or other fancy tricks. I want to be able to commit my changes and restore them if needed.

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  • Picture changing in vb6

    - by Dario Dias
    I was trying this script from a pdf file.I got stuck where the target image should change to exploding image if clicked but the target image does not change from the standing image.Please Help! Option Explicit Dim fiPlayersScore As Integer Dim fiNumberofMisses As Integer Dim fbTargetHit As Boolean Private Sub Form_Load() Randomize imgTarget.Enabled = False imgTarget.Visible = False cmdStop.Enabled = False lblGameOver.Visible = False lblGameOver.Enabled = False End Sub Private Sub cmdStart_Click() Dim lsUserResponse As String Dim lbResponse As Boolean lsUserResponse = InputBox("Enter a level from 1 to 3." & _ (Chr(13)) & "" & (Chr(13)) & "1 being the Easiest and 3 being the " & _ "Hardest.", "Level Select", "1") lbResponse = False If lsUserResponse = "1" Then Timer1.Interval = 1500 lbResponse = True ElseIf lsUserResponse = "2" Then Timer1.Interval = 1000 lbResponse = True ElseIf lsUserResponse = "3" Then Timer1.Interval = 750 lbResponse = True Else MsgBox ("Game Not Started.") lbResponse = False End If If lbResponse = True Then cmdStart.Enabled = False imgTarget.Picture = imgStanding.Picture frmMain.MousePointer = 5 fbTargetHit = False Load_Sounds cmdStop.Enabled = True fiPlayersScore = 0 fiNumberofMisses = 0 lblScore.Caption = fiPlayersScore lblMisses.Caption = fiNumberofMisses Timer1.Enabled = True lblGameOver.Visible = False lblGameOver.Enabled = False End If End Sub Private Sub cmdStop_Click() Unload_Sounds frmMain.MousePointer = vbNormal Timer1.Enabled = False imgTarget.Enabled = False imgTarget.Visible = False cmdStart.Enabled = True cmdStop.Enabled = False cmdStart.SetFocus lblGameOver.Visible = True lblGameOver.Enabled = True End Sub Private Sub Form_Click() MMControl1.Command = "Play" MMControl1.Command = "Prev" fiNumberofMisses = fiNumberofMisses + 1 lblMisses.Caption = fiNumberofMisses If CheckForLoose = True Then cmdStop_Click lblMisses.Caption = fiNumberofMisses Exit Sub End If End Sub Private Sub imgTarget_Click() MMControl2.Command = "Play" MMControl2.Command = "Prev" Timer1.Enabled = False imgTarget.Picture = imgExplode.Picture '**I AM STUCK HERE** pauseProgram fiPlayersScore = fiPlayersScore + 1 Timer1.Enabled = True If CheckForWin = True Then cmdStop_Click lblScore.Caption = fiPlayersScore Exit Sub End If lblScore.Caption = fiPlayersScore fbTargetHit = True imgStanding.Enabled = False imgTarget.Visible = False imgTarget.Enabled = False Timer1.Enabled = True End Sub Public Sub Load_Sounds() 'Set initial property values for blaster sound MMControl1.Notify = False MMControl1.Wait = True MMControl1.Shareable = False MMControl1.DeviceType = "WaveAudio" MMControl1.FileName = _ "C:\Temp\Sounds\Blaster_1.wav" 'Open the media device MMControl1.Command = "Open" 'Set initial property values for grunt sound MMControl2.Notify = False MMControl2.Wait = True MMControl2.Shareable = False MMControl2.DeviceType = "WaveAudio" MMControl2.FileName = _ "C:\Temp\Sounds\Pain_Grunt_4.wav" 'Open the media device MMControl2.Command = "Open" End Sub Private Sub Timer1_Timer() Dim liRandomLeft As Integer Dim liRandomTop As Integer imgTarget.Visible = True If fbTargetHit = True Then fbTargetHit = False 'imgTarget.Picture = imgStanding.Picture End If liRandomLeft = (6120 * Rnd) liRandomTop = (4680 * Rnd) imgTarget.Left = liRandomLeft imgTarget.Top = liRandomTop imgTarget.Enabled = True imgTarget.Visible = True End Sub Public Function CheckForWin() As Boolean CheckForWin = False If fiPlayersScore = 5 Then CheckForWin = True lblGameOver.Caption = "You Win.Game Over" End If End Function Public Function CheckForLoose() As Boolean CheckForLoose = False If fiNumberofMisses = 5 Then CheckForLoose = True lblGameOver.Caption = "You Loose.Game Over" End If End Function Private Sub Form_QueryUnload(Cancel As Integer, _ UnloadMode As Integer) Unload_Sounds End Sub Public Sub Unload_Sounds() MMControl1.Command = "Close" MMControl2.Command = "Close" End Sub Public Sub pauseProgram() Dim currentTime Dim newTime currentTime = Second(Time) newTime = Second(Time) Do Until Abs(newTime - currentTime) = 1 newTime = Second(Time) Loop End Sub

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  • How to map inheritance with property returned other inheritance?

    - by dario-g
    Hi I have abstract class Vehicle and two classes that derive from: Car and ForkLift. public abstract class Vehicle { public EngineBase Engine { get; set; } } public class Car : Vehicle { public GasEngine Engine { get; set; } } public class ForkLift : Vehicle { public ElectricEngine Engine { get; set; } } and Engine clasess: public abstract class Engine { } public class GasEngine : Engine { } public class ElectricEngine : Engine { } Engines are mapped with "table per class hierarchy". With Vehicles I want to use the same pattern. How to map Engine class and derived with that Engine property?

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  • How to write this in better way?

    - by dario
    Hi all. Let's look at this code: IList<IHouseAnnouncement> list = new List<IHouseAnnouncement>(); var table = adapter.GetData(); //get data from repository object -> DataTable if (table.Rows.Count >= 1) { for (int i = 0; i < table.Rows.Count-1; i++) { var anno = new HouseAnnouncement(); anno.Area = float.Parse(table.Rows[i][table.powierzchniaColumn].ToString()); anno.City = table.Rows[i][table.miastoColumn].ToString(); list.Add(anno); } } return list; Is it better way to write this in less code and better fashion (must be :-) )? Maybe using labda (but let mi know how)? Thanks in advance!

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  • timing response speed of serial device

    - by dario frongi
    I comunicate with a serial device via bluetooth. i send it pid and it responds to me with a data response. i comunicate with him with serial comunicatione one request-response. i want to measure how many response i receive in one second. i think that i have to know the moment when i do the request and the moment whene i receive the response and do the difference. The result(called delta) is the time-to response of device. in the end i have to do 1000ms/delta. how can calculate it ?

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  • Java EE@NYC Java Meetup

    - by reza_rahman
    On November 19th, I spoke at the New York City Java Meetup Group. It's a well-organized group led by my good friends Dario Laverde and Timothy Fagan - I have spoken there numerous times. I did my Java EE 7 talk (the same one from Java2Days 2012). JavaEE.Next(): Java EE 7, 8, and Beyond from reza_rahman The talk went very well -- the official RSVP shows 163 attended. I gave away a few GlassFish T-shirts, laptop stickers and Arun Gupta's Java EE 6 pocket guide. More details on the talk here. I most certainly look forward to speaking there again.

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  • File.mkdir is not working and I can't understand why

    - by gotch4
    Hello, I've this brief snippet: String target = baseFolder.toString() + entryName; target = target.substring(0, target.length() - 1); File targetdir = new File(target); if (!targetdir.mkdirs()) { throw new Exception("Errore nell'estrazione del file zip"); } doesn't mattere if I leave the last char (that is usually a slash). It's done this way to work on both unix and windows. The path is actually obtained from the URI of the base folder. As you can see from baseFolder.toString() (baseFolder is of type URI and is correct). The base folder actually exists. I can't debug this because all I get is true or false from mkdir, no other explanations.The weird thing is that baseFolder is created as well with mkdir and in that case it works. Now I'm under windows. the value of target just before the creation of targetdir is "file:/C:/Users/dario/jCommesse/jCommesseDB" if I cut and paste it (without the last entry) in windows explore it works...

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  • Importing a CSV file without headers into SQL 2008

    - by Luiggi
    I want to import a CSV with 4,8M records into a SQL 2008 table. I'm trying to do it with the Management Studio wizard but it keeps trying to recognize a header row which the CSV doesnt have. I don't find any option to skip this and although I specify the columns myself, the wizard still tries to find a header row and doesnt import anything without it. The structure of the CSV is "818180","25529","Dario","Pereyra","Rosario","SF","2010-09-02" I've also tried alternatives like BULK INSERT but then I find out that with BULK INSERT I can't import files with a text qualifier.

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  • HP P212 hangs on Initializing

    - by user927586
    I'm in trouble... Server: HP Microserver N36L Storage: HP P212/256 with BBWC Drives: 4 WD 2 Tb While expanding the RAID 5 array from 3 to 4 drives, the server rebooted itself. Expansion was at 76%. Now at boot the P212 seems to hang on initializing. After some time screen resets and the server boots, but in the os (Windows Server 2008R2) the P212 has errors (error code 10) and it's not seen by the HP ACU. Whats' going on? It's trying to complete the expansion? It's trying to make all over the expansion? It's simply stuck? What should I do? I NEED the data on the array! PS In the server BIOS, on the hd boot priority, the server still reports the array logical drive... maybe it's a good sign... PPS I'm not at the server physical location, so I cannot tell if the drives in the array are being accessed (that would be the case if the controller it's redoing/completing the expansion process) or not right now. Bye Dario

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  • puma init.d for centos 6 fails with runuser: user /var/log/puma.log does not exist

    - by Rubytastic
    Trying to get a init.d/puma to work on Centos 6. It throws error runuser: user /var/log/puma.log does not exist I run this from the /srv/books/current folder but it fails. I tried to debug the values but not quite get what is missing and why it throws this error. #! /bin/sh # puma - this script starts and stops the puma daemon # # chkconfig: - 85 15 # description: Puma # processname: puma # config: /etc/puma.conf # pidfile: /srv/books/current/tmp/pids/puma.pid # Author: Darío Javier Cravero &lt;[email protected]> # # Do NOT "set -e" # Original script https://github.com/puma/puma/blob/master/tools/jungle/puma # It was modified here by Stanislaw Pankevich <[email protected]> # to run on CentOS 5.5 boxes. # Script works perfectly on CentOS 5: script uses its native daemon(). # Puma is being stopped/restarted by sending signals, control app is not used. # Source function library. . /etc/rc.d/init.d/functions # Source networking configuration. . /etc/sysconfig/network # Check that networking is up. [ "$NETWORKING" = "no" ] && exit 0 # PATH should only include /usr/* if it runs after the mountnfs.sh script PATH=/usr/local/bin:/usr/local/sbin/:/sbin:/usr/sbin:/bin:/usr/bin DESC="Puma rack web server" NAME=puma DAEMON=$NAME SCRIPTNAME=/etc/init.d/$NAME CONFIG=/etc/puma.conf JUNGLE=`cat $CONFIG` RUNPUMA=/usr/local/bin/run-puma # Skipping the following non-CentOS string # Load the VERBOSE setting and other rcS variables # . /lib/init/vars.sh # CentOS does not have these functions natively log_daemon_msg() { echo "$@"; } log_end_msg() { [ $1 -eq 0 ] && RES=OK; logger ${RES:=FAIL}; } # Define LSB log_* functions. # Depend on lsb-base (>= 3.0-6) to ensure that this file is present. . /lib/lsb/init-functions # # Function that performs a clean up of puma.* files # cleanup() { echo "Cleaning up puma temporary files..." echo $1; PIDFILE=$1/tmp/puma/puma.pid STATEFILE=$1/tmp/puma/puma.state SOCKFILE=$1/tmp/puma/puma.sock rm -f $PIDFILE $STATEFILE $SOCKFILE } # # Function that starts the jungle # do_start() { log_daemon_msg "=> Running the jungle..." for i in $JUNGLE; do dir=`echo $i | cut -d , -f 1` user=`echo $i | cut -d , -f 2` config_file=`echo $i | cut -d , -f 3` if [ "$config_file" = "" ]; then config_file="$dir/puma/config.rb" fi log_file=`echo $i | cut -d , -f 4` if [ "$log_file" = "" ]; then log_file="$dir/puma/puma.log" fi do_start_one $dir $user $config_file $log_file done } do_start_one() { PIDFILE=$1/puma/puma.pid if [ -e $PIDFILE ]; then PID=`cat $PIDFILE` # If the puma isn't running, run it, otherwise restart it. if [ "`ps -A -o pid= | grep -c $PID`" -eq 0 ]; then do_start_one_do $1 $2 $3 $4 else do_restart_one $1 fi else do_start_one_do $1 $2 $3 $4 fi } do_start_one_do() { log_daemon_msg "--> Woke up puma $1" log_daemon_msg "user $2" log_daemon_msg "log to $4" cleanup $1; daemon --user $2 $RUNPUMA $1 $3 $4 } # # Function that stops the jungle # do_stop() { log_daemon_msg "=> Putting all the beasts to bed..." for i in $JUNGLE; do dir=`echo $i | cut -d , -f 1` do_stop_one $dir done } # # Function that stops the daemon/service # do_stop_one() { log_daemon_msg "--> Stopping $1" PIDFILE=$1/tmp/puma/puma.pid STATEFILE=$1/tmp/puma/puma.state echo $PIDFILE if [ -e $PIDFILE ]; then PID=`cat $PIDFILE` echo "Pid:" echo $PID if [ "`ps -A -o pid= | grep -c $PID`" -eq 0 ]; then log_daemon_msg "---> Puma $1 isn't running." else log_daemon_msg "---> About to kill PID `cat $PIDFILE`" # pumactl --state $STATEFILE stop # Many daemons don't delete their pidfiles when they exit. kill -9 $PID fi cleanup $1 else log_daemon_msg "---> No puma here..." fi return 0 } # # Function that restarts the jungle # do_restart() { for i in $JUNGLE; do dir=`echo $i | cut -d , -f 1` do_restart_one $dir done } # # Function that sends a SIGUSR2 to the daemon/service # do_restart_one() { PIDFILE=$1/tmp/puma/puma.pid i=`grep $1 $CONFIG` dir=`echo $i | cut -d , -f 1` if [ -e $PIDFILE ]; then log_daemon_msg "--> About to restart puma $1" # pumactl --state $dir/tmp/puma/state restart kill -s USR2 `cat $PIDFILE` # TODO Check if process exist else log_daemon_msg "--> Your puma was never playing... Let's get it out there first" user=`echo $i | cut -d , -f 2` config_file=`echo $i | cut -d , -f 3` if [ "$config_file" = "" ]; then config_file="$dir/config/puma.rb" fi log_file=`echo $i | cut -d , -f 4` if [ "$log_file" = "" ]; then log_file="$dir/log/puma.log" fi do_start_one $dir $user $config_file $log_file fi return 0 } # # Function that statuss then jungle # do_status() { for i in $JUNGLE; do dir=`echo $i | cut -d , -f 1` do_status_one $dir done } # # Function that sends a SIGUSR2 to the daemon/service # do_status_one() { PIDFILE=$1/tmp/puma/pid i=`grep $1 $CONFIG` dir=`echo $i | cut -d , -f 1` if [ -e $PIDFILE ]; then log_daemon_msg "--> About to status puma $1" pumactl --state $dir/tmp/puma/state stats # kill -s USR2 `cat $PIDFILE` # TODO Check if process exist else log_daemon_msg "--> $1 isn't there :(..." fi return 0 } do_add() { str="" # App's directory if [ -d "$1" ]; then if [ "`grep -c "^$1" $CONFIG`" -eq 0 ]; then str=$1 else echo "The app is already being managed. Remove it if you want to update its config." exit 1 fi else echo "The directory $1 doesn't exist." exit 1 fi # User to run it as if [ "`grep -c "^$2:" /etc/passwd`" -eq 0 ]; then echo "The user $2 doesn't exist." exit 1 else str="$str,$2" fi # Config file if [ "$3" != "" ]; then if [ -e $3 ]; then str="$str,$3" else echo "The config file $3 doesn't exist." exit 1 fi fi # Log file if [ "$4" != "" ]; then str="$str,$4" fi # Add it to the jungle echo $str >> $CONFIG log_daemon_msg "Added a Puma to the jungle: $str. You still have to start it though." } do_remove() { if [ "`grep -c "^$1" $CONFIG`" -eq 0 ]; then echo "There's no app $1 to remove." else # Stop it first. do_stop_one $1 # Remove it from the config. sed -i "\\:^$1:d" $CONFIG log_daemon_msg "Removed a Puma from the jungle: $1." fi } case "$1" in start) [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME" if [ "$#" -eq 1 ]; then do_start else i=`grep $2 $CONFIG` dir=`echo $i | cut -d , -f 1` user=`echo $i | cut -d , -f 2` config_file=`echo $i | cut -d , -f 3` if [ "$config_file" = "" ]; then config_file="$dir/config/puma.rb" fi log_file=`echo $i | cut -d , -f 4` if [ "$log_file" = "" ]; then log_file="$dir/log/puma.log" fi do_start_one $dir $user $config_file $log_file fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; stop) [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME" if [ "$#" -eq 1 ]; then do_stop else i=`grep $2 $CONFIG` dir=`echo $i | cut -d , -f 1` do_stop_one $dir fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; status) # TODO Implement. log_daemon_msg "Status $DESC" "$NAME" if [ "$#" -eq 1 ]; then do_status else i=`grep $2 $CONFIG` dir=`echo $i | cut -d , -f 1` do_status_one $dir fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; restart) log_daemon_msg "Restarting $DESC" "$NAME" if [ "$#" -eq 1 ]; then do_restart else i=`grep $2 $CONFIG` dir=`echo $i | cut -d , -f 1` do_restart_one $dir fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; add) if [ "$#" -lt 3 ]; then echo "Please, specifiy the app's directory and the user that will run it at least." echo " Usage: $SCRIPTNAME add /path/to/app user /path/to/app/config/puma.rb /path/to/app/config/log/puma.log" echo " config and log are optionals." exit 1 else do_add $2 $3 $4 $5 fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; remove) if [ "$#" -lt 2 ]; then echo "Please, specifiy the app's directory to remove." exit 1 else do_remove $2 fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; *) echo "Usage:" >&2 echo " Run the jungle: $SCRIPTNAME {start|stop|status|restart}" >&2 echo " Add a Puma: $SCRIPTNAME add /path/to/app user /path/to/app/config/puma.rb /path/to/app/config/log/puma.log" echo " config and log are optionals." echo " Remove a Puma: $SCRIPTNAME remove /path/to/app" echo " On a Puma: $SCRIPTNAME {start|stop|status|restart} PUMA-NAME" >&2 exit 3 ;; esac :

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  • UiPickerView change font color according data

    - by Fulkron
    I'm using a pickerView with multiple components related to several fields in a Database (CoreData). Is it possible to change the fontcolor for a specific component according the presence of data in the DB ? For example the field in the DB is null the component font color should be RED otherwise black. Any help will be appreciated ! Dario ================== Thanks Kenny, I have to apply to a single UIPicker only. So I', returning the view parametere (without modificatiosn). The result is all the pickers show empty rows. Thanks for help ! Here you will find the code fragment: - (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view { if (pickerView == tipoPk){ UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 100,30)]; label.textColor = [UIColor redColor]; switch (component) { case PK_Tipo: label.text = [tipoArray objectAtIndex:row]]; break; case PK_Settore: label.text = [settoreArray objectAtIndex:row]]; break; default: break; } return label; } else { return view; // <==== return view for non related pickerviews , but no rows shown } }

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  • The Java Specialist: An Interview with Java Champion Heinz Kabutz

    - by Janice J. Heiss
    Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers. Originally published on blogs.oracle.com/javaone.

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  • The Java Specialist: An Interview with Java Champion Heinz Kabutz

    - by Janice J. Heiss
    Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers.

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  • OpenXML sdk Modify a sheet in my Excel document

    - by user465202
    hi! I create an empty template in excel. I would like to open the template and edit the document but I do not know how to change the existing sheet. That's the code: using (SpreadsheetDocument xl = SpreadsheetDocument.Open(filename, true)) { WorkbookPart wbp = xl.WorkbookPart; WorkbookPart workbook = xl.WorkbookPart; // Get the worksheet with the required name. // To be used to match the ID for the required sheet data // because the Sheet class and the SheetData class aren't // linked to each other directly. Sheet s = null; if (wbp.Workbook.Sheets.Elements().Count(nm = nm.Name == sheetName) == 0) { // no such sheet with that name xl.Close(); return; } else { s = (Sheet)wbp.Workbook.Sheets.Elements().Where(nm = nm.Name == sheetName).First(); } WorksheetPart wsp = (WorksheetPart)xl.WorkbookPart.GetPartById(s.Id.Value); Worksheet worksheet = new Worksheet(); SheetData sd = new SheetData(); //SheetData sd = (SheetData)wsp.Worksheet.GetFirstChild(); Stylesheet styleSheet = workbook.WorkbookStylesPart.Stylesheet; //SheetData sheetData = new SheetData(); //build the formatted header style UInt32Value headerFontIndex = util.CreateFont( styleSheet, "Arial", 10, true, System.Drawing.Color.Red); //build the formatted date style UInt32Value dateFontIndex = util.CreateFont( styleSheet, "Arial", 8, true, System.Drawing.Color.Black); //set the background color style UInt32Value headerFillIndex = util.CreateFill( styleSheet, System.Drawing.Color.Black); //create the cell style by combining font/background UInt32Value headerStyleIndex = util.CreateCellFormat( styleSheet, headerFontIndex, headerFillIndex, null); /* * Create a set of basic cell styles for specific formats... * If you are controlling your table then you can simply create the styles you need, * this set of code is still intended to be generic. */ _numberStyleId = util.CreateCellFormat(styleSheet, null, null, UInt32Value.FromUInt32(3)); _doubleStyleId = util.CreateCellFormat(styleSheet, null, null, UInt32Value.FromUInt32(4)); _dateStyleId = util.CreateCellFormat(styleSheet, null, null, UInt32Value.FromUInt32(14)); _textStyleId = util.CreateCellFormat(styleSheet, headerFontIndex, headerFillIndex, null); _percentageStyleId = util.CreateCellFormat(styleSheet, null, null, UInt32Value.FromUInt32(9)); util.AddNumber(xl, sheetName, (UInt32)3, "E", "27", _numberStyleId); util.AddNumber(xl, sheetName, (UInt32)3, "F", "3.6", _doubleStyleId); util.AddNumber(xl, sheetName, (UInt32)5, "L", "5", _percentageStyleId); util.AddText(xl, sheetName, (UInt32)5, "M", "Dario", _textStyleId); util.AddDate(xl, sheetName, (UInt32)3, "J", DateTime.Now, _dateStyleId); util.AddImage(xl, sheetName, imagePath, "Smile", "Smile", 30, 30); util.MergeCells(xl, sheetName, "D12", "F12"); //util.DeleteValueCell(spreadsheet, sheetName, "F", (UInt32)8); txtCellText.Text = util.GetCellValue(xl, sheetName, (UInt32)5, "M"); double number = util.GetCellDoubleValue(xl, sheetName, (UInt32)3, "E"); double numberD = util.GetCellDoubleValue(xl, sheetName, (UInt32)3, "F"); DateTime datee = util.GetCellDateTimeValue(xl, sheetName, (UInt32)3, "J"); //txtDoubleCell.Text = util.GetCellValue(spreadsheet, sheetName, (UInt32)3, "P"); txtPercentualeCell.Text = util.GetCellValue(xl, sheetName, (UInt32)5, "L"); string date = util.GetCellValue(xl, sheetName, (UInt32)3, "J"); double dateD = Convert.ToDouble(date); DateTime dateTime = DateTime.FromOADate(dateD); txtDateCell.Text = dateTime.ToShortDateString(); //worksheet.Append(sd); /* Columns columns = new Columns(); columns.Append(util.CreateColumnData(10, 10, 40)); worksheet.Append(columns); */ SheetProtection sheetProtection1 = new SheetProtection() { Sheet = true, Objects = true, Scenarios = true, SelectLockedCells = true, SelectUnlockedCells = true }; worksheet.Append(sheetProtection1); wsp.Worksheet = worksheet; wsp.Worksheet.Save(); xl.WorkbookPart.Workbook.Save(); xl.Close(); thanks!

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