B4J Question Check if the .jar is already runing

R

Roycefer

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• Aug 24, 2015

• #2

When the .jar first starts up, check for a file called "running.txt". If it doesn't exist, create it. If it does exist, post a message saying "can't have two instances of this app running" and then shutdown. When the user closes the app, don't forget to delete "running.txt".

 

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Douglas Farias

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• Aug 24, 2015

• #3

any other way? for example check on taskmanager (system process) if this is running and show a msg?
i already have this ideia of txt file, but i remember the user can use ALT + F4 and i cant delete txt in this case

 

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R

Roycefer

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• Aug 24, 2015

• #4

All java processes show up as java.exe in the Task Manager. That won't be of any use to you. Erel had the idea to open up a Socket on (say) port 12345. Attempting to open a socket on this port will fail if another program has already opened a socket on that port. Ideally, the port should be released when the process ends, regardless of how it ends, but I would test that to make sure.

 

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Douglas Farias

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• Aug 24, 2015

• #5

hmm, nice ideia i will try

 

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Erel

B4X founder

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• Aug 24, 2015

• #6

Build an installer for your app with B4JPackager and then the file will be a regular executable.
Check the running processes with jShell (tasklist on Windows / ps on Mac and linux).

 

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BeneBarros

Active Member

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Longtime User

• Aug 25, 2015

• #7

I use a SQLite file.

B4X:

TempPath = Utils.GetCanonicalPath (File.DirTemp)
lbInfo.Text = "Deleting old database"
If File.Exists (TempPath, "Databs.db") Then
    If Not (File.Delete (TempPath, "Databs.db")) Then
        msgbox.show ("Databs.db is in use. Stopping system.")
        ExitApplication
    end If
end If
CallSubDelayed (Me, "IniSql") 'create and initialize the file Databs.db

 

Last edited: Aug 25, 2015

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