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How to establish a connection pool in JDBC?
...vailable 3rd party components:
Apache DBCP - This one is
used internally by Tomcat, and by
yours truly.
c3p0
Apache DBCP comes with different example on how to setup a pooling javax.sql.DataSource. Here is one sample that can help you get started.
...
Shell - Write variable contents to a file
...able:
starts with -e
starts with -n
starts with -E
contains a \ followed by an n
should not have an extra newline appended after it
and so they cannot be relied upon for arbitrary string contents.
In bash, you can use "here strings" as:
cat <<< "$var" > "$destdir"
As noted in t...
How to create a protocol with methods that are optional?
...ier for a method after compilation. You can provide the correct identifier by using the @selector() directive and specifying the name of the method.
If the data source in this example implements the method, the title is used; otherwise, the title remains nil.
...
Interfaces vs. abstract classes [duplicate]
...seems to show the answerer's bias ("advantages of abstract class" followed by four bullets of advantages followed by "interfaces are merely" followed by a single "however" in favor of interfaces) toward abstract classes much more than really describe the differences between abstract classes and inte...
An efficient way to transpose a file in Bash
...$ ./shell.sh
0 3 6 9
1 4 7 10
2 5 8 11
Performance against Perl solution by Jonathan on a 10000 lines file
$ head -5 file
1 0 1 2
2 3 4 5
3 6 7 8
4 9 10 11
1 0 1 2
$ wc -l < file
10000
$ time perl test.pl file >/dev/null
real 0m0.480s
user 0m0.442s
sys 0m0.026s
$ time awk -f ...
Where is nodejs log file?
...
There is no log file. Each node.js "app" is a separate entity. By default it will log errors to STDERR and output to STDOUT. You can change that when you run it from your shell to log to a file instead.
node my_app.js > my_app_log.log 2> my_app_err.log
Alternatively (recommended...
Create a “with” block on several context managers? [duplicate]
...or instance A lock, a db connection and an ip socket.
You can acquire them by:
5 Answers
...
Why not infer template parameter from constructor?
...
@KyleStrand Yes, by saying 'class template arguments cannot be deduced from their constructors because [example that does not use any constructor]', this answer is completely irrelevant. I genuinely can't believe it was accepted, reached +29,...
How to empty/destroy a session in rails?
...er.
reset_session
Here's the documentation on this method: http://api.rubyonrails.org/classes/ActionController/Base.html#M000668
Resets the session by clearing out all
the objects stored within and
initializing a new session object.
Good luck!
...
Recursively counting files in a Linux directory
...and's standard input.
wc (short for word count) counts newlines, words and bytes on its input (docs).
-l to count just newlines.
Notes:
Replace DIR_NAME with . to execute the command in the current folder.
You can also remove the -type f to include directories (and symlinks) in the count.
It's ...