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How to start two threads at “exactly” the same time
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// Now if we block on the gate from the main thread, it will open
// and all threads will start to do stuff!
gate.await();
System.out.println("all threads started");
This doesn't have to be a CyclicBarrier, you could also use a CountDownLatch or even a lock.
This still can't make sure that ...
Which iomanip manipulators are 'sticky'?
... the comments below:
By Martin:
@Chareles: Then by this requirement all manipulators are sticky. Except setw which seems to be reset after use.
By Charles:
Exactly! and the only reason that setw appears to behave differently is because there are requirements on formatted output operat...
Rename all files in directory from $filename_h to $filename_half?
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Just use bash, no need to call external commands.
for file in *_h.png
do
mv "$file" "${file/_h.png/_half.png}"
done
Do not add #!/bin/sh
For those that need that one-liner:
for file in *.png; do mv "$file" "${file/_h.png/_half.png}"; done
...
Closing JDBC Connections in Pool
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Yes, certainly you need to close the pooled connection as well. It's actually a wrapper around the actual connection. It wil under the covers release the actual connection back to the pool. It's further up to the pool to decide whether the actual connection will actually be closed or be reused for...
Should __init__() call the parent class's __init__()?
...
In Python, calling the super-class' __init__ is optional. If you call it, it is then also optional whether to use the super identifier, or whether to explicitly name the super class:
object.__init__(self)
In case of object, calling th...
Why covariance and contravariance do not support value type
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Basically, variance applies when the CLR can ensure that it doesn't need to make any representational change to the values. References all look the same - so you can use an IEnumerable<string> as an IEnumerable<object>...
get current url in twig template?
...ttributes.get('_route_params')) %}
The app global view variable contains all sorts of useful shortcuts, such as app.session and app.security.token.user, that reference the services you might use in a controller.
share
...
Can you make just part of a regex case-insensitive?
...ase-insensitive by using the (?i:) pattern modifier.
Modern regex flavors allow you to apply modifiers to only part of the regular expression. If you insert the modifier (?ism) in the middle of the regex, the modifier only applies to the part of the regex to the right of the modifier. You can turn ...
When to add what indexes in a table in Rails
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Should I add "index" to all the foreign keys like "xxx_id"?
It would be better, because it accelerates the search in sorting in this column. And Foreign keys are something searched for a lot.
Since Version 5 of rails the index will be created aut...
Why use Abstract Base Classes in Python?
...emented classes.
Long version
There is a contract between a class and its callers. The class promises to do certain things and have certain properties.
There are different levels to the contract.
At a very low level, the contract might include the name of a method or its number of parameters.
In a s...