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Optimistic vs. Pessimistic locking
...database systems define terms such as SESSION setting.
Nowadays, over the Internet, we no longer execute reads and writes in the context of the same database transaction, and ACID is no longer sufficient.
For instance, consider the following use case:
Without optimistic locking, there is no way...
Suppress warning “Category is implementing a method which will also be implemented by its primary cl
...in it. Ideally, singletons should be injected into code as a protocol, allowing you to switch out the implementation. But if you already have one embedded inside your code, you can add a category of the singleton in your unit test and overide the sharedInstance and the methods you what to control to...
Why does Java's hashCode() in String use 31 as a multiplier?
... subtract instruction. However, if your multiplier is slow this is still a win. Modern processors tend to have fast multipliers so it doesn't make much difference, so long as 32 goes on the correct side.
It's not a great hash algorithm, but it's good enough and better than the 1.0 code (and very mu...
CMake: Print out all accessible variables in a script
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Using the get_cmake_property function, the following loop will print out all CMake variables defined and their values:
get_cmake_property(_variableNames VARIABLES)
list (SORT _variableNames)
foreach (_variableName ${_variableNames})
message(STATUS "${_variableName}=${...
Web deployment task build failed
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Still at Feb 2016, i encountered this weird problem on windows server 2008R2 and your solution worked for me.
– Ehsan Mirsaeedi
Feb 4 '16 at 23:02
2
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Type definition in object literal in TypeScript
....7
state.instance && state.instance.fun();
// Or the long winded way because the above just feels weird
if (state.instance) { state.instance.fun(); }
// Or the I came from C and can't check for nulls like they are booleans way
if (state.instance != null) { state.instanc...
When to use enumerateObjectsUsingBlock vs. for
...mes down to personal preference. For me, the idiomatic and readable option wins. In this case, that is Fast Enumeration using for-in.
Benchmark:
NSMutableArray *arr = [NSMutableArray array];
for (int i = 0; i < 100; i++) {
arr[i] = [NSString stringWithFormat:@"%d", i];
}
int i;
__block NSUI...
Yes/No message box using QMessageBox
...rk on Qt 4 and 5, requires QT += widgets on Qt 5, and CONFIG += console on Win32 to see qDebug() output.
See the StandardButton enum to get a list of buttons you can use; the function returns the button that was clicked. You can set a default button with an extra argument (Qt "chooses a suitable de...
What should I do when 'svn cleanup' fails?
...be of interest for somebody. You can delete them recursively with the following command: rm -rf find . -type f -name lock
– H6.
Jan 20 '12 at 14:47
1
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Java: how do I get a class literal from a generic type?
...methods a la Method method = clzz.getDeclaredMethod("getSomeFoo"); so much win! Thank YOU!
– Naruto Sempai
Feb 9 '17 at 2:12
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