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Why are Objective-C delegates usually given the property assign instead of retain?
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A creates B
A sets itself as B's delegate
…
A is released by its owner
If B had retained A, A wouldn't be released, as B owns A, thus A's dealloc would never get called, causing both A and B to leak.
You shouldn't worry about A going away because it owns B and thus gets rid of it in dealloc.
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How to view the SQL queries issued by JPA?
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Logging options are provider-specific. You need to know which JPA implementation do you use.
Hibernate (see here):
<property name = "hibernate.show_sql" value = "true" />
EclipseLink (see here):
<property name="eclipselink.logging.level" value=...
How to have multiple CSS transitions on an element?
...dow .2s;
}
ease is the default timing function, so you don't have to specify it. If you really want linear, you will need to specify it:
transition: color .2s linear, text-shadow .2s linear;
This starts to get repetitive, so if you're going to be using the same times and timing functions across...
Determine path of the executing script
...passed by Rscript to the actual R interpreter and search them for --file=. If your script was launched from the path or if it was launched with a full path, the script.name below will start with a '/'. Otherwise, it must be relative to the cwd and you can concat the two paths to get the full path.
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Difference between HashSet and HashMap?
...from the fact that HashSet does not allow duplicate values, what is the difference between HashMap and HashSet ?
19 An...
When to use nested classes and classes nested in modules?
...n’t have that behaviour.
In Ruby,
class Car
class Wheel
end
end
differs from
class Car
end
class Wheel
end
only in the name of the class Wheel vs. Car::Wheel. This difference in name can make explicit to programmers that the Car::Wheel class can only represent a car wheel, as opposed t...
Where can I find the TypeScript version installed in Visual Studio?
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If you only have TypeScript installed for Visual Studio then:
Start the Visual Studio Command Prompt
Type tsc -v and hit Enter
Visual Studio 2017 versions 15.3 and above bind the TypeScript version to individual project...
RESTful web service - how to authenticate requests from other services?
... option but it does have the benefit of being quite simple. The client certificate is also good but is it really much different? There's a cert on the server and one on the client. It's main advantage is that it's harder to brute force. Hopefully you've got other protections in place to protect agai...
What is the default access modifier in Java? [duplicate]
What is the default access modifier for a method or an instance variable if I do not state it explicitly?
13 Answers
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How to calculate percentage with a SQL statement
... the table will be scanned twice. Also the query will not look that simple if there is more than one table referenced.
– Alex Aza
May 19 '11 at 21:15
14
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