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Why should the “PIMPL” idiom be used? [duplicate]
...() to be able to use private members of CatImpl. Cat::Purr() would not be allowed such an access without a friend declaration.
Because you then don't mix responsibilities: one class implements, one class forwards.
share...
How to use a servlet filter in Java to change an incoming servlet request url?
... a check in the code if the URL needs to be changed and if not, then just call FilterChain#doFilter(), else it will call itself in an infinite loop.
Alternatively you can also just use an existing 3rd party API to do all the work for you, such as Tuckey's UrlRewriteFilter which can be configured th...
LINQ equivalent of foreach for IEnumerable
...Multi-threading, possible by PLINQ. 2. Exceptions, you may want to collect all exception in the loop and throw it at once; and they are noise codes.
– Dennis C
Feb 7 '10 at 7:06
13...
Why is Multiple Inheritance not allowed in Java or C#?
I know that multiple inheritance is not allowed in Java and C#. Many books just say, multiple inheritance is not allowed. But it can be implemented by using interfaces. Nothing is discussed about why it is not allowed. Can anybody tell me precisely why it is not allowed?
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Creating an abstract class in Objective-C
I'm originally a Java programmer who now works with Objective-C. I'd like to create an abstract class, but that doesn't appear to be possible in Objective-C. Is this possible?
...
Array vs. Object efficiency in JavaScript
...an array, too:
var a3 = [];
a3[29938] = "a";
a3[32994] = "b";
It's basically an array with holes in it, because every array does have continous indexing. It's slower than arrays without holes. But iterating manually through the array is even slower (mostly).
This is an object:
var a3 = {};
a3[2...
Recommended way to save uploaded files in a servlet application
...e server's work folder get synced with last updates (this is in IDE terms called "publishing"). This is the main cause of the problem you're seeing.
In real world code there are circumstances where storing uploaded files in the webapp's deploy folder will not work at all. Some servers do (either by...
When to use virtual destructors?
...
Virtual destructors are useful when you might potentially delete an instance of a derived class through a pointer to base class:
class Base
{
// some virtual methods
};
class Derived : public Base
{
~Derived()
{
// Do some important cleanup
}
};
Her...
Tracing XML request/responses with JAX-WS
...
Following options enable logging of all communication to the console (technically, you only need one of these, but that depends on the libraries you use, so setting all four is safer option). You can set it in the code like in example, or as command line parame...
check if a std::vector contains a certain object? [duplicate]
Is there something in <algorithm> which allows you to check if a std:: container contains something? Or, a way to make one, for example:
...