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What are the differences between Abstract Factory and Factory design patterns?

...le the desired object instantiation. The quote assumes that an object is calling its own factory method here. Therefore the only thing that could change the return value would be a subclass. The abstract factory is an object that has multiple factory methods on it. Looking at the first half of your...
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Rails 3 check if attribute changed

... Check out ActiveModel::Dirty (available on all models by default). The documentation is really good, but it lets you do things such as: @user.street1_changed? # => true/false share ...
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C/C++ NaN constant (literal)?

... Indeed, it's an option if you need obfuscation but not portability. Personally, I prefer portability without obfuscation, so I won't suggest it myself. – Mike Seymour May 22 '13 at 12:26 ...
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What is the best Distributed Brute Force countermeasure?

...so far I'm winning (so to speak). But I've run into a pretty non-trivial challenge (one that most auth libraries miss entirely, but I insist on handling it properly): how to deal intelligently with large-scale, distributed, variable-username brute-force attacks . ...
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Pointers vs. values in parameters and return values

... function values, and interface values are implemented with pointers internally, and a pointer to them is often redundant. Elsewhere, use pointers for big structs or structs you'll have to change, and otherwise pass values, because getting things changed by surprise via a pointer is confusing. O...
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Adding the “Clear” Button to an iPhone UITextField

... func clear_btn(box_is : UITextField){ box_is.clearButtonMode = .always if let clearButton = box_is.value(forKey: "_clearButton") as? UIButton { let templateImage = clearButton.imageView?.image?.withRenderingMode(.alway...
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What resources exist for Database performance-tuning? [closed]

...tabase, this guide may also help. http://download.oracle.com/docs/cd/B28359_01/server.111/b28274/toc.htm share | improve this answer | follow | ...
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Split string, convert ToList() in one line

...ers .Split(',') .Where(x => int.TryParse(x, out _)) .Select(int.Parse) .ToList(); share | improve this answer | follow ...
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How to refresh an IFrame using Javascript?

... var tmp_src = iframe.src; iframe.src = ''; iframe.src = tmp_src; – lyfing Jan 27 '15 at 8:28 2 ...
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How to select label for=“XYZ” in CSS?

... or some other structural way), sadly. (I'm assuming that the template {t _your_email} will fill in a field with id="email". If not, use a class instead.) Note that if the value of the attribute you're selecting doesn't fit the rules for a CSS identifier (for instance, if it has spaces or brackets...