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Using a strategy pattern and a command pattern
Both design patterns encapsulate an algorithm and decouple implementation details from their calling classes. The only difference I can discern is that the Strategy pattern takes in parameters for execution, while the Command pattern doesn't.
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What does “Changes not staged for commit” mean
...made since the last commit. For example, let's say you have file a, file b and file c. You modify file a and file b but the changes are very different in nature and you don't want all of them to be in one single commit. You issue
git add a
git commit a -m "bugfix, in a"
git add b
git commit b -m "n...
How to hide element using Twitter Bootstrap and show it using jQuery?
...ated,
.hide is available, but it does not always affect screen readers and is deprecated as of v3.0.1
Second, use jQuery's .toggleClass(), .addClass() and .removeClass()
<div id="myId" class="hidden">Foobar</div>
To show it: $("#myId").removeClass('hidden');
To hide it: $("#myI...
Importance of varchar length in MySQL table
...serted dynamically. Because I can not be certain of the length of strings and do not want them cut off, I make them varchar(200) which is generally much bigger than I need. Is there a big performance hit in giving a varchar field much more length than necessary?
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Why is React's concept of Virtual DOM said to be more performant than dirty model checking?
...talk at ( Pete Hunt: React: Rethinking best practices -- JSConf EU 2013 ) and the speaker mentioned that dirty-checking of the model can be slow. But isn't calculating the diff between virtual DOMs actually even less performant since the virtual DOM, in most of the cases, should be bigger than mode...
Java Multiple Inheritance
In an attempt to fully understand how to solve Java's multiple inheritance problems I have a classic question that I need clarified.
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Difference between Repository and Service Layer?
...OOP Design Patterns, what is the difference between the Repository Pattern and a Service Layer?
5 Answers
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Covariance, Invariance and Contravariance explained in plain English?
Today, I read some articles about Covariance, Contravariance (and Invariance) in Java. I read the English and German Wikipedia article, and some other blog posts and articles from IBM.
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Check if a variable is a string in JavaScript
... in the case of strings created with new String(), but this is seldom used and recommended against[1][2]. See the other answers for how to handle these, if you so desire.
The Google JavaScript Style Guide says to never use primitive object wrappers.
Douglas Crockford recommended that primitive o...
Android Studio installation on Windows 7 fails, no JDK found
I downloaded Android Studio and attempted to launch the program.
29 Answers
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