You’re basically right, dynamic polymorphism (inheritance, virtuals) is generally the right choice when the type should be allowed to change at runtime (for example in plugin architectures). Static polymorphism (templates) is a better choice if the type should only change at compile-time. The only potential downsides to templates are that 1) they generally have to … Read more
The common way is to just call foo(); without casting into (void). He who has never ignored printf()‘s return value, cast the first stone.
TextAppearance.Holo.Widget.ActionBar.Title appears to have been added in API Level 13. Make sure your build target is set to 13, not just 11.
In Effective Java, 2nd edition, Joshua Bloch certainly recommends the former. There are a few reasons I can remember, and doubtless some I can’t: You can give the method a meaningful name. If you’ve got two ways of constructing an instance both of which take an int, but have different meanings for that int, using … Read more
I always try to reduce levels of nesting for readability and maintainability. If you have n try/catch blocks, each handling the same type of exception, why not refactor the code that can throw the exception into methods…it would look something like: try { firstBatchOfTricky(); secondBatchOfTricky(); …. nthBatchOfTricky(); } catch (ItWentBoomException e) { // recover from … Read more
If you want the attribute to be shared by all instances of the class, use a class attribute: class A(object): foo = None This causes (‘foo’,None) to be a (key,value) pair in A.__dict__. If you want the attribute to be customizable on a per-instance basis, use an instance attribute: class A(object): def __init__(self): self.foo = … Read more
Semantically, they are identical. However, I’d recommend using the latter syntax (String[] args) when declaring arrays. The former syntax is there mainly for compatibility with C syntax. Since String[], as a whole, is the type of the object in Java, it’s more consistent and clear not to split it up. A similar question addresses the … Read more
It’s not about lines of code. As Steve Mcconnell and Bob Martin say (two pretty good references on coding best practices), a method should do one thing and only one thing. However many lines of code it takes to do that one thing is how many lines it should have. If that “one thing” can … Read more
How about such approach: int getSize(int v) { int[] thresholds = {145, 117, 68, 51, 22, 10}; for (int i = 0; i < thresholds.length; i++) { if (v > thresholds[i]) return i+1; } return 1; } Functionally: (Demonstrated in Scala) def getSize(v: Int): Int = { val thresholds = Vector(145, 117, 68, 51, 22, … Read more
I personally prefer typeof callback === ‘function’ && callback(); The typeof command is dodgy however and should only be used for “undefined” and “function” The problems with the typeof !== undefined is that the user might pass in a value that is defined and not a function