Design Pattern, Implementation Pattern and Best Practices

[bluedes]

one line man gihapon to akong gi pang edit ila lang gi butang sa nested if statements., if it requires you to include try-catch-throw statements, better not to use ternary operators also.

huh? one-line ifs na gi butang sa nested if statements?

di ba na contradictory? mao gani one-life ifs, unya inside nested na nuon?

naglibog na jud ko unsa imo point..

[torade]

semantically, there's no difference between the two.. this practice is just to help the compiler spot an error if in case only 1 equals sign was written


if ( variable == TRUE )

when mistakenly written as

if ( variable = TRUE )

will not trigger a compiler error even though logically, error na na..


but kung balehon nimo..

if ( TRUE == variable )

a mistake like this

if ( TRUE = variable )

will be spotted by compiler right away..

I like this logic... at first I was thinking it's not useful and still the same with the first IF statement but as I read over I found it good to implement. I often stumble a mistake that you mentioned. Thanks for this.

[silent-kill]

ternary operators are useful for simple one liner statement.

i saw some ternary operator being abused in a php code it was hell, tracing it lol



i use watch if im debugging multiple functions, that are using a common variable name inside.

func1() {
 x = blah blah
}

func2() {
 x = blah blah 2
}

another design pattern i see useful is a class factory.

i dont want to talk about it cuz google does a better job LOL.

[bluedes]

ternary operators are useful for simple one liner statement.

i saw some ternary operator being abused in a php code it was hell, tracing it lol



i use watch if im debugging multiple functions, that are using a common variable name inside.

func1() {
 x = blah blah
}

func2() {
 x = blah blah 2
}

another design pattern i see useful is a class factory.

i dont want to talk about it cuz google does a better job LOL.

class factory =? singleton? or the one where the class also has a mechanism for handling its instances...?

either ways, yes, I also use those models.. it's very nice..

[silent-kill]

singleton is a pattern used to insure you only have 1 instance of that class for the entire lifespan of the assembly.

as for the class factory or factory design pattern.
Factory method pattern - Wikipedia, the free encyclopedia

[simoncpu]

class factory =? singleton? or the one where the class also has a mechanism for handling its instances...?

either ways, yes, I also use those models.. it's very nice..

Nope. A factory is an object that instantiates various classes, although the factory itself can be implemented as a singleton.

Analogy: a singleton is like a static variable in C. All instances of a singleton would refer to only one object. It's like a global variable in C (in fact, most people use singletons as replacements for globals).

[kamsky]

Problem: A thread instantiate a singleton, while it's not done instantiating, another thread instantiate the same singleton class. Now they are two instances.

So how do you ensure single instance in a Singleton in a multi-threaded environment?

[MarkCuering]

is this with respect to JAVA?

[kamsky]

is this with respect to JAVA?

applicable to any language.

[MarkCuering]

in C++/C# we have a volatile keyword: (can be useful across multiple domain under multithreaded application.)

The volatile keyword indicates that a field can be modified in the program by something such as the operating system, the hardware, or a concurrently executing thread. The volatile modifier is usually used for a field that is accessed by multiple threads without using the lock statement to serialize access. Using the volatile modifier ensures that one thread retrieves the most up-to-date value written by another thread.


if single domain only, locking/synchronization with static initialization approach is enough I guess.

there are variety of threading under managed/unmanaged world... If the implementation uses a ThreadPool under managed world, one can apply delay/sleep under Running State of the thread.