Good practice/optimizing your plugins ?

hey ive not really see a thread about this but what ways could i make a plugin better and to optimize it without having it lag a server or just make it more simple

Any thoughts ?

 

This is actually a really good question IMO. I'd love to see a well thought out best practices thread here, possibly stickied. Unfortunately I haven't been doing this long enough to make such a thread myself, so if any plugin gurus out there would like to take a crack at it, I'm sure it would be much appreciated by the whole community.

 

It might not help all that much but when i code i try to make as few lines as possible. But i still leave the few separating lines so everything is still easy to find and read.

 

- Store your objects locally (instead of calling functions like event.getPlayer() every time)
- Don't use too many ifs inside ifs
- Generally, try to make your code efficent.

 

Try to avoid duplicate snippets of code.
If you need to do the same thing pretty often, make a new private method and put the repeating code inside there.

 

Be careful with collections. No seriously, I was generating entity lists in a function and it made the RAM usage go up 5 mb/s faster. When storing the lists locally and using clear on them, it even brought down the time it took to perform everything. (talking of NoLagg's item/orb stacking and entity spawn limit handling)

Also, be very careful with while loops. For example, when performing an operation until it succeeds. If you don't specify a counter-like thing it could loop for hours taking your thread/server down with it.

Ow and if possible, re-use your variables.

Code:

int value1 = 5;
int value2 = 7;
int result = 5 + 7;
//can be
int value1 = 5;
int value2 = 7;
value1 = value1 + value2;

Taking into account that you need value1 and value2 as variables. And, as stated above, try to prevent the creation of arrays/lists in functions. It can cause RAM usage to increase rapidly, making the Garbage Collector go into overdrive.

 

If you make a loop to try to find something use a break statement once you have found it.

 

if you don't need to know exactly when a player moves 0.005 blocks, don't just use onMove, add a if call to exit out if they are in the same "block location". Only run the expensive check when they've actually moved far enough.

 

Don't make a bunch of objects in loops.

NEVER use boxed primitives (except with lists, and the previous rule applies for those)

Use NMS code to squeeze out a little bit more speed, for example world.getHandle().setRawTypeId is a lot faster than world.getBlockAt(...).setTypeId because the bukkit method is creating a Block object just for you.

Generally try to make the code look as nice as possible, and if you think something could be done better, change it.

 

Think about the problem you're trying to solve carefully, and choose your data structures to match your problem.

Never use string concatenation inside a loop. Use StringBuilder or Joiner.

Cache the return value of expensive function calls wherever possible.

 

Have to say thank you for all these great comments

 

• Think about what the program should do and leave it at that
• Use polymorphism

 

Now your just throwing random words out of a dictionary in this topic!
OT: Polymorphism

 

ok, my input to this... REPOST all of this in NOOB speak..

It would be really cool if the more knowledgeable programmers would come up with a best practice wiki page / pages about how to code perhaps containing some snippet of code or even a reference to the source code etc...

I'm learning from books and good plugins... (codewise)... which I can notice because I have a little knowledge..

but a lot of the stuff you people throw around is common sense for real java programmers but gives you a Häääh????? from most of the programmers here, oh yeah and a lot of the people here neither speak english or java as a native language

 

Am not, polymorphism is crucial to any good structured Java program which is an Object Oriented platform. By this I mean heirarchy trees and actual objects such as (Player, Entity, etc) not (PlayerManager or EntityManager) some times this is difficult to dodge, but I try to use it whenever possible.

An example of poly morphism...

Dog extends Canine which extends Animal

 

That's what the wink smiley is for right?!

So what you mean is.

Creeper extends Monster which extends Creature (yay for javadocs!)

But how about a plugin example? How would you use it in a plugin? Got any real life examples?

 

TemplarNPC extends BasicHumanNPC, which extends BasicNPC (taken from NPC spawner lib =P)

 

use the final keyword for any variable you don't plan on reassigning. You are of course free to mutate said variable.

 

Yeah... But that's just the same as what I said about the Creeper... Other examples?

Edit: Sorry, maybe I'm now hijacking this topic. Need to make a new one?

 

Well for example:

PlayerInteractEvent extends Event

 

I definitely think it would be great to have a wiki page for this. I don't know how to make one, would someone else care to?

 

http://wiki.bukkit.org/Common_Coding_Etiquette

Done

Feel free to add stuff

 

your sly dog you

 

All of the Minecraft and Bukkit code are shockingly poor at memory management, compared to the kinds of lean optimizations you are expected to do in small systems and embedded software, like say Java-based Android applications.

Java's collection classes soak up memory like a sponge. You're relying on the garbage collector to do a good job of returning megabytes of memory to the pool every few seconds, and doing it without stuttering the CPU load on those opportunities. Tuning the server's garbage collector settings can only get you so far.

In addition to the above tips, when possible, use plain arrays of a fixed size, instead of the genericized Java collections. Recycle lightweight objects instead of just discarding them and making new ones. Understand an algorithm's "cyclometric complexity," which is fancy talk for how bad the worst case looping might be. Don't loop through a List to see if an item is in it; use a Set if you're interested in membership more often. Break up larger work loops into slices or strips, and do a little bit of work every few ticks, rather than all of the job in one tick.

 

That's actually java in general not just Minecraft and Bukkit.

 

Minecraft and, especially Bukkit are massive memory hogs in my expedience compared to all the other java libraries I've worked with.

 

Wow! A definite thanks for the all the input here so far, and a permanent wiki page sounds nice. I think calling it coding etiquette may be a little bit of a misrepresentation though... Etiquette sounds more like the 'polite' way of coding so that others can easily understand what your code does after a quick skim through, where as best practices tend to be ways to actually make your code more efficient. Just my two cents. :3

 

Ok,
I am new to Bukkit, but not new to JAVA,
so maybe we can discuss about some examples:

storage:
store are Object on a locale field or not?
If you need the object huge times, yes (dont forget to update the object)

How?
example: We want to change Blocks.
Mostly bad idea:

Code:

ArrayList<Blocks> myList;
[...]
for (...)
myList.add(block)

If you know the size of the Array, use:

Code:

Block[] betterBlockStorage = new Block[mysize];
for(...)
betterBlockStorage[i] = block;

Otherwise if you read >= add maybe it is a good idea to use Collections.toArray.
Did you need the whole Block-Object?
If you need only the int Coordinates of the Block use an int[][] array (or your own PlaceHolderObject).

Another point:

Code:

private Block[] betterBlockStorage;
[...]
if(betterBlockStorage  == null || betterBlockStorage .length != mysize) {
    betterBlockStorage = new Block[mysize];
for(...)
betterBlockStorage[i] = block;

PLEASE CORRECT ME !!!

btw,

PlayerManager, EntityManager, ... are not ObjectOriented, but necessary, is that your statement?

 

PlayerManager and EntityManager don't exist in Bukkit, I was explaining why.

 

Yes right,
but e.g. the NPCLibaries have a NPCManager and sometimes it is usefull
I would write some more stuff later^^

btw. we can open a thread that shows "good" coded plugins...