On Tue, 3 Jun 2003, Inglima Modica Davide Silvio wrote:
> Modifiers and ids -- K - 2003 03 18
> 1) Modifiers: "Modifiers" means the way I chose to apply changes to
> entities in the game. That changes could be temporary ("transient") or
> can be not-reversible ("permanent").
[snip]
The problem is: what do you think a modifier has to do?
* Does it have to work as a netbeans/eclipse/mozilla plugin component?
* Does it have instead to work a simple "modifier" for the outcome of an
action?
In the first case the chaos ensues, but in the second case it is
rather simple.
You have a modifier which:
(a) registers (enters a stack)
(b) unregisters
let's say to have a man with "Strenght" as one of his characteristics,
then there is a stack of modifiers somewhere.
To get the raw or modified strenght we have these member functions:
int getStrenghtRaw() {
return strenght;
}
int getStrenghtModified() {
int tempvalue = processStrenght(strengh);
return validate(tempvalue);
}
To add a modifier we use a Collection:
List strenghtPile;
void strenghtModifiersPile(StrenghtModifier x) {
/// should throw an exception in case of duplicate modifier
strenghtPile.add(x);
}
To use the modifiers then we iterate on it:
int processStrenght(int strenght) {
/// of course it could access directly strenght, but maybe we want
/// a little more freedom...
/*
* insert classic iterator example here
* since I'm trying to remember things...
*/
Iterator i = strenghtPile.getIterator()
while(i.hasnext()) {
strenght = i.getNext().getModifierAction(strenght);
}
return strenght;
}
Modifiers then could be added or removed when needed
> We need a way to identify the modifier to remove.
> [ADD] I need some explanation: how the universe is supposed to
> work? The "universe" has many "worlds" (one per runtime environment)
> connected, and an entity can travel from one to another
> on the net (ie over TCP/IP, etc.)? [ADD]
[snip]
> 3.1) What can be used as id in Java?
[snip]
> [ADD] 4- java.rmi.server.UID [ADD]
Could be useful (the classes you propose are in J2SE if I'm correct,
right?).
Anyway...
IDManager could be a singleton class.
A singleton is a design pattern which says: "for each running instance of
program x there is only a given object of a given singleton class", so
having only one IDManager we can keep track of consistencies and
inconsistencies.
If we ever need to have a set of local and distributed IDManagers, the
local IDManager could call a central server IDManager which will give back
a pool of 100/1000 id's at a time.
How to write a singleton:
package net.sourceforge.avatars.util;
public class IDManager {
private static IDManager idmanager = null;
private int lastid = 0;
// note the private constructor
private IDManager() {
}
// this creates a new IDManager OR returns the IDManager already running
public static IDManager getInstance() {
if (idmanager == null) {
idmanager = new IDManager();
}
return idmanager;
}
// this returns a number and adds one to the count;
public synchronized Integer getNewID() {
Integer result = new Integer(lastid);
lastid++;
return result;
}
}
How to access it:
IDManager idm = IDManager.getInstance();
Integer ix = idm.getNewID();
If we need to scale the IDs to a number higher, we could give back
a class with four integers, or whatevere other else.
Do we really need to free the IDs after having used them?
Ciao.
--
Davide Silvio Inglima-Modica
"Mana is rapidly disappearing from the world, Even the"
"mana tree has begun to wither" - Seiken Densetsu 3
http://web.tiscali.it/inglima/davide/
mailto:had...@li...
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