Axis2 How to create a service instance for other services - service

Question

My service will load a lot of data (from txt files) to memory every request.
But,I want to keep the data in memory.
Because it is read from same txt files.
public class pirTMain {
public String[] RUN_pirT(...){
...
//this object will read txt files to initialize
ELC elc = new ELC(elcFolder.getPath());
//use elc to initialize a graph
pirT.initGraph(userID, nodeFile.getPath(), userScore, elc, true, begin, target);
//Use graph to search paths
itinerary = pirT.search(userID, TopK, begin, beginWithTime, target, targetWithTime);
...
I had read Axis2 document.
It says I can change service scope to "application".
But I still don't know how to do it, because I use eclipse plugin to generate a web service *.arr.
Can anyone suggest me how to separate elc object to another service?
Then, my pirTMain class can use it.
pirTMain is 'request'.
elc is 'application'.
thanks a lot.

Answer 1

There are a lot of different ways to achieve this, the simplest one that comes in my mind is to create a static reference to the read lines so that it's shared among all threads in the same virtual machine:
#WebService
public MyServiceClass {
private static String[] readLines = null;
private static synchronized getLines(){
if (readLines == null)
readLines = ....;
return readLines;
}
public int getNumberOfLines(){
return MyServiceClass.getLines().length;
}
public String getLine(int position){
return MyServiceClass.getLines()[position];
}
...
}
Probably not the "cleanest" way, but it works and it's easy to do. You could also wrap the login in a more standard "singleton pattern" if you prefer. keep in mind that getLines should be synchronized to be thread safe but if you experience bottlenecks remove the synchronized keyword, you could get useless reads on first calls but it would be faster.