Making Data available to every class in a project.

[JOHNINALBANY]

I am new to java.

I have a java class (GetData) that imports and processes data from a database. This data is used by other classes in my program. The GetData class is invoked by the main class of my program.

In order to make these data available to every single class I am using the following approach: Every time an instance of a class is created, an instance of the GetData class is passed to the invoked class through the constructor.

Is this the right approach to accomplish this? Are there any other solutions?

I come from procedural programming where external variables can be used to accomplish this.Java does not have such a thing.

Thanks

[eRaaaa]

that`s right! but often it`s very hard to do that by hand so you could use dependency injection frameworks like google guice ,spring, ejb and so on.

[JOHNINALBANY]

<<you could use dependency injection frameworks like google guice ,spring, ejb and so on. >>

Could you clarify the above with an example?

[eRaaaa]

you will find examples on the homepages of the frameworks, e.g. here: Motivation - google-guice - Project Hosting on Google Code

but if you are new to java you should stay at your idea :)

[gcalvin]

If the data is read-only (sort of implied by the class name) then you might consider a Singleton pattern.

Singleton pattern - Wikipedia, the free encyclopedia

Basically, you create only one instance of the GetData object, and pass a reference to that one instance to all the classes that need it.

-Gary-

[Tolls]

You don't need to pass the reference, though, for a Singleton since any class should be able to access the MySingleton.getInstance() method.