WolfmanDragon WolfmanDragon - 2 months ago 7
Java Question

How do I find out what type each object is in a ArrayList<Object>?

I have a ArrayList made up of different elements imported from a db, made up of strings, numbers, doubles and ints. Is there a way to use a reflection type technique to find out what each type of data each element holds?

FYI: The reason that there is so many types of data is that this is a piece of java code being written to be implemented with different DB's.

Answer

In C#:
Fixed with recommendation from Mike

ArrayList list = ...;
// List<object> list = ...;
foreach (object o in list) {
    if (o is int) {
        HandleInt((int)o);
    }
    else if (o is string) {
        HandleString((string)o);
    }
    ...
}

In Java:

ArrayList<Object> list = ...;
for (Object o : list) {
    if (o instanceof Integer)) {
        handleInt((int)o);
    }
    else if (o instanceof String)) {
        handleString((String)o);
    }
    ...
}