Question

I’m working on a programming lanuage, i need to convert an object (like var in javascript) in to the type of variable it should be. Ex:

if(object == variabletypes.string)
{
//convert object to string
}
else if(object ==variabletypes.int)
{
//convert to integer
}

Thanks for your time, any help would be appreciated.

Answer 1

Assuming you’ve got a java.lang.Object, this is a start:

Object o = /* ??? */;
if (o instanceof String)
{
    String s = (String) o;
}
else if (o instanceof Integer)
{
    Integer integer = (Integer) o;
    int i = integer.intValue();
}

The “conversion” here is primarily casting, operating under the assumption that the object already has the correct runtime type, and that you don’t need to actually alter the internal representation — for instance, by changing a String to an int with Integer#parseInt().

Other potentially useful methods (since the question isn’t exactly clear) may include:

• Object#getClass()
• Class#cast(Object)
• Class#isAssignableFrom(Class)