Determining if an Object is of primitive type
The types in an Object[]
will never really be primitive - because you've got references! Here the type of i
is int
whereas the type of the object referenced by o
is Integer
(due to auto-boxing).
It sounds like you need to find out whether the type is a "wrapper for primitive". I don't think there's anything built into the standard libraries for this, but it's easy to code up:
import java.util.*;
public class Test
{
public static void main(String[] args)
{
System.out.println(isWrapperType(String.class));
System.out.println(isWrapperType(Integer.class));
}
private static final Set<Class<?>> WRAPPER_TYPES = getWrapperTypes();
public static boolean isWrapperType(Class<?> clazz)
{
return WRAPPER_TYPES.contains(clazz);
}
private static Set<Class<?>> getWrapperTypes()
{
Set<Class<?>> ret = new HashSet<Class<?>>();
ret.add(Boolean.class);
ret.add(Character.class);
ret.add(Byte.class);
ret.add(Short.class);
ret.add(Integer.class);
ret.add(Long.class);
ret.add(Float.class);
ret.add(Double.class);
ret.add(Void.class);
return ret;
}
}
commons-lang ClassUtils
has relevant methods.
The new version has:
boolean isPrimitiveOrWrapped =
ClassUtils.isPrimitiveOrWrapper(object.getClass());
The old versions have wrapperToPrimitive(clazz)
method, which will return the primitive correspondence.
boolean isPrimitiveOrWrapped =
clazz.isPrimitive() || ClassUtils.wrapperToPrimitive(clazz) != null;