I use the following trick to get the array type of a specific class:
@SuppressWarnings("unchecked")
public static <T> Class<T[]> getArrayType(Class<T> componentType) {
String arrayClassName = "[L" + componentType.getName() + ";";
try {
return (Class<T[]>) Class.forName(arrayClassName);
} catch (ClassNotFoundException e) {
throw new UnexpectedException("Can't get the array type for " + componentType, e);
}
}
But, is there any more elegant way to get this?
Perhaps using Array.newInstance(), which returns an array of a given type.
Doing something like:
return Array.newInstance(someClass, 0).getClass()
Might get you what you want.
Hope that helps.
I would do the same as Zach L but memoize the result:
import java.lang.reflect.Array;
import java.util.concurrent.ConcurrentMap;
import com.google.common.base.Function;
import com.google.common.collect.MapMaker;
// ...
static Function<Class<?>, Class<?>> TO_ARRAY_FUNC =
new Function<Class<?>, Class<?>>() {
@Override
public Class<?> apply(Class<?> from) {
return Array.newInstance(from, 0).getClass();
}
};
static ConcurrentMap<Class<?>, Class<?>> ARRAY_TYPE_MAP =
new MapMaker().weakKeys()
.weakValues()
.makeComputingMap(TO_ARRAY_FUNC);
@SuppressWarnings("unchecked")
public static <T>Class<T[]> getArrayType(Class<T> componentType) {
return (Class<T[]>) ARRAY_TYPE_MAP.get(componentType);
}
Try this:
@SuppressWarnings({"unchecked"})
public static <T> Class<T[]> getArrayType(Class<T> componentType) {
return (Class<T[]>) Array.newInstance(componentType, 1).getClass();
}
You can't escape the warning but it is shorter and better.
