В простейшем случае это выглядит так:
| Код | public static Object clone(Object orig) throws IllegalAccessException, InstantiationException
{
if(orig == null)
return null;
Class clazz = orig.getClass();
if(isImmutableOrPrimitive(clazz))
return orig;
Object copy = clazz.newInstance();
while(clazz != Object.class && clazz != null)
{
copyFields(clazz.getDeclaredFields(), orig, copy);
clazz = clazz.getSuperclass();
}
return copy;
}
private static void copyFields(Field[] fields, Object source, Object target) throws IllegalAccessException, InstantiationException
{
for(Field field : fields)
{
if(Modifier.isStatic(field.getModifiers()))
continue;
if(Modifier.isFinal(field.getModifiers()))
{
System.err.println("final field[" + field + "] found at " + source.getClass() + ", skipped");
continue;
}
field.setAccessible(true);
Class fieldType = field.getType();
if(isImmutableOrPrimitive(fieldType))
{
Object val = field.get(source);
field.set(target, val);
}
else if(fieldType.isArray())
{
Class componentType = fieldType.getComponentType();
Object sourceArray = field.get(source);
int len = Array.getLength(sourceArray);
Object targetArray = Array.newInstance(componentType, len);
for(int i = 0; i < len; i++)
{
Object val = Array.get(sourceArray, i);
val = clone(val);
Array.set(targetArray, i, val);
}
field.set(target, targetArray);
}
else
{
Object val = field.get(source);
val = clone(val);
field.set(target, val);
}
}
}
private static boolean isImmutableOrPrimitive(Class clazz)
{
return clazz.isPrimitive() ||
clazz.isEnum() ||
clazz == String.class ||
clazz == Boolean.class ||
clazz == Character.class ||
clazz == Long.class ||
clazz == Integer.class ||
clazz == Short.class ||
clazz == Byte.class ||
clazz == Double.class ||
clazz == Float.class ||
clazz == Void.class;
}
|
| Код | ArrayList<Object> list = new ArrayList<Object>();
list.add(new Date());
list.add("Some string");
list.add(33);
list.add(new Dimension(10, 10));
ArrayList<String> sublist = new ArrayList<String>();
for(int i = 0; i < 3; i++)
sublist.add(Integer.toString(i + 1));
list.add(sublist);
Object newList = clone(list);
System.out.println("list = " + list);
System.out.println("newList = " + newList); |
|
)
. 