harmony-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jimmy,Jing Lv" <firep...@gmail.com>
Subject Re: [classlib][lang] Is it possible to new an object without invoking any constructor?
Date Thu, 15 Nov 2007 06:31:20 GMT
2007/11/15, Andrew Zhang <zhanghuangzhu@gmail.com>:
> On Nov 15, 2007 1:22 PM, Jimmy,Jing Lv <firepure@gmail.com> wrote:
>
> > A simple thought is using the JNI call AllocObject(JNIEnv *env, jclass
> > clazz);
> > however we need to implement a native api then :)
> >
>
> Thanks Jimmy!
>

:)

> AllocObject looks like what I want. ObjectInputStream#newInstance is even
> closer (it has defined a native method). Is it possible to refactor?
> Comments? Thanks!
>

Hmm, it seems the current native method newInstance is used for
ObjectInputStream itself, so refactor it may not be a good idea (will
surely break Harmony function) . I suggest define it in some utility
class or your own class :)

> Java_java_io_ObjectInputStream_newInstance (JNIEnv * env, jclass clazz,
>                                             jobject instantiationClass,
>                                             jobject constructorClass)
> {
>   jmethodID mid =
>     (*env)->GetMethodID (env, constructorClass, "<init>", "()V");
>
>   if (mid == 0)
>     {
>       /* Cant newInstance,No empty constructor... */
>       return (jobject) 0;
>     }
>   else
>     {
>       /* Instantiate an object of a given class and constuct it using
>          the constructor of the other class. */
>       jobject obj;
>       obj = (*env)->AllocObject(env, instantiationClass);  // I want this
> method :)
>       if (obj != NULL) {
>         (*env)->CallNonvirtualVoidMethod(env, obj, constructorClass, mid);
>       }
>       return obj;
>     }
>
> }
>
>
> > 2007/11/15, Andrew Zhang <zhanghuangzhu@gmail.com>:
> > > Hi,
> > >
> > > Is it possible to new an object without invoking any constructor? I know
> > the
> > > question is a bit weird. What I want is to create an object with all
> > > null/default value for its fields.
> > > Reseting all fields to null by reflection is a possible solution, but is
> > > there any existing special method (no matter it's low level or Harmony
> > > specific) which can achieve this goal?
> > > Thanks!
> > >
> > >
> > > --
> > > Best regards,
> > > Andrew Zhang
> > >
> > > http://zhanghuangzhu.blogspot.com/
> > >
> >
> >
> > --
> >
> > Best Regards!
> >
> > Jimmy, Jing Lv
> > China Software Development Lab, IBM
> >
>
>
>
> --
> Best regards,
> Andrew Zhang
>
> http://zhanghuangzhu.blogspot.com/
>


-- 

Best Regards!

Jimmy, Jing Lv
China Software Development Lab, IBM

Mime
View raw message