[Nice-commit] Nice/stdlib/nice/lang/reflect promotion-demotion.nice,NONE,1.1 instances.nice,1.2,1.3

[Daniel B. <bo...@us...>]

Update of /cvsroot/nice/Nice/stdlib/nice/lang/reflect
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv6432/stdlib/nice/lang/reflect

Modified Files:
	instances.nice 
Added Files:
	promotion-demotion.nice 
Log Message:
java.lang.Class is now parameterized by the type it represents.


--- NEW FILE: promotion-demotion.nice ---
/**************************************************************************/
/*                                N I C E                                 */
/*             A high-level object-oriented research language             */
/*                        (c) Daniel Bonniot 2004                         */
/*                                                                        */
/*  This program is free software; you can redistribute it and/or modify  */
/*  it under the terms of the GNU General Public License as published by  */
/*  the Free Software Foundation; either version 2 of the License, or     */
/*  (at your option) any later version.                                   */
/*                                                                        */
/**************************************************************************/

package nice.lang.reflect;

/**
   @param source an object of type T
   @param target the Class of type U, a supertype of T
   @return a new instance of class U, keeping all relevant fields
           from object <code>source</code>
*/
public
<T, U | T <: U>
U demote(T source, Class<U> target)
{
  // Create the new object
  U res = target.newInstance();

  for (field : target.getFields())
    println(""field[res]" => "field[source]);

  // Initialize all fields of the new object by copy from the source
  for (field : target.getFields())
    field[res] = field[source];

  return res;
}

/**
   @param source an object of non-null type T
   @param target the Class of type U, a subtype of T
   @return a new instance of class U, keeping all fields
           from object <code>source</code>
*/
public
<!T, U | U <: T>
U promote(T source, Class<U> target)
{
  Class<T> sourceClass = source.getClass();

  U res = target.newInstance();

  for (field : target.getFields())
    {
      // Only copy fields that exist in the source class
      if (field.getDeclaringClass().isAssignableFrom(sourceClass))
	field[res] = field[source];
    }

  return res;
}

// Unit tests

class _Dog
{
  String name = "";
}

class _Dalmatian extends _Dog
{
  boolean spotted = false;
}

class _Chihuahua extends _Dog
{
  boolean dancing = false;
}

void _testDemote()
{
  _Dalmatian dalmatian = new _Dalmatian(name: "Dalmatian", spotted: true);
  _Dog dog = dalmatian.demote(nice.lang.reflect._Dog);
  assert dog.getClass() == nice.lang.reflect._Dog;
  assert dog.name.equals("Dalmatian");

  Object o = dog.demote(Object.class);

  // Error detected at compile time:
  //String s = dog.demote(java.lang.String);
}

void _testPromote()
{
  _Dog dog = new _Dog(name: "Simple dog");
  _Dalmatian dalmatian = dog.promote(nice.lang.reflect._Dalmatian);
  assert dalmatian.getClass() == nice.lang.reflect._Dalmatian;
  assert dalmatian.name.equals("Simple dog");
  assert ! dalmatian.spotted;

  _Chihuahua chihuahua = new _Chihuahua(name: "Chichi", dancing: true);
  dalmatian = chihuahua.promote(nice.lang.reflect._Dalmatian);
  assert dalmatian.getClass() == nice.lang.reflect._Dalmatian;
  assert dalmatian.name.equals("Chichi");
  assert ! dalmatian.spotted;
}

Index: instances.nice
===================================================================
RCS file: /cvsroot/nice/Nice/stdlib/nice/lang/reflect/instances.nice,v
retrieving revision 1.2
retrieving revision 1.3
diff -C2 -d -r1.2 -r1.3
*** instances.nice	12 Dec 2003 12:55:25 -0000	1.2
--- instances.nice	30 Jul 2004 19:08:42 -0000	1.3
***************
*** 52,59 ****
   ****************************************************************/
  
- public <T> T newInstance(Class) = native Object Class.newInstance();
- 
  public <T> T newInstance(String className) =
!   newInstance(Class.forName(className));
  
  // Testcases
--- 52,57 ----
   ****************************************************************/
  
  public <T> T newInstance(String className) =
!   cast(newInstance(Class.forName(className)));
  
  // Testcases