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Java Solutions August 2001/import java.*/Listing 6

Listing 6: ObjectInspector.java — Prints all accessible fields in an object

import java.lang.reflect.*;

class ObjectInspector
{
   public static void inspect(Object o)
      throws IllegalAccessException
   {
      // Get class and fields for object
      Class c = o.getClass();

      while (c != Object.class)
      {
         System.out.println("// Fields in " + c);
         Field[] fields = c.getDeclaredFields();
         AccessibleObject.setAccessible(fields, true);
   
         // Print field values
         for (int i = 0; i < fields.length; ++i)
         {
            Field fld = fields[i];
            System.out.print(fld.getName() + ": ");
            System.out.println(fld.get(o));
         }
         System.out.println();
         c = c.getSuperclass();
      }
   }

   public static void main(String[] args)
   {
      try
      {
         inspect(new java.util.TreeMap());
      }
      catch (IllegalAccessException x)
      {
         System.out.println(x);
      }
   }
}

/* Output:
// Fields in class java.util.TreeMap
comparator: null
root: null
size: 0
modCount: 0
keySet: null
entrySet: null
values: null
KEYS: 0
VALUES: 1
ENTRIES: 2
RED: false
BLACK: true
serialVersionUID: 919286545866124006

// Fields in class java.util.AbstractMap
keySet: null
values: null

*/
— End of Listing —

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