// This example is from _Java Examples in a Nutshell_. (http://www.oreilly.com)
// Copyright (c) 1997 by David Flanagan
// This example is provided WITHOUT ANY WARRANTY either expressed or implied.
// You may study, use, modify, and distribute it for non-commercial purposes.
// For any commercial use, see http://www.davidflanagan.com/javaexamples
import java.lang.reflect.*;


/** 
 *  A program that displays a class synopsis for the named class
 */
public class ShowClass
{
  /**
   *  The main method.  Print info about the named class
   */
  public static void main (String[] args)
      throws ClassNotFoundException
  {
      Class c = Class.forName(args[0]);
      print_class(c);
  }

  /** 
   *  Display the modifiers, name, superclass and interfaces of a
   *  class or interface. Then go and list all constructors, fields,
   *  and methods.
   */
  public static void print_class (Class c)
  {
      // Print modifiers, type (class or interface), name and superclass.
      if (c.isInterface())
      {
	  // The modifiers will include the "interface" keyword here...
	  System.out.print(Modifier.toString(c.getModifiers()) + 
			   " " +
			   c.getName());
      }
      else
      {
	  System.out.print(Modifier.toString(c.getModifiers()) + 
			   " class " +
			   c.getName());
	  if (c.getSuperclass() != null)
	  {
	      System.out.print(" extends " + c.getSuperclass().getName());
	  }
      }

      // Print interfaces or super-interfaces of the class or interface.
      Class[] interfaces = c.getInterfaces();
      if ((interfaces != null) && (interfaces.length > 0))
      {
	  if (c.isInterface()) System.out.println(" extends ");
	  else System.out.print(" implements ");
	  for (int i = 0; i < interfaces.length; i++)
	  {
	      if (i > 0) System.out.print(", ");
	      System.out.print(interfaces[i].getName());
	  }
      }

      System.out.println(" {");            // Begin class member listing.

      // Now look up and display the members of the class.
      System.out.println(" // Constructors");
      Constructor[] constructors = c.getDeclaredConstructors();
      for(int i = 0; i < constructors.length; i++)
      {
	  print_method_or_constructor(constructors[i]);
      }

      System.out.println(" // Fields");
      Field[] fields = c.getDeclaredFields();
      for(int i = 0; i < fields.length; i++)
      {
	  print_field(fields[i]);
      }

      System.out.println(" // Methods");
      Method[] methods = c.getDeclaredMethods();
      for(int i = 0; i < methods.length; i++)
      {
	  print_method_or_constructor(methods[i]);
      }

      System.out.println("}");             // End class member listing.
  }

  /**
   *  Return the name of an interface or primitive type, handling
   *  arrays.
   */
  public static String typename (Class t)
  {
      String brackets = "";
      while (t.isArray())
      {
	  brackets += "[]";
	  t = t.getComponentType();
      }
      return t.getName() + brackets;
  }

  /**
   *  Return a string version of modifiers, handling spaces nicely.
   */
  public static String modifiers (int m)
  {
      if (m == 0) return "";
      else        return Modifier.toString(m) + " ";
  }

  /** Print the modifiers, type, and name of a field */
  public static void print_field(Field f) {
    System.out.println("  " +
                       modifiers(f.getModifiers()) +
                       typename(f.getType()) + " " + f.getName() + ";");
  }

  /**
   *  Print the modifiers, return type, name, parameter types and
   *  exception type of a method or constructor.  Note the use of the
   *  Member interface to allow this method to work with both Method
   *  and Constructor objects
   */
  public static void print_method_or_constructor (Member member)
  {
      Class returntype = null, parameters[], exceptions[];
      if (member instanceof Method)
      {
	  Method m = (Method) member;
	  returntype = m.getReturnType();
	  parameters = m.getParameterTypes();
	  exceptions = m.getExceptionTypes();
      }
      else
      {
	  Constructor c = (Constructor) member;
	  parameters = c.getParameterTypes();
	  exceptions = c.getExceptionTypes();
      }

      System.out.print("  " + modifiers(member.getModifiers()) +
		       ((returntype != null)? typename(returntype) + " " : "") +
		       member.getName() + "(");
      for (int i = 0; i < parameters.length; i++)
      {
	  if (i > 0) System.out.print(", ");
	  System.out.print(typename(parameters[i]));
      }
      System.out.print(")");
      if (exceptions.length > 0) System.out.print(" throws ");
      for(int i = 0; i < exceptions.length; i++)
      {
	  if (i > 0) System.out.print(", ");
	  System.out.print(typename(exceptions[i]));
      }
      System.out.println(";");
  }
}