Re: [Switch()...case]From String to enum

Daniel Moyne <dmoyne@tiscali.fr> writes:


  One might want to write:

switch( args[ 0 ])
{ case "alpha":
  System.out.println( "alpha" );
  break;
  case "gamma":
  System.out.println( "gamma" );
  break; }

  If it is known, that ?args[ 0 ]? always is either
  ?alpha? or ?gamma?:

switch( args[ 0 ].charAt( 0 ))
{ case 'a':
  System.out.println( "alpha" );
  break;
  case 'g':
  System.out.println( "gamma" );
  break; }

  One also sometimes can switch on a hash code of
  the string, or even a perfect hash code.

  Otherwise, a possible emulation is:

class Switch
{ final java.util.Map<String,Runnable> me;
  Switch( final Object ... args )
  { me = new java.util.HashMap<String,Runnable>();
    for( int i = 0; i < args.length; i += 2 )
    me.put(( String )args[ i ],( Runnable )args[ i + 1 ]); }
  void by( final String text ){ me.get( text ).run(); }}

public class Main
{ public static void main( final String[] args )
  { new Switch
    ( "alpha", new Runnable(){ public void run()
        { System.out.println( "alpha" ); }},
      "gamma", new Runnable(){ public void run()
        { System.out.println( "gamma" ); }}).
    by( args[ 0 ]); }}