Re: when will Tuple be std?

Eric Sosman <esosman@ieee-dot-org.invalid> writes:


  Sometimes, one wants to handle (e.g., compare) pairs in the
  sense, that two pairs are equal if both components are, and
  one does /not/ want to write a custom class each time but
  reuse a common tuple class, because one does not need more
  methods beyond those for comparison.

  For example, my library

http://www.purl.org/stefan_ram/pub/ram-jar

  has a ?comparable tuple? class, so one can execute the
  following program.

public class Main
{

  /** A convenience method to construct a tuple. */
  static de.dclj.ram.type.tuple.ComparableTuple
  <de.dclj.ram.type.tuple.DefaultComparableTuple>
  tuple( java.lang.Comparable ... args ) { return new
    de.dclj.ram.type.tuple.DefaultComparableTuple( args ); }

  final static java.lang.String nl =
  java.lang.System.getProperty( "line.separator" );
  
  public static void main( final java.lang.String[] args )
  {
    java.lang.System.out.println
    ( tuple( 12000, "beta" ).hashCode() + nl +
      tuple( 12000, "beta" ).hashCode() + nl +
      tuple( 12001, "beta" ).hashCode() + nl +
      tuple( 12000, "betb" ).hashCode() + nl +
      tuple( 12000, "beta" ).equals( tuple( 12000, "beta" )) + nl +
      tuple( 12000, "beta" ).equals( tuple( 12001, "beta" )) + nl +
      tuple( 12000, "beta" ).equals( tuple( 12000, "betb" )) + nl );

    final java.util.List<de.dclj.ram.type.tuple.ComparableTuple> list
    = new java.util.ArrayList<de.dclj.ram.type.tuple.ComparableTuple>();
    list.add( tuple( 12000, "gamma" ));
    list.add( tuple( 10000, "alpha" ));
    list.add( tuple( 20000, "delta" ));
    list.add( tuple( 12000, "beta" ));
    java.util.Collections.sort( list );
    java.lang.System.out.println( list ); }}

3029778
3029778
3029779
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true
false
false

[( 10000; "alpha" ), ( 12000; "beta" ), ( 12000; "gamma" ), ( 20000; "delta" )]

  With Java SE, a good approximation is to use an array and the
  static ?hashCode? and ?equals? methods from java.util.Arrays.