Source for gnu.CORBA.NamingService.NameComponentComparator

   1: /* NameComponentComparator.java --
   2:    Copyright (C) 2005 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package gnu.CORBA.NamingService;
  40: 
  41: import org.omg.CORBA.BAD_PARAM;
  42: import org.omg.CosNaming.NameComponent;
  43: 
  44: import java.util.Comparator;
  45: 
  46: /**
  47:  * This class implements the name component comparator, needed to
  48:  * sort and compare the name components in maps and sorted sets.
  49:  *
  50:  * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
  51:  */
  52: public final class NameComponentComparator
  53:   implements Comparator
  54: {
  55:   /**
  56:    * The singleton instance of the name comparator.
  57:    */
  58:   public static final NameComponentComparator singleton = new NameComponentComparator();
  59: 
  60:   /**
  61:    * It is enough to have a singleton.
  62:    */
  63:   private NameComponentComparator()
  64:   {
  65:   }
  66: 
  67:   /**
  68:    * Compare the two names components.
  69:    *
  70:    * @param nc_a the first name component.
  71:    * @param nc_b the second name component.
  72:    *
  73:    * @return 0 if the name components are equal, non zero value
  74:    * as result of comparison otherwise.
  75:    *
  76:    * @throws BAD_PARAM if one of the components is empty or
  77:    * has {@link NameComponent#id} or {@link NameComponent#kind}
  78:    * field intialised to null.
  79:    */
  80:   public final int compare(Object nc_a, Object nc_b)
  81:   {
  82:     NameComponent a = (NameComponent) nc_a;
  83:     NameComponent b = (NameComponent) nc_b;
  84: 
  85:     int cn = a.id.compareTo(b.id);
  86:     if (cn != 0)
  87:       return cn;
  88:     return a.kind.compareTo(b.kind);
  89:   }
  90: 
  91:   /**
  92:    * All instances of this class are equal.
  93:    */
  94:   public boolean equals(Object x)
  95:   {
  96:     return x instanceof NameComponentComparator;
  97:   }
  98: }