Source for gnu.java.security.util.SimpleList

   1: /* SimpleList.java -- simple way to make tuples.
   2:    Copyright (C) 2004, 2006 Free Software Foundation, Inc.
   3: 
   4: This file is a 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 of the License, or (at
   9: your option) 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; if not, write to the Free Software
  18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  19: 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.java.security.util;
  40: 
  41: import java.util.AbstractList;
  42: import java.util.Collection;
  43: import java.util.Iterator;
  44: 
  45: /**
  46:  * A simple way to create immutable n-tuples. This class can be created with up
  47:  * to four elements specified via one of the constructors, or with a collection
  48:  * of arbitrary size.
  49:  */
  50: public final class SimpleList
  51:     extends AbstractList
  52: {
  53:   private final Object[] elements;
  54: 
  55:   /**
  56:    * Create a singleton list.
  57:    *
  58:    * @param element The first element.
  59:    */
  60:   public SimpleList(final Object element)
  61:   {
  62:     elements = new Object[1];
  63:     elements[0] = element;
  64:   }
  65: 
  66:   /**
  67:    * Create an ordered pair (2-tuple).
  68:    *
  69:    * @param e1 The first element.
  70:    * @param e2 The second element.
  71:    */
  72:   public SimpleList(final Object e1, final Object e2)
  73:   {
  74:     elements = new Object[2];
  75:     elements[0] = e1;
  76:     elements[1] = e2;
  77:   }
  78: 
  79:   /**
  80:    * Create a 3-tuple.
  81:    *
  82:    * @param e1 The first element.
  83:    * @param e2 The second element.
  84:    * @param e3 The third element.
  85:    */
  86:   public SimpleList(final Object e1, final Object e2, final Object e3)
  87:   {
  88:     elements = new Object[3];
  89:     elements[0] = e1;
  90:     elements[1] = e2;
  91:     elements[2] = e3;
  92:   }
  93: 
  94:   /**
  95:    * Create a 4-tuple.
  96:    *
  97:    * @param e1 The first element.
  98:    * @param e2 The second element.
  99:    * @param e3 The third element.
 100:    * @param e4 The fourth element.
 101:    */
 102:   public SimpleList(final Object e1, final Object e2, final Object e3,
 103:                     final Object e4)
 104:   {
 105:     elements = new Object[4];
 106:     elements[0] = e1;
 107:     elements[1] = e2;
 108:     elements[2] = e3;
 109:     elements[3] = e4;
 110:   }
 111: 
 112:   /**
 113:    * Create the empty list.
 114:    */
 115:   public SimpleList()
 116:   {
 117:     elements = null;
 118:   }
 119: 
 120:   /**
 121:    * Create an n-tuple of arbitrary size. Even if the supplied collection has no
 122:    * natural order, the created n-tuple will have the order that the elements
 123:    * are returned by the collection's iterator.
 124:    *
 125:    * @param c The collection.
 126:    */
 127:   public SimpleList(Collection c)
 128:   {
 129:     elements = new Object[c.size()];
 130:     int i = 0;
 131:     for (Iterator it = c.iterator(); it.hasNext() && i < elements.length;)
 132:       elements[i++] = it.next();
 133:   }
 134: 
 135:   public int size()
 136:   {
 137:     if (elements == null)
 138:       return 0;
 139:     return elements.length;
 140:   }
 141: 
 142:   public Object get(int index)
 143:   {
 144:     if (elements == null)
 145:       throw new IndexOutOfBoundsException("list is empty");
 146:     if (index < 0 || index >= elements.length)
 147:       throw new IndexOutOfBoundsException("index=" + index + ", size=" + size());
 148:     return elements[index];
 149:   }
 150: 
 151:   public String toString()
 152:   {
 153:     return SimpleList.class.getName() + "(" + size() + ") " + super.toString();
 154:   }
 155: }