gomp-20050608-branch/libjava/classpath/java/nio/charset/CoderResult.java

   1 /* CoderResult.java --
   2    Copyright (C) 2002, 2004 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 package java.nio.charset;
  39
  40 import java.lang.ref.WeakReference;
  41 import java.nio.BufferOverflowException;
  42 import java.nio.BufferUnderflowException;
  43 import java.util.HashMap;
  44
  45 /**
  46  * @author Jesse Rosenstock
  47  * @since 1.4
  48  */
  49 public class CoderResult
  50 {
  51   private static final int TYPE_MALFORMED  = 0;
  52   private static final int TYPE_OVERFLOW   = 1;
  53   private static final int TYPE_UNDERFLOW  = 2;
  54   private static final int TYPE_UNMAPPABLE = 3;
  55
  56   public static final CoderResult OVERFLOW
  57     = new CoderResult (TYPE_OVERFLOW, 0);
  58   public static final CoderResult UNDERFLOW
  59     = new CoderResult (TYPE_UNDERFLOW, 0);
  60
  61   private static final String[] names
  62     = { "MALFORMED", "OVERFLOW", "UNDERFLOW", "UNMAPPABLE" };
  63
  64   private static final Cache malformedCache
  65     = new Cache ()
  66       {
  67         protected CoderResult make (int length)
  68         {
  69           return new CoderResult (TYPE_MALFORMED, length);
  70         }
  71       };
  72
  73   private static final Cache unmappableCache
  74     = new Cache ()
  75       {
  76         protected CoderResult make (int length)
  77         {
  78           return new CoderResult (TYPE_UNMAPPABLE, length);
  79         }
  80       };
  81
  82   private final int type;
  83   private final int length;
  84
  85   // Package-private to avoid a trampoline constructor.
  86   CoderResult (int type, int length)
  87   {
  88     this.type = type;
  89     this.length = length;
  90   }
  91
  92   public boolean isError ()
  93   {
  94     return length > 0;
  95   }
  96
  97   public boolean isMalformed ()
  98   {
  99     return type == TYPE_MALFORMED;
 100   }
 101
 102   public boolean isOverflow ()
 103   {
 104     return type == TYPE_OVERFLOW;
 105   }
 106
 107   public boolean isUnderflow ()
 108   {
 109     return type == TYPE_UNDERFLOW;
 110   }
 111
 112   public boolean isUnmappable ()
 113   {
 114     return type == TYPE_UNMAPPABLE;
 115   }
 116
 117   public int length ()
 118   {
 119     if (length <= 0)
 120       throw new UnsupportedOperationException ();
 121     else
 122       return length;
 123   }
 124
 125   public static CoderResult malformedForLength (int length)
 126   {
 127     return malformedCache.get (length);
 128   }
 129
 130   public void throwException ()
 131     throws CharacterCodingException
 132   {
 133     switch (type)
 134       {
 135         case TYPE_MALFORMED:
 136           throw new MalformedInputException (length);
 137         case TYPE_OVERFLOW:
 138           throw new BufferOverflowException ();
 139         case TYPE_UNDERFLOW:
 140           throw new BufferUnderflowException ();
 141         case TYPE_UNMAPPABLE:
 142           throw new UnmappableCharacterException (length);
 143       }
 144   }
 145
 146   public String toString ()
 147   {
 148     String name = names[type];
 149     return (length > 0) ? name + '[' + length + ']' : name;
 150   }
 151
 152   public static CoderResult unmappableForLength (int length)
 153   {
 154     return unmappableCache.get (length);
 155   }
 156
 157   private abstract static class Cache
 158   {
 159     private final HashMap cache;
 160
 161     // Package-private to avoid a trampoline constructor.
 162     Cache ()
 163     {
 164       cache = new HashMap ();
 165     }
 166
 167     // Package-private to avoid a trampoline.
 168     synchronized CoderResult get (int length)
 169     {
 170       if (length <= 0)
 171         throw new IllegalArgumentException ("Non-positive length");
 172
 173       Integer len = new Integer (length);
 174       CoderResult cr = null;
 175       Object o;
 176       if ((o = cache.get (len)) != null)
 177         cr = (CoderResult) ((WeakReference) o).get ();
 178       if (cr == null)
 179         {
 180           cr = make (length);
 181           cache.put (len, new WeakReference (cr));
 182         }
 183
 184       return cr;
 185     }
 186
 187     protected abstract CoderResult make (int length);
 188   }
 189 }