Source for java.nio.charset.CoderResult

   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: }