001    /* CoderResult.java --
002       Copyright (C) 2002, 2004 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    package java.nio.charset;
039    
040    import java.lang.ref.WeakReference;
041    import java.nio.BufferOverflowException;
042    import java.nio.BufferUnderflowException;
043    import java.util.HashMap;
044    
045    /**
046     * @author Jesse Rosenstock
047     * @since 1.4
048     */
049    public class CoderResult
050    {
051      private static final int TYPE_MALFORMED  = 0;
052      private static final int TYPE_OVERFLOW   = 1;
053      private static final int TYPE_UNDERFLOW  = 2;
054      private static final int TYPE_UNMAPPABLE = 3;
055    
056      public static final CoderResult OVERFLOW
057        = new CoderResult (TYPE_OVERFLOW, 0);
058      public static final CoderResult UNDERFLOW
059        = new CoderResult (TYPE_UNDERFLOW, 0);
060    
061      private static final String[] names
062        = { "MALFORMED", "OVERFLOW", "UNDERFLOW", "UNMAPPABLE" };
063    
064      private static final Cache malformedCache
065        = new Cache ()
066          {
067            protected CoderResult make (int length)
068            {
069              return new CoderResult (TYPE_MALFORMED, length);
070            }
071          };
072    
073      private static final Cache unmappableCache
074        = new Cache ()
075          {
076            protected CoderResult make (int length)
077            {
078              return new CoderResult (TYPE_UNMAPPABLE, length);
079            }
080          };
081    
082      private final int type;
083      private final int length;
084    
085      // Package-private to avoid a trampoline constructor.
086      CoderResult (int type, int length)
087      {
088        this.type = type;
089        this.length = length;
090      }
091    
092      public boolean isError ()
093      {
094        return length > 0;
095      }
096    
097      public boolean isMalformed ()
098      {
099        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 = Integer.valueOf (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    }