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 }