Robust/src/Tests/ssJava/mp3decoder/JavaLayerUtils.java

   1 /*\r
   2  * 11/19/04             1.0 moved to LGPL.\r
   3  * 12/12/99             Initial version.        mdm@techie.com\r
   4  *-----------------------------------------------------------------------\r
   5  *   This program is free software; you can redistribute it and/or modify\r
   6  *   it under the terms of the GNU Library General Public License as published\r
   7  *   by the Free Software Foundation; either version 2 of the License, or\r
   8  *   (at your option) any later version.\r
   9  *\r
  10  *   This program is distributed in the hope that it will be useful,\r
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  13  *   GNU Library General Public License for more details.\r
  14  *\r
  15  *   You should have received a copy of the GNU Library General Public\r
  16  *   License along with this program; if not, write to the Free Software\r
  17  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.\r
  18  *----------------------------------------------------------------------\r
  19  */\r
  20 \r
  21 \r
  22 import java.io.IOException;\r
  23 import java.io.InputStream;\r
  24 import java.io.InvalidClassException;\r
  25 import java.io.InvalidObjectException;\r
  26 import java.io.ObjectInputStream;\r
  27 import java.io.ObjectOutputStream;\r
  28 import java.io.OutputStream;\r
  29 import java.lang.reflect.Array;\r
  30 \r
  31 /**\r
  32  * The JavaLayerUtils class is not strictly part of the JavaLayer API.\r
  33  * It serves to provide useful methods and system-wide hooks.\r
  34  * \r
  35  * @author MDM\r
  36  */\r
  37 public class JavaLayerUtils\r
  38 {\r
  39         static private JavaLayerHook    hook = null;\r
  40         \r
  41         /**\r
  42          * Deserializes the object contained in the given input stream.\r
  43          * @param in    The input stream to deserialize an object from.\r
  44          * @param cls   The expected class of the deserialized object. \r
  45          */\r
  46         static public Object deserialize(InputStream in, Class cls)\r
  47                 throws IOException\r
  48         {\r
  49                 if (cls==null)\r
  50                         throw new NullPointerException("cls");\r
  51                 \r
  52                 Object obj = deserialize(in, cls);\r
  53                 if (!cls.isInstance(obj))\r
  54                 {\r
  55                         throw new InvalidObjectException("type of deserialized instance not of required class.");\r
  56                 }\r
  57                 \r
  58                 return obj;\r
  59         }\r
  60         \r
  61         /**\r
  62          * Deserializes an object from the given <code>InputStream</code>.\r
  63          * The deserialization is delegated to an <code>\r
  64          * ObjectInputStream</code> instance. \r
  65          * \r
  66          * @param in    The <code>InputStream</code> to deserialize an object\r
  67          *                              from.\r
  68          * \r
  69          * @return The object deserialized from the stream. \r
  70          * @exception IOException is thrown if there was a problem reading\r
  71          *              the underlying stream, or an object could not be deserialized\r
  72          *              from the stream.\r
  73          * \r
  74          * @see java.io.ObjectInputStream\r
  75          */\r
  76         static public Object deserialize(InputStream in)\r
  77                 throws IOException\r
  78         {\r
  79                 if (in==null)\r
  80                         throw new NullPointerException("in");\r
  81                 \r
  82                 ObjectInputStream objIn = new ObjectInputStream(in);\r
  83                 \r
  84                 Object obj;\r
  85                 \r
  86                 try\r
  87                 {\r
  88                         obj = objIn.readObject();\r
  89                 }\r
  90                 catch (ClassNotFoundException ex)\r
  91                 {\r
  92                         throw new InvalidClassException(ex.toString());\r
  93                 }\r
  94                 \r
  95                 return obj;\r
  96         }\r
  97 \r
  98         /**\r
  99          * Deserializes an array from a given <code>InputStream</code>.\r
 100          * \r
 101          * @param in            The <code>InputStream</code> to \r
 102          *                                      deserialize an object from.\r
 103          *                              \r
 104          * @param elemType      The class denoting the type of the array\r
 105          *                                      elements.\r
 106          * @param length        The expected length of the array, or -1 if\r
 107          *                                      any length is expected.\r
 108          */\r
 109         static public Object deserializeArray(InputStream in, Class elemType, int length)\r
 110                 throws IOException\r
 111         {\r
 112                 if (elemType==null)\r
 113                         throw new NullPointerException("elemType");\r
 114                 \r
 115                 if (length<-1)\r
 116                         throw new IllegalArgumentException("length");\r
 117                 \r
 118                 Object obj = deserialize(in);\r
 119                 \r
 120                 Class cls = obj.getClass();\r
 121                 \r
 122                 \r
 123                 if (!cls.isArray())\r
 124                         throw new InvalidObjectException("object is not an array");\r
 125                 \r
 126                 Class arrayElemType = cls.getComponentType();\r
 127                 if (arrayElemType!=elemType)\r
 128                         throw new InvalidObjectException("unexpected array component type");\r
 129                                 \r
 130                 if (length != -1)\r
 131                 {\r
 132                         int arrayLength = Array.getLength(obj);\r
 133                         if (arrayLength!=length)\r
 134                                 throw new InvalidObjectException("array length mismatch");\r
 135                 }\r
 136                 \r
 137                 return obj;\r
 138         }\r
 139 \r
 140         static public Object deserializeArrayResource(String name, Class elemType, int length)\r
 141                 throws IOException\r
 142         {               \r
 143                 InputStream str = getResourceAsStream(name);\r
 144                 if (str==null)\r
 145                         throw new IOException("unable to load resource '"+name+"'");\r
 146                 \r
 147                 Object obj = deserializeArray(str, elemType, length);\r
 148                 \r
 149                 return obj;\r
 150         }       \r
 151         \r
 152         static public void serialize(OutputStream out, Object obj)\r
 153                 throws IOException\r
 154         {\r
 155                 if (out==null)\r
 156                         throw new NullPointerException("out");\r
 157                 \r
 158                 if (obj==null)\r
 159                         throw new NullPointerException("obj");\r
 160                 \r
 161                 ObjectOutputStream objOut = new ObjectOutputStream(out);\r
 162                 objOut.writeObject(obj);\r
 163                                 \r
 164         }\r
 165 \r
 166         /**\r
 167          * Sets the system-wide JavaLayer hook.\r
 168          */\r
 169         static synchronized public void setHook(JavaLayerHook hook0)            \r
 170         {\r
 171                 hook = hook0;\r
 172         }\r
 173         \r
 174         static synchronized public JavaLayerHook getHook()\r
 175         {\r
 176                 return hook;    \r
 177         }\r
 178         \r
 179         /**\r
 180          * Retrieves an InputStream for a named resource. \r
 181          * \r
 182          * @param name  The name of the resource. This must be a simple\r
 183          *                              name, and not a qualified package name.\r
 184          * \r
 185          * @return              The InputStream for the named resource, or null if\r
 186          *                              the resource has not been found. If a hook has been \r
 187          *                              provided, its getResourceAsStream() method is called\r
 188          *                              to retrieve the resource. \r
 189          */\r
 190         static synchronized public InputStream getResourceAsStream(String name)\r
 191         {\r
 192                 InputStream is = null;\r
 193                 \r
 194                 if (hook!=null)\r
 195                 {\r
 196                         is = hook.getResourceAsStream(name);    \r
 197                 }\r
 198                 else\r
 199                 {\r
 200                         Class cls = JavaLayerUtils.class;\r
 201                         is = cls.getResourceAsStream(name);\r
 202                 }\r
 203                 \r
 204                 return is;              \r
 205         }\r
 206 }\r