libjava/classpath/gnu/classpath/jdwp/id/JdwpId.java

   1 /* JdwpId.java -- base class for all object ID types
   2    Copyright (C) 2005, 2006 Free Software Foundation
   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 terms of your choice, provided that you also meet, for each linked
  32 independent module, the terms and conditions of the license of that
  33 module.  An independent module is a module which is not derived from
  34 or based on this library.  If you modify this library, you may extend
  35 this exception to your version of the library, but you are not
  36 obligated to do so.  If you do not wish to do so, delete this
  37 exception statement from your version. */
  38
  39
  40 package gnu.classpath.jdwp.id;
  41
  42 import java.io.DataOutputStream;
  43 import java.io.IOException;
  44 import java.lang.ref.SoftReference;
  45
  46 /**
  47  * A baseclass for all object types reported to the debugger
  48  *
  49  * @author Keith Seitz  <keiths@redhat.com>
  50  */
  51 public abstract class JdwpId
  52 {
  53   /**
  54    * The size of an ID. The default is 8 bytes (a long).
  55    */
  56    public static final int SIZE = 8;
  57
  58   /**
  59    * ID assigned to this object
  60    */
  61   protected long _id;
  62
  63   /**
  64    * Tag of ID's type (see {@link gnu.classpath.jdwp.JdwpConstants.Tag})
  65    * for object-like IDs or the type tag (see {@link
  66    * gnu.classpath.jdwp.JdwpConstants.TypeTag}) for reference type IDs.
  67    */
  68   private byte _tag;
  69
  70   /**
  71    * The object/class represented by this Id
  72    */
  73   protected SoftReference _reference;
  74
  75   /**
  76    * Constructs an empty <code>JdwpId</code>
  77    */
  78   public JdwpId (byte tag)
  79   {
  80     _tag = tag;
  81   }
  82
  83   /**
  84    * Sets the id for this object reference
  85    */
  86   public void setId (long id)
  87   {
  88     _id = id;
  89   }
  90
  91   /**
  92    * Returns the id for this object reference
  93    */
  94   public long getId ()
  95   {
  96     return _id;
  97   }
  98
  99   /**
 100    * Gets the object/class reference for this ID
 101    *
 102    * @returns a refernce to the object or class
 103    */
 104   public SoftReference getReference ()
 105   {
 106     return _reference;
 107   }
 108
 109   /**
 110    * Sets the object/class reference for this ID
 111    *
 112    * @param ref a refernce to the object or class
 113    */
 114   public void setReference (SoftReference ref)
 115   {
 116     _reference = ref;
 117   }
 118
 119   /**
 120    * Compares two object ids for equality. Two object ids
 121    * are equal if they point to the same type and contain to
 122    * the same id number.
 123    */
 124   public boolean equals (JdwpId id)
 125   {
 126     return (id.getId () == getId ());
 127   }
 128
 129   /**
 130    * Writes the contents of this type to the <code>DataOutputStream</code>
 131    * @param  outStream    the <code>DataOutputStream</code> to use
 132    * @throws IOException  when an error occurs on the <code>OutputStream</code>
 133    */
 134   public abstract void write (DataOutputStream outStream)
 135     throws IOException;
 136
 137   /**
 138    * Writes the contents of this type to the output stream, preceded
 139    * by a one-byte tag for tagged object IDs or type tag for
 140    * reference type IDs.
 141    *
 142    * @param  outStream    the <code>DataOutputStream</code> to use
 143    * @throws IOException  when an error occurs on the <code>OutputStream</code>
 144    */
 145   public void writeTagged (DataOutputStream outStream)
 146     throws IOException
 147   {
 148     outStream.writeByte (_tag);
 149     write (outStream);
 150   }
 151 }