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

   1 /* JdwpId.java -- base class for all object ID types
   2    Copyright (C) 2005 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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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
  45 /**
  46  * A baseclass for all object types reported to the debugger
  47  *
  48  * @author Keith Seitz  <keiths@redhat.com>
  49  */
  50 public abstract class JdwpId
  51 {
  52   /**
  53    * ID assigned to this object
  54    */
  55   protected long _id;
  56
  57   /**
  58    * Tag of ID's type (see {@link gnu.classpath.jdwp.JdwpConstants.Tag})
  59    * for object-like IDs or the type tag (see {@link
  60    * gnu.classpath.JdwpConstants.TypeTag}) for reference type IDs.
  61    */
  62   private byte _tag;
  63
  64   /**
  65    * Constructs an empty <code>JdwpId</code>
  66    */
  67   public JdwpId (byte tag)
  68   {
  69     _tag = tag;
  70   }
  71
  72   /**
  73    * Sets the id for this object reference
  74    */
  75   void setId (long id)
  76   {
  77     _id = id;
  78   }
  79
  80   /**
  81    * Returns the id for this object reference
  82    */
  83   public long getId ()
  84   {
  85     return _id;
  86   }
  87
  88   /**
  89    * Compares two object ids for equality. Two object ids
  90    * are equal if they point to the same type and contain to
  91    * the same id number. (NOTE: This is a much stricter check
  92    * than is necessary: all <code>JdwpId</code>s have unique
  93    * ids.)
  94    */
  95   public boolean equals (JdwpId id)
  96   {
  97     return ((id.getClass () == getClass ()) && (id.getId () == getId ()));
  98   }
  99
 100   /**
 101    * Returns size of this type (used by IDSizes)
 102    */
 103   public abstract int size ();
 104
 105   /**
 106    * Writes the contents of this type to the <code>DataOutputStream</code>
 107    * @param  outStream    the <code>DataOutputStream</code> to use
 108    * @throws IOException  when an error occurs on the <code>OutputStream</code>
 109    */
 110   public abstract void write (DataOutputStream outStream)
 111     throws IOException;
 112
 113   /**
 114    * Writes the contents of this type to the output stream, preceded
 115    * by a one-byte tag for tagged object IDs or type tag for
 116    * reference type IDs.
 117    *
 118    * @param  outStream    the <code>DataOutputStream</code> to use
 119    * @throws IOException  when an error occurs on the <code>OutputStream</code>
 120    */
 121   public void writeTagged (DataOutputStream outStream)
 122     throws IOException
 123   {
 124     outStream.writeByte (_tag);
 125     write (outStream);
 126   }
 127 }