Source for gnu.classpath.jdwp.id.JdwpId

   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: }