Source for gnu.classpath.jdwp.id.JdwpId

   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., 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:    * ID assigned to this object
  55:    */
  56:   protected long _id;
  57: 
  58:   /**
  59:    * Tag of ID's type (see {@link gnu.classpath.jdwp.JdwpConstants.Tag})
  60:    * for object-like IDs or the type tag (see {@link
  61:    * gnu.classpath.JdwpConstants.TypeTag}) for reference type IDs.
  62:    */
  63:   private byte _tag;
  64: 
  65:   /**
  66:    * The object/class represented by this Id
  67:    */
  68:   protected SoftReference _reference;
  69: 
  70:   /**
  71:    * Constructs an empty <code>JdwpId</code>
  72:    */
  73:   public JdwpId (byte tag)
  74:   {
  75:     _tag = tag;
  76:   }
  77: 
  78:   /**
  79:    * Sets the id for this object reference
  80:    */
  81:   public void setId (long id)
  82:   {
  83:     _id = id;
  84:   }
  85: 
  86:   /**
  87:    * Returns the id for this object reference
  88:    */
  89:   public long getId ()
  90:   {
  91:     return _id;
  92:   }
  93: 
  94:   /**
  95:    * Gets the object/class reference for this ID
  96:    *
  97:    * @returns a refernce to the object or class
  98:    */
  99:   public SoftReference getReference ()
 100:   {
 101:     return _reference;
 102:   }
 103: 
 104:   /**
 105:    * Sets the object/class reference for this ID
 106:    *
 107:    * @param ref a refernce to the object or class
 108:    */
 109:   public void setReference (SoftReference ref)
 110:   {
 111:     _reference = ref;
 112:   }
 113: 
 114:   /**
 115:    * Compares two object ids for equality. Two object ids
 116:    * are equal if they point to the same type and contain to
 117:    * the same id number. 
 118:    */
 119:   public boolean equals (JdwpId id)
 120:   {
 121:     return (id.getId () == getId ());
 122:   }
 123: 
 124:   /**
 125:    * Returns size of this type (used by IDSizes)
 126:    */
 127:   public abstract int size ();
 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: }