Source for gnu.classpath.jdwp.util.Location

   1: /* Location.java -- class to read/write JDWP locations
   2:    Copyright (C) 2005, 2006, 2007 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: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package gnu.classpath.jdwp.util;
  40: 
  41: import gnu.classpath.jdwp.VMIdManager;
  42: import gnu.classpath.jdwp.VMMethod;
  43: import gnu.classpath.jdwp.exception.JdwpException;
  44: import gnu.classpath.jdwp.id.ClassReferenceTypeId;
  45: 
  46: import java.io.DataOutputStream;
  47: import java.io.IOException;
  48: import java.nio.ByteBuffer;
  49: 
  50: /**
  51:  * A class to read/write JDWP locations.
  52:  *
  53:  * @author Aaron Luchko <aluchko@redhat.com>
  54:  */
  55: public class Location
  56: {
  57:   private VMMethod method;
  58:   private long index;
  59: 
  60:   /**
  61:    * Create a location with the given parameters.
  62:    *
  63:    * @param method the method
  64:    * @param index location in the method
  65:    */
  66:   public Location(VMMethod method, long index)
  67:   {
  68:     this.method = method;
  69:     this.index = index;
  70:   }
  71: 
  72:   /**
  73:    * Read a location from the given bytebuffer, consists of a TAG (byte),
  74:    * followed by a ReferenceTypeId, a MethodId and an index (long).
  75:    *
  76:    * @param bb this holds the location
  77:    * @throws IOException    when an error occurs reading from the buffer
  78:    * @throws JdwpException  for invalid class or method IDs
  79:    */
  80:   public Location(ByteBuffer bb)
  81:     throws IOException, JdwpException
  82:   {
  83:     byte tag = bb.get();
  84:     ClassReferenceTypeId classId =
  85:       (ClassReferenceTypeId) VMIdManager.getDefault().readReferenceTypeId(bb);
  86:     Class klass = classId.getType();
  87:     method = VMMethod.readId(klass, bb);
  88:     index = bb.getLong();
  89:   }
  90: 
  91:   /**
  92:    * Write the given location to an output stream.
  93:    *
  94:    * @param os stream to write to
  95:    * @throws IOException when an error occurs writing to the stream
  96:    */
  97:   public void write(DataOutputStream os)
  98:     throws IOException
  99:   {
 100:     // check if this is an empty location
 101:     if (method != null)
 102:       {
 103:         VMIdManager idm = VMIdManager.getDefault();
 104:         ClassReferenceTypeId crti =
 105:           (ClassReferenceTypeId)
 106:           idm.getReferenceTypeId(method.getDeclaringClass());
 107: 
 108:         crti.writeTagged(os);
 109:         method.writeId(os);
 110:         os.writeLong(index);
 111:       }
 112:     else
 113:       {
 114:         os.writeByte(1);
 115:         os.writeLong((long) 0);
 116:         os.writeLong((long) 0);
 117:         os.writeLong((long) 0);
 118:       }
 119:   }
 120: 
 121:   /**
 122:    * Sets up an empty location
 123:    *
 124:    * @return new Location (setup as empty)
 125:    */
 126:   public static Location getEmptyLocation()
 127:   {
 128:        return new Location(null, 0);
 129:   }
 130: 
 131:   /**
 132:    * Gets the method of this location
 133:    *
 134:    * @return the method
 135:    */
 136:   public VMMethod getMethod()
 137:   {
 138:     return method;
 139:   }
 140: 
 141:   /**
 142:    * Gets the code index of this location
 143:    *
 144:    * @return the code index
 145:    */
 146:   public long getIndex ()
 147:   {
 148:     return index;
 149:   }
 150: 
 151:   // convenient for debugging
 152:   public String toString ()
 153:   {
 154:     return method.toString () + "." + index;
 155:   }
 156: 
 157:   public boolean equals(Object obj)
 158:   {
 159:     if (obj instanceof Location)
 160:       {
 161:         Location l = (Location) obj;
 162:         return (getMethod().equals(l.getMethod())
 163:                 && getIndex() == l.getIndex());
 164:       }
 165: 
 166:     return false;
 167:   }
 168: }