Source for gnu.classpath.jdwp.event.filters.StepFilter

   1: /* StepFilter.java -- a step filter
   2:    Copyright (C) 2005, 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: 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.event.filters;
  41: 
  42: import gnu.classpath.jdwp.event.Event;
  43: import gnu.classpath.jdwp.exception.InvalidThreadException;
  44: import gnu.classpath.jdwp.id.ThreadId;
  45: 
  46: /**
  47:  * "An event filter which restricts reported step events to those which
  48:  * satisfy depth and size constraints. This modifier can only be used with
  49:  * step event kinds."
  50:  *
  51:  * This "filter" is not really a filter. It is simply a way to communicate
  52:  * stepping information in a convenient way between the JDWP backend and
  53:  * the virtual machine.
  54:  *
  55:  * Consequently, this "filter" always matches.
  56:  *
  57:  * @author Keith Seitz  (keiths@redhat.com)
  58:  */
  59: public class StepFilter
  60:   implements IEventFilter
  61: {
  62:   private ThreadId _tid;
  63:   private int _size;
  64:   private int _depth;
  65: 
  66:   /**
  67:    * Constructs a new StepFilter
  68:    *
  69:    * @param tid    ID of the thread in which to step
  70:    * @param size   size of each step
  71:    * @param depth  relative call stack limit
  72:    * @throws InvalidThreadException if thread is invalid
  73:    */
  74:   public StepFilter (ThreadId tid, int size, int depth)
  75:     throws InvalidThreadException
  76:   {
  77:     if (tid.getReference().get () == null)
  78:       throw new InvalidThreadException (tid.getId ());
  79: 
  80:     _tid = tid;
  81:     _size = size;
  82:     _depth = depth;
  83:   }
  84: 
  85:   /**
  86:    * Returns the thread in which to step
  87:    *
  88:    * @return the thread's ID
  89:    */
  90:   public ThreadId getThread ()
  91:   {
  92:     return _tid;
  93:   }
  94: 
  95:   /**
  96:    * Returns the size of each step (insn, line)
  97:    *
  98:    * @return the step size
  99:    * @see gnu.classpath.jdwp.JdwpConstants.StepSize
 100:    */
 101:   public int getSize ()
 102:   {
 103:     return _size;
 104:   }
 105: 
 106:   /**
 107:    * Returns the relative call stack limit (into, over, out)
 108:    *
 109:    * @return how to step
 110:    * @see gnu.classpath.jdwp.JdwpConstants.StepDepth
 111:    */
 112:   public int getDepth ()
 113:   {
 114:     return _depth;
 115:   }
 116: 
 117:   /**
 118:    * Does the given event match the filter?
 119:    *
 120:    * @param event  the <code>Event</code> to scrutinize
 121:    */
 122:   public boolean matches (Event event)
 123:   {
 124:     return true;
 125:   }
 126: }