问jheatbugs-2001-03-28中某些代码

sybbk

HeatbugModelSwarm中buildActions部分，3个try分别是做什么？查了下refbook-java-2.2，解释太简略，还是不懂，高手指点，谢谢！代码如下：

9 T9 n1 K7 D$ K! _4 t public Object buildActions () {
    super.buildActions();
* R# J8 O. O' A% l9 C   
7 W# S+ F8 Q4 U" K7 s' ~" L    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
    // executed in a specific order, but these steps should
+ H+ Y) \0 G* P; S' c+ y, s1 y/ M2 \    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
        
    // Note we update the heatspace in two phases: first run
) M/ p& ]% y1 f6 t    // diffusion, then run "updateWorld" to actually enact the
# s% o- O- L& B    // changes the heatbugs have made. The ordering here is
$ \4 b# }0 ]9 x/ j/ a7 @( |* L# [    // significant!
" J( K- q9 d0 N4 @        
# t0 T$ s- W% s" |3 @0 ~    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
% }, Z4 c, v; K% o: N) h    // their step rule.  This has the effect of removing any
; f# q& O% o& m0 O) `; }/ S  _    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
2 f( e0 Y2 h* ?- o    // By default, all `createActionForEach' modelActions have
- @# i0 ~4 s1 U% H+ C    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
8 b4 b; w6 T- K( `% |! U3 C    // identical (assuming the list order is not changed
2 ~( l" O1 b2 Y) A; P% d" w    // indirectly by some other process).
   
) f6 A2 T" C, }9 U9 w    modelActions = new ActionGroupImpl (getZone ());
4 q- M% }  g3 n7 _5 t
! P1 a8 T; Y% B  F6 k# L- ~0 Y    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
9 \: {) i" a% l1 s- X) d
& D! |8 a" |1 V8 F    try {
) L9 D% f# }8 d. R5 X      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
: K8 C( s5 T' `, r2 [5 N$ ?      actionForEach =
$ {2 F: o- `) x0 n# ^% u% n+ N2 V        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
& \* j) E9 J, P+ P5 Y8 f, k                        new FArgumentsImpl (this, sel)));
% B/ p3 |- T$ M    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
   
    syncUpdateOrder ();

    try {
) {+ ?" U! N1 p, E      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
+ @( F4 N: V* ]% n5 x- N    }
        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
3 j! y2 P) h, a8 c- |8 ~5 o    // modelActions ActionGroup at particular times.  This
# M) ?3 c/ A/ Q3 D. B    // schedule has a repeat interval of 1, it will loop every
    // time step.  The action is executed at time 0 relative to
, g- o/ L5 ^6 c' \* ]    // the beginning of the loop.
  c) R+ r  q" a  ?# n0 j
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
2 a; c7 q% E( F+ t% O    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
2 Q6 |# |8 J  {3 F" J1 u: y        
" k) |2 h" ]. T; x& `    return this;
  }