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：

- o# `" _* y7 Y$ t public Object buildActions () {
    super.buildActions();
   
) O- @( l+ S# x8 e4 P. T    // 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
    // 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.
# N: n% ^6 G4 R. B/ h        
    // Note we update the heatspace in two phases: first run
  k/ X8 D- v" W- h( p# r' r    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
" `' |8 C' ~) ?1 f    // significant!
+ A. w% o+ |# d! W8 `  d4 F' j3 I: C        
* a  J) V/ r3 m9 N& I: a    // Note also, that with the additional
! K5 C# G. N! _# Z    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
% A/ n- ]' F) }2 G& }    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
+ ~/ s$ ?* V0 r  ?+ M    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
3 m! g9 ^  W/ Z7 k$ S    modelActions = new ActionGroupImpl (getZone ());

( h  d4 g) p6 u. v( O    try {
" r. w) ?: U$ X. C8 p! M$ r      modelActions.createActionTo$message
! B1 N7 y9 ]1 `; v2 }- F        (heat, new Selector (heat.getClass (), "stepRule", false));
: T& _5 e) P; P    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
0 d( V/ C6 N- U2 Z- _6 s    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
3 X0 k2 N7 S: {+ |* I: W      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
* j; W# }% D4 l3 B      actionForEach =
' r8 V& y/ D3 \6 b) w$ o5 E, b        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
' b5 r9 o: @9 K0 e; n' W         new FCallImpl (this, proto, sel,
. n8 [$ r  E, L. w) P& R                        new FArgumentsImpl (this, sel)));
1 P# U9 ]) u5 |6 I, ~    } catch (Exception e) {
+ ~* T) o; s8 u      e.printStackTrace (System.err);
& f/ O9 ^2 ]5 g* g    }
4 x$ M; U/ T7 \, B8 b7 }% j4 q   
    syncUpdateOrder ();
8 [7 T2 W( R* j# r) V
* r2 ]- a# m5 C8 ?    try {
      modelActions.createActionTo$message
, S- x( n! U$ k- c' a9 ]# ^        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
! x+ g3 D! J4 c      System.err.println("Exception updateLattice: " + e.getMessage ());
8 p3 }3 P* [6 N. S1 o    }
/ |- m. @4 P) |+ E9 ~        
    // Then we create a schedule that executes the
- `: X) B5 S# y1 B9 f6 |4 v" e) y    // modelActions. modelActions is an ActionGroup, by itself it
+ }5 F4 A; _# k    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
7 Z& D1 |7 ~2 C. k9 e) V    // modelActions ActionGroup at particular times.  This
- y' w% O! L  w  _7 w% F    // schedule has a repeat interval of 1, it will loop every
3 }' q+ n* s5 a( B/ d- n) B2 P    // time step.  The action is executed at time 0 relative to
  t6 @8 X9 n9 u: j2 o1 W: G    // the beginning of the loop.
  s/ a# N2 u3 }8 i
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
. o' n# _3 ?9 R    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
8 K+ J) b' o) p% h2 U( L    return this;
  }