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：

* b' R6 r+ |! d" b8 C public Object buildActions () {
# l7 R  T' z4 c; X; s$ s    super.buildActions();
   
    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
3 s7 z0 n7 W2 e    // 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.
/ `% X( n8 y; N, D        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
7 R1 W# L  x- q' t( ~5 e6 p) u    // changes the heatbugs have made. The ordering here is
    // significant!
6 k: ~1 P* f( F  _1 ^' w7 L0 |* \        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
; r+ c  R$ g" N& `+ F' R' c6 G    // randomize the order in which the bugs actually run
" P' |8 ^+ |2 j( i0 w7 u/ |    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
9 P- W: H$ Y/ @+ U. t8 a    // a default order of `Sequential', which means that the
6 I. B' R+ c' W    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
1 K9 o# \4 P/ h# q    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());
0 w9 S6 W+ Z/ |) W8 Y7 l' `4 S. L7 x
    try {
      modelActions.createActionTo$message
  _6 X0 R$ ?: |. f1 G' k# d2 p% S        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

! X4 S+ C4 Q  p6 x3 V" g    try {
; n! Z, W( y) G0 ?' Y2 k  i      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
+ v, X+ E1 R6 m* {        new Selector (proto.getClass (), "heatbugStep", false);
7 T# l) [+ \/ q      actionForEach =
) {3 R7 K1 U5 J% v- P* ]        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
0 Z9 r! x" e/ [3 Y                        new FArgumentsImpl (this, sel)));
' z+ Z4 K# ~- I    } catch (Exception e) {
      e.printStackTrace (System.err);
( Q: U5 H* A8 N: W    }
+ B# M! \: E. ?: b7 a# I   
    syncUpdateOrder ();

/ R; z/ B6 O- O# V5 ?1 K. R    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
' m& i+ z+ P0 X' M1 I      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
    // Then we create a schedule that executes the
9 ~& V8 e0 v  e- W3 t    // modelActions. modelActions is an ActionGroup, by itself it
  S9 \. N& d9 K8 w5 @! p7 x$ L    // has no notion of time. In order to have it executed in
7 N1 M* o# X9 w. p* q    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
    // time step.  The action is executed at time 0 relative to
  b- ]" Y# \7 Q. j+ f/ Q/ X, V  b    // the beginning of the loop.
  _* W) D) I* v) \2 [$ T  L
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
) M+ J' K( O8 g7 b+ E  ]0 H    // complicated schedules.
  
7 h. N( |: g$ n    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
, w- V" v8 Q/ }+ Z- |        
! F) J0 G2 N# j$ d' W9 F    return this;
# F) k# G9 P; I; k  }