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：

% _+ J8 }- C; _% M3 [" E' U public Object buildActions () {
, G& S: H( P* s3 Z" B3 L( ?4 W    super.buildActions();
   
% Y# z' [; D) ~    // Create the list of simulation actions. We put these in
% K& S2 x; x  |" P5 Z7 d& k$ c+ R3 X6 W    // 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
$ `6 v2 j$ R4 ~6 q    // object, or ForEach object in a collection.
$ L) ^; H, |& K) ?3 g- m# T- b        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
    // significant!
' C9 \$ \# ?# ]6 h4 j        
" D2 R% L3 {: i) {$ E8 F0 l    // Note also, that with the additional
& P; ]3 j+ b# w# N    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
( b' g# ^( n; e1 m% Q    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
% j5 {- i; p: w& g    // By default, all `createActionForEach' modelActions have
: w0 K7 G3 |" K: w* ^$ B" R    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
" }. _# W& C  k5 q5 m    // indirectly by some other process).
  h; d1 H; }. p4 h   
    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
; a; d  ^7 u1 _, a. D        (heat, new Selector (heat.getClass (), "stepRule", false));
* U$ L( N( G# G  N    } catch (Exception e) {
4 T+ Z3 Y2 g. D4 J      System.err.println ("Exception stepRule: " + e.getMessage ());
9 e) v8 @3 {1 {# T; U    }
8 f+ \- w6 w, C: W
2 k, i5 v1 t2 N    try {
3 b, @3 d4 U; m" T# E0 m      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
& R8 H. I% N: r% D        (heatbugList,
* ?; k$ w8 P, o- `         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
! @1 K3 x  Y7 u7 b% w- M    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
0 u+ ?9 m3 l) C% V7 \" C/ I) F9 z   
    syncUpdateOrder ();
( j4 {9 [# f) o  L# O1 x1 s
# E5 o* v6 I- i, S; E8 r    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
  N( E( j" q' P+ a# @      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
: }5 N  B& n+ E7 j0 `$ w) u    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
7 y, B! k- U$ g" j3 P    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
: p6 _$ }% N8 G  c+ @    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
* V& ?, V/ o, m5 Q4 U" n    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
; H; Q/ @! R8 H2 g7 h% L, G
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
' u! E4 J& z; G) B    // complicated schedules.
  
5 C- @4 Z  }7 A* b    modelSchedule = new ScheduleImpl (getZone (), 1);
0 E% @1 a. [9 \7 q* o2 R- j4 ]: p    modelSchedule.at$createAction (0, modelActions);
        
    return this;
$ B' R! ~; u2 l1 z' J# _2 e7 K  }