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：
) r3 c" @! P* y. F2 H
public Object buildActions () {
# O) u8 ~2 F: }; r    super.buildActions();
   
% `9 M5 A; x5 E: x    // Create the list of simulation actions. We put these in
( ?$ l5 D8 U& S8 A  T1 a) _# j4 [    // an action group, because we want these actions to be
    // executed in a specific order, but these steps should
5 X% `. j$ o! `( }  _: q1 R    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
/ I  k# z( b) o7 f    // object, or ForEach object in a collection.
        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
' N, ?2 A1 U+ o2 m$ W7 R  Y    // changes the heatbugs have made. The ordering here is
$ t% j2 [9 O5 }- Z    // significant!
6 M  D. l, W) k! o  w        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
, M+ Y4 W) f, T- `7 H& \* I8 ^    // 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
2 \) f1 R1 \: l1 R; k. b    // list from timestep to timestep
        
$ u2 A$ o, t) _! `2 ?. L    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
, B* l* u5 y& F/ Z4 Q/ b    // identical (assuming the list order is not changed
$ I0 ?3 q# n' T5 J) A1 U* W    // indirectly by some other process).
   
  M* H2 N* @# Z0 A$ K' h% q+ l" e) h    modelActions = new ActionGroupImpl (getZone ());

" ^' M8 ?* p4 S3 N( ]! p    try {
1 \# [) W% G4 s      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
) a5 c$ s0 s% ~% X
    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
( }4 K" ^; B2 b2 A4 ~; a# X" H      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
) }5 X3 x& c$ S6 a0 d  D        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
# G% P0 \* ~) R' W' S) G    } catch (Exception e) {
+ e9 [$ V6 w2 p6 W2 _      e.printStackTrace (System.err);
5 U% K! o& Y2 a+ j    }
   
    syncUpdateOrder ();

* [) `. i, Y# R% l    try {
  g4 \) j$ `! p4 H9 X      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
0 @1 Q6 ^  _/ r( ^! G8 ]0 y+ R    } catch (Exception e) {
# a& C4 l/ c1 Q      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
* h9 V+ n% @! P; V  f' l1 i  i. b: 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
; o; w9 u2 I) m2 ]6 i, G: s    // time, we create a Schedule that says to use the
$ R+ l. E# f( O& q# I) M    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
  r9 p4 u* q1 `    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
+ H8 v5 ^/ l& q
    // This is a simple schedule, with only one action that is
& i: S& b7 W. Q1 ?    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
& Q/ l, w$ |6 ]5 {0 H    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
! Z* a; Y5 n( C( t" q' z. d/ {        
4 I8 q" X: Q1 @- F6 k    return this;
/ T! K2 R1 h8 M. X6 z  }