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：

$ T) i7 @, l3 J0 o2 e! B7 Q public Object buildActions () {
8 _' ~. a' G% r* h- P6 B    super.buildActions();
   
3 ~- j  L$ n- L. A, J    // 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
0 u- E* a: I/ d1 C4 m! u    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
7 K4 m& Z1 C$ I* X: D    // 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
    // changes the heatbugs have made. The ordering here is
9 C& y/ @$ T  s" V    // significant!
. S( ?5 N- o' S' ^        
! a9 A" W0 w, C% O6 s8 a0 H. ~1 B    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
1 ^+ C/ Q4 W) ~/ P# {    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
8 J; G) X1 ]1 _+ s' K' Y8 k5 ^! {& x5 b    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
: O% X* M  ^5 r. j    // order of iteration through the `heatbugList' will be
5 e* k- N6 Y0 V    // identical (assuming the list order is not changed
    // indirectly by some other process).
  ]/ o( T0 C# A- i9 m   
    modelActions = new ActionGroupImpl (getZone ());
# ]9 y+ ?1 }) x# A& T' t
    try {
/ o! h. q7 F5 w) ^      modelActions.createActionTo$message
4 P8 _9 H' A+ d- h        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
$ t+ n7 c! T: A& z+ X8 o    }

    try {
4 x$ j8 B2 R% O7 B      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
, S, `, f! i: H        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
! E1 V# g- G8 e  e$ D! S5 t# l' P0 P                        new FArgumentsImpl (this, sel)));
9 R3 ?2 Z% |5 \: H3 K( C    } catch (Exception e) {
1 \" p" J# r  p3 U      e.printStackTrace (System.err);
    }
   
4 n  R" @+ ]& K4 I. F    syncUpdateOrder ();
- @! C4 w9 n2 c& }  V
/ w* \+ ?% b+ e8 Y2 F9 W9 q0 w    try {
3 ]) X! ^' j, _8 m4 }3 n3 }# p      modelActions.createActionTo$message
5 S1 N" x( g) i        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
6 P' S! E1 A5 ^      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
% U" k* i% K+ |' _- U9 x" _: l    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
8 m" w* R6 ]6 l7 ^2 h    // has no notion of time. In order to have it executed in
/ S) p& b8 H" J3 i% |/ [    // time, we create a Schedule that says to use the
2 i$ j% X( O. O) }% X    // 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
    // the beginning of the loop.
/ a, ~" x& ~5 J, v
2 e  `# ?* z; |) R& t    // This is a simple schedule, with only one action that is
' L& p1 i' Q$ n& I4 w# p    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
3 k2 e0 {3 P0 M    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
  }