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：
3 O( `9 v1 J  Q5 n
public Object buildActions () {
    super.buildActions();
. v9 |: `* g7 g: H2 [! a   
    // Create the list of simulation actions. We put these in
$ @) W6 j# T, ?1 v8 E    // an action group, because we want these actions to be
    // executed in a specific order, but these steps should
( B) A8 h1 i6 k' R. t5 H    // take no (simulated) time. The M(foo) means "The message
5 v; r$ T) f5 }    // called <foo>". You can send a message To a particular
# |' s# O& l0 L2 x5 i3 N' S8 u% @    // object, or ForEach object in a collection.
        
, B3 |" S1 B/ J0 ^$ j    // Note we update the heatspace in two phases: first run
1 f2 }# \+ C% x. Z    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
! u* A9 J; V. [. E& M* l3 G! g    // significant!
        
    // Note also, that with the additional
    // `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
; ^7 f6 W9 C: [2 h; J- E    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
- J* `' q9 F6 q* J  V9 o: a    // 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
% {0 b; Z2 @& J4 H! m2 K5 B    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

0 z5 h9 q2 E( z    try {
* Y/ M) b6 |+ @! h/ \, B      modelActions.createActionTo$message
0 W: f. F: Z" k! M: Y  B7 C        (heat, new Selector (heat.getClass (), "stepRule", false));
1 X7 ~) m3 N- m% w4 O    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
9 {) B8 @% W" q, [+ _    }

$ j& }5 ]2 k, b! R    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
! h, |( j! t+ v' Z; n" n        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
8 n, q. {3 a0 `0 C4 r8 z/ q* J                        new FArgumentsImpl (this, sel)));
- {* H' l- \5 H9 B2 ?5 B    } catch (Exception e) {
+ z1 O/ S$ k" }! M2 w3 u  K      e.printStackTrace (System.err);
3 b0 q  V1 _/ p9 l4 O3 n  L    }
   
    syncUpdateOrder ();
. T8 \1 V4 d  I; _( t- H
- u0 |+ f1 `! E    try {
4 b! U0 R% Z, d; D      modelActions.createActionTo$message
- P1 C" }/ _4 S8 N/ G. a# }        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
3 R( U, W6 n& @+ m/ l0 }2 d      System.err.println("Exception updateLattice: " + e.getMessage ());
, M7 [* m( V8 M* }: ~2 X$ y    }
! g: i. b! n1 E5 ?        
    // Then we create a schedule that executes the
8 F9 w/ N, \" H* _0 {: e0 C    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
  [3 m" u- m" z5 }    // schedule has a repeat interval of 1, it will loop every
# R/ {$ v! v( m& j& K9 S    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
" @$ q* @3 j2 f% N* s8 N+ `
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
/ y- w: X2 J) s5 J  
6 x9 R( L6 a, }1 D' }* X1 Q! g# q) L% f    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
  }