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：
  D3 b; H3 B" ?1 B
public Object buildActions () {
4 r8 v6 O3 M% y( L    super.buildActions();
   
- p6 e, p' v( V* M. V    // Create the list of simulation actions. We put these in
- o9 O6 B: ?7 @4 m$ d2 p( U( B/ N- g    // an action group, because we want these actions to be
    // executed in a specific order, but these steps should
1 W) z' b: w" `7 R    // 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.
+ J" d, h+ e% K6 l) J        
' ?% M6 H6 `! `5 N. L    // 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
! c9 Q4 l% t3 U; q    // 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
$ W& y' l; r' w2 Y7 u# @9 d    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
  S$ Q  q3 r# B0 k4 \! U/ M9 |    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
8 K$ N( W7 r: ?8 ]    // identical (assuming the list order is not changed
    // indirectly by some other process).
3 u0 J# Q1 z* B   
: P: U; o8 d- t" a, _( _    modelActions = new ActionGroupImpl (getZone ());
: U0 Q7 w" b7 u- @! R. F
    try {
) b4 E5 R7 y6 z& n      modelActions.createActionTo$message
0 D5 \6 f; X$ N        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
9 U5 `$ ~, t$ I- v      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
) \% n; t  _0 H# k      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
! ^" P; P0 J0 j/ V0 ~$ k- B2 K        (heatbugList,
& E  Z1 }' s8 S- T+ q7 `9 S* g& ~         new FCallImpl (this, proto, sel,
0 I. T" d$ ~8 G8 G  K4 t1 n                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
; ^; ^+ Y2 |: v    }
   
. [2 d4 @' l+ K4 O' Z" {5 D6 ^+ V    syncUpdateOrder ();
% W* e2 i6 o6 F- V. F
. g7 _* N; m' i8 s    try {
& Q5 W4 w8 E: C      modelActions.createActionTo$message
* W" V" ]# k5 ]" X        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
7 I/ s0 x: Y4 ~        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
4 B6 [1 O9 `9 R/ ^* r4 i, \8 q    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
. z1 n. S3 s( ~0 l3 [" x    // modelActions ActionGroup at particular times.  This
/ Z% a! ]9 w7 d: G! K    // 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.

  ]: g- a  _# `# V- j/ B    // This is a simple schedule, with only one action that is
2 O, a, q8 a( I, F    // just repeated every time. See jmousetrap for more
    // complicated schedules.
1 G2 m+ J2 `" F6 f: i9 s: M# U  
, {- F( c7 U3 J  m" j! R    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
8 o) E$ j8 L6 Y: o) }' @    return this;
  }