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：

& X. w0 g; g/ Y( m public Object buildActions () {
4 B4 A0 n, _1 K( G+ X3 Z9 D% M    super.buildActions();
   
    // Create the list of simulation actions. We put these in
5 k9 T0 I* G4 |    // 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
! \7 S6 D. Z3 G8 l7 o2 t! y    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
        
    // Note we update the heatspace in two phases: first run
  s7 P2 C8 I) Y0 O    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
# d5 W; ?2 t4 B2 X    // significant!
        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
5 a/ n7 h9 `# T5 q% K) B: j$ r0 C- Y    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
) b8 S5 s* v1 k$ @# u  N# ~        
- m( _: u0 R" L2 [; S* f8 u    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
, x0 [$ ]) J9 s  |    // identical (assuming the list order is not changed
7 t9 b8 ~9 r4 [  b1 R    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

8 W1 i# b, m9 u    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
  x; B! X+ d9 j+ b; G& `: t/ ~, B+ e    }
4 C- v" m' p. Q( a5 e7 d2 w
    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
* G/ D; Y" Q+ A# b+ L      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
5 x9 Y9 b+ q: i9 G  o6 V. A        (heatbugList,
" f, }- ?# s% r: L6 c3 U4 K6 a         new FCallImpl (this, proto, sel,
+ J1 g2 B+ p7 {) U0 _0 r                        new FArgumentsImpl (this, sel)));
6 D9 J- t" E, q9 _! O7 t& g, b* I6 Z1 K4 l    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
+ Z8 t! ^" F) K" H# V' D, s   
7 o& }6 Q: d5 n1 e    syncUpdateOrder ();

$ E: B  z( d& f: u' _  L    try {
! H- H6 ~: p6 E/ L- s      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
# {0 |2 y4 q6 Z6 A3 u    } catch (Exception e) {
/ Y* i: Q  e1 L0 L      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
) u$ Q$ A/ Z* M: a  }# k        
- g7 G) h  ]# @8 n6 e( p$ V    // Then we create a schedule that executes the
+ v3 i# h4 N, b9 W  P( s$ `' o    // 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
    // schedule has a repeat interval of 1, it will loop every
* l) _+ b% k* b; Z+ I    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.

# t" T. X' m6 s0 M  y6 l    // This is a simple schedule, with only one action that is
( d' V) b3 O' ^0 R    // just repeated every time. See jmousetrap for more
  _* d% l1 ^9 ?2 x, I    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
4 N: y( @' d2 @% [6 c( W    return this;
  }