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：

public Object buildActions () {
    super.buildActions();
   
    // 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
5 M6 `; b% t" \* z! s  @+ f    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
1 i  T  ?- u; p1 f: o, x1 M    // object, or ForEach object in a collection.
        
) Q* i5 m$ k6 h- W* s, q+ A# V  F    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
) d& \7 b% g  B7 S. X, E8 c' R$ \    // changes the heatbugs have made. The ordering here is
' }; Y( k2 H+ L9 T6 {    // significant!
        
' m( K7 F& j2 |; F    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
  L$ J, _0 o3 @' p% X    // 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
    // list from timestep to timestep
! a$ g/ d4 ]# }$ d5 A" S3 _, o        
1 B4 V0 d5 A5 M0 O/ q. R    // By default, all `createActionForEach' modelActions have
- f2 r' c. j3 E$ r    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
; S4 z( V1 W/ F. ^  ~    // identical (assuming the list order is not changed
! _6 W1 O4 G6 |  R    // indirectly by some other process).
' f! s3 C8 v. |0 T, u9 K   
7 O: I& \+ ~& L' U$ f% D, S* U% s    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
- @" d# o8 a  |7 F        (heat, new Selector (heat.getClass (), "stepRule", false));
8 R. z8 |$ |. N: z    } catch (Exception e) {
+ i+ g: v  e0 W& c4 H+ F      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
, H; ]* H% _" V9 x- e: ?
    try {
# p2 E/ v7 X3 v" v+ K      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
4 V. W2 A4 c0 `. l0 @      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
7 v  m& ^6 Q5 J0 G        (heatbugList,
6 @# |2 f- B: m. x/ R' x         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
/ R4 n- _2 o3 x% ]   
    syncUpdateOrder ();
) T, H4 M+ t. }3 q2 x, ]! r
1 Q9 n& H4 K# [  P$ c8 `% @6 T    try {
      modelActions.createActionTo$message
; V' a$ e4 i: B; E+ s8 W        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
" p0 n% b8 E5 c# C    }
        
    // 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
% R6 ~4 `5 ]- K" y    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
" ?/ U1 N+ ^) G: `0 B    // 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.

& i3 ~5 e8 k  }% p) [    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
5 I) P4 r# A7 K+ E    // complicated schedules.
  
1 T9 j4 P! g1 [* r    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
2 H( [* N% N! T  D1 T        
5 c; J/ C( {  B; l7 b) B9 i5 }1 o    return this;
  }