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();
* y% }7 V7 r6 q   
    // Create the list of simulation actions. We put these in
9 E# r! @; b8 m    // an action group, because we want these actions to be
4 C8 ?, V7 v* f" I    // executed in a specific order, but these steps should
    // 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.
        
/ h; N! @4 I) t( b  M4 m    // 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
    // significant!
        
8 v: u6 J6 V# o    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
* l. d# V) M. L    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
- S/ P- M% N0 U2 H+ P' d    // systematic bias in the iteration throught the heatbug
1 Y8 {/ }, ]6 v6 m& ]6 c7 }, t    // list from timestep to timestep
) ?3 x/ i6 b  y4 r  Q5 s; |        
    // By default, all `createActionForEach' modelActions have
) [3 w5 g6 B; Z3 Y0 O    // a default order of `Sequential', which means that the
0 q1 g6 r( A$ t    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
# f% B7 n6 k5 M    // indirectly by some other process).
( w* u/ t$ `' L* N' d# v0 \   
; q# i& u( c' Y- y9 f5 I    modelActions = new ActionGroupImpl (getZone ());
% e# }4 n/ a" G2 i" U# F
    try {
6 u3 a+ T$ z3 R& X      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
/ n) I6 \! P9 N    }
4 ]; t( y5 K8 f( s% ]6 p0 G! t) Z
: _( O+ ^* W$ e/ w' m    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
6 F5 u1 v% k9 K5 E" E        (heatbugList,
7 s' U" e# R& `; K; a         new FCallImpl (this, proto, sel,
+ {6 _; O& d; \; u# a                        new FArgumentsImpl (this, sel)));
0 ~- X, k" ?  X: x( N    } catch (Exception e) {
% b8 I* A6 U  f8 n% _      e.printStackTrace (System.err);
    }
  `. [  b% y# `& a) V# M   
8 ~0 t; M  A: y# H" g' }8 O: i    syncUpdateOrder ();
4 G- B* h% P  [4 H- J2 {
    try {
      modelActions.createActionTo$message
# A( J0 s: q# U$ m" a% x# `        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
! ^0 q/ G, g% a      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
    // Then we create a schedule that executes the
; V/ a$ M2 ?( ^3 d& {, r' b9 y    // modelActions. modelActions is an ActionGroup, by itself it
) `- x5 {+ Q, ^5 s% k9 C    // 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
( w# t' b" b: Q" c+ g1 `- T    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.

$ N6 @7 c: t3 j, m! K    // This is a simple schedule, with only one action that is
" h% k8 [8 `0 d/ l+ N. T  N    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
/ B6 K# V# T5 H+ U7 `        
+ L. y1 H  b0 S0 r8 k) C    return this;
7 W5 W7 N1 d, A' k* W$ ~$ Z3 r  }