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 () {
) s& b2 z9 I8 Q/ D4 ?7 M    super.buildActions();
) O$ o0 v$ K6 u5 V   
* m% J1 q2 v' L. ^+ l9 y7 }    // Create the list of simulation actions. We put these in
- \$ [- D. b0 P. G& T' m    // an action group, because we want these actions to be
  S" Q) p6 g7 c0 X5 F! \    // 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.
% t8 p! w, N; F9 d9 X9 U6 [: M- B        
( S; @. i1 y3 Z% @! F" Z! g! s    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
$ }9 G+ O- i- T% r    // changes the heatbugs have made. The ordering here is
    // significant!
# H* U! j7 |9 [        
# z! x+ z0 C6 @8 u& l) c    // Note also, that with the additional
( ?( S9 i2 Q( ^    // `randomizeHeatbugUpdateOrder' Boolean flag we can
% m" u% l/ m" N3 {: i4 B8 m    // randomize the order in which the bugs actually run
! \, n+ X# u% t0 _4 i    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
    // 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
4 u( e7 t* q9 i    // indirectly by some other process).
2 w2 r- O3 ~- Z) u. F3 }   
8 B/ t+ W. E4 ^; f0 \    modelActions = new ActionGroupImpl (getZone ());
8 {. g" k2 x" v& R( I' ^' W/ Y
: f5 G2 d( y$ j! C% v    try {
      modelActions.createActionTo$message
) F( h) }; `' A: s$ K! L        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
9 L7 I$ c8 k, u* q$ T1 a8 Z) b# [9 g, ?9 p    }
/ T* \7 p0 r5 U! ?- f) E& M
    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
2 F% ]1 w* ?0 i6 ]; R1 _      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
( b: B9 L) ?* O4 O. f+ D1 P        (heatbugList,
  l) _. p5 o' t% j         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
8 S: h2 V: ~8 n  C: s    }
   
6 \; h) q$ h9 i0 G6 X+ y6 L    syncUpdateOrder ();
; x) ^. m0 n3 T4 ?2 p3 b& x
2 n3 L6 i3 @" J8 M' z0 B    try {
6 m( l9 Q5 s6 a) K" M( X+ |! k+ b      modelActions.createActionTo$message
0 f% x2 k0 g2 @: O2 w        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
8 T/ ~$ W6 r1 S8 W) R, a4 K/ {3 s        
% I+ t* z: F8 e; F8 Q2 V    // Then we create a schedule that executes the
6 G# b) l+ e/ c0 C( [8 m    // modelActions. modelActions is an ActionGroup, by itself it
4 i# m) {' a( W. y8 }7 a    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
6 ]. w* n+ I  X5 S" {    // modelActions ActionGroup at particular times.  This
    // 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.

% C1 A3 I9 U) H6 ]/ A+ c3 b' y    // This is a simple schedule, with only one action that is
' ~6 ?2 W* c3 E+ t3 V    // just repeated every time. See jmousetrap for more
3 ?( a2 C: S" g3 ^    // complicated schedules.
. o" F& a5 m, q  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
( }4 g! H# p. l4 k1 n9 L* I' n6 W        
    return this;
4 a+ W; }3 Y+ a) _* d$ X1 u  }