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：
+ ^7 |8 m$ J/ W+ Y  M
) O1 l9 _5 }6 ?! Q, V/ z public Object buildActions () {
( T: m" H  u: T, `$ g0 T    super.buildActions();
- b0 |$ x9 {/ [! q0 z3 b   
    // Create the list of simulation actions. We put these in
. f- D# f2 f) ]) Y6 C* F    // 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
5 y8 J# C6 Y& m' e3 ]! H    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
) O: x* j$ j( L' e9 ?        
& O; I. R7 H9 N; J    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
# R/ R( q) H+ b2 L7 V" A! L( I! L% L    // changes the heatbugs have made. The ordering here is
# _  ]. w* W$ Q. G% E1 E    // significant!
3 `, Q2 N) T' e, Q4 B4 a; d        
    // Note also, that with the additional
/ G0 ^5 ^/ D% V8 a    // `randomizeHeatbugUpdateOrder' Boolean flag we can
3 t: \( ~8 o4 S; l% e    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
2 r3 f& w4 Z& Y3 f: s5 L, o    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
4 Y6 \6 ~9 U9 v' h" E        
  s3 x& t% R3 g$ y3 C    // By default, all `createActionForEach' modelActions have
* C" J2 q; @3 k! X; ^* |' a2 j    // a default order of `Sequential', which means that the
4 X1 s9 ^& p# `7 U. `    // order of iteration through the `heatbugList' will be
. m( U4 M: b; p    // identical (assuming the list order is not changed
2 h$ v, T2 i+ A5 K2 U    // indirectly by some other process).
  n0 q: r3 q2 K! h8 L, u4 S! P7 {   
    modelActions = new ActionGroupImpl (getZone ());
3 O; S# _+ [- [  _, W- E
    try {
% W8 u$ F! I  o# _# `      modelActions.createActionTo$message
4 Z+ v. R; Y8 f5 A. k        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
: X: ~" M' C6 o2 f    }
  |# G. @8 u4 B- `; O+ G  o1 N
    try {
% ~$ [4 |3 A8 e: b+ P* q% @      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
2 p" K; `; d: E/ a; O$ J, |) R; ]        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
, R1 u& t5 J# u        modelActions.createFActionForEachHomogeneous$call
2 N. k+ h  T  p. @: E: h        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
) @+ n% k$ O  h# O% }) w# f2 X  \      e.printStackTrace (System.err);
  V- C# c6 v6 X( }: x$ h  l  P0 w    }
   
; \8 M3 A; t; n: ^6 O7 Q2 h/ a    syncUpdateOrder ();
( y; H; r# v. Q8 O  N; E$ X
    try {
      modelActions.createActionTo$message
5 B; T6 H4 B) P+ a- C        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
* j9 M  H. G, W0 J    }
        
1 P/ x4 J. N' F+ r5 R* |3 U    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
2 ^; p+ E( \4 t$ f5 q2 D    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
1 s2 I) d/ P" a* w) G' C0 p    // modelActions ActionGroup at particular times.  This
& I' u5 @8 T( b7 @  l, C% {( |& }5 T8 A    // 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.
* E9 D5 Y5 d5 _8 E9 q2 H/ G
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
8 |) ?4 k, L# {$ F* D' q4 b    modelSchedule.at$createAction (0, modelActions);
        
7 l& U+ S+ N, l; N& Z2 e7 W    return this;
  }