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();
! [( c# f( w2 P0 J: q: Z) N( p   
    // Create the list of simulation actions. We put these in
( w4 C, a0 m; ^" i    // 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
& u% b  ?6 Y5 M% C    // called <foo>". You can send a message To a particular
- X- c) y' r) A9 x- ?    // object, or ForEach object in a collection.
        
    // Note we update the heatspace in two phases: first run
4 P4 v8 m% m' f7 b( p0 h# s    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
    // significant!
; J4 T; n* f  j6 l6 C        
    // Note also, that with the additional
( L' r  d/ S) N$ k# b    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // 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
& S4 _0 E! u" i0 G$ S9 l$ r    // list from timestep to timestep
5 A7 g- j* g! O5 Q$ G8 M7 V: U5 ]        
    // By default, all `createActionForEach' modelActions have
! y5 Q2 i2 n* c! M8 h    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
( Q% k4 f4 U$ z    // identical (assuming the list order is not changed
    // indirectly by some other process).
/ \5 Q- D4 E* @% }5 a0 }   
2 U: O  U( }8 i: V* ~# [. ]5 p6 B3 m    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
% u- p7 Z. L9 M3 `9 I5 Z' _        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
) a  F$ ^- e1 ~/ ~6 H+ `9 p      System.err.println ("Exception stepRule: " + e.getMessage ());
' ]+ {( A3 ?8 ~6 y6 ~    }

. F6 G( y, V$ N0 F& B0 C    try {
2 I: n( Z  n; I. N* d3 v+ w      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
9 L$ R# z. ^- O. Y5 N' w+ s1 @" n        (heatbugList,
         new FCallImpl (this, proto, sel,
8 t# T( F5 Z3 Z) a2 x; q                        new FArgumentsImpl (this, sel)));
- T2 [( [1 x, \. ^! l- [    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
4 f/ t/ e( y8 K6 w   
    syncUpdateOrder ();

6 X. A6 y- x5 C  b  d& a2 C' E    try {
/ j6 ?( w9 [3 p- A! \* D* G      modelActions.createActionTo$message
- s0 k; }: \& o8 n  m        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
3 Q" L! X+ u+ v  S        
  b5 K4 p5 ?# }: s9 h1 H. }* L3 y    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
8 Z& g0 R; a! [. n    // has no notion of time. In order to have it executed in
) P. w6 v. B1 n0 B7 T8 w2 D0 T    // time, we create a Schedule that says to use the
8 o: A; `  J* t5 y( [    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
    // time step.  The action is executed at time 0 relative to
# z- b2 Z1 I" s# ~% M    // the beginning of the loop.
7 {; G6 d* E: |& P
' W  Y) V# c% S* K4 E& F    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
( m" I0 h5 e; W; v! [! }- x7 T; H" _    // complicated schedules.
7 }7 `+ k9 }9 e8 D6 k  
    modelSchedule = new ScheduleImpl (getZone (), 1);
) h" x4 ]& p, c- I, I    modelSchedule.at$createAction (0, modelActions);
        
    return this;
  }