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 S; i6 |' \7 u$ ]# i+ j+ V2 Z4 z public Object buildActions () {
# N# d; E6 M* N% r) F" N2 U- t    super.buildActions();
3 a  l0 ~9 c' O7 E   
    // 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
    // take no (simulated) time. The M(foo) means "The message
0 w5 P6 \' A9 r9 d4 [8 x+ O3 h- j    // called <foo>". You can send a message To a particular
' q" Q/ X$ S! e6 ]! Q( c    // object, or ForEach object in a collection.
0 ^: \0 s* [5 s4 k9 N& Y+ d* @        
& J# \% }3 L( b# K    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
6 g' d/ q. A9 [1 V" h8 R    // changes the heatbugs have made. The ordering here is
    // significant!
( W& E  a- ~) M$ q! _        
* U$ f/ m) ]% C4 A6 G    // Note also, that with the additional
/ n% o1 \1 _: N) B6 k$ ~+ H; W    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
% @( }% E0 Y$ X    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
) s+ r0 }8 ^) ^, D' r  f        
2 V8 p. s+ E# c# `' D& U% m    // By default, all `createActionForEach' modelActions have
- r( J0 l) S7 S  C    // 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
$ z) k/ k8 Z2 E9 Y    // indirectly by some other process).
" M, K% Y7 l8 m, s$ ]   
# Z( t8 e) B# a) {    modelActions = new ActionGroupImpl (getZone ());
8 B% C4 b$ ?; ?( Q* b6 v; M6 M
    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
7 u2 W% G" W- D& Q1 ]" _5 b      System.err.println ("Exception stepRule: " + e.getMessage ());
5 k: ?( m( S. ^9 s2 B+ h, m: R    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
) V3 Y2 H! s$ I, x0 Q, N$ _      Selector sel =
! j- n0 f/ q- ~- h* z        new Selector (proto.getClass (), "heatbugStep", false);
) i( @4 k& c8 h4 o2 b      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
8 U/ B# b! K: L        (heatbugList,
0 [# e, e  C) u* M* `8 ?# H         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
" e! \4 |8 s- W* H! e, G    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
   
/ d  U0 H, `  _/ n# c6 A    syncUpdateOrder ();

. X( p. K1 P4 h9 ?2 R5 ^7 F    try {
      modelActions.createActionTo$message
# S! E' R) G. M  g        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
$ n$ b1 a& d! L& N% K9 O        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
8 e6 q, n- m, ]: D( j. v1 S8 g    // has no notion of time. In order to have it executed in
) H! X3 q# h6 Y3 w1 i% U& d6 W    // time, we create a Schedule that says to use the
# q/ [. j) m7 H9 T% V    // 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
3 n1 Y& b! w* _. S0 H! M    // the beginning of the loop.
  a. Y. ?, K* F
. |! U; N: v' D% X1 x, m7 c    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
, E6 W" X. `6 A5 U/ S. I    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
! k  D9 s, u. y( ^& B        
    return this;
4 J$ P/ C% l) f8 X0 ?8 ~' L  }