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：
& W$ Q" I  Q  I; @' \
public Object buildActions () {
    super.buildActions();
   
& M3 I/ o  M3 b    // 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
: k8 S  ~/ M: c% \7 [4 t    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
. F5 U; M/ k- t" r9 j        
    // Note we update the heatspace in two phases: first run
2 f7 b# k, q3 O    // diffusion, then run "updateWorld" to actually enact the
7 j8 {8 Z7 t5 O3 s    // changes the heatbugs have made. The ordering here is
    // significant!
        
) k  {! ^8 g. S: G, O    // Note also, that with the additional
6 J0 _1 y' M  |, D) K6 r- h    // `randomizeHeatbugUpdateOrder' Boolean flag we can
7 Y# m% T# Y0 c; B  |! ~) y" M    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
$ M. `1 k, f; _3 o. x    // 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
" s2 k3 _8 ]: K% N1 r    // order of iteration through the `heatbugList' will be
, m3 D! d  e( d6 j( z2 p    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
! M3 I: Q% i& ~! i    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
& n1 Z& b; Z8 H( x        (heat, new Selector (heat.getClass (), "stepRule", false));
0 j2 U5 y* s4 ]7 N# Y    } catch (Exception e) {
; t6 R) h% I  K7 C; K* L8 S! ^3 I  P      System.err.println ("Exception stepRule: " + e.getMessage ());
8 t. ?5 p7 J+ f6 M& f2 Z    }
+ h# K: E% y$ l: k
    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
/ y* }" j, T+ K. p( O" L( G      actionForEach =
3 |- Q7 |$ y0 L9 u* t        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
1 i8 |) {* r) D. B8 f: F+ _         new FCallImpl (this, proto, sel,
3 j) _6 o( x4 p7 B                        new FArgumentsImpl (this, sel)));
9 f4 w) T  \! a- r    } catch (Exception e) {
      e.printStackTrace (System.err);
3 r! L, _3 Z! }5 k7 n. d1 _    }
   
    syncUpdateOrder ();

    try {
' P- M' o$ w  _      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
9 e# [, p9 q; R8 A    } catch (Exception e) {
! U, G$ S, L: _" @& e6 i+ r9 H, ?      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
1 f* N, ^( }- N) n! g" ]$ D        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
' r2 x& X3 [, H8 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.

4 R0 c  C8 `3 I* l* j0 v. q, p    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
) ?6 d! v& d. P8 K2 Q    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
- N0 r+ ~+ ^3 T0 S! w        
    return this;
3 T4 T9 P* y% i) O- \  }