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 v- U: n1 M* F( r public Object buildActions () {
    super.buildActions();
( T$ {8 s% @! y8 t' h   
, J2 ^  @+ D2 D    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
9 A7 J4 M6 o9 n1 k5 ?! u7 |    // executed in a specific order, but these steps should
    // take no (simulated) time. The M(foo) means "The message
% _$ ~( K* ~" [8 I    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
0 @8 e* I$ ]$ a, p- n        
4 z& N1 u1 I  F3 x. T    // Note we update the heatspace in two phases: first run
/ ]3 \) l6 q6 V0 r3 E    // diffusion, then run "updateWorld" to actually enact the
* z; _0 S( r- Y    // changes the heatbugs have made. The ordering here is
    // significant!
        
    // Note also, that with the additional
    // `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
    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
; l, c5 L  Y/ @    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
0 ?0 n# q/ O& o3 \8 m9 x    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
- R' \5 A7 W# z( D    } catch (Exception e) {
# {5 m( f+ V4 ~% ]% d' b) T      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

    try {
/ k% K$ j# Y  U% M  N      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
9 `3 s5 ~+ v0 G: W( r/ Q8 ]$ |# l        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
+ l3 k5 U8 A- P# Y0 b      e.printStackTrace (System.err);
( Q% ?4 v$ T+ d  a1 q8 I    }
   
. \+ J$ ?  j& M4 ?: z    syncUpdateOrder ();

* {2 Y& o4 d3 p: ~1 ^    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
( ^! q1 z6 L0 N6 n    } catch (Exception e) {
1 G5 s) r3 X& G5 Y& q) E! u; i      System.err.println("Exception updateLattice: " + e.getMessage ());
) n# a0 @! S( Z- E9 b    }
        
+ L! i1 |1 ^  N! }, O* W( [    // Then we create a schedule that executes the
$ _. h4 T; X4 w: ?) ~/ Z    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
8 [$ u+ M% |* U, }    // time, we create a Schedule that says to use the
' e' f6 ]3 k  G# n    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
5 Z% ~" x4 Q' {. `    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
2 N2 d2 v' C3 B7 ]' Z7 H
6 g9 z- d2 `4 x# H5 h    // This is a simple schedule, with only one action that is
0 Q, J8 L: P9 `' m+ \  G    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
% p: Q. `7 Z9 R/ i1 ^* h: ^0 S2 w2 n    modelSchedule = new ScheduleImpl (getZone (), 1);
+ _3 C  f6 {$ [, K: P. ~4 v* q* e    modelSchedule.at$createAction (0, modelActions);
        
  w: I6 V+ e  E7 {& \    return this;
0 ]8 ?" \4 `0 ]5 W) D' |$ U7 C  }