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：

5 B1 t/ G& \$ n  k public Object buildActions () {
0 r$ ^8 `( \8 S1 D0 N4 ^, @    super.buildActions();
   
# _& x7 }- h5 P2 q4 H# o& \    // Create the list of simulation actions. We put these in
# y. Z! q& y  E# U+ i- m    // an action group, because we want these actions to be
- s8 w) n  U4 n, E5 W. ]3 e    // executed in a specific order, but these steps should
    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
        
( O3 g& X$ L' b  l# `! q    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
, O4 V+ A6 C  L( W' \    // changes the heatbugs have made. The ordering here is
  c' G* g- H7 B    // significant!
' a/ e$ m9 Q( y) Y. o        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
% n" \7 q+ F+ |; K2 u- J    // randomize the order in which the bugs actually run
( }& q* Z' j' \9 D# v0 P+ u    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
1 }, |3 x, S9 K4 h/ R$ d. o        
! z' u# N0 j4 j3 k4 V. E) z    // By default, all `createActionForEach' modelActions have
0 r- \/ R  z, x3 T+ r' Z+ `    // 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
    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

) J) y+ _, @6 l    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
& ~, _4 R; n  R: T9 w# W
/ m6 E5 P4 c8 M. D  v; t7 y    try {
! D8 e. N  y- H$ c- H      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
* S5 G! {1 S- S/ b% E* j) d         new FCallImpl (this, proto, sel,
' d' I: ^  U! G: o* ~3 }* A                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
   
    syncUpdateOrder ();
, D; @: n# a# C
    try {
$ }4 K3 P) U0 E) W      modelActions.createActionTo$message
! k2 W5 q4 z0 a' L$ @) s1 U        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
" j2 F  O: ~! w1 ]      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
    // 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
0 p5 o. z' g6 C$ P% x    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
5 l9 N/ H# ^/ V/ _2 P    // 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.

  P- k8 w, q: L) f: _$ j    // This is a simple schedule, with only one action that is
5 ]4 A# e0 i9 }( i6 I8 ?    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
3 }% [( x5 F, T1 x# A% H+ j    modelSchedule.at$createAction (0, modelActions);
        
    return this;
, h' t& ^- Y% y6 h8 p9 L4 p; D  }