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：

- Z* V. q6 c; f public Object buildActions () {
    super.buildActions();
   
    // Create the list of simulation actions. We put these in
1 g+ ?6 c& {5 f, C" F8 d6 |/ N    // an action group, because we want these actions to be
3 {; N# G' K/ q9 P7 b    // 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.
        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
1 q  N0 _) W8 M3 W) l4 k3 v/ K    // significant!
4 e4 R; i5 T5 R' T# w: \) \        
    // 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
2 R6 ~: M  A4 f/ V# A: q( [/ e        
- i2 a- `2 ^* C9 }6 `% R; t# e    // By default, all `createActionForEach' modelActions have
    // 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).
; H; }$ B- B9 U7 c! w$ p9 w: V   
" d  A: M& D% P( {3 U    modelActions = new ActionGroupImpl (getZone ());

# B, o- v$ \( g; m, K    try {
0 a  N" T- [: M2 q. g, C      modelActions.createActionTo$message
: K& [) x- {2 s        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
4 n* k; A6 H( u& }/ o      System.err.println ("Exception stepRule: " + e.getMessage ());
1 v, Q$ m  @9 g7 w) c  d    }

& s1 i& H" G) r3 y& y' ?    try {
% f+ l/ ]3 O- V" k( g& w5 u      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
' ], I% T4 K* |- B; t5 T      actionForEach =
$ m& u* u; C, p7 l* p) Y        modelActions.createFActionForEachHomogeneous$call
/ B* g5 c6 y) n8 `1 L: U0 c) o        (heatbugList,
. Y! k  ^% }, |' o9 `         new FCallImpl (this, proto, sel,
1 X& Z3 g3 V/ ^7 j- [- Z                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
4 I7 b' F* Z1 i; P1 c      e.printStackTrace (System.err);
    }
   
0 N. V* V' S  S, y    syncUpdateOrder ();
' p$ {5 l" @3 O; d! }, K
    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
& I2 q; Q1 H% f8 X5 o; E        
    // Then we create a schedule that executes the
9 X2 w9 f8 g! f; e    // 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
4 N. k; s) s0 P8 A, r2 y& g2 {    // 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.

    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
$ e, M+ s4 ]- b4 x    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
7 Z2 f' C+ s0 D$ ^3 e    modelSchedule.at$createAction (0, modelActions);
        
    return this;
- d! o' p) w2 J) a  }