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：

public Object buildActions () {
    super.buildActions();
   
    // Create the list of simulation actions. We put these in
5 G/ \! C8 g0 Z+ x) _    // an action group, because we want these actions to be
# K$ }4 ~; k- G! o& P% K* U    // executed in a specific order, but these steps should
    // take no (simulated) time. The M(foo) means "The message
/ }# F1 t. n1 Y" [    // 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
8 D* v/ I$ l  B! v2 ?" ?& k/ i# C    // changes the heatbugs have made. The ordering here is
    // significant!
& g- ~, M' [' x" ~+ D- H0 y        
7 `4 G$ R5 x  B% s    // 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
' q8 H9 |% w4 s6 z# O    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
+ X1 a7 Z' f. _3 u: D, ]  G: s5 R$ C  G    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
$ y$ e. t$ ]& m6 a' Q5 b# ~0 @    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
+ X% c7 B! Z5 K/ p2 g% }) x   
    modelActions = new ActionGroupImpl (getZone ());

5 |# }# v/ e0 V6 J2 x( V6 D    try {
      modelActions.createActionTo$message
* J3 ^! e' p. X- U6 n0 @        (heat, new Selector (heat.getClass (), "stepRule", false));
7 x% f5 S, Z1 i" f    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
2 L6 b  Y' a$ t6 f& T5 f" ]* }      Selector sel =
9 g" g9 I6 _, |        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
% R* ~0 ]( ^. z; Z        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
1 i. K$ t5 W* k3 b1 f8 `   
, F9 h8 W6 Z6 O8 B    syncUpdateOrder ();

4 g7 z, `& ?1 ?, k) [7 f4 A    try {
3 w0 \5 E3 N& {3 Y: B( J% l      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
; J0 F: E" k3 Z* O1 {1 P        
    // Then we create a schedule that executes the
4 H+ G' R5 c1 \, ^2 k& r    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
9 b6 V! |2 \  G) c    // time, we create a Schedule that says to use the
    // 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
    // complicated schedules.
* V0 o: |& }* ?% l7 c/ w* d  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
. I* u  b3 X' b' T; a4 J6 {1 }2 @        
) ?  K, x% T( [' A1 ]' ]) ~9 D    return this;
  }