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：

; L% c4 P' Q: P, j& N) b: V public Object buildActions () {
. S8 W9 u! p6 W    super.buildActions();
   
  T7 G4 c* f4 Q& J3 U2 o. T- ^7 i    // Create the list of simulation actions. We put these in
6 Y5 ?( `4 y6 K$ P, @3 u    // 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
    // called <foo>". You can send a message To a particular
7 J' M9 I6 Z$ s) Y8 I    // object, or ForEach object in a collection.
2 M7 r8 s: C! s        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
+ }) o& Z0 P' ^    // changes the heatbugs have made. The ordering here is
    // significant!
6 ~  t+ U9 j7 U0 @        
3 K6 a9 A7 o$ q6 B0 R    // Note also, that with the additional
' P/ M$ a. T$ \1 x9 W# V    // `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
        
4 S: L0 _4 O! P) @" y    // By default, all `createActionForEach' modelActions have
: L) Z9 D& Q( Z+ h0 E" q$ X: |5 P% x    // 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
6 M& j' \: i& h) n, ]% I0 D' I6 @    // indirectly by some other process).
6 e9 T/ G9 @7 ]0 C+ D& H# M   
% b1 y2 g+ g- m1 V& f    modelActions = new ActionGroupImpl (getZone ());

    try {
( X& t4 T6 o& \/ ~- Z# q6 q      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
0 I* [- d' V7 l% {      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

" `( O8 e" X% y" c& e! Z4 P    try {
# w+ d/ g& z- s) f1 s      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
7 u- A5 X3 p! N! B1 r: p- U, U& r        new Selector (proto.getClass (), "heatbugStep", false);
# @# m5 |2 {$ S      actionForEach =
" T. Y' m6 r& K( e% z" u        modelActions.createFActionForEachHomogeneous$call
1 m! E$ `) f+ M+ D" J  e; F        (heatbugList,
, K8 ?2 j1 ?& a7 ^         new FCallImpl (this, proto, sel,
  c5 F$ j; j, A# j3 H$ T                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
5 F# @/ N1 k# V: h    }
   
# J& a% D; a) J. I    syncUpdateOrder ();

' e7 _& h/ b2 }5 u& P- ^( Z    try {
      modelActions.createActionTo$message
0 ]" C$ g$ u; i2 \1 O        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
' E5 s0 v2 k: Y: \! r    }
        
    // 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
; [' G' q1 S, K! m2 K; @    // 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
9 c& d" b7 X& Z5 h' d    // 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.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
8 s$ ^5 C  }: x0 N    modelSchedule.at$createAction (0, modelActions);
        
  H  v8 {; x. ^    return this;
& J' }1 B6 Y. h  }