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：

! S) J2 Z8 T' P# m0 W public Object buildActions () {
    super.buildActions();
* I( Y  o, A1 b/ K* o. p   
    // Create the list of simulation actions. We put these in
+ b7 i& F& _3 c1 J! s% ]    // 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
& G( J9 m! @+ L: J1 {5 C5 v    // 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
1 {) J. J, \* ~6 }8 ?  R: [    // changes the heatbugs have made. The ordering here is
6 m, n. E' d  c8 q0 s  @& g    // significant!
# E& d+ k! o$ o- ?, _        
5 C6 c* |9 p' G$ m2 E7 i1 b" R    // Note also, that with the additional
/ f3 C8 P. ]5 O+ s7 q% O    // `randomizeHeatbugUpdateOrder' Boolean flag we can
/ m  Q: d; w) y; W2 ?* H    // randomize the order in which the bugs actually run
' Y3 {) {* o& R) ]5 B& z, L    // their step rule.  This has the effect of removing any
- x2 }4 _; C9 A( G- g  N7 u    // 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
    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
1 C4 {  W! `) v9 C8 O    // indirectly by some other process).
5 D+ i+ o2 y. x% d' X- z& l! ^  L& s   
; z9 r% a$ z8 n6 v; X2 J    modelActions = new ActionGroupImpl (getZone ());
- B0 H6 c5 I4 j" A' e8 X; i9 J
: |0 \# W! W- O# `, H/ C* F    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
  p- M. O$ I. G. K$ E: e      Selector sel =
3 f8 L0 @4 O2 x1 {! F( }        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
6 u- ~& u# K7 y                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
) q5 m  E* H+ O- a$ W  o$ A3 m% n    }
   
  R+ J* T" r. i  ~, |: s1 H    syncUpdateOrder ();
: I0 x+ {/ q- g+ ~
- C: c9 e. }- ~' R2 _    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
5 y. o2 P: O, S- ^) N$ |      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
! {0 s" _5 _5 P7 l- q+ X' Y9 U' x$ t    // 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
    // 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
0 D  L3 Y) b, y- i0 [+ P. L/ M0 o    // just repeated every time. See jmousetrap for more
    // complicated schedules.
' F/ D* P! S  w9 }( O  
; e3 c; d) H  X; a& S; d    modelSchedule = new ScheduleImpl (getZone (), 1);
- j1 {8 p; N0 o% X    modelSchedule.at$createAction (0, modelActions);
! T3 B5 c9 O7 m8 j! R" ~        
    return this;
4 b$ u7 \; @4 v8 O, M$ E0 n  }