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：

, j! F0 Y3 s' _$ _! P; H% t" e public Object buildActions () {
    super.buildActions();
  S7 M6 l: B  j3 W/ e4 r   
+ z8 j- Q) L; m4 d    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
    // executed in a specific order, but these steps should
2 w9 N! m  o  O2 d! `* k    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
) x# @* s& l& c, U$ A% D+ C% }    // object, or ForEach object in a collection.
0 B* q; h9 n, e- i        
# q6 z% S2 Z% o    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
; r; ]3 @6 ]# ^& E/ c" O  n2 g    // changes the heatbugs have made. The ordering here is
4 O$ S" J( f8 r4 H2 `    // significant!
" j) [9 }  j7 v- b$ S        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
$ k: T" Q+ x* a2 N3 q    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
+ z: f( d0 p7 n$ Q% e    // list from timestep to timestep
, b/ I/ L6 W' o+ \4 ?        
! p0 c: T& x- l, V; z' p. l    // 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).
   
; _: [: Z. I. z2 _0 x! H8 G; ]    modelActions = new ActionGroupImpl (getZone ());

$ h# l- t9 X$ n$ J0 q% Q    try {
, r# U0 {$ {* d$ p7 T! ]      modelActions.createActionTo$message
& L+ d* m) b0 G" o2 _5 B/ F        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
3 Y; w5 O; m+ L$ H
# I! R6 P/ M9 T' ?    try {
7 b! E5 s2 E3 t* _3 A      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
2 f/ T. d# ~, p- K2 j        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
0 [6 A- t8 }2 j- y& g! |+ m5 v        modelActions.createFActionForEachHomogeneous$call
6 _0 m( I) I8 L8 k        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
$ O+ j) S# g# ?5 _   
$ R: D3 x6 ?1 A( ~! w    syncUpdateOrder ();
) n" B# t9 L7 g+ `. p
0 j3 x4 D0 w" P$ Q) N3 q    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
) r; \6 A& {/ d) _1 e! K    }
        
& L; s" D- p5 y0 c+ F2 B    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
5 N" s( [. ~% w7 b0 N: e; _    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
6 o8 _4 P5 z) n1 s8 Q4 [- ~% T    // modelActions ActionGroup at particular times.  This
6 }) m& B+ I" c  A7 [  _+ _    // schedule has a repeat interval of 1, it will loop every
2 F* c: b8 s7 W6 z) C: q    // time step.  The action is executed at time 0 relative to
5 Y' E7 \1 H6 N/ J& i    // the beginning of the loop.

7 u7 Z3 `/ N* }    // This is a simple schedule, with only one action that is
+ i$ N  R, H& g* ]    // just repeated every time. See jmousetrap for more
    // complicated schedules.
, w* i2 R; G  u( S  
7 w( e2 ?( J0 c8 M+ M/ m* i    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
2 s& E4 n$ y9 Z- w* a/ \9 v2 \  }