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 () {
, g7 s) L: ]5 u0 N! M/ c    super.buildActions();
$ X" O3 J1 q3 w9 R' }   
    // 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
    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
, \1 H& b  ]* U3 e8 ]+ s* r    // object, or ForEach object in a collection.
        
    // Note we update the heatspace in two phases: first run
" U) A4 I+ u9 H: J5 k. A% T1 R4 U7 }    // diffusion, then run "updateWorld" to actually enact the
# P  d' b5 T- V  @$ u+ I  |    // changes the heatbugs have made. The ordering here is
2 F4 e2 z) l1 D) E0 M# E) ~    // significant!
: z* r" i7 u  d3 ?        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
+ E8 s+ z  }1 H! `4 t1 G" v9 u( V    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
2 ?% W8 z6 L1 S    // 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
  m" @6 D6 \0 M7 V# M$ M3 h    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
% D6 m* I# D/ d+ g3 T# n    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
$ y5 a# Z/ l5 l, h+ g! ^    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
4 Y' C' ^- ^7 H2 ^9 s- q6 D    }
8 {1 A) w, r; ]( t% \
. m& o* Z; L/ L, U7 K4 W    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
  h/ X/ O2 s$ q( e; c      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
8 d# p) ~/ y9 g% ?        modelActions.createFActionForEachHomogeneous$call
' O+ i# Z4 D1 @2 e  X; @* V6 {        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
9 ?! s/ k7 q8 ^. E" I1 K* }- K7 V    } catch (Exception e) {
+ f. Q* Y. m% E5 F( c) n) t6 B      e.printStackTrace (System.err);
    }
   
& v* o1 V' M* r. t  k1 m1 ~. R    syncUpdateOrder ();
6 n6 M1 O. }1 V% b* B2 W1 V! u7 E
    try {
      modelActions.createActionTo$message
2 ^# k+ k5 S  a        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
- P* p3 \2 t' S; S( {1 ~. H9 g) o5 g- Y      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
& W) F. k# ~3 t, ^9 [        
    // Then we create a schedule that executes the
5 s7 P3 V, u9 s    // modelActions. modelActions is an ActionGroup, by itself it
4 I$ v3 W" _+ l$ }; H) ~) H    // has no notion of time. In order to have it executed in
  f( ~8 E6 `  v# A& l# l! o    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
; h0 R" C7 s$ Q    // schedule has a repeat interval of 1, it will loop every
& z1 G: A2 }4 a. z% e    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
: s: G5 K+ V2 m2 m
3 B2 n* D; ~# i4 C8 R% h+ k    // 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);
; O0 F2 _& \& J6 h    modelSchedule.at$createAction (0, modelActions);
5 ]) Y8 N. m" e+ R; h        
+ B/ H9 Q; R' n" @( ~6 l* c    return this;
& }  o; n! x3 l9 U3 c  }