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 () {
% E; u% m% @& c" Z; S, k    super.buildActions();
   
2 l; b8 u% O* N2 ]! P    // Create the list of simulation actions. We put these in
" S+ d0 ~) A6 L2 H% b    // an action group, because we want these actions to be
' ]+ l& Y) [0 s1 ]0 d6 K    // 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
    // object, or ForEach object in a collection.
# K+ u) Z5 l- ^' j. ^        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
! Y' ]5 B# T9 V, J- U/ c    // changes the heatbugs have made. The ordering here is
    // significant!
% `) q" ~# v) y8 V! R        
. W, B; M1 H4 i2 X. L5 S    // Note also, that with the additional
# J, ]: |1 _0 ?. |5 a: k    // `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
0 p( _4 r' V& e1 ]4 [        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
3 c5 b4 q/ `2 a4 c7 U    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

6 l( N. n) o" G    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
5 U, g. H! w' {9 U7 P7 W    } catch (Exception e) {
  c& l+ r5 U8 w4 Q      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

) @: ~1 D& d8 ]3 k2 i! F    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
, U' h* O% X. @" J8 Q( v, u+ o  V      Selector sel =
/ l  S9 Q# \1 b7 k        new Selector (proto.getClass (), "heatbugStep", false);
9 B8 a! b$ |9 F1 x  A) z$ g8 ?      actionForEach =
" T; R; u- X, U7 ~        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
; \2 \  G" n+ ~    } catch (Exception e) {
6 s5 `% |# d1 ~9 x7 G+ n; }      e.printStackTrace (System.err);
1 [2 y3 m& u) R: o* a8 B- o0 ~2 v2 j    }
   
& W$ G! d* F2 [6 R& I, ~    syncUpdateOrder ();

2 T4 D7 e1 _+ Y6 y6 @9 ?/ G    try {
, Q7 Z! k/ D2 V# {% P1 s& [      modelActions.createActionTo$message
) ], R9 a5 [% n( x9 N) ?        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
; O0 U! ]2 l) ]0 a. C      System.err.println("Exception updateLattice: " + e.getMessage ());
# W/ N$ Y* x$ l- z9 _( I    }
        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
# F& _1 w) ~* c' I    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
$ [/ N* v: q0 W2 Y5 P, _    // 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
% c- B7 ~7 C+ |, W& a4 e$ v    // the beginning of the loop.
+ _) v$ t1 ?# ~) A
7 k+ `2 x2 j# F0 ^    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
) n6 X. a, o  p) J6 M    // complicated schedules.
! P. G8 U8 S3 O$ w& }  
. A- |; G3 d& j$ Q    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
# O4 P$ s9 h2 W! u. Q& _1 C        
5 N1 E) O3 y' L    return this;
  }