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：

; X: k2 M2 [: u3 Z) b9 f( p" n public Object buildActions () {
    super.buildActions();
% I4 B- O$ V( O9 }" }   
    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
5 z9 W. Y1 Z+ a+ h( g+ R9 k    // executed in a specific order, but these steps should
3 _0 O7 y4 x2 O3 }# W( {  l    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
+ b. O7 h& m& O6 _0 ]    // object, or ForEach object in a collection.
6 e: _( O, l5 o8 o& c        
  j( T, r- N, Q    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
' W* t/ R+ H+ x1 A3 ~& v* \    // changes the heatbugs have made. The ordering here is
    // significant!
5 O  o" u9 i! L        
$ \3 C' X! D: t9 K& Q    // Note also, that with the additional
9 x2 g5 L+ t8 g1 N( b0 U3 [  R    // `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
" b/ `/ B+ S$ x4 m5 f: d& T    // list from timestep to timestep
& H  d5 R# Z  [0 x, T0 c) ?        
9 y& R6 P) i* S* G7 ~    // By default, all `createActionForEach' modelActions have
& d- u1 _# ?0 t$ e    // 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
' m5 }* z$ r. S" o; r    // indirectly by some other process).
7 e. A8 _  {7 i: G  q0 _% A   
/ h( J6 r1 M* O; J& |( r    modelActions = new ActionGroupImpl (getZone ());
# l# _8 A* w- s; t- m8 y
- `' j$ P3 Z% x  Y0 N0 |# Y    try {
  G9 x, W7 z1 {' l4 s% \3 `      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
* l7 s- q9 g, ~0 a  G& B      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
; Q3 U6 ?  l1 f$ c. k1 R, u
    try {
7 j- V: q* U2 r: z      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
! U7 C  X6 M8 m  V& D# h        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
. s4 x6 n1 K3 x7 Z8 W0 ?% i- b" Y                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
+ M  ~$ Z5 s. i, H9 H& r* Q, w; w      e.printStackTrace (System.err);
    }
) T; \6 u+ {' S" I3 [   
    syncUpdateOrder ();
2 J7 a: k9 w! N4 Y0 H9 C
    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
; t) A5 J% }# ~! p! s    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
# G- }# c, L9 e' H% m        
  w/ I/ H8 z) l- r( {. k5 ?8 ?# f    // 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
1 ]  t7 g; I) L    // schedule has a repeat interval of 1, it will loop every
    // time step.  The action is executed at time 0 relative to
) q9 F# f# @) z+ W+ H    // the beginning of the loop.
5 o0 |* _/ S, b% ]7 v8 e
    // This is a simple schedule, with only one action that is
; |! c- a; V0 L! M3 U    // just repeated every time. See jmousetrap for more
/ E: X1 h" b6 t* o6 k    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
# p# c+ w  Y8 S$ I    modelSchedule.at$createAction (0, modelActions);
+ F$ u1 }* j3 ?. |0 g" e; s2 B0 j        
4 P( u! X7 r6 s" m9 U    return this;
  }