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：
. o+ @6 w6 n5 C, L2 i8 s" x
public Object buildActions () {
  i. v- c) x  V    super.buildActions();
* p: m7 l: e+ \; d   
, p1 v. R* x3 j9 @# c    // 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
+ C# E; b3 x8 E" h  l0 i    // take no (simulated) time. The M(foo) means "The message
( H. n6 J; q! K6 U& p" a2 n    // called <foo>". You can send a message To a particular
) |/ t9 |: T+ F6 K# H6 G  I    // 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
    // changes the heatbugs have made. The ordering here is
    // significant!
        
    // Note also, that with the additional
/ M$ K7 v* Z% T. \2 v/ j4 f    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
$ \5 ]- z4 F5 Q1 A3 i' E9 P5 y$ t& z    // their step rule.  This has the effect of removing any
    // 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
" L( t6 k1 ^7 t5 n% y; [+ _    // identical (assuming the list order is not changed
8 V& ^. O. l, U1 D4 @% p$ f    // indirectly by some other process).
   
/ ?0 {3 z' T( i5 G    modelActions = new ActionGroupImpl (getZone ());

    try {
$ I+ g' N) d" b! \! F      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
7 U; C+ \* B) z: _/ n- W0 L    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
" f, e- b! b+ k/ s    }
. U7 s* A- x! }  w
1 U3 k! z0 N& h( S- b: v. Q, [2 k, T    try {
; W* _, B1 f0 c# [4 X; z7 Y      Heatbug proto = (Heatbug) heatbugList.get (0);
  ]) E3 t1 F' Z( m5 ~3 H( V      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
2 s; n' ^) r, K2 S      actionForEach =
+ Q, }) X  M1 n4 @9 L0 I7 e( v        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
: R) Z. {% u) ]4 m) B5 o+ \         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
6 {  M9 N" d( P9 g  \+ [2 t2 p    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
5 I# u6 t9 P) c0 w0 b  c' \   
    syncUpdateOrder ();

    try {
      modelActions.createActionTo$message
9 d# A. G8 {; M9 t$ l& x        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
) O3 b0 a* @6 s  b6 x* M      System.err.println("Exception updateLattice: " + e.getMessage ());
9 k6 @7 ]7 i( s2 |# a    }
4 F" k* ]" `5 c$ W3 m# u+ A; ]. ?        
    // Then we create a schedule that executes the
. m1 i, F' _# h8 d* ^    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
  {. W' b0 b' M5 P- w& g5 w/ [    // time, we create a Schedule that says to use the
+ [9 m! J9 l5 I    // modelActions ActionGroup at particular times.  This
- [* E8 F) Y; e6 S    // 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.
  \5 ?7 N5 t5 L: Y: f/ ^- a
' r4 M1 n, l5 f9 D    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
" P/ F4 }& a5 I! u2 A+ y- |( E9 d    // complicated schedules.
+ Q* P! @5 }7 W  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
& O  V5 ~) ~2 H! p7 r3 u        
3 l% d- M) t2 ~* }, N; o    return this;
  }