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 () {
- b/ t9 T* ?* c7 m8 b5 b    super.buildActions();
   
& {" F' A% U/ j) _& \, D; I+ v0 q    // Create the list of simulation actions. We put these in
2 I" t9 Q4 f% k+ V    // 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
+ s: k% `8 s3 P  L4 X; @# y    // object, or ForEach object in a collection.
/ n7 E, U% K! c: @+ {        
    // Note we update the heatspace in two phases: first run
  ~* b0 ]% A1 W/ |; C    // diffusion, then run "updateWorld" to actually enact the
/ q( a$ B3 H9 `    // changes the heatbugs have made. The ordering here is
5 q7 j' O# [# ?, }    // significant!
. i$ V+ i7 n2 f5 l8 y" N* {        
    // Note also, that with the additional
2 [6 ~6 U- |& Q9 ?2 s5 @    // `randomizeHeatbugUpdateOrder' Boolean flag we can
  Y9 @8 [6 K: z) d' u' D8 M    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
& w7 b+ k, B$ Y$ b  S# c    // systematic bias in the iteration throught the heatbug
7 Z2 C4 W) p' d. P. C/ `' }    // list from timestep to timestep
        
+ A- _9 o3 d+ }: t8 K2 z! T; e    // By default, all `createActionForEach' modelActions have
( N4 N& `2 d3 W0 B7 F! p! `    // a default order of `Sequential', which means that the
7 S6 k1 n( S/ z6 q    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
" P' k4 u2 r1 p  b. P' q    // indirectly by some other process).
3 x, H3 A8 [9 W+ Q7 b   
    modelActions = new ActionGroupImpl (getZone ());
  x* R/ Y3 O% V
    try {
! ~2 ^7 m, X3 f. w8 {      modelActions.createActionTo$message
6 w: d! F6 v* R        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
( V& G! [  ^& q      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
# h6 E8 [1 Y" p
    try {
  ]' T  [. t  b4 z2 O* p8 w# k& w      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
. f& i6 H8 Y) `' k% i        new Selector (proto.getClass (), "heatbugStep", false);
1 G3 J6 A& E8 h* Q2 k3 N9 C      actionForEach =
; N& M. j% S6 X2 B        modelActions.createFActionForEachHomogeneous$call
7 v2 O- p# M9 a% [, w+ g$ F        (heatbugList,
         new FCallImpl (this, proto, sel,
7 J; B$ D. u) U$ D                        new FArgumentsImpl (this, sel)));
# y! j' w7 W+ A9 U' X- s    } catch (Exception e) {
      e.printStackTrace (System.err);
0 g: L) H; g) Q    }
   
' _' D" T* ^3 d) N    syncUpdateOrder ();
' i! T5 W8 k- L$ ?1 ]
, {! F7 ?) ~7 A6 e    try {
8 h! E2 u' l% D* n8 \1 Z: {      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
9 g1 {9 N& b' i+ V4 a, _    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
  n9 J  h( I$ s+ x7 X  k' o! D        
    // 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
) ?1 `% o4 ]- c2 C9 h! @    // modelActions ActionGroup at particular times.  This
- y  Q4 u$ \4 ]$ L. c& C: N  o    // schedule has a repeat interval of 1, it will loop every
+ x6 W8 T7 Q2 P( ~    // time step.  The action is executed at time 0 relative to
# ?( D' f  f" x5 a2 ^9 U* w6 z) }& w    // the beginning of the loop.

! W+ e7 X; y+ r" [* A- f; [    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
" c( [7 l, P8 v4 h6 T& }+ w( W    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
  }