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 () {
. [7 z, H- R4 ^    super.buildActions();
   
    // Create the list of simulation actions. We put these in
$ I# @8 L; X* b8 ^    // 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
    // object, or ForEach object in a collection.
$ C9 T4 {# _/ O7 g- ?% L        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
: x; I  h  V+ {8 h, `    // changes the heatbugs have made. The ordering here is
    // significant!
" ]4 |( e/ X2 d* a        
( v' l- Q) F$ v/ Z    // Note also, that with the additional
8 p, X! s8 X- u    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
9 N% M5 b$ n6 b5 G6 ^    // systematic bias in the iteration throught the heatbug
) k0 a# K$ g; y8 I1 y    // list from timestep to timestep
4 i* p" k$ E8 Z) w  [; C1 ^7 N        
    // By default, all `createActionForEach' modelActions have
. r; \/ q" `/ ?, C5 f6 |    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
. M- r3 o- N- ]$ |# v9 U    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());
0 g5 m  O3 P4 w% [" \
; M' d4 a- ?4 P) A6 b/ g    try {
      modelActions.createActionTo$message
0 g6 ?5 ]0 a. N; J2 d        (heat, new Selector (heat.getClass (), "stepRule", false));
+ y$ s9 o( ]/ V: B4 A( `5 Z" b3 I! v    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

- |7 a5 h+ z* {$ o& g, m    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
* Y8 L! \' Y6 O. h1 f7 y5 a' w. B& B      actionForEach =
: D# }: q6 i5 `  L( \        modelActions.createFActionForEachHomogeneous$call
3 g* w5 `; E, n8 J3 b7 P; l- u        (heatbugList,
         new FCallImpl (this, proto, sel,
# k3 H& S" L  x; p* e# }2 `6 O                        new FArgumentsImpl (this, sel)));
' v, ?$ _! o: Z4 Z, ]    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
   
    syncUpdateOrder ();

5 e( c) T6 a7 d: z    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
. r2 L% K+ m6 j1 i% w# N    }
4 e) u' H4 b  t9 z. H; c  C. G/ {        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
7 E" t& i: j, h2 N0 V6 C    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
    // time step.  The action is executed at time 0 relative to
& L- o$ Q8 e. f4 @/ W  j    // the beginning of the loop.
0 p8 ^/ V; p5 [. Y' o
    // This is a simple schedule, with only one action that is
; [! z* w9 r: I* B8 _8 H    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
! c  Z# _# E6 E        
( N/ ?' A8 B# ^6 J    return this;
  }