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：

/ a7 x3 X2 d+ ^3 F  a# q public Object buildActions () {
    super.buildActions();
3 Z6 u: k/ {$ G8 X# F/ z* I; }3 N( A   
    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
0 y) `8 m& ]4 Y6 V    // 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
- R, W3 P8 @# x3 j7 q  o    // object, or ForEach object in a collection.
        
0 a! N* x9 W9 n9 L: B, |' {% `% m    // 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!
        
: ^1 E' r* g7 v    // Note also, that with the additional
0 G( Y) L" ]* F( R" p" P    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
+ U& M! s3 N% w! a/ h8 ]  u+ e    // systematic bias in the iteration throught the heatbug
1 d( ^) k8 M; W$ ]+ Y    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
5 T# x3 T' M! w2 ?  l; x7 Y: E    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
  O$ H1 U* Z  t   
    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
, j6 b2 X5 a  B: S" W, g5 u9 ~    }
, s- s3 C1 `4 u8 D; V9 l
    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
" a/ S7 v/ u0 m7 [2 t! b  l        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
. P' x, i3 P% K) v6 w5 s& C  T. |                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
$ {  n( B5 K* r. w! \' v      e.printStackTrace (System.err);
3 ^) e& u9 @6 ]5 K* p; M    }
5 G$ R  F/ J$ U   
3 A' A' q0 h2 h; `" E- v4 z    syncUpdateOrder ();
3 t5 s" g3 H/ G
    try {
      modelActions.createActionTo$message
! w9 d$ o9 G& S1 f6 ]% j        (heat, new Selector (heat.getClass (), "updateLattice", false));
; n8 y  \* B6 ?/ g7 n    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
8 }5 e' E0 t' d" I' m    }
. d9 O8 }! R* t8 i, m9 d  {' y        
) j$ {* G# R; \' o: d# G& o% 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
    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
6 z% f* B4 A' X, C, j6 w* ]    // 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.
" O1 J& Q! g2 U4 n
) H$ A! ~3 Z2 W/ U4 x0 t    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
" {8 c8 y9 U9 m7 s% g3 D$ X, O    modelSchedule = new ScheduleImpl (getZone (), 1);
' Y( t4 a2 D' t  H    modelSchedule.at$createAction (0, modelActions);
4 d2 E7 ~" u5 }6 R. ^        
9 ^; h4 B: [4 P8 w/ s    return this;
  }