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 () {
    super.buildActions();
   
) @, P& R4 o6 {' j  o8 P    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
, `7 O" D& M' c3 _! v    // executed in a specific order, but these steps should
* ]) K& @3 d" b% S! R: z4 R. u    // 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.
5 E9 Z& r* ~- D4 b9 a        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
! r- i! b- g% J* h5 ^5 E1 ~  Z    // changes the heatbugs have made. The ordering here is
    // significant!
        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
- f' p! U2 ]" H8 M+ `/ p# t4 v    // randomize the order in which the bugs actually run
9 Q7 t6 ]2 |% x! N    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
+ j3 M  g3 Z: `; D    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
, ^9 V; ]: m2 e* K    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
1 z5 a" o" K/ {4 j2 i: u! r4 R' @   
    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
% N8 T6 C& ~2 z/ _* n4 ]1 a    } catch (Exception e) {
5 F& k  r# z$ @" q9 W4 Y      System.err.println ("Exception stepRule: " + e.getMessage ());
$ ~, D% D! D2 p- V0 O4 }1 c    }

2 g0 \' ^2 ~4 U  Q+ v/ g* a4 y    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
+ z- _+ Z3 B7 x% S3 G9 h        new Selector (proto.getClass (), "heatbugStep", false);
+ e  W8 i0 S5 [      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
; O8 K8 ]; ~+ q4 P' n         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
% g: `4 h" w  }: G. K    } catch (Exception e) {
2 ]1 Z1 h" s. ^! `5 u! b      e.printStackTrace (System.err);
    }
   
$ v; p% r- |3 y  }, E  F    syncUpdateOrder ();
9 K& p& ^2 c7 I7 l& J
    try {
  L! n7 c% v3 b. @; \" ^      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
7 ?8 h/ R1 P8 M      System.err.println("Exception updateLattice: " + e.getMessage ());
) R" i5 A! B+ M  C  q5 e* Y8 m    }
        
    // Then we create a schedule that executes the
3 h1 b# s/ _6 p+ C- E$ W1 x    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
/ }0 N. {" N2 @' f5 v, W7 B1 L    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
5 u: C! u* l- |7 b$ ?) E% e    // 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.
4 O& r' D8 u: G8 M
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
. ?; L0 x) S7 A  
" L) z) S& i  b0 K- A7 V- e0 W& Z    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
, U- h0 l+ U3 H0 @    return this;
  }