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();
1 R8 k. o) ^' z! _   
; A6 @% I+ Q5 i8 S6 D$ D4 X    // 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
& W. W3 |; j' N, R3 u    // take no (simulated) time. The M(foo) means "The message
0 N* G& E) S2 s    // called <foo>". You can send a message To a particular
$ `7 Y! k- _0 A9 O    // object, or ForEach object in a collection.
        
9 q& R9 D) E* i* I7 Y8 ~3 T% v& u    // 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
( o9 Y) S% t7 p' s    // significant!
2 D1 Y9 ^% }: l, J1 C0 S        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
( \/ W" U9 R3 Q+ c) E6 i    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
  F7 h! m+ |: P# h: f    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
( W: m* q% ?9 R3 Z( l4 k0 c/ g* Q    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
* v; i" J1 P) i   
0 C+ _- d- K: i. X0 b6 _    modelActions = new ActionGroupImpl (getZone ());

    try {
5 ^  a1 C* q/ `      modelActions.createActionTo$message
2 X# g- B6 M, t! t9 Y        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
9 N6 C/ F, U1 c2 ]! M8 E  O      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

) d+ Y9 }7 m3 }6 e- L    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
3 {/ y, P* K5 X4 V. t        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
  M! ?$ s6 J, G! }9 x- U$ z         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
$ u& w4 v# I0 v3 B; D: t, m    } catch (Exception e) {
1 o# n% ?9 U( x      e.printStackTrace (System.err);
    }
   
    syncUpdateOrder ();
$ ~' e2 P4 n) ]/ ?4 l1 S0 u
    try {
3 F, o) B: g& B, c6 [# ^- ~      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
$ b5 n! m6 |7 s5 U. b/ Q2 E    }
        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
* y4 |) H6 V1 o0 m! Z  I    // 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
. b* Q" \9 y( v& f0 `    // schedule has a repeat interval of 1, it will loop every
/ u/ q# R8 |" D" P: X; [    // time step.  The action is executed at time 0 relative to
6 l' Z3 M( a4 R, D    // the beginning of the loop.
$ j! J: @; N  h* [3 M* Y2 \) v& }
+ h+ o% e! F4 I- g    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
+ |. K! J$ }. w  g8 E5 u    // complicated schedules.
- }* g# E' J3 F6 G* y4 t! o  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
  }