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 () {
! @! M6 \& r" }! J4 `# v    super.buildActions();
   
' ^2 R# r& b8 ]9 X) P7 _4 _  O    // 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
    // take no (simulated) time. The M(foo) means "The message
1 n* p& z1 B# S+ }    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
# Q* q+ v" Y  n        
    // Note we update the heatspace in two phases: first run
( `6 A; y$ p; Q7 |7 g# G    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
    // significant!
        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
; E, M. C& T( p! p% j) y    // randomize the order in which the bugs actually run
, e, y9 c& u2 }1 t8 D& u. Q    // their step rule.  This has the effect of removing any
& l7 ]# U# _! P7 A    // systematic bias in the iteration throught the heatbug
" H8 p. C$ @( |& |9 v# J9 ?# ]    // list from timestep to timestep
7 x& ^5 L' Y1 w% a0 y; g5 ?        
    // By default, all `createActionForEach' modelActions have
    // 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).
   
0 h5 t/ h% U5 n    modelActions = new ActionGroupImpl (getZone ());

1 i7 g. R5 {- t+ |# ?0 P    try {
" O8 Q! }! y  O" S) x      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
) k; [! a+ N. I; F! u( r      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

' i/ P; U3 ^/ e  _7 V" f    try {
5 ]. }+ R( Y& ~  M4 l$ `' b      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
) l! {3 Z: s+ m      actionForEach =
7 I) }1 S8 N$ m* J1 m        modelActions.createFActionForEachHomogeneous$call
8 C+ A, l: j* Z$ S: [        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
- W5 g( i: e+ F" V0 P+ m2 h4 R+ Q! S    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
   
    syncUpdateOrder ();
7 ]6 w7 d$ Y) d7 r' V
    try {
      modelActions.createActionTo$message
) V2 ~  p* i$ a" t1 o3 T* V        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
# D: n1 O+ u4 ?  F+ w- n; z/ n    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
# ?+ q1 a8 [# b" g# x0 o/ n    // has no notion of time. In order to have it executed in
# x) q; J' p3 ]/ l7 i  K    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
1 T: t' l$ W! t8 ?* m5 n% V7 Z    // schedule has a repeat interval of 1, it will loop every
    // time step.  The action is executed at time 0 relative to
4 F/ k- d( y3 l0 b6 m    // the beginning of the loop.
, x3 m. e& o& p; s% q3 o; t
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
& M0 i# I8 P' D% T5 ^    modelSchedule.at$createAction (0, modelActions);
        
! I0 j; q! c3 R5 m& M$ b    return this;
- r1 E7 h% R+ R" d$ h& ]  }