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 () {
, f9 z) ?& O* S6 S    super.buildActions();
   
    // 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
5 \% t& w" B" a- k3 y" Y2 z) t    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
        
$ y8 h% h' K! I    // 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
5 I) }- e$ f! G9 o0 e# C, E    // significant!
        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // 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
- k$ t+ \# J) C) M) v. u5 v; F    // list from timestep to timestep
  q6 @% g. @" D2 s( X' e  o! F        
% O" G, _" k/ `- D* i    // 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
# r. |# F1 }- ?    // indirectly by some other process).
/ H, q, g9 W+ O9 D2 Y8 r% D   
    modelActions = new ActionGroupImpl (getZone ());

1 |- V7 Y) g# j( j2 A! }1 ?' o    try {
      modelActions.createActionTo$message
2 ]4 K9 I: y- L. b        (heat, new Selector (heat.getClass (), "stepRule", false));
5 v& G3 W& r  l    } catch (Exception e) {
/ p2 ]# s. U0 x$ D      System.err.println ("Exception stepRule: " + e.getMessage ());
* b, g" e2 I$ I, B% [7 R) g    }
; ?* T* D1 B/ h9 ^
    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
4 Q+ \/ X8 S9 u# y1 J        (heatbugList,
5 b) i* u6 H! k& e6 K         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
% ~; i, a7 G5 K- {9 z    } catch (Exception e) {
: c: _, [+ F4 m" B      e.printStackTrace (System.err);
6 v- A% Q- a1 Q" a. K! t' t    }
% C, z7 i' f7 D% V   
! b2 v, r6 p5 Z+ P( V    syncUpdateOrder ();
$ m- U: a: o8 B" [% z5 t2 o
0 \4 ^2 }! \; q1 t4 V& V    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
" P) R4 [8 c; I* A) d    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
' P% I/ [' {2 c& n5 h    // has no notion of time. In order to have it executed in
7 H% X+ ]2 ?: b* B* u) n& a    // time, we create a Schedule that says to use the
5 s2 X2 s* X7 O$ R" y# S    // modelActions ActionGroup at particular times.  This
, G1 N  X# S* M+ m    // schedule has a repeat interval of 1, it will loop every
2 R& A. V9 z# h- W0 Q8 D. `5 R5 C& \    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
' [2 t* k  K& _: V, p
1 ~( _- l: U. A" p    // This is a simple schedule, with only one action that is
) T/ [. l- t% l5 j& e) V; ~    // just repeated every time. See jmousetrap for more
6 Z8 e& m  F$ t5 n, I    // complicated schedules.
  
% y! w$ v* l' [    modelSchedule = new ScheduleImpl (getZone (), 1);
) `. S1 c+ A* a9 t0 f% j- N, I    modelSchedule.at$createAction (0, modelActions);
        
6 }$ E' y; h5 w% v    return this;
0 m5 b, r/ F! @# a9 _  }