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();
   
    // 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
    // called <foo>". You can send a message To a particular
3 y( i0 C  Y& ~$ H    // object, or ForEach object in a collection.
        
$ {" L5 H4 q1 b: [, s: V8 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
    // significant!
        
/ V/ K: B5 ]& H7 `: y* p0 ?    // Note also, that with the additional
" T+ A3 M0 K0 _  A/ G. r' I    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
; J) X6 C0 V) F- z5 e- f    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
/ ~7 e; ^. w3 T    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
8 Z* j; H" `! n, G    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
" Q( d: [" v4 W; V2 R0 h/ x, _   
    modelActions = new ActionGroupImpl (getZone ());
& H5 L0 W. j- S& F2 b2 M3 O
    try {
      modelActions.createActionTo$message
6 X2 L  ^# G/ n5 V        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

6 D( ^* M6 W- |4 E    try {
7 i/ p& r: D9 Z7 G$ \2 N      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
% y5 o/ E2 y5 s. _        modelActions.createFActionForEachHomogeneous$call
/ H. U! [$ B1 F$ ?9 J        (heatbugList,
! u1 V0 j: A% c- ~- k7 R         new FCallImpl (this, proto, sel,
! {/ n" y& l* j; Y) `. t                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
7 e! `8 V2 f0 c: y3 c  N% a- Y    }
   
    syncUpdateOrder ();
# f  v  b8 `* f3 ]" e
4 \. t' A, B8 d6 g/ a$ g6 C    try {
$ v$ k& v5 d' y0 J      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
4 x; \# G, `1 V    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
# S1 l1 d# @0 u, }8 d    }
        
    // 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
/ q- A1 A. y+ N9 w- B4 W" G    // schedule has a repeat interval of 1, it will loop every
% R) s8 g. H' F4 X    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.

    // This is a simple schedule, with only one action that is
' b* e6 y4 a2 y    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
; Q7 x6 [: [: G' R) H  S0 i    modelSchedule = new ScheduleImpl (getZone (), 1);
  n2 _. ?  L2 L    modelSchedule.at$createAction (0, modelActions);
        
6 K: s& _6 b) o5 ~1 a    return this;
  }