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：

/ a" J. V- X. g5 j; } public Object buildActions () {
    super.buildActions();
   
    // Create the list of simulation actions. We put these in
) N$ k* y  B- i4 |- l% b    // an action group, because we want these actions to be
6 X5 E" H2 j2 _- e+ M. `. T! F/ {    // executed in a specific order, but these steps should
1 `& r7 ^+ l7 U1 ^    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
2 y6 s& ]" |) n. j    // object, or ForEach object in a collection.
' j+ ^1 D' g# m2 q- b' P        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
7 Z3 v5 J0 q* k5 E: K    // changes the heatbugs have made. The ordering here is
    // significant!
        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
* A# ]; b' E- Z' K3 D2 A    // their step rule.  This has the effect of removing any
* U8 m# K, A& P  L    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
+ T4 g) m7 M' B/ W) [, P# G- W        
" H) f- D* G2 x0 Z0 W    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
& _* D- ^6 z# P$ O    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());
0 n$ {9 [, `. s7 r; `* z
    try {
9 G* m7 |1 Y  F8 X! A      modelActions.createActionTo$message
1 F6 V7 Y' h/ K        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
) p1 v' A2 ]' B      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

( o+ U4 j5 A9 J, p    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
  T% f  u2 Q' r        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
4 ]0 x3 o' C) Q8 E( y% s) H        (heatbugList,
         new FCallImpl (this, proto, sel,
- X  `  S$ w( f" r                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
" z/ ^, r) J. [, V: W      e.printStackTrace (System.err);
    }
   
    syncUpdateOrder ();

/ ~$ N" ]- ~- O! a1 `    try {
" G/ f& K# V7 P+ S+ M/ |/ K) ]      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
, R: ]( D1 X# t7 }8 O    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
9 ?3 M+ z7 ^6 K. W& @    }
        
    // Then we create a schedule that executes the
- Z+ w% E  X' J2 Y$ M    // modelActions. modelActions is an ActionGroup, by itself it
. N5 v% v: e/ M: \    // 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
. [' E5 Z1 F0 y. U    // schedule has a repeat interval of 1, it will loop every
- I4 Y- f( \; X4 N2 e: {3 l) O    // 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
    // just repeated every time. See jmousetrap for more
) W, W7 s- Z* V& `- }8 I! O9 c    // complicated schedules.
7 j% A' G/ q, y+ x* E% A) x; p. R$ ?  
( X% e. e9 q' t5 O) F+ o* i4 O$ D    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
0 X& ?, k7 @5 k5 f  }