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
, K4 ]6 W! o* ]' A, I1 t    // an action group, because we want these actions to be
    // executed in a specific order, but these steps should
+ o5 p( C3 l1 j5 W% d( s- O1 j    // take no (simulated) time. The M(foo) means "The message
: b7 W  i+ Z4 Q5 |    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
3 c; F0 r5 q9 A3 C$ c1 y# @6 A        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
# N5 {! `% q1 S; e5 U# G+ h* B    // changes the heatbugs have made. The ordering here is
5 i: S7 p5 j7 d$ L/ S$ _    // significant!
        
8 ~2 L$ S/ ]1 z    // Note also, that with the additional
3 v3 L7 u) L" u2 Z    // `randomizeHeatbugUpdateOrder' Boolean flag we can
, f# C& C7 d7 B7 S    // randomize the order in which the bugs actually run
8 a7 Y9 m9 i6 k2 r6 u% |" ]* ~/ q    // their step rule.  This has the effect of removing any
+ Z* N2 I; }4 H) Z6 R) F8 S    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
( L7 T( q* `* o    // By default, all `createActionForEach' modelActions have
8 Y  d& ^6 I4 j4 ?( ?( l% t    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
  t1 o  f) h; U7 w2 C    // identical (assuming the list order is not changed
    // indirectly by some other process).
, E/ T+ S8 z7 |! v   
    modelActions = new ActionGroupImpl (getZone ());

    try {
5 z0 B+ C" f1 ^' K( v) @& Y, L4 v$ Z      modelActions.createActionTo$message
5 |0 H* ^4 p6 h% d  E% A$ A" [        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
0 N/ [6 I9 y$ y, O! }0 F3 J
: ?4 j; W5 [5 N, U6 a+ c  `" f6 P    try {
. J# O7 B# N7 r7 u      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
8 I& H) |% ~6 \3 S; C. f        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
/ ^: y( ~7 M8 Z2 A. i      e.printStackTrace (System.err);
    }
* G) |" i7 t0 ~% p; e& r/ |% c$ j   
- }4 o* A2 x" P- r/ e    syncUpdateOrder ();

$ ^9 g& x4 I2 t6 l" A  T+ i    try {
* M) n# S# G, s      modelActions.createActionTo$message
7 E/ s4 }' W2 s        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
    // Then we create a schedule that executes the
5 |, {# J) m+ I' P    // modelActions. modelActions is an ActionGroup, by itself it
8 `" a; n* U  a    // has no notion of time. In order to have it executed in
/ `# H. ?; K7 j% H0 r    // time, we create a Schedule that says to use the
) z8 j( [# C8 C9 {1 `    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
( P9 r3 r! e! Q" o$ X
; l( o! C' S% F! Z6 o8 D- C' ?    // This is a simple schedule, with only one action that is
5 I7 b. y" B) N& R* {% Q9 d    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
: V0 ]! E* F% }  _    modelSchedule.at$createAction (0, modelActions);
3 A8 A1 G# E; {4 R+ n        
$ l/ E$ L* M: V. u    return this;
  }