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：
0 \6 m* P+ J& U: i3 a
public Object buildActions () {
    super.buildActions();
& Z/ [+ e8 t; Z, W   
    // 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
: h1 G5 x5 P$ c2 h4 W+ i5 z- h    // called <foo>". You can send a message To a particular
  w. s" K2 J5 ^% F7 U, j8 b    // object, or ForEach object in a collection.
  J, i6 |" A- m$ P% `0 K+ a( V" z        
& ~- W2 G$ l3 B5 h7 ]    // Note we update the heatspace in two phases: first run
9 }& E7 y8 x4 j6 j" X9 k8 E6 F    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
    // significant!
# T# V2 o+ X0 R' B        
    // Note also, that with the additional
  p3 L, h' ~) N  z% m    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
# x/ r2 l5 R) I; a. c" f. F0 _    // systematic bias in the iteration throught the heatbug
0 l9 I. Q+ h3 }/ y    // list from timestep to timestep
; A! Z! z! f9 }/ D        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
7 q2 ?# S6 l) S% v    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
% h2 d/ O, ^, C    }

    try {
$ U( u, f  a8 X9 A# U. P      Heatbug proto = (Heatbug) heatbugList.get (0);
3 y; W: r5 N1 V2 t0 @      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
9 G% |, o% m3 u+ C+ D0 k        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
9 O: x& H, b( U; f         new FCallImpl (this, proto, sel,
$ s; Z- A: v' [2 `$ z                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
  ~& Q5 X. o# ~  d3 o; {      e.printStackTrace (System.err);
    }
8 e/ g' T+ R) j7 `( x& q# k; h% T7 b8 _   
    syncUpdateOrder ();

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
% ^) G! L$ ^' ~5 i9 e    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
0 M+ x8 }9 D9 c) j6 l    }
8 ?$ j" x8 i2 Y' `& u7 E        
; d$ l2 \5 [% s( R. }  s7 t) l, r    // Then we create a schedule that executes the
5 W5 ^2 E  d* `+ ^- b4 n' T    // modelActions. modelActions is an ActionGroup, by itself it
$ x& \# M) l  x5 J0 i& _4 V    // has no notion of time. In order to have it executed in
% W, R9 e6 ~1 ]9 R! q  z" u    // time, we create a Schedule that says to use the
2 C4 w: J# u# L    // 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
5 v+ K' P- }4 Y    // the beginning of the loop.
: ]) x$ l, K! M, y$ |( X. h& G1 B
: K, L7 [% N' d$ h    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
0 _7 o4 j# e1 H  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
  }